Patent GB-325981-A (GB)
Title: Improvements in turning-lathes and like machine tools
IPC: B23B7/16
Filed: 1929-02-04
Abstract: 325,981. Bullard, E. P. Feb. 4, 1929. Lathes.-In an automatic lathe or similar machine tool, an indexable tool-head is provided with a number of slides carrying tools which are brought successively into position to operate on work carried by a single spindle, and are fed automatically during operation, the tool-head indexing-means being stopped automatically on completion of a cycle. The machine base 20 is provided with a pedestal 21 on which is bolted a motorsupporting head 23, the latter being connected by posts 26 to the rim 27 of the base. The work-spindle 29 carrying a chuck 28 is mounted in a portion 32 of the base. A tool-carrying frame 36, having faces which carry the various tools, is indexable around the pedestal 21 and is carried on a lower roller bearing 37 and upper bearing 41. An indexing-head 42 is secured to the frame 36 and is provided with a recess 44 in which a collar 45 bolted to the pedestal is mounted. The main driving motor 48 is mounted on the head 23 and is connected through shaft 49, bevel gearing 54, vertical shaft 55, pinion 59, and gearing 60 - - 62 to a main shaft 63 provided with a friction clutch 66. Through this clutch' the drive is transferred to a pinion 68 which drives a wheel 70 from which the work-spindle and tool feed mechanism are actuated. A second pinion 58 on the shaft 55 engages a gear 71 which through a safety ratchet device 74 drives a countershaft 72 connected through further gearing to a loose gear 85 on the indexing shaft 77. A clutch plate 86 keyed to the shaft 77 is provided with a radially-movable locking-bolt 87 adapted to engage notches in a flange on the gear 85 to cause rotation of the indexing shaft. The bolt is actuated by a bell-crank 90 connected to a plate 91 which, under spring pressure, normally tends to keep the bolt 87 in driving connection with the gear 85. A lever 93, Fig. 8, pivoted at 94, has one arm 97 coacting with a stop 98 on the plate 91 and another arm is connected through a lost-motion slot 99 to a hand control 104 on a rod 100. In starting the machine, the rod 100 is pulled out, thus removing the stop 98 from the lever arm 97 and allowing the spring to engage the bolt to drive the indexing-shaft. During this movement the arm 97 is reset by the engagement of the block 98 with another lever arm 109 so that after one counterclockwise, Fig. 8, revolution of the indexing-shaft, the plate 91 is arrested to cause the withdrawal of the bolt 87 and stopping of the indexing movement. In order to effect automatic indexing when one of the tools has completed its operation, an arm 111 on the shaft 94 is adapted to be actuated to release the indexing mechanism by means of a rod 113 actuated by a cam 115 on the tool feed cam 245. The indexing-shaft 77 operates through gears 117 a crank carrying a roller engaging successively four radial grooves in the indexing-head 42, thereby rotating the tool-head a quarter-turn at each indexing operation. To hold the tool-head' rigidly in its indexed positions, the indexing-head carries locking-pins 123, Fig. 5, connecting with a spring- pressed locking-bolt 127 sliding in the collar 45. This bolt is withdrawn during the indexing movement by means of a cam 142 on the shaft 77. A second bolt 143 frictionally engages the index head, and is pressed up by a cam 150 and lever 146 to assist in locking the index head. The lower end of the index shaft 77 carries a pinion 151 driving a cam drum 154 which is geared to rotate a quarter turn at each indexing operation, or one revolution during a complete cycle of the machine. The cam is provided with two grooves 156 and 157, the latter of which is arranged to operate a lever 160 on a shaft 162 carrying a segmental gear 165 operating the main clutch yoke 167. The cam groove has three rises 157a which cause momentary disconnection of the main clutch at the completion of each indexing operation and during this disconnection the speed change is effected by the cam 156. In indexing to the loading and unloading station the clutch remains disconnected but it may be manually operated in this position to cause rotation of the spindle for ensuring correct chucking of the work. This hand operation is effected from a lever 181. The gear 70 above referred to is mounted on a shaft 182 carrying loose gears 186 - - 188 which may be selectively keyed to the shaft by a drive-key pivoted on a sliding rod 192 actuated through rack teeth 195. The gears 186 - - 188 are in constant mesh with gears 196 - - 198 mounted on a shaft 199 driving a second shaft 204 connected by spur gearing 207 to the work spindle which may thus be driven at three selectively chosen speeds. The shaft 182 is also connected by bevel gearing to a shaft 212 driving a clutch member 216 rotatable on a sliaft 217 to provide a high speed tool feed for idle movements. The shaft 204 drives through worm gearing a shaft 220 connected through ratchet mechanism to a shaft 226 carrying three gears 227 .. 229 which may be selectively clutched to the shaft by a drive-key 230 actuated from a rack rod 233. The gears 227 - - 229 are in constant mesh with gears 237 - - 239 on a shaft 240 carrying a clutch member 241 to provide the variable slow-speed tool-slide feed. A worm 243 coacting with the high and low speed clutch members, drives a barrel cam 245 actuating a rod 251 which imparts movement to the tool slides. The lever 158 actuated by the cam 154 operates a rod 254 driving a shaft carrying a pinion 259 which meshes with the rack teeth of the gear changing rods 192 and 233 so as to relate directly the particular spindle speed with the particular working tool feed. The timing of the fast and slow tool feeds is also controlled by the rod 254 through rack-and-pinion gearing which operates a sliding shaft to engage an arm 273 selectively with a number of control cams 274 - - 276 mounted on a shaft which is driven from the tool feed cam-shaft 246. An arm 269 slidably keyed on the shaft 267 is connected through lever mechanism and a quick change device to the slow speed clutch collar 253 and high speed clutch collar 252, the clutch-operating levers being connected together by a link so that the clutches are moved in unison to engage one and disengage the other. An index pointer 277a on the control shaft 277 gives an indication of the slide position. The tool-head is provided with compound tool slides on three sides, the fourth side being covered by a plate 310. A block 315 on each slide carries a roller 316 which in inoperative positions of the slide engages an annular ledge 317. In the operative position, the roller rests upon a counterweight slide 320 moving in a slideway and connected to a chain 324 passing over a sprocket 325 to a lever arm 327 mounted on a transverse shaft connected by a lever and chain 330 to a spring urged rod 331. The block 315 is also slotted to engage the toolfeeding rod 251. A lever 299 forming part of the feed clutch shifting-mechanisin supports a lever 337 engaging the cam 245. This cam carries a block which, at the end of the upward tool slide movement functions to move the high speed and working feed clutches to a neutral position. This stops the cam 245 and thus also the control cams 274 - - 276. The clutch 252 is therefore not operated at the beginning of the next operation and in order to trip this clutch the lever 288 of the clutch-operating mechanism is extended at 347 and is operated from a number of projections 352 on the cam 154 to cause the engagement of the high speed clutch 252, thus rotating the cam 245 and operating the control cams 274 - - 276 to effect the automatic speed changes. The cams 274 - - 276 are provided with adjustable cam-blocks. In order to lock the indexing mechanism and the cam 154 for adjustment or manual control a safety mechanism is provided. This consists of a slide 353 coacting with a boss 355 on the plate 91 of the index mechanism. The slide may be projected into the path of the boss by a handle 360, thereby stopping the plate 91 and withdrawing the locking bolt and disconnecting the index shaft. Mechanism for hand operation of the tool slides is also provided. A sleeve 365 operated by a hand lever 369 encloses a shaft 366 operated by a hand lever 370 The sleeve is connected through lever mechanism to a vertically sliding shaft 381 which carries bevel pinions, adapted in one position of the shaft to complete a train of gearing from the hand crank 389, Fig. 12, to rotate the cam driving worm 243. During this operation the indexing mechanism is automatically locked by operation of the index locking slide 353. The power feed clutches are also moved into neutral during the manual adjustment. Means are also provided for manual operation of the feed mechanism clutches so that during testing the fast or slow feeds may be engaged at will. For this purpose the shaft 366 carries a lever arm 405 connected to an extension of the link 287 of the clutch slifting mechanism. In order to avoid damage which might arise by manipulating this clutch mechanism during indexing, the shaft 77 carries a cam disc 414 connected by lever mechanism with an arrr. 424 which is operated at a predetermined point to separate clutch members 407, 408 and so render the hand lever 370 inoperative. The chuck jaws 35 of the workspindle are operated by power from a shaft 430 connected by bevel gearing to an extension 435 of the main shaft 63. The extension extends into an oil-pump casing 432 and drives the oil pump for lubricating the machine. The chuck mechanism may also be hand controlled by means of a lever arm operated from a hand-lever 440. At the end of a cycle the blank side. of the tool head is brought opposite the spindle at this point the machine is automatically stopped, the cam groove 157 of the cam 154 being designed so that the main clutch is not connected during the final indexing operation. A fresh cycle of operations is started by pulling out t