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:
May. 28, 1985
Filed:
Mar. 22, 1983
Rudolf Pollner, Bamberg, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
To securely seat a ceramic electrode (23, 28) in an insulator (15) of a spark plug, so that it can be sintered together with the insulator, a ceramic plug element (28) has added thereto an additive which renders the ceramic plastically deformable upon application of external energy; the additive may, for example, be a thermoplastic, which permits plastic deformation upon application of heat; or a thixotropic agent, such as glycerin, rendering the material plastically deformable when vibrated. A pellet or plug (28) is introduced into the end portion (32) of the central opening (21) of the insulator, preshaped to be slightly smaller by, for example, 0.2 mm, than the clearance opening in the insulator. The plug is then rendered plastically deformable, compressed by a plunger (34/1) acting against a counter plate (33). Either the plug or the inner surface of the bore can be coated with a conductive coating (27) including a burn-spark-resistant metal, for example platinum, which, upon compression, is not electrically interrupted. In subsequent heating steps, the additive is vaporized-off, and the plug sintered to the ceramic body which, initially, was only presintered.