Manual override and locking mechanism and actuator including same

A rotary actuator, comprising a motor (20), a gear train (36), an output coupling (26) driven by the motor (20) through the gear train (36), the gear train multiplying the engine torque, to drive the output coupling the rotary actuator characterized by comprising a manual override mechanism having a first user accessible interface (22), operating the manual override mechanism, in conjunction with the train gear to allow manual positioning of the output coupling, and manual locking mechanism (52) having a second interface accessible by the user (28), the manual locking mechanism engaging the gear train (36) to prevent rotation of the output coupling (26) in a first direction.