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:
Sep. 16, 2003
Filed:
Jul. 19, 2001
Tsukasa Toyooka, Higashiibaraki-gun, JP;
Toichi Hirata, Ushiku, JP;
Genroku Sugiyama, Inashiki-gun, JP;
Kouji Ishikawa, Niihari-gun, JP;
Masao Nishimura, Niihari-gun, JP;
Tsuyoshi Nakamura, Niihari-gun, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
Provided are hydraulic pumps , a control valve group connected to the pump and including a bypass on/off valve , a control valve group connected to the pump and including a reserve-actuator-controlling, directional control valve , a communication line communicating a most upstream side of the control valve group with a supply line to the reserve-actuator-controlling, directional control valve , a merge control valve for communicating or cutting off the communication line , an interlocked control means for changing over the merge control valve to an open position and the bypass on/off valve to a closed position in association with a change-over operation of the reserve-actuator-controlling, directional control valve , and a selective control valve capable of taking one of a state, in which the operation to change over the merge control valve by the interlocked control means is feasible, and another state in which the operation to change over the merge control valve by the interlocked control means is infeasible. The control valve group , the control valve group , the communication line and the merge control valve are arranged in a housing such that a change or the like in a maximum value of an operating speed of an actuator, said operating speed being controlled by the reserve directional control valve, can be achieved.