TECHNICAL FIELD

The present generally concerns emergency braking systems, and more particularly to a synchronized emergency braking system used in vertical transporting machines such as, but not limited, to elevators.

BACKGROUND

Lifting transport equipment, such as elevators, hoists and the like, are well-known and widely used in the construction industry. The lifting equipment is generally used to move loads between numerous levels from the ground up, and maybe located either on the interior or the exterior of a building under construction or being renovated. The lifting equipment includes a platform on which the load is placed. To prevent uncontrolled dropping of the lifting equipment, emergency mechanical safety devices, which is typically included with rack and pinion equipment, are used. Such devices are able to detect downward overspeed, i.e. free fall which is pre-set to a specific speed (known as the “tripping speed”)and which then triggers a complete braking of the equipment. Generally speaking, this design of safety device is known as a safety brake with centrifugal governor and may also be known as a ‘’parachute brake”.

The pre-set tripping speed is calibrated either prior to installation of the lifting equipment or is done on-site. The calibration is generally imprecise (± 5 ft/min) due to the safety device design. The safety device, typically called a (SAJ Type) within the lifting equipment industry is purchased from a third party and installed without modifying the brake design other than the activation speed calibration. Typically, the SAJ type safety device is used for construction hoist anti-fall and ensures the safe operation of the construction elevator safety components. In a situation where a construction elevator is falling, the anti-fall safety device activates which will spin a conical drum coupled to brake pads and the brake torque is gradually increased while contact between the drum and brake pads increase. After braking for a certain distance, which is also generally imprecise due to brake design and a few external factors (mass, gearbox, inertia, wear and the like), the cage will stop smoothly on the rail frame, thereby ensuring the safety of the hoist, its load, and its passengers. A number of groups have attempted to address these issues with designs such as those exemplified below:

US patent no. 4,254,941 to Tanson for Automatic Anti-Fall Device for Manual or Motorized Lifting Systems;

US patent no. 7,080,717 to Ito for Emergency Brake Apparatus of Elevator;

US patent no. 7,311,179 to Franklin for Elevator Dampening System;

US patent no. 8,602,170 to Fischer for Multiple Brake Device for Elevator with Monitoring;

US patent no. 9,169,104 to Legeret et al for Activating a Safety Gear;

US patent no. 9,206,015 to Osmanbasic for Safety Brake with Resetting;

US patent no. 9,273,739 to Meierhans for Brake System;

US patent no. 9,457,989 to Meierhans for Braking device with Actuating Device;

US patent no. 9,975,733 to Cunningham for Elevator Safety Device; and

US patent no. 10,358,320 to Bitzi for Elevator Brake.

Disadvantageously, the designs noted above are generally overly complex and as such would likely be prohibitively expensive to install and need extensive maintenance, or worst disassembly while in its life cycle. Moreover, the complexity would likely reduce the available assembly area on the hoist thereby rendering them impractical for use on construction sites.

Thus, there is, a need for a synchronized braking system that links together two brakes and which addressed the above noted problems.

BRIEF SUMMARY

We have significantly reduced, or essentially eliminated, the problems associated with the designs described above by designing a synchronized braking safety system that exceeds the current SAJ safety device capacity limitation of 17 636 lbs. Our synchronized braking system allows us to install two SAJ safety devices in a single apparatus in a servo mechanical fashion. In short, it interconnects both activation systems and permits synchronization of both devices’ activation.

Our synchronized braking system is a novel and unobvious dual centrifugal safety device system for use mainly with a rack and pinion arrangement. The design provides higher capacity equipment, which affects the maximum braking capacity which now reaches 31000 lbs. Additionally, since Machine Code Directives restrict the maximum permitted net floor area based on the Rated Load capacity of the lifting equipment, our designs which now allow higher capacities, then also allow larger net floor area, which would otherwise be limited by the machine rated load (load capacity). This means that a higher load capacity allows us to design machines larger than ever before. Advantageously, our braking system permits the braking load to be shared. This reduces strain on the rack and pinion teeth thereby reduces damage thereto. In summary, the system allows for a higher loading capacity compared to conventional systems and provides a larger floor dimensions area. Finally, the system allows for easier manual reset for the brakes; and provides a so-called “last resort” to augment general safety systems.

Accordingly, there is provided a synchronized brake apparatus, comprising: a first emergency safety brake; a second emergency safety brake; a first cable release member; a second cable release member; a first resilient trigger member; a second resilient trigger member; a cable network interconnecting the first cable release member, the second cable release member, the first resilient trigger, the second resilient trigger, the first emergency safety brake, the second emergency safety brake, the cable network being configured such that: i) in response to a braking signal received at the first cable release member, a first tension threshold in the cable network between the first cable release member and the second resilient trigger member decreases so as to activate a first brake.

In one example, the apparatus further includes the cable network interconnecting the first cable release member, the second cable release member, the first resilient trigger, the second resilient trigger, the first emergency safety brake, the second emergency safety brake, the cable network being configured such that: ii) in response to the braking signal received at the first cable release member, a second tension threshold in the cable network between the second cable release member and the first resilient trigger member decreases so as to activate a second brake.

In one example, each of the first and second cable release members includes a toothed activation wheel fixably connected to an interior portion of a brake drum to receive the brake signal. Each of the first and second cable release members are in communication with the toothed activation wheel, each having first and second arms hingeably connected to each other, the cable release member being slidably mounted in a guide slot located in a guide plate to permit movement of the cable release member along a restricted path of travel relative to the toothed activation wheel. Each of the first and second trigger rods are moveably connected to the support plate and in communication with the first and second arms, the first and second trigger rods being moveable relative to the toothed activation wheel.

In one example, the cable network includes i) first and second brake activation signal cables connected to the first and second cable release members to send the braking signal thereto.

In another example, each of the first and second resilient trigger members, the brake cable having a tension threshold that is modified to permit movement of the cable release member between a default configuration and a braking configuration. Each of the resilient trigger members has a second brake cable with a second tension threshold, the second brake cable being in communication with the toothed activation wheel, the resilient trigger member having a top trigger rod extending from the resilient trigger member towards the interior portion of the brake drum. In one example, the first and second resilient trigger members includes a hammer rod, a compression spring and a trigger rod release hingeably mounted on a resilient trigger support plate. Tthe first and second arms include i) a hinge point, the first and second arms being hingebly moveable about the hinge point; and ii) a rod contact portion disposed towards the toothed activation wheel. The first and second trigger rods are connected to a plate spacer, the plate spacer being mounted around the toothed activation wheel and orientated to permit movement of the trigger rods relative to the toothed activation wheel, the first and second trigger rods each having first and second contact tips, the first contact tips each being disposed to contact the toothed activation wheel, the second contact tips each being disposed to contact the rod contact portion of the first and second arms.

In one example, in a first configuration the detector cable is under tension, the first and second arms rest within the toothed wheel teeth contact zone, the rod contact portion of the first and second arms being in contact with teeth grooves, disposed them away from the triggers.

In one example, in an intermediate configuration the detector cable is partially tensioned the first arm being hinged away from the first trigger, the second arm trigger rod are hinged away from the toothed wheel in a V-shaped configuration, the second trigger rod being disposed away from the toothed wheel displaced by the rotation of the toothed wheel.

In another example, in a braking configuration the detector cable is tension free, the first and second arms being hinged away from the toothed wheel in a V-shaped configuration, the first and second trigger rods being disposed away from the toothed wheel displaced by the rotation of the toothed wheel.

In still another example, the apparatus is configured for use in vertical transporting machines including but not limited to load-carrying elevators hoists.

Accordingly in another embodiment, there is provided a braking apparatus, comprising: a toothed activation wheel fixably connected to an inner portion of a brake drum; a cable release member mounted on a support plate on an exterior portion of the brake wheel, the cable release member being in communication with the toothed activation wheel triggers and rods system, and having first and second arms hingeably connected to each other, the cable release member being slidably mounted in a guide slot located in a guide plate to permit movement of the cable release member along a restricted path of travel to the toothed activation wheel; first and second trigger rods moveably mounted in the support plate and in communication with the first and second arms, the first and second trigger rods being moveable relative to the toothed activation wheel; and a brake cable connected to the cable release member and located to send a brake activation signal, the brake cable having a tension threshold that is modified to permit movement of the cable release member between a default configuration and a braking configuration.

In one example, the apparatus further including a resilient trigger member mounted on the exterior portion of the brake drum, and having a second brake cable with a second tension threshold, the second brake cable being in communication with the toothed activation wheel, the resilient trigger member having a top trigger rod extending from the resilient trigger member towards the interior portion of the brake drum.

In one example, in which is configured for use in vertical transporting machines including but not limited to load-carrying elevators hoists.

Accordingly, in another embodiment, there is provided a method for activating a synchronized brake apparatus, the method comprising: interconnecting a cable network having first and second cable release members, first and second resilient triggers, and first and second emergency safety brakes; transmitting a braking signal to the first cable release member; and decreasing a first tension threshold between the first cable release member and the second resilient trigger member, thereby activating a first brake. In one example, the method further includes: interconnecting the cable network having first and second cable release members, first and second resilient triggers, and first and second emergency safety brakes; transmitting the braking signal to the first cable release member; and decreasing a second tension threshold between the second cable release member and the first resilient trigger member, thereby activating a second brake.

In one example, each of the first and second cable release members includes a toothed activation wheel fixably connected to an interior portion of a brake drum to receive the brake signal.

In one example, each of the first and second cable release members are mounted on a support plate on an exterior portion of an encasing casting.

In yet another example, each of the first and second cable release members are in communication with the toothed activation wheel, each having first and second arms hingeably connected to each other, the cable release member being slidably mounted in a guide slot located in a guide plate to permit movement of the cable release member along a restricted path of travel relative to the toothed activation wheel.

In yet another example, each of the first and second trigger rods are moveably connected to the support plate and in communication with the first and second arms, the first and second trigger rods being moveable relative to the toothed activation wheel.

In one example, the cable network includes first and second brake activation signal cables connected to the first and second cable release members to send the braking signal thereto. Each of the first and second resilient trigger members, the brake cable having a tension threshold that is modified to permit movement of the cable release member between a default configuration and a braking configuration. Each of the resilient trigger members has a second brake cable with a second tension threshold, the second brake cable being in communication with the toothed activation wheel, the resilient trigger member having a top trigger rod extending from the resilient trigger member towards the interior portion of the brake drum.

In one example, the first and second resilient trigger members includes a hammer rod, a compression spring and a trigger rod release hingeably mounted on a resilient trigger support plate. The first and second arms include i) a hinge point, the first and second arms being hingebly moveable about the hinge point; and ii) a rod contact portion disposed towards the toothed activation wheel. The first and second trigger rods are connected to a plate spacer, the plate spacer being mounted around the toothed activation wheel and orientated to permit movement of the trigger rods relative to the toothed activation wheel, the first and second trigger rods each having first and second contact tips, the first contact tips each being disposed to contact the toothed activation wheel, the second contact tips each being disposed to contact the rod contact portion of the first and second arms.

In another example, in a first configuration the detector cable is tension free, the first and second arms being hinged away from the toothed wheel in a V-shaped configuration, the rod contact portion of the first and second arms being in contact with the first and second trigger rods, which are disposed away from the toothed wheel because of the toothed wheel rotation.

In another example, in an intermediate configuration the detector cable is partially tensioned so that the first arm rests within the teeth area, and from the second arm, the second trigger rod is hinged away from the toothed wheel in a V-shaped configuration, the second trigger rods being disposed away from the toothed wheel because of the toothed wheel rotation.

In still another example, in a braking configuration the detector cable is tension free because the first and second arms are hinged away from the toothed wheel in a V- shaped configuration, the first and second trigger rods being disposed away from the toothed wheel because of the toothed wheel rotation.

In yet another example, the method is configured for use in vertical transporting machines including but not limited to load-carrying elevators hoists. BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of that described herein will become more apparent from the following description in which reference is made to the appended drawings wherein:

Fig. i is a perspective front view of a car showing the location of a brake synchronization apparatus, the view showing a panel removed for ease of viewing:

Fig. 1A is a perspective close-up view of the brake synchronization apparatus mounted inside the car of Fig. i;

Fig. 2 is a perspective outside rear view of the car of Fig. i showing the location of a plurality of gear wheels;

Fig. 2 A is a close-up perspective view of the plurality of gear wheels of Fig. 2;

Fig. 3 is a perspective view of an embodiment of a brake synchronization apparatus with an exploded view of a trigger mechanism;

Fig. 4 is an exploded perspective view of an embodiment of a brake drum showing a brake activator;

Fig. 5 is a close-up view of a cable release member with trigger rods engaging a toothed activation wheel;

Fig. 6 is a close-up view of a cable release member with trigger rods partially engaging a toothed activation wheel;

Fig. 7 is a close-up view of a cable release member with trigger rods disengaged from a toothed activation wheel;

Fig. 8 is a close-up view of a cable release member with trigger rods fully disengaged from a toothed activation wheel;

Fig. 9 is a perspective view of a trigger mechanism showing a detector cable with tension removed; Fig. 10 is a perspective side view of the apparatus showing the trigger mechanism with a hammer rod and spring holder in a released configuration with the trigger rods engaging the toothed activation wheel;

Fig. 11 is a plan view of two brake drums with brake cables interconnecting the trigger mechanism and the cable release member;

Fig. 12 is a close-up perspective view of the trigger mechanism;

Fig. 13 is a side view of the trigger mechanism of Fig. 12;

Fig. 14 is a rear view of the trigger mechanism of Fig. 12;

Fig. 15 is a side view of the trigger mechanism showing movement (arrow) during a braking operation;

Fig. 16 is a rear view of the trigger mechanism showing movement (arrow) during the braking operation;

Fig. 17A illustrates Step 1 of a safety device dual activation sequence in which a governor hammer activation includes a hammer being pushed out by a centrifugal force past a rotation speed threshold;

Fig. 17B illustrates Step 2 of the safety device dual activation sequence in which drum rotation and dual mechanism trigger involves brake drum and activation wheel is driven by the governor hammer and thereafter constant pressure is applied to the brake cable so that both rods are activated which triggers the release of the brake cable;

Fig. 17C illustrates Step 3 of the safety device dual activation sequence (Brake cable mechanical signal) in which a first safety device is activated to trigger the brake cable thus causing pulling on the second safety device which triggers the second safety device top trigger. Pressure from the cable is released and the spring-loaded rod is pulled; and

Fig. 17D illustrates Step 4 of the safety device dual activation sequence (Top trigger activation) in which a top trigger rod releases the governor within the second safety device in the direction of the arrows. DETAILED DESCRIPTION

Definitions

Unless otherwise specified, the following definitions apply:

The singular forms “a”, “an” and “the” include corresponding plural references unless the context clearly dictates otherwise.

As used herein, the term “comprising” is intended to mean that the list of elements following the word “comprising” are required or mandatory but that other elements are optional and may or may not be present.

As used herein, the term “consisting of’ is intended to mean including and limited to whatever follows the phrase “consisting of’. Thus, the phrase “consisting of’ indicates that the listed elements are required or mandatory and that no other elements may be present.

Addressing calibration inaccuracies were key during our trial-and-error design process. We built a construction hoist that was oversized and outside of the standard dimensions scope. However, the device we created generally weighed more than the maximum capacity of the strongest safety device currently available on the market. Based on this, we had a number of design options available to us. We could manufacture our own in-house safety device, capable of meeting the strength requirement; we could modify existing third-party safety devices to meet the strength requirement; or we could use more than one safety device to share the load between them.

We carried out overloaded drop tests to characterize our safety device as well determine the effect this had on the integrity of the rack and pinion teeth. We learned the physical limits and breaking behavior of part overloaded. After these tests, we concluded that we couldn’t merely strengthen the safety device. The strengthened safety device would simply transfer the effort to the rack and pinion teeth, and teeth would become a weak point of the system. Moreover, we couldn’t modify the teeth size to meet these new loads. Because of this, we believed we could share the load between two or more safety devices. In addition to limiting the strain on the safety devices it would also divide the load between more rack and pinion teeth. Finally, to share the load efficiently, all the safety devices needed to activate simultaneously with minimal delay so as to reduce the amount of load applied to the brakes. Two braking safety devices are typically used in our new system.

Referring now to Figs. 1, 1A, 2 and 2A, first and second safety devices 12, 12A are modified and installed on a lifting apparatus (also known as a “car”) 13. The safety devices 12, 12A are mounted in a frame 15. The safety device 12, 12A are each in communication with a plurality of axially rotatable gear wheels 17 mounted in a rear portion 19 of the car 13.

Referring now to Figs. 3, 4, and 11, there is shown generally at 10, a synchronized braking system that is an add-on feature for use with a safety device 12. Since the braking system typically uses two, essentially identical safety devices 12 and 12A, only one will be described in detail. The safety device 12 includes a top, resilient trigger mechanism 14 mounted on a top portion of the safety device. The mechanism 14 is mounted on a top trigger mechanism support plate 16 and includes a top trigger rod 18, top trigger compression spring 20, and a trigger rod release 22. The top trigger rod 18 is threaded through a modified M16 bolt 24 for location into a mechanism housing 26. A brake activation detector 28 is mounted on an exterior portion 30 of the safety device exterior casing 32 and extends into the interior of the exterior casing 32. A brake activator signal cable 34 is connected to the brake activation detector 28. Furthermore, the safety device drum and toothed wheel assembly 36, as best seen in Fig. 4, provides a one-piece portion. The drum and toothed wheel assembly 36 is generally conical-shaped which rotates inside the casing 32 and presses against a brake pad during a braking operation.

Turning now to Figs. 4, 5 to 8, and Figs. l Ato 17D, the safety device drum 36 includes a toothed activation wheel 36 that is fixedly welded to the interior of the safety device drum 36. An activation detector cable release member 38 includes first and second arms 40, 42 that are hingeably connected to each other about a hinge point 68. Specifically in Fig. 17B, the ghosted image (dotted lines for ease of illustration) illustrates the drum 36 welded to the toothed wheel. The cable release member 38 also includes first and second detector trigger rods 46, 48, and an assembly plate spacer 50. The trigger rods 46, 48 are slidably mounted in the assembly plate spacer 50. The assembly plate spacer 50 serves two purposes. First, to compensate for the added thickness the toothed activation wheel 36 adds, and second, to hold the brake activation detector cable release member 38 so that it is aligned with the first and second detector trigger rods 46, 48. A centrifugal mass boosterplate 52 is located in between the centrifugal mass 56 and the safety brake housing plate (not numbered) so as to raise the centrifugal mass to the original drum level. A modified brake shaft 58 is mounted on an outer ring support plate (not shown) and holds a hammer rod 60 and a resilient spring member 62. The hammer rod 60 and spring member 62 are disposed generally orthogonal relative to a safety device drum axis 64.

As best seen in Figs. 5 through 8, the first and second arms 40, 42 include a hinge point 68 so that the first and second arms 40, 42 can hingeably move thereabouts. The hinge point 68 is mounted on a "slotted" cylinder 73., with the cylinder 73 being fitted outside of the plate spacer 50 for guiding the hinge point 68 therealong on a restricted path of travel 73. The first and second trigger rods 46, 48 are connected to the plate spacer 50, which is mounted around the toothed wheel 36 and orientated to permit movement of the trigger rods 46,48 relative to the toothed wheel 36 (see arrows). The first and second trigger rods 46, 48 each have first and second contact tips 70, 72. The first contact tips 70 are each disposed to contact the toothed activation wheel 36. The second contact tips 72 are each disposed to contact a rod contact portion 79 of the first and second arms 40, 42.

The operation of the cable release member is shown specifically with reference to Figs 5, 6, 7 and 8. Referring specifically to Fig. 5, in a default configuration the detector cable is tension free so that the first and second arms 40, 42 are hinged away from the toothed wheel to achieve a V-shaped configuration.

Referring specifically to Fig. 6, in a first configuration, the detector cable 34 is under tension. Figure 7 shows the configuration in which the cable tension is removed, and finally in Figure 8, the system shows the configuration after tension is removed. Specifically in Fig. 8, the first and second arms 40, 42 are hinged away from the toothed wheel 36 in a V-shaped configuration. The rod contact portion 79 of the first and second arms 40, 42 are in contact with the first and second trigger rods 46, 48, which are disposed away from the toothed activation wheel 36 thereby removing the tension from the cable.

Referring specifically to Fig. 7, in an intermediate configuration, the detector cable 34 is partially tensioned so that the first arm 40 is hinged away from the second arm 42. The second trigger rod are hinged away from the toothed wheel in a V-shaped configuration. The first and second trigger rods 46, 48 are configured in such a way that if the toothed activation wheel 36 rotates, the trigger rods 46, 48 will move away therefrom.

Referring specifically to Fig. 8, in a braking configuration, the detector cable is tension free and has been pulled by the second brake spring loaded top trigger mechanism trigger mechanism so that the first and second arms are hinged away from the toothed wheel in a V-shaped configuration.

Referring again to Figs 5 through 8, and now Figs. 10 and 11, one of the two safety devices 12 will activate first, upon activation the brake drum and its welded activation wheel 36 will start turning, so as to trigger the activation trigger rods 46, 48. After the rods have triggered the two detector cable releases 40, 42, it cancels tension over the detector signal cable of the second brake. The signal of activation (tension removed from the cable) is sent from the first safety device 12 to the second safety device 12A, a top trigger release occurs almost simultaneously, allowing the spring 20 to trip the detector and pull on the rod 18.

As best seen in Fig. 11. generally speaking, the first and second emergency safety brakes 12, 12A are denoted to permit their description. This description in no way implies that one emergency brake is “first” operated followed by a “second” emergency brake. The qualification "first" could apply to any of the brake activating first. Similarly, the qualification "second" would apply to the brake that is being tripped by the first. Due to the design of the system, there is no way to control which brake will trip first. In a first scenario, the device on top trips first and sends a signal from the side cable release to the second brake top trigger. In a second scenario, the same would apply, but in this case from the lower brake prescriptive. Referring now to Figs, 4, 9 and 10, upon signal (removal of the cable tension), the second brake top trigger release 22 is pushed by the top trigger compression spring 20. this pulls on the top trigger rod 18. when the top trigger rod is pulled, it releases the hammer rod 60 and spring holder spring within the centrifugal mass at the center of the brake so that the hammer 22 becomes free of tension. Under this condition the second safety devices will automatically activate due to the released hammer now driving the drum, and due to the downward movement of the machine. In this condition rotation speed becomes irrelevant and the slightest movement of the centrifugal mass activates the hammer release.

Referring now to Figs. 1, 1A, 2, and 17A through 17D, first and second safety devices 12, 12A are modified and installed on a lifting apparatus (also known as a “car”). A set of brake cables 34 connects the top trigger mechanisms and brake activation detectors of each safety device 12, 12A. To complete the installation, brake activation signal cables in which one cable tip assembles to the brake activation detector (sending signal) and theother tip assembled to the top trigger mechanism (receiving signal), with two cables 34 linking both safety devices in a “criss-cross” fashion, as best seen in Fig. 17C any of brake activating first will signal the other one to activate simultaneously in a matter of fraction of second.

Referring to Fig. 17A, Step 1 in an activation operation involves a governor hammer activation using a governor module 99. A hammer 100 is pushed out by the centrifugal forces acting thereon, which exceeds a rotation speed threshold. Axial rotation about a pinion gear shaft 102 is illustrated by the arrows 104.

Referring to Fig. 17B, Step 2 of the activation operation involves drum rotation and dual mechanism trigger. Specifically, a brake drum 106 (dotted line item) and an activation wheel 36 are driven by the governor hammer 100. Constant pressure is applied to the brake cables 34. One of the two rods in the plate will push on one of the latches to release a pin that is linked to the cable end.

As illustrated in Fig. 17C Step 3 of the activation operation involves a brake cable mechanical signal. The first safety device 12 that is activated triggers the brake cable 34 which pulls on the second safety device 12A. This then triggers the second top trigger so that pressure from the cable 34 is released. The spring-loaded top rod is then pulled, is under tension due to the spring load located at the other end of the cable. Without any tension anymore, the spring-loaded application from the top trigger of the opposite brake will trip, lifting a rod that moves through the second brake, all the way inside.

As illustrated in Fig. 17D, Step 4 of the activation operation involves a top trigger activation. By pulling on the rod this then removes the restriction for activation inside the second brake. As noted above, this removes the restriction to the hammer, and the slightest rotation of the system will engage the hammer to the drum. In short, it cancels the restriction of the small spring 62, as shown on Fig. 4. that normally fight against the centrifugal force.

Thus, in summary, the braking system can be described as a synchronized brakes apparatus. The system includes a first brake, a second brake, a first cable release member, a second cable release member, a first resilient trigger member and a second resilient trigger member. To operate the system, a cable network is designed to interconnect the first cable release member, the second cable release member, the first resilient trigger, the second resilient trigger, the first brake, and the second brake. As best seen in Figs. 3 through 6, and 9, the cable network is configured so that a braking cable network connects between the first cable release member and the second resilient trigger member decreases so as to activate a first brake. Simultaneously, the cable network interconnects the first cable release member, the second cable release member, the first resilient trigger, the second resilient trigger, the first brake, and the second brake. The cable network is configured such that in response to the braking signal received at the first cable release member, a second tension threshold in the cable network between the second cable release member and the first resilient trigger member decreases so as to activate a second brake.

All the above steps happen in fraction of second. Because of this we can affirm that both safety devices 12 and 12A activate at the same time, thereby efficiently sharing the braking timing and braking load.

After the safety devices activation, both safety devices must be reset manually, as well as all release components of the synchronized braking system. Testing results

As part of our system’s development, we subjected a number of designs to a plurality of performance and stress tests to determine the optimal design features.

Phase i - Initial overloading test:

During Phase 1, we tested the reaction of our SAJ-60 safety device in its typical usage (a single safety device) by overloading a lifting unit and performing drop tests. A drop test is a controlled free fall of a lifting equipment. All machine design codes request that periodic drop test be performed under specific conditions, which are a) time period; b) testing weight; c) within a certain activation speeds range; and d) within a certain MIN and MAX retardation.

We applied our in-house rules and code compliance requirement to experiment under a so-called “worst possible case” scenario. Thus, the test was carried out as follows:

In this scenario, 125% of the rated load + additional weight of an oversized machine = 8 750 lbs + 1250 lbs = 10 000 lbs test load

We must also consider the machine weight = 9 085 lbs.

This brings us to a total of 19 085 lbs total test weight, which greatly exceeds the maximum load of 17636 lbs allowed for a SAJ-60 type brake.

Under these conditions multiples failures occurred: a) The assembly plate bent; b) the safetydevice plate broke in two; and c) the safety device gear tooth and rack tooth broke.

Based on this, we concluded, after the end of Phase 1 we took the decision of developing a system that could use 2 brakes at the same time.

Phase 2 - Design iterations:

During Phase 2, after much trial and error, we brainstormed ways to servo 2 safety devices.

Phase 3 - Synchronized system test: The design 3 shown in previous phase 2 was built as a prototype of a synchronized apparatus for testing. We were ready to simulate the drop test with the same conditions that failed on phase 1. After the test, there were no failure of the brake original parts, assembly plates, nor any rack or pinion tooth. The top trigger rod release warped due to the impact speed of the spring. That part will be reinforced in the final revision of the designed. The activation detector releases components warped a bit too and needed to bereinforced as well.

The hammer and spring rod holder design was optimized to facilitate the top rod engage, the general assembly, and its sliding property. Other Embodiments

From the foregoing description, it will be apparent to one of ordinary skill in the art that variations and modifications may be made to the embodiments described herein to adapt it to various usages and conditions.