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. 25, 2003
Filed:
Dec. 20, 2001
Kiwamu Takahashi, Shiga-ken, JP;
Takashi Kanai, Kashiwa, JP;
Yasutaka Tsuruga, Moriyama, JP;
Kenichiro Nakatani, Shiga-ken, JP;
Junya Kawamoto, Moriyama, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
Differential pressures across flow control valves and are controlled by pressure compensating valves and to be held at the same value, i.e., a differential pressure &Dgr;PLS, and the differential pressure &Dgr;PLS is maintained at a target differential pressure &Dgr;PLSref by a pump displacement control unit . For changing the target differential pressure depending on change in revolution speed of an engine , a flow detecting valve is disposed in a delivery line of a fixed displacement hydraulic pump , and a differential pressure &Dgr;Pp across a variable throttle portion of the flow detecting valve is introduced to a setting controller . A selector valve operable to shift between a fully closed position and a throttle position is disposed in parallel to the flow detecting valve and is shifted by a control lever