GB376750A - Improvements in lapping machine - Google Patents

Abstract

376,750. Grinding. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.-(Pratt & Whitney Co. ; Hartford, Connecticut, U.S.A.) April 13, 1931, No. 10881. [Class 60.] Rollers, spindles, and the like, treating.- A machine for lapping conical members of antifriction bearings &c. consists of three laps of part conical form rotating at different speeds and engaging the surface of the work at angularly spaced positions, the differences in the speeds of the laps causing the work to rotate at an intermediate speed. The machine comprises a base 10 having on its upper surface movable heads 11 supported by parallel links 13 carried by shafts 14, 15 in housings 12, so that the head may move towards and from the work W. Within the heads 11 and carried thereby, are electric motors 34 which drive through gearing, shafts 16, each carrying a cast-iron &c. lap 17 of frusto-conical form to which abrasive is applied. The work W is carried, so as to be capable of adjusting itself laterally, by a vertical shaft 18 rotatably mounted in a sleeve 19 movable axially to give the work a slight axial reciprocation by a lever 21 and a cam 23, the sleeve being supported by a spring 20, the tension of which is adjustable by a wheel 92 operated, through worm gearing, by a shaft 95 and hand-wheel 96. During lapping, the laps rest upon the work with a pressure due to the weight of the heads 11, and the heads are moved simultaneously away from and towards the work by the vertical movements of a rod 25 carrying lugs 26, 27 adapted to engage a pin on a bevel gear 24 on one of the shafts 14, which are geared together by other bevel gears 24 ; the lugs are separated so that they are free of the pin when the laps engage the work, by a lever 29, which lifts the lug 27 against the pressure of a spring 33. The rod 25 is lifted by a cam 80 carried by a shaft 52 which is driven at two different speeds from the shaft 36 of a motor 35, one speed being a direct drive through gearing 37, 40, 43, 45, bevel gears 46 carried freely in a yoke 47 on a worm wheel 41 and gearing 50, 51, and the second, and increased, speed being obtained by clutching a worm 38 to the shaft 36 and releasing a brake from the sleeve of the worm 38, whereby the wheel 41 rotates in the opposite direction to the wheel 40. The clutch and the brake are operated by a lever 72 actuated by dogs 75 on a disc 76 on the shaft 52. The work is removed and replaced by another work-piece during the period of increased speed of the shaft 52, and operation on a work-piece is completed in one rotation of the cam 80.