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. 06, 1986
Filed:
Nov. 19, 1984
Lawrence F Schexnayder, Joliet, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
Hydraulic motors are conventionally employed in rotating the upper structure of excavators and the like. Protection from inertia induced hydraulic shock loads of some hydraulic control circuits involves the use of a separate bypass valve which continuously interconnects the motor conduits. The subject control circuit includes a pair of shunt valves each of which establishes restricted communication between the first and second motor conduits in a particular direction at their normal spring biased position. This allows limited free swing of the upper structure when the directional control valve is shifted from an operating position to the neutral position. However, shifting the directional control valve to an operating position causes the appropriate one of the shunt valves to shift to a blocking position so that no interconnection between the motor conduits exist. Thus, the disclosed control circuit causes all pressurized fluid directed into one of the motor conduits to be transmitted to the hydraulic motor for maximum efficiency.