Patent ID: 7190096

Claim:
An electrically-powered linear actuator comprising: an output ram (hereafter the “output ram”) having a central axis and an exterior threaded surface; a housing having a first opening through which the output ram extends and retracts; a first electric motor (hereafter the “first motor’) fixed in said housing, said first motor providing a first stator and a first armature within the stator that rotates about the axis of the output ram, said first armature being carried in a manner to prevent its axial movement along the output ram axis while permitting its rotation about the output ram axis, the first armature's rotation causing the output ram to retract into or extend from the housing when the first armature is engaged with the output ram's threaded surface; a second electric motor (hereafter the “second motor”) fixed in said housing and adjacent the first electric motor, said second motor providing a second stator around the output ram and a second armature within the second stator that rotates about the axis of the output ram, said second armature being carried in a maimer to prevent its axial movement along the output ram axis while permitting its rotation about the output ram axis, the second armature's rotation causing the output ram to retract into or extend from the housing when the second armature is engaged with the output ram's threaded surface; and an armature releasing mechanism, operatively coupled to at least one of the first armature and the second armature to decouple the corresponding armature from the output ram upon the existence of a fault.