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).
Cause and potential cure for knocks in hydraulic shock dampers.
| Identifier | ExFiles\Box 55\4\ Scan017 | |
| Date | 10th February 1927 | |
| X235 To BY.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/RmL/LG10.2.27. HYDRAULIC SHOCK DAMPERS. X8520 We are trying to cure knocks on the hydraulic dampers. The only incurable knock is occasioned by play between the main lever and its bush. We find that .002" clearance can produce an audible mechanical knock. This takes a considerable period to wear if the lever is fitted up initially with .0005" clearance. If, however, the best possible job is not made of the lever and bush, as in a case we recently found where there was .0015" clearance when the damper left the coachbuilders, these knocks are going to cause a lot of trouble. Can anything more be done in the way of selective assembly or machining to make a 100% job? The job is rather like a gudgeon pin, once hammering starts it goes rapidly and a very little wear causes a knock, but we cannot very well get gudgeon pin limits. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||