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. 13, 1994
Filed:
Oct. 13, 1992
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
In a center electrode for a spark plug, the center electrode is made of a heat-conductor core cladded with a nickel-alloyed metal. A recess is provided on the front end surface of the nickel-alloyed matrix and the columnar tip is made of a precious metal and fit in the recess in such a manner that a front end of the tip protracts from the recess. The outer surface of the tip is welded to an inner surface of the recess. The dimensional relationship of the components of the spark plug A, B, C, D, E, F and G is as follows: 0.3 mm.ltoreq.A.ltoreq.0.8 mm, 1.2A.ltoreq.B.ltoreq.3A, 0.1 mm.ltoreq.(C-A)/2.ltoreq.0.5 mm, D.ltoreq.(C-A)/2, E.ltoreq.B/4, 0 mm.ltoreq.F.ltoreq.0.5 mm and A/5.ltoreq.G.ltoreq.A/2, where A: a diameter of the columnar tip, B: a length of the columnar tip, C: a diameter of a front end of the nickel-alloyed metal, D: a length of a front end of the nickel-alloyed metal, E: a length of the front end of the tip which is protracted from the recess, F: a distance between a rear end of the tip and a front end of the heat-conductor core, G: a distance of a welding portion penetrated from the outer surface of the tip into the inner surface of the recess.