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).
Design modification for the grouped instrument board assembly to prevent dirt ingress.
| Identifier | ExFiles\Box 15\7\ Scan121 | |
| Date | 16th November 1929 | |
| X7530 EX. - from SPT. EPC. SPT.1/B.16.11.29. Re - Grouped Instrument Board Assembly. --------------------------------- As reported in my memos. SPT7/B.11.11.29., and SPT6/B.13.11.29. we are taking special precautions to keep dirt out of these instrument boards. We have however run up against a snag which prevents the instruments from being dust and dirt proof, and we suggest that a modification in design is necessary. The trouble is that the speedometer has an adjustment hand wheel and casing fitted to the outside diameter, and a clearance has to be made in the instrument board main casing to accommodate this projecting adjustment casing. The limits on both pieces are such that there is a considerable gap at this point, and we suggest that the adjustment portion should be kept inside the outside diameter and fitted into the back of the instrument. This would then allow the speedometer spigot ring to carry right round. To make this clear I attach sketches of the instrument board casting and also speedometer. The lines marked red we wish deleting, and the design altered to conform to the lines marked black. We would also like to suggest that thin rubber rings be fitted between the spigots of the instrument and the instrument board casting. This rubber ring would accommodate slight inaccuracies in the bedding of the two faces. I should be glad if you would kindly give this matter your urgent consideration, as we are receiving many complaints from the Test Dept. that these instruments will not work, owing to the fact that foreign particles find their way into the instruments. You will see that inspite of all precautions we take, this is still possible with the design of speedometer as at present supplied. Sketches attached SPT. | ||