Rotary actuator

A rotary actuator comprising a pair of stators fixedly mounted in spaced opposition to each other having first and second poles lying along a common axis of magnetization an armature comprising a cylindrical permanent magnet having opposed first and second fixed poles of positive and inverse polarity respectively along a diametric polar axis, said armature being mounted between said opposed stators to be reciprocably pivotable about its central axis and with the diametric polar axis generally transverse to the common axis of magnetization of said stators, at least one of said stators comprising an electromagnet having a non-permanent magnetizeable core disposed parallel to the central axis as to provide longitudinally extending first and second stator poles, and a winding parallel to the central axis to provide said first and second stator poles, with opposite polarity, the core of said stator being asymmetrically shaped with respect to the common axis of magnetization to provide a greater force field to one side and a lesser force field on the other side of the common axis of magnetization, and an electric circuit for energizing a selected one of said stators to induce on said first and second stator poles thereof positive and inverse polarity respectively thus causing the selected stator to attract or to repel the fixed pole of said armature magnet on the corresponding side of said greater force field to thereby pivot said armature from one to the other of said stators.

A rotary actuator comprising a cylindrical permanently magnetized armature freely rotatable about its central axis and having fixed poles of opposite polarity lying in a diametric polar axis, an electromagnetic stator and a permanent magnet mounted in opposition to each other adjacent to and along the length of said armature, said electromagnetic stators comprising a core formed of non-permanent magnetizable material disposed parallel to the central axis so as to provide longitudinal edges and a winding arranged about said core to produce poles of opposite polarity on each of longitudinal edges along an axis extending transversely to the length of said core, the core of said electromagnetic stator being asymmetrically shaped so as to produce, when said stator is impressed with a current, an increased flux pattern intersecting one of the armature poles and a decreased flux pattern intersecting the other, said permanent magnet disposed parallel to the central axis so as to provide longitudinal edges having poles of opposite polarity along its longitudinal edges, the polarity along the edge adjacent the armature producing a continuous repelling magnetic flux field on the one pole of said armature located in the corresponding area of the increased magnetic flux field causing said armature to be normally biased toward said electromagnetic stator, means for impressing on said electromagnetic stator an electric current to temporarily produce magnetic poles therein of a selected polarity greater than said continuous magnetic flux field of said permanent magnet to cause counter-repulsion of said armature away from said electromagnetic stator, and means for limiting the rotation of said armature in each of the biased and counter-repelled movements to a fixed position.