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:
Feb. 23, 2010
Filed:
May. 02, 2007
Richard D. Hembree, Bellingham, WA (US);
Richard D. Hembree, Bellingham, WA (US);
Wanner Engineering, Inc., Minneapolis, MN (US);
Abstract
A hydraulically driven pump includes a diaphragm, a piston, a transfer chamber, a fluid reservoir, and a valve spool. The transfer chamber is defined between the diaphragm and piston and is filled with a hydraulic fluid. The fluid reservoir is in fluid communication with the transfer chamber via at least one valve. The valve spool is configured to control fluid flow between the transfer chamber and the fluid reservoir. The valve spool is movable to open and close an opening into the at least one valve only when an overfill condition or an underfill condition exists in the transfer chamber. The valve spool is moveable along an axis that is non-coaxial with an axis of movement of the diaphragm.