Bidirectional retaining clutch

Abstract

A bidirectional retaining clutch capable of stopping rotation of a rotated object such as a revolving shaft of a pivoted cover of a personal computer, a door sheave of a sliding door or the like in one direction at any desired position while keeping it freely rotatable, as well as ensuring free rotation of the rotated object in an opposite direction as desired when torque of a predetermined level or more is applied. An outer cylindrical structure arranged so as to rotated relative to a shaft includes a pair of roller positioning members each provided on an inner surface with roller receiving recesses of an elliptic shape. The rollers which are received in the recesses selectively move in the recesses so as to permit the shaft to be revolved relative to the outer cylindrical structure in one direction while preventing revolution of the shaft in an opposite direction. When torque of a predetermined level or more in the opposite direction is applied to the shaft, the rollers move in the recesses again to permit it to be rotated in the opposite direction.