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:
Sep. 30, 2003
Filed:
Jun. 10, 2002
Applicant:
Inventors:
Assignee:
NGK Spark Plug Co., Ltd., Aichi, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F23Q 7/22 ;
U.S. Cl.
CPC ...
F23Q 7/22 ;
Abstract
A heater has a seal structure formed by inserting a shaft-like member into a stepped bore formed in a tubular member , and setting an O-ring on an upper surface of a stepped portion of the stepped bore , a clearance between the shaft-like member and tubular member being thereby sealed with this seal structure. A seal region is formed on the upper surface of the stepped portion of the stepped bore , and a conical introduction port portion extending divergently in the rearward direction from the seal region toward an opening of the stepped bore is provided. Moreover, a cone angle &agr; of the introduction port portion with respect to an axis L of the tubular member is set to not larger than