GB508639A - Improvements in or relating to machine tools, for example gear shapers - Google Patents

Abstract

508,639. Gear-cutting. SYKES, W. E. Oct. 29, 1938, No. 31329. [Class 83 (iii)] A machine tool such as a gear-shaper has in-feed mechanism for the work-saddle comprising a spring-biassed control-block which is fed intermittently against the biassing means, the block being released on completion of the feed and returned by the biassing means to its original position. As applied to a gear shaper of the pinion-cutter type the base 30 carries a narrow column 31 providing a timing gear compartment closed by a door 34 for giving access to the gearing and for facilitating the supervision of a battery of machines by a single operator. The top of the column carries a gear housing and a motor 44 connected by belts to a shaft 40 which actuates the means for reciprocating the tool-spindle and also drives a countershaft 58 connected by bevel gearing 154, shaft 155, and changegearing 156 to. a shaft 157. This shaft drives a gear 159 on a worm shaft which imparts rotary generating movement to the work. Shaft 157 also drives through change gearing 156a and gears 163, a splined spindle 150 carrying worm 174 driving a worm wheel 175 on the work-spindle 180 carried in a slidable saddle 170. The spindle has thrust surfaces at 170b and 171b and carries a table 177 for mounting the blanks which may be carried on an arbor secured in the bore of the spindle. The upper end of the arbor may be carried in a tailstock which includes a base secured to the saddle and provided with vertical pins 192 having rack teeth 192a and carrying a yoke 193 fitted with a cross shaft 194 which carries gears meshing with, the racks. The yoke has a bearing surface 199 for a dead centre 200, which is secured by a clamping strip 202 and bolt 204a. The centre is axially adjusted by a screw 206. In-feed of the work to the cutters is effected by a rod 210 adjustably secured to the saddle and extending into the unit F where it is secured to a cam block 222 having a cam surface 233 engaging in a complementary slot in a control block 230, Fig. 7, which is guided in a housing 220 and is normally urged to the left, Fig. 5, by springs 235 and locked against such movement by a pair of rollers 237, 237a engaging a surface 230a and a member 238. The rollers are urged into locking position by a spring-pressed plunger 239 and may be released by a finger 240. When the control block is moved to the right the cam block 222 is actuated to feed the work to the cutters. For this purpose the shaft 150 drives a cam-shaft 246 carrying a cam 246a which operates a pawl 261 imparting intermittent movement to a ratchet wheel which is integral with a disc 262 having slots to receive rollers 265a, 266a. The disc also carries a cain insert 267. The roller project at different radial distances from the centre of the disc and they successively engage the end of the control block to impart a feed step thereto, the final or'finishing feed step being imparted by the cam 267 which also pushes back the releasing plunger 240 so that after the cam 267 has left the control block the springs 235 can return the control block immediately to the left to withdraw the work. As the block returns it strikes a spring plunger 270 and actuates a switch 272 to stop the motor 44. To reset the parts the disc 262 is turned manually to release the plunger by means of a pinion engaging a gear secured to the control disc. Specification 508,638 is referred to.