US Patent 7735581 Locking clutch for downhole motor

A locking clutch to selectively transmit torque from a stator of a downhole tool to a rotor of the downhole tool includes at least one locking pawl disposed upon the rotor. The at least one locking pawl comprises a load path, a pivot axis, and a mass center, and is biased into an engaged position by a biasing mechanism. The at least one locking pawl transmits force from the stator to the rotor along the load path when in the engaged position, and centrifugal force urges the at least one locking pawl into a disengaged position when the rotor is rotated above a disengagement speed.