Patent GB-356326-A (GB)
Title: Improvements in a method and a device for controlling motions, particularly in machining solid materials
IPC: B23B7/12
Filed: 1930-06-16
Abstract: 356,326. Actuating slides of machine tools &c. SCHENKER, M., Seh÷nenwerd, Switzerland. June 16, 1930, No. 18373. Convention date, June 19, 1929. [Class 83 (iii).] Lathes.-Moving parts such h as the slides of machine tools are controlled by means of a record such as a punched sheet 21, Fig. 88, which serves to set a counter to the number of units of movement required, the motion being automatically stopped when the set movement has been effected. In an application to a turning- lathe the machine comprises a headstock 12 and tailstock 13 mounted on a bed 1, and a turret tool holder 10 having tools 11 is mounted on a slide rest consisting of a longitudinal slide 4 and a cross slide 7. The longitudinal movement is derived from a leading-screw 5 and the transverse movement from a splined shaft 189 which operates through bevel gears 190, vertical shaft 194, bevel gears 193, and screw 8. The machine is driven from a pulley 26 which carries a spiral gear 27 connected through a vertical shaft 29, and the gear trains shown in Fig. 3 to drive a series of control shafts, comprising a shaft 23 controlling the spindle change-speed mechanism, a shaft 19 controlling the tool turret, a shaft 15 controlling the counting train of the longitudinal feed, a shaft 17 controlling the counting train of the transverse feed, a shaft 18 controlling the speed of the feed. and a main control shaft 221 actuating the intermittent feed of the record 21. The driving pulley is loose on a countershaft 48 and is connected thereto by a friction clutch 49, Fig. 18, controlled by a lever 50 operated by a cam 90 on the control shaft 23. This shaft comprises the continuously driven part 23 connected to an aligned portion 23<1> by a coupling comprising a recessed collar 771, Fig. 40, on the part 23 and a ring 79 which is mounted on the part 23<1> and is slotted to receive rollers 81. A ring 82 having limited angular movement on the ring 79 is provided with recesses 85 accommodating part of the rollers and a projection 86 which normally engages a pawl 87 to hold the coupling m disengaged position, Fig. 39. When the pawl 87 is tripped by a Bowden wire control D, the pawl is withdrawn and the ring 82 is shifted by springs so that the coupling is locked to drive the shaft 23<1> through one revolution. All the control shafts are provided with couplings of this type actuated by Bowden wire mechanism. The countershaft 48 carries loose gears 52 .. 55 engaging gears 56 .. 59 respectively on the spindle, the gears being selectively engaged to impart a four-speed drive to the spindle by means of splined coupling members 60, 61 provided with spring coupling pins 62 and controlled from the shaft 231. The spindle 24 carries a brake drum 69 coacting with a band 70 actuated from the shaft 23<1> through cam 122, rod 72, and a bellcrank lever. The spindle also carries a sprocket 73 for driving the feed motions. Each of the coupling members 60, 61 is actuated by a cam 95 having guide grooves 96, 97, Fig. 32. These grooves co-operate with rollers 98 carried by coupling elements comprising catch bolts 100<11>. When a lever 991 is rocked by a Bowden control C, the corresponding catch bolt is released, Fig. 23, and engages a projection on a lever 120<1> which is rocked from a cam 116 on the control shaft, Fig. 31. The roller 98 is thus forced into the groove of the cam 96 or 97 and the shaft 67 is then oscillated to effect the required speed change of the spindle. On the return oscillation of the lever 1201 the roller 98 is withdrawn from its cam and the catch bolt 100<11> returned to its latched position. The friction clutch 49 is disconnected by its cam while the spindle speed changes are effected. The Bowden cables are constructed as shown in Fig. 34, the covering being secured by studs 127 and the central wire being secured to end members 128. The control shaft 19 of the turret is also provided with a roller coupling of the type described above, the movements of the driven part 19<1> being transferred to the turret through bevel gears 132, 134, Fig. 6, shaft 135, bevel gears 136, coupling 409, and worm gearing 138. The control of the turret rotating mechanism is shown in Fig. 12. The coupling 130 is normally held disengaged by an abutment 146. A shaft 143 driven at a quarter of the speed of the shaft 191 carries axially staggered projections 144 corresponding to each turret position and each coacting with a catch lever 158 and with levers 156 controlled by a set of Bowden cables A. In order to change the operative tool, the lever 148 is tripped to the position shown in Fig. 12 by the Bowden wire B. Simultaneously the wire A corresponding to the required tool is also operated. The shafts 191, 143 are now driven and the turret rotated and when the desired tool has been brought into position the corresponding projection 144 engages its lever 158. which then acts through levers 156, 152 to bring the abutment 146 into position to disconnect the coupling 130 and stop the turret rotation. The feed motions are derived from the sprocket 73 on the spindle which drives a feed control shaft 76, Fig. 41, carrying loose gears 161, 162 selected by a splined pin-coupling member 163 and engaging gears 164, 166 on a countershaft carrying a splined pin-coupling 169 controlling forward and reverse drives to a shaft 170 connected to a shaft 173, which imparts through chain gearing a two-speed and reverse drive to a sprocket 179, Fig. 1, operating the longitudinal feed and a similar drive to a sprocket 180 operating the transverse feed. The speed changes are controlled from the shaft 18 which has a roller coupling 161<1> operated by a Bowden wire F. The part 18<1> also carries cams which co-operate with members 163<11>, 164<11> controlled by Bowden wires E, G, the control being similar to that described in connection with the spindle speed-changing mechanism. The sprocket 179 is carried on a shaft 181 provided with a doubleroller coupling 182, Fig. 44, and connected by gears 183 to the lead screw 5, Fig. 1. The sprocket 180 for the cross feed is similarly connected to the splined shaft 189. The ring 202 is provided with two sets of roller recesses 208 and the rollers in the disengaged position fall into one or other pair of recesses according to the direction of rotation. The coupling is controlled by pawls 209 engaging two sets of ratchet teeth facing in opposite directions. When the ratchet ring is engaged by one of the pawls the coupling is disconnected but when the ring is released it is shifted by springs to cause engagement of the coupling and drive of the feed shaft. The shaft 181<1> is connected to a gear 223 of the counting train of the longitudinal feed, Fig. 56. The drive is transferred through bevels 227 to an indicator drum for units. A tens-transfer mechanism 225 drives a wheel 230 connected to an indicator drum for tens and a further similar tens transfer mechanism is connected to an indicator drum for the hundreds. To adjust the indicator drums the gear drives may be disengaged by sliding the pinions 222, 230, &c. Each indicator drum is provided for the digits 0 .. 9 with ten cam discs 235 uniformly offset along a helix and interconnected through lever mechanism, Figs. 50, 51, and 52, with Bowden wire controls M, N, 0, one control wire being allotted to each digit. The adjustment of the counting train to the number of units of feed required is effected from the main control. When the corresponding Bowden wire is actuated a lever 253 is rocked and an engagement link 242 associated with the desired units digit is engaged with a stirrup 243,244. During rotation of the counting drums, the shaft 239 is rocked by the appropriate digit cam and this shaft rocks a lever arm 245 connected to a lever 266. Similarly the " tens " digit cam and the " hundreds " digit cam of the set number actuate pawls 265 so that when the set number is reached the pawls 265 an lever 266 come into the position shown in Fig. 64 and a rod 212 is actuated to engage the pawls 209 of the roller coupling to stop the feed. The counting train may be reset to zero or adjusted to a predetermined starting number. When the rod 212 is actuated at the end of the desired feed a shaft 296 is rocked to withdraw an abutment 286 from a roller coupling device 284 to cause rotation of a control shaft 264 which carries a number of cam discs, Fig. 62, and a second control shaft 283 is controlled by a Bowden cable K through a roller coupling 284<1>. If for example a feed of 143 units is to be initiated, the counting train which has been set to some previous feed number is first set to zero. The Bowden cables M.N.O. associated with the numeral 000 and the cable K are actuated by means of punchings in the record 21. Rotation of the control shaft 283 then ensues and a cam 316 on this shaft acts through a rod 256 and stirrup 254 to disengage all the links 242. On further rotation of the control shaft the levers 248, Fig. 58, associated with the zero digits of each group are dropped and pawls 270 are thereby released and engage in zero slots 268 for the indicator drums. The drum is thus held against rotation, a slipping coupling being provided to allow further movement of the zeroizing mechanism. After setting to zero, the record 21 is advanced one step to bring the punched holes corresponding to the number 143 into position to actuate the corresponding Bowden cables of the counting mechanism. When the desired number of feed units is reached the rod 212 is actuated as previously described to disengage the feed. The counting train for the surfacing motion is similar to that provided for the longitudinal motion and is distinguished by the reference suffix a in Fig. 7, which shows the general layout of the Bowden mechanism. The punched record 21 of the main control device is guided in the casing 20 and is fed by a pawl 338 and locked by a second pawl 339. The feed is effected through lever mechan