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. 03, 2013
Filed:
Feb. 04, 2010
Katsuki Yamagata, Akashi, JP;
Katsuki Yamagata, Akashi, JP;
Kobelco Cranes Co., Ltd., Tokyo, JP;
Abstract
Second-gear blocking switching valvestoare provided in pipe lines providing communication between remote control valvesand pilot operation portions of valve sections of second-gear spools of control valves. A switching selection meansswitches the second-gear blocking switching valvesto. Proportional pressure reduction valvestochange secondary pressure to be outputted in accordance with secondary pressure of the remote control valves. Secondary pressure changing switching valvestoare provided in pipe lines providing communication between the remote control valves and pilot operation portions of valve sections of first-gear spools of the control valves. The secondary pressure changing switching valves are switched to first positions for transmitting the secondary pressure of the remote control valves to the pilot operation portions when the second-gear blocking switching valves are switched to transmission positions, and switched to second positions for transmitting the secondary pressure of the proportional pressure reduction valves to the pilot operation portions when the second-gear blocking switching valves are switched to block positions. In the present invention, it is possible to selectively use the one-pump and one-motor independent circuit type and the two-pump merging series circuit type, to improve the operation performance of operation levers, and to simplify the configuration of a hydraulic circuit.