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:
Dec. 15, 1998
Filed:
Jan. 03, 1997
Tsuyoshi Nakamura, Ibaraki-ken, JP;
Toichi Hirata, Ushiku, JP;
Genroku Sugiyama, Ibaraki-ken, JP;
Tsukasa Toyooka, Ibaraki-ken, JP;
Youichi Kowatari, Ibaraki-ken, JP;
Kouji Ishikawa, Tsuchiura, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A hydraulic system for a construction machine includes a hydraulic pump driven by a prime mover, actuators driven by a hydraulic fluid delivered from the hydraulic pump, flow control valves for controlling flow of the hydraulic fluid to the actuators and operation means for operating the flow control valves. A relief value sets a relief pressure for limiting the maximum delivery pressure of the hydraulic pump and relief pressure change means increase or decrease the relief pressure set by the relief valve. The relief pressure change means automatically increase or decrease the relief pressure in accordance with the input amount of the operation means.