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).
Alterations and test results for a new design of jack ram.
| Identifier | ExFiles\Box 140\2\ scan0147 | |
| Date | 13th February 1939 | |
| - 3 - Messrs. Rolls-Royce Ltd. 13th February, 1939 fact that our 15" two stage rams of the latest type have not been in production, but only tested-out by ourselves over a considerable period individually. These tests, however, have proved very successful and have shown that the new design eliminates a number of potential sources of trouble existing both in our D.W.S. design and the existing Jackall product. The new design provides for the removal of any jack from its attaching bracket without disturbing other portions of the car which, unfortunately occurs with the existing equipment. The alterations required to the jack rams would be :- (a) Elimination of the screwed lock rings in favour of a contracting housing. (b) Elimination of the screwed top cap and pressure joint in favour of a dome-ended tube. (c) Elimination of the gland pressure joint as in the case of the existing Jackall jacks. (d) The use of external glands instead of internal piston glands which require a highly finished and carefully inspected bore. (e) The addition of a scraper ring in the gland housing to protect this from abrasive matter or mineral oil applied inadvertently to the ram tubes. The spring return mechanism, the thickness of tube and the amount of bearing surfaces are the same as those employed on the original D.W.S. jacks. For your information, four jacks utilising the new glands have been on a destruction test for eleven months and have shown no signs or leaks or structural defects. The new distributor box has been tested over -contd- | ||