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. 04, 2001
Filed:
Apr. 20, 1999
Seigo Arai, Hiroshima, JP;
Kobelco Construction Machinery Co., Ltd., Hiroshima, JP;
Abstract
The invention provides a pump controller for a construction machine that allows an operator to set the maximum speed of a specific actuator arbitrarily without altering the negative control and acquire a smooth operation. The pump controller comprises a plurality of control valves to supply actuators with a controlled pressure oil, a variable displacement hydraulic pump to supply the plural control valves with the pressure oil in parallel, a center bypass connected in parallel to the control valves, and a restrictor to generate a control pressure for negatively controlling the variable displacement hydraulic pump installed at a terminal end of the center bypass. The pump controller further comprises pressure sensors to recognize the operation of the actuator, a controller that sets a pump discharge characteristic individually to the control valve for the actuator in accordance with the operation state of the actuator, calculates a pump discharge corresponding to the control pressure using the set pump discharge characteristic, and controls the angle of inclination of a regulator.