GB664477A - Improvements in automatic reversing arrangements for electric motors - Google Patents

Abstract

664,477. Control of motors; controllers. NORTON & CO., Ltd., Sir J. F. Sept. 20, 1950. [Sept. 29, 1949] No. 24995/49. Class 38 (iii). An arrangement for providing an adjustable period of operation for an electric motor before reversal comprises a motor-driven worm a engaging a two-part worm wheel b, c, which separately drives through friction clutches discs f, h, of insulating material. Electric contacts in a circuit for reversing the motor are adapted to engage contacts on the peripheries of both discs when the discs are in definite relative positions the teeth on the two parts b, c, being of slightly different pitch so that the discs are driven at different speeds. The disc f is secured to shaft i, which is fixed to a part f in frictional driving engagement with the member b. A handle k allows for aerial movement of the shaft to release the frictional engagement between parts f, b, and turning of the handle sets the disc f in its desired initial position. A handle r turns arm 8 to displace disc h and sleeve g axially and rebases the frictional pressure between the parts g and c. The disc h is then positioned by movement of the handle m which turns, through gearing n, o, p, a gear wheel q secured to the disc. Operation of the handles k and m thus determines the number of revolutions of the worm wheel a which occur before the motor is reversed.