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:
Jan. 16, 2001
Filed:
Aug. 24, 1998
Seiji Kamada, Hiratsuka, JP;
Komatsu Ltd., Tokyo, JP;
Abstract
A first object of the present invention is to make do with a simple hydraulic circuit, which does not utilize a pressure compensation valve, and to enable the use of an inexpensive, low-precision pressure detector, to enable the maintenance of continuous control at all times using simple controls, and to get by without shocking the operator or the mechanical parts, and to cancel the load dependency of a hydraulic actuator flow during combined operation without limiting the control system of the hydraulic pump. In a device according to the present invention, a correction factor for correcting an control input of a operating member corresponding to a pertinent operating valve is calculated for each operating member on the basis of a ratio between a detected differential pressure across an operating valve, and a minimum differential pressure selected from among detected differential pressures across a plurality of operating valves. Then, a control input of a corresponding operating member is corrected using this calculated correction factor. Further, a second object of the present invention is to enhance work efficiency by enabling changing of pressure compensation characteristics of an hydraulic actuator in accordance with a operating lever operating state and load pressure. In a device according to the present invention, an upper limit value or lower limit value of a correction factor is set for each operating member in accordance with control input of the operating member, and this correction factor is used to correct the control input of a corresponding operating member so that a correction factor obtained in accordance with a detected differential pressure does not exceed the above-mentioned set upper limit value or lower limit value.