Patent GB-448369-A (GB)
Title: Improvements in lathe and the like speed control mechanism
IPC: B23Q5/00
Filed: 1935-07-20
Abstract: 448,369. Lathes. JONES & LAMSON MACHINE CO., Springfield, Vermont, U.S.A. July 20, 1935, No. 20716. Convention date, Aug. 7, 1934. [Class 83 (iii)] [See also Group XXIV] In a change-speed gearing for lathes &c. at least three shafts with intermeshing gears are arranged in a single train one shaft being a driving shaft and one a driven shaft and a single operating means is provided for shifting the gears in such manner that the geared connection is interrupted only between two shafts at any time when shifting from one gear to any other gear. The bed 1, Fig. 19, carries a headstock 2 and the longitudinal ways 5 carry a sliding turret saddle 3, fitted with a turret 4, and a longitudinal tool carriage 6 fitted with a cross slide 7 provided with a tool support such as the manually rotatable tool turret 8. A feed shaft 12 driven from the headstock spindle 20 through a gear train 15 .. 19 passes through the aprons 10, 11 of the turret saddle and tool carriage respectively. The spindle 20 is driven from a main shaft 30 which drives a shaft 31 either forwardly through gears 32, 33 or reversely through gears 35, 36, 37, this gearing being controlled by clutches in the casings 34, 38. The shaft 31 is connected to the shaft 40 through change speed gearing comprising a gear pair 42, 43, Fig. 13, engageable selectively with gears 45, 46 on the shaft 40. The shaft 40 also carries a loose connected pair 47, 48 and a fixed gear 49, the gears 48, 49 engaging respectively with gears 56, 55 on a back gear shaft 41 so that gear 47 rotates at lower speed than gear 49. A shaft 50 carries a sliding pair 52, 53 of which 53 may engage either of the gears 47, 49 while 52 may engage the gear 46, giving three speeds of the shaft 50 relatively to shaft 40. Another sliding pair 61, 62 on a sleeve carried by the shaft 50 are selectively engageable with gears 63, 64 on the spindle 20, a neutral position being also obtainable. The various gear pairs are controlled by levers actuated in the manner similar to that described in Specification 439,948, [Group XXIV]. The sleeves 44, 51 and 60 of the sliding gear pairs are actuated by pivoted levers 70, 80, and 90 respectively. The lever 70 is pressed down by a spring ball in a hollow plug 76 which coacts with projections 77, 78 to determine the limiting positions of the levers. The lever 70 is actuated by a segmental selector 104, Fig. 5, coacting with fingers 115 on an annular rocker 110 connected by a slotted arm to the lever 70. The levers 80 and 90 are similarly mounted, and each has three positions determined by segments of different heights on its selector. The selectors are all mounted on a shaft 103 which carries a notched disc 135 coacting with a spring-pressed ball to determine the positions of the shaft. To permit free turning of the selectors they may be moved axially out of engagement with their rockers. For this purpose the shaft 103 is connected at 154 to a hand lever 152 which is rocked about its pivot 151 to withdraw the shaft 103 and may then be turned to position the selectors for the required speed before returning the shaft 103 to engage the selected speed. The speeds are indicated on a dial 165 coacting with a pointer connected to shaft 103. The outer faces of the selectors are of different axial lengths so that the rockers are moved at different times during the axial motion of shaft 103 ; the sliding gears are thus sequentially operated so that there are never two points of disconnection in the gear train at the same time. Figs. 13 and 18 show respectively the positions of the gears at the beginning and end of a change from the lowest to the highest speed. The tool slide feed is derived from gearing coacting with the rack 25. For manual feed a hand wheel on a shaft 204 operates a gear 200 geared to the rack. For automatic feed, a gear 202 is connected through pinion 206, clutch 208, 209 and worm gearing 211 to a shaft 221 driven through change speed mechanism from the shaft 12. The worm wheel 211 is also secured to a gear 212 connected through pinion 214 shaft 215, clutch 216, gears 218, 219 to the cross feed screw of the tool slide. The clutches 208, 216 serve respectively for the disconnection of the traversing and cross feeds at the desired limits of travel. The gear change mechanism of this feed train comprises gears 222 .. 224, Fig. 33, mounted on shaft 221 and coacting selectively with gears 225 .. 227 on a sleeve 228 slidable on splined shaft 229. Another sleeve 235 on this shaft carries a sliding pair 236, 237. The gear 236 coacts with either of the gears 241, 242, the former being fast on shaft 243 and the latter loose thereon, and connected through back gearing 244, 245, 247 to a gear 246 on shaft 243, which is driven from the shaft 12 either directly or through a reverser shaft 252. This reversing mechanism is actuated from a handle 255. The sleeves of the feed change speed gearing are operated by rods, Fig. 33, actuated by segmental selectors, coacting with annular rockers 269, 282 in a manner similar to that described for the spindle driving train. The spindle 273 carrying the selectors is moved axially by a handle 299 and a dial 303 indicates the selected gear. The selectors and rocker fingers are as before so related that the driving connection is interrupted only at one point at one time. The manual stop mechanism for the tool traverse may be similar to that described in U.S.A. Specification 2,006,144. The clutch parts 208, 209 are constantly urged apart by spring- pressed pins 401, Fig. 24, but are kept together by a lever 407 whose hub carries a cam ring 409 notched at 411 to receive balls 412 which are normally seated on the flat periphery of the cam so as to maintain the clutch sleeve 208 in engaged position. The lever is latched in this position by a pin 420 engaging a recess in a member 423, but by rocking a handle 430, balls 432 are cammed out of recesses in the handle so as to withdraw the latch pin 420 and allow the lever 407 to drop, whereupon the balls 412 drop into the notches 411 and the clutch is withdrawn. For automatic stoppage of the feed, a release pin 450 coacts with a lever 455 which may be actuated by a stop block 458 carrying a number of abutment plugs 459, any of which may coact with a stop 460, Fig. 19, and operate the release pin to disengage latch 420 and stop the feed. The clutch 216 in the cross feed train may be similarly actuated. In this case the feed may be stopped at either limit of motion, the stop block 470 having abutments at each end, Fig. 24a, and acting through a bell-crank lever 472 to move the release pin 477. The traversing motion of the turret saddle may be actuated from the feed shaft 12 in a manner similar to that described for the tool slide traverse, the selector mechanism being shown at 500, Fig. 19. The stop mechanism for the turret traverse embodies a hand release handle 506, Fig. 23, and the automatic release may be actuated by a lever 507 operated through push rod 510 and rock shaft 511 having a cam face coacting with stop bars 513 in the manner described in U.S.A. Specification 771,242.