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. 21, 2009
Filed:
Nov. 12, 2004
Junsei Tanaka, Hirakata, JP;
Kazuhiro Hatake, Hirakata, JP;
Junsei Tanaka, Hirakata, JP;
Kazuhiro Hatake, Hirakata, JP;
Komatsu Ltd., Tokyo, JP;
Abstract
A hydraulic pressure control device of a construction machine enabling an increase in operability and working efficiency by suppressing a fluctuation in flow rates occurring before and after the switching of a merging-separating valve, in energy efficiency by accurately determining the switching timing of the merging-separating valve to suppress the pressure energy loss of a pressure compensating valve, and working efficiency in the compound motion of plural hydraulic actuators. When a controller determines that necessary flow rates of first and second hydraulic actuators are less than maximum discharge flow rate of each of first and second variable displacement hydraulic pumps when the first merging-separating valve is in a merging position, the switching of the first merging-separating valve is controlled so that firstly the first merging-separating valve is switched to a separating position and, after the switching is completed, the second merging-separating valve is switched.