GB919279A - Improved overrunning coupling - Google Patents

Abstract

919,279. Ratchet clutches. FORD MOTOR CO. Ltd. June 23, 1961 [June 24, 1960 (2)], No. 22869/61. Class 80 (2). [Also in Group XXXIV] A unidirectional or bidirectional overrunning clutch or detent comprises one set or two oppositely acting sets of jamming rollers which are engageable and/or releasable by fluid pressure means. In one embodiment rollers 58, 60 are located in cavities 52 in an outer race 48 and are urged together out of engagement with oppositely directed cam surfaces 54, 56 by spring-urged pistons 84, 88. Admitting fluid pressure through a port 64 to the space between the rollers urges the rollers into engagement with the cam surfaces to lock the outer race to an inner race 46, this engagement being aided by a weak spring 62. Pressurizing the space behind piston 84 or 86 releases the associated roller so that overrunning is allowed in the appropriate direction. In a modification the springs acting on the pistons are omitted, the spring 62 thus locking the races in the absence of pressure behind the pistons. In another embodiment having two sets of rollers, these are disposed in separate cavities and the rollers are urged into the engaged position by fluid pressure only, springs equivalent to the springs 62 being omitted. In all embodiments the pistons associated with one set of rollers are rigidly interconnected so that they move simultaneously.