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. 29, 1983
Filed:
Sep. 04, 1980
Thomas L Edwards, Almont, MI (US);
Raymond P Lambeck, Bloomfield Hills, MI (US);
Vickers, Incorporated, Troy, MI (US);
Abstract
A hydraulic system comprising a full flow supercharged variable displacement pump and a fixed displacement charge pump adapted to be driven by the same prime mover as the variable displacement pump for supplying fluid to the variable displacement pump. An orifice is provided in the supply line to the variable displacement pump, a circuit is provided from a point downstream of the orifice to tank pressure, and a feedback valve is provided in series with the circuit. The feedback valve comprises a pair of mutually and oppositely adjustable flow restrictions in series with said circuit. The restrictions are connected to the displacement varying means to vary them equally and oppositely in proportion to the movements of the displacement varying means. A speed sensing control valve is responsive to the pressure level between the two restrictions and the pressure level upstream of the orifice and is connected to the outlet of the variable displacement pump and operable to operate the displacement varying means to reduce the displacement of the pump when the pressure differential between the pressure at the outlet of the feedback means and the pressure upstream of the orifice falls below a predetermined value.