Patent GB-314066-A (GB)
Title: Method of and apparatus for making nut blanks
IPC: B21K1/64
Filed: 1929-06-11
Abstract: 314,066. Russell, Burdsall, & Ward Bolt & Nut Co., (Assignees of Avis, S. W., and Ames, M. H.). June 23, 1928, [Convention date]. Forging nuts; dies; punches.- Nut blanks of a volume substantially equal to that of the finished nuts are perforated by displacing the metal at the centre outwards by a series of cold punching operations simultane. ously on a number of nuts held in an intermittently rotating carrier. The latter, Fig. 19, consists of a disc 98 with a series of nut pockets 140, and is located in a groove formed by adjacent faces of flanges 100, Fig. 14, of sleeves 101 passing through the punch holders 74. The flanges 100 are secured together by screws 102 and by a key 103, Fig. 16, engaging a slot 104 in the central opening 99 of the nut carrier, the whole being rotated intermittently by a sleeve, 106 keyed to one of the sleeves 101 and having teeth 107 engaging teeth on the end of a tubular stem 109, Fig. 3, carrying a ring 118 provided with a series of rollers 132 coacting with a cam 135 on the cam shaft 62. The punch holders 74 are secured respectively to a centre slide 43 and to a front slide 48, which latter is connected by tubes 50 and rods 49, Fig. 4, passing through boxes in the centre slide to a rear slide 35. The ends of the tubes 50 engage shoulders 51 in the holes 52 in the front and rear slides and the rods 49 passing through the tubes are heated before tightening the nuts 53 to put the tubes under compression when cold with the object of avoiding travel of the punch holders beyond the desired limits of their stroke. The punch holders are secured to their slides by means shown in Fig. 24 enabling them to be accurately centred, the dovetailed projection 88 on the back of the punch-holder being engaged on one side by a holding member 77 adjustable along an inclined keyway 75 and on the other side by a screw actuated wedge 85 on a holding member 81 adjustable along a straight keyway 76. The rear end and centre slides 35 and 43 are reciprocated through links 34 by a vertical slide 23 operated b a crank shaft 21 driven by an electric motor. The slides 43, 35, 23 are connected to the links by pins 47, 39, 33 but these pins are relieved of pressure during the working stroke by bearing blocks 44, 38 and 28 adjustable by wedges 45, 41, 29. Power is absorbed during the idle upstroke of the slide 23 by an air cylinder, the piston of which is connected to the slide by a bell crank and link 360, and given out during the working down stroke. Stripper blocks 89 yieldingly mounted on the front faces of the punch holders 74 are guided by pins 91, Fig., 15, screwed into the punch holders. They are pressed forwards by springs 97 and moved away from the nut carrier after the punch holders have separated a certain distance by contact of the heads 94 of the pins 91 with the guide sleeves 95. The faces of the stripper blocks are provided with rings 198 around the openings of the punches, as shown in the development diagram, Fig. 18, which rings have projecting rims 143 adapted to enter the pockets of the nut carrier to hold the latter against rotation when the stripper blocks are closed. During the punching operations lugs 141 on the stripper blocks are engaged by locks 142, Fig. 4, to hold the stripper blocks closed, the locks 142 being actuated through springs 153 by levers 148 operated by cams 150. The blanks one by one enter a space 167, Fig. 16, in one of the stripper blocks and are pushed into a pocket of the carrier by the first punch 190, Fig. 18. Thereafter, the aperture is partially formed by four punches 196, 200, 202, 204 and the nut then cupped by a die 210, being removed therefrom by an ejector rod 213 actuated by a fixed rod 218, Fig. 3. At the next station the blank is flattened and returned fully into the carrier pocket by punch 228 in readiness for trimming the aperture at the succeeding station by the punch 231 having an enlarged head 232. The trimmings are forced down a split tube 236 and discharged down a tube 240 into a container 241, Fig. 3. If the punch 231 is broken the broken part is ejected at the next station by a punch 243 and passes down the tube 240 into the same container 241. The nut aperture is countersunk at the next station by punches 248. At the last station the finished nuts are pushed out of the carrier by a pusher 251 down a tube 252 past holding springs 254 and thence through a tube 257 to the pockets of a delivery conveyer 71. Fig. 21 shows one form of blank 195 for the production of square nuts, and Fig. 43 a button shaped blank 382 preferably used for the production of hexagonal nuts, the punches used for the latter being shown in development in Fig. 40. The first three pairs of these punches 384, 388, 389 forge the blanks roughly to the hexagonal shape of the nut carrier pockets, and the others are the same as in Fig. 18. Lubrication. The working parts of the machine are oiled by splash lubrication by oil pumped by a motor 320 from a sump 305 to an overhead pipe 313 above the crank shaft and to another pipe for oiling the cam shaft 62. A separate system is provided for oiling the punches, work carrier, &c. oil for this purpose being pumped from a sump 315 to a pipe 319 above the working tools and prevented from mixing with the other oil by packing strips 325, 326, 327. In the operation of the machine oil becomes trapped by the punches in the partially formed nut apertures, as at 398, Fig. 30, and the hydraulic pressure of this oil assists in the further piercing operations. Stop-mechanism. Means are provided for disconnecting the driving means for the work carrier if the latter jams due to the breaking of a punch or the. displacement of a blank and for returning the carrier automatically to the starting station. For this purpose the ring 118, Fig. 12, actuated stepwise by cam 135, is in indirect driving connection with the tubular stem 109 by means of projections 122 on the rear face of ring 118 engaging depressions 117, Fig. 9, in the front face of a ring 115 on a disc 114 on a sleeve, 112 keyed to a sleeve 110 keyed to the stem 109, sleeve 112 being normally pressed forwards by spring 123 to hold the projections 122 and depressions 117 in engagement. In the event of jamming the sleeve 112 is forced back against spring 123 and the stem 109 and work carrier are no longer driven. Mounted on rollers 271 on the face of the fixed support 126 is a ring 270 with an annular recess 274 containing a spring 275 engaging a fixed stop 276 at one end and a shoulder 277 at the end of the recess at the other. Anti-clockwise movement of ring 270 by spring 275 is normally prevented by a spring-pressed slide 279 in a housing 280 engaging a shoulder 278. When due to jamming the sleeve 112 is forced back the disc 114 of the sleeve 112 actuates a pivoted lever 286, Fig. 10, linked to a bell crank 288 and withdraws the slide 279 from shoulder 278 on ring 270. The latter is then urged anti-clockwise, by its spring 275. Ring 270 carries a pivoted pawl 290 normally held in the position shown by slide 279 engaging a lug 202 but moved by a spring 293 when slide 279 is withdrawn or that the pawl tooth 294 engages ratchet teeth 295 on the ring 115. The anti-clockwise movement of ring 270 thus acts to give ring 115 a reverse movement which moves the work carrier back to the starting point of the cycle of operations determined by a holding pawl 296 with tooth 298 adapted to engage ratchet teeth 299 on ring 115. The ring 270 has a pocket 347 to receive a tool for moving the ring in a clockwise direction to reset the slide 279. Access to the reversing mechanism is obtained by removing a cover plate 345, Fig. 3. The release of the slide 279 also rotates a rod 343 and opens a switch 344, Fig. 4, which stops the driving motor, controls an electric clutch in the driving shaft and cuts out a solenoid to apply a brake thereto. Feeding blanks. The nut blanks in a stack 160,. Fig. 3, are moved one by one by a swinging arm 169 into a curved shoot 165, each movement of the arm pushing the lowermost blank in the shoot 165 past spring fingers into a gap in a stripper block of one of the punch holders. The arm 169 is mounted on a, pin 170, is moved backwards by a block 173 on the rear slide engaging a projection 174 on the arm and moves forwards to feed the blank under the influence of a spring 172. The stack 160 is mounted on a cover 162 which may be unscrewed from the machine casing and held in raised position on a post 182 by means of a spring pin 186 coacting with a groove 184 in the post to give access to the punch holders &c. To prevent accidental feeding of blanks when the cover 162 is raised the feeding arm 169 is adapted to be locked by a handle 180, Fig. 8, mounted on a shaft 177 carrying an arm 178 with a pin 179 engaging a lever 175 on the pivot pin 170 of the arm 169. Specifications 24833/09, 16856/11 and 124,399 are referred to.