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:
Nov. 23, 1993
Filed:
Feb. 12, 1993
J Otto Byers, Jr, Kalamazoo, MI (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
A force motor having a cylindrical armature of ferromagnetic material is provided. An electromagnetic coil is disposed coaxially around the armature. First and second cylindrical plates are disposed on opposite ends of the armature in spaced proximity from the armature forming a respective gap having a predetermined length. A substantially tubular permanent magnet is disposed coaxially around the armature. The magnet is magnetized radially with respect to the longitudinal axis and provides a pair of oppositely directed magnetic flux paths. A current source energizes the electromagnetic coil, which produces an electromagnetic flux path directed through the gaps and the armature to cause the armature to move. Advantageously, temperature compensators are provided to differentially expand and contract, with respect to the cylindrical plates, in response to a varying temperature of the force motor. The differential expansion of the temperature compensators urges the cylindrical plates toward one another to reduce the predetermined length of the gaps.