Abstract: A mounting plate assembly has provisions for reducing the motor noise transmission from a DC stepper motor or the like that has an associated reducing gear assembly. The mounting plate assembly is formed of a front plate which provides the bushings for the shafts of the reducing gears and on which an output bearing is mounted for journalling an output shaft. A generally discoid inner mounting plate of a first diameter is affixed adjacent the front plate and serves as a mount for holding the retaining cup or the overall stepper motor and gear assembly. An outer mounting plate, which has a second diameter smaller than the first diameter, serves for mounting the overall assembly in place, and has an aperture, favorably provided with a sleeve, coaxial with the output bearing. In order to provide acoustic isolation, a layer of resilient rubber is vulcanized in place between the inner and outer mounting plates. A portion of the gasket fills the annulus between the output bearing and the sleeve.

Abstract: A linear stepper motor is provided with a feature to cause it to return to a zero position when current is cut off. The motor is formed of a stator armature assembly and a permanent magnet rotor assembly with poles thereof facing poles of the stator armature. The rotor assembly includes a rotor core formed as a nut with an axial threaded aperture extending therethrough. A shaft assembly includes a shaft screw mating with the rotor core nut, a front shaft affixed thereto, and a fixed sleeve overfitting the front shaft to permit axial motion thereof. A ball-and-groove arrangement in the front shaft and the sleeve prevents rotation of the shaft without impairing axial movement thereof. A spring causes return of the shaft to zero when there is no current applied to the stator armature. The spring can, for example, be a coil compression spring overfitting a portion of the shaft or a spiral torsion spring extending between the rotor and the stator armature.

Abstract: An electric motor having a stator with a plurality of pole pieces which are disposed in angularly spaced intervals about the axis of rotation of a cooperating rotor. Each stator pole piece has one or more teeth thereon. Each tooth has an inner peripheral surface which lies on the circumference of a circle having its center on the axis of rotation of the rotor. The teeth on each stator pole piece (which has a plurality of teeth) are spaced with a uniform pitch therebetween and the pitch on one stator pole piece is the same as the pitch on any other stator pole piece. One of the stator pole pieces and an adjacent stator pole piece about the axis of the rotor comprise a pole pair. Each two successive stator pole pieces disposed about the axis of the rotor comprise additional pole pairs.