GB766821A - Indexing device - Google Patents

Abstract

766,821. Metal-cutting machine details. CAPLIN, S. R. April 22, 1955 [April 21, 1954], No. 11532/54. Class 83 (3). [Also in Group XXIII] The cross-slide of a cutting or grinding. machine is traversed through a pre-set distance by the swinging movement of an operating lever 6 which co-operates with a ratchet-wheel 4 on the operating-shaft (e.g. the lead screw), of the cross-slide, by means of latches 22, 23, Fig. 5, engaging the ratchet-wheel to lock the lever to the latter against'relative movement in both directions, and when released allowing free movement of the lever relative to the ratchetwheel, rotation of the ratchet-wheel being restricted to one direction only. The lever can swing about the axis of the ratchet within limits determined by stops 8, 11 carried by a fixed plate 9, stop 11 being adjustable in an arcuate slot 12. The latches 22, 23 are pivoted spring- pressed pawls engaging opposite sides of the teeth of the ratchet. The pawl 22 has a fingergrip 28 to disengage it from the ratchet, and when so operated it disengages the pawl 23 also by inter-engaging formations 32 on the two pawls. The latches are held in this disengaged position by a spring-pressed latch 37 which, when the lever 6 is swung into contact with the stop 11, engages the latter to release the pawls for engagement with the ratchet. A spring- pressed withdrawable pawl 15 carried by the stop 8 prevents movement of the ratchet except in the direction from stop 11 to stop 8. Operation. The adjustable stop 11 is set to the position corresponding to the required amount of feed by movement of the lever between the two stops, the pawl 15 is engaged, and, with the lever abutting the stop 8, the pawls 22, 23 are disengaged by finger 28 and the lever then swung until it contacts the stop 11. The latch 37 then automatically releases the pawls for engagement with the ratchet and movement of the lever in the reverse direction rotates the ratchet through the required arc of feed.