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:
Oct. 07, 1980
Filed:
Feb. 26, 1979
Frederick D Ezekiel, Lexington, MA (US);
Alf L Carroll, Jr, Cohasset, MA (US);
The Foxboro Company, Foxboro, MA (US);
Abstract
An electric force motor includes two movable and independently actuatable coils energized by a single magnetic circuit. Air gaps are formed at respective ends of a tubular permanent magnet between a core of magnetically permeable material mounted within the magnet and pole pieces attached to opposite ends of the magnet. Such a configuration thus establishes a serial magnetic circuit connecting the magnet and the core through each of the air gaps. The two coils, each positioned within the respective air gaps, receive independent electrical input signals to develop corresponding output forces. Interactions between each coil that would tend to affect accuracy are minimized by choosing a magnet of high coercivity and by limiting the amount of input current applied to each coil.