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:
May. 31, 2005
Filed:
Oct. 31, 2002
Applicants:
Kenneth Eugene Lehrke, Maple Grove, MN (US);
Richard D. Hembree, Bellingham, WA (US);
Inventors:
Kenneth Eugene Lehrke, Maple Grove, MN (US);
Richard D. Hembree, Bellingham, WA (US);
Assignee:
Wanner Engineering, Inc., Minneapolis, MN (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F04B045/00 ;
U.S. Cl.
CPC ...
Abstract
A diaphragm pump which overcomes the problem of diaphragm failure due to overfill of the oil transfer chamber and the inability to self-prime. A notch is provided in the upper portion of the surface of the cylinder so that air can be forced back to the reservoir. In addition, the bias spring connected to the diaphragm and supported by the piston is made stiff with a spring constant that produces a bias pressure that can overcome abnormal suction pressures.