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).
Investigations into the causes of knocking in hydraulic shock absorbers.
| Identifier | ExFiles\Box 68\2\ scan0225 | |
| Date | 27th April 1928 | |
| Y8520 To Na{Mr Nadin}; from Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} c. to BJ. c. to BY.{R.W. Bailey - Chief Engineer} HS{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG27.4.28. Y235 RE. KNOCKS ON HYDRAULIC SHOCK ABSORBERS. With reference to Na{Mr Nadin}3/B6428. We sent a full report - ref. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG23.4.27 and Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG26.3.28. on our investigations in connection with knocks on the hydraulic shock absorbers to Mr. Olley as soon as the tests were completed. Briefly the knock was caused by :- (1) Slackness in the main lever bearing. This was cured by improving the fit of these bearings and the lubrication thereof. (2) A noise due to the high pressure valve coming on its seating. This was cured by allowing a cushion of oil below the high pressure valve. (3) A hydraulic knock. This was cured by increasing the size of the air vent. At the present moment knocks are confined to cases where the air vent has become blocked up due to foreign matter choking the small orifice. We are considering fitting a filter to protect this somewhat vulnerable feature. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} | ||