GB674656A - Improvements in or relating to screw-cutting lathes - Google Patents

Abstract

674,656. Screw-cutting lathes. MASCHINENFABRIK HEID AKT.-GES. Feb. 14, 1950 [March 2, 1949], No. 3726/50. Class 83 (iii). A lathe having a lead-screw and a feed shaft driven from the headstock spindle, the feed shaft driving a pinion which co-operates with a rack on the lathe bed, is characterized in that an additional gear train is interposed in the gear drive connecting the headstock spindle to the pinion to enable the saddle to be fed at the same rate of feed by the feed shaft as by the lead-screw. The feed shaft drives through bevel gears 2 a worm and worm wheel 3, 4, carried by the saddle. This drive may be connected to the cross-traverse screw by sliding a pinion 5 on the shaft of the bevel wheel into mesh with a pinion 16. The pinion 5 when disengaged from the cross-traverse train may be engaged with a wheel 6, Fig. 2, and a pinion 7, secured to the same shaft as this wheel, may then be engaged to drive the rack pinion 9 for the saddle feed movements by sliding the wheel block 8, 14, to engage gears 7 and 8. When the wheel block is moved in the opposite direction, wheel 14 engages a wheel 13 forming a block with wheel 12, the latter is driven by a wheel 11, also on the worm wheel shaft, and the saddle is thus fed at the same rate as that given by the lead-screw, thus enabling the feed shaft to be used for the initial roughing cuts of a screw-cutting operation.