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:
Dec. 04, 1984
Filed:
Nov. 21, 1980
Applicant:
Inventor:
Louis-Claude Porel, Rambervillers, FR;
Assignee:
Hydro Rene Leduc, , FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F04B / ; F04B / ;
U.S. Cl.
CPC ...
417270 ; 417298 ; 417510 ; 417515 ;
Abstract
A hydraulic pump having spring loaded valves utilizes a spring providing a constant spring force and a spring providing a varying spring force. The varying spring force depending upon the position of the pump piston. The pump suction valve opens after a variable delay relative to the beginning of the piston suction phase when the pressure prevailing in the pump's dead chamber falls below a predetermined value. Abrupt decompression to the dead chamber is therefore avoided resulting in reduced energy consumption and noise level.