1. In a motor having an output shaft, a rotor secured to the output shaft, at least one stator mounted concentric with the rotary axis of said output shaft, means for restricting rotation of said stator, and means for coupling the rotor and stator for rotating the rotor and thus driving the output shaft, a torque sensing device comprising means coupled to said stator rotation restricting means for sensing a reaction torque in said stator over a predetermined amount and first and second switch means coupled to said sensing means for performing a control function, said means for restricting rotation of said stator including a stationary member, a movable member pivotally secured to said stationary member, and first and second switch actuating members on said movable member and operable upon pivoting of said movable member in opposite directions due to oppositely directed increases in reaction torque to actuate said first and second switch means, respectively.

3. In a nutating type motor having an output shaft, a rotor secured to the output shaft, at least one stator mounted concentric with the rotary axis of said output shaft, means for restricting rotation of said stator, and means for nutatively driving the output shaft, a torque sensing device comprising means coupled to said stator rotation restricting means for sensing a reaction torque in said stator over a predetermined amount and means coupled to said sensing means for performing a control function, said stator being a swashing member, said means for restricting rotation of said stator including a force transferring member, said sensing means including spring-biased stop means engageable with said force transferring member and being movable upon the reaction torque in said stator exceeding the spring bias, switch means for opening an electrical circuit, and switch actuator means coupled to said stop means for actuating said switch means.

5. In a nutating type motor having an output shaft, a rotor secured to the output shaft, at least one stator mounted concentric with the rotary axis of said output shaft, means for restricting rotation of said stator, and means for nutatively driving the outpUt shaft, a torque sensing device comprising means coupled to said stator rotation restricting means for sensing a reaction torque in said stator over a predetermined amount and means coupled to said sensing means for performing a control function, said motor including two stators engaging said rotor on opposite sides thereof, said stator rotation restricting means including a pair of bearings allowing free swashing movement of the stators, spring-biased means for holding the bearings against movement about said shaft axis until a predetermined reaction torque is exceeded by said stators and then moving with said bearings a limited amount, said means for performing a control function including switch actuator means movable with said spring-biased means, and switch means operated by said switch actuator means for operating an electrical circuit.

7. A torque limiting device for a valve actuator having a valve closing member driven by a nutative-type electrical motor having an output shaft, a rotor coupled to said motor output shaft, and at least one stator nutatively driving said rotor, said device comprising stator rotation limiting means, means yieldably mounting said stator rotation limiting means for allowing limited rotational movement in response to the reaction torque in said stator exceeding a predetermined amount, and means responsive to said limited stator rotation for de-energizing said motor to stop movement of said valve closing member, said yieldable mounting means including a fixed limit plate, a movable rocker arm pivotally mounted on said limit plate, yieldable plunger means abutting between said limit plate and said rocker arm, said yieldable mounting means including spring means in said plunger means to allow pivotal movement of said rocker arm, switch means for de-energizing the motor, and means on said rocker arm for actuating said switch means in response to pivotal movement of said rocker arm.