Patent GB-921777-A (GB)
Title: Improvements in lead-making methods and machines
IPC: B21D43/04
Filed: 1959-07-02
Abstract: 921,777. Making electrical leads; shearing; stamping. AMP Inc. July 2, 1959 [July 15, 1958], No. 22766/59. Classes 83 (2) and 83 (4). [Also in Group XXXVI] A method of making electrical leads comprises advancing wire stock a distance equal to the length of a lead, severing the lead length, cutting the insulation at the trailing end of the lead and the forward end of the wire stock, moving the ends axially to strip the cut insulation and then swinging the ends sideways and crimping connectors thereon. Insulated wire from a reel is continuously measured and fed by a device 1 to a pair of feed rolls 142 which are intermittently frictionally driven by rolls 156. The wire is then held by clamps 184, 182 in a carrier 6 and by a clamp 343 in a carrier 6<SP>1</SP> while blades 3 are closed to cut off a lead length of the wire and blades 5 are closed to cut through the insulation. Carriers 6 and 6<SP>1</SP> then move apart and away from the blades which act as strippers to remove the severed insulation and are then rotated to position the stripped ends in crimping presses 484, 484<SP>1</SP> where connectors are attached. The carriers are then turned back again, the clamps opened and the lead ejected. Meanwhile, the device 1 has been measuring and feeding another lead length which accumulates as slack ready to be rapidly advanced by the rolls 142 at the beginning of the next machine cycle. The measuring and feeding device 1 is as described in Specification 921,778. The slack equivalent to the length of the lead to be made accumulates between the device 1 and the feed rolls 142 which are urged together by a spring and frictionally driven by fibre tyres on driving rolls 156 keyed to shafts 158 driven by motors through flexible shafts 162 and slip clutches 160. The feed is stopped by clamping the wire and as the carriers 6 and 6<SP>1</SP> are moved to strip the insulation from the ends of the lead and wire, cams move the rolls 156 out of engagement with the rolls 142. Each clamp 182 and 184 comprises an upper part 186 with centrally notched depending flanges 188 and a lower part 190 with a central trough along which the wire is fed and with slots to receive the flanges 188. Securing bolts 198 and guides 194 extend between the parts which are biased open by springs 196. Bell crank levers 200 which bear on the undersides of extensions 203 of the parts 190 are coupled by a rod 210 to the arm 214 of another bell-crank lever, the other arm of which is actuated by a cam 232 on a continuously rotating shaft 234. Normally the clamps are kept closed by a spring 220 acting on the rods 210 through a rod 218 but when cam 232 acts to raise rod 210 against spring 220, the clamps are opened by springs 196. The feed rolls and the clamps are mounted on a slide 146 which carries a roller engaged by a lever 242 pivoted to an adjustable bracket 244 and adapted to be oscillated by a rod 252 through a bell crank lever, one arm 260 of which carries a roll 262 engaging another cam 264 on the shaft 234. Each revolution of the cam moves the slide 146 to the left, as seen in Fig. 9A, against a spring 238, the retraction being in two steps, the first to strip the insulation and the second, after crimping, in order that the connector will clear the crimping press. After the first retraction the carrier 6 is rotated through about 25 degrees and to this end the gibs of the slide 146 are rigidly mounted on a hollow spindle 266 to which is keyed an extension 265 carrying at its lower end a hub 272 with an arm 271 connected by a link 278 with a pivoted lever 282 which is oscillated by a cam 288 on the shaft 234. While the carrier is in the rotated position it is depressed to position the stripped end of the wire in a connector already positioned in the crimping press, the depression being effected by a cam 310 on a shaft 312 which engages a pivoted bifurcated lever 304 connected to a collar 298 surrounding the hollow spindle extension 265. The carrier 6<SP>1</SP> is actuated in a similar manner to the carrier 6, but it has no feed rolls and only a single clamp associated with a bell-mouthed guide tube 340 and comprising two pivoted jaws 344 biased apart by a spring 348 and closed by a wedge 352 at the end of a lever coupled to rods 210 and 218 as in the case of the lever operating the clamps on carrier 6. When the jaws 344 are opened after a connector has been crimped to the trailing end of a lead, a jet of compressed air blows the completed lead out of the tube. Shearing.-A pair of similar housings 366, 366<SP>1</SP> held between top and bottom plates 365, 367 have lower and upper guides 364a and 364b for a lower die 360 and an upper plate 388 respectively which form the wire severing blades. The die 360 has a central opening to receive the blade 388 and is connected to a T-lever 370 pivoted to an adjustable slide 374 and operated by a cam 386 on the shaft 312. Adjustment of the slide in a bracket varies the travel of the die. The blade 388 is actuated from a pivoted lever 396 connected by levers to another cam 416 on the shaft 312. When the blade 388 descends a short length of wire is removed. Cutting of the insulation is effected by lower knives 418, 418<SP>1</SP> and upper knives 444, 444<SP>1</SP> reciprocable in guides formed in plates 422, 422<SP>1</SP>. The lower knives are connected by links to a bell-crank lever 430 pivoted to an adjustable slide 440 similar to the slide 374 and oscillated by a cam 436 on shaft 312. The upper knives are connected by links 448, 448<SP>1</SP> to pivoted levers 450 actuated by the lever 404. The insulationcutting knives remain closed while the slides retract to strip the severed ends of insulation which are then removed by a compressed air jet. Lateral adjustment of the position of the knives so that the length of insulation removed can be varied for different sizes of connectors is effected by upper and lower wedges 458<SP>1</SP>, 459<SP>1</SP> on each of the guide plates 422, and 422<SP>1</SP> co-operating with movable wedges 462<SP>1</SP> slidable within the housing 366<SP>1</SP>. Crimping.-Each crimping press comprises a frame 484 having at the top an eccentric 504 on a shaft 486 driven by a sprocket and chain. Around the eccentric is a hub 506 connected by a ball and socket 510 with a ram 512 reciprocable between gibs 514. To the ram are secured a blade 518 for removing the connecting tag between connectors, a wire crimping die 520 and an insulation crimping die 522. The strip of connectors is fed along a channel in a block 526 beneath a resilient hold-down plate 533 by a finger 540 pivoted on an ear 542 depending from a plunger 536 which is moved in the feed direction against a spring 546 by an adjustable screw 551 in another plunger 550. As the ram 512 moves, a cam follower 568 carried thereby moves a cam track 566 secured to a slide 564 coupled by a lever 552 with the plunger 550 which is thus reciprocated to feed the string of connectors. Specification 921,779 also is referred to.