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:
Mar. 14, 1989
Filed:
Aug. 28, 1987
Kurt R Lonnemo, Bloomfield Hills, MI (US);
Vickers, Incorporated, Troy, MI (US);
Abstract
A hydraulic control system comprising a hydraulic actuator having opposed openings adapted to alternately function as inlets and outlets for moving the element of the actuator in opposite directions, a pump system for supplying fluid, and a directional valve provided to which the fluid from the pump is supplied for controlling flow to and from the actuator. A pair of lines extends from the directional valve to the respective openings of the actuator. A controller alternately supplies a first fluid pilot pressure to pressure reducing valves associated with the directional valve for reducing the pressure from the pump system or any other source and supplying a second reduced pilot pressure to the directional valve for controlling the flow to and from the actuator. Preferably, the directional valve comprises a meter-in valve and a meter-out valve associated with each line to the actuator for controlling flow out of the actuator. Each meter-in valve and meter-out valve is operated by the second pilot pressure from the pressure reducing valve.