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:
Aug. 17, 1982
Filed:
Sep. 17, 1979
Arthur E Hirsch, Terre Haute, IN (US);
J. I. Case Company, Racine, WI (US);
Abstract
A hydraulic actuator and control for positioning the boom of a backhoe mounted on the rear of a tractor that smoothly decelerates the boom at the limits of its horizontal swinging movement. A directional control valve ports fluid to two double acting hydraulic actuators positioned in opposed relation on the tractor to drive the boom from side to side. The boom is cushioned at the limits of its travel, whether or not the operator releases the operating pedal for the directional control valve, by blocking discharge flow from a contracting actuator to the directional control valve and porting this discharge flow over a pressure relief system that is independent of the directional control valve. The pressure relief system provides substantially constant deceleration of the boom without high peak pressure in the actuator by using a lower pressure relief valve in the actuator cylinder heads arranged in series with a higher pressure relief valve that discharges directly to tank. The higher pressure relief valve also cushions the boom during mid-stroke stopping by an interconnection with the main fluid lines between the directional control valves and the actuators.