US Patent 7179183 Pulley for a continuously-variable-ratio drive

A pulley for a continuously-variable-ratio drive, having a fixed half-pulley fitted to a shaft of the drive; a movable half-pulley mounted to slide axially with respect to the fixed half-pulley to define with it a V groove of variable size for a V belt; and a torque-sensitive, axial thrust compensating device having an acceleration cam and a deceleration cam, which are interposed between the fixed half-pulley and the movable half-pulley to generate thrust on the movable half-pulley in the compression direction of the belt in response to both a drive torque and a braking torque.