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:
Feb. 10, 2009
Filed:
Nov. 01, 2002
Tsuyoshi Nakamura, Niihari-gun, JP;
Tsukasa Toyooka, Higashiibaraki-gun, JP;
Koji Ishikawa, Niihari-gun, JP;
Masao Nishimura, Niihari-gun, JP;
Tsuyoshi Nakamura, Niihari-gun, JP;
Tsukasa Toyooka, Higashiibaraki-gun, JP;
Koji Ishikawa, Niihari-gun, JP;
Masao Nishimura, Niihari-gun, JP;
Hitahi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
To permit smooth performance of both of an operation requiring a high pressure and an operation desired to produce a pressure at a suppressed level, a shuttle block positioned between pilot operating units and flow control valves and pump regulators is arranged in association with shuttle valves, which select maximum pressures of groups of operation signal pressures produced by the pilot operating units, respectively, and at least one of the plural groups of operation signals, and is constructed to include hydraulic selector valves and a boom-lowering, hydraulic selector valve that are operable in particular ways.