US3884276A

US3884276A - Method and apparatus for forming paired leads having an intermediate twisted portion and untwisted end portions and for applying terminals or the like to the end portions

Info

Publication number: US3884276A
Application number: US474275A
Authority: US
Inventors: Daniel Eugene Poplaski
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1974-05-29
Filing date: 1974-05-29
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20

Abstract

A method and apparatus for forming a length of paired leads having twisted and untwisted portions, the leads initially being either twisted for their entire length or in an untwisted state, and also for cutting the untwisted portions and applying terminals or the like to the ends of a cut untwisted portion. The twister-untwister mechanism includes two spaced apart holding means which are adapted to engage spaced apart portions of a pair of leads, two spaced apart lead engaging means spaced away from each other and from the lead holding means and inwardly of the lead holding means, and means to rotate the lead engaging means in either a common direction, to form two short twisted lengths of untwisted leads between each of the holding means and engaging means, or in opposed directions, to form an untwisted length between the two engaging means.

Description

United States Patent 1191 Poplaski 1451 May 20, 1975 [75] Inventor: Daniel Eugene Poplaski, Harrisburg,

[73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: May 29, 1974 [21] Appl. No.: 474,275

Primary Examiner-Lowell A. Larson Attorney, Agent, or FirmWilliam J. Keating; J. L. Seitchik; F. W. Raring 57 ABSTRACT A method and apparatus for forming a length of paired leads having twisted and untwisted portions, the leads initially being either twisted for their entire length or in an untwisted state, and also for cutting the untwisted portions and applying terminals or the like to the ends of a cut untwisted portion. The twisteruntwister mechanism includes two spaced apart holding means which are adapted to engage spaced apart 52 US. Cl. 140/115; 29/203 DT- 140/149 lhorhohs Of a P of leads, Spaced apart lead 51 Int. Cl 152117/00 gaging means Spaced away hOm each other and from [58] Field of Search 140/115 149 1 the lead h1dh1g means and inwardly the lead hold- 29/203 DT 33 F 33 81/951. 57/1 6 ing means, and means to rotate the lead engaging 23 means in either a common direction, to form two short twisted lengths of untwisted leads between each [56] References Cited of the holding means and engaging means, or in opposed directions, to form an untwisted length between UNITED STATES PATENTS the two engaging means. 3,748,932 7/1973 Neiman et al. .1 81/9151 3,815,449 6/1974 Folkenroth et al. 8l/9.5l 22 C aims, 8 Drawing Flgures 68 7O 28 /s4 Y 1| 34 |66 g I64 90 I74 92 H8 84 ||0L\ I; i/lzo |20 144 I44 88 IE2 t 86 t :5;

PATENTEDMAY20 1975 3,884,276

SHEET 2 BF 8 PATENTEDMAYZO I975 SHEET 3 BF 8 H, MAN 0mm NNN METHOD AND APPARATUS FOR FORMING PAIRED LEADS HAVING AN INTERMEDIATE TWISTED PORTION AND UNTWISTED END PORTIONS AND FOR APPLYING TERMINALS OR THE LIKE TO THE END PORTIONS FIELD OF THE INVENTION The present invention relates generally to a method and apparatus for forming a length of paired leads having twisted and untwisted portions and also for applying terminals or the like to severed end portions of the untwisted length.

BACKGROUND OF THE INVENTION Twisted paired leads are widely used in the electrical industry for several reasons, for example, if two leads in a circuit are twisted together, lead to lead inductance effects are minimized and cross-talk between adjacent pairs of leads is reduced or eliminated. In addition, if two associated leads are twisted together in a harness, rather than separately incorporated into the harness, a more compact and neater harness is achieved and the tracing and identification of the leads may be simplified.

In the past it has been customary when forming a length of twisted paired leads having terminals affixed to the ends of the leads to initially measure the overall length of the leads from a source of supply of twisted paired leads, to manually untwist the ends of the leads, to strip the ends of the leads, and then to place the stripped ends of the leads in a terminal applicator for the application of terminals thereto. As can be appreciated this process requires much hand labor.

This procedure has been simplified somewhat by the development of the apparatus shown in US. Pat. No. 3,795,159 issued Mar. 5, 1974 to Steiner, et al., this patented apparatus untwisting the ends of twisted paired leads and also stripping the ends of leads. However, even with this patented apparatus it is still necessary to pre-measure the various lengths and to manually place them in the apparatus shown in the foregoing patent as well as in a terminal applicator.

Other machines have been developed for applying terminals to a pair of wires which are not twisted together wherein terminals are initially applied to the leading ends of-stripped leads which extend away from a source of supply, the leading ends with the terminals affixed then being fed past a cutting and stripping zone, the machine then cutting the leads which have been fed past the cutting and stripping zone and stripping the ends of the leading and trailing ends of the just severed leads, and then transferring the trailing ends to additional terminal applicators for the application of terminals thereto. One commercial variation of this machine is manufactured by the Assignee of the present application and is known in the trade as the AMPOMATOR IV-C and is based upon the machine shown in US. Pat. No. 3,019,679 issued Feb. 6, 1962 to Schwalm, et al. While the AMPOMATOR IV-C has been capable of applying terminals to the leading and trailing ends of paired wires which are parallel to each other, it has been unable in the past to handle twisted wires as the machine is unable to strip twisted leads. is unable to apply terminals to twisted leads, and has lacked the capability to either untwist the ends of twisted paired leads prior to stripping or to twist portions of untwisted leads.

OBJECTS AND SUMMARY OF THE INVENTION It is a principle object of the present invention to provide an untwister-twister apparatus for use with machines which apply terminals to the leading and trailing ends of a pair of leads whereby such a machine may manufacture pairs of leads having terminals applied to the ends of the leads, theintermediate portion of the leads being twisted.

It is a further object of the present invention to provide a method and apparatus for untwisting an intermediate portion of paired twisted leads.

It is another object of the present invention to provide a method and apparatus for twisting two spaced apart portions of a pair of leads which are initially in an untwisted state.

The foregoing objects and other objects and advantages of the present invention are accomplished by providing an apparatus having first and second spaced apart lead holding means, first and second spaced apart rotatable lead engaging means located between lead holding means and spaced away from each other and the lead holding means, and means operable to rotate the first and second spaced apart rotatable lead engaging means in either a common direction or in opposed directions. The parts are so arranged and constructed that when the rotatable lead engaging means are rotated in a common direction a pair of leads, which are initially in an untwisted state, will be twisted between each of the lead holding means and the rotatable lead engaging means while leaving that portion of the leads between the two rotatable lead engaging means in an untwisted state. The parts are also so constructed and arranged that when the rotatable lead engaging means are rotated in opposed directions they will untwist previously twisted paired leads between the rotatable lead engaging means.

The foregoing apparatus may be incorporated into a machine capable of terminating the leading and trailing ends of a pair of leads, which machine may be of the type shown in US. Pat. No. 3,019,679.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an apparatus adapted to apply terminals to the leading and trailing ends of paired twisted leads.

FIG. 2 is a perspecitve view of a portion of the apparatus shown in FIG. 1, the portion shown being capable of twisting or untwisting paired leads.

FIG. 3 is a side view of the apparatus shown in FIG. 2 with parts being broken away.

FIG. 4 is a plan view of the apparatus shown in FIG. 2 with parts being broken away.

FIG. 5 is a section taken generally along the lines 5-5 in FIG. 4, the parts being shown in an inoperative position.

FIG. 6 is a view similar to FIG. 5, the parts being shown in an operative or twisting position.

FIGS. 7 and 8 are sections taken along the lines 77 and 8-8 in FIGS. 5 and 6, respectively.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring first to FIG. 1, a lead making machine is illustrated, the lead making machine being able to apply terminals 10 to the leading and trailing

ends

12, 14, respectively, of a pair of leads 15, the finished pair of leads having an intermediate portion which is twisted together, the twisted portion of the finished leads being indicated at 17. The machine includes lead cutting means 16 disposed at a cutting zone, two spaced apart sets of applying means or terminal applicators 18 located at applicator stations, transfer means 20 disposed to either side of the lead cutting means 16, feeding means 22, lead measuring means 24, and a source of supply 26. Various of the components are mounted on a bench 28 which also supports spools 30 which carry interconnected terminals 32. The terminals which are to be applied by the applicator means 18 are received from the spools 30 in a manner well known in the art.

When applying terminals to paired leads (which in prior art machines may come from either separate single wire spools 26 or from a single spool carrying paired parallel leads) the lead measuring means will measure out a length of paired leads and the cutting means 16 will cut and strip a pair of leads which extend through the cutting zone to form cut trailing and leading ends which are initially in register with each other. The transfer means 20 will then be swung from their full line position in FIG. 1 to their dotted line position to place the cut leading and trailing ends in register with terminal applicators or the like at which time terminals will be applied to the cut trailing and leading ends. The pair of leads which have terminals applied to the trailing ends have had terminals previously applied to their leading ends and the completed pair of leads is then discharged onto a discharge chute 34. The transfer means are then swung back to their full line position where they are in registry with the cutting means and the previously measured length of paired leads is then fed past the cutting means. In this connection it should be noted that the leading ends have already had the terminals applied thereto. After this point the cycle of operation is again repeated with an additional length of leads being measured by the lead measuring means 24, the cutting means cutting and stripping new trailing and leading ends, and terminals being applied to the new trailing and leading ends.

The foregoing structure is generally well known in the art but up until this time has been incapable of applying terminals to leads which are twisted together. This is because the cutting means 16 and the terminal applicators 18 are incapable of properly stripping twisted leads and applying terminals thereto as it is necessary that there be some separation and orientation of the leads prior to stripping and the application of terminals.

In accordance with the principles of the present invention novel twister-untwister means are provided which are capable of either untwisting an intermediate portion of twisted paired leads or, in an alternative mode of operation, twisting two spaced apart portions of leads which are initially untwisted. The twisting or untwisting means is indicated generally at 36 and may be disposed between the lead measuring means 24 and the lead feeding means 22.

The lead twisting-untwisting means 36 is mounted on a support bar 38, which extends from the cutting means 16 to the lead measuring means 24, and the twisteruntwister can be positioned at any desirable location between the cutting means and the measuring means, and is preferably located between the feeding means 22 and the measuring means 24. To this end, the twisting or untwisting means 36 is provided with a mounting structure indicated generally at 40 (FIG. 2), the mounting structure including first and second upwardly extending L-

shaped frame members

42, 44 which are each interconnected at their upper end with a box frame structure 46 which is slidable along the support bar 38. A knurled screw 48 is mounted with a threaded aperture on one side of the box frame structure 46 and is adapted to secure the box frame structure to the support bar 38 in various desired locations.

In addition to the mounting structure 40, the twisting-untwisting means 36 further includes two substantially identical first and second subassemblies, indicated generally at 50, 52, respectively, each of which carries various operative components which are employed to twist or untwist paired leads. Each subassembly includes a main frame member 54, and the two main frame members 54 of the

subassemblies

50, 52 are secured to upper and

lower mounting blocks

56, 58, respectively, by means of threaded fasteners 60. By varying the width of the

mounting block

56, 58, or by employing shims (not shown) the spacing between the two

assemblies

50, 52 may be varied. The lower end of each of the L-

shaped frame members

42, 44 is in turn secured to the upper mounting block 56 means of fasteners 62.

Mounted on the first and

second subassemblies

50, 52 are first and second lead holding means, indicated generally at 64, 66, respectively, first and second rotatable lead engaging means, indicated generally at 68, 70, respectively, (FIG. 4) and first and second rotating means, indicated generally at 72, 74, respectively. As each of the subassemblies is substantially identical, common reference numerals will be employed in describing the various components of each of the subassemblies.

With particular reference to FIGS. 2, 4, 7, and 8, each of the lead holding means 64, 66 includes an elongated block 76 which is secured to the outer side of the main frame member 54 by an L-shaped mounting bracket 77. Each elongated block. has an aperture 78 which extends from the outer side 80 to the inner side 82, the inner side of the first and second lead holding means facing each other. The pair of leads 15 which are to be either twisted or untwisted extend through the apertures 78. The elongated block 76 is also provided with a bore 84 transverse to the aperture 78, the bore having a shoulder portion 86. A pin 88 is carried by a cylindrical member 90 within the bore 84, the cylindrical member 90 normally being spring biased away from the aperture 78 by a compression spring 92. A threaded member 94 is carried by a threaded aperture within the cylindrical member 90 and extends outwardly of the elongated block. A support plate 98 has one end secured to the elongated block 76 by fasteners 100. An air cylinder 102 is secured to the other end of plate 98 by fasteners 103. A rod 104 extends outwardly of the air cylinder and carries a block 106 which is adapted to contact the threaded member 94 when the rod is extended to bias the pin 88 into clamping engagement with the pair of leads 15 received within the aperture 78 of the elongated block 76. When the cylinder is retracted, the spring 92 will bias the pin 88 out of its clamping engagement with the pair of leads in the aperture 78. Suitable air lines (not shown) are connected to fittings 108 on the cylinders 102, the air lines being in turn connected in turn with valve means for causing the holding means to be operated in a suitable manner.

The first and second rotatable

lead engaging means

68, 70 are best shown in FIGS. 5 through 8 and include a rotatable support indicated generally at 110. The rotatable support has an intermediate cylindrical portion 112 which is supported by a pair of ball bearings 114 for rotation within the main frame member 54 and a cylindrical sleeve member 116, which is welded to the main frame member. The cylindrical sleeve member 116 and the main frame member have suitable apertures for the reception of the ball bearings 114 and the rotatable member 110. The rotatable support member 110 is held from relative axial movement with respect to the ball bearings by a retaining ring 118 which engages the inner race of one of the ball bearings and a shoulder portion 120 which engages the inner race of the other ball bearing. Each of the rotatable supports 110 also includes a cylindrical extension 122 which extends away from the outer side of the main frame member 54, the cylindrical extension 122 being provided with a gear 124 at its outer end. The inner end of each end of the rotatable supports 110 is an enlarged disc shaped portion 126 having a generally circular periphery 128. The rotatable support 110 is provided with an aperture 130 which extends through the intermediate cylindrical portion 112, the cylindrical extension 122, and the disc shaped portion 112, the aperture 130 being concentric with the axis of rotation of the rotatable support 110, and the aperture 130 being adapted to receive a pair of leads 15.

A pair of lead clamping means, indicated generally at 132, are mounted on the inner face of each of the disc shaped portions 126 on opposite sides of the aperture 130. Each of these pairs of lead clamping means 132 includes a lead clamp assembly, indicated generally at 134, and a slide assembly, indicated generally at 136. Each of the lead clamp assemblies includes a clamp retainer 138 which is pivotally secured to the face of the disc shaped portion 126 by a pivot pin 140, the pivot pin 140 being secured to the disc shaped portion 126, and a retaining ring 142 engaging a groove in the outer end of the pin to maintain the clamp retainer 138 in place. Each of the clamp retainers 138 is provided with a cut-out portion in which is mounted a hardened wire clamp 144 which is held in place by a threaded fastener 146. Each of the clamp retainers is also provided with a recessed area 148 (FIG. 5) through which extend pivot means in the form ofa pin 150, one end of the pin 150 being force fitted or otherwise secured to the clamp retainer adjacent the recessed area 148.

Each of the slide assemblies 136 includes a slide member 152 having an elongated intermediate portion 154, a first outer end portion 156 extending away from one end of the intermediate portion 154 at right angles thereto, and a second outer end portion 158 extending away from the other end of the intermediate portion 154 at right angles thereto and in an opposed direction to the first outer end portion 156, the second outer end portion 158 having a thickened extension 160. The end of the first outer end portion 156 remote from the intermediate portion 154 is provided with an elongated aperture 162 (FIG. 5), the end of the portion 156 which is provided with the aperture 162 being disposed within the recessed area 148 of the clamp retainer 138, and the elongated aperture 162 receiving the pin 150. Thus, the pin 150 and elongated aperture 162 serve as means to interconnect the slide assembly with the lead clamp assembly. The thickened extension 160 is provided with a threaded aperture which receives a shouldered screw 164, the screw being employed to secure a roller 166 to the extension, the periphery of the roller 166 extending beyond the outer limit of the second outer end portion 158. The thickened extension is provided with an extension portion 168, the extension portion 168 being provided with a recess which receives one end 170 of a compression spring 172. A cover member 174 is secured to the disc shaped portion 128 by threaded fasteners 176 and serves to maintain the slides in their proper assembled relationship while permitting them to reciprocate in the direction indicated by the arrow 178 (FIG 5). It should be noted at this point that the inner surface of the disc shaped portion 126 is provided with channels within which each of the slide assemblies may slide. While this is the preferred structure it should be observed that alternative channels could be provided in the cover member 174. The other end 180 of the spring 172 is received within a recessed portion 182 of the cover 174. Thus, the spring will normally bias the slide assembly 152 away from the aperture 130 to dispose the periphery of the roller 166 beyond the circular periphery 128 of the disc shaped portion 126.

As will become more apparent below, if the slides are caused to move inwardly towards the aperture 130, this will cause the lead clamp assemblies 134 to pivot about the pivot pin 140 in the direction indicated by the arrow 184 from the position shown in FIG. 5 to the position shown in FIG. 6, the hardened wire clamps 144 firmly engaging a pair of leads after they have been pivoted to their operating position shown in FIG. 6.

Referring now principally to FIGS. 2 and 3, the first and second rotating means 72, 74 each includes a double acting cylinder assembly 186, which may be either hydraulic or pneumatic, the cylinder assembly 186 being rigidly mounted on the lower end portion of the main frame member 54. Each of the cylinder assemblies 186 is provided with inlet and outlet portions indicated by fittings 188 which may in turn be selectively interconnected with a high pressure line 190 and an exhaust line 192. The manner in which the cylinder assemblies 186 are interconnected with the high and

lower pressure lines

190 and 192 will be more fully brought out below in the discussion of the operation of this apparatus.

Reciprocal rod means 194 extend outwardly of each of the cylinder assemblies 186 and each of the rod means 194 is interconnected with a rack 196 by a coupling 198. Each of the racks 196 is provided with a slide portion which is received within a slide block 200 which in turn in rigidly secured. to the main frame mem ber by fasteners 202, the slide block ensuring linear movement of the rack 196. A jack shaft 204 is rotatably mounted on the main frame member 54 and extends outwardly therefrom, the jack shaft carrying first and

second gears

206, 208, respectively, which rotate with the jack shaft 204, the first gear 206 being of a relatively large diameter and engaging the gear 124 carried by the rotatable support 110. The second gear 208 is engaged by the teeth 210 of the rack 196. As the reciprocal rod means is extended or retracted the teeth 210 on the rack 196 will engage the teeth on the second gear 208 causing the second gear and the first gear to rotate, the first gear then causing the rotatable support to rotate.

It is necessary for the lead clamping means to be moved from their inoperative posititon shown in FIG. to their operative position shown in FIG. 6 before the rotatable support 110 is rotated and to this end a pair of shoes 212 is provided. Each of the shoes may be re ciprocated in the direction indicated by the arrows 214 in FIG. 5. As can best be seen from FIG. 2 the pair of shoes 212 is mounted between the main frame members 54. The shoes 212 are secured to slide blocks 216 which are mounted for reciprocal movement on a mounting frame member 218, the blocks 216 being in turn interconnected by a coupling 220 with a rod 222 which extends outwardly from double acting cylinder assembly indicated generally at 224, the cylinder assembly 224 also being mounted on the mounting frame member 218. The mounting frame member 218 is in turn secured to the upper mounting block 56 by mounting

members

226, 228. Each of the cylinders 224 are provided with fittings 230 which are selectively interconnectable with high and low pressure lines. Each of the shoes 212 is provided with a semi-cylindrical concave surface 232 (FIG. 5). Thus, when the fittings 230 remote from the rod end of the cylinder 224 are interconnected with the high pressure lines the rod 222 will be extended forcing the semi-cylindrical concave surfaces into contact with the outer peripheral surface of the roller 166 which will then cause the slide 152 to move toward the aperture 130, in turn causing the clamp retainers 138 to pivot from their open position shown in FIG. 5 to their closed position shown in FIG.

OPERATION The foregoing apparatus may be operated in basically two differing modes. Thus, each of the first and second rotatable

lead engaging means

68, 70 may be rotated in opposed directions opposite to the twist of twisted paired leads to untwist a section of the leads disposed between the two rotatable lead engaging means, or alternatively they may both be rotated in the same direction to concurrently twist two sections of paired untwisted leads between the lead holding means and the lead engaging means while leaving that portion of the leads between the two rotatable lead engaging means in an untwisted form.

When it is desired to work with twisted paired leads the twisted paired leads are initially fed from the supply spool 26 through the lead measuring means 24 and then through the aperture 78 in the first lead holding means 64, the aperture 130 in the first rotatable lead engaging means 68, the aperture 130 in the second rotatable lead engaging means 70 and the aperture 78 in the second lead holding means 66, the leading end of the paired twisted wires being fed past the feeding means 22 and to the cutting means 16. The initial position of the various parts of the twisting and untwisting apparatus 36 are best shown in FIGS. 5 and 7. Thus, in the initial position the pins 88 are biased away from the apertures 78 by the springs 92 and the inner semicylindrical concave surface 232 of the shoes 212 are spaced away from the rollers 166, thereby permitting the springs 172 to bias the lead clamping means 144 to their inoperative position shown in FIG. 5.

In order to untwist a pair of twisted leads it is necessary to bias the pins 88 into contact with the twisted pair of leads and to this end the cylinders 102 are actuated to force the pins toward the side of the apertures 78 remote from the pins until the paired twisted leads are firmly held. Also, the cylinders 224 are actuated to move the shoes 212 towards each other to force the rollers inwardly towards the aperture 130 to move the lead holding means to their operative positions shown in FIG. 6. When the shoes 212 are in their inner position the inner surfaces 232 will define a cylindrical inner surface area and a shoulder portion 234 on one of the shoes 212 will overlie an end portion 236 of the other shoe to facilitate the maintenance of the cylindrical surface during the rotation of the rotatable support 110. Thus, it should be noted that during the rotation of the rotatable support 110, centrifical force is imparted upon the inner cylindrical surfaces 232 by the rollers 166, and the shoulders 234 which engage the end portion 236 of the other shoe assist the shoes 212 from spreading apart against the centrifical force of the rotating parts. The operative position is illustrated in FIGS. 6 and 8. The first and second rotating means 72, 74 are now simultaneously actuated by extending each of the rods 194 which will in turn cause the rotatable support 110 to rotate due to the interaction of the

gearing

210, 208, 206, and 124. The stroke of the cylinders 186 is precisely controlled relative to the spacing between the two rotatable

lead engaging means

68 and 70 and the twist of the paired twisted leads to cause that portion of the leads between the two lead engaging means to become untwisted in a manner illustrated in FIG. 8. While this portion is being untwisted an additional twist will be imparted to the paired twisted wires between each of the rotatable lead holding means and the lead holding means 64, 66.

The operation of the cylinder 186 is in part controlled by

valve

238, 240 which are in turn selectively positioned through the operation of suitable control means 242, 244. The two

valves

238, 240 are shown schematically in FIG. 2 in that position where they are so positioned to cause the rods 194 to be extended. After the rods 194 have been extended to their desired position, the valve 238 is reversed through the operation of the control means 242 to cause the rods to retract before another untwisting operation. However, before the reversing of the valve 238 can take place, the shoes are moved out of engagement with each other and pins 88 are moved to their retracted position so that the leads will not be operatively engaged during the retraction of the rods.

Upon the completion of the foregoing operation, a measured length of leads is then fed by the feeding means 22 to present a new section of twisted paired leads within the twisting and untwisting apparatus 36 and the operation is again repeated, the new section which is fed being equal to the final desired length of the terminated pair of leads.

In some situations it is not practical with the foregoing operation to prepare suitable short lengths of twisted paired leads from paired leads which are initially twisted together as it has been found desirable to have the minimum length of terminated twisted paired leads formed from twisted leads approximately equal in length to the distance between the two lead holding means 64, 66. Therefore, when it is desirable to form even shorter lengths the foregoing apparatus can be operated in a differing mode to prepare twisted lengths of wire from untwisted paired leads where the twisted lengths are formed between the rotatable lead holding means 68, and the corresponding lead holding means 64, 66. In this mode of operation the cylinders 186 will be operated in opposed directions relative to each other which will in turn cause the lead holding means 68, 70 to rotate in a common direction relative to each other. To provide for such reverse operation of the cylinders 186, the valve 240 is shifted from the position shown in FIG. 2 to its alternate position. During this mode of operation, with the exception of the change in the disposition of the valve 240 and the fact that initially unpaired leads are being operated on, all the other operations will be substantially the same. Upon the completion of the operation twisted leads will have been formed between the lead holding means 64 and the rotatable lead engaging means 68 and another twisted pair of leads will be formed between the lead holding means 66 and the rotatable lead engaging means 70. However, that portion of the leads which remain between the two rotatable

lead engaging means

68, 70 will remain untwisted. Upon the completion of the twisting operation, the feeding means 22 will now be actuated to feed a desired increment of leads, the various termination steps will take place, the feeding means will then again be actuated to feed another measured increment of leads, and additional termination steps will take place before the twisting means is again caused to be operated. Thus, stated another way, there will be two sets of feeding and terminating operations when twisting untwisted leads for each cycle of operation of the twisted means, while in the previous operation of untwisting there will be only a single feeding and terminating operation for each operation of the untwisting means. V

While the preferred structure in which the principles of the present invention have been incorporated is shown and described above, it is to be understood that the invention is not to be limited to the particular details shown and described above, but that, in fact, widely differing means may be employed in the practice of the broader aspects of the invention.

What is claimed is:

l. A method of forming a terminated pair of twisted leads from a source of twisted leads comprising the steps of:

providing a source of supply of twisted pairs of leads having a free end;

holding two spaced apart portions of the twisted paired leads between the free end and the source of supply and engaging two intermediate portions between the two held portions;

rotating the two intermediate portions in opposed directions to untwist the leads between the two intermediate portions;

feeding the untwisted leads to a cutting zone;

cutting .the untwisted leads at the cutting zone to form cut trailing and leading ends, the leading ends still being interconnected with the source of sup- P y;

transferring the leading ends to an applicator station for the application of terminals thereto and then repositioning the leading ends in alignment with the cutting zone;

holding two spaced apart portions of the twisted paired leads between the untwisted portion and the source of supply and engaging two intermediate portions between the two held portions;

rotating the two intermediate portions in opposed directions to form an additional untwisted portion;

feeding an additional untwisted portion into the cutting zone while advancing the untwisted portion which has the terminals affixed to the leading ends through and past the cutting zone;

severing the additional untwisted portion; and

applying terminals or the like to the trailing ends of the severed additional untwisted portion.

2. A method of forming a pair of twisted leads from two untwisted leads and affixing terminals to the leading and trailing ends of the pair of twisted leads comprising the steps of:

providing a source of supply for two leads in an untwisted state; twisting two short spaced apart lengths of the leads between their leading ends and their source of supply together while leaving an intermediate portion between the two twisted lengths untwisted;

feeding a measured amount of twisted-untwisted wire to a cutting zone to present an untwisted portion to the cutting zone;

cutting an untwisted portion at the cutting zone to form cut trailing and leading ends, the leading ends still being connected to the source of supply; transferring the leading ends to terminal applicators; applying terminals to the leading ends; repositioning the leading ends in line with the cutting zone; advancing another measured amountof the twisteduntwisted portion past the cutting zone until the next untwisted portion is disposed within the cutting zone; cutting the untwisted portion at the cutting zone to form new cut and trailing ends, the new leading ends still being connected to the source of supply;

transferring the new leading ends to terminal applicators;

applying terminals to the new leading ends;

transferring the new trailing ends to additional termi' nal applicators; and

applying terminals to the new trailing ends.

3. The method set forth in claim 2 in which the step of twisting two short spaced apart lengths of the leads between the leading ends and their source of supply to gether while leaving an intermediate portion between two twisted lengths untwisted. comprises the following steps:

engaging two spaced apart portions of untwisted wire and holding said portions from rotation;

engaging two other spaced apart portions, said other spaced apart portions being disposed inwardly of those portions which are being held from rotation and spaced away from each other and the portions which are being held; and

rotating said other portions in a common direction to twist the wire between the held portion and the other portion while leaving the leads between the two other portions in an untwisted state.

4. A method of forming twisted-untwisted paired leads from a source of supply of twisted leads so that subsequent automatic machine operations may be performed upon the untwisted portion of the twisteduntwisted pair of leads, said. method comprising the steps of:

providing a source of supply of twisted paired leads having a free end;

holding two spaced apart portions of the twisted paired leads from rotation between the free end and the source of supply;

engaging two intermediate portions between the two held portions; rotating the two intermediate portions in opposed directions relative to each other to untwist the twisted paired leads between the two intermediate portions to form an initial untwisted portion;

holding two additional spaced apart portions of the twisted pair of leads between the untwisted portion and the source of supply;

engaging two intermediate portions between the two held portions; and rotating the two intermediate portions in opposed directions to untwist the leads between the two intermediate portions to form paired leads having twisted-untwisted portions suitable for subsequent automatic machine operation on the untwisted portions such as the application of terminals to severed untwisted portions. 5. In an apparatus adapted to apply terminals or the like to both ends of a pair of leads which are initially twisted about each other at a source of supply, said apparatus including:

lead cutting means operable to cut a pair of leads to form an additional pair of cut leads whose trailing ends are initially in register with the leading ends of the pair of leads which still extend away from the source of supply which is located to one side of the cutting means; applying means disposed to either side of said cutting means and operable to apply terminals or the like to one or more of the cut trailing and leading ends;

transfer means operable to transfer the cut trailing and leading ends from a first position adjacent said cutting means to said applying means for the application of terminals or the like thereto, and to further transfer the cut leading ends back to their first position, and

feeding means disposed to the same side of the cutting means so the source of supply and operable to feed the pair of leads which are still connected to the source of supply past the cutting means after terminals or the like have been applied to one or more of the leading ends and after they have been transferred back to their first position;

the combination therewith of untwisting means operable to untwist a pair of twisted leads to expose individual leads for cutting and the application of terminals or the like thereto, said untwisting means being disposed between the lead cutting means and the source of supply.

6. The apparatus set forth in claim in which said untwisting means includes first and second spaced apart lead holding means, first and second spaced apart rotatable lead engaging means located between the lead holding means and spaced away from each other and the lead holding means, and first and second rotating means operable to rotate said first and second rotatable lead engaging means, respectively, in opposed directions to untwist the pair of twisted leads between the spaced apart rotatable lead engaging means.

7. In an apparatus adapted to apply terminals or the like to both ends of a pair of leads which are initially not twisted about each other at a source of supply, said apparatus including:

lead cutting means operable to cut a pair of leads to form an additional pair of cut leads whose trailing ends are initially in register with the leading ends of the pair of leads which still extend away from the source of supply which is located to one side of the cutting-,means; applying means disposed to either side of said cutting means and operable to apply terminals or the like to one or more of the cut trailing and leading ends;

transfer means operable to transfer the cut trailing and leading ends from a first position adjacent said cutting means to said applying means for the application of terminals or the like thereto, and to further transfer the cut leading ends back to their first position; and

feeding means disposed to the same side of the cutting means as the source of supply and operable to feed the pair of leads which are still connected to the source of supply past the cutting means after terminals or the like have been applied to one or more of the leading ends and after they have been transferred back to their first position;

the combination therewith of twisting means operable to twist two short spaced apart lengths of a pair of untwisted leads, said twisting means being disposed between the cutting means and the source of supply, said twisting means forming a pair of leads having twisted and untwisted portions, said feed means feeding untwisted portions to said cutting means and said lead cutting means being operable to sever an untwisted portion.

8. The apparatus set forth in claim 7 in which said twisting means includes first and second spaced apart lead holding means, first and second spaced apart rotatable lead engaging means located between the lead holding means and spaced away from each other and the lead holding means, and first and second rotating means operable to rotate said first and second rotatable lead engaging means, respectively, in a common direction to form a first twisted length between the first lead holding means and the first rotatable lead engaging means and to form a second twisted length between the second lead holding means and the second rotatable lead engaging means, the portion of the leads between the first and second spaced apart rotatable lead engaging means remaining in an untwisted form.

9. An apparatus suitable for either untwisting an intermediate portion of a pair of twisted leads or for twisting two intermediate portions of a pair of untwisted leads, said apparatus comprising:

first and second spaced apart lead holding means;

first and second spaced apart rotatable lead engaging means located between the lead holding means and spaced away from each other and the lead holding means; and

first and second rotating means operable to rotate said first and second rotatable lead engaging means, respectively, said rotating means being selectively operable to rotate said rotatable lead engaging means in either a common direction or in opposed directions the parts being so arranged and constructed that when untwisting leads the first and second rotatable lead engaging means will rotate in opposed directions relative to each other and opposite to the twist of the leads to untwist the portion of the twisted leads between the rotatable lead engaging means and also so constructed and arranged that when twisting untwisted leads, the rotatable lead engaging means will rotate in a common direction relative to each other to form two twisted lengths between the rotatable lead engaging means and the holding means while leaving that portion of the leads between first and second rotatable lead engaging means in an untwisted state.

10. The apparatus set forth in claim 9 wherein each of said first and second rotating means includes a double acting cylinder assembly having reciprocal rod means, a rack interconnected with said rod means, gearing interconnecting said rack with said rotatable lead engaging means, and means interconnecting said cylinder assembly with high and low pressure lines, said interconnecting means including reversing means whereby one cylinder assembly may be operated in either the same manner as the other cylinder or in a reverse manner.

11. An apparatus suitable for either untwisting an intermediate portion of a pair of twisted leads or for twisting two intermediate portions of a pair of untwisted leads, said apparatus comprising:

mounting structure;

first and second spaced apart sub-assemblies carried by said mounting structure. each of said sub assemblies including a frame;

lead holding means mounted on each of said frames and adapted to engage a plurality of leads;

rotatable lead engaging means mounted on each of said frames in spaced apart relationship relative to said lead holding means; and

means mounted on each of said frames operative to rotate said rotatable lead engaging means selectively in either direction about its axis.

12. Apparatus for forming a length of twisteduntwisted leads from a plurality of leads comprising;

frame means; lead holding means mounted on said frame means and adapted to engage a plurality of leads; rotatable lead engaging means mounted on said frame means in spaced apart relationship relative to said lead holding means, said rotatable lead engaging means including a rotatable support rotatable about an axis, said support having an aperture extending therethrough concentric with its axis for the reception of a plurality of leads, and

a pair of lead clamping means mounted on said rotatable support on opposite sides of said aperture and movable between open inoperative and closed operative positions;

a pair of shoes mounted on said frame means on opposite sides of said rotatable support for movement towards and away from said rotatable support between operative and inoperative positions, respectively, each of said pair of shoes having a semicylindrical concave surface engagable with said lead clamping means when said pair of shoes are in their operative position to cause said lead clamping means to be disposed in their operative position;

means mounted on said frame means operative to rotate said rotatable support; and

means mounted on said frame means operative to move said shoes between their operative and inoperative positions.

13. The apparatus set forth in claim 12 in which each of said pair of lead clamping means includes a lead clamp assembly pivotally mounted on said rotatable support.

14. The apparatus set forth in claim 13 wherein each of said pair of lead clamping means further includes a slide assembly movable toward and away from the aperture in said rotatable support between operative and inoperative positions. respectively; and means interconnecting each slide assembly with a lead clamp assembly.

15. The apparatus set forth in claim 14 wherein said means interconnecting includes pin means mounted on one of said slide assembly and lead clamp assembly and an elongated aperture mounted on the other of said slide assembly and lead clamp assembly. said pin means being received within said elongated aperture.

16. The apparatus set forth in claim 12 wherein each of said pair of lead clamping means includes a roller engagable with the semi-cylindrical surface of said pair of shoes when they are in their operative position.

17. The apparatus set forth in claim 12 wherein said rotatable support has a generally circular outer periphery, and wherein said pair of lead clamping means each have a portion biased beyond the circular outer periphery of the rotatable support when said pair of shoes are in their open inoperative position.

18. The apparatus set forth in claim 17 wherein each of said pair of lead clamping means includes a lead clamp assembly, means pivotally securing said lead clamp assembly to said rotatable support, an elongated aperture within said lead clamp assembly remote from the means which pivotally secure the lead clamp assembly to the rotatable support, a slide assembly mounted on said rotatable support, pin means extending outwardly from said slide assembly and disposed within said elongated aperture, a roller mounted on said slide assembly and selectively engagable with said pair of shoes, and compression spring means normally biasing the lead clamping assembly and said roller to a location remote from the aperture within said rotatable support.

19. The apparatus set forth in claim 18 further characterized by the provision of a cover secured to said rotatable support, one of said rotatable support and cover being provided with a channel within which said slide assembly is adapted to reciprocate, said cover and rotatable support maintaining the slide assembly within said channel.

20. The apparatus set forth in claim 12 wherein said rotatable lead engaging means includes a gear, and said means mounted on said frame means operative to rotate said rotatable support includes a jack shaft spaced away from said rotatable support, a first relatively large diameter gear mounted on said jack shaft and engaged with said gear on said rotatable support, a second gear mounted on said jack shaft concentric with said first gear, said second gear having a relatively small diameter, a rack engagable with said second gear, and means operable to reciprocate said rack.

21. An apparatus for forming a length of twisteduntwisted leads from a plurality of leads comprising:

frame means;

lead holding means mounted on said frame means and adapted to engage a plurality of leads, said lead holding means including an aperture through which said plurality of leads may extend;

rotatable lead engaging means mounted on said lead clamping assembly;

frame means in spaced apart relationship relative a pair of shoes mounted on said frame means on opto said lead holding means, said rotatable lead enposite sides of said rotatable support for movement gaging means including v towards and away from said rotatable support bea rotatable Support rotatable about an axis, Said tween operative and inoperative positions, respec- PP having an aperture extending f tively, each of said pair of shoes having a semithrough concentric with its axis for the reception Cylindrical Concave surface engagabk with Said of a plurality of leads the apfirture m the mtat' portion of said slide assemblies when said pair of able support being in concentric alignment with the aperture in the rotatable lead engaging means, a pair of lead clamping assemblies disposed on opposite sides of said aperture in said rotatable support,

pivot means interconnecting said lead clamping assemblies with said rotatable support,

a pair of opposed slide assemblies mounted on said rotatable support for reciprocal movement toshoes are in their operative position to cause said lead clamping assemblies to be pivoted to their 0perative position;

22. The apparatus set forth in claim 21 wherein said wards and away f Said aperture on the rotatable Support, rotatable support 18 provided with a channel which reeach f i Slide assemblies including a portion 20 ceives said slide assembly, and further characterized by hi h extends outwardly f h periphery of h the provision of a cover mounted on said rotatable suprotatable support when said slide assemblies are port, said cover serving to maintain said slide assembly in their outer position, and within the channel in said rotatable support. means interconnecting the slide assembly with the

Claims

1. A method of forming a terminated pair of twisted leads from a source of twisted leads comprising the steps of: providing a source of supply of twisted pairs of leads having a free end; holding two spaced apart portions of the twisted paired leads between the free end and the source of supply and engaging two intermediate portions between the two held portions; rotating the two intermediate portions in opposed directions to untwist the leads between the two intermediate portions; feeding the untwisted leads to a cutting zone; cutting the untwisted leads at the cutting zone to form cut trailing and leading ends, the leading ends still being interconnected with the source of supply; transferring the leading ends to an applicator station for the application of terminals thereto and then repositioning the leading ends in alignment with the cutting zone; holding two spaced apart portions of the twisted paired leads between the untwisted portion and the source of supply and engaging two intermediate portions between the two held portions; rotating the two intermediate portions in opposed directions to form an additional untwisted portion; feeding an additional untwisted portion into the cutting zone while advancing the untwisted portion which has the terminals affixed to the leading ends through and past the cutting zone; severing the additional untwisted portion; and applying terminals or the like to the trailing ends of the severed additional untwisted portion.

2. A method of forming a pair of twisted leads from two untwisted leads and affixing terminals to the leading and trailing ends of the pair of twisted leads comprising the steps of: providing a source of supply for two leads in an untwisted state; twisting two short spaced apart lengths of the leads between their leading ends and their source of supply together while leaving an intermediate portion between the two twisted lengths untwisted; feeding a measured amount of twisted-untwisted wire to a cutting zone to present an untwisted portion to the cutting zone; cutting an untwisted portion at the cutting zone to form cut trailing and leading ends, the leading ends still being connected to the source of supply; transferring the leading ends to terminal applicators; applying terminals to the leading ends; repositioning the leading ends in line with the cutting zone; advancing another measured amount of the twisted-untwisted portion past the cutting zone until the next untwisted portion is disposed within the cutting zone; cutting the untwisted portion at the cutting zone to form new cut and trailing ends, the new leading ends still being connected to the source of supply; transferring the new leading ends to terminal applicators; applying terminals to the new leading ends; transferring the new trailing ends to additional terminal applicators; and applying terminals to the new trailing ends.

3. The method set forth in claim 2 in which the step of twisting two short spaced apart lengths of the leads between the leading ends and their source of supply together while leaving an intermediate portion between two twisted lengths untwisted comprises the following steps: engaging two spaced apart portions of untwisted wire and holding said portions from rotation; engaging two other spaced apart portions, said other spaced apart portions being disposed inwardly of those portions which are being held from rotation and spaced away from each other and the portions which are being held; and rotating said other portions in a common direction to twist the wire between the held portion and the other portion while leaving the leads between the two other portions in an untwisted state.

4. A method of forming twisted-untwisted paired leads from a source of supply of twisted leads so that subsequent automatic machine operations may be performed upon the untwisted portion of the twisted-untwisted pair of leads, said method comprising the steps of: providing a source of supply of twisted paired leads having a free end; holding two spaced apart portions of the twisted paired leads from rotation between the free end and the source of supply; engaging two intermediate portions between the two held portions; rotating the two intermediate portions in opposed directions relative to each other to untwist the twisted paired leads between the two intermediate portions to form an initial untwisted portion; holding two additional spaced apart portions of the twisted pair of leads between the untwisted portion and the source of supply; engaging two intermediate portions between the two held portions; and rotating the two intermediate portions in opposed directions to untwist the leads between the two intermediate portions to form paired leads having twisted-untwisted portions suitable for subsequent automatic machine operation on the untwisted portions such as the application of terminals to severed untwisted portions.

5. In an apparatus adapted to apply terminals or the like to both ends of a pair of leads which are initially twisted about each other at a source of supply, said apparatus including: leAd cutting means operable to cut a pair of leads to form an additional pair of cut leads whose trailing ends are initially in register with the leading ends of the pair of leads which still extend away from the source of supply which is located to one side of the cutting means; applying means disposed to either side of said cutting means and operable to apply terminals or the like to one or more of the cut trailing and leading ends; transfer means operable to transfer the cut trailing and leading ends from a first position adjacent said cutting means to said applying means for the application of terminals or the like thereto, and to further transfer the cut leading ends back to their first position, and feeding means disposed to the same side of the cutting means so the source of supply and operable to feed the pair of leads which are still connected to the source of supply past the cutting means after terminals or the like have been applied to one or more of the leading ends and after they have been transferred back to their first position; the combination therewith of untwisting means operable to untwist a pair of twisted leads to expose individual leads for cutting and the application of terminals or the like thereto, said untwisting means being disposed between the lead cutting means and the source of supply.

6. The apparatus set forth in claim 5 in which said untwisting means includes first and second spaced apart lead holding means, first and second spaced apart rotatable lead engaging means located between the lead holding means and spaced away from each other and the lead holding means, and first and second rotating means operable to rotate said first and second rotatable lead engaging means, respectively, in opposed directions to untwist the pair of twisted leads between the spaced apart rotatable lead engaging means.

7. In an apparatus adapted to apply terminals or the like to both ends of a pair of leads which are initially not twisted about each other at a source of supply, said apparatus including: lead cutting means operable to cut a pair of leads to form an additional pair of cut leads whose trailing ends are initially in register with the leading ends of the pair of leads which still extend away from the source of supply which is located to one side of the cutting means; applying means disposed to either side of said cutting means and operable to apply terminals or the like to one or more of the cut trailing and leading ends; transfer means operable to transfer the cut trailing and leading ends from a first position adjacent said cutting means to said applying means for the application of terminals or the like thereto, and to further transfer the cut leading ends back to their first position; and feeding means disposed to the same side of the cutting means as the source of supply and operable to feed the pair of leads which are still connected to the source of supply past the cutting means after terminals or the like have been applied to one or more of the leading ends and after they have been transferred back to their first position; the combination therewith of twisting means operable to twist two short spaced apart lengths of a pair of untwisted leads, said twisting means being disposed between the cutting means and the source of supply, said twisting means forming a pair of leads having twisted and untwisted portions, said feed means feeding untwisted portions to said cutting means and said lead cutting means being operable to sever an untwisted portion.

9. An apparatus suitable for either untwisting an intermediate portion of a pair of twisted leads or for twisting two intermediate portions of a pair of untwisted leads, said apparatus comprising: first and second spaced apart lead holding means; first and second spaced apart rotatable lead engaging means located between the lead holding means and spaced away from each other and the lead holding means; and first and second rotating means operable to rotate said first and second rotatable lead engaging means, respectively, said rotating means being selectively operable to rotate said rotatable lead engaging means in either a common direction or in opposed directions the parts being so arranged and constructed that when untwisting leads the first and second rotatable lead engaging means will rotate in opposed directions relative to each other and opposite to the twist of the leads to untwist the portion of the twisted leads between the rotatable lead engaging means and also so constructed and arranged that when twisting untwisted leads, the rotatable lead engaging means will rotate in a common direction relative to each other to form two twisted lengths between the rotatable lead engaging means and the holding means while leaving that portion of the leads between first and second rotatable lead engaging means in an untwisted state.

11. An apparatus suitable for either untwisting an intermediate portion of a pair of twisted leads or for twisting two intermediate portions of a pair of untwisted leads, said apparatus comprising: mounting structure; first and second spaced apart sub-assemblies carried by said mounting structure, each of said sub-assemblies including a frame; lead holding means mounted on each of said frames and adapted to engage a plurality of leads; rotatable lead engaging means mounted on each of said frames in spaced apart relationship relative to said lead holding means; and means mounted on each of said frames operative to rotate said rotatable lead engaging means selectively in either direction about its axis.

12. Apparatus for forming a length of twisted-untwisted leads from a plurality of leads comprising; frame means; lead holding means mounted on said frame means and adapted to engage a plurality of leads; rotatable lead engaging means mounted on said frame means in spaced apart relationship relative to said lead holding means, said rotatable lead engaging means including a rotatable support rotatable about an axis, said support having an aperture extending therethrough concentric with its axis for the reception of a plurality of leads, and a pair of lead clamping means mounted on said rotatable support on opposite sides of said aperture and movable between open inoperative and closed operative positions; a pair of shoes mounted on said frame means on opposite sides of said rotatable support for movement towards and away from said rotatable support between operative and inoperative positions, respectively, each of said pair of shoes having a semi-cylindrical concave surface engagable with said lead clamping means when said pair of shoes are in their operative position to cause said lead clamping means to be disposed in their operative position; means mounted on said frame means operative to rotate said rotatable support; and means mounted on said frame means operative to move said shoes between their operative and inoperative positions.

14. The apparatus set forth in claim 13 wherein each of said pair of lead clamping means further includes a slide assembly movable toward and away from the aperture in said rotatable support between operative and inoperative positions, respectively; and means interconnecting each slide assembly with a lead clamp assembly.

15. The apparatus set forth in claim 14 wherein said means interconnecting includes pin means mounted on one of said slide assembly and lead clamp assembly and an elongated aperture mounted on the other of said slide assembly and lead clamp assembly, said pin means being received within said elongated aperture.

21. An apparatus for forming a length of twisted-untwisted leads from a plurality of leads comprising: frame means; lead holding means mounted on said frame means and adapted to engage a plurality of leads, said lead holding means including an aperture through which said plurality of leads may extend; rotatable lead engaging means mounted on said frame means in spaced apart relationship relative to said lead holding means, said rotatable lead engaging means including a rotatable support rotatable about an axis, said support having an aperture extending therethrough concentric with its axis for the reception of a plurality of leads, the aperture in the roTatable support being in concentric alignment with the aperture in the rotatable lead engaging means, a pair of lead clamping assemblies disposed on opposite sides of said aperture in said rotatable support, pivot means interconnecting said lead clamping assemblies with said rotatable support, a pair of opposed slide assemblies mounted on said rotatable support for reciprocal movement towards and away from said aperture on the rotatable support, each of said slide assemblies including a portion which extends outwardly of the periphery of the rotatable support when said slide assemblies are in their outer position, and means interconnecting the slide assembly with the lead clamping assembly; a pair of shoes mounted on said frame means on opposite sides of said rotatable support for movement towards and away from said rotatable support between operative and inoperative positions, respectively, each of said pair of shoes having a semi-cylindrical concave surface engagable with said portion of said slide assemblies when said pair of shoes are in their operative position to cause said lead clamping assemblies to be pivoted to their operative position; means mounted on said frame means operative to rotate said rotatable support; and means mounted on said frame means operative to move said shoes between their operative and inoperative positions.

22. The apparatus set forth in claim 21 wherein said rotatable support is provided with a channel which receives said slide assembly, and further characterized by the provision of a cover mounted on said rotatable support, said cover serving to maintain said slide assembly within the channel in said rotatable support.