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:
Aug. 21, 2001
Filed:
Sep. 09, 1999
Nobumi Yoshida, Tochigi, JP;
Hiroshi Endo, Tochigi, JP;
Komatsu Ltd., Tokyo, JP;
Abstract
An improved pressure fluid supply and delivery apparatus is disclosed that has a pressure compensating function and yet a reduced loss in pressure. The apparatus includes a variable displacement hydraulic pump unit(,) having a plurality of fluid discharge ports(,) independent each other and a common drive shaft. A plurality of fluid circuits (,) are connected to the plural discharge ports (,), respectively, and a plurality of fluid operated actuators (,) are connected via respective operating valves (,) to the plural fluid circuits (,), respectively. Also included in the apparatus is a displacement control means (,) operable in response to discharge pressures in the fluid discharge ports (,) and load pressures in the actuators (,) for controlling discharge fluid pressure of the variable displacement pump unit (,). A combining valve means (,) is disposed between the plural fluid circuits (,), for blocking fluid communication between them when the plural fluid discharge ports (,) have an equal pressure and operable to establish fluid communication between these fluid circuits via a constriction (,) in the presence of a difference in pressure between those fluid discharge ports.