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.

Date of Patent:
Aug. 14, 2018

Filed:

Dec. 20, 2013
Applicant:

Kobelco Construction Machinery Co., Ltd., Hiroshima-shi, JP;

Inventors:

Naoki Goto, Hiroshima, JP;

Koji Ueda, Hiroshima, JP;

Kazuharu Tajima, Hiroshima, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F15B 11/17 (2006.01); E02F 3/42 (2006.01); F15B 13/06 (2006.01); E02F 9/22 (2006.01); E02F 3/32 (2006.01);
U.S. Cl.
CPC ...
E02F 3/425 (2013.01); E02F 3/32 (2013.01); E02F 9/2235 (2013.01); E02F 9/2242 (2013.01); E02F 9/2267 (2013.01); E02F 9/2285 (2013.01); E02F 9/2292 (2013.01); E02F 9/2296 (2013.01); F15B 11/17 (2013.01); F15B 13/06 (2013.01); F15B 2211/20538 (2013.01); F15B 2211/20546 (2013.01); F15B 2211/20576 (2013.01); F15B 2211/30565 (2013.01); F15B 2211/31535 (2013.01); F15B 2211/411 (2013.01); F15B 2211/41509 (2013.01); F15B 2211/6313 (2013.01); F15B 2211/665 (2013.01); F15B 2211/71 (2013.01);
Abstract

A boom cylinder circuit is provided with a boom control valve for controlling supply and discharge of hydraulic oil to and from a boom cylinder, and a merge switching valve operable to be switched between a supply position at which hydraulic oil is suppliable from a first hydraulic pump to the boom control valve, and a blocking position at which a flow of hydraulic oil is blocked. A controller switches the merge switching valve to the blocking position when a combined operation of a boom lowering operation and an arm pushing operation is detected by pilot pressure sensors, and switches the merge switching valve to the supply position when only one of the boom lowering operation and the arm pushing operation is detected.


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