BACKGROUND OF THE INVENTION To fully appreciate the invention, one must understand the nature and operation of guards and interlock mechanisms and their great importance to our heavily industrialized society. There is a constant and continuous need to work on industrial equipment in a quick and efficient manner without jeopardizing the safety of personnel. The present invention is directed to testing systems and mechanisms for ensuring the integrity of guards and of interlocks so that they will function correctly with the passage of time and without the need to open the guards or disrupt the operation of the machinery guarded by them. Interlocks may be any go not-go device, and they can be mechanical, electrical, electronic, electromagnetic, magnetic, pneumatic, hydraulic, etc., and their combinations.

To fully understand the various ramifications of applicant's novel testing systems and to employ same, one must have a basic understanding of the way guards and interlocks function and to provide this assistance, there are provided examples of guards systems that are used without interlocks and guards utilizing various typical types of interlocks that have been modified, where necessary, to permit testing.

The current state of the art for testing the electrical and electronic components of the safeguarding systems is quite advanced. Commercial self testing systems are available which continuously or intermittently, remotely or proximally check for electrical/electronic faults in the system for single or multiple guard closures, during the running of the machine or when stopped, with the guard closures closed or open. If a fault is detected during the running of the machine, the machine is stopped. If detected during stoppage the machine can not restart until the fault is corrected.

However, the state of the art for testing mechanical components of the safeguarding systems is very primitive. For example the previously mentioned commercial self testing systems are not designed to detect failure or breakdown of the mechanical components of the safeguarding system while the machine is running. For mechanical failure or breakdown to be revealed to its electrical/electronic sensing system the mechanical exercising of the guard closure is required. There are currently no provisions or devices provided to exercise the mechanical components for testing purposes during running of the machine probably because such exercising would stop the machine. If the machine is stopped and the guard closure is opened then closed the electrical/electronic test systems will detect mechanical failures or breakdowns in the protective system.

There exists the obvious approach for testing the mechanical components mechanically by opening and closing each guard closure manually or automatically to determine if the machine is at rest when the guard closure is first unlocked, if power is interrupted whenever the guard closure is open, and if restart is allowed immediately upon reclosing. This is not a practical testing system, except in very restrictive circumstances, e. g. where there are few guard closures and generous amounts of time available for testing.

Accordingly, it appears to be very desirable that there be a test system for the mechanical testing of the mechanical components of safeguarding systems during running of the machine to detect if they have failed or not. Such systems to be most useful must be capable of testing the machine while it is running without stopping it.

In addition it would be desirable if the testing of the guards could be done in conjunction with the testing of the interlocks systems which are present on machines adjacent to guards to shut down machines when the guards are opened if the machine has not previously been shut down and prevents the resumption of powered operation of the machine while the guard is open.

Generally speaking, all interlocks contain a sensor whose state is changed when a change of the relative positions of the interlock sensor and the guard it is acting on takes place such as by movement or the state of the sensor is changed when, through some means interposed between the sensor and the guard, the guarded space is accessed or breached. It is the change of state of the sensor that is utilized to change the operating state of the machine or to shut down the machinery posing the hazard in the guarded space.

For instance, if the interlock sensor is a normally open push-button switch which is kept closed by the guard then, when the guard is opened, the change of the relative position of the guard to the switch allows the push-button to spring open, causing the switch to change from the closed to the open state and thereby to change the operating state of the machine or turn off the machine.

Similarly, for example, if the guard and interlock system is a light curtain, the curtain of light beams serves as the guard and one or more light receptors serve as the interlock sensor. When an object breaches the curtain, the light path is changed, shading some of the receptors, changing thereby the state of the light sensor.

Various types of interlock mechanisms have long been used to change the operating state of the machine or to turn off a machine when an operator has to do work in a space where there are moving parts or other hazards to insure that the operator will not be injured when working in the normally guarded space or on the machine. Safe industry practices require that exposed moving parts must be shielded by guards to safely prevent personnel from being injured by coming into contact with hazardous areas of machinery.

Needless to say, safety around operating machines has long been a concern in our heavily industrialized world. The design of highly efficient and effective interlock mechanisms that have a high degree of integrity so that they will always act to shut down or otherwise control machines when work is to be done in a space in which there are moving parts and/or other hazards have resulted in continuous development to produce a better interlock. New harmonized European standards and worldwide safety regulations stress the need for proper safety interlocking of machinery.

The integrity of a safety device is defined by its ability to perform its function without failure or default. The greater the risk that exists, then the greater must be the integrity of the safety interlock system required.

There is an all pervasive need to insure that the guard is closed when it is supposed to be closed and to produce an interlock that will not fail when called upon to perform. While significant strides have been made, this has not been accomplished, and thus there has long been a need to be able to quickly and efficiently periodically test the guards and the many and varied interlocks disposed about machinery to determine whether they have failed or not, and to undertake remedial action if the guard is open or an interlock has failed, so that when they are called upon to act, there is a very high degree of certainty that they will do their intended job. It is to this end that the present inventions are directed.

It is not uncommon to enter a plant and observe signs that state in bold letters that"safety is our number one priority"and thus a great deal of attention has been paid to interlock mechanisms to insure that they are located in any area where someone might come in contact with a hazardous part of a machine by opening a guard, but insufficient attention has been paid to testing the guard closure and interlocks to ensure that they maintain their functionality and integrity. In most of the industrialized countries around the world, there are laws and regulations that require that exposed moving portions or other hazardous sections of machines be covered by locked or movable guards equipped with interlocks to prevent entanglement and injury to the operator by the moving and other hazardous parts of the machine, but unfortunately this is only part of the story if there is not a continuous testing program of the guards and interlocks, since if not tested they may be giving a false sense of security.

Locks on guards have been used for a long time. Such locks will usually not open until powered operation has been interrupted for a predetermined time interval to permit the machine to totally run down or to change its operating state to one eliminating or substantially reducing the hazards of the guarded space. Unfortunately locks may fail and it is essential that tests be periodically conducted to insure that the locks are operating properly to maintain the guards closed. Such locks should not be opened until both powered operation has been interrupted and the moving machine parts have come to rest. The state of rest is generally established by zero speed switches or motion detectors. Sometimes interference devices are inserted into the machinery to assure that motion has been arrested (inserting a stick into the spokes of a wheel).

In the majority of the cases where locks are used, an interlock is incorporated to prevent the machinery from assuming powered operation while the structural guards (barriers) or non-structural guards (light curtains, for instance) are open or out of their protective status. This is where the reliability of interlock mechanisms plays an important and vital role. When called upon to function the interlocks must act to preclude machine start up under powered operation. Interlocks must perform their intended function or else personnel will be placed at risk.

It is very common to observe signs posted around machinery cautioning operators to"shut down the main power to the machine before doing any maintenance or repair work."But even with the proliferation of such signs, the admonitions are often ignored and to a large extent the machine operators rely on the functioning of the interlock systems to prevent their being injured, which further emphasizes the need for a testing system that will insure that the interlock will function when called upon.

Furthermore, even with a well designed interlock system other considerations such as time pressures, production requirements, etc., are dealt with by clever personnel who can and may circumvent the interlock mechanisms by preventing the interlocks from functioning when opening the guards or actually bypassing the interlocks so that the machines will continue to operate while they are working in an unguarded space and with no assurance that the interlock is restored to its functionality afterwards. An interlock that is bypassed has the same functional characteristics as one which is stuck or welded or frozen so that it will not change states. Consequently, the present invention will detect a bypassed or sabotaged interlock as part of its normal testing capability. Once a bypassed interlock is detected, one may either preclude further powered operation of the machine or the structural guards or barriers may be locked into their closed positions until the bypass is removed. Sabotage can never go undetected because it is a long term condition that any regular interlock testing program will uncover. Bypassing, which is a temporary condition, cannot remain unnoticed for longer than one testing interval. Frequent testing will all but eliminate temporary unauthorized bypassing of the interlocks.

It is a gross understatement to state that industry has needed for a long time to quickly, efficiently and periodically test guard closures and interlocks either automatically or by simple manual manipulation with or without requiring that the guard be opened. Locks and Interlocking mechanisms like many other devices are capable of getting stuck, worn out, becoming inoperative, or failing to function for a variety of other reasons that will preclude them from operating successfully when called upon. Unfortunately, guards that can be opened and interlocks can present a false sense of security to one opening a guard on a machine believing that either the machine will shut down or that it will not restart so that one need not be concerned about beginning to work in the now unguarded space.

Even though there has been awareness of the potential malfunctioning or circumvention of interlocks, there has been no readily available means for quickly, efficiently and repeatedly testing if the guard is locked or interlock devices to determine and insure that they are functioning satisfactorily. Conventional available methods for testing guards have been mentioned earlier and the testing of existing interlocks include (1) starting the machine and laboriously and manually opening each guard to determine if the machine will shut down or change its operating state as required beginning with one guard and then starting the process all over again with the next guard or (2) sequentially opening the guards with the machine in a shut-down position or the changed operating state and attempt to start the machine or to restore the operating state to determine if the interlocks are functioning properly. That this is time and labor intensive therefore costly and adds unnecessary wear and tear to the machine is self evident. The various testing procedures could expose operators to a moving machine and other hazards when guards are being checked or a defective interlock is being tested.

Regular verification of guard and interlock integrity very seldom takes place because it is time-consuming, interferes with work schedules and may be otherwise difficult to perform, thus leaving guards and interlocks dormant. Since testing of guards and interlocks tends to be neglected, then when they fail due to various causes, the failures remain undetected and the hazards they are supposed to protect against become unprotected or compromised.

Also, since guards and interlocks may be remote from the machine operator, extra personnel and coordination is required. Such additional effort and cost provides an additional excuse for not testing or extends verification time intervals. Unfortunately, this is further exacerbated by those personnel that circumvent the interlock mechanism in order to save time, or work in the unguarded space when the interlock mechanism does not function properly, so that they will not be"inconvenienced"by going to the main power or control source to shut the machine off or change its operating state. Operators may consider guards and interlocks a nuisance and will not even report malfunctioning guards or interlocks. The present invention will also uncover temporary bypassing of the interlocks within the testing interval set by a program unit.

It can be appreciated that if repeated testing of the guard closure and interlock systems can be accomplished to insure proper operation, that the operator will"be saved from himself'in that his reliance on the guard and interlock always functioning correctly may almost be justified. An ongoing quick, and efficient testing system to maximize one's assurance that the guard and interlock systems are properly functioning as well as to detect malfunctioning guards and interlocks will go a long way to eliminate or substantially reduce the safety hazards that will occur by malfunctioning guards and interlocks when operators are unwilling to go to the main power or control source and lock out the machine or change its operating state before beginning their work in the hazardous space guarded by the guard and interlock. There has also long been a need to automatically lock a guard in closed position when an interlock malfunctions to insure that personnel will not be injured.

It is the aim of the present invention to provide test mechanisms and systems that will ensure confidence that reliance on guard and interlock systems to perform their tasks when and as received is not misplaced. The invention does this by detecting and identifying which guards and interlocks and their systems are not faulty and which are, and by providing remedial means and actions to those interlocks and systems, and the barrier guards they protect, which have been found faulty. Furthermore, the invention provides the methodology to do the testing, and to apply and then to maintain the remedial actions and means for as long as necessary, without interrupting or disrupting the operation of the machinery. This allows for the scheduling of maintenance, repair or replacement of faulty interlocks and systems at times compatible with the operation of the machinery.

For purposes of this application, the following meaning of terms and expressions is intended here and elsewhere in the application.

Reference to the term"the change of state of an interlock"and similar terms shall be construed to mean a physical change of state of the interlock and the corresponding intended consequential direct or indirect change of state of a machine controlling parameter, most often an electrical parameter, such as, for example, current, voltage, resistance, inductance, impedance, and magnetic field associated with an interlock. For example, and without limitation, a switch of an interlock may be opened or closed, representing physical changes of an interlock producing a change of a machine controlling voltage or current from a first state to a second state.

If opening of a guard is stated or referred to, it shall be construed to mean opening, moving, removing, disrupting, or otherwise breaching of a structural or non- structural barrier guard. Any of these terms, when mentioned in the text, should be understood to be interchangeable where applicable.

A reference to shut down and/or lock out of the machine or machinery shall be construed to mean that, or the alternate of changing the operating state of the machine, machinery and/or its system without shut down or lock out if desired and applicable, and as consequential or by design substantially or completely reducing the hazards of the interlock guarded space.

Throughout this patent application, failure of the guard and/or interlock and/or its system shall be taken to mean a failure of the guard and/or interlock device and/or its system and/or failure of the testing device and/or its system.

SUMMARY OF THE INVENTION The present invention relates to system for a) testing a guard closure that is not protected by an interlock b) systems for testing interlocks and novel interlock testing constructions c) systems for testing closures and interlocks and d) novel guard and guard- interlock mechanisms.

The novel system (figure 2) for testing a guard closure with a guard closure lock that is not protected by an interlock and includes the utilization of a program controller that will be connected up to a tester probe that can take various forms, which probe is to be mechanically moved to engage the guard closure. An example of a testing unit is set forth in figures 30-32. The controller will be programmed to activate a guard closure test with the machine running and the guard closure lock allegedly latched. The first test will be to see if the probe will deploy so that the testing can take place. If the probe does not deploy, the guard closure cannot be tested and its failure will be so indicated at the program controller and will call for the scheduling of the necessary tester repair or replacement. If the probe does deploy then a sensor will indicate that the guard closure opens or is open or remains closed. If the guard closure is open the guard closure will have failed the test and if it is not open it will record that the guard closure passed the test. Following this test the probe will be retracted and the sensor will so advise the controller that the probe did retract or did not retract. If retraction of the probe did not take place the necessary repair and/or replacement will have to be scheduled to occur. If the closure passes all the tests it will be so indicated. If it did not pass all the tests there will be a suitable"test fail"warning indicator and depending on how the system is programmed the machine will be shut down or will be permitted to continue to run with the controller indicating the failures that did occur. If the machine shuts down, the guard closure testing system will be deactivated. If it is not shut down the program controller can be scheduled to continue to sequentially test a number of guard closures until the last guard closure is tested. At the completion of the testing of the last guard closure the guard closure test system will be deactivated.

Another aspect of the instant invention comprises a testing system and mechanisms therefor which utilize the relative nature of the position change between the interlock sensor and the guard or, where applicable, the interposition of some means between the sensor and the guard, or any other suitable means to change the state of the interlock sensor. This is the common nature of operation of interlocks of all types. Essentially the system provides for remote or proximal testing sensing this change of state with or without opening a guard, as desired, and with or without shutting down the machinery or changing its operating state, as desired, during testing. In addition, the system can provide for preventive locking of the guards during the test and/or in the event the interlock system fails the test.

The position change test mode is accomplished by a test system including an interlock and mechanism which is designed to impart to the interlock sensor portion a position change or relative motion, which normally would be caused by opening of the guard. It thereby allows the interlock sensor to change its state as it would in its normal interlock operation, and can be done without the necessity to test the interlock by opening the guard or it can be designed to move the guard to accomplish this. Where required, such as with the light curtain example of a non-structural barrier referred to previously, the test mechanism does the testing by interposing a probe in the path of the sensor. It is to be noted that the test system may also be designed to bypass the interlock being tested so that the machinery will not be shut down during the interlock testing phase and, if so desired, remain bypassed after the test has been completed and a faulty interlock has been detected. This latter approach, referred to here as interlock maintenance standby, allows for the scheduling of maintenance, repair or replacement of faulty interlocks at times compatible with the operation of the machinery.

The state of the interlock can be sensed and it can be determined whether the interlock has changed or has failed to change state. Corresponding test system output signals would indicate, inform and/or record whether the interlock has passed or failed this test. After completing this phase of the test, the interlock is moved by the test mechanism to its original safeguarding position against the guard for the performance of the second phase of the test.

Likewise, the guard returns to its closed position, if it has been moved during the first phase of the test. The state of the interlock is now sensed again to determine whether the interlock has changed or failed to change its state back to its safeguarding function required by its restored position. Corresponding test system output signals for the second phase of the test would indicate, inform and/or record whether the interlock has passed or failed this test. The second phase of the test need not be performed if the interlock has failed the first test phase.

Nevertheless, it may be desirable to perform the second phase test anyway, since it furnishes additional information about the interlock status.

If the test mechanism and/or its system suffer a failure which prevents their performing the interlock testing, such failure will be detected indirectly as an interlock failure during a scheduled interlock test, since the expected change of state signals from the interlock will not occur. Furthermore, by providing the test mechanisms with sensors, for instance limit switches, the malfunction of the test mechanism and/or its system can be detected and identified directly as such from the status of these sensors.

As stated previously, the testing system can provide for preventive locking of the guards during the test and/or in the event the interlock system fails the test. The locking devices utilized for this can be equipped with sensors whose status can inform the system of the locking status of the devices.

Applicant's invention is applicable to the remote and proximal testing of interlocks with all types of sensors, including mechanical, gravitational, electrical, electronic, magnetic, electromagnetic, light, infrared, ultraviolet, airflow, fluid, acoustic, intelligent sensors, etc.

Applicant's invention tests the physical interlock mechanism and its operating system to determine if the interlock system functions correctly or has failed.

Applicant's invention, furthermore, tests the interlock system in its operational position, its open or retracted position, and its restored or original guarding position.

Applicant's invention, in addition to detecting interlock failure, will also detect failure of the test mechanism and/or its system, indirectly as an interlock failure, when no failure detection sensors are built-in into the test mechanism and/or its system to detect such failure.

Applicant's invention, in addition to detecting interlock failure, will detect failure of the test mechanism and/or its system directly when failure detection sensors are built-in into the test mechanism and/or its system to detect such failure.

As part of applicant's invention, the interlocks protected barrier guards can be equipped with locking devices as part of the interlock testing system, and the locking devices can be equipped with sensors whose status can inform the system of the locking status of the devices, before, during, and after the test. A system for testing whether or not the guard is locked is covered later in this application.

In accordance with the present invention, there are various novel interlock testing constructions and systems illustrated and disclosed that enable the various interlocks to be manually or automatically tested. By the utilization of suitable timing devices, the testing can be done on a specified schedule or repeatedly, such as, every hour, daily, weekly, monthly, etc., as desired to insure that the interlocks are properly functioning. The frequency of testing is largely determined by various factors, such as possible failure rate, frequency of exposure of the hazardous space, location, etc. The aim is to assure with great reliability that if a guard is opened, there can be almost total confidence that the interlock will operate and turn off the machine so that personnel removing the guard and working in the guard protected space on the machine will not be at risk. Where the testing is done without shutting down the machinery, suitable precautions are provided to indicate when the interlock has been bypassed during the testing phase and, if desired, the guard may be locked into position during testing.

The locking mechanism may also be designed and controlled so that when the interlock is found to be inoperative or defective, the guard will remain locked and can only be opened by authorized personnel. In addition to, or in place of a lock, an indicator light or flag may be activated at the guard/interlock if it is found to be inoperative to warn of the unsafe condition.

Another feature of the automatic testing of the interlock system of the present invention is the detection of unauthorized bypassing of interlocks. Attempts to permanently or temporarily bypass an interlock will be noticed during the scheduled test phase following the bypass. The bypassed interlock would be identified and the guard can be placed on maintenance standby or locked against further use. When short test intervals are utilized, even unauthorized temporary bypassing of the interlocks is frustrated. Currently available bypass preventing interlocks do not rise to the capability of the present inventions.

It should be noted that the inventions allow fixed guards to be interlocked without the drawbacks associated with such dormant interlock systems that traditionally cannot be regularly tested. Because of the present inventions, the testing of interlocked fixed guards are now a practical possibility as discussed hereinafter.

The overall system is illustrated by example, schematically in FIG. 1. Examples of operating logic for a machine as it relates to remote testing of its interlocks, where the action of opening its barrier guards protected by interlocks turns the machine off, are illustrated in FIGS. 3-6.

While the present invention is primarily directed to the testing of interlocks and not to interlocks per se, it must be appreciated that there are certain features that must be included with existing interlocks in order to accomplish the testing functions. Thus, as aforementioned, a change of state of the interlock sensor has to be effected in order for the interlock to be tested. Thus, a part of the inventive interlock testing system requires that the interlocks be constructed and arranged so that testing thereof can take place. To this end, it is necessary to illustrate and describe relevant structural features that have to be incorporated with various interlocks in order to facilitate their testing. The illustrated examples are merely intended to be exemplary and not limiting. The essential ingredient is that the interlock be capable of being moved, breached or otherwise have its sensor state changed so that the interlock can be tested remotely or proximally with or without opening the guard or shutting down the machine as desired.

The testing procedure must be able to handle a wide variety of situations. This includes the guard being locked or stuck, springs not functioning to reposition sensor arms, sensing pins sticking, limit switches malfunctioning, etc. Essentially, the testing procedure is intended to include those eventualities likely to occur that will prevent the required operation of the interlock relative to the guard. This testing can be done in a mode to actually turn off the machine, or as aforementioned, the testing control system can include an automatic programming arrangement to bypass the interlock during its testing period while taking suitable precautions that personnel are aware that testing is occurring by an appropriate signal, such as a light or sound emitting device.

In the situations where it is desired not to shut the machine down when testing the interlock system, a control unit or other suitable mechanism will be used which will be programmed so that the interlock's power interrupt function and/or other relevant controls and functions will be temporarily bypassed for the duration of the test cycle while the interlock is quickly tested by changing the state of its sensor and then restoring its state to complete the test cycle. The control unit will indicate whether or not the interlock is functioning satisfactorily. In the event the interlock is not working, the machine can be automatically shut down and the interlock may be repaired or replaced, or the control unit may merely identify a bad interlock, on which a decision can be made how to proceed. If desired, the system can include the activation of a locking mechanism to lock the relevant guard closed and allow the machine to continue to operate until it is prudent or convenient to repair or replace the interlock.

Several of the aforementioned test system embodiments employ a limit switch or magnetic relay type interlock sensor and the movement of the limit switch or a change in the magnetic field is registered by the controller after the switch or relay has been moved relative to a guard. In one embodiment (FIG. 7), a movable outwardly biased plunger can be employed to slightly move the guard to a position where it will allow the interlock switch or relay sensor to be tested to see if it would function to turn off the machine. If the guard is locked or stuck in position (FIG. 8), the switch or relay is moved away from a guard to permit testing of the interlock switch or relay.

To facilitate movement of the interlock assembly relative to a guard, the interlock control means such as a relay or limit switch sensor is affixed to a resilient mount on the machine frame or guard to enable the relay or limit switch to move relative to the machine frame or guard (FIGS. 7 and 8). A resilient mount deforms under the influence of an external force and restores essentially or completely its shape after the deforming force is removed from it. Movement of the interlock control means is accomplished by a motorized screw or solenoid plunger placed in engagement with the guard (FIGS. 7 and 8). Thus, if the guard is free to open, the motorized screw moves the guard to the slightly open position and the interlock control means will then be free to move and signal if it is or is not working properly to a program unit and/or some type of suitable indicator, such as a sound or light device. In the event the guard is fixed in position, the motorized screw will engage the guard and will force the interlock mechanism and switch backwards away from the guard as permitted by the resilient mount design. The movement or lack of movement of the interlock sensor will be indicated on the program unit.

In the event a magnetic interlock is used (FIG. 9), it will be operated in the same fashion, only in this case the resilient mount will be mounted on the guard (FIG. 9), and a magnet will be pushed away to open the gap and thus change the existing magnetic field and indicate whether or not the magnetic interlock is properly functioning.

Applicant's novel test system also works very effectively with an interlock that uses a toggle mechanism operated by a solenoid (FIG. 10) that will initially move the guard to the open position if it is free to be opened or will result in the interlock limit switch being moved backwards relative to the fixed guard which in this case is biased toward the guard by a spring mechanism. Spacing the interlock from the guard, tests the interlock to see if it is properly functioning. The interlock control means is located on rollers to permit it to move against the action of the biasing spring.

Another modified interlock arrangement (FIG. 11) that can be used in a test system involves the use of flat springs to which a roller interlock mechanism and pusher unit is connected to permit resilient movement of the roller interlock and pusher unit away from the guard to facilitate testing in the event the guard is stuck. If the guard opens in response to movement by the plunger member of the pusher unit, the resilient mounting arrangement need not come into play.

Another illustrated type of interlock embodiment to be used in a test system (FIGS. 12 and 13) is an interlock that employs a linear actuator that is affixed to a machine base and has connected to its actuator shaft a test arm that is secured to an interlock sensor including a sensor arm. In this arrangement, the linear actuator would be activated to move the interlock sensor away from the guard and in such position the integrity of the interlock is tested by sensing whether or not the sensor arm is functioning properly to shut off the machine. All of the aforementioned modified interlock embodiments to be used in a testing system were by way of illustration applied to interlock sensors that require positive movement by a sensor arm and if such movement does not occur, a program unit indicates that the interlock was not functioning correctly. As can be appreciated, while these interlock devices are relatively simple in design, they have the disadvantage that if the guard is opened and the sensor does not function properly the machine will not stop running, which may present a safety hazard.

Other types of illustrated interlock designs that can be tested using applicant's novel system include an actuator where the interlock is moved to mimic its operational behavior by positively moving the sensor arm, as illustrated in FIGS. 14 and 15, or moving the sensor arm against a spring force (FIG. 16) to a position that turns the machine off when the interlock system functions properly. In these embodiments, when the test system is in the testing mode, the linear actuator in FIGS. 14 and 15 and the solenoid unit in FIG. 16 are the test mechanisms which move the interlock sensor into the retracted and extended positions and test the interlock system for proper function in both sensor positions.

There are two other illustrated designs which essentially permit testing by manual movement of either a resiliently biased plunger or the opening of a guard a limited amount (FIGS. 17 and 18). In the case of the plunger (FIG. 17), it is operated to pull a blocking member away from a limit switch interlocking mechanism to allow the switch to extend automatically to turn off the machine if it is functioning properly. A suitable signal would be provided so that when the button is pulled and the switch did not move to turn off the machine it would indicate that the interlock was not working.

Another way of testing interlocks (FIG. 18) without requiring full opening of a guard that would permit access to a hazardous space is to provide guards with limited restrictive movement which movement would be only enough to allow an interlock to have its integrity tested by permitting the sensor to move into the provided space or tested by the automatic means illustrated in FIG. 7. In this embodiment, there is also illustrated an arrangement whereby a locking mechanism is provided in conjunction with the limited movement control so that in the event the interlock is tested and does not function properly, the arrangement restricting the movement of the guard will remain in place to prevent the guard from being fully opened. The movement control mechanism will be designed so that the guard can then be opened only by a supervisor.

It can be appreciated that most, if not all, of the interlock mechanisms can be used in conjunction with a suitably provided device to lock the guard closed during testing and/or preventively lock the guard if the test has detected that the interlock is malfunctioning.

It is a simple matter, as illustrated in the logic flow diagrams of FIGS. 3-5, to include in the interlock test system circuitry control means for operating a lock to prevent a guard from being opened. As indicated previously, such locking devices can be equipped with sensors whose status can inform the system of the locking status of the device before, during and after the interlock test.

An example of a mechanism that will function to positively lock a guard in position during testing is illustrated in FIGS. 20-22.

Another novel testing procedure that is an important aspect of the applicants invention is the ability to test interlocks of guards that are equipped with integral interlock- lock devices and which in a typical situation, when the guard is closed, will have the lock latched to the guard.

The integral interlock-lock is typically a device which houses both the interlock and the guard lock in a combined housing. The mechanical testing of the interlock for such a coupled device requires the unlatching of its lock from the guard before the interlock testing can be executed.

In this testing system before the interlock of a particular integral interlock-lock device is tested, the interlock function and the lock function is bypassed so that testing of the interlock and lock will not result in shutting down the machine. In this system a program controller will be activated to show that the testing process is to begin. This particular system will include a mechanism for unlatching the lock and if the lock unlatches by changing its state the change of state is indicated on the controller. If the lock did not unlatch then of course the interlock can not be tested and suitable indication will be made to show that the lock did not unlatch. In this particular situation if it is not desired to shut the machine down the controller will indicate that the guard latching system has to be repaired or replaced. The bypass functions will then be removed to reinstate the protection afforded by the interlock and lock.

Returning to the situation in which the lock did unlatch, the interlock tester will then be activated to move the interlock to its"guard open"position. Various types of interlock testers and testing systems that would be acceptable in the instant system are discussed this application. The details of the interlocks are not important to an understanding of the systems hereinafter detailed except to note the following features of faultless interlocks.

When an interlock is moved relative to the guard closure it protects, or vice versa, the interlock's sensing mechanisms changes state. When the interlock and guard closure are brought back together the interlock sensing system returns to its original state. The testing of the interlock is done by producing these relative displacements and determining if the required changes of state happen.

If the interlock fails to change its state to the"guard open"state by this test it will be recorded that the interlock failed the test and if it did change state the fact that the interlock passed the test will be recorded.

Since this system is used to test the interlock the interlock tester will as the next step restore the interlock to its"guard closed"position and will check if it has thereby returned to its"guard closed"state. If it failed to return to the"guard closed"state, recording of this will be made and if it did return the fact that the interlock passed the test will be so indicated.

Following the aforementioned test the lock will be relatched and the system will be tested to check if the lock did relatch which would be to change its state back to what it was originally.

If it did not return to its original state a recording to the effect that the lock failed to relatch will be made and if it did return the controller would indicate that the lock did relatch. Upon indicating that the lock relatched the bypassing of the lock in the system will be removed to restore its original protection. If the interlock passed all the tests this will be recorded, the interlock function will be restored by removing its bypass to restore its original protection and the program controller will sequentially test the interlocks of other integral integral-lock devices. If the interlock did not pass the tests the"test failed"warning indicators and devices will be activated and the machine may be shut down due to test failures and be repaired at that time, or not be shut down and just indicate what has occurred and continue to test other interlock-lock systems until the last one is tested at which time the program controller will be deactivated.

The present invention also includes a novel system (figure 25) comprising a guard closure test routine in which the closures are also protected by interlocks but wherein the locks and interlocks are not integral devices and the interlock is used to make a redundant closure test check. In this testing system one will first select a guard closure to be tested and reset the test routines to their test initiation states in which the guard closure locks are latched.

Initially the interlock mechanisms are bypassed so that the testing of the guards will not shut down the machine in the event that the guard moves to the open position when a guard testing device such as a probe is used to attempt to open the guard closure. In addition to bypassing the interlocks"guard closure test on"indicators and devices are activated. As discussed in the earlier embodiment referred to as the first novel system the guard closure is tested by deploying a tester probe against the guard closure, and a program controller will indicate if the probe actually did deploy. If the probe did not deploy the test of this particular closure is terminated and the interlock function will be reinstated so that in the event the closure is opened the interlock will function normally, to turn off the machine.

A recording of the inactivity of the probe will be made and a suitable indicator will show that the guard cannot be tested and that necessary repair and/or replacement is required. If the probe did deploy then the amount of probe movement will indicate if the guard closure is closed, open or can be opened. An indication that the guard closure is in an open or opening condition will be recorded indicating that there is a problem with respect to the particular guard in question. If the guard closure is not opened this will be noted and if the interlock is known not to be faulty then the interlock will be used to make a redundant test check of the closure status. A known to be faulty interlock or one of unknown condition will not be used to make a closure test check. If it is indicated by the interlock that the guard is in the open position then the fact that the guard closure did fail the interlock test will be signaled.

As the next test step, the closure tester probe is retracted and a test conducted to see if the probe did retract. Failure to retract will be recorded and replacement and/or repair will be scheduled. If the closure and probe passed all the tests the"test passed"indicators and devices will so indicate and the interlock function will be reinstated by removing the bypass to restore its original protection. Any failures will activate"test failed warning indicators and devices"and shut down the machine or not as desired and then move on to test another subsequent guard closure following the same method as herein aforesaid. Another method of testing of allegedly locked guard closures which are also protected by interlocks can be done by a novel system (figures 26a and 26b) calling for a sequential testing first of the interlock and then the closure. In this embodiment the test initiation states of the interlocks and guard closure test routines are reset and the appropriate indicators and devices are activated showing that the interlock and guard closure tests are being done. Also the interlock function is bypassed so that if the guard is opened by the guard closure test the interlock will not shut down the machine. The testing of the interlock will then be accomplished by changing the interlock to the"guard open"position and then making the appropriate tests and records. If the interlock passes or fails the test this will be recorded and indicated. The interlock will then be restored by its tester to the"guard closed"position and checked if it has so returned. If it failed to return to the"guard closed"state, recording of this will be made and if it did return the fact that the interlock passed the test will be recorded. Following the testing of the interlock the guard closure is tested in the same manner as set forth when discussing the novel system comprising a guard closure test routine protected by separate interlocks (FIG. 25).

Another system that could be employed is one that includes sequential testing of the interlock and then the closure where the allegedly locked closures are protected by an integral interlock-locking device.

Another testing system (figures 27a and 27b) includes a program controller that is initially programmed to bypass the interlock and lock function and activate the"tests on" indicators and devices and includes a locked guard closure. The interlock is tested by first unlatching the lock and testing if the unlatching did or did not occur. If it did not occur a record will be made of this and that the interlock cannot be tested. The interlock will not be used to make a redundant closure test check since the interlock was not tested.

In the event the lock did unlatch by changing its state this system will test the interlock of the integral interlock-lock arrangement, as set forth above. Following the testing of the interlock, the guard closure will be tested by using a test device such as a probe is used with respect to a guard and its action tested and the interlock will be used to make a redundant closure test check if the interlock has been tested and if it had not failed the interlock tests.

This last mentioned system slightly differs from the previous system since while the closure test probe may not deploy, which is a failure of the closure tester, and will be so recorded and indicated, the integral interlock-lock may pass all tests and thus provision is made to reinstate the interlock function by removing the interlock and lock bypass to restore their protective functions and activate the"tests passed"indicators and devices. For all tests which did not pass, the"tests failed"warning indicators and devices will be activated and the program controller will so indicate, and a choice can be made to shut down the machine or allow the machine to operate while indicating what has occurred.

Another system (figure 28) forming part of applicants invention is a routine for testing allegedly locked closures protected by interlocks where there is a simultaneous testing of both the closure and the interlock with the same tester. The tester is so constructed that it performs the tasks of testing the guard closure and the interlock by the same action. In this system the interlock and/or tester is compliant base mounted as described in detail in the aforementioned pending application that is incorporated herein by reference, but the tester and interlock are rigidly linked together. Prior to starting, one will select the interlock/guard closure to be tested and will reset their test routines to their test initiation states. Initially one will activate the"interlock/guard closure tests on"indicators and devices and bypass the interlock function and then test the guard closure and the interlock by deploying the tester probe to the guard closure and testing the closure and interlock. The steps of the test procedure and the action of the tester and its probe are best understood by reference to the descriptions of the flow chart in figure 28 and an exemplary mechanism in figures 33-36.

In this system, if the probe does not deploy then the guard and interlock cannot be tested, therefore the interlock function will be reinstated by removing the bypass to restore its protective function and the necessary repair and/or replacement will be scheduled. If the probe does deploy and the guard closure is open or has opened as determined by the amount of probe movement, record that the guard closure failed the probe test; if it did not open record that the guard closure passed the probe test. The program controller will then test to see if the interlock changed to the"guard open"state due to the action of the tester probe and record if the interlock passed or failed this test and record the outcome. The tester probe is then retracted and if the probe did or did not retract will be ascertained and it will be recorded and indicated whether the interlock passed or failed the retraction test. If the guard closure, interlock and probe passed all the tests the interlock function will be reinstated by removing its bypass to restore its protective functions and the"test passed"indicators will be activated. If all tests did not pass the controller will activate the"tests failed"warning indicators and devices and shut down the machine or not as desired. If the machine is shut down the interlock function will be reinstated to restore its protective function and the"tests on" indicators deactivated. If it is elected to not shut down the machine the interlock will remain in the bypass mode and allow the machine to continue to operate and to schedule the necessary repair or replacement for a future time.

It remains to note that the novel systems illustrated and disclosed herein are employed as part of a main routine (figure 29) that controls the running of a machine and also directs the testing of its guard closures and interlocks. The testing in question is done without shutting down the machine. This main routine is similar to that described in figure 3 for testing interlocks.

BRIEF DESCRIPTION OF THE DRAWINGS In the following drawings there will be a number of illustrations setting forth the novel testing system for closures and closures with interlocks employing various types and designs of interlock arrangements.

FIG. 1 is a schematic view of an automatic guard closure interlock testing system; FIG. 2 is a flow diagram of a subroutine for testing closures not protected by interlocks; FIG. 3 is a flow diagram of a main routine for testing interlocks; FIG. 4 is a subroutine of the main routine of FIG. 3 to carry out testing of the interlocks ; FIG. 5 is another subroutine of the main routine of FIG. 3 to carry out testing of interlocks; FIG. 6 is another subroutine of the main routine of FIG. 3 to carry out testing of interlocks; FIGS. 7-20 illustrate various types of interlocks including various features which permit them to be tested either remotely or proximally wherein FIG. 7 shows a resiliently mounted interlock opening a guard during testing; FIG. 8 is a view similar to FIG. 7 in which the interlock has been moved relative to a guard so it can be tested when the guard is in a locked or stuck position; FIG. 9 discloses a magnetic sensor interlock including a test device acting against a resilient mount to facilitate testing thereof ; FIG. 10 illustrates a modified interlock mechanism that uses as the test mechanism a toggle mechanism operated by a solenoid to move a plunger, which interlock is free to move on rollers so it can be tested; FIG. 11 is another embodiment in which the interlock test mechanism employs a plunger that is mounted relative to a fixed base by flat springs to permit movement relative to the guard if the guard cannot be opened so the interlock can be tested; FIG. 12 is an interlock arrangement in which an actuator can be operated to move an interlock sensor unit away from the guard to where it can be tested to determine whether the interlock is properly functioning; FIG. 13 is a view similar to FIG. 12 showing the interlock sensor unit removed from the guard by the actuator; FIG. 14 is an interlock test embodiment using an actuator to move a sensor pin relative to its housing to determine if it is in proper working order; FIG. 14A shows the sensor pin in position when the guard is open; FIG. 15 is a view showing the interlock of FIG. 14 in the testing position; FIG. 16 discloses a solenoid relay type test mechanism acting on an interlock which is of the normally closed held open type that functions by moving the actuator and does not require that the guard or interlock body be moved; FIG. 17 discloses a manually operated plunger which when moved relative to a guard permits testing of the interlock; FIG. 18 is a view showing a hinged guard having a limited movement to permit manual or automatic testing of an interlock caused by the limited movement of the guard and which also includes a mechanism that limits and controls the movement during testing and can be used to afterwards preclude full opening of the guard in the event the interlock fails during testing ; FIG. 19 is a view illustrating a light curtain guard system; FIG. 20 is a side view of the light curtain illustrated in FIG. 19 and a probe for intercepting the curtain to test the system; FIG. 21 is a side view of a linear actuator testing mechanism with a mechanically linked barrier guard locking device; FIG. 22 is a perspective view of the apparatus of FIG. 21 showing the lock disengaged from the barrier guard; and FIG. 23 is a view similar to FIG. 22 with the lock in engagement with the barrier guard.

FIG. 24 is a flow diagram of a subroutine for testing interlocks of guards equipped with integral interlock-lock devices; FIG. 25 is a flow diagram of a guard closure test subroutine for closures protected by interlocks; FIGS. 26a and 26b is a flow diagram of a subroutine for the sequential testing of interlocks and closures; FIGS. 27a and 27b is a flow diagram of a subroutine for the sequential testing of interlocks and closures including an integral interlock-locking device; FIG. 28 is a flow diagram of a subroutine for the simultaneously testing of both the closure and an interlock with the same tester; FIG. 29 is an example of a main routine for testing interlocks and guard closures; FIGS. 30-32 illustrate various positions of an embodiment including an assembly for testing a guard closure normally locked in position; FIGS. 33-36 illustrate various positions of a second embodiment for testing a guard closure and an interlock in which the closure tester is connected to a interlock assembly that is in turn secured to a complaint base.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is illustrated a schematic view of a testing system 10 for a plurality of interlocks 12a, 12b, 12c... 12n mounted in various locations on an operating machine. The interlocks are provided to shut down the machine 11 when the space protected by any given interlock is exposed to permit access to working personnel. The interlocks are monitored by a control unit 14 which is programmed to respond to the action of each interlock when testing is to occur. The control unit 14 can selectively bypass the machine 11 shutdown function of each interlock if so desired at any selected interval determined by, for example, a timer, to permit testing of the interlock without shutting the machine 11 down. After an interlock is bypassed, it will be tested and the control unit 14 will indicate if the interlock is functioning properly. During the testing, suitable signaling devices (not shown) can be provided at desired locations, for instance, adjacent to each guard and the machine 11 operating stations, to indicate that the interlock has been bypassed so that a guard will not be inadvertently opened and personnel exposed to injury.

As shown in FIG. 1, the testing system 10 preferably includes one or more machines 11 (one being shown), a control unit 14, an input device 16, and an output device 17. The system 10 may also include one or more detection units 18 (one being shown), such as, for example, flow sensors, proximity sensors, heat detecting devices, to detect certain operating conditions of the system 10. The detection units 18 of the system 10 may communicate with the control unit 14 by transmission line 19 or any other suitable communication link. It will be recognized that the control unit 14, the input device 16, and output device 17 may be integral with the machine 11 or remote from the machine 11.

The machine 11 preferably includes one or more interlocks 12a, 12b, 12c... 12n and guards 15. Each of the interlocks 12a, 12b, 12c... 12n has a switch and may be in communication with or coupled to the control unit 14 by transmission lines 13a, 13b, 13 c... 13 n, respectively. The transmission lines may be one-way or bi-directional communication links of any suitable type.

An integral locking mechanism L or a separate locking device S schematically shown mounted on each guard in FIG. 1 can be provided, if desired, to lock out a guard when the interlock therefor is being tested. Additionally, the locks can be configured and controlled to keep a guard locked if its interlock fails the test (see FIGS. 4-5). If the interlock has been bypassed to perform the test, the bypass can be maintained and the guard locked until the interlock is to be repaired or replaced during routine or specifically scheduled maintenance, thereby avoiding disruptions of scheduled machine operations for such repair or replacements.

The control unit can be set to test the interlocks on any specified schedule, for instance, during each shift, hourly, daily, weekly, or any other interval. A signal or light, such as a light or flag, can be placed wherever desired, for instance, adjacent to each guard, and be suitably activated in the event the interlock fails, to warn personnel of this condition. Similarly, while interlocks are shown in conjunction with guard closures a number of closures may not be protected by interlocks. Thus the testing system is not intended to limit the application of applicants invention and is merely intended to provide a general overview of systems that can be employed.

In FIG. 1, the input device 16 of the system 10 is in communication with or coupled to the control unit 14. The input device 16 may include a keyboard, a keypad, or any other suitable input device 16. The input device 16 may allow a number of versatile control or scanning functions to be utilized. For example, the interlocks may be continuously monitored or checked at a preselected time. Alternatively, the frequency and duration of monitoring all or a selected number of interlocks may be initially preset and/or changed.

The output device 17 of the system 10 is also in communication with or coupled to the control unit 14. The output device 17 may generate a message or an alarm that can be visual, audio, or whatever else is suitable, singly or in combination, when a malfunctioning interlock is detected. The output device 18 may include a display or a monitoring panel that may alert an operator that a trouble or an alarm condition exists and may also indicate the location of the malfunctioning interlock in the environment.

The output device 17 may further display a message to identify the corrective action required. The output device 17 may be designed at any level of sophistication or complexity in order to process the information about the status of the interlocks and to indicate that a problem exists with one or more interlocks.

The control unit 14 of the system 10 checks the functioning or operation of one or more interlocks as well as other machine controls. The control unit 14 may include, for example, a program unit, a processing unit, a computer, a programmable logic controller, a microprocessor, etc. The control unit 14 can be commanded with any suitable operating system, and can be digital, analog, hardwired, etc., or combinations of these. The control unit 14 can be commanded to continuously monitor the interlocks and test them in any sequence combination at a preselected schedule, frequency, duration, or randomly.

When the control unit 14 detects a malfunctioning interlock, a light and/or any other suitable alarms may be activated at the output device 17 and/or near the interlock, and the control unit 14 may place the interlock in a maintenance standby mode as further described below. A message indicating a malfunctioning interlock may also be displayed on the output device 18. The particular location of the interlock of the machine 11 may further be identified.

In figure 2 there is shown a subroutine to test a guard closure that is not protected by interlocks. The subroutine is designated by the number 20 and is started by selecting a guard closure to be tested wherein the memory location storing the test states of the closure is reset at 20A. At 20B the guard closure"test on"indicators and devices are activated. To test the position of the guard closure a tester probe is applied to the guard closure at 20C and at 20D a determination is made whether the probe deployed, and if it deploys does it open the guard closure or indicates that the guard closure is open at 20E. If the probe did not deploy it will be so recorded at 20F. At 20G the indicators will show that the probe did not deploy and the guard cannot be tested and the necessary repair and/or replacement will be scheduled 20H.

Returning now to the indicator 20E where if the guard closure opened or is open then at 20J it will be recorded that the guard closure failed the test. If the guard did not open then at 20I it is recorded that the guard closure passed the test. Following the test the closure tester probe is commanded to retract from the closure at 20K. From there it will be determined at 20L if the probe retracted, and if it retracted it will be determined at 20M whether the closure and probe passed all the tests. If the probe did not retract this will be recorded at 20N and at 20P indicators will show that the probe did not retract. At 20Q the necessary tester repairing and/or replacement will be scheduled. Returning now to 20M wherein it is determined if the closure and probe did or did not pass all the tests there are two possible results. If they did not pass all the tests, the test failed warning indicating devices are activated at 20R and at 20S it will be determined whether the machine is to be shut down or not due to the test failures. If yes, the machine is shut down at 20T and if the machine is not to be shut down at 20U the necessary repair and/or replacements are scheduled. If the machine is shut down the guard closure test indicator devices will be deactivated at 20V after which there is a return to the main routine shown in figure 29. The main routine is described in detail hereinafter. If the path is from 20U to 20W and if it is the last guard closure to be tested as indicated at 20W the system is then deactivated at 20X and returns to the main routine but if not the testing process will be started over again at a new guard closure. If the closure and probe passed all the tests it will be indicated at 20Y.

FIGS. 3-6 illustrate an interlock test routine executed by the control unit 14 to test one or more interlocks to determine whether the interlocks are functioning properly. If one or more of the interlocks is malfunctioning, the machine 11 may be shut down or the malfunctioning interlock may be placed on maintenance standby mode. The interlock test routine may be implemented by conventional hardware components and circuit designs, computer programming, and combinations thereof. Exemplary flow chart diagrams are described below, but it is understood that these are for the purposes of illustration only, and the flow chart diagrams may utilize any suitable implementation that will carry out the function of the process.

FIG. 3 illustrates a main routine 22 of the interlock test routine to test interlocks of a machine 11 of FIG. 1 in which the action of opening a barrier guard protected by an interlock turns the machine 11 off. It will be recognized that the main routine may test interlocks by sensing a change of state of the interlock (e. g., a change of an electrical parameter associated with the interlock). The control unit 14 of the machine 11 system may process all inputs and outputs, monitor all switches, and determine whether the machine 11 is operating properly. The main disconnect may be opened or closed at block 22A and the emergency stop controls may be manually activated or deactivated at block 22B. It is also contemplated that the main disconnect and emergency stop controls may be automatically controlled.

Initially, the control unit 14 determines whether the main disconnect of the machine 11 is closed at block 22C. If the main disconnect is not closed, the control unit 14 turns the machine 11 off at block 22D, bypasses the control center, and ends the interlock test routine. If the main disconnect is closed, the control unit 14 determines whether emergency stop controls, such as, for example, shutdown switches, are activated at block 22E. If the emergency stop controls are activated, the machine 11 is turned off at block 22D. If the emergency stop controls are not activated, the control unit 14 determines whether the input and output controls (I/O controls) of the machine are enabled at block 22F. If the (I/O controls) are not enabled, the control unit 14 enables the I/O controls of the machine 11 at block 22G to permit the machine 11 to operate for its intended function and the control unit proceeds to block 22H as further described below.

If the I/O controls are enabled at block 22F, the control unit determines whether the machine controls other than the interlocks are satisfied, such as, for example, heat sensor, proximity sensors, etc. If the machine controls are not satisfied, the machine is shut off at block 22I and the process returns to the control unit 14. If the machine controls are satisfied, the control unit determines whether the interlock sensor states are satisfied at block 22J. If the interlock sensor states are satisfied, the control unit determines whether an interlock test is in progress at block 22K. If the interlock sensor states are not satisfied at block 22J, the control unit determines whether the interlock bypass is enabled at 22L. If the interlock bypass is not enabled, the machine is shut off at block 22I and the process returns to the control unit 14. If the interlock bypass is enabled at block 22L, the control unit 14 determines whether an interlock test is in progress at block 22K.

If an interlock test is in progress at block 22K, the routine returns to the machine system control unit 14. If no interlock tests are in progress, the control unit 14 determines whether the machine is running at block 22M. If the machine is running, the control unit 14 determines whether to initiate and conduct an interlock test at block 22N as further described below. If the machine is not running at block 22M, the control unit 14 determines whether to start the machine at block 22P. If the machine is not to be started, the machine is turned off at block 22I and the process returns to the control unit 14. If the machine is to be started at block 22P, the control unit 14 will start the machine and then determine whether the machine is running at block 22Q. If the machine is not running, the routine returns to the control unit via block 22I. If the machine is running, the process proceeds to block 22N.

At block 22N, the control unit 14 determines whether to initiate and conduct an interlock test. If an interlock test is not to be initiated, the process returns to the machine system control unit 14. If the interlock test is to be initiated, the control unit 14 will initiate an interlock test sub-routine at block 22R, and in parallel with this initiation the process returns to the control unit 14 at block 22S for the next pass through the main routine. When the block 22R completes its interlock test sequence described below, it too returns the process to the control unit 14.

Preferably, three different sub-routines may be executed to test the interlocks.

The sub-routines include a first sub-routine 24 (FIG. 4) to test interlocks having a separate guard locking device S (see FIG. 18), a second sub-routine 26 (FIG. 5) to test interlocks having an integral guard locking device L (see FIGS. 21-23), and a third sub-routine 28 (FIG.

6) to test interlocks without a guard locking device utilized for the interlock testing.

The first sub-routine 24 of the interlock test routine is illustrated in FIG. 4 and includes the capability of bypassing the barrier guard interlock function of the machine 11 so that the machine 11 will not shut down when the interlock is tested. The first sub-routine 24 will also activate separate locking devices to lock the barrier guard. When the first sub- routine 24 is initiated, the memory location storing the test states of the interlock is reset at block 24A. It will be recognized that the memory location for a single interlock may be reset or the memory location for all interlocks may be reset. Next, the barrier guard of the machine 11 is locked at block 24B and"interlock test on"indicators and devices are activated at block 24C. The indicators and devices may be located near the interlock, at the output device of the system, or both. The interlock function is also bypassed at block 24D so that the machine 11 will not be shut down when testing the interlock.

At block 24E, the interlock is retracted from the barrier guard by the test system and/or the barrier guard is moved or breached by the test system to perform the interlock test. The interlock is then tested a first time to determine whether the interlock has changed state as required. The control unit 14 then determines at block 24F whether the interlock passed the first test. If the interlock passed the test, the results of the test are recorded at a selected memory location associated with the interlock at block 24H and the process proceeds to block 24I. If the interlock failed the test, the results of the test are recorded at a selected memory location associated with the interlock at block 24G and the control unit determines whether to perform the original position test at block 24J. If the original position of the interlock is not to be tested because the interlock has already failed the first test, the"test failed"warning indicators and devices are activated at block 24K and the process proceeds to block 24L as further described below. The"test failed"indicators and devices may be located where desired, for instance, at the output device, near the interlock, or both. If the original position test is to be performed, the process proceeds to block 24I. Thus, while the failure of the interlock to pass the test when retracted from the barrier will be recorded, the interlock may also be tested, if desired, to see if it is operative when in its original position. This situation applies with respect to the sub-routines FIGS. 5 and 6 as well.

At block 24I, the interlock is moved after the completion of the first test by the test system to its original safeguarding position, and the barrier guard also returns to its original safeguarding position if it has been moved or breached to perform the first test. The interlock is then tested a second time to determine whether the interlock has returned to its original safeguarding state. At block 24M, the control unit 14 determines whether the interlock passed this second test. If the interlock failed the test, the results are recorded at a selected memory location associated with the interlock at block 24N. If the interlock passed the test, the results are recorded at a selected memory location associated with the interlock at block 24P.

The control unit 14 then determines at block 24Q whether the interlock passed all the tests. If the interlock did not pass all of the tests, the"test failed"warning indicators and devices are activated at block 24K. The interlock is then placed in maintenance standby at block 24L. As a result, the barrier guard remains locked and can only be opened by authorized personnel so that the interlock may be repaired or replaced. The interlock function remains in a bypass mode to allow the machine 11 to operate but the bypass can be removed by authorized personnel for interlock maintenance or other reasons. The control unit 14 then proceeds to block 24S as further described below.

If the interlock passed all of the tests at block 24P, the interlock function is reinstated (i. e., remove bypass) at block 24T so that the machine 11 will shut off when the barrier guard is breached."Test passed"indicators and devices are also activated at block 24U, and the barrier guard is unlocked at block 24V. The process then proceeds to block 24S.

At block 24S, the control unit 14 then determines whether the last interlock has been tested. If another interlock needs to be tested, the control unit 14 will test the next interlock beginning at block 24A. If all of the interlocks have been tested, the"interlock test on"indicators and devices are deactivated at block 24W. The control unit 14 then returns the process to the main routine 22 at block 22R.

The second sub-routine 26 of the interlock test routine is schematically illustrated in FIG. 5 and includes the capability of bypassing the barrier guard interlock function of the machine 11 so that the machine 11 will not shut down when the interlock is tested. The second sub-routine 26 will also activate a barrier guard locking mechanism integral with the interlock testing device. For example, when the interlock is retracted from the barrier guard, a mechanical link automatically locks the barrier guard, and when the interlock is returned to its original position, the barrier guard is automatically unlocked. (See detailed description hereinafter with respect to FIGS. 21-23.) When the second sub-routine 26 is executed, the memory location storing the test states of the interlock is reset at block 26A. It will be recognized that the memory location of a single interlock may be reset or the memory locations for all of the interlocks may be reset."Interlock test on"indicators and devices are then activated at block 26B. The interlock function is also bypassed at block 26C so the machine 11 will not be shut down when testing the interlock.

At block 26D, the interlock is retracted from the barrier guard by the test system and/or the barrier guard is moved or breached by the test system to perform the interlock test. The barrier guard is automatically locked by the integral locking device. The interlock is then tested a first time to determine whether the interlock has changed state as required. The control unit 14 then determines at block 26E whether the interlock passed the first test. If the interlock passed the test, the results of the test are recorded at a selected memory location associated with the interlock at block 26G and the process proceeds to block 26H. If the interlock failed the test, the results of the first test are recorded at a selected memory location associated with the interlock at block 26F and the control unit determines whether to perform the original position test at block 26J. If the original position test is not to be performed,"test failed"warning indicators and devices are activated at block 26K and the process proceeds to block 26L. If the original position test is to be performed, the process proceeds to block 26H.

At block 26H, the interlock is moved at the completion of the first test by the test system to its original safeguarding position, and the barrier guard also returns to its original safeguarding position if it has been moved or breached to perform the first test. These actions also unlock the barrier guard because of the nature of the integral locking device design. The interlock is then tested a second time to determine whether the interlock has returned to its original safeguarding state. The control unit 14 then determines at block 26M whether the interlock passed this second test. If the interlock failed the test, the results are recorded at a selected memory location associated with the interlock at block 26N and the process proceeds to block 26P. If the interlock passed the test, the results are recorded at a memory location associated with the interlock at block 26Q. The control unit 14 then determines at block 26R whether the interlock passed all of the tests. If the interlock did not pass all of the tests, the process proceeds to block 26P.

At block 26P, the locking mechanism is reactivated to a locking position and the"test failed"warning indicators and devices are activated at block 26K. The interlock is then placed on maintenance standby at block 26L. As a result, the barrier guard remains locked and can only be opened by authorized personnel so that the interlock can be repaired or replaced. The interlock function remains in bypass mode to allow the machine 11 to operate but the bypass can be removed by authorized personnel for interlock maintenance or other reasons. The process then proceeds to block 26S.

If the interlock passed all of the tests at block 26R, the interlock function is reinstated (i. e., remove bypass) at block 26T so the machine 11 will shut off when the barrier guard is breached. The"test passed"indicators and devices are also activated at block 26U.

The process then proceeds to block 26S.

At block 26S, the control unit determines whether the last interlock has been tested. If the last interlock has not been tested, the control unit 14 then tests the next interlock beginning at block 26A. If the last interlock has been tested, the"interlock test on"indicators and devices are deactivated at block 26V. The control unit 14 then returns the process to the main routine 22 at block 22R.

The third sub-routine 28 of the interlock test routine illustrated in FIG. 6 includes the capability of bypassing the barrier guard interlock function of the machine 11 so that the machine 11 will not shut down when the interlock is tested, but does not activate a barrier guard locking device. When sub-routine 28 is initiated, the memory location storing the test states of the interlock is reset at block 28A. It will be recognized that a memory location for a single interlock may be reset or the memory locations of all of the interlocks may be initially reset.

At block 28B,"interlock test on"indicators are activated. The interlock function is also bypassed at block 28C so that the machine 11 will not shut down when testing the interlock. At block 28D, the interlock is then retracted from the barrier guard by the test system and/or the barrier guard is moved or breached by the test system to perform the interlock test. The interlock is then tested a first time to determine whether the interlock has changed states as required. The control unit 14 then determines at block 28E whether the interlock passed the first test. If the interlock passed the test, the results are recorded at a selected memory location associated with the interlock at block 28G and the process proceeds to block 28H. If the interlock failed the test, the results are recorded at a selected memory location associated with the interlock at block 28F and the control unit 14 determines whether to perform the original position test at block. If the original position test is not performed, "test failed"warning indicators and devices are activated at block 28J and the process proceeds to 28K as further described below. If the original position test is to be performed, the process proceeds to block 28H.

At block 28H, the interlock is returned after completion of the first test by the test system to its original safeguarding position, and the barrier guard also returns to its original safeguarding position if it has been moved or breached to perform the first test. The interlock is then tested a second time to sense whether the interlock has returned to its original safeguarding state. The control unit 14 determines at block 28L whether the interlock passed this second test. If the interlock failed the second test, the results are recorded at a memory location associated with the interlock at block 28M and the process proceeds to block 28P. If the interlock passed the test, the results are recorded at a memory location associated with the interlock at block 28N and the process proceeds to block 28P.

At block 28P, the control unit 14 then determines whether the interlock passed all of the tests. If the interlock did not pass all of the tests, the"test failed"warning indicators and devices are activated at block 28J and the control unit determines whether to turn the machine off at block 28K. If the machine 11 is not to be turned off, then the interlock is placed on maintenance standby at block 28Q. The interlock function remains in a bypass mode to allow the machine 11 to operate, but the interlock provides no safety to the guarded space if the barrier guard has not been previously locked, or if locked, can be opened without safety authorization. The bypass can be removed by authorized personnel for interlock maintenance or other reasons. The process then proceeds to block 28R as further described below.

If the machine 11 is to be turned off per instruction of block 28K, the interlock function is reinstated (i. e., remove bypass) at block 28T, the"interlock test on"indicators and devices are deactivated at block 28U and the sub-routine 28 returns to location M of the main routine 22.

If the interlock passed all of the tests at block 28P, the interlock function is reinstated (i. e., remove bypass) at block 28V so the machine 11 will shut down when the barrier guard is breached. The"test passed"indicators and devices are also activated at block 28W. The process then proceeds to block 28R.

At block 28R, the control unit 14 determines whether the last interlock has been tested. If the last interlock has not been tested, the control unit 14 tests the next interlock starting at block 28A. If the last interlock has been tested, the"interlock test on "indicators and devices are deactivated at block 28S. The control unit 14 then returns the process to the main routine 22 at block 22R.

Described hereinafter are various testing mechanisms and interlock constructions that are suitably modified to become a functional part of applicant's novel interlock testing system schematically illustrated in FIG. 1. The added features of the interlock arrangements enable them to be used during an automatic testing phase in conjunction with the aforementioned control unit. Additionally, there are a number of embodiments that lend themselves to manual and/or automatic testing. The modified interlocks illustrated and described are merely intended to be examples of what has to be done to existing interlocks and new interlock designs to enable them to be part of a system for testing interlocks. Applicant's inventive testing system can be used with essentially all interlock arrangements that employ a change of state to register the functional aspects of the interlock, which change of state is sensed to test an interlock.

Referring now to FIG. 7, there is illustrated an interlock mechanism 30 which lends itself very well to being used in an automatic testing system of the type shown in FIG. 1.

This mechanism 30 consists of a push-button type limit switch 32 secured to a rubber mount 34 that is affixed to a machine bed 36 which is part of a machine M. The limit switch 32 includes a push-button 38, the outward movement of which acts to turn off the machine when the hinged guard 40 is moved away from the interlock 30, which guard is protecting a hazardous space of the machine M. Essentially, the limit switch 32 is part of circuitry wherein the switch 32 is normally biased into an open position to open a circuit to shut off the machine, but is held closed by the guard 40 when in its closed position. Thus, when the guard 40 is opened or the switch is spaced from the guard by the motorized screw 42 of the pusher unit 44 and the push-button 38 functions properly by moving outwardly, the interlocks will open the circuit to shut down the machine M. This constitutes the first phase of the test cycle.

The second phase of the test cycle completes the test and consists of the motorized screw 42 of the pusher unit 44 retracting and allowing the guard 40 to close and restore the push-button 38 of the interlock limit switch 32 to its original guarding state and the control unit checking if the interlock circuit functions as required in the restored state. The type of switch in this embodiment is referred to as being in the"normally open"position (off) and held closed (on) when the guard is in place. It is noted that in this embodiment, if the switch malfunctions to remain closed, the machine M will continue to operate. In this embodiment, as well as the others, where a guard is opened during testing, provision is made to insure that the guard will close after the testing is completed.

To avoid repetition, the second phase of the test cycle will generally not be described in the remaining embodiments of the interlock test arrangements. However, it is to be understood that the two-phase test cycle approach with the second phase consisting of restoring the interlock to its original guarding state and checking for proper function, is to be used with any interlock test system unless otherwise desired.

As aforementioned, if the testing process is to occur without shutting the machine down, the control unit monitoring the circuits containing the interlocks will be set to bypass the machine shutdown of each interlock when it is being tested and then effect actuation of the interlock as if the space guarded thereby has been breached. To avoid repetition, it is to be assumed that the testing system is set up to bypass the interlocks during the testing phase when desired with any particular interlock arrangement.

The embodiment of FIG. 7 can also be tested if the guard 40 is stuck or locked in position as shown in FIG. 8. As before, the push-button limit switch 32 and motorized screw 42 are secured to machine bed 36 through an intermediate rubber mount 34. When the screw 42 engages the stuck guard 40, the reaction force imposed by the screw 42 moves the tester pusher unit 44 containing screw 42 away from the guard, carrying along with it the limit switch 32, which movement is facilitated by the rubber mount 34 as shown in FIG. 8. In this position, the push-button 38 is free of guard 40 and is free to move to test the operation of the interlock 30.

Another modified interlock that will function as a part of applicant's novel testing system is shown in FIG. 9, which functions in a manner comparable to the embodiment of FIGS. 7 and 8 in conjunction with a program unit as described in FIG. 1. In place of the limit switch of FIG. 7, there is employed a magnetic interlock 50 which has a number of components similar to that disclosed in FIGS. 7 and 8. In this design, a resilient mount 52 is affixed to the guard 40 and connected to the resilient mount 52 is a portion 54 of the magnetic interlock 50. During the testing phase, if the guard 40 can open as, for instance, if it is hinged, the plunger of the tester pusher units 56 moves the guard 40 away to separate magnetic interlock portions 54,58 which varies the magnetic field to turn off the machine and thus test the operation of the interlock. In the event the guard 40 does not move, the resilient mount 52 will be compressed to separate the magnetic interlock portions 54,58 and thus permit testing of the magnetic interlock.

Another modified interlock construction used in applicant's testing system that functions in a manner similar to the embodiments illustrated in FIGS. 7 and 9 is shown in FIG.

10. This interlock uses as the tester mechanism a toggle mechanism 60 that is operated by a solenoid 62 when the interlock is to be tested and a spring 70. Connected to the end of the toggle mechanism 60 is a plunger 64 that acts like the motorized screw of FIG. 7 and the pusher units 56 of FIG. 9. If the guard 40 moves in the opening direction, the push-button 66 of the interlock limit switch 68 will be free to open the machine operating circuit or not, depending on its integrity. In the event the guard 40 is stuck, the interlock switch 68 will move back against the action of the spring 70, which movement is facilitated by the rollers 72 moving on the machine bed 36.

In FIG. 11, there is shown a design of interlock which is part of a test system that operates in a manner similar to those in FIGS. 7-10. In this arrangement, the interlock unit 80 includes a roller assembly 82 that is connected to a switch located in the interlock unit and is comparable to the push-button 38 in FIG. 7. The interlock unit 80 is connected to a solenoid actuated plunger 84 assembly that is part of the test mechanism that engages the guard 40. The plunger 84 is in engagement with guard 40 and is located in the pusher unit 85 mounted on a pair of flat springs 86 both of which are part of the test mechanism. Therefore, if the guard is stuck, the pusher and interlock units are free to move away from the guard to permit testing of the interlock.

In place of the resilient mounts employed in the embodiments of FIGS. 7 and 9, the rollers of FIG. 10 or the springs of FIG. 11, the interlock embodiment of FIG. 11 that can be part of the test system, uses an actuator such as the linear actuator 90. The linear actuator is by way of example only, since rotary actuators can be used or any other appropriate actuator design. In this embodiment, the actuator 90 includes a shaft 92 that is connected by a test arm 94 to an interlock sensor 96 having a push-button 98 extending therefrom. When the actuator shaft 92 is moved as shown in FIG. 13 by the programming of the control unit, the interlock sensor 96 is moved away from the guard and the push-button 98 is free to move to test the integrity of the interlock without opening the guard 40.

In the previous embodiments, the interlock mechanisms have employed switches that are disposed in the normally open position (machine off) and held in their closed position (machine on) by their respective guard. There are other arrangements in which the interlock switching arrangements are disposed in a normally closed position (machine on) and held open (machine off) by the guard when in an open position. This type of interlock design has the advantage that if the switch does not move to its closed position after the guard is closed, the machine will remain off, indicating its malfunction.

In FIG. 14, there is shown an interlock arrangement used in conjunction with a sliding guard barrier 100. In this design, the switch in sensor 102 is in the closed position (machine on) when the guard is fully closed. When the guard is opened, as shown in FIG.

14A, the switch in sensor 102 is moved to the circuit open position to turn the machine off.

To use this interlock as part of a testing system, the actuator shaft 103 of actuator 104 is connected through a test arm 106 that contacts a collar 112 affixed to a sensor arm 108. As illustrated in FIG. 14, when the guard 100 is closed, the sensor arm is biased into guard recess 110.

When the interlock sensor is to be tested, the actuator shaft 103 is moved by the linear actuator 104 to the position shown in FIG. 15 moving thereby the arm 106 against the collar 112 on arm 108. When this movement is accomplished and the interlock sensor opens the circuit, the interlock is acting properly and if not, the interlock has failed. FIG. 14A shows the guard in a partially open position wherein the sensor arm 108 has been moved by the guard barrier 100 to move the interlock to an open position comparable to the position it is moved to during testing.

In FIG. 16, there is illustrated a relay type interlock where the interlock sensor arm and the interlock test actuator are the same mechanism member 116. The relay type interlock 114 consists of a housing 115 in which is located the actuator 116. The actuator 115 is biased by compression spring 117 acting against ring 118 secured to the actuator 116 to which is also secured contact ring 119 which butts against contact pad 120 to place the switch in the normally closed position (machine on) in much the same manner as sensor arm 108 in FIG. 14. The housing 115 also contains a second sensor contact pad 113 secured to the housing 115, and utilized during testing of the interlock. In FIG. 16, the interlock is shown in its normally closed position (machine on). In normal interlock operation, the guard, when opened, will slide across the end of the sensor/actuator 116 in the manner illustrated in FIG.

14A, pushing the contact ring 119 away from the contact pad 120, putting the interlock in the open position (machine off). For testing, the control unit will institute the testing procedure, actuating the solenoid 121 pulling the contact ring 119 away from the contact pad 120 and closing the contact ring 119 onto contact sensor pad 113. This places the interlock in the open position, while at the same time indicating that the test mechanism has performed its opening test function. As can be appreciated, if the actuator 116 stays depressed and does not return to its extended state after testing, the interlock remains in the machine off position signaling an interlock or tester failure.

In certain situations, it may be desirable to provide for on-the-spot manual testing to determine if the interlocks are functioning properly before the guards are opened.

Such manual testing arrangements may or may not be in addition to remote testing capability with the use of a control unit. It is to be noted that while some provision could be made for bypassing the interlock during manual testing, the usual result would be to turn off the machine when the guard is moved or breached.

FIG. 17 discloses an interlock 122 that can comprise a normally open held closed switch as shown in FIGS. 7 and 9 or a normally closed held closed switch such as shown in FIGS. 14,15 and 16. The interlock 122 includes a push-button actuator 123 to which is connected disc 124. The actuator 123 is held in the position shown by a plunger 125 passing through a hole (not shown) in the guard 40 to which is connected a disc 126 that is biased against the disc 124 by spring 127 located between disc 126 secured to plunger 125 and guard 40. With the interlock being of the normally open held closed type the interlock 122 is manually tested by pulling the plunger handle portion 128 and connected disc 126 to the left away from the interlock 122 against the action of the spring 127. In this case, it is not necessary to open the guard 40 since pulling the plunger 125 and disk 126 away from the interlock allows the actuator 123 to change its state to shut off the machine and thus be tested to see if it is operating properly. Spring 127 restores the actuator to its original closed position after the handle 128 is released. As previously mentioned, the interlock 122 could be constructed so that in addition to on-the-spot manual testing, it can be remotely tested in the manner discussed with respect to the FIG. 7,9, etc., embodiments. This manual system can also be used with a normally closed held closed switch providing a spring 129 similar to spring 127 between disc 124 and bracket 130 secured to guard 40. Bracket 130 includes a hole (not shown) through which actuator 123 freely extends. Thus, to test a switch in the normally closed held closed position, the handle 128 is pushed in the direction of the guard 40, which pushes the actuator 123 inwardly to its open position by engagement with disc 124. Spring 129 restores the actuator to its original closed position after the handle 128 is released.

Referring now to FIG. 18, there is shown an interlock mechanism schematically illustrated by the box 132. Examples of interlocks that box 132 could represent include those shown in FIGS. 7,9,10,11, etc. When using one of those embodiments, the interlocks can be remotely tested by employing the systems previously discussed with respect thereto. In the FIG. 18 embodiment, the interlock 132 can be remotely or manually tested on site by the employment of a latch arrangement or suitable stops (not shown) permitting a limited predetermined pivotal movement of guard 133 away from the interlock 132. The guard movement would be only that predetermined limited amount necessary to test the interlock as it normally would be activated by opening the guard, but not sufficient to expose the operator to potential injury.

FIG. 18 illustrates a latch plate 140 having an opening slot 142 that receives a bolt 144 controlled by a solenoid operated mechanism 146. With the bolt 144 located in the slot 142, the limited travel of the guard is defined by the length of slot 142. The solenoid 146 is activated at the time the interlock is to be tested which only permits limited movement of the guard during testing by introducing bolt 144 into slot 142 in latch plate 140. If remote testing is being used, the control unit in the test system will be set so that if the interlock fails during the test, the bolt 144 will remain in place, thus preventing the guard from being opened to permit full access. A suitable key will be necessary to disengage the bolt, which key will be only available to an authorized person to permit the bolt to be removed from slot 142 and the guard 133 to be fully opened.

Another interlock embodiment that can be manually tested or remotely tested in conjunction with a control unit is disclosed in FIG. 19. This embodiment employs a light curtain 160 generated by an emitter 162 that forms the light curtain by directing a beam to a receiving sensor 164 via reflecting mirrors 166. When the curtain 160 is breached, the light path changes shading some of the mirrors 166 changing thereby the state of the light receiving sensor 164. Automatic testing can be accomplished by actuating the schematically illustrated solenoid 168 activated probe 169 inserted into the light path of the curtain 160 that would be tied into the system of the type disclosed in FIG. 1. Manual testing can be done with manually inserting a similar probe 169 into the light path or by merely breaching the curtain with one's hand.

Turning now to FIGS. 21-23, there is shown a mechanism similar to that disclosed in FIGS. 12 and 13 employing a linear actuator system for testing an interlock. The mechanism shown in FIGS. 21-23 illustrates the use of a linear actuator system to test an interlock that during the testing mode also actuates an integral locking mechanism 182 into engagement with a barrier guard latching member 180 to prevent the barrier guard 181 from being opened during the period that the interlock is being tested, and can be used to keep the barrier guard closed if the interlock has failed the test.

Essentially, this system consists of a mechanical arrangement whereby upon actuation of the linear actuator to test the interlock, a crank 204 is employed to move the locking member 182 into locking contact with the barrier guard latching member 180. This locking arrangement prevents access to the guarded space during the brief period the interlock is being tested. The assemblage also acts to keep the guard or barrier locked if the interlock fails the test and only permits it to be opened by an authorized person having the code or key to unlatch the guard for instance, for scheduled maintenance or repair. The lock engagement device is mechanically designed to be automatically actuated by the test mechanism to move a blade into locking engagement with the guard latching member 180 when the interlock is tested and to disengage the locking blade from the guard latching member 180 when the test is completed. This system and similar ones can be employed in conjunction with the subroutine of FIG. 5 which schematically illustrates the operating logic for the remote testing of interlocks in which the barrier guard locking mechanism is activated by and is integral with the test device.

FIG. 21 is a side view of the actuator mechanism shown in position in its normal position where it is located adjacent to a guard or barrier as illustrated in FIGS. 22 and 23. In FIG. 22, the locking member (lock engagement) blade 182 is shown out of engagement with the barrier or guard latching member 180. The locking member 182 is shown disposed in locking engagement with the barrier guard latching member 180 in FIG. 23.

Specifically, in FIG. 21, there is illustrated a base 184 on which is mounted the linear actuator 186. Extending from the linear actuator is the actuator shaft 188, at the front end of which is attached the cam block 190. The cam block 190 has attached to its upper end, the interlock test arm 192, to which is connected the interlock sensor 194 whose on/off sensor state is activated by the push lever arm 196. On the back end of the actuator shaft 188 is located a guide block 198 which limits the displacement and prevents rotation of the actuator shaft 188.

The guard lock engagement device includes a slide 200 which is integrally formed with the vertically disposed locking member 182 at its front end. The motion of the slide 200 which can glide freely on base 184 is controlled and restrained by the guide pins 202 mounted on the base 184. The back end of the slide 200 has a slot (not shown) which connects to arm 205 of the crank 204 via a slide pin 207 which is part of the crank 204. The crank 204 pivots about the crank pin 208 mounted on the base 184. The other arm 206 of the crank 204 has extending upward therefrom the cam pin 210 which is engaged with and moves along the cam slot 212 in block 190 in response to the movement of the cam block 190.

To test the interlock 194, the linear actuator 186 moves the shaft 188 in or out as required for each test phase imparting that motion to the cam block 190. The cam block 190 through the mechanism just described will move the slide 200 and its integral locking member 182 into locking engagement with the barrier guard latching member 180 when shaft 198 is retracted (FIG. 23) and out of locking engagement with the barrier guard when shaft 198 is moved outwardly (FIGS. 21 and 22).

Looking more specifically at the operation sequence in the position shown in FIG. 22, the lock engagement device is out of contact with the barrier guard latching member 180 and the crank arm 204 is positioned with the locking member in the retracted position.

Upon rotation of the crank 204 through the action of the pin 207 in the slot (not shown), the slide 200 and its integral locking member 182 is moved to its extended position shown in FIG.

23 to engage the guard 180, thereby preventing the guard barrier from being opened during the test.

It is to be understood that by judiciously redesigning the components of the lock engagement mechanism just described the motion of the slide 200 and its locking member 182 can be made linear or rotary, or a combination of these two types of motions in a desired plane and direction. This flexibility allows for the design of different practical engagement modes between the mechanism's locking member 182 and the guard's latching member 180.

Employing the logic of FIG. 5, if the interlock passes the test, the test system restores the interlock and the locking member to the position shown in FIGS. 21 and 22, thereby disengaging the locking member 182 from the guard or barrier latch. If the interlock fails the first test phase (retraction of the interlock), the actuator can be programmed to remain in its retracted state and lock the guard or barrier. If the second test phase fails (return of the interlock to its guarding position), the actuator can be programmed to retract the interlock again, thereby returning the locking member to the guard locking position keeping the guard or barrier locked. Thus, if the interlock fails either phase of the test, the guard or barrier can be kept locked to bar the access to the guarded space unless authorized.

Having described in detail systems for testing a guard closure, systems for testing interlocks and novel interlock testing constructions we turn to systems for testing closures with interlocks. In figure 24 there is a schematic illustration of the testing of interlocks of guards equipped with integral interlock-locking devices.

The integral interlock-lock is typically a device which houses both the interlock and the guard lock in a combined housing. The mechanical testing of the interlock for such a coupled device requires the unlatching of its lock from the guard before the interlock testing can be executed. This test subroutine 240 has the option of shutting down the machine due to test failures or put the interlock and/or lock in a bypass mode thus allowing the machine to continue to operate and subsequently test other interlock-locking devices if desired. It will also indicate and/or schedule the necessary repair or replacement of the failed devices.

In the figure 24 flow chart when this subroutine 240 is initiated the memory location storing the test states of the interlock and lock to be tested is reset at block 240A. It will be recognized that the memory location for a single interlock-lock device may be reset or the memory location for all interlock-lock devices may be reset. Next the system is set to bypass the lock function at 240B, bypass the interlock function at 240C and activate the"test on"indicators and devices at 240D. The next step is to unlatch the lock at 240E and if the lock did unlatch (change state) at 240F the interlock tester at 240G will change the interlock to the"guard open position"and test it. If the lock did not unlatch this will be recorded at 240H and indicate that the interlock can not be tested and the lock and interlock functions will be reinstated at 240I. Indicators will be activated at 240J to inform that the lock did not unlatch and that the interlock can not be tested. Scheduling of necessary lock repair and/or replacement will be signaled at 240K.

Returning now to 240G where the interlock was changed to the"guard open" position and tested we will move to 240L which will indicate whether or not the interlock changed to the guard open state. If it did not at 240M it will be recorded that the interlock failed the test. If the interlock passed the test 240N will record this occurrence. The interlock tester restores the interlock to the"guard closed"position where it is tested at 240U. At 240V it is determined if the interlock returned to the"guard closed state". If not it will record that the interlock failed the test at 240W and if it passed the test a record is made at 240X. In both instances the system proceeds to 240P where the lock will be commanded to be relatched and tested. At 240Q there will be a test to determine if the lock did change its state and thus relatched. At 240R it will record if the lock failed the test and if the lock relatched it will be recorded at 240S and the lock function will be reinstated at 240T by removing the bypass. If the interlock and lock passed all the tests as indicated at 240Y the interlock function will be reinstated by removing its bypass at 240Z and the"test passed"indicator and devices will be activated at 240AA. If the interlock and lock did not pass all the tests, the test failed warning indicator devices will be activated at 240BB and then one may choose to shut down the machine due to test as failures indicated at 240CC by shutting down the machine at 240DD.

The machine shut down is followed by the reinstating of the bypassed functions at 240HH and by the deactivation of the"tests on"indicators and devices at 24011. If the choice at 240CC is that one does not want the machine to shut down then at 240EE the interlock and/or lock will be left in the bypass mode allowing the machine to continue to operate and schedule necessary repair or replacement of the failed devices. If it is the last interlock tested as indicated at 240FF the test and indicators will be deactivated at 240GG which returns the system to the main routine. If additional interlocks/locking devices are to be tested the routine returns to 240A and starts the testing again for another interlock-lock device.

In figure 25 there is illustrated a guard closure test subroutine for closures that are protected by interlocks. The subroutine is designated by the number 250. In starting the system, the memory for the guard closures to be tested is reset to the proper test states at 250A. Following this the interlock function is bypassed at 250B and the guard closure test indicators and devices are activated at 250C. The guard closure is then tested at 250D by applying a tester probe to the guard closure. At 250E it is determined whether or not the probe deployed. If the probe did not deploy the interlock function will be reinstated by removing the bypass and at 250F and it is recorded at 250G that the probe did not deploy and the guard cannot be tested. At 250H activated indicators will be showing that the probe did not deploy and that the guard cannot be tested, following which at 250J the necessary tester repair and/or replacement will be scheduled.

Returning to the indicator 250E, if the tester indicates that the probe did deploy the next test is at 250K where it is determined if the guard closure did open or is opened by the probe. If the closure did open or is opened 250L will record that the guard closure failed the probe test. If the guard closure is not open and did not open 250M will record that the guard closure passed the test. The next step is to use the interlock to make a redundant closure test check. At 250P there will be an indication as to whether or not the interlock is known not to be faulty and if the interlock is not known not to be faulty 250Q will indicate that the interlock is not to be used to make a redundant closure test check. If the interlock is known not to be faulty the interlock is used to make a redundant closure test check at 250R.

The interlock state is then determined at 250S. If the closure test changed the interlock to the "guard open"state, 250T will indicate that the guard closure failed the redundant interlock check test. If at 250S the interlock did not change to the"guard open"state 250U will indicate that the guard passed the redundant interlock closure test. The paths from 250U, 250Q, 250T and 250L all lead to 250V where the closure tester probe is commanded to retract from the closure and its retraction status is tested at 250W. If 250W indicated that the probe did retract then at 250X it will be determined that the closure and probe passed all tests.

If the probe did not retract it will be recorded that the probe did not retract at 250Y and the indicators at 250Z will show that the probe did not retract and the necessary tester repair and/or replacement will be scheduled at 250AA If the closure and probe did pass all the tests at 250X the"test passed" indicators and devices are activated at 250BB and the interlock function is reinstated at 250CC by removing the bypass. If the closure and probe did not pass all of the tests the test failed warning indicators and devices will be activated at 250DD and a selection at 250EE will be made to shut down the machine due to test failures by shutting down the machine at 250FF or choose not to shut down the machine and put the interlock in the bypass mode at 250GG to allow the machine to continue to operate and schedule necessary replacements of the failed devices. If it is the last closure to be tested as indicated at 250HH the guard closure test indicators and devices will be deactivated at 25011 and the system returns to the main routine.

If at 250HH it is determined that it is not the last guard closure to be tested, then the testing process will start all over with the next scheduled guard closure by returning to 250A. If the machine is shut down at 250FF, then it is followed by the reinstating of the bypassed interlock function at 250LL and by the deactivation of the"guard closure test on"indicators and devices at 250MM In Figures 26a and 26b there is illustrated a guard closure test subroutine 260 for closures protected by interlocks wherein there is sequential testing of first the interlock and then the closure. When starting the system the memory for the interlock/guard closure to be tested is reset to the proper states at 260A. Following this the interlock function is bypassed at 260B and the"interlock/guard closure tests on"indicators and devices are activated at 260C. The next step is to test the interlock which is shown in figure 26b wherein at 260D the interlock tester is used to change the interlock to the"guard open"position. At 260E it will be determined if the interlock did change to the"guard open"state and if it did not it will be recorded that the interlock failed the test at 260F or that it passed at 260G. Then at 260H the interlock tester acts to restore the interlock to the"guard closed"position and tests it. At 260I it will indicate whether or not the interlock returned to the"guard closed"state. If it did not, a record that it failed the interlock test will be made at 260J or that the interlock passed the test at 260K. Following this, the guard closure is to be tested and reference is now made again to figure 26a wherein at 260L the guard closure is tested by applying a tester probe to the guard closure. At 260M it is determined whether or not the probe deployed. If the probe did not deploy the interlock function will be reinstated by removing the bypass at 260N and at 260P it is recorded that the probe did not deploy and the guard cannot be tested. At 260Q activated indicators will reflect that the probe did not deploy and that the guard cannot be tested. Following at 260R the necessary tester repair and/or replacement will be scheduled and the program controller will index to test the next interlock/closure at 260S.

Returning now to 260M where if it has been indicated that the probe did deploy, the next test is at 260U where it is determined if the guard closure did open or is opened by the probe. If the closure did open or is opened which should not have been the case 260V will record that the guard closure failed the probe test. If the guard closure is not and did not open 260W will record that the guard closure passed the test. The next step is to use the interlock to make a redundant closure test check. At 260X there will be an indication as to whether or not the interlock passed the test and if it did not 260Y will record that the interlock is not to be used to make a redundant closure test check. If the interlock did pass the test the interlock is used to make the redundant closure test check at 260Z and at 260AA it will be tested to see if the interlock changed to a"guard open"state. If the closure test changed the interlock to the"guard open state"260BB will indicate that the guard closure failed the interlock test. If at 260AA the interlock did not change to the"guard open"state, 260CC will indicate that the guard closure passed the interlock test. The paths from 260CC, 260Y, 260BB, and 260V all lead to 260DD where the closure tester probe is commanded to retract from the closure as indicated at 260DD and its retraction status is determined at 260EE. If 260EE indicates that the probe retracted, then at 260FF it will be determined if the closure, interlock and probe did or did not pass all tests. If the probe did not retract it is recorded that the probe did not retract at 260GG and indicators at 260HH will show that the probe did not retract and the necessary test repair and/or replacement will be scheduled at 26011. The process then proceeds to 260FF.

If the closure and probe did pass all the tests at 260FF, test passed indicators and devices are activated at 260JJ and the interlock function is reinstated at 260KK by removing the bypass. If the closure and probe did not pass all of the tests the"test failed" warning indicators and devices will be activated at 260LL. Subsequently, a selection can be made at 260MM to shut down the machine due to test failures by shutting down the machine at 260NN. After shutting down the machine the interlock function will be reinstated at 260PP and testing is deactivated at 260QQ and the process returns to the main routine shown in figure 29. If the choice is made not to shut down the machine the interlock is put in the bypass mode at 260RR to allow the machine to continue operating and schedule necessary replacements of the failed device. If it is the last closure to be tested as indicated at 260S the interlock/guard closure test indicators will be deactivated at 260SS and the process returns to the main routine shown in figure 29. If not the process will be repeated for testing another closure protected by an interlock.

We turn now to an additional novel embodiment of applicant's invention as shown in figures 27a and 27b. Here the guard closure is protected by an integral interlock- lock, the testing of which was described in figure 24. This embodiment calls for the sequential testing of the interlock and then the closure. When this subroutine 270 is initiated the memory location storing the test states of the interlock-guard closure to be tested is reset at 270A. It will be recognized that the memory location for a single location for a single interlock-lock may be reset or the memory location for all interlock-lock devices may be reset.

Initially, the system is set to bypass the lock function at 270B, bypass the interlock function at 270C and activate the"test on"indicators and devices at 270D.

Reference is now made to figure 27b wherein a system is shown for testing the interlock which by way of reference is similar to figure 24. In this arrangement the first step is to unlatch the lock at 270E. If he lock did unlatch (change state) at 270F the interlock tester at 270G will be commanded to change the interlock to the"guard open position"and test it.

If the lock did not unlatch this will be recorded at 270H and it will be indicated that the interlock cannot be tested. The lock and interlock functions will be reinstated at 270I and indicators will be activated at 270J to inform that the lock did not unlatch and thus the interlock cannot be tested. Scheduling of necessary lock repair and/or replacement will be signaled at 270K. Following this the guard closure is to be tested and reference is made to B on figure 27a.

However, as aforementioned this system provides for testing the interlock which is done if the lock did unlatch. To this end we return to 270G wherein the interlock tester is used to change the interlock to the"guard open"position and test for its change of state.

At 270L there would be an indication of whether or not the interlock changed to the guard open state and if it did not at 270M it will record that the interlock failed the test.

If the interlock passed the test 270N will record this occurrence. The interlock tester restores the interlock to the"guard closed"position where it is tested at 270U. At 270V it is determined if the interlock returned to the"guard closed state". If it did not it will be recorded that the interlock failed the test at 270W and if it passed the test a record is made at 270X.

In either instance the system proceeds to 270P where the lock will be commanded to be relatched and tested. At 270Q there will be a test to determine if the lock did change its state and thus relatch. At 270R it will record if the lock failed the test. If the lock relatched it will be recorded at 270S that it passed the test and the lock function will be reinstated by removing the bypass at 270T.

Following the recording of all passed or failed tests the system returns to test the guard closure at item B in figure 27a.

The system for testing the guard closure in figure 27a is similar to that which has been set forth in figure 26a. Specifically, at 270AA the guard closure is tested by applying a tester probe to the guard closure. At 270BB whether or not the probe deployed is determined. If the probe did not deploy then at 270CC it is recorded that the probe did not deploy and the guard cannot be tested. At 270DD activated indicators will reflect that the probe did not deploy and that the guard cannot be tested. Following at 270EE the necessary test or repair and/or replacement will be scheduled and if at 270FF it is determined that the interlock testing was not performed the program will index at 271 C to test the next interlock/closure. If the interlock-lock testing was performed as indicated at 270FF and it passed as determined at 270CD, then at 270GG (item C) is where the interlock function is reinstated and the"tests passed"indicators are activated. If the interlock-lock did not pass its test then this will be suitably indicated at 270CD and the program will proceed to 270XX, (item D).

Returning now to 270BB where if it has been indicated that the probe did deploy the next test is at 270HH where it is determined if the guard closure did open or is opened by the probe. If the closure is open or is opened, which should not have been the case, 27011 will record that the guard closure failed the probe test. If the guard closure is not opened 270JJ will record that the guard passed the test. The next step is to use the interlock to make a redundant closure test check. At 270KK there will be an indication as to whether or not the interlock passed the test and if it did not 270LL will record that the interlock is not to be used to make a redundant closure check. If the interlock did pass the test the interlock is used to make the redundant closure check at 270MM and at 270NN it will be tested to see if the interlock changed to a"guard open state". If the closure test changed the interlock to the "guard open"state 270QQ will indicate that the guard closure failed the interlock test. If at 270NN the interlock did not change to the"guard open"state 270PP will indicate that the guard closure passed the interlock test. The paths from 270PP, 270LL, 270QQ and 27011 all lead to 270RR where the closure tester probe is commanded to retract from the closure as indicated at 270RR. If the probe retracted or not it would show at 270SS. If the probe did retract, then at 270TT it will be determined if the closure, the interlock-lock and probe passed all tests. If the probe did not retract it is recorded that the probe did not retract at 270UU and indicators at 270VV will show that the probe did not retract and the necessary repair and/or replacement will be scheduled at 270WW. The process then proceeds to 270TT.

If the closure, interlock-lock and probe all passed their tests"test passed" indicators and devices are activated and the interlock function is reinstated at 270GG by removing the bypass. If the closure, interlock-lock and probe did not all pass their tests,"test failed"warning indicators and devices will be activated at 270XX. Subsequently a selection is made at 270YY to either shut down the machine due to test failures at 270ZZ after which the interlock function is reinstated and testing indicators are deactivated at 271 A or the process returns to the main routine shown in figure 29 to, or the selection is made to not shut down the machine and put the interlock and/or lock in the bypass mode at 271B to allow the machine to continue operating and schedule necessary repair or replacement of the failed device. If it is to be the last closure tested as indicated at 271 C the"tests on"indicators will be deactivated at 271D and the process returns to the main routine shown in figure 29. If not the process will be repeated starting at the beginning for testing and another closure integral interlock-lock device.

Figure 28 illustrates a guard closure test subroutine for testing a closure protected by interlocks. In this system there is simultaneous testing of both the closure and the interlock by using the same tester. The interlock and/or the tester are compliant base mounted for this purpose which makes this approach possible. The operation and structure of various types of interlocks mounted on a compliant base, interlock testers, test systems and test methods for such has previously been discussed in detail. In essence the interlock will be bypassed and the guard closure and the interlock will be tested by deploying the tester probe to the guard closure and if the closure is locked and cannot be opened the interlock will retract and thus can change state, thereby permitting the testing of the interlock, and if the closure opens in response to the tester the interlock member will be tested due to its freedom to move upon opening of the closure which move again permits the interlock to change state.

Figure 28 is a flow chart illustrating the components of this system 280. At 280A the program test states of the interlock/guard closure to be tested are reset. At 280B the interlock function is bypassed and at the same time at 280C the"interlock/guard test on" indicators and devices are activated. Following this the guard closure and interlock are tested at 280D wherein the tester probe is moved to engage the guard closure and test the closure and interlock. At 280E it will be determined if the probe deployed and if it did not the interlock function will be reinstated at 280F and the fact that the probe did not deploy and that the guard and interlock cannot be tested is recorded at 280G. Indicators at 280H inform that the probe did not deploy and that the guard and interlock cannot be tested following which the necessary tester repair and/or replacement will be scheduled at 280I. Next, the process moves to 280J and acts to test another interlock/guard closure or if this is the last closure to be tested the"test on"indicators will be deactivated at 280K and the process returns to the main routine shown in figure 29. If the probe did deploy at 280E then at 280M there is a determination if the guard closure opened upon being acted upon by the probe or is open. If the guard closure is opened or is open there will be a record made that it failed the probe test at 280N and if the guard closure did not open it will be recorded that the guard closure passed the test at 280P.

If the probe has moved the guard to the open position the interlock is free to move and thereby change to the"guard open"state, and at 280Q it is determined if it did so.

If the interlock changed state it will be indicated that the interlock passed this test at 280S or if it did not change state the test failure is indicated at 280R. At 280T the tester probe is commanded to retract from the closure and at 280U there will be a determination as to whether or not the probe did retract. If the probe retracted the process moves to 280V. If the probe did not retract a record of this is made at 280W and indicators will activate at 280X indicating that the probe did not retract, upon which the necessary repair and/or replacement will be scheduled at 280Y and the process proceeds to 280V.

Returning now to 280V if the interlock did not return to the"guard closed" state a record that the interlock failed the test will be made at 280AA and if it passed the test at 280BB. Then at 280CC there will be a determination whether the closure, interlock and probe passed all their tests and if they did then at 280DD the interlock function is reinstated by removing the bypass and 280EE will indicate that all tests have been passed. If the closure, interlock and probe did not pass their tests then the test failed warning indicator will be activated at 280FF and then at 280GG a decision is made whether to shut down the machine or not due to test failures. If the machine is shut down that will be done at 280HH and following that the interlock/guard closure test indicators and devices will be deactivated at 28011 and the interlock function will be reinstated at 280JJ, and the process returns to the main routine of figure 29.

If the closure is not to be shut down then as shown at 280KK the interlock continues to be in the bypass mode which allows the machine to continue to operate and the necessary repair and/or replacement of the failed devices will also be scheduled at 280KK Following this, it is determined at 280J if a new interlock/closure will be tested or if it is the last closure to be tested, then the interlock/guard closure test indicators will be deactivated at 280K and the process returns to the main routine of figure 29.

Figure 29 illustrates a main routine 290 which controls the running of a machine and also directs the testing of its guard closures and interlocks by means of the set of subroutines of figures 2,24,25,26,27, and 28. The main routine 290 is similar to that previously described with respect to figure 3 for testing interlocks only.

The main routine 290 directs the testing of the closures and the testing of the interlocks to be performed during running of the machine and during the rundown phase of the machine when the machine is shut down. It does so without shutting the machine down due to the testing. For reasons of safety, it is important to establish that during running of the machine and during its rundown phase, access is denied to the guard protected spaces containing running machine components, and that the interlocks provide the designed for protection. The guard closure and interlocks testing methods, processes, devices and systems of this instant invention are designed to determine if that is the case, or if the case is that any specific guard closure and/or interlock have failed, hence no longer provide the expected protection. These are conditions which would be unknown without testing.

The control unit 290A of the machine system may process all input and outputs, monitor all switches, and determine whether the machine is operating properly. The main disconnect may be opened or closed at block 290B and it will be determined at 290C whether the main disconnect is opened or closed. If it is not closed the machine will be turned off at 290D. If the main disconnect is closed then the start/stop controls will be queried at 290F and it will be determined at 290F if the control is in the start position. If the control is not in the start position the machine will be turned off at 290G. The emergency or other stop controls will be activated or deactivated at 290H and at 290I it will be determined if the stop controls have been activated or not. If the stop controls have been activated the machine is turned off at 290J and after the machine motion has stopped the guards will be unlocked if required at 290K. If the stop controls are not activated it will be determined if the input/output (I/O) controls are enabled at 290L. If they are not enabled it will be so indicated at 290M. If the controls are enabled there will be a determination at 290N if the machine controls other than the interlocks are satisfied. If they are not the machine will be turned off at 290P and after the machine motion has stopped the guards will be unlocked if required at 290Q before returning to the main system control unit at 290A.

If the machine controls other than the interlocks are satisfied there will be a determination at 290R as to the satisfaction of the interlock sensor states. For any interlock whose sensor states are not satisfied it will be determined at 290S if its interlock/lock bypass has been enabled by the interlock test subroutine when the interlock was tested. If the interlock bypass has not been enabled, the machine will be turned off at 290P. If the bypass is enabled at 290S, or the interlock sensor states are satisfied at 290R, then at 290T it will be determined if the interlock and/or the guard testing is in progress. If the testing is in progress there is a return to the machine control system at 290A. If the testing is not in progress the determination will be made at 290U if the machine is running. If the machine is running a determination is made at 290V whether or not to shut down the machine. If the machine is not to be shut down it will be determined at 290W if the interlock and/or guard tests are to be initiated. If they are to be initiated and conducted, they are performed at 290Y by utilizing the appropriate test subroutine from the sets illustrated by figures 2,24,25,26,27, and 28 In parallel with the testing initiation, control is returned at 290X to the machine system's main control unit 290A, so that the machine can be checked and kept under control while the testing is in progress. If at 290V it is determined to shut down the machine, the machine run down phase will be initiated at 290Z and the interlocks and guards will be tested at 290W during this rundown phase by utilizing the appropriate test subroutine from the sets illustrated by figures 2,24,25,26,27, and 28. In parallel with the testing initiation, control is returned at 290X to the machine system's main control unit 290A, so that the machine can be checked and kept under control while the testing is in progress. After completing the tests at 290Y a determination is made at 290AA if the test subroutine at 290V shut the machine off. If the subroutine at 290Y did not shut off the machine, then 290AA returns to the machine's main control unit 290A. If the subroutine 290Y did shut off the machine, then 290AA branches to 290BB where after the machine motion has stopped the guards will be unlocked if required.

To complete the description of the system we return to 290U and discuss what occurs if it has been determined that the machine is not running. If it is determined at 290CC that the machine is not running the guards will be closed and locked to enable machine startup.

Following this at 290DD it will be decided whether to start the machine or not. If the decision at 290DD is not to start the machine then the control branches to 290P, the"machine off'status. If the decision is to start the machine, then the machine's running status is determined at 290EE. If running, the control branches to 290W. If not running then control branches again to 290P, the"machine off'status.

Figures 30-36 there are illustrated various embodiments of structures that can be used when testing the status of guard closures alone or combined with interlocks. These are but two examples of a wide variety of mechanisms that can be employed.

The testing of the guard closures is to be performed when their status is supposed to be"the guard closure is closed and cannot be opened". This is the case during running of a machine when the closure is meant to prevent the access to a space containing the hazards of running machine components or other hazards. It is also the case when the machine is shut down and the protected machine components are running down to zero speed.

Figures 30,31 and 32 illustrate the working of a force displacement type device using a probe for testing the position status of a guard closure. In this embodiment the closure tester is separate from an interlock arrangement but it can be appreciated that an interlock device separate from the tester as well as a device for testing the interlock may be present if desired. In figures 30,31 and 32 a lock is provided to keep the guard closure latched closed while the closure is in its hazard protective status. In the subject arrangement the test determines whether the guard closure opens or not due to the test or whether it is found in the open position. If the closure is operating correctly (locked) when the test is employed the guard closure should neither be open nor should it open in response to the tester probe.

Referring specifically to the three figures which illustrates different positions of the same embodiment there is shown by way of example only a hinged closure 300 that is being tested. The invention is applicable to testing slidably or otherwise movable closures as well as fixed closures while in their hazard protective status. Similarly, the instant embodiment can use a pusher probe of any suitable force including a pulsating force. Likewise, testers other than a pusher type can utilize the testing method described here.

The tester assembly 302 in figure 30 is shown connected to a rigid mount 304 that is connected to a machine bed 306. Also secured to the machine bed is a closure lock 308 that is designed to maintain the closure in the locked position. As aforementioned, the purpose of the subject test is to determine if the closure cannot be opened, or it can be opened due to whatever cause, one of which can be the failure of the lock. Furthermore, this tester assembly 302 is capable of being checked during testing to determine that the tester probe is functioning correctly. If a separate interlock which is an integral interlock-lock is to be tested the lock 308 can be designed to be unlatched and relatched as required by such a test.

Because of this action the unlatching and latching functions of the integral lock are also tested for. The testing device of Figures 30,31 and 32 can be utilized in conjunction with the flow diagrams discussing the operation of the various routines for testing guard closures, interlocks and locks etc., disclosed in detail with respect to figures 2,25,26 and 27 previously described.

To test whether the closure 300 is closed and cannot be opened, or can be opened or is open the tester assembly includes a probe 310 located in a housing 312. The probe 310 is moved by a tester/motor actuator 314 located at the rear of the housing 312.

The probe 310 has secured to its outer end thereof a gripper member 316 that includes a set of jaws that are in the normally open position. The gripper member 316 includes a touch trigger (not shown) which when it comes into contact with the closure handle 320 closes the gripper jaws around the closure handle 320. This type of gripper, because of its touch trigger, will latch on to the closure handle regardless if the closure cannot be opened, or if it can be opened, or if it is open. The movement of the probe assembly 310 is limited by the collar 318 which will engage the housing when in its extended position as shown in figure 32.

Attached to the collar 318 is a probe displacement contact member 322 that during probe movement glides along the probe position sensor 324 that is mounted in the probe housing 312. The position sensor can be a continuous strip or can consist of a row of discrete position sensors and functions to indicate the position of the probe which is suitably recorded. As shown in figure 30 the gripper 316 is spaced from the handle 320 by a gap.

When the test is initiated, the probe is commanded to move the probe gripper 316 toward the closure handle 320. If the gap between them is closed, then this gap closure will be indicated by the contact member 322 on the position sensor 324, and such movement will determine that the probe 310 has deployed. If no movement was indicated, then the probe 310 has failed to deploy for testing, which is a tester failure. When the probe 310 is moved by the tester motor 314 the position is monitored by the sliding movement of the contact member 322 relative to the position sensor 324.

Turning to figure 31 there is shown the position of the various components when the gripper member of the tester probe comes into gripping contact with the handle 320 of the hinged closure. In that position it is assumed that the closure remains in the closed position and cannot be opened by the tester probe. Suitable indicators will record this movement to show that the probe 310 moved only that amount to engage the closure handle 320 and thus that the guard closure passed the test in that it remained in the closed position.

In the event the closure can be opened or is open the closure is moved to the open position shown in figure 32 by the power driven probe 310. When this occurs the sensors 324 will indicate that the probe has extended a certain distance and thus the closure did fail its test.

When the test is completed the tester is retracted and tests are conducted to check if the tester returned to the position shown in Figure 30. The retraction action forces open the gripper jaws of the tester.

The above mentioned probe retraction may result in the probe retracting only partially or not at all. In that case, it will be so indicated by the position of the contact member 322 on the position sensor 324, which will thereby signal that the probe 310 has failed to retract as commanded, which is a tester failure.

Turning now to figures 33,34,35 and 36 there is illustrated an arrangement in which there is the testing of a closure guard by a force displacement member identical to that disclosed in figures 30-32. The identical components are given the same numbers and the description of their operation is set forth in the previous paragraphs. This arrangement distinguishes from the previous design in that the closure tester assembly is connected to an interlock assembly that is resiliently mounted to the machine base. Also, this arrangement performs both the closure test and interlock test simultaneously, with the same common tester as is illustrated in figures 33 through 36. The arrangement works equally well when the interlock is attached to the tester and the tester is resiliently mounted to the machine base.

Figure 28, previously described, discloses a flow chart as to how the various components are tested and what takes place in the event the closure and/or interlock passes or fails its tests.

Referring first to figure 33 it is noted that tester assembly 302 is secured to an interlock 332 which is in turn secured to a resilient base 334 that is connected to the machine base 306. Lock 308 is also connected to the machine base and functions to lock the hinged closure 300 in position against the machine base. As shown, the interlock 332 has a sensor member 336 in contact with the hinged guard 300. The testing of this type of interlock arrangement is described in detail to figures 7 and 8 herein. The interlock normally acts to turn off the machine when the guard is opened or its state is otherwise changed. Therefore, during the testing the interlock is bypassed so that testing can proceed while the machine is running, without the test shutting down the machine. The previously described flow chart in figure 28 sets forth in detail the testing procedure of the closure and interlock.

Also in figure 33 there is shown a tester displacement rigid blocker 342 which is connected to the machine base 306. This blocker has a sensor contact 344 attached to it and a matching sensor contact 346 is located on the near end of the test assembly 302.

The combined closure and interlock testing of the embodiment shown in figures 33, 34, 35 and 36 starts by the tester/motor actuator 314, being commanded to move the probe 310 toward the closure 300. As previously described with respect to figure 30, if by this probe movement the gap present between the gripper 316 and the closure handle 320 shown in figure33 is closed, then the contact member 322 will indicate this on the position sensor 324, and such movement will determine that the probe 310 has deployed. If no movement is indicated, then the probe did not deploy for testing, which is tester failure.

If the probe does deploy, then the gripper jaws 316 will engage the closure handle 320 and latch on to it, as shown in figure 34. At this stage the tester/motor actuator 314 continues pushing the probe 310 toward the closure 300. If the closure is closed and cannot be opened then the situation shown in figure 35 will take place.

As shown in figure 35 the tester 302 and interlock 332 will move in the direction away from the closure 300, ending up butting against the rigid blocker 342. This is made possible because the resilient base 334 will distort as shown in figure 35, to accommodate this movement. The contact sensors 344 and 346 will indicate that this butting of the tester 302 against the blocker 342 has taken place. This indication together with the position of the contact member 322 on the position sensor 324 will indicate that the closure 300 is not open and cannot be opened, and the closure has passed the test.

As is further shown in figure 35, the butting position of the tester 302 against the rigid blocker 342 removes the interlock from contact with the closure 300, and thus frees the interlock sensor member 336 to be able to change to its"guard open"position. This tests the interlock as described in detail with respect to figures 7 and 8 herein.

At the completion of the combined closure and interlock test of figure 35, the tester/motor actuator 314 is commanded to retract the probe 310 to the position shown in figure 33. The retraction action forces open the gripper jaws of the probe, freeing the closure from the probe.

As is shown in figure 33, the retracted position returns the interlock sensor member 336 to its"guard closed"position. Checking if this return results in the change of the interlock to its"guard closed"state constitutes the second part of the interlock testing routine as described in detail with respect to figures 7 and 8 herein.

The previously mentioned command to retract the probe 310 from the position shown in figure 35, to that shown in figure 33, may result in the probe retracting only partially or not at all. In that case, it will be so indicated by the position of the contact member 322 on the position sensor 324, which will thereby signal that the probe 310 has failed to retract as commanded, which is a tester failure.

If the tester shows that the closure 300 can be opened or is open, then this constitutes a closure failure. The situation shown in figure 36 typifies this, if the opening resistance of the closure 300 to the force applied to it by the probe 310 is sufficiently large.

As shown, the tester 302 and the interlock 332 will move in the direction away from the closure 300, ending up butting against the rigid blocker 342. This is made possible because the resilient base 334 will distort as shown in figure 36, to accommodate this movement. The contact sensors 344 and 346 will indicate that this butting of the tester 302 against the blockers 342 has taken place. This indication, together with the extended position of the contact member 322 on the position sensor 324 will indicate that the closure 300 can be opened or is open hence has failed the test.

The situation can ensue, such that the closure 300 opens so easily or so far that the resilient mount 334 does not distort or does not distort sufficiently to cause a butting contact between the tester 302 and the rigid blocking member 342. In this situation the probe ends up in its fully extended position. The position of the contact member 322 on the position sensor 324 will indicate that this is the case, and thereby indicate that the closure can be opened or is open, and thus the closure has failed the test.

In either closure open or opening case described above, the interlock sensor member 336 is removed from contact with the closure 300, and thus frees the interlock sensor member 336 to be able to change to its"guard open"position. This tests the interlock as described in detail with respect to figures 7 and 8 herein.

At the completion of the closure test for which the indication is that the closure 300 can be opened or is open, the tester/motor actuator 314 is commanded to retract the probe 310 to the position shown is figure 33. The retraction action forces open the gripper jaws of the probe, freeing the closure from the probe.

The retracted position returns the interlock sensor member 336 to its"guard closed"position. Checking if this return resulted in the change of the interlock to its"guard closed"state constitutes the second part of the interlock testing routine as described in to figures 7 and 8.

The previously mentioned command to retract the probe 310 to the position shown in figure 33, may result in the probe retracting only partially or not at all. In that case it will be so indicated by the position of the contact member 322 or the position sensor 324, which will thereby signal that the probe 310 has failed to retract as commanded, which is a tester failure.

It is intended to cover by the following claims all embodiments which fall within the true spirit and scope of the invention.