GB1288149A - - Google Patents

Abstract

1288149 Making sparking plugs; forging; jointing by stamping CHAMPION SPARK PLUG CO 12 June 1970 [16 June 1969] 28550/70 Headings B3A B3H and B3Q A sparking plug, comprising a hollow tubular shell 10 and an insulator 34, is assembled by inserting the insulator in the shell and applying an axial force on the insulator to deform a shoulder 22 to provide an effective seat between the insulator and the shell. The shoulder 22 is formed either by inserting a die 28 into the shell or by machining. The insulator 34 is of vitreous material and it has a shoulder 38 which is preferably glazed and has a slightly different angle to the shoulder 22, the difference being at least 5 degrees. Sealing material 50, preferably a resilient material such as asbestos or talc, is packed in the space between the insulator and shell and tamped by a tool (52), Fig. 4 (not shown). A die 54 crimps the upper end 30 of the shell 10, which is then collapsed axially at a thin-walled portion 56 by the application of a high axial force to the die 54. As the shell collapses, the axial load is transmitted through the sealing material 50 to the insulator 34, which is forced downwardly to deform the shoulder 22 against the shoulder 38. Alternatively a metal gasket may be inserted in the shell over the portion 48 of the insulator and abutting its flange 36. The end 30 of the shell is crimped over the gasket and the portion 56 heated prior to being collapsed axially. A third assembly method comprises inserting the insulator and applying the axial force to deform the shoulder 22. Sealing material is then compacted between the shell and insulator, and the shell is then crimped.