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:
Oct. 23, 2012
Filed:
Sep. 18, 2009
Mai Nakamura, Inazawa, JP;
Akira Suzuki, Nagoya, JP;
Mai Nakamura, Inazawa, JP;
Akira Suzuki, Nagoya, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug is provided which can ensure gastightness between a metal shell and an insulator while preventing the cracking of the insulator. There is provided a spark plug in which a ledge portionis formed on the metal shellwhose inside diameter is reduced gradually towards a front end portion, a step portionis formed on an insulatorwhose outside diameter is reduced gradually towards the front end portion and which confronts the ledge portion, and packingis disposed between the ledge portionand the step portion, characterized in that a distance between the ledge portionand the step portiongets narrower as the ledge portionand the step portionextend radially inwards, and in that an angle θ formed by the ledge portionand the step portionis one degree or larger and 10 degrees or smaller.