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. 13, 1990
Filed:
Nov. 05, 1987
Endre A Meyer, Birmingham, MI (US);
Robert D Kachman, Troy, MI (US);
Schenck Pegasus Corporation, Troy, MI (US);
Abstract
Electrohydraulic servovalve structure and method. The servovalve structure has minimum oil passage length and oil volume and a high response force motor with a light weight armature and a stiff flexible tube and includes a second stage pilot valve having an axially movable metering spool therein and a non contacting, electromagnetic, proximity type sensor positioned adjacent one end of the spool for converting axial spool position to an electrical signal. In modifications, a quartz or ceramic window is placed between the one end of the spool and sensor and electronics are placed on the servovalve adjacent the sensor for providing a low impedance spool position output signal from the servovalve. In accordance with the method of the invention, the axial position of the spool is sensed by the eddy current sensor and an electrical signal is provided representative of the position of the spool for use in controlling the electrohydraulic servovalve. In a modification, the position representative signal is converted to a low impedance signal at the servovalve.