An improved mechanical joint structure is provided and adapted for positively retaining a heating element within a bore of a body of a glow plug. The glow plug includes a body, a heating element and a ferrule. The ferrule is sealingly positioned radially between an internal surface of the body bore and...http://www.google.com/patents/US5084607?utm_source=gb-gplus-sharePatent US5084607 - Interference connection between a heating element and body of a glow plug
