Description

Technical Field

[0001 ] The invention relates to a twisting machine with internal pay-off spools, more specifically a bunching or cabling machine, more specifically a machine for twisting steel wires around one another. The machine is particularly intended to produce steel cord. The machine has a spool carrier that can be easily exchanged. The carrier replaces the conventional spool cradle.

Background Art

[0002] Twisting machines such as bunching machines or cabling machines are used to twist filaments around one another resulting in a cord. To do this in an efficient way spools with filament are mounted on one or more stationary cradles and the wires are rotatably led over the spools either by a drum or a flyer while the twisted filaments are pulled through by a capstan.

[0003] In the case of cabling one turn of the drum or flyer in combination by the pulling of the filaments results in a single lay of the required lay length. The lay length in meter is then the ratio of the linear velocity (in meter per minute) over the angular velocity (in turns per minute). In cabling the filaments are not torqued in the process.

[0004] In the case of bunching the filaments obtain two twists per turn of the drum or flyer and the filaments themselves are also torqued one turn per lay length. It follows that the bunching process is the preferred process as the productivity is in principle the double of that of the cabling process.

[0005] The process of cord making thus involves a lot of spool handling and threading the filaments through the twisting machines. When the machine was already loaded the threading effort can be reduced by connecting - e.g. by knotting - the end of the filaments of the previous load to the beginning of the newly loaded full spools. Only in the case the machine has to be threaded for the first time, filaments have to be lead through the complete machine. [0006] For example for producing a 3+9+15 type of cord that is made by:

- first loading three spools in a twisting machine, subsequently doffing the resulting 3x1 core spool,

- next load the 3x1 core spool to the outside position of a subsequent twisting machine that is loaded with 9 inside spools and twisting the 9 filaments around the 3x1 core resulting in a 3+9 that is wound on a core spool;

- next load the 3+9 core spool to the outside position of a subsequent twisting machine that is loaded with 15 inside spools and twisting 15 filaments around the 3+9 core resulting in a 3+9+15 cord.

In this simple example already 29 spool loadings and 3 doffing actions are needed.

[0007] The threading and loading of the machines is a tedious and laborious action as the spools are heavy and bulky. Moreover attention is needed when threading the machine as the wire path must be well observed in order not to obtain defective product e.g. by exchanging filaments. Further, to save space for the filament spools - bigger filament spools run longer hence are more productive - the remaining space for the wire path has decreased and it becomes more difficult to thread the filaments through the narrow alleys in between the spools.

[0008] The disclosure GB1343471 describes a system to enhance the productivity of loading by mounting two or more spools on a carrier that is locked to a cradle. The suggested apparatus is simple and straightforward but does lack essential features and is also not safe in use.

[0009] The inventors have further studied this rudimentary idea which resulted in a working and safe twisting machine that will be described hereinafter.

Disclosure of Invention

[0010] The main object of the invention is to improve the ergonomics and safety of the spool loading of a twisting machine. To that end an apparatus - the twisting machine - and a method of operating the twisting machine is disclosed. Another objective of the apparatus is to improve the productivity and uptime of twisting machines. [0011 ] According a first aspect of the invention a twisting machine as described by the preamble of claim 1 is provided.

[0012] The twisting machine has an internal pay-off of filaments meaning that the filament spools are stored within the space defined by the rotating drum, flyer or filaments and the filaments move outside this space during cord production. The cord is wound on a spool outside this space. This in contrast with an outside-in, or internal buncher where the cord is wound on an internal take-up spool within the space defined by the rotating filaments of flyer.

[0013] The twisting machine comprises a bridge that is rotatably mounted between a first and second rotor. The first and second rotor are co-axially mounted and driven by a motor in the same direction and at the same speed and define a rotor axis. The first and second rotor maybe connected by a drum or a flyer for guiding the filaments from the first rotor to the second rotor. Alternatively, also known as a twisting machine without flyer, the first and second rotor may comprise filament guides that hold the filaments away from the bridge while the filaments rotate and move unsupported from the first rotor to the second rotor. The bridge connects between the first and second rotor, but as it is rotatably mounted to the first and second rotor, it remains stationary during the running of the twisting machine. The bridge is heavy enough to remain at the lower position by gravity action as the rotors are rotating.

[0014] The twisting machine further comprises a carrier for mounting pay-off spools on. The carrier can be mounted onto the bridge and it can be dismounted from the bridge. The bridge holds and bears the carrier.

[0015] The carrier is provided with all necessary ancillaries to dynamically unwind the spools and to guide and handle the filaments. The carrier therefore is provided with spool spindles or axles for unwinding the spools, with path control means to guide the wire through the carrier and with tension control systems to control the tension of the filaments as delivered from the spools. Depending on the need the carrier can be equipped with two or more e.g. three, four,.. possibly up to fifteen spindles or more. Alternatively the carrier can be equipped with a single spindle. A single spindle carrying one spool with two or more parallel wound filaments can be produce a cord.

[0016] The wire path control means can for example but not exclusively be a pay off roll, deflecting pulleys, brake pulleys, wire separation pulleys, distribution discs, preformers or equivalent parts.

[0017] A pay off roll is a roll that is mounted parallel to the spool axis and extends over at least part of the winding width or over the full winding width of the filament. It serves to evenly unwind the wire from the spool.

[0018] The deflecting pulleys may serve to guide the filament wire through the carrier. Brake pulleys are also present on the tensioning arms of the pendulum brakes, where they interact with the deflecting pulleys to actuate the pendulum actuated brakes. Deflecting pulleys remain fixed to the carrier, brake pulleys are mounted on the brake lever and move with the lever. Wire separation pulleys may be brought into the wire path when spools are used that carry two or more filaments wound parallel. The wire separation pulleys serve to separate the closely wound filaments.

[0019] A distribution disc helps to position the individual filaments prior to entering the assembly point. Preformers are devices that impose on the filament a degree of curvature. In combination with a rotating filament, this results in a filament that has the correct helix shape before entering the cabling die. The cabling die is the assembly point where all filaments meet and are held together before being twisted together.

[0020] The tension control system comprises pendulum actuated brakes, brake disks, brake levers, tension springs, brake bands or brake chains. The brake disk can rotate and is fixedly connected to the rotating wire spool. A brake band or brake chain is tensioned against the brake disk by means of a tension spring. A brake band has one single contact area in common with the brake disk, while a brake chain has periodically spaced brake blocks having multiple contact areas with the brake disc. The other end of the brake band or brake chain is connected to the shorter arm of a lever. The lever rotates around a fulcrum attached to the carrier. The longer arm of the lever connects with the brake pulleys. A pendulum actuated brake adapts the braking torque exerted on the brake disk by sensing the tension on a filament loop wound from a deflecting pulley to the brake pulley by exerting more or less tension on the brake band or brake chain. Possibly one, two or more loops can be formed between the brake pulleys and the deflecting pulleys, thereby increasing the braking torque by making use of the block-and-tackle effect.

[0021 ] According one preferred embodiment of the invention, the number of spool spindles on the carrier below the horizontal plane comprising the rotor axis is one or more than the number of spool spindles on the carrier above the horizontal plane. For example, there may be 2 spindles above the horizontal plane and 3 below, or 2 above and 4 below. This is irrespective whether or not the carrier is - during operation - horizontally or vertically oriented: this does not matter. This arrangement ensures a low enough center of gravity for the carrier such that safe positioning of a fully loaded carrier or the safe removal of an emptied carrier always has the centre of gravity sufficiently low. However, for ease of transport, loading and unloading, the carrier is preferably mounted vertically.

[0022] According a further preferred embodiment of the invention, the carrier is build up of a base plate and first and second ancillary plates for mounting at least part of said path control means or tension means on. The plates are mounted symmetrically to the sides of the base plate (left and right), and cover part of the base plate. Preferably the carrier is mounted vertically and first and second ancillary plates help to keep the centre of gravity low.

[0023] According a further preferred embodiment of the invention, the carrier is provided with a first and second shoulder. The shoulders are situated at the outer region, circumference of the carrier. The bridge is provided with a first and second recess wherein the associated first and second shoulder fit, are received, are carried, are held when the carrier is mounted in the twisting apparatus. This first and second recess are positioned close to the first and second rotor. The centres of the first and second rotors share the same axis. The distance along said axis from the first to the second rotor will be called the ‘bridge span’. In case of dispute: this bridge span is to be taken between the races of the bearings of the first and second rotor closest to one another. The races of those closest bearings are the points of reference for any distances along this axis hereinafter.

[0024] The axial distance, that is the distance as taken between perpendiculars to the axis of the rotors, between the first rotor and the first recess must be smaller than a third of the bridge span. Even more preferred is if this axial distance is smaller than one fourth, one fifth or even one tenth of the bridge span. Mutatis mutandis the axial distance between the second rotor and the second recess must be smaller than one third, one quarter, one fifth or even one tenth of the bridge span. For the avoidance of doubt: the axial distance between first rotor and first recess must not necessarily be equal to the axial distance between second rotor and second recess, although equality is for symmetry reasons somewhat preferred. For the avoidance of doubt: as the recesses will of course have some axial extend, the shortest possible axial distance between the point of reference of the rotor and the recess is to be considered.

[0025] The inventor has found that by resting the carrier at those recesses, the bearings on the rotors are less loaded. Contrary to intuition, where one would let the carrier be bom in the middle of the bridge. However, this latter option turns out not to be the best position.

[0026] In a further preferred embodiment the first and second recess receive the recess under an incline, a slope an inclination that is oriented towards the first or second rotor. In other words: the bottom of the recess rises when moving toward the rotor. The angle of the slope or inclination is between 15° to 75°, or even between 20° to 70°, for example 45°. The inclination has the advantageous feature that the shoulders exert a force towards the rotors, outward of the machine. This force helps to compensate the forces that are exerted on the rotors by e.g. the flyers that tend to pull the rotors to one another. In addition, the inclination helps to centre the carrier when loading into the twisting machine.

[0027] In a further preferred embodiment the carrier comprises one, two or more locks comprising a lock body and a lock bolt with corresponding key rod. The lock bolt slides in the lock body. The lock bolt engages, slides into, locks into a lock bolt receiving hole or lock hole on the bridge. The lock bolt locks the carrier to the bridge when the twisting machine is operative. The key rod must be in the lock bolt when the carrier is not locked to the bridge. The presence of the key rod is a clear indication to the operator, that the carrier is in its unlocked position. When the key rod is present, the flyer, drum or filament balloon cannot pass as the key rod obstructs the path of the flyer, drum or filament balloon. Only when the carrier is locked to the bridge, the key rod can be removed.

[0028] Preferably there are two locks: one at either side of the carrier. This adds additional redundancy in that the carrier will not disengage easily from the bridge. Possibly there can be three or four locks.

[0029] In a preferred embodiment the key rod is received by the lock bolt when the lock bolt is in a first position. Only then the lock bolt can be moved by the key rod to a second position. When the lock bolt is in the second position, the key rod cannot be removed. Only if the key rod is brought back to the first position, it can be removed. In the second position the lock bolt is held in position by the key rod. The first position of the lock bolt corresponds to the situation wherein the carrier is locked to the bridge. The second position of the lock bolt is the situation wherein the carrier is freed, unlocked from the bridge. The carrier can then be removed from the twisting machine.

[0030] The lock bolt must be securely held, engaged in the lock hole i.e. in the first position when the twisting machine is operative. That is when the key rod is removed. This can be achieved in a number of ways. The lock bolt can be pushed into position by a mechanical spring pushing the lock bolt into the lock hole. In an alternative embodiment, the lock bolt can be pushed into position by an air spring. In another embodiment, possibly in combination with a mechanical or pneumatic spring, the lock bolt can be held in position by a magnet situated at the bottom of the lock hole.

[0031] In a further preferred embodiment, the carrier is provided with lifting hooks or eyes to lift the carrier out of the machine.

[0032] Particularly preferred embodiments of the twisting apparatus are steel wire twisting machines. In steel wire twisting machines the spools are inherently heavy. Handling of those spools therefore cannot be done by hand and lifting equipment is needed. Particularly in this kind of machines the approach offered by the invention can help to decrease loading time and improve ergonomics.

[0033] The twisting machine is preferably a bunching machine. A bunching machine twists all wires together with torsion. Alternatively the twisting machine can be a cabling machine. Here the filaments coming from the spool will form a bundle of not twisted filaments.

[0034] According a second aspect of the invention a method for loading and unloading of a twisting machine as described here before is presented. The method uses the carriers as described.

[0035] One begins with the provision of an empty carrier outside the twisting machine. This carrier can be in a waiting position or can be taken out of a twisting machine that has run empty. An empty carrier can be a carrier without spools or it can be a carrier with empty spools i.e. spools with possibly a small remainder of wire filament on. The carrier can be positioned on an appropriate stand, in the vertical or horizontal position or any angle in between for easy access.

[0036] Full spools are loaded on the carrier. In the case the carrier is without spools this is easy. When there are still empty spools on the spindles, the empty spools have to be removed. Possibly a filament end from the empty spool can be connected to the filament end of the full spool. The full spools can contain one filament. Alternatively the full spools can contain two, three, four or more filaments wound parallel. So with one single spool more filament lengths can be loaded.

Subsequently the filaments are threaded through the wire path of the carrier, thereby following the wire path control means. When all filaments are properly threaded, they are collected at the one assembly point that is the cabling die. The bundle of filaments exits the cabling die. The key rods are put into the lock bolts and set to the second position. This all happens outside of the twisting machine.

[0037] The threaded carrier can be transported - possibly by an automated transport vehicle - to the vicinity of the twisting machine. It is then mounted into the empty twisting machine. The carrier is locked to the bridge by means of the lock bolt that is set to the first position and only then the key rods can be removed. The key rods are stored at the machine on a dedicated place. An additional security feature is that the twisting machine cannot be started unless all key rods are identified, are detected, are sensed to be present.

[0038] The bundle of filaments leaving the cabling die is connected to the remaining cord end of the previous load. Alternatively, the filament bundle is threaded through the filament path following that is: through the drum or the flyers, and/or through the rotors. The connection is inched through the twisting machine. Once the connection is on the take up spool, the connection is cut out and the twisting machine can be started.

[0039] The method presented allows the carrier to be loaded and threaded in the best possible manner:

- The operator has free access around the carrier. Indeed, the operator does not have to reach into the machine and can simply walk around the carrier to do the threading;

- As there is no flyer or drum that further reduces the space to thread the machines, it is easier for the operator to thread the machine. More space is available for filament threading by hand;

- Loading and unloading of spools can be done more efficient with better lifting equipment. Less lifting equipment is needed as the loading of the carrier can be done in a centralised space, under agreeable working conditions. Not every machine has to be provided with a hoist.

- Adjustment of pay-off tensions can be done outside the twisting machine, which improves the uptime of the machine and the precision of the adjustment.

- Supply of full spools can be made easier, as the spools arrive in one centralised area and do not have to be brought to the machines. Empty spools are also collected at a centralised place.

- The threaded carriers can be queued and brought to the machine in a just-in-time manner. - The carriers can replace the many transporting pallets needed to transport spools.

By this novel way of working intermediate transport can be reduced, the up-time of twisting machines can be increased, but above all working conditions for operators can be greatly improved.

[0002] Preferably the ‘threading area’ is situated between the area for drawing the filament and the areas were twisting machines are present, in a dedicated zone. This dedicated zone can be easily airconditioned, can be silent, well lit, in short: more agreeable to work in.

Brief Description of Figures in the Drawings

[0003] Figure 1 shows on overview of the twisting machine according the invention.

[0004] Figure 2 shows the carrier and the bridge according the invention. [0005] Figure 3 shows the perspective view of the lock bolt and the key rod. [0006] Figures 4a, 4b, 4c show the working of the lock bolt.

[0007]

[0008] The hundred digit of the reference number refers to figure number. Equal unit and ten digits refer to like items across figures.

Mode(s) for Carrying Out the Invention

[0009] Figure 1 shows a perspective view of a twisting machine 100 - in this case a bunching machine with flyers - wherein the invention is implemented. The twisting machine has a housing 102, two rotors 104, 104’ connected by two symmetrically mounted flyers 106 (one is not visible) that guide the filaments or the cord from one rotor to the other. The rotors 104, 104’ are rotatably driven by a motor (not shown) and carried by outer bearings (not shown) in a manner known to the skilled person. The bridge (not visible) is mounted rotatably in between the rotors 104, 104’ by means of inner bearings (not shown) situated in the rotors 104, 104’. The twisting machine 100 has the filament spools 190 (only one indicated) mounted on the inside, that is: the spools are within the space defined by the rotating flyers 106. In this machine six spools can be accommodated: three on the front, and three at the back of the carrier. The number of spindles below the horizontal plane through the rotor axis is 4 while the number of spindles

RECTIFIED SHEET (RULE 91 ) ISA/EP above the horizontal plane is 2. This ensures that the center of gravity remains sufficiently low and the carrier remains stable during loading and unloading. The twisting machine is provided with the known features such as a take up unit, control unit, motors, and so forth. These features are known per se by the skilled person and are not detailed in the figures.

[0048] Figure 2, the top section shows the empty carrier 201 , the lower section shows the bridge 250 for receiving the carrier 201 . The carrier is provided with three spindles 202, 202’, 202” on one side. As in this embodiment the plane of the carrier is vertical, three other spindles (not visible) can be arranged at the other side, in mirror arrangement. So in total six spindles are present, whereon the six spools can be mounted. If each of the six spools contain two filaments, the carrier allows to wind off twelve filaments in one load.

[0049] Clearly this amount of filaments must be guided through associated wire path control means. To this end the carrier comprises six pay-off rolls of which three 208, 208’, 208” are visible and three are on the back side of the carrier. These pay-off rolls 208, 208’, 208” will ensure appropriate unwinding from the filament over the width of the spool. The filament pursues its course over a number of deflecting pulleys, of which one is indicated 210, and one or more loops are made between the deflecting pulley 210 and brake pulley 212.

[0050] When focussing on the front, right, lower spindle 202, this spindle is fixed to a brake disc 216 on which a brake chain 218 runs. The brake chain 218 is tensioned by a tension spring (not visible) and a lever 214 that is pulled by tension pulley 212. The brake disc 216 fixedly rotates with the spool and puts tension on the filament while unwinding. These items form a tension control system attached, integrated with the carrier. The system is build up in the same manner for each other spool position on the carrier 201.

[0051 ] Ultimately - after being properly arranged through a distributor disc 220 and one or more preformers (not shown) - the bundle of filaments converges into a cabling die held in a cabling die holder 222. The cabling die provides a fixed cabling point. [0052] All these items are fixed to a base plate 224 and a first and second ancillary plate 226, 226’. The first and second ancillary plates 226, 226’ are used to mount some diverting pulleys on. These ancillary plates 226, 226’ also ensure that the carrier remains vertical during use. The base plate 224 of the carrier is further provided with a first 228 and second shoulder. Only the first shoulder 228 is visible on Figure 2, the other shoulder being present at the other, not visible end. The carrier 201 is further provided with a lock with associated key rod indicated 240. This will be further discussed in detail. The carrier 201 is also provided with two eye bolts 230, 230’ for lifting the carrier out the twisting machine 100.

[0053] The bridge 250 has two bore holes 252, 252’ wherein the inner bearings (not shown) are held. The bridge 250 has two legs 254, 254’, and a heavy plateau part 256 for keeping the centre of gravity low. On the legs 254, 254’ towards the bore holes 252, 252’ a first 258 and second 258’ recess is provided. This first shoulder 228 engages with a first recess 258, the second shoulder in a second recess 258’. 260 indicates the axis of the rotors 104, 104’ centred through the bore holes 252, 252’. The distance between the two rotors 104, 104’ as taken from the races of the inner bearings is the bridge span indicated ‘L’. The axial distance indicated ‘M’ from the second recess 258’ to the second rotor 104’ is about 1/15 of the bridge span ‘L’. The bridge 250 is further provided with two guiding pieces 262, 262’ for guiding the carrier when mounting.

[0054] Figure 3 shows a perspective view of the lock 340 (Figure 2, 240) in detail. Two such locks 240 are present on the carrier 201 , one on each side of the carrier. The lock comprises a lock bolt (not visible) sliding in the lock body 344 and engaging with a lock bolt receiving hole 343. The lock bolt can be moved by means of a key rod 342 as will be explained by referring to Figure 4a, 4b and 4c.

[0055] When the carrier is mounted inside the twisting machine the lock bolt 446 is in a first position. The lock bolt 446 engages with a lock bolt receiving hole 443 in the sides of the guiding pieces 462. The lock bolt 446 is held in its position, pushed into the receiving hole by means of helical spring 448. Alternatively the spring 448 can be a pneumatic spring. Still alternatively or even in addition to the mechanical spring a pneumatic spring can be used. Also can it be helpful to have a countermagnet in the guiding piece 462 that pulls the lock bolt 446 into the receiving hole 443.

[0056] To remove the carrier the operator first must fetch the key rod 442, that is kept in a holder to the twisting machine. The key rod 442 is inserted into hole 450 in the lock bolt 446: Figure 4a. The operator then pulls the lock bolt 446 out of the receiving hole 443 by overcoming the spring 448 force: Figure 4b. When the lock bolt 446 is in the second position, the ‘open position’, the key rod 442 is pushed further into a hole 449 in the lock body 444: Figure 4c. A necking 447 in the key rod 442 passing in a narrowed slot 445 ensures that the key rod cannot be inadvertedly removed from the lock 440 when the carrier is removed from the twisting machine. To put a new carrier in the twisting machine, the actions must be done in the reverse order.

[0057] The loading of a twisting machine is by the use of the here described removable carrier greatly simplified. In stead of having shuttle racks between the filament delivery department and the twisting department, full filament spools can be directly mounted, loaded on the carrier. So the loading of a shuttle rack in the filament delivery department and the unloading of the same in the twisting department is herewith avoided. The carrier is then - possibly on an autonomous guided vehicle - transported to a threading area.

[0058] In the threading area an operator threads the filaments through the wire path of the carrier, towards and through the cabling die. The wires are there connected together by means of a knot, swaging, soldering, welding or the like. This threading can be done in an air conditioned environment, with plenty of space to reach all spools as the operator can walk around the carrier.

[0059] The threaded carrier is then brought - possibly on an automated vehicle - to the twisting area close to the twisting machine from which the previous, run empty carrier has been removed and parked in a waiting position. The threaded carrier is lifted and mounted into the twisting machine. The carrier is then locked into position. The threaded wire end is further threaded through the machine or connected to the remaining cord end.

The connection is inched through the machine and cut out once the cord is on the take up spool. The machine is started. The empty carrier from the previous load is then put on the carrier and leaves for the filament delivery area for the collection of a new load.