GB933441A - Improvements in and relating to epicyclic friction gearing - Google Patents

Abstract

933,441. Control of motors. GEORGE ANGUS & CO. Ltd. Nov. 3, 1959 [Nov. 3, 1958], No. 35192/58. Class 38 (3). [Also in Group XXIV] In an epicyclic friction gearing wherein rolling elements 6 in a driven (or driving) cage 7 engage a stationary outer race and a driving (or driven) inner race 1, the outer race comprises two parts, one, 4a, which is fast in a casing 5 and another, 4b, which is urged to contact the rolling elements 6 by a spring 11 the loading of which and hence the torque transmitting characteristics of the gear are controlled by an axially movable thrust ring 12. As shown, the ring 12 may be axially moved by circumferential movement of an extension 14 of one of two diametrically opposed radial pins screwed in the ring and engaging helical slots 16, 17 in the casing 5, the end positions of the pins corresponding to zero and maximum torque transmission. The extension 14 may be operated directly or remotely, e.g. through linkage. Positioning means (not shown) for the extension 14 may comprise a gate or notches in the slot 16 in which the extension may be retained by pressure of the spring 11, or means operating on the remote control. In Fig. 3 (not shown), the ring 12 may be controlled by a fork fulcrumed on the casing 5 and engaging diametrically opposed radial pins extending through axial slots in the casing. The rolling elements may be cylindrical, tapered, barrel or other shaped rollers, or, as shown, balls. The device may be provided to stop a driving electric motor when predetermined slip in the gear is established. Such a device may comprise a temperature-responsive device such as a bi-metallic strip disposed near the rolling drive transmitting part of the gear to be responsive to temperature rise due to slipping friction and arranged to actuate a switch, or a combination known as a thermal switch. The gear so equipped may be used for driving a mechanism, e.g. a motorized valve in a chemical plant, to a stop position after which the drive slips, heat is generated and the switch actuated to stop the drive. Specification 893,861 is referred to.