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).
List of claims for an improvement or modification to a patent for a combined indicator and spark plug.
| Identifier | ExFiles\Box 165\4\ img049 | |
| Date | 28th March 1928 guessed | |
| -4- (1) The improvement in or modification of the invention described in the specification of our prior application for Letters Patent No. 37,024, dated December 14, 1928, which consists in combining the indicator therein claimed with the spark plug of an internal combustion engine. (2) A combined indicator and spark plug according to claim 1, in which the thrust member connecting the diaphragm or equivalent with the relatively rigid member controlling the rheostat of the indicator houses one of the electrodes of the spark plug. 3.) A combined indicator and spark plug according to either preceding claim in which one of the electrodes of the spark plug is mounted on the diaphragm or equivalent of the indicating member. (4) A combined indicator and spark plug according to any preceding claim in which provision for cooling the diaphragm or equivalent of the indicator also provides for cooling one or both of the electrodes of the spark plug. (5) A spark plug with side and central electrodes provided with means for circulating a cooling fluid about the central electrode. (6) A combined indicator and spark plug constructed substantially as therein described. | ||