GB144632A - Improvements in and relating to sparking plugs - Google Patents

Abstract

144,632. Brewster-Goldsmith Corporation, (Assignees of Brewster, C. W.). June 9, 1919, [Convention date]. Sparking-plugs.- Passages and surfaces at the inner end of the plug are formed so as to promote the scouring of the insulator and electrodes. The mica insulation 3, 4, 5 is combined with a gland 11, the insertion of which tightens in position a tubular member 8. The provision of this sleeve 8 results in the formation of inner and outer chambers 6, 19, the outer being in communication with the atmosphere or otherwise cooled, and the inner having a floor sloping towards the inner end of the central electrode but separated therefrom by a gap 10. The earthed electrode is formed on a ring member formed on or secured to the inner end of the casing, the member increasing in thickness from the sparkgap towards the casing, and having passages 23 directed upwardly or outwardly towards the under. side of the end of the sleeve 8, which diverts the blast across the opening 10 and on to the sparkgap. In modifications, the sleeve 8 is omitted and the surfaces 9, 24 formed on an internal projection in the casing. Gas tightness about the mica wrapping 3 is ensured by the provision of a soft-metal conical bush 14. The mica is treated with linseed oil to prevent the absorption of engine oil and carbon. According to the Specification as it became open to public inspection under Sect. 91 (3) (a), a space is preferably left between the washers 5 and gland 11. Also, the bush 14 may be of mica integral with the member 5. This subject-matter does not appear in the Specification as accepted.