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. 25, 2006
Filed:
Jun. 26, 2002
Kenichi Nishikawa, Bisai, JP;
Makoto Sugimoto, Nagoya, JP;
Kenichi Nishikawa, Bisai, JP;
Makoto Sugimoto, Nagoya, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
A method for producing a spark plug, the spark plug comprising a center electrode, a metal shell and an alumina ceramic insulator disposed between the center electrode and the metal shell, wherein at least part of the surface of the insulator is covered with a glaze layer, the method comprising the steps of: preparing a plurality of kinds of element glaze powders wherein each kind of the element glaze powders has a different dilatometric softening point and a different linear expansion coefficient compared to other kinds of element glaze powders; coating a surface of the insulator with the plurality of kinds of element glaze powders so as to form a glaze powder layer; and baking the glaze powder layer to the surface of the insulator so as to form the glaze layer by heating the glaze powder layer.