US Patent 7984894 Electrical clutch engagement/disengagement apparatus

A clutch operable with equipment, including a winch of the type having a planetary gear reduction assembly for driving a cable drum. The planetary gear assembly includes a ring gear which, when allowed to rotate, effectively disconnects the drive motor from the cable drum. When the ring gear is fixed against rotation, the drive motor can drive the cable drum to wind or unwind the cable therefrom. A bistable solenoid is employed so that a plunger thereof is engageable with the ring gear to either allow rotation or prevent rotation, and thus engage or disengage the clutch. The bistable solenoid does not require electrical power when the plunger is in either stable position, thereby conserving electrical energy.