Patent GB-642918-A (GB)
Title: Improvements in or relating to boring machines, and particularly horizontal boring, drilling and milling machines
IPC: B23B39/02
Filed: 1947-07-30
Abstract: 642,918. Claw clutches; change-speed control. GIDDINGS & LEWIS MACHINE TOOL CO. July 30, 1947, No. 20629. Convention date, Feb. 26, 1940. [Class 80(ii)] [Also in Groups XXII and XXXVII] A clutch which is provided in the feed mechanism of the tool spindles of a horizontal boring, drilling and milling machine (see Group XXII) is arranged so that it may be set to provide for the automatic disengagement of the drive at the end of a pre-determined feed distance. The clutch comprises a disc 212, Fig. 7, which is driven by worm gearing 210, 211 and loosely journalled on a shaft 214. A drum 215 which is rotatable with the shaft 214 is fitted with a number of radially-movable blocks 216 adapted to be moved outwardly against yielding means so that teeth on the outer ends of the blocks engage a toothed annulus on the disc 212. The blocks ;are -moved outwardly by the inward, movement of a plunger 225 which has 'rack 224 engaged by toothed sections 223 on four handles 217 pivoted on a dial plate 221 on drum 215. One of the sections 223 has a cam 227 for connection with a stop pin 228 on a fixed dial ring 222 so that by rotation of the dial-plate 221, the cam 227 may be set in such an angular relation to the pin 228 that disengagement of the clutch by interengagement between the cam and pin occurs after the selected interval; or the dial plate 221 may be rotated to position the pin 228 beyond the maximum range of travel of the' cam 227. The drive to the clutch also includes a nine-speed gear unit 176, Fig. 8, comprising two clutch sleeves 182, 185 operable by a handle 186 to set the gearing to the desired speed. The sleeve 182 is actuated by a shoe 189 slidable on guide rods 189a and the shoe 190 is slidable on rods 190a to operate the sleeve 185. The shoe 189 is engaged by an eccentric pin 196, Figs. 18 and 19, on a mutilated pinion 195 which is driven through gearing 192, 193 from the handle 186; during one revolution of the pin 196, which corresponds to three revolutions of the handle 186, the shoe 189 takes up three successive positions A, B, C, Fig. 19, corresponding to different speed settings of the unit. The sleeve 185 is actuated in timed relation with the sleeve 182 by a second pinion 198 which is loosely journalled on a shaft 199 and meshes with the mutilated gear 195; this gear has teeth extending over a sector of 120 degrees and the teeth of the gear 195 are arrayed in three sectors separated by smooth portions 198a. An eccentric pin 265 on the gear 198 engages a slot 266 in the shoe 190 whereby the latter can be moved to any of its three speed settings D, E, F. In series with the nine-speed unit is a two-speed gear unit, the clutch sleeve of which may be set by a handle 187, Fig. 20, to provide either of the two speeds. Indicating mechanism for showing the speed setting of the combined unit comprises a dial 267, Fig. 20, fixed on the shaft 199 and adapted to be driven from the handle 186 through gearing whereby one revolution of the latter rotates the dial through one-ninth of a revolution. The dial, which is provided with nine pairs of indicia showing the available speed settings, co-operates with a pointer 290 carried on a slide 290a adapted to be shifted axially by the handle 187; the pointer is thereby moved to co-operate with either of the two sets of indications on the dial according to the speed settings of the two-speed unit.