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. 25, 2000
Filed:
Sep. 18, 1998
Applicant:
Inventor:
E Grant Swick, Bartlett, IL (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C23C / ;
U.S. Cl.
CPC ...
148226 ; 148230 ; 2988807 ; 29888074 ; 29557 ;
Abstract
A method and apparatus for making a piston ring in which a metal strip having a first coefficient of expansion is coiled about a special mandrel having a second greater coefficient of expansion and a threaded form that has a zero helix angle along most of its circumference or perimeter and then a relatively steep helix angle for a short distance.