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. 21, 1989
Filed:
Jul. 26, 1988
Thomas Q Haeder, Lisbon, ND (US);
William C Shelbourn, Bismarck, ND (US);
Clark Equipment Company, South Bend, IN (US);
Abstract
An auxiliary coupler pressure relief hydraulic system for off-road vehicles including a battery, an engine, an engine ignition system, a reservoir of hydraulic fluid, and a pump for providing hydraulic fluid under pressure. Quick couplers couple hydraulic fluid to an attachment mounted to the vehicle. An electro-hydraulic spool valve is connected to a source of pilot pressure and controls the flow of hydraulic fluid to the quick couplers in response to valve actuating signals. Forward and reverse auxiliary control switches are coupled to the spool valve and provide valve actuating signals resulting in fluid flow to the quick couplers in forward and reverse directions. Also included is an ignition switch having RUN, OFF and RELIEF positions. When switched from its RUN position to its RELIEF position, the ignition switch provides pressure relief valve actuating signals which stroke the spool valve and bleed pressure trapped between the valve and the quick couplers while the engine RPM is decreasing and pilot pressure is still available.