From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Patent specification for improvements in sparking plugs with an integrated heating element.
| Identifier | ExFiles\Box 142\3\ scan0136 | |
| Date | 3rd March 1936 | |
| PATENT SPECIFICATION 446,489 Application Date : March 3, 1936. No. 6476/36. Complete Specification Accepted : April 30, 1936. COMPLETE SPECIFICATION Improvements in Sparking Plugs I, WILLIAM JOHN VINCENT, of 17. The Hayes, Cardiff, of British Nationality, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement :— This invention relates to improvements in sparking plugs for internal combustion engines and more particularly to sparking plugs in which a heating resistance element adapted for connection to a low tension battery is incorporated with the plug for the purpose of heating the sparking plug to drive off moisture and facilitate ignition. The present invention has for an object an improved construction of sparking plugs of this type. In accordance with the present invention in the improved sparking plug the resistance element is provided in the form of a coil directly surrounding the lower free end of the central electrode of the sparking plug and disposed in a pocket open at its outer end so that when the sparking plug is in use the gases of combustion have access to the resistance element, one end of the coil being attached to a sleeve which surrounds a portion of the central electrode but is insulated therefrom and from the main body of the plug and is arranged for the attachment of a terminal for the supply of low tension current from a battery, the other end of the resistance element being connected to the plug body and thus earthed. The single figure of the accompanying drawing shows in cross-section a sparking plug constructed in accordance with the present invention. Referring to the drawing, 1 denotes the main body of the sparking plug and 2 the central electrode and 3 the high tension connection. The central electrode 2 is surrounded over the major portion of its length by an insulating sleeve 4 and a surrounding metal sleeve 5 to which is attached the low tension connection 6. The connection 6 may be taken from any convenient source such as a battery, the current being controlled from any convenient position such as the dash-board of a car. The sleeve 5 is surrounded by insulation 7 and is supported within the plug 1 by means of the bush 8 and gland nut 9. To the lower end of the sleeve 5 is attached a resistance element in the form of a coil 10 directly surrounding the lower free end of the central electrode 2 and disposed in a pocket open at its lower end so that when the sparking plug is in use combustion gases may enter this pocket between the plug points 11 and the central electrode 2 and be ignited by the coil in the event of failure of the sparking plug to ignite such gases. The resistance element is earthed by connection to the bush 8. As will be clear the resistance element 10 in the position shown not only serves to drive moisture from the plugpoints and heat up the plug in order to facilitate starting but also will serve as an incandescent igniter for this purpose. The igniter has the advantage that it is exposed to the gases but mounted within the plug body and is thus protected from the fuel spray when used in Diesel engines. Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is :— 1. A sparking plug provided with a resistance element in the form of a coil directly surrounding the lower free end of the central electrode of the sparking plug and disposed in a pocket open at its outer end, one end of the coil being attached to an insulated sleeve adapted for electrical connection with a supply of low tension current, the other end of the resistance element being connected to the plug body. 2. A sparking plug constructed and arranged to operate substantially as described with reference to the accompanying drawing. Dated this 3rd day of March, 1936. CRUIKSHANK & FAIRWEATHER, 65—66, Chancery Lane, London, W.C.2, and 86, St.{Capt. P. R. Strong} Vincent Street, Glasgow, Agents for the Applicant. Leamington Spa: Printed for His Majesty's Stationery Office, by the Courier Press.—1936. [Price 1/-] | ||