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. 05, 1999
Filed:
Mar. 24, 1997
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
By heating a glass sealing material, a center electrode is sealed and fixed within an axial bore of an insulator. Formation of a groove in a head portion of the center electrode makes it possible to protect the head portion of the center electrode from deformation under a pressure which is applied upon filling the glass sealing material in a powder form in the axial bore. The glass sealing material is therefore assured to flow to a peripheral side wall of a flange portion of the center electrode, thereby enhancing mechanical engagement between the center electrode and the insulator, that is, uniting strength for them. A spark plug is hence obtained with improved impact resistance and accordingly, with sufficient durability.