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. 30, 1986
Filed:
May. 28, 1985
Hitachi Construction Machinery Company, Inc., Tokyo, JP;
Abstract
A hydraulic circuit system for civil engineering and architectural machinery having at least first and second hydraulic pumps, a plurality of actuators driven by hydraulic fluid from said pumps, and a plurality of directional control valves for controlling the direction and flow rate of the hydraulic fluid supplied from the pumps to the actuators. In the directional control valves, a first boom directional control valve and one of right and left travelling directional control valves are connected to the first pump in parallel with each other, a swing directional control valve, an arm directional control valve and a second boom directional control valve are connected to the second pump in parallel with one another, and the other of the right and left travelling directional control valve is connected in tandem to the swing, arm and second boom directional control valves at a location downstream thereof. A connecting line is provided for communication between an inlet port of the one travelling directional control valve and an inlet port of the other travelling directional control valve.