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:
May. 02, 1989
Filed:
Jul. 02, 1987
Applicant:
Inventor:
Shih Y Sheng, Santa Anna, CA (US);
Assignee:
Parker-Hannifin Corporation, Cleveland, OH (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F01B / ; F15B / ; F15B / ;
U.S. Cl.
CPC ...
91171 ; 91510 ; 91515 ; 91517 ; 91518 ; 91528 ; 91530 ;
Abstract
A system reduces force fight between hydraulic actuators (22, 24) operated on independent hydraulic circuits (29, 49) which position a control surface (20) of an aircraft. Each circuit includes a hydraulic supply (30, 50). A pressure equalization valve (70) is connected to first sides (42, 62) of the actuators. In the event of a pressure imbalance, a spool (82) shifts in the pressure equalization valve. Movement of the spool enables fluid from the circuit supply to be delivered through the equalization valve to the actuator at the lower pressure, rapidly eliminating the imbalance.