Electromechanical actuator

Claim 1

AN ELECTROMECHANICAL ACTUATOR, COMPRISING: A SOLENOIDAL COIL ADAPTED TO BE INTERMITTENTLY ENERGIZED BY CURRENT IMPULSES OF GIVEN POLARITY; AN ARMATURE MOUNTED FOR LIMITED LENGTHWISE TRAVEL THROUGH THE HOLE IN THE COIL; A TORROIDAL PERMANENT MAGNET MAGNETIZED IN THE AXIAL DIRECTION AND MOUNTED TO COAXIALLY SURROUND THE COIL; TWO MAGNETICALLY CONDUCTIVE POLE MEMBERS MOUNTED TO EACH SUBSTANTIALLY COVER A RESPECTIVE END OF THE COIL AND MAGNET AS ASSEMBLED, SAID POLE MEMBERS EACH PROVIDING AN AXIALLY LOCATED OPENING ADAPTED TO ADMIT A RESPECTIVE END OF THE ARMATURE AT A RESPECTIVE TERMINUS OF THE PERMITTED TRAVEL THEREOF, THEREBY DEFINING A VARIABLE-RELUCTANCE AIR GAP BETWEEN EACH END OF SAID ARMATURE AND A RESPECTIVE POLE MEMBER; MEANS FOR MAGNETICALLY SHUNTING ONE OR THE OTHER OF THE VARIABLE RELUCTANCE GAPS, SAID MEANS COMPRISING AN AUXILIARY ARMATURE AT LEAST PARTIALLY CONSTRUCTED OF MAGNETIC MATERIAL AND MOUNTED TO BE MOVABLE RECIPROCATIVELY BETWEEN TWO RELATIVE OPERATIONAL POSITIONS IN EACH OF WHICH IT PROVIDES A SUPPLEMENTAL FLUX PATH BETWEEN ARMATURE AND POLE MEMBER AND IS THEREBY MAGNETICALLY HELD IN POSITION BY VIRTUE OF THE MAGNETOMOTIVE FORCE GENERATED BY THE PERMANENT MAGNET EXCEPT AT SUCH TIMES AS THE COIL IS APPROPRIATELY ENERGIZED TO PRODUCE A COUNTERACTING MAGNETOMOTIVE FORCE;