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:
Oct. 18, 1994
Filed:
Aug. 17, 1993
Applicant:
Inventor:
James E Stangroom, Sheffield, GB;
Assignee:
ER Fluid Developments Limited, Sheffield, GB;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F04B / ;
U.S. Cl.
CPC ...
417297 ; 417505 ; 137909 ; 137514 ;
Abstract
A variable displacement pump (3) comprises a piston (4) reciprocable within a cylinder (2), a displaceable inlet valve (5) adapted to control admission of lower pressure hydraulic fluid (9) to the swept volume area (10) of the piston (4) and cylinder (2), a displaceable outlet valve (7) adapted to control delivery of higher pressure fluid (9) from the swept volume area (10), and means (13, 13A, 26-28, 29-44) to control the position of the inlet valve (5) so as to control the volume of fluid (9) delivered by the pump (3) in accordance with demand.