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).
Sticking issues and potential improvements for a 20 HP starter mechanism.
| Identifier | ExFiles\Box 40\5\ Scan186 | |
| Date | 29th June 1927 | |
| Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. BY.{R.W. Bailey - Chief Engineer} 13587 R1/M29.6.27. 20 HP. STARTER. X.5650 X.3587 Referring to Hs{Lord Ernest Hives - Chair}2/LG24.6.27., I think Mr. Hancock's investigations are extremely good. The change in the strength of the springs is quite in accordance with anticipations. I see no reason why D.51144 should be more than 1 lb in the off position, going up to 2 lbs. when fully engaged, while D.51133 could probably be 15 lbs. Sticking in the off position ought not to take place if the pieces are passably well made. The inaccuracy may be in the assembly, due to the cork face or sheet metal work, or methods of producing the nut may be found to be defective. On one of the designs we suggested a number of surfaces at right angles to the lead of the screw thread. I am not sure that we could produce these surfaces in a practical way but it would appear an excellent scheme if we could do so. The sketch enclosed shews the suggestion. Every care should be taken that all the parts are true individually so that in turning round the assembly does not bind in the bore. I feel sure this is what is happening to make it stick in the off position. There is an impossible fibre washer. Instead of the double cone face in the off position I suggest it would be better to have a swivelling washer; perhaps a ball bearing, which would reduce the friction. E.{Mr Elliott - Chief Engineer} provides sketches herewith for - (1) Not to run up against normal surface or circumferential teeth. (2) Spherical swivelling washer. (3) Ditto - with balls. We should like to be able to douse it with oil - try thin, medium, thick. In conclusion, change springs until you get greatest reliability, and freedom from damaging gear. See all the parts are true however they move or are put together, so as not to bind in the bore on the pinion or nut. Use a face (off position) which is flat, but swivels on spherical seating. Must the teeth grab, or can they be rounded like gearbox and so not be destroyed easily? R.{Sir Henry Royce} | ||