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:
Mar. 17, 1987
Filed:
Sep. 20, 1984
Shinichi Yokoi, Aichi, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
A ceramic glow plug includes an unjacketed ceramic heater formed by a coiled heating wire of a high melting point tungsten alloy having a specific resistance of at least 10 .mu. ohms/cm.sup.3 embedded within a sintered ceramic body. The ceramic body has a diameter D of not more than 4.0 mm and is fitted into a hollow metallic cylinder with a tip portion thereof projecting less than three times its diameter D beyond a first axial end of the cylinder. The other end of the metallic cylinder is fitted into a mounting sleeve. The coiled portion of the heating wire is disposed substantially entirely within the projecting tip portion of the ceramic body. A resistor of iron or nickel wire may be positioned in the sleeve and connected in series with the heating wire for inhibiting overheating of the ceramic heater.