GB479701A - Improvements relating to indexing mechanisms - Google Patents

Abstract

479,701. Indexing-mechanism. GEAR GRINDING CO., Ltd., ORCUTT, A. H., and BULLOWS, R. J. Dec. 5, 1936, No. 33430. [Class 83 (iii)] Indexing - mechanism particularly for a spindle a carrying a heavy work-piece comprises a toothed or notched indexing-plate b which is actuated intermittently with slight over-travel by an oscillating pawl e, the plate movement being resisted by a friction brake which is restrained by resilient means whereby energy stored in the resilient means is used after cessation of the pawl movement to impart a slight reverse movement to the plate to move same into correct engagement with an independent positioning - pawl u. The teeth c of the plate have one radial face d. The actuating-pawl e is mounted on an arm f which is connected by a rod i and member m to a crank disc o on an operating- shaft p. When the latter is actuated the pawl e rotates the indexing-disc through slightly more than the desired distance while the positioning-pawl u moving on a stationary pivot rides idly over the rear face of each tooth. A brake drum w on the spindle is engaged by a pair of brake shoes which are adjustably held against the drum by a spring 2. When the indexing-disc is rotated, it tends to carry the brake shoes round with it thereby causing a stop 7 carried by lugs 8 secured to one of the shoes to compress a spring 6 on a rod 5, supported by a bearing member 9. As soon as the pawl e begins its return movement the spring 6 acts on the stop 7 to give a short return movement to the index disc thereby forcing the radial face of the operative tooth against the positioning-pawl u for accurately determining the indexed position. The index disc is adjustable relatively to the spindle by means of screws 21 carried by the part 20 of a retaining member 17 'and coacting with a rod 22 secured to the disc. The brake shoes may be disengaged from the drum when required by means of a rod 11 having a handle 14.