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. 01, 2005
Filed:
Oct. 01, 2003
Mark J. Jervis, Liverpool, GB;
Robert J. Valenta, Chester, GB;
Lynn A. Russell, Eagle, WI (US);
Sean M. Haggerty, Waukesha, WI (US);
Mark J. Jervis, Liverpool, GB;
Robert J. Valenta, Chester, GB;
Lynn A. Russell, Eagle, WI (US);
Sean M. Haggerty, Waukesha, WI (US);
HUSCO International, Inc., Waukesha, WI (US);
Abstract
A member that is driven by a hydraulic actuator tends oscillate when fluid flow to the hydraulic actuator is terminated. A pressure relief device reduces that oscillation by connecting first and second first relief valves to the hydraulic actuator. The first relief valve provides a relatively large first relief passage as long as pressure in the hydraulic actuator remains above a threshold. A second relief valve opens a second relief passage at substantially the same threshold pressure and thereafter remains open as long as the pressure remains above another lower threshold. A timer causes the second relief valve to close a given interval of time, if the pressure does not drop below the other lower threshold.