The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 26, 1985
Filed:
Oct. 15, 1981
Charles W Hansen, Wolcott, CT (US);
Haydon Switch & Instrument, Inc., Waterbury, CT (US);
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.