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:
Mar. 04, 2014
Filed:
Apr. 05, 2010
Naomichi Miyashita, Aichi, JP;
Mamoru Musasa, Hurricane, WV (US);
Naomichi Miyashita, Aichi, JP;
Mamoru Musasa, Hurricane, WV (US);
NGK Spark Plug., Ltd., Aichi, JP;
Abstract
An object of the invention is to restrain separation of an electrode tip from a ground electrode or from a center electrode. A spark plug satisfies a condition 0.8≦A1/A2≦1.9, where, as viewed on a section which contains a center axis (O) of an electrode tip, A1 [Hv] is hardness of the electrode tip as measured outside a circle having a radius of 0.2 mm, with a boundary point (PA) on a surface of the spark plug between a fusion zone and the electrode tip serving as the center of the circle, and A2 [Hv] is hardness of the electrode tip as measured within the circle having a radius of 0.2 mm.