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. 14, 1979
Filed:
Mar. 27, 1978
Donald J Parquet, Burlington, IA (US);
J. I. Case Company, Racine, WI (US);
Abstract
A hydraulic pump unloading system having an engine driving two hydraulic pumps which are connected in parallel to a load-supporting member. An unloading valve is connected in the hydraulic line with one of the two pumps and is shiftable between positions for directing flow to the load and for directing flow to a reservoir, depending upon the pressure and or flow in the hydraulic line. Also, a pressure-compensated flow-control valve is connected in the line with the other pump and, under certain conditions, directs fluid pressure to the unloading valve for setting the unloading valve in either the operative or the unloading position, all depending upon the hydraulic condition at the load-supporting member. Further, either an additional valve or a spring can be effective on the unloading valve for controlling the operative and the unloading position of the unloading valve. The system is arranged so that when the workload approaches an excessive magnitude, one of the pumps is unloaded so that the engine will not stall.