GB656468A - Improvements in sparking plugs for internal combustion engines - Google Patents

Abstract

656,468. Sparking-plugs. DEVAUX, R. H. Jan. 7, 1948, No. 552. Convention date, May 23, 1947. [A Specification was laid open to inspection under Sect. 91 of the Acts, July 10, 1948.] [Class 7(iv)] In a sparking plug having a central insulator 3 axially traversed by an electrode 1, the middle part of the insulator is of increased diameter formed with upper and lower conical seatings, and between the lower seating and the plug body 9 is disposed the upper part of a frusto-conical sleeve 13 of stainless metal, such as nickel, which extends into the annular space between the lower part of the insulator and the plug body and has its lower part 14 bent at right angles to engage with the bottom of the insulator so that a spark between the electrode and the sleeve will contact the insulator. The head 2 of the electrode 1 is screwed or caulked into the insulator and contacts a carbonaceous resistance 4. A brass terminal 5 is screwed into the insulator and a contact spring 6 is interposed between this terminal and the resistance 4. The insulator may comprise kaolin with 10-15 per cent by weight of asbestos therein or alumina, corundum, steatite, melted quartz or mica, and is ,held in the plug body by a nut 10, a washer 12 of aluminium, copper or brass being positioned between the nut and the insulator. The plug carries a washer 16 comprising a deformable asbestos ring 17 in an envelope of copper, brass or aluminium, and a deformable jointing ring 7 is compressed between the insulator and a washer 8 carried by the terminal 5. The lateral wall of the sheath is provided with longitudinal slots, Fig. 2 (not shown).