Patent GB-462770-A (GB)
Title: Improvement in lathe
IPC: B23B7/12
Filed: 1936-01-29
Abstract: 462,770. Lathes. JONES & LAMSON MACHINE CO. Jan. 29, 1936, No. 2730. Convention date, Jan. 29, 1935. [Class 83 (iii)] A lathe is provided with a traversing carriage the speed of which is automatic. ally reduced immediately before the limit of travel. The headstock 3 is driven through a change speed gearing from a motor 5 and the ways 2 support a turret saddle 10 fitted with a turret 11. The saddle may be traversed at high speed from a shaft 15 driven from a motor 16 through reduction gearing 26 and friction clutch 30. The shaft 15, Fig. 22, carries a splined sleeve 40 held against axial movement in the saddle apron and connected by gearing to a high speed clutch element 51 and low speed clutch element 49 the two speeds being selectively engaged by a clutch 60 on the shaft 50. The latter is connected through reversing bevel gearing 73 to a shaft 70 carrying a pinion 71 which engages a stationary rack bar 72. The reversing clutch member 76 is controlled from a hand lever 86, acting through shafts 85, 89, on a dog member 90 having a block 92 actuating a rocker 94 secured to the shifter arm of the clutch 76. The speed clutch 60 is normally held in low speed position by a spring abutment 101, Fig. 28, but may be moved to high speed position by a lever 105 carrying a roller 110 actuated by faces 111, 112 on the dog 90. When the lever 86 is moved away from its neutral position the reversing clutch is shifted to withdraw the saddle while the low speed remains operative. Further movement of the handle moves the parts to a position, Fig 30, wherein the cam surface 111 moves the arm 105 to engage the high speed while the low speed drive is overrun. As the saddle approaches its outer limit the dog 90 which moves with the saddle is rocked by the engagement of a pin 91 with the nose 126 of a fixed cam bar 120 and moved to a position wherein the low speed is again engaged and the saddle continues its movement until a shoulder 125 on the cam bar engages the pin 91 and restores the parts to neutral position Fig. 28, by disengaging the reversing clutch. Downward movement of the handle 86 similarly moves the saddle towards the headstock, first at low speed and then, on farther movement of the handle, at high speeds. As the turret approaches the work the automatic feed drive is brought into engagement. This is driven from the work spindle 4 which carries a gear 150, Fig. 23, connected through a spur gear train to a shaft 170 extending into a sleeve 1750 connected by a six-speed gearing to a shaft 192 driving a worm wheel 194 carrying spring pins 201, Fig. 12, which normally maintain a clutch element 202 in disengaged position. The clutch element 202 is connected to a pinion-shaft 208 engaging a stationary rack 210. An arm 212 is mounted on the outer end of shaft 195 and coacts with balls 228 and pins 215. When the arm is in its normal raised position the balls are moved forward by a notched cap member 220 so that the pins maintain the clutch 202 in engaged position, the arm being held in this position by latch mechanism including a latch pin 230. When this pin is retracted the lever arm 212 drops and the clutch 202 is disengaged. This action occurs automatically when the saddle reaches its desired position by means of a pin 255 actuated by a release bar 260, Fig. 20. The bar is cut away at one end for engagement by a rock-shaft 264 coacting with a series of drop fingers 270 six of which (one for each turret position) coact with fixed control bars 273 and three with fixed control bars 273a. Each bar has a slotted portion 274, Fig. 10, with a stop surface 275 and the turret drop fingers are slotted to receive latch fingers 278 bearing on cut-away portions 286 of an indexable selector shaft 285 which is rotated one sixth of a revolution at each indexing step, as the turret saddle moves forward. When the latch finger which is beneath the cut out 286 corresponding to the turret position is allowed to drop by the drop finger 270 reaching a slot 274, the drop finger is rocked to the dotted position in Fig. 10, thus rocking the shaft 264 sufficiently to actuate the release bar 260 to release lever 212 and disconnect the feed clutch 202. The drop fingers are returned to their raised position on retraction of the saddle. To change the limit of forward motion of the saddle the desired drop finger is prevented from dropping by means of a shaft 321, Fig. 10, rotated from a knob 322. The control is then effected by one of the additional drop fingers 270a which is allowed to descend into its notched bar by appropriate cut-outs parts of the shaft 321. The saddle may also be actuated by hand from a wheel 350 acting through shaft 351, clutch 3520 and a gear on the pinion shaft 208. The clutch 3520 is automatically disengaged whereever the high speed drive shaft 15 is operative to move the saddle. The tuiret carries a notched indexing disc 400 engaged by a cam follower 402 on an arm 403 and normally pressed into looking position by a spring pressed arm 406. The spring mechanism comprises a hollow post 409 forming a turret locking pin and the follower 402 serves to hold the pin away from the turret until the indexed position is reached. The arm 403 is also secured to another arm 420 coacting with a cam 422 to withdraw the locking pin prior to indexing. The cam 422 is mounted on a plate 423 coacting with a block on a bar 426, which produces the turret indexing movement. Towards the end of the withdrawal movement of the saddle a hook 440, Fig. 1, engages the end of the bar 426 and moves it forward so that the cam block 422 actuates sleeve 404 to withdraw the locking pin 409. A block 425 on the bar 426 carries an indexing pawl 446 coacting with an index disc 448 beneath the turret to effect indexing as the bar 426 is moved forward. Prior to indexing the turret clamping means is released. This consists of a two-part annular ring 460, 461 secured together by overlapping slotted links 467, 468 actuated by a member on a gear segment 475 engaging a similar gear segment 476 provided with a cam follower running in a cam slot to the block 425. When the bar 426 moves forward the parts are moved to the Fig. 7 position to release the clamping members 460, 461. At the extreme position of the turret saddle a latch hook 438 thereon engages over hook 440 thus holding back the bar 426 when the saddle moves forward restoring the indexing parts to normal positions and reclamping the turret. The hook is finally automatically released. The coolant for the turret tools passes through pipe 301 having a slot 501, Fig. 5b which registers successively with radial passages 502 in the member 11. These passages may either be plugged or connected to suitable points above the respective tools. Thus as the tools are indexed to operative position their coolant supply is automatically turned on and is turned off again when the tool leaves the operative station.