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:
Jul. 19, 2011
Filed:
May. 29, 2007
Applicants:
Shingo Miyake, Yokohama, JP;
Yoshie Tsujimi, Kawasaki, JP;
Takahisa Hirasawa, Fujisawa, JP;
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F04B 17/03 (2006.01);
U.S. Cl.
CPC ...
Abstract
An oscillating type piston is connected to an output shaft of an electric motor through a crankshaft. The piston is provided with a lip ring that slidingly contacts a cylinder. The motor is rotated forward and reversely by using a control circuit. Thus, different regions of the piston are subjected to a load during forward rotation of the motor and during reverse rotation thereof. Accordingly, wear of the lip ring can be distributed to different regions thereof.