US Patent 7108116 Clutch actuator

A clutch actuating apparatus for engaging a clutch on an engine, such as an engine that drives an oil or gas well pump. The clutch actuator includes a first prime mover for rotating a clutch operating shaft in one direction toward a clutch-engaging position, but which unseats from driving the shaft after the shaft reaches the break over point and before engaging the clutch to prevent clutch damage. A second prime mover rotates the clutch operating shaft in the opposite direction toward a clutch-disengaging position, and unseats from driving the shaft after the break over point.