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:
Sep. 08, 1992
Filed:
Apr. 28, 1989
Dino Scanderbeg, Laguna Niguel, CA (US);
William D Wilkerson, Newport Beach, CA (US);
Richard L Kenyon, Irvine, CA (US);
Michael E Nolan, Costa Mesa, CA (US);
Parker Hannifin Corporation, Cleveland, OH (US);
Abstract
An electro-hydraulic actuator having an electric motor disposed in a hydraulic fluid reservoir and connected to drive a hydraulic fluid pump. The actuator includes a piston rod which extends or retracts as a piston is hydraulically driven in a cylinder. An actuator housing forms the reservoir and cylinder and contains hydraulic passages connecting the pump, reservoir and cylinder. The actuator includes a one-way filter for filtering the hydraulic fluid. The hydraulic pump is preferably a rotating piston type and includes a port plate which allows the pump to drive the piston while the retract and extend chambers of the pump have different or unbalanced fluid drive ratios. A load limiting valve protects the system from excessive hydraulic pressure and a position sensor detects the position of the piston rod.