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:
Apr. 03, 2007
Filed:
Dec. 27, 2002
Hidetoshi Satake, Ishioka, JP;
Hiroshi Tsukui, Abiko, JP;
Kazuhiro Ichimura, Niihari-gun, JP;
Hiroshi Onoue, Inashiki-gun, JP;
Hidetoshi Satake, Ishioka, JP;
Hiroshi Tsukui, Abiko, JP;
Kazuhiro Ichimura, Niihari-gun, JP;
Hiroshi Onoue, Inashiki-gun, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A hydraulic circuit includes a control valve that controls flow of pressure oil from a hydraulic source to work hydraulic cylinders, an operating device that issues a command for drive of the control valve, valve devices each comprising a check valve, each provided in correspondence to one of the plurality of work hydraulic cylinders to allow and prohibit outflow of pressure oil from a work hydraulic cylinder, a commanding device that outputs a command allowing or a command prohibiting extension/contraction for each of the work hydraulic cylinders and a control device that controls each of the valve devices to allow outflow of pressure oil from the work hydraulic cylinder by invalidating a check valve function in response to the command for allowing extension/contraction and to prohibit outflow of pressure oil from the work hydraulic cylinder with the check valve in response to the command for prohibiting extension/contraction.