Abstract

A self-adjusting mechanism compensates for wear of over-center clutches and the like and is adapted to mechanically sense clutch wear or slack when the clutch is engaged and to compensate for such wear or slack upon disengagement of the clutch. The self-adjusting mechanism preferably comprises a relatively durable and simple ratchet mechanism including teeth mounted on the adjusting ring and a pawl mounted on the clutch face plate. The pawl retracts upon clutch engagement by an amount determined by the thickness of the gap between the adjusting ring and the face plate which is in turn dependent at least in part on clutch wear, and advances upon clutch disengagement by an equal amount. Slack adjustment takes place when the pawl engages a new tooth upon retraction and then advances upon clutch disengagement to drive the tooth and thus the adjusting ring to rotate on the hub. The maximum stroke of the pawl, and thus the minimum adjusted gap between the adjusting ring and the face plate and the maximum torque transmitting capacity of the clutch, can be set by varying the effective length of the lever assembly supporting the pawl.