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:
Apr. 24, 1990
Filed:
Feb. 14, 1989
Applicant:
Inventors:
Assignee:
Sanyo Electric Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B23P / ;
U.S. Cl.
CPC ...
148 165 ; 295274 ; 29888048 ;
Abstract
In a method for manufacturing a piston a metal piston is prepared which has a skirt tapered towards the bottom end to such an extent that a diameter of the metal piston becomes uniform after a heat treating step. The metal piston is heat treated in a gas containing nitrogen and carbon to form a nitride film layer on the outer surface of the piston and to transform the skirt.