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:
Mar. 12, 1996
Filed:
Jun. 27, 1994
George Codina, North Hollywood, CA (US);
Eldon D Oestmann, Morton, IL (US);
Gary J Shane, Edelstein, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
An apparatus for determining the spool position of a directional valve is disclosed. A longitudinal valve housing has opposed ends and a plurality of fluid ports, and a spool moves reciprocatingly within the valve housing. A first spring disposed adjacent an end of the spool extends and retracts with the reciprocating movement of the spool. A first oscillator circuit is coupled to the first spring and is adapted to produce a first position signal in response to the inductance of the first spring. Finally, a logic device determines the incremental linear position of the spool relative to the housing in response to the frequency of the first position signal.