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. 11, 1992
Filed:
Mar. 16, 1990
Kazuyoshi Arii, Osaka, JP;
Masaru Kumatani, Osaka, JP;
Kubota, Ltd., Osaka, JP;
Abstract
A hydraulic circuit, for use with i.e. a backhoe implement of a work vehicle. The circuit includes an engine, first through third pumps driven by the engine and a plurality of actuators. The invention is characterized by a relief pressure switchover device for selectively providing a first mode for realizing a low relief pressure in the first and second feed oil passages and a second mode for realizing a high relief pressure in the same and a relief pressure control device for causing the relief pressure switchover device to automatically provide the first mode when the third pump is loaded and causing the switchover device to automatically provide the second mode when the third pump is unloaded.