GB2130259A - Skeining apparatus - Google Patents

Abstract

Apparatus for forming skeins in fine copper wire during coil winding operations comprises a pair of guides (48, 49) passing wire to a coil-winder. A chain (23) driven around two sprockets (10, 11) carries a looping finger (28) to pick up the wire and form loops around a pair of needles (32, 45). One needle (32) is carried on a spinner so that when a sufficient number of loops have been formed rotation of the spinner twists the loops into a skein. Shortening of the twisting loops is accommodated by one needle (45) swinging back towards the other. Wire tension is controlled by disc tensioners (53). A tensioner may be automatically controlled (Fig. 12). One needle (45) may be mounted on a power driven biassing and ejection assembly (Fig. 6) to control skein tension and so that the skein may be released from the needles. <IMAGE>

Description

SPECIFICATION Skeining apparatus This invention relates to skeining appara tut that is to say, apparatus arranged to operate on a filament so as to form a twisted skein therein, intermediate the ends of the filament but without severing the filament.

Though the apparatus of this invention is intended for use with a metallic monofilament-i.e. wire it may in fact be used with certain multi-stranded wires, or with certain filaments made of materials other than metals.

Though it may be required to form a skein in a filament for any of a variety of reasons, most commonly it is desirable when starting or terminating the winding a coil from wire of relatively fine gauge, or when providing a tapping part-way through a coil-winding operation. Such skeining is necessary because relatively fine wire has a very low strength and a single strand of fine copper is likely to fracture when subjected to the flexing and soldering operations necessary to terminate the coil or to provide a tapping.

Conventionally, a skein has been formed manually, by an operator folding a continuous length of the wire successively to provide several strands side-by-side and then twisting the strands axially, by rolling them between the fingers. This however requires considerable manual dexterity, and even with a skilled and experienced operator wire breakages can still easily occur. Moreover, such a manual operation makes the winding of a coil labourintensive, and hence expensive.

In view of the disadvantages of forming skeins manually, there have been certain proposals for automatic skeining apparatus, and to some extent practical embodiments of these have helped to reduce the cost of coil-winding. A typical example of such an apparatus has a flying shuttle which, when a skein is to be formed, is engaged with the wire and carries the wire round two spaced pins. One pin is then rotated with respect to the other, twisting the loops formed around the pins.

The accurate guiding the shuttle has however caused considerable problems, especially when very fine wire is being skeined-such as copper monofilaments of a diameter as small as 0.025 mm (0.001in)-and rapid rates of wear and high strains can occur when the apparatus is operated relatively quickly.

Moreover, in view of the capital cost and size of the known skeiners of this type, it is usual to construct them so as to be suitable for the simultaneous skeining of two filaments running side-by-side. However, because a breakage of one filament almost always results in the second filament breaking, it is then necessary to run the skeiner even yet slower, so as to reduce the likelihood of a breakage even more. In addition, to reduce the probability of a malfunction of the shuttle, it has been necessary to provide complex and highly accurate mechanisms to ensure the wire is carried round the pins safely without breakages, but in turn this both decreases the reliability of the apparatus and increases the capital cost thereof.

This invention has as a primary object the provision of skeining apparatus which is simplified as compared with the known form of skeining apparatus described above, and which therefore has a lower capital cost and greater reliability.

Accordingly, this invention provides skeining apparatus for skeining a filament, comprising first and second skeining needles spaced apart and disposed to allow the filament to be looped therearound, the first skeining needle being mounted on a rotatable spinner the axis of rotation of which is generally co-incident with a line passing through the two needles, and an endless flexible tension member carrrying at least one filament looping element constrained to follow such a path that on driving the tension member around said path the locus of the looping element encircles the two needles with the needles intersecting the plane of the locus, at least two spaced filament guides disposed to support a filament to be skeined to lie adjacent the skeining needles, and drive means for the flexible tension member and for the spinner, whereby driving the flexible tension member causes the looping element to loop a filament extending between the filament guides around the skeining needles, whereafter stopping the flexible tension member and rotating the spinner causes the looped filament to be twisted along the length of the loops, thereby to form the skein.

Most advantageously, the skeining apparatus of this invention is employed in a coilwinding installation, the apparatus being disposed between a reel of wire to be de-reeled prior to being wound into a coil and the coilwinder itself, with the wire running through the filament guides of the apparatus throughout a coil-winding operation. Before the winding commences, the skeining apparatus should be operated to form a skein in the wire which will form the start of the coil, and the apparatus should again be operated at the end of the winding, immediately before the last few turns (or part-turn in the case of large diameter coil) are wound on the coil.Of course if the coil is to have one or more tappings, then the winding operation should be stopped after an appropriate number of turns have been wound, the skeining apparatus operated, and then the winding operation recommenced but with the thus-formed skein doubled along its length and left loose to project out of the finished coil.

In a particularly preferred form of this appa ratus, the looping element makes no contact with the filament other than when the loops are being formed around the skeining needles, the looping element being in the form of a finger attached to the flexible tension member so as to upstand from the plane of the path around which the flexible tension member is driven, whereby the locus of the finger is parallel to the plane of the flexible tension member path. Consequently, only a relatively small drag is imparted to the filament on being drawn through the skeining apparatus other than when a skein is being formed, and the likelihood of a breakage is much reduced.

If required, two fingers may be provided on the flexible tension member so as to form two loops for each complete revolution of the flexible tension member.

This preferred form of the apparatus is especially suitable for incorporation in a complete coil-winding installation, for a single looping element together with the associated flexible tension member and drive arrangement may be provided to service a plurality of separate coil-winding mechanisms, each having first and second skeining needles and two spaced filament guides. For such an installation, the looping mechanism may be moved relative to each coil-winding mechanism to service each one in turn, as appropriate. Most conveniently, all of the coil-winding mechanisms may be mounted on a carousel to be advanced through a plurality of stations on rotation thereof, one of the stations having located thereat the looping mechanism such that a skein may be formed in the filament of the coil-winding mechanism positioned for the time being at the looping station.

An alternative form of the apparatus may have the looping element formed as a filament guide carried by the flexible tension member and through which the filament passes, but for such an embodiment it is important the the looping element should always be stopped at a predetermined position in its locus when skeining is not to take place, in order that the filament does not touch the skeining needles and follows a relatively low drag path when being drawn through the apparatus for instance to wind a coil. In this embodiment, the looping element may for example comprise a ceramic bead, or hard eyelet mounted on a rigid support attached to the flexible tension member.

For precision in operation, it is preferred for the flexible tension element to be a roller chain or a toothed belt, constrained by at least two co-planar spaced sprockets to define two parallel elongate runs between the sprockets, the runs being generally parallel to a line passing through the two skeining needles.

Further supports for the chain or belt may be provided as necessary to ensure the chain or belt follows a substantially planar path, which further guides may comprise for instance sprockets, rollers or slippers, as required.

Moreover, one of the two principal sprockets may be replaced by a roller or even a fixed arcuate slipper, but of course one sprocket still must be provided in order to allow drive to be imparted to the chain or belt.

When the flexible tension member is a chain, it is preferred for the looping element (irrespective of the design thereof) to be attached to or to form (in part) one of the side plates of the chain. However, it would be possible for the looping element itself to constitute a special link of the chain, with two ends of the chain proper being joined thereto, thus to define the endless tension member.

For the arrangement where the looping element is formed as a filament guide through which the filament runs-which arrangement is suitable for servicing only a single coilwinding mechanism-it is necessary to prevent the filament becoming wound around the filament guide on driving the flexible tension member. This may be done by providing an aperture centrally of the constraint means at the end of the two runs of the chain remote from the spinner, which aperture is formed as one of the two main filament guides, the filament then passing in sequence through the filament guide aperture, the looping element filament guide and then the other filament guide.Conveniently, the constraint means defining the filament guide aperture is in the form of a fixed slipper (rather than a sprocket) having an arcuate guide surface around which the flexible tension element passes, in order to avoid complications which would arise if a sprocket had to be rotatably mounted.

The first skeining needle mounted on the rotatable spinner is preferably provided at the free end of an arm which projects from the spinner generally parallel to the axis of rotation thereof, towards the second skeining needle. The spinner conveniently is in the form of a hollow body carried in bearings allowing the free rotation thereof, the arm projecting from an end face of the body. If required, the arm may be inclined to some extent towards the spinner axis from the point at which the arm is connected to the body, but the arm should not cross said axis. For such an arrangement, the skeining needle should extend from the free end of the arm across the axis of rotation of the spinner, preferably inclined back towards the spinner body so as to assist the retention of loops of the filament thereon, but to allow free release of the formed skein on movement of the filament through the spinner body after the skein has been released from the second needle.

An alternative form of spinner construction has a tube suitably mounted in bearings so as to project towards the second skeining needle; a part of the tube wall is cut away from the free end of the tube for at least a part of the projecting portion of the tube so as to leave an arcuate wall projecting towards the second needle in which wall the first needle is mounted. Conveniently, this is achieved by appropriately positioning the needle with respect to the wall adjacent the free end thereof and then deforming the free end portion so as firmly to clamp the needle. Instead, a drilling could be provided through the wall to receive the needle, which would then be held either by being an interference fit, or by being clamped for instance by means of an appropriately-positioned grub screw.

This invention extends to such an alternative form of spinner/first needle assembly, per se.

The second skeining needle, remote from the spinner, should be fixed against rotation about an axis parallel to or coincident with a line passing through the two needles, but the second needle preferably is mounted to allow movement thereof towards and away from the spinner (first) needle. This allows accommodation of the shortening length of the loops of filament as twisting of those loops to form the skein takes place, which shortening would otherwise have to be absorbed either by stretching of the filament or by deformation of the needles. The second skeining needle advantageously is inclined in the opposite sense to the first needle at least prior to twisting commencing-to assist the retention of loops of filament thereon.

A particularly prefered arrangement for the second skeining needle is to have the needle projecting from a carrier which is pivotally mounted to allow the needle to swing towards and away from the spinner first needle, biassing means being provided to urge the carrier such that the free end of the needle tends to move away from the spinner needle. Such biassing means may simply comprise a spring, in which case the force exerted thereby advantageously is adjustable by preloading the spring, but a preferred embodiment of the apparatus employs a biassing means which utilises an electric motor or other electric actuator arranged to apply a torque to the carrier the magnitude of which torque depends upon the voltage impressed across the motor or actuator terminals and hence upon the power dissipated within the motor or actuator.

It would be possible to continue the twisting action performed by the spinner until such time as the skein drops off the second needle, by virtue of the shortening of the loops causing the second needle to swing towards the spinner needle until the second needle has swung to such an extent that the loops can no longer be retained thereby. However, it may be wished to terminate the twisting before the second needle has swung to that extent, so the carrier for the second needle conveniently is arranged to allow the second needle to be withdrawn into the carrier, the carrier thus pushing the loops off the second needle.

Accordingly, a preferred arrangement for a second needle assembly comprises a carrier pivotally mounted for swinging movement towards and away from the spinner needle, a needle mounted on a toothed rack slidably supported on the carrier for movement along its length between a first position in which the needle is housed within the carrier and a second position in which the needle projects from the carrier, the rack extending past the pivotal axis of the carrier and being engaged by a pinion rotatable about said axis, and an electric actuator provided on a fixed part of the apparatus and arranged to drive the pinion, the arrangement being such that torque exerted by the actuator in one sense causes the pinion to rotate to drive the rack to its second position and thereafter urges the carrier to swing about its pivotal axis in a direction which moves the projected needle away from the spinner needle, and torque exerted by the actuator in the other sense allows the carrier to swing towards the spinner needle and also withdraws the needle back into the This invention extends to a second needle assembly per se for a skeining machine including a spinner needle, wherein the second needle assembly is of the form just-described above.

In addition to the second needle being able to pivot, to accommodate the shortening of the loops of the filament as the twisting thereof takes place, it is preferred for the second needle (or its carrier, as appropriate) to be mounted for adjusting movement towards and away from the spinner (first) needle, without changing the angle of inclination of the second needle. In this way, the distance between the two needles can be pre-set, so that the length of the skein formed by the apparatus can be selected to a suitable value.

The drive means employed in the skeining apparatus of this invention preferably utilises a single electric motor, sequentially to operate the flexible tension member and the spinner.

Such a configuration is of course not possible where a single looping mechanism services a plurality of coil-winding mechanisms, but where a single motor can be employed, it is convenient for there to be two drive trains from the electric motor, one leading to the drive member for the flexible tension member and the other leading to the spinner, and there being clutch assemblies in the two drive trains, allowing independent operation of each of the flexible tension member and the spinner. Preferably, each clutch assembly is electromagnetically controlled and is provided with a detent mechanism which assures the movement of the associated tension member of a spinner is arrested at the same relative disposition each time the associated clutch disconnects the drive from the motor. Conveniently, so-called " spring-clutches" can be employed for this purpose.

It will be appreciated that as the looping element performs its locus around the two skeining needles so as to form loops therearound, filament will be drawn from a source thereof-for example, a reel-and the rate at which the filament is drawn will depend upon the part of the locus along with the looping element is moving. As a consequence of this, it is necessary for particular attention to be paid to proper tensioning of the filament if breakages are to be avoided, especially when handling relatively thin filaments such as fine copper wire used in winding coils. Conventional tensioning means may be found not to be wholly suitable, because very often the actual drag imparted on a filament by such means depends upon a variety of factors, but particularly upon the speed at which the filament passes through the tensioning means.

Accordingly, it is greatly preferred for the skeining apparatus of this invention to be provide with self-adjusting tensioning means arranged between the source of the filament and the looping element, and which provides a substantially constant tension (or drag) on a filament being drawn there-through, irrespective of the filament speed. There are known self-adjusting tensioning means, but these tend to be unsuitable for use in the apparatus of this invention when skeining very fine copper wire (perhaps down to 0.001 inch leo.025 mm diameter) owing to a too low response time to change in the filament speed, and too high inertia in the moving parts. This has necessitated designing new forms of self-adjusting tensioning means, for use with the apparatus of this invention.

Thus, according to another aspect of this invention, there is provided self-adjusting filament tensioning means, comprising adjustable tensioning means through which the filament passes, adjusting means to effect adjustment of the tensioning means, means to monitor the tension in the filament and to condition an electrical signal dependent thereon, and electronic control means acting on the conditioned electrical signal and arranged to effect operation of the adjusting means dependent thereon.

There are many possible designs for suitable adjustable tensioning means which lend themselves to automatic control. For example said means may comprise a fixed first series of aligned filament guides through which the filament passes, and a second series of guides through which the filament also passes, the guides of the second series being arranged alternately with the guides of the first series, and all the guides of the second series being arranged for movement either in unison or individually away from or towards the common axis of the first series of guides.An electric motor or other actuator may be provided for each guide of the second series, or a single electric motor or other actuator may be provided where all the guides of the second series are movable in unison, thereby to effect adjustment of one or more of the guides of the second series with respect to the first series, thus to cause the filament to follow a zig-zag path to a greater or lesser extent hence varying the drag imparted on the filament.

In order to allow monitoring of the tension in a filament, it is preferred for the monitoring means to comprise two filament guides which are generally aligned, and a third guide mounted at the end of a pivoted arm biassed to move the third guide out of alignment with the other two guides, a filament passing in sequence through the guides so that it is constrained to follow a generally V-shaped path. Then, by monitoring the angle the arm makes with respect to a reference position, the tension in the filament can be assessed, because greater tensions will tend to move the third guide nearer a position where the third guide is aligned with the other two guides.

By way of example only, two specific embodients of skeining apparatus constructed in accordance with this invention and certain modifications thereto will now be described in detail, with reference being made to the accompanying drawings, in which: Figure 1 is a diagrammatic general perspective view of a first embodiment of skeining apparatus incorporating various features of this invention; Figures 2A, 2B and 2C are side views on part of the apparatus of Fig. 1, showing three stages of a filament looping sequence; Figure 3 is a diagrammatic perspective view of a second embodiment of skeining apparatus of this invention; Figure 4 is a diagrammatic perspective view of part of the apparatus of Fig. 3, taken from one end thereof; Figures 5A to 5F inclusive are diagrammatic plan views on part of the apparatus of Fig. 3, showing six stages in a skein-forming sequence; ; Figure 6 is a detailed cut-away view of a modified second needle assembly which may replace the second needle assembly employed in either of the described two embodiments of skeining apparatus; Figure 7 shows a modification of the assembly of Fig. 6, driven by a remotely-positioned motor; Figure 8 is a view of an alternative form of spinner assembly which may replace that shown in Figs. 1 and 3; Figure 9 is a diagram showing an automatic tension compensating device for use with either of the described embodiments of skeining apparatus; Figure 10 is a detailed view of part of the device as shown in Fig. 9; Figure Ii is a detailed view of 7n alterna tive form of detector to that shown in Fig. 10; Figure 12 is a part-schematic diagram of an alternative form of automatic tension compensating device;; Figure 13 is a partial plan view of a carousel-type coil-winding installation including a skeining station; and Figure 14 is a partial side view of the carousel-type coil-winding installation of Fig.

13.

Referring initially to Fig. 1, the apparatus there shown in intended for skeining insulated copper monofilament wire such as is used in winding various types of coils. Though the apparatus may be used with wire of relatively heavy gauges, it is in fact primarily intended for use with wire of relatively fine gauges, down to 0.025 mm (0.001 inch diameter).

The apparatus shown in Fig. 1 comprises a pair of sprockets 10 and 11 suitably mounted on a frame (not shown) such that the sprockets are spaced apart with their axes parallel and generally vertical. Sprocket 11 is allowed to idle, whereas sprocket 10 is secured to a drive shaft 1 2 which also carries a so-called spring clutch 1 3. The input to the spring clutch 1 3 is through a pulley 14, connected by means of a belt 1 5 running over idling pulleys 1 6 to a driving pulley 1 7 mounted on a shaft 18 of an electric motor 1 9. The spring clutch 1 3 can be actuated by means of an electromagnet 20 coupled to a pawl 21 so as to allow the free end of the pawl 21 to be moved into or out of engagement with a dog 22 provided on the rotatable outer case of the spring clutch 1 3. With the electromagnet deenergized, the free end of the pawl 21 engages the dog 22 to prevent rotation of the spring clutch 13, and drive cannot therefore be imparted from the pulley 1 4 to the sprocket 10; energization of the electromagnet 20 however removes the pawl 21 from its engagement with the dog 22 so as to allow drive to be imparted from the pulley 1 4 to the sprocket 10. Moreover, the interengagement of the dog 22 and the pawl 21 ensures that the sprocket 10 is always arrested at the same angular disposition.

An endless roller chain 23 extends around the two sprockets 10 and 11, the chain defining linear runs 24 and 25 between the two sprockets 10 and 11. Attached to one side-plate on the upper side of the chain 23 is a skein looping element 26, comprising a mounting block 27 and a finger 28 projecting therefrom at an acute angle to the direction of movement of the chain along run 24, as shown by an arrow A. Projecting from the lower face of the chain in the vicinity of the looping element 26 is a peg 29 which peg is able to co-operate with a slotted optical or inductive sensing element 30, to give an electrical output each time the peg 29 passes through the slot of the element 30.

A spinner assembly 31 is mounted adjacent the sprocket 10, the assembly supporting a spinner needle 32 generally over the sprocket 10. The spinner assembly comprises a body 33 rotatably mounted with its axis substantially horizontal and in the plane also containing the axes of the sprockets 10 and 11, the body 33 being connected to the casing 34 of a second spring clutch generally similar to the spring clutch 1 3 described above. Thus, the casing has a dog 35 formed thereon cooperable with a pawl 36, the pawl being operable by an electromagnet 37 to come into and out of engagement with the dog 35.The input to the second spring clutch is through a pulley 39, coupled by means of a belt 40 to a driving pulley 41 also mounted on the shaft 1 8 of the electric motor 19, but at the opposite end thereof to the pulley 1 7. The casing 34 of the second spring clutch is provided with a peg 42 co-operable with a slotted optical or inductive sensing element 43, so as to allow electronic counting of the number of turns performed by the casing 34 and hence of the body 33.

The body 33 supports an arm 44 which projects generally axially of the body 33, away from the second spring clutch. The arm is however inclined towards (but does not cross) the axis of the body 33 and the arm supports adjacent its free end the spinner needle 32, arranged both so as to cross the axis of the body 33 and to project back towards the body 33, generally as shown in Fig. 1.

Adjacent the sprocket 11, there is provided a second needle asembly including a second needle 45, projecting from below and between the runs 24 and 25 of the chain 23.

The second needle 45 is mounted on a carrier 46 pivotally attached to a plate 47, a spring being provided to bias the carrier 46 such that the second needle 45 normally is inclined upwardly and towards the sprocket 11, but so that the second needle 45 and the carrier 46 may pivot against the spring bias back towards the sprocket 1 0. The plate 47 is slidably mounted for movement between the runs 24 and 25 of the chain, but is securable at a desired position to allow setting of the spacing between the spinner needle 32 and the second needle 45.

Adjacent the sprocket 11, there is provided a first wire guide 48, in the form of a ceramic eyelet. A bore 49 is provided right through the spinner assembly 31, such that the bore 49 may serve as a second wire guide. The mouth of the bore in body 33 may be pro vided with a bell-shape, and to assist the prevention of wear a ceramic lining may be provided to that mouth.

Wire 51 to be wound into a coil and also to be skeined by the apparatus of this invention when appropriate, is drawn from a reel con tained within the casing 50 of a de-reeling device, the wire 51 leaving the casing through a central upper aperture 52. The wire then passes through three disc tensioners 53 and then through an eyelet 54 provided at the end of arm 55, before passing through the first wire guide 48 and then through the bore 49 in the spinner assembly 31. The arm 55 is mounted on the shaft of an electric motor across the terminals of which a voltage is impressed, such that the motor is in a stalled condition but exerts a bias on the arm to urge the eyelet away from the first wire guide 48.

The motor shaft is also suitably coupled to the disc tensioners 53 so as automatically to adjust the drag imparted thereby on the wire 51, depending upon the proximity of the eyelet 54 to the first wire guide 48. In this way, a substantially uniform tension (or drag) can be imparted to the wire extending between the first guide 48 and the bore 49.

The apparatus described above is used to skein a wire in the following manner. The rest position of the apparatus is shown in Figs. 1 and 2A and, when in this state, the wire 51 has a clear path between the first wire guide 48 and the bore 49; the wire may thus easily be drawn through the apparatus for a coil winding operation, with constant tension maintained by the disc tensioners 53 controlled by the arm 55. Then, at the place in the wire where a skein is to be formed, drawing of the wire through the apparatus is stopped, the motor 1 9 is caused to run and the electromagnet 20 is energised so that drive is imparted to the sprocket 10 and hence to the chain 23.This causes the skeining finger 28 to describe a locus passing around the needles 32 and 45, and as shown in Figs. 2A, 2B and 2C, the skeining finger 28 will pick up the wire as the finger runs round the sprocket 11 and, drawing more wire from the reel, will form a loop around the needles 45 and then 32. Each complete revolution of the chain causes another loop to be formed around the two needles and the number of loops thus-formed can be counted by monitoring the output of the sensing element 30, co-operating with the peg 29.Immediately after the element 30 provides an output indicative of the required number of loops, the electromagnet 20 is de-energised and the pawl 21 co-operates with the dog 22 to stop further rotation of the sprocket 10; by deenergising the electromagnet 20 in association with an output from the element 30, the movement of the looping element 26 will always be arrested at the same location.

Next, the electromagnet 37 is energised so as to allow drive to be imparted to the body 33 of the spinner assembly 31. This causes the spinner needle 32 to be rotated about the axis of the body 33, and thus the loops formed between the needle 32 and 45 are twisted along their lengths, to form the skein.

This action shortens the effective length of the loops and the shortening is accommodated by pivotal movement of the carrier 46 of the second needle assembly, against the spring bias applied thereto. The number of turns performed by the spinner body 31 is counted by monitoring the output of the sensing element 43 co-operating with the peg 42, so that the loops can be twisted a predetermined number of times. Then when the required number of twists have been formed, electric magnet 37 is de-energised, arresting rotation of the body 33 and a mechanism (not shown pivots the carrier 46 back towards the sprocket 10 against the spring bias to allow the skein to drop off the second needle 45 as the wire is drawn towards the part-formed coil; this also pulls the skein off the first needle 32.

An alternative to counting turns of the spinner body is to rotate the spinner body until the shortening of the loops pivots the carrier to such an extent that the second needle 45 is inclined towards the sprocket 10 allowing the skeined loops to slide off the needle 45. This method is not however preferred, even though it eliminates the need to provide the mechanism to pivot the carrier, because the skein tends to flail about on release from the second needle until the spinner is stopped, and this can lead to breakge of the formed skein.

Fig. 3 shows a second embodiment of skeining apparatus of this invention which apparatus is of somewhat similar form to the first embodiment described above; like parts or parts perfoming an essentially similar function are given like reference characters and will not be described again here.

In this second embodiment, the sprocket 11 is replaced by a flat guide plate 60 having at its end 61 remote from the sprocket 10 an arcuate surface around which the chain 23 may run. At the centre of curvature of this arcuate surface, there is provided an aperture having fitted therein a bell-shaped liner 62 of a hard material. The chain 23 carries a looping element in the form of an angle bracket 63 on which is mounted a ceramic ring 64, the axis of the ring being substantially parallel to the axis of the sprocket 10.

The second needle assembly is provided above the chain 23, and has a screw-threaded adjuster 65 for a spring 66 which biases the carrier 46 of the second needle 45, such that the needle is inclined downwardly and towards the aperture in the guide plate 60. The needle 45 is held by an armature 67 slidably arranged within the carrier 46 and springurged to a position in which the needle 45 projects to the fullest extent from the carrier, there being an electromagnet winding (not shown) arranged within the carrier 46 so as to allow the needle 45 to be retracted into the carrier 46 when the electromagnet winding is energised attracting the armature 67 against its spring bias. A switch 68 or other detector is provided to feed a position signal to a controller for the skeiner.

The arm 55 of the tensioning device is somewhat differently positioned as compared to the embodiment of Fig. 1, so as to allow proper co-operation with the aperture in the guide plate 60; the arm 55 is however coupled back to a tensioning device such as the disc tensioners 53 of the embodiment shown in Fig. 1, so as to allow a suitably constant tension to be imparted to a wire. being drawn through the apparatus.

In this second embodiment, the wire 51 is drawn from a reel (not shown) to pass through the tensioning device (also not shown), a guide 69, the eyelet 54 on the free end of the arm 55, the liner 62 in the plate 60, serving as a wire guide at the end of the wire path remote from the spinner assembly, the ring 64 carried by the chain 23, and then the wire passes through the bore 49 in the spinner assembly 31.

The operation of the just-described embodiment is generally the same as has been described above with reference to Figs. 1 and 2.

However, in this second embodiment, because the wire passes through the ring 64, the wire is always connected to the chain 23 in a manner suitable for forming loops around the two needles: because the wire does not have to be picked up by a skeining finger, this arrangement is slightly more suitable for looping a heavier gauge wire. As will be appreciated from a consideration of Figs. 5A to 5E, loops are formed around the two skeining needles 32 and 45 as the ring 64 performs its locus therearound, upon the chain 23 being driven.In particular, because the wire passes through the aperture in the guide plate 60, when the part of the chain carrying the ring 64 passes around the arcuate surface of the guide plate 60, the ring 64 moves around the aperture and the wire does not become entangled or otherwise twisted around the angle bracket 63, smooth operation of this apparatus can thereby be ensured.

Prior to the start of skeining the ring 64 is disposed at position B illustrated in Fig. 5A, and this gives a relatively smooth path for drawing wire through the apertures. Loops are formed by driving the chain, and after the required number of loops have been formed, the ring 64 is again stopped at point B (as shown in Fig. 5F) whereafter the body 33 of the spinner assembly 31 is rotated, to twist the loops along their length, as illustrated in Fig. 5F. Again, the loops may be twisted a predetermined number of times, whereafter the electromagnet within the carrier 46 may be energised, so as to attract the armature 47 and withdraw the needle 45 into the carrier, thus releasing the skeined loops. The switch 68 will detect the return of the carrier 46 to its initial (illustrated) position, allowing an indication to be given that the skein has been released.However the loops may instead be twisted until the carrier 46 for the second needle 45 has pivoted to such an extent that the loops drop off that needle, the return of the carrier being detected by switch 68, which then causes the rotation of the spinner body 33 to be stopped.

Fig. 6 shows an alternative form of second needle assembly, which may replace either of those illustrated in Figs. 1 and 3. A shaft 70 is rotatably mounted in the frame of the apparatus and pivotally supports a carrier 71 for the second needle 72. A toothed rack 73 is slidably mounted within the carrier 71, and is disposed so that its teeth mesh with a pinion 74 fixed to the shaft 70 within the carrier 71. The region of the carrier 75 from which the needle 72 projects is formed as a guide 75 for the needle, allowing the needle firmly to be supported and yet able to be withdrawn into the carrier upon rotation of the pinion 74 in the appropriate sense.

Also attached to the shaft 70, but outside the carrier 71, is a bevel gear 76, meshing with a pinion 77 provided on the shaft of a direct current electric motor 78. Impressing a voltage across the electric motor terminals with such a polarity that the motor exerts a torque in the direction of arrow C will rotate the bevel gear 76 until the needle 72 has projected to its fullest possible extent, and thereafter will drive the carrier 71 into engagement with a stop 79; thereafter, maintaining a voltage across the terminals of the motor when in a stalled condition will impart a bias on the carrier, to urge the needle 72 away from the sprocket 1 0. Detection of the carrier at this position is performed by switch 68, as in the embodiment of Fig. 3.After the loops have been formed around the two skeining needles, they are twisted along their length, and during this carrier 71 may pivot about the shaft 70, against the bias provided by the stalled motor 78. However, once the required number of twists have been formed in the loops, then the polarity applied to the motor 78 may be reversed, so that the motor will run firstly pivoting the carrier 71 until it strikes a second stop 80 and thereafter withdrawing the needle 72 into the carrier 71, to drop the skein from the needle 72.

Fig. 7 shows a modification of the device described above referring to Fig. 6, and like parts will be given like reference characters: these parts will not be described again here.

The bevel gear 76 is replaced by a toothed pulley 81, and is driven by a toothed belt 82 passing partially therearound and partially around a motor pulley 83 provided on the output shaft of a direct current electric driving motor 84. The belt is constrained by idler pulleys 85 and the two ends of the belt are coupled together by means of a spring 86 adapted to maintain the correct tension in the belt. An optical or inductive slotted detector 87 is co-operable with a peg 88 provided on the belt to allow detection of the 'home' position of the needle 72.

The arrangement of Fig. 7 operates in exactly the same manner as that of Fig. 6, but has the advantage that the motor 84 may be positioned at some distance from the needle assembly itself, for space in the region where the needle assembly has to be located may be somewhat restricted.

An alternative form of spinner is shown in Fig. 8, to replace that shown in Figs. 1 and 3.

The spinner is manufactured from a length of metal tube 90, adapted to be supported in bearings 91 and coupled to the spring clutch 34 (Figs. 1 or 3). The tube 90 projects beyond the bearings, towards the second needle assembly, and a portion of the projecting tube is cut away so as to leave a semi-circular wall. A needle 92 is clamped into the free end part of the wall by virtue of the wall being deformed therearound; the needle is held adequately firmly for the skein-forming operation and yet can be pulled out of the deformed tube end and replaced if necessary.

To prevent wear, the tube 90 is internally lined with a ceramic sleeve 93, and after manufacture the tube is polished to prevent insulation being stripped from the wire.

Figs. 9 and 10 illustrate an automatic tension controlling device which may replace that shown in Fig. 1, or which may be used in conjunction with the apparatus of Fig. 3. The device comprises a first series of fixed wire guides 95 aligned axially, and a second series of movable guides 96, again aligned axially and disposed alternately with the guides 95.

Each guide of the second series has an arm associated therewith by means of which the guide is connected to a spindle 97 driven by a direct current electric motor 98. A coil spring 99 is coupled to the spindle 97 such that the spring tends to align the guides 95 with the guides 96.

A second direct current electric motor 100 has an arm 101 mounted on its driving shaft 102, the arm having an eyelet 103 at its free end, through which wire 104 to be tensioned may pass after leaving the last first guide 95 but before passing through an outlet guide 105. An optical detector 106 for the position of the motor shaft 102 feeds an output to an amplifier and servo control 107, the output of which drives the motor 98.

The second electric motor 100 operates in a generally stalled condition and is provided with an input voltage which tends to move the eyelet 103 away from the outlet guide 105. The optical detector 106 has a quadrant 108 mounted on the shaft 102 eccentric with the centre of curvature of the arcuate edge 109 of the quadrant the edge 109 operating in association with a slotted optical transmitter/receiver pair 110 such that the quadrant 108 attenuates to a greater or lesser extent the radiation emitted by the transmitter to the receiver, depending upon the instantaneous position of the motor shaft 1 02. The output from the receiver is then amplified and used to control the voltage applied to the motor 98, so as to set the guides of the second series at the required position to impart an appropriate tension to the filament being drawn through the device.

By varying the voltage applied to the motor 100, the force imparted to the arm 101 can be varied, thus varying the drag which must be imparted by the two series of guides in order to allow the arm 101 to rest at a datum position. Clearly, the voltage applied to the motor 1 00 can be varied at a location remote from the tensioning device itself, allowing the tensioning device to find many other applications beside its use in the skeining apparatus described above.

Fig. 11 shows an alternative form of optical detector, to replace that shown in Figs. 8 and 9. In this arrangement, a disc 11 2 made of transparent material is affixed to the motor shaft 102, the disc having radial opaque lines formed thereon. The spacing between the radial lines is very close in the region 113, but is relatively wide in an opposed region 114. Consequently, the attenuation of the radiation emitted by the transmitter and re ceivedl by the receiver of the optical transmitter/receiver pair 110 will depend upon the instantaneous angular position of the disc 112.

Fig. 12 shows a closed loop automatic tensioning device which again may replace that shown in Fig. 1, or may be used other than in conjunction with skeining apparatus.

Wire 1 20 is drawn from a spool (not shown) through a dise tensioner 121 (though in practice a series of such tensioners would ordinarily be provided), and then through a tension detecting arrangement 122, including an inlet guide 123, an outlet guide 1 24 and an arm 1 25 with an eyelet 1 26 at its free end, the arm being mounted on a shaft 127. A spring (not shown) such as a hair spring or a torsion spring may be provided to apply a torque to the shaft 127 in the direction of arrow D.The shaft 127 is coupled to the shaft 1 28 of an electric motor 1 29 by means of an eddycurrent coupling, comprising an aluminium disc 1 30 affixed to shaft 1 27 and closely associated with a permanent magnet 1 31 affixed to the motor shaft 1 28. The edge of the disc 1 30 is given a ramp profile for cooperation with a slotted optical transmitter/receiver pair 132, such that an output can be obtained from device 1 32 indicative of the instantaneous angular position of the arm 125.

The disc tensioner 121 comprises a soft iron bobbin 135 defining an annular channelshaped coil-receiving section, in which is provided an electromagnet coil 1 36. The bobbin supports a non-magnetic spindle 137 co-axial therewith, on which is slidably mounted a pair of hard tensioner discs 1 38a and 1 38b, the lower disc 1 38a having affixed thereto a permanent magnet 1 39 magnetised so that its central region is one pole and its peripheral region is the other pole. Alternatively, the magnet 1 39 could be magnetised with one face one pole and the other face the other pole, and the electromagnet would have to be energised accordingly. The free end portion of the spindle 1 37 is screw-threaded and carries a threaded adjuster 140 associated with the upper disc 1 38b.

An electronic control unit 141 receives the output from the optical device 1 32 and also provides the drive for the coil 1 36 of the tensioner 121. An adjustable drive unit is provided for the motor 129, allowing selection of a particular rotational rate, and hence of a desired tension.

In use the required tension is set by adjusting the speed of the motor 129, so as to apply an appropriate force through the eddycurrent coupling to the arm 1 25. Dependent upon the speed at which the wire is drawn through the device, the arm takes up a particular attitude which is detected by the optical transmitter/receiver pair 1 32 and the output therefrom is fed to the control unit 141. This provides a drive to the coil 1 36 so as to repel the permanent magnet 1 39 with a force appropriate to set the required tension. It will be appreciated that when no drive is given to the coil 136, the permanent magnet 1 39 is attracted to the bobbin 135, thus releasing the tension, and the greater the drive to the coil, the greater the applied tension.

Referring now to Figs. 1 3 and 14, there is illustrated part of a coil-winding installation having a plurality of coil-winding mechanisms 1 50 mounted on a carousel 1 51 (or turntable) adapted for rotation about a vertical axis 152, either continously or in a series of steps. Each coil-winding mechaninsm 1 50 passes through a series of stations at each of which a particular operation is performed-for instance, loading of fresh bobbin, starting the winding of a coil, completing the winding of a coil, and so on. Such a carousel-type of coil-winding installation is known in the art and will not be described in greater detail here.

So far as is possible in the following description, the same reference characters will be used to describe like parts as have been used when describing parts illustrated in Figs.

1 to 12.

The carousel-type of coil-winding installation illustrated in Figs. 1 3 and 14 has been modified to allow the skeining of the wire being wound, at least at the beginning and end of each coil but also if necessary part way through the winding of the coil to allow the production of a tapped coil. A carrier 1 53 is pivotally mounted below and about the same axis 152 as the carousel turntable 151 and includes an arm 1 54 which upstands radially beyond the periphery of the turntable.

Mounted on this arm 1 54 is a looping mechanism 1 55 including a pair of sprockets (not shown) spaced vertically with their axes horizontal and parallel, a chain (also not shown) passing round the two sprockets such that its two runs extend vertically, a skein looping element 27 including a finger 28 projecting therefrom being mounted on the chain and there being an appropriate electric motor drive arrangement (not shown) for the sprockets and chain. Means (not shown) are provided to effect swinging movement of this looping mechanism about the axis 1 52 of the carousel turntable, so that the looping mechanism may remain in register with one of the coil-winding mechanisms 1 50 on the carousel for a predetermined arc of movement of the turntable.

Each coil-winding mechanism 1 50 mounted on the carousel is arranged to have a first guide 48, a spinner assembly including a spinner needle 32 spaced vertically below the first guide 48, and a wire tensioning means 1 56 provided above the first guide. For each coil-winding mechanism, wire is drawn by a conventional de-reeler from a spool 1 57 mounted centrally of the carousel turntable so as to pass through the wire tensioning means 1 56 into the first guide 48, and from there to extend vertically downwardly past a second skeining needle 45 towards the spinner assembly including the spinner needle 32.The wire passes through the spinner 1 60 itself and then is guided to the bobbin 1 58 on which the coil is to be wound, by means of conventional winding and layering equipment 159. Each time a skein is to be formed in the wire, the turntable 151 and looping mechanism 1 55 are caused to be juxtaposed whereupon the electric motor of the looping mechanisms is energised to cause the finger 28 to describe a locus around the two skeining needles 32 and 45, forming loops of the wire around those needles. If the turntable 151 is advanced during this, then so also should be the looping mechanism 155, at the same rate.When a sufficient number of loops have been formed around the needles, the motor of the looping mechanism is de-energised when the finger 28 is disposed at such a position that the wire is disengaged therefrom. Thereafter, the spinner 1 60 is rotated by an associated positioning motor 161 to form a skein from the loops in a manner such as has been described above with reference for example to Figs. 1 and 2.

It will be appreciated that in the above described carousel-type of coil-winding installation, considerable economies of equipment can be made because only one looping mechanism 1 55 need be provided and the modification of each (conventional) coil-winding assembly as ordinarily may be provided on a carousel-type coil-winder is relatively slight. Despite this, by incorporating various of the preferred features of the embodiments of skein forming apparatus as have been described above with reference to Figs. 1 to 12, it is possible reliably and quickly to form skeins for incorporation in a coil, without significantly affecting the speed of the overall coil-winding operation.

Claims (45)

1. Skeining apparatus for skeining a filament, comprising first and second skeining needles spaced apart and disposed to allow the filament to be looped therearound, the first skeining needle being mounted on a rotatable spinner the axis of rotation of which is generally co-incident with a line passing through the two needles, and an endless flexible tension member carrying at least one filament looping element constrained to follow such a path that on driving the tension member around said path the locus of the looping element encircles the two needles with the needles intersecting the plane of the locus, at least two spaced filament guides disposed to support a filament to be skeined to lie adjacent the skeining needles, and drive means for the flexible tension member and for the spinner, whereby driving the flexible tension member causes the looping element to loop a filament extending between the filament guides around the skeining needles, whereafter stopping the flexible tension member and rotating the spinner causes the looped filament to be twisted along the length of the loops, thereby to form the skein.

2. Apparatus according to claim 1, wherein the looping element is in the form of a finger attached to the flexible tension member so as to upstand from the plane of the path around which the flexible tension member is driven, whereby the locus of the finger is parallel to the plane of the flexible tension member path.

3. Apparatus according to claim 2, wherein two fingers are attached to the flexible tension member in an equi-spaced disposition, whereby two loops are formed for each complete revolution of the flexible tension member.

4. Apparatus according to claim 2 or claim 3, in combination with a coil-winding installation having a plurality of separate coilwinding mechanisms each having first and second skeining needles and two spaced filament guides, there being a single flexible tension member together with the associated looping element and drive arrangement.

5. Apparatus according to claim 4, wherein all of the coil-winding mechanisms are mounted on a carousel adapted for advacement through a plurality of stations on rotation thereof, one of the stations having located thereat the looping mechanism such that a skein may be formed in the filament of the coil-winding mechanisms positioned for the time being at the looping station.

6. Apparatus according to claim 1, wherein the looping element is formed as a filament guide carried by the flexible tension member and through which the filament passes.

7. Apparatus according to claim 6, wherein the looping element comprises an eyelet mounted on a rigid support attached to the flexible tension member.

8. Apparatus according to any of the preceding claims, wherein the flexible tension element comprises a roller chain or a toothed belt, constrained by at least one sprocket and a guide co-planar with the sprocket to define two parallel elongate runs which are generally parallel to a line passing through the two skeining needles.

9. Apparatus according to claim 8, wherein the flexible tension element guide comprises a further sprocket coplanar with and spaced from the first-mentioned guide.

1 0. Apparatus according to any of the preceding claims, and in which the flexible tension member comprises a chain, wherein the looping element is directly attached to or forms in part one of the side plates of the chain.

11. Apparatus according to claim 6 or any claim dependent thereon, wherein an aperture is provided centrally of the constraint means at the end of the two runs of the flexible tension member remote from the spinner, which aperture serves as one of the two main filament guides, whereby a filament may pass in sequence through the filament guide aperture, the looping element filament guide and then the other filament guide.

12. Apparatus according to claim 11, wherein the constraint means defining the filament guide aperture is in the form of a fixed slipper having an arcuate guide surface around which the flexible tension element passes.

1 3. Apparatus according to any of the preceding claims, wherein the first skeining needle mounted on the rotatable spinner is provided at the free end of an arm which projects from the spinner generally parallel to the axis of rotation thereof, towards the second skeining needle.

14. Apparatus according to claim 13, wherein the spinner is in the form of a hollow body carried in bearings allowing the free rotation thereof, the arm projecting from an end face of the body.

1 5. Apparatus according to claim 14, wherein the arm is inclined towards but does not cross the spinner axis from the point at which the arm is connected to the body.

1 6. Apparatus according to any of claims 1 3 to 15, wherein the skeining needle extends from the free end of the arm across the axis of rotation of the spinner, and is inclined back towards the spinner body thereby to assist the retention of loops of the filament thereon.

17. Apparatus according to any of claims 1 to 12, wherein the spinner comprises a tube suitably mounted in bearings so as to project towards the second skeining needle, a part of the tube wall being cut away from the free end of the tube for at least a part of the projecting portion of the tube so as to leave an arcuate wall projecting towards the second needle in which arcuate wall the first needle is mounted.

1 8. Apparatus according to claim 17, wherein the free end portions of the arcuate wall are deformed together to clamp the needle therebetween.

1 9. Apparatus according to claim 17, wherein a drilling is provided through the arcuate wall to receive the needle, which needle is then secured in the drilling.

20. Apparatus according to any of the preceding claims, wherein the second skeining needle remote from the spinner is fixed against rotation about an axis parallel to or coincident with a line passing through the two needles, but is mounted to allow movement thereof towards and away from the spinner (first) needle.

21. Apparatus according to claim 20, wherein the second skeining needle is inclined in the opposite sense to the first needle to assist the retention of loops of filament thereon.

22. Apparatus according to claim 20 or claim 21, wherein the second skeining needle projects from a carrier which is pivotally mounted to allow the needle to swing towards and away from the spinner first needle, biassing means being provided to urge the carrier such that the free end of the needle tends to move away from the spinner needle.

23. Apparatus according to claim 22, wherein the biassing means comprises a spring the force exerted thereby being adjustable by pre-loading the spring.

24. Apparatus according to claim 22, wherein the biassing means includes an electric actuator arranged to apply a torque to the carrier the magnitude of which torque depends upon the voltage impressed on the actuator and hence upon the power dissipated therewithin.

25. Apparatus according to claim 24, wherein the second needle is mounted on the carrier in such a manner that the second needle may be withdrawn into the carrier to permit formed loops to be pushed off the second needle by the carrier.

26. Apparatus according to claim 25, wherein there is provided a second needle assembly comprising a carrier pivotally mounted for swinging movement towards and away from the spinner needle, a needle mounted on a toothed rack slidably supported by the carrier for movement along its length between a first position in which the needle is housed within the carrier and a second position in which the needle projects from the carrier, the rack extending past the pivotal axis of the carrier and being engaged by a pinion rotatable about said axis, and an electric actuator provided on a fixed part of the apparatus and drivably connected to the pinion, the arrangement being such that torque exerted by the actuator in one sense causes the pinion to rotate to drive the rack to its second position and thereafter urges the carrier to swing about is pivotal axis in a direction which moves the projected needle away from the spinner needle, and torque exerted by the actuator in the other sense allows the carrier to swing towards the spinner needle and also withdraws the needle back into the carrier.

27. Apparatus according to any of claims 20 to 26, wherein the second needle or its carrier is mounted for adjusting movement towards and away from the spinner (first) needle, without changing the angle of inclination of the second needle.

28. Apparatus according to any of the preceding claims, wherein the drive means utilises a single electric motor, sequentially to operate the flexible tension member and the spinner.

29. Apparatus according to claim 28, wherein there are two drive trains from the electric motor, one leading to the drive member for the flexible tension member and the other leading to the spinner, and there being clutch assemblies in the two drive trains, allowing independent operation of each of the flexible tension member and the spinner.

30. Apparatus according to claim 29, wherein each clutch assembly is electromagnetically controlled and is provided with a detent mechanism which assures the movement of the associated tension member or of the associated spinner is arrested at the same relative disposition each time the respective clutch disconnects the drive from the motor.

31. Apparatus according to any of the preceding claims, wherein self-adjusting filament tensioning means are arranged between the source of the filament to be skeined and the looping element, and which provides a substantially constant tension (drag) on a filament being drawn therethrough, largely irrespective of the filament speed.

32. Apparatus according to claim 31, wherein the self-adjusting filament tensioning means comprises adjustable tensioning means through which the filament is to pass, adjusting means to effect adjustment of the tensioning means, means to monitor the tension in the filament and to condition an electrical signal dependent thereon, and electronic control means acting on the conditioned electrical signal and arranged to effect operation of the adjusting means dependent thereon.

33. Apparatus according to claim 32, wherein the adjustable tensioning means comprises a fixed first series of aligned filament guides through which the filament passes, and a second series of guides through which the filament also passes, the guides of the second series being arranged alternately with the guides of the first series and all the guides of the second series being arranged for movement either in unison or individually away from or towards the common axis of the first series of guides.

34. Apparatus according to claim 32, wherein the adjustable tensioning means comprises a pair of concentric discs between which the filament is to pass and an electric actuator arranged to urge the two discs together with a force suitable to impart the required tension to a filament passing between the discs.

35. Apparatus according to claim 34, wherein the electric actuator comprises an electro-magnetic device drivingly coupled to one of the discs mounted for axial adjustment with respect to the other disc.

36. Apparatus according to any of claims 32 to 34, wherein the monitoring means comprises two filament guides which are generally aligned and a third guide mounted at the end of a pivoted arm biased to move the third guide out of alignment with the other two guides, whereby a filament passing in sequence through the three guides is constrained to follow a generally V-shaped path, the angle the arm makes with respect to a reference position being used to assess the tension in the filament.

37. Apparatus according to claim 36, wherein an optical sensor is provided to determine the instantaneous angle of the arm with respect to a reference position and to provide an electrical signal dependent thereon.

38. A spinner assembly for a skeining machine, comprising a tube mounted in bearings for rotation about the axis thereof, the tube projecting beyond the bearings and a part of the tube wall being cut away from the free end of the tube for at least a part of the projecting portion of the tube so as to leave an arcuate wall extending parallel to the tube axis in which arcuate wall a needle is mounted so as to extend towards the tube axis and back towards the bearings.

39. A spinner assembly according to claim 38, wherein the needle is held clamped between the free end portions of the arcuate wall, which end portions deformed together so as securely to clamp the needle.

40. A spinner assembly according to claim 38, wherein a drilling is provided through the arcuate wall to receive the needle, which needles is then secured in the drilling.

41. A skeining needle assembly for a skeining machine, which needle assembly comprises a carrier pivotally mounted for swinging movement between two end stops, a needle mounted on a toothed rack slidably supported by the carrier for movement along its length between a first position in which the needle is housed within the carrier and a second position in which the needle projects from the carrier, the rack extending past the pivotal axis of the carrier and being engaged by a pinion rotatable about said axis, and an electric actuator provided on a fixed part of the apparatus and drivably connected to the pinion, the arrangement being such that torque exerted by the actuator in one sense causes the pinion to rotate to drive the rack to its second position and thereafter urges the carrier to swing about its pivotal axis to engage one end stop, and torque exerted by the actuator in the other sense allows the carrier to swing towards its other end stop and also withdraws the needle back into the carrier.

42. Skeining apparatus according to claim 1 and substantially as hereinbefore described, with reference to and as illustrated in Figs. 1 and 2 or in Figs. 3, 4 and 5 or as modified by any of Figs. 6 to 14 of the accompanying drawings.

43. A spinner assembly for a skeining machine substantially as herein before described with reference to and as illustrated in Fig. 8 of the accompanying drawings.

44. A skeining needle assembly for a skeining machine substantially as hereinbefore described with reference to and as illustrated in Fig. 6 or in Fig. 7 of the accompanying drawings.

45. A coil winding machine in combination with skeining apparatus according to any of claims 1 to 37 or claim 42.