Patent GB-470474-A (GB)
Title: Improvements in and relating to welding wires together
IPC: H01J9/28
Filed: 1936-02-14
Abstract: 470,474. Making composite leading-in wires. BRITISH THOMSON-HOUSTON CO., Ltd. Feb. 14, 1936, No. 4528. Convention date, Feb. 14, 1935. [Classes 83 (ii) and 83 (iv)] Shearing; welding.-In a machine for continuously cutting off lengths from a number of wires and electrically welding them end to end, the wires are fed to points adjacent indexed positions of a turret carrying sets of jaws for each length, and lengths from one wire are cut and then inserted in one pair of jaws and the jaws then moved away from the other stationary pair of jaws, the other wire is then inserted in the stationary jaws and a length cut off and the movable jaws then returned to weld the ends together. A three-part leading-in wire for incandescent electric lamps or radio tubes may thus be made by welding to the opposite ends of a middle section of seal wire respectively a copper and nickel wire. The turret carries a number of sets of jaws at spaced positions and may form two leading-in wires simultaneously, the turret being indexed two positions at each stage. The turret 30 is mounted on a roller bearing 37 in a housing 38 and has a cover plate 40. It carries directly pairs of centre jaws 33, and pairs of outer jaws 41, 42 are carried by rings 43, 44 secured to the turret by screw rings 45, 46 operated by internal gears 274 thereon through pinions 275 on handoperated spindles 276. The pinions are withdrawn by springs 278 after operation. The nickel and copper wires are respectively fed by mechanism mounted in standards 57, 58, the nickel wires being shorter than the copper wires and being fed at the second and third positions and the copper wires at the first and fourth positions. The two nickel wires are drawn from separate spools and pass through straightening mechanism and then round a pair of spaced sheaves 61, Fig. 5, on a shaft 64, which is intermittently rotated by mechanism with adjustable leverage. A spring-controlled adjustable brake 66, 67 is applied to a drum extending from the lower sheave to prevent overrunning. The wires then pass through a pair of rolls 82 with removable rims mounted on opposite ends of a shaft 83, which is driven by toothed gear from the shaft 64 at a slightly greater peripheral speed than the sheaves so as to draw the wires tightly about the sheaves and prevent slip. The rolls are mounted on a pivoted bracket 86 and are pressed against the sheaves by a spring plunger 94. For threading purposes, the bracket may be moved back by a hand-operated knob 106, which by eccentric pins 104 operates levers 102 engaging the ends of the shaft 83. The wires then each pass through a separate set of straightening rolls 108, 109, 110 into a flexible tube 111 secured to a member 129, Fig. 8, adjustable in a block 130 connected by a bracket 131 to a rod 47 extending from the spider 55. The wire passes between internally and externally V-notched cutter rings 121, 122, through the V-shaped toothed jaws 167 of a transferring mechanism and into a V-shaped guard 188 carried thereby. The rings are mounted in the member 129 which is adjustable by a nut 156 so as to adjust the position of the cutters. The ring 122 is mounted on a hub 123 supported on a ball bearing on the concentric portion of a shaft 126 rotated by segmental gear 152, 151 from an actuating rod. The shaft has an eccentric portion 137 passing via a ball bearing 136 through an eccentric hole in a hub 135 which is secured to a plate 134 on which the ring 121 is mounted. Cutting is effected by reciprocating the plate 134, which is prevented from rotating by a pin 138 passing through a slot in the plate 134 and through the member 129. The rings are adjustable on their hubs, when desired, by hand and are held in position by pawls on levers 142, 145, Fig. 9, connected together by a spring 148. The free end of the oncoming wire is supported by a shoe 159 on a spring- controlled arm 158 carried by the block 130. The end severed from the wire faces the centre jaws 33 and the length of the end sections of wire may thus be changed without adjustment of other parts of the machine. The transferring mechanism is pivoted at 197 on a support 191 and is operated by a rod 189 through links 192, 195 to carry the blanks to the jaws 42. The reversible V-grooved toothed jaws 167 are carried by arms 165 mounted on pivots 172 and are closed by a spring operating through an arm 182 a shaft 177, which carries a pin engaging a pair of levers 173 carried by the bar 171. The jaws are opened by an arm 199 operated from the rod 203 engaging a roller 200 in the arm 182. In order to determine the lateral position of the wires in the jaws 42 so that they line up with wires in the other jaws on the turret, a cam 204 and finger 205 take position on opposite sides of each pair of jaws 42. The cam, which adjusts the position of the jaws with respect to the centre jaws is mounted in a bracket 206 clamped to arm 207 and the finger is carried by a block pivoted on a shaft 208 in the arm 207 and operated by lever 209 through rod 210 so that the finger engages and adjusts the position of the wire. The arm 207 is mounted on a pivot 211 and held by a spring against an adjustable screw stop. The copper wires are similarly fed and transferred to the jaws 41. The jaws 42, 41 each consist of a fixed jaw 260, Fig. 13, with a detachable hard tip, secured to a block 267 pivoted on a shaft 265, and a movable jaw 261, with a hard tip, connected to the fixed jaw by a spring strip 264. The movable jaw is normally closed by a spring 285 and is opened by a rod 242 reciprocated in a bracket 229 mounted on the turret by engagement with a lever 279 connected by a link 282 to the.movable jaw. The jaws are retained frictionally in any position about the shaft 265 by securing the jaw 260 to a toothed segment 268, which is carried by the bracket 266 and engages a pinion 286 mounted on a screw 290 on an arm 291 between fibre washers 287, 288, the washers being acted on by a spring-pressed cup 292. The washers and arm 291 are mounted on a pivot 293, which carries also a spring-controlled lever 296. In order to free the bracket 266 when desired, a roller 531 on the lever 296 engages a cam 533, Fig. 1, on a bracket fixed to the housing during indexing of the turret. The centre jaws consist of a fixed jaw 220 with a hard tip and a spring-closed jaw 221, also with a hard tip, which is opened by a link 235 and lever 232 engaging a lever 238 operated by one of the rods 241. The rods 241, 242 are headed and are operated by a number of slotted blocks 245 carried by rods 249, which are reciprocated by levers 253 connected by rollers 255 to an axially moved tube 256. To prevent bending of the outer wires, they are engaged by a pair of adjustable fingers 298<1> pivoted to arms 299<1> connected to the brackets 295. At the fifth and sixth stations the outer jaws of successive heads are withdrawn to allow feeding of the seal wires to the centre jaws. This is effected by a pair of mechanisms comprising fingers 301, 302, Fig. 14, engaging blocks 312 on the jaws. The fingers are carried by rods 300 connected by cranks 305, 306 to an arm 304 and operated by a rod 314. At the eighth and ninth stations the seal wires are fed into the jaws 33. The seal wires have a coating of borax, which is scraped off at opposite sides near the ends before transfer to the jaws. The two wires are fed from spools 316 through tensioning sheaves 317 and then through straighteners 319, 320 and over sheaves 330, 331, Fig. 16, and then under rolls 340, 341 and on through separate straighteners to separate transfer, cutting and scraping mechanisms. The rolls are spring-pressed towards the sheaves and are driven at greater peripheral speed than the sheaves, the drive being through a worm and worm wheels 353. For threading purposes the rolls are raised from the sheaves by hand-operated cams 360 through levers 358. The sheaves may then be rotated by a hand wheel 370 through bevel gear. Each wire passes through a grooved guide 385, Fig. 17, and perforated block 386 of the transfer and cutting mechanism and then between a pair of annular scraping knives 387, 388, Figs. 18 and 19, carried by spring-closed jaws 389, 390 pivoted at 391, 392 in link 393. The jaws are opened by levers 394 pivoted on a plate 396. The link 393 is connected to crank 406 and lever 407 pivoted on the plate. The levers 394 are operated by a reciprocated rod 411 through pin 413 and the jaws are pulled off the end of the wire by the rod 411 to effect the scraping through a pin 416 engaging the enlargement 417 of the rod. The forward position of the jaws is determined by a stop 420, and a spring 419 between a collar 414 fixed on the rod and a loose collar 418 to cause the jaws to close before scraping is started. The scraped material is removed by a current of air drawn through holes 429. The guide 385 and block 386 of the transfer and cutting mechanism are carried by a plate 445 pinned to a yoke 448 which may swing on a pivot 450 on an arm 447. The arm 447 carries an inclined cutter 468 and supports a lever 451 which is connected to the plate 445 and is oscillated by a crank 471 on a shaft 472 operated by a rod 473 and link 474. The arm 447 is carried by a. yoke 454 pivoted at 455 to a yoke 456. The transfer mechanism is moved on its pivots 455 to place the wire in the centre jaws prior to cutting, by a reciprocated rod 459, link 461 and, rod 462. The link 461 is carried by a micrometer adjusted slide 463 to vary the position of the rod 459 and thus the extent the wire passes into the jaws. This is also determined by discs 433, 434, each mounted on an arm 435 pivoted at 436 in a yoke 437 pivoted at 438 in a bracket. The discs are swung by springs 441 into contact with the jaws when the rod 411 completes its movement to the right and are returned by collar 439 engaging arms 435. Adjustment of the yokes 437 by a micrometer gear 442 varies the position of the discs. Cutting is then effecte