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. 18, 1994
Filed:
Mar. 29, 1993
Kiyoshi Shirai, Kawasaki, JP;
Teruo Akiyama, Kawasaki, JP;
Shigeru Shinohara, Kawasaki, JP;
Naoki Ishizaki, Kawasaki, JP;
Takahide Takiguchi, Kawasaki, JP;
Kabushiki Kaisha Komatsu Seisakusho, Tokyo, JP;
Abstract
This invention aims at providing a hydraulic circuit apparatus for supplying pressurized fluid into cylinders for a work implement arranged such that during normal operation of the work implement the flow rate of fluid discharged by a pump is controlled such that the difference between the discharge pressure of the pump and the load pressure is always kept constant, whilst during inching operation of the work implement the flow rate of fluid discharged by the pump is reduced. This circuit apparatus comprises a large diameter piston (9) for actuating a displacement regulating member (8) of a variable displacement pump (2) in a direction as to reduce the displacement of the pump; a small diameter piston (10) having pressure receiving chamber (10a) connected with discharge passage (2a) of the pump and adapted to actuate discharge regulating member (8) in a direction as to increase the displacement of the pump (2); a load sensing valve (11) for connecting or disconnecting pressure receiving chamber (9a) of the large piston (9) with or from the discharge passage; and apparatus (12, 13, 14) for applying a force to the load sensing valve to push its spool in a direction as to communicate the discharge passage (2a) of the pump with pressure receiving chamber (9a) of the large piston.