GB422069A - Improvements in machines for lapping or burnishing the profiles of gear teeth and screw and worm threads - Google Patents

Abstract

422,069. Lapping gears, screws, &c. BROWN & SONS (HUDDERSFIELD), Ltd., D., and MERRITT, H. E., Park Gear Works, Lockwood, Huddersfield. Aug. 18, 1933, No. 23048. [Class 60] In a machine for lapping gear teeth, screw or worm threads, &c., and in which the gear, &c., is rotated in contact with a lap having the form of a conjugate gear, &c., and is at the same time reciprocated, the workpiece c, shown as a worm, is mounted between centres d, e, on a table b, the centre d being directly driven by an electric motor f on the table. The motor also drives, through gearing g, h, h<1>, a shaft i carrying a disc il having in a slot i<2> therein, an adjustable crank-pin carrying a roller i<4>, which engages a slot j in a member j<1> adjustable on the machine bed a by a screw j<2> ; rotation of the motor thus drives the worm c and, through the crank mechanism, reciprocates the table b. The motor f is reversed after a predetermined number of reciprocations of the table by means of a switch t<2> operated by a pin t on the switch lever t<1>, the pin being engaged by a. collar s<4> on an axially movable sleeve s<2>, which carries pairs of differently spaced projections s, s<1> engaged by a projection r on a nut p<1> moved in a fixed guide p<3> by a screw p driven by gearing o, d from the shaft i. The sleeve s<2> is rotatable, to bring the required pair of projections s, s<1> into operative position, by a spindle s<3>, and at the end of the reversed stroke of the sleeve s<2>, the switch is opened and the motor f stopped. The worm c engages a lapping-wheel u carried on a spindle mounted in antifriction bearings in a head u<4> and geared to a rotary gear pump which serves to brake the movement of the wheel u, the pump having a relief valve v<1> whereby the braking torque may be adjusted as indicated by a pressure gauge v<2>. Abrading-compound is supplied to the work by a pump which is started and stopped automatically when the motor f is started and stopped. In operation, the work rotates and makes a predetermined number of reciprocations, as determined by the pair of stops s, s<1> in operation, the motor then being reversed whereby the work rotation is reversed, and, after the same number of reciprocations of the work the motor is stopped.