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:
Dec. 11, 2001
Filed:
Mar. 02, 1999
Kenji Shimizu, Nagoya, JP;
Yutaka Tanaka, Kasugai, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
A spark plug assembly is produced in the following manner. Namely, an insulator having an axial through-hole with a metallic terminal fixed at an end thereof and a center electrode fixed at the other end and with packing layers of bulk powders of a conductive glass seal layer, a resistor and the like being formed in the through-hole between the metallic terminal and the center electrode. Subsequently, the spark plug assembly is heated so that the temperature of the side closer to the center electrode is higher than that of the side closer to the metallic terminal along the longitudinal axis of the insulator. Then, the packing layers of the bulk powders within the through-hole are pressed between the center electrode and the metallic terminal by applying pressure to the heated spark plug assembly so that the metallic terminal comes closer to the center electrode along the axis of the through-hole with the position of the center electrode being fixed relative to the through-hole.