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:
Apr. 11, 1995
Filed:
Sep. 28, 1992
Applicant:
Inventors:
Assignee:
Nippondenso Co., Ltd., Kariya, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01T / ;
U.S. Cl.
CPC ...
313142 ; 313141 ; 1231 / ;
Abstract
There is disclosed a spark plug which can maintain a low spark voltage for a long period of time even if a noble metal tip is used in a small amount. A discharge gap is formed between a central electrode and an earth electrode. The noble metal tip is formed on that end face of the central electrode facing the earth electrode. A cross-shaped groove is formed in that end face of the noble metal tip joined to the central electrode. The cross-shaped groove is exposed when the noble metal tip is consumed by a discharge developing in the discharge gap.