Patent GB-372367-A (GB)
Title: Improvements in lathe
IPC: B23B7/14
Filed: 1931-02-06
Abstract: 372,367. Lathes. JONES & LAMSON MACHINE CO., Springfield, Vermont, U.S.A.-(Assignees of Lovely, J. E. ; 25, Cherry Hill Street, Springfield, Vermont, U.S.A.) Feb. 6, 1931, No. 3839. Convention date, March 28, 1930. [Class 83 (iii).] In a lathe having headstock and tailstock members 1, 2, respectively, mounted at opposite ends of the frame 5, the central part of the frame is hollow to provide a chip space, and tools mounted for both rectilinear and rocking movements are actuated by cam members located directly beneath the headstock or tailstock. The headstock 1 carries a rotary work spindle 3 and two oscillating and traversing tool bars 6, 7 are mounted beneath the spindle at the front and rear of the machine respectively. The angular position of the tool bar 6 carrying the tool slide 8 is controlled by an adjustable former cam 15 which is supported on a carrier 16 slidable on a guide pivoted to a frame member 19, the carrier 16 being angularly adjusted by means of screws 21. The angular position of the rear tool carrier 9 is similarly controlled by a former cam 30 carried by an adjustable sliding member 31 supported by an angularly adjustable guide 32. The tool carriers are held in contact with the former cams to determine the positions of the cutting tools by means of weighted arms. The headstock carries a motor (not shown) which drives a pulley 51 mounted on ball bearings on a shaft 54, the pulley being clutched to the shaft by means of a multiple disc clutch 55 actuated by a central rod 58 through the medium of pivoted clutch dogs 60. The rod 58 extends into a sliding block 80, the block having rack teeth engaging pinion teeth on a shaft 86 which is operated against a clutch-disengaging spring by means of a starting hand-lever 87. The shaft 54 carries gears 90, 91 engaging gears 92, 94 respectively, to impart a two-speed drive to a shaft 93 which carries a gear 125 driving a parallel shaft 127 connected by gears 145, 146 to the work spindle. The gears are selectively engaged by means of clutch dogs 97 which operate friction clutches 100, 101, the dogs being operated by a rod 102. The low-speed drive is associated with ratchet mechanism which is overrun when the high-speed drive is in operation. The clutch-actuating bar 102 extends into a block 130, having rack teeth actuated by a pinion on a sleeve 133 journalled on the rock shaft 86. This sleeve is rotated by means of a rack rod connected through lever mechanism with an actuating hand-lever 140. The friction clutch incorporated in the lowspeed drive serves to prevent overrunning of the spindle when the tools are withdrawn from the work. In some cases a single speed drive for the spindle may be sufficient. Thus in Fig. 26 the drive from the shaft 54 may be through gears 150, 151, shaft 152, change gears 153, 154, shaft 127, and gear 145. The machine frame comprises a base 200, Fig. 22, with a marginal trough 201 and bottom wall 202. Hollow wall members 203, 204, 205 extend upwardly from the base and a cam drum 208 fixed on a shaft 209 is mounted beneath the headstock between the walls 203, 204. The walls 204, 205 are joined by integral front and back members 34 which support the guides for the front and back former slides, and which merge with top rails 212 supporting the head and tail stocks. The space bounded by the walls 204, 205 and the side walls 34 is left free from cam mechanism and forms a space into which chips and coolant can fall on to a perforated tray 225 from which the coolant drains to the lower wall 202 which directs the coolant to the sump supplying a pump 224, Fig. 5. Any coolant which drains into the trough 201 also flows on to the tray 225. The tool bar 6 is reciprocated axially by means of a sleeve 215 carrying a follower engaging cams on the drum 208. The sleeve is held against rocking with the tool bar 6 by means of a guiding arm engaging a guideway on the frame. The appropriate cam pieces are secured to peripheral ribs 220 on the drum. On either side of the cam drum are mounted guide shafts 230, 231 carrying followers 232, 233 which are guided at 236 and co-operate with cams on the main drum. The followers are connected through adjustable rods 240 to the former cam carriers to determine the angular positions of the tool bars 6, 7. A two-speed drive is provided for the cam drum 208. The high-speed drive is obtained from the shaft 54 through bevel gearing 251, shaft 252, vertical shaft 256, coupling 257, bevel gearing 261, high-speed clutch 270, and worm gearing 264. The clutch is operated by a yoke actuated automatically through lever mechanism from a cam drum 499 fixed to the end of the main cam shaft 209. When the clutch 270 is disconnected the cam shaft is driven at the low speed from the work spindle which carries a bevel gear 300, Fig. 18, driving through a horizontal shaft 302 and bevel gearing 303 a vertical shaft 305. The latter shaft drives the worm shaft 263 through change gears 311, vertical shaft 316, safety coupling 317, bevel gearing 330 and overrunning clutch 332 so that when the high-speed clutch is engaged, this drive may overrun the slow drive. The coupling 3 embodies a pin 320 which is sheared if the resistance to the drive becomes excessive. In order that the cam shaft speed may immediately fall when the high speed is disengaged, the shaft 263 carries a brake drum 340 engaged by a friction band held by a ring 342 having a foot portion engaging a recess 344 in the casing. In a modification, Fig. 9, the friction material 352 is held against a flange 351 on the brake drum by means of a spring- pressed ring 354. The end of the worm shaft 263 is squared at 363 for operation by hand. The coolant pump 224 is driven from the shaft 256 through bevel gearing 372 and coupling 370. Means are provided for quickly bringing the parts to rest on actuation of the stop lever 87. For this purpose the lever shaft 86, Fig. 2, is connected through an arm 88 and link 383 to brake mechanism comprising a band 381 engaging a pulley 380 mounted on the shaft 252 forming part of the high-speed driving train of the cam shaft. The machine may also be stopped automatically by a stop cam on the main cam shaft which at a predetermined time engages a lever which through a vertical rod 393 and rock-shaft actuates an arm 396 carrying a latch piece 397 coacting with a similar latch 398 on the starting lever 87. When the rockshaft is in its normal position the latches interengage and prevent the spring 90 from disengaging the main clutch, but when the stop cam operates, the latches are disengaged and the starting lever is thrown to stop the machine. The rod 142 controlling the spindle speed change may also be automatically operated from the cam drum through a bell-crank lever 399. The rear tool bar 7 is reciprocated axially by means of a lever 403, Fig. 32, engaging between collars 400 on the tool bar. The lever is pivoted at 404 and the lower end is pivoted to a block secured to a follower carrier 409 having a follower actuated by a cam on the main cam drum. The carrier is guided on the bar 231. For taper turning the tool bar 7 is moved angularly during its reciprocation. For this purpose the tool bar carries a collar 450, Fig. 36, having an arm carrying a roller 452 riding in a space between adjustable segmental guide blocks 454. The guides are mounted on a disc 456 which is angularly adjustable in a clamping ring 460 carried on a fixed bracket 461. Thus during the reciprocation of the bar 7 the bar is rocked to an extent depending on the setting of the segmental blocks 454. In some cases a third tool bar having either axial or rocking motion or both may be required. The bed may then be provided with walls 500, 501, Fig. 29, in place of the single wall 205. The cam shaft 502, Fig. 30, is extended to pass through the walls 500, 501 and carries a cam drum 505, Fig. 29, which may be provided with a cam which acts through a lever 518 to reciprocate the tool bar 7. The auxiliary tool bar 510 has an oscillating movement only and may be actuated by means of a cam 525 through the lever mechanism shown in Fig. 30. The tool bar 510 may operate a set of facing tools 550, Fig. 31, for turning shoulders on the workpiece while roughing tools 551 and finishing tools 552 are provided on the carriages 8, 9 respectively. By the use of suitable former cams the tools carried by the front and back tool holders may be relieved from the work on the return strokes. In another modification the tool bar 510 has a reciprocating as well as an oscillating motion. In this case the tool bar 7 carries a sliding sleeve 600, Fig. 40, having an extension 603 which is clamped to the bar 510, the sleeve 600 being moved axially through a lever 610 and a rod 615 operated by a cam mounted either on the main cam drum or on the auxiliary cam drum 505. The angular position of the bar 7 may be controlled by a former slide on the member 16 and the bar 7 also controls the angular position of the bar 510. For this purpose a member 624 secured on the bar 510 has a follower 622 engaging a camface secured to the bar 7. Thus if the bar 7 is rotated clockwise in Fig. 41, the follower passes on to the cam portion 621, thus relieving a tool 640 carried by the auxiliary tool bar for a return traverse.