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).
Letter from Gordon Armstrong Patent Suspension Company regarding the operation of shock absorbers sent for testing.
| Identifier | ExFiles\Box 152\1\ scan0233 | |
| Date | 12th January 1937 | |
| TELEPHONE: BEVERLEY 321 GRAMS: ARMSTRONG'S SUSPENSION. The Gordon Armstrong Patent Suspension COMPANY LIMITED OUR REF: GA.WC.5. YOUR REF: WALTHAM WORKS, OPPOSITE ST.{Capt. P. R. Strong} MARY'S CHURCH, BEVERLEY E.{Mr Elliott - Chief Engineer} YORKS. GORDON ARMSTRONG. A.M.I.A.E., F.{Mr Friese} Inst. PAT. N. O.{Mr Oldham} TILL. Messrs. Rolls-Royce Ltd., DERBY. 12th January, 1937. For Mr.Leslie's attention. Dear Mr.Leslie, We are sending to you to-night two shock absorbers for testing purposes; these both have spring-loaded valves. The shock absorber that is painted red has a very small hole in the valve rod, allowing oil to pass through the valve rod into the top recuperating chamber. The reason for this is that there is no crank angle on a two cylinder vertical job that will give exact displacement on each side on all parts of the movement. The consequence is that there is a certain amount of what we term "build-up" in certain places of the shock absorber. By this I mean that at certain positions of the shock absorber one cylinder has more oil to discharge than the other cylinder can accommodate; the consequence being that there is a hydraulic lock. Looking at it in another way; at certain positions on the shock absorber one piston is moving quicker than the other and, as far as we can make out, although we can get very near to the equal movement by the angle at which the cranks are set, there is no position that gives an absolutely true reading. If pistons etc. were not a good fit, and oil could leak past, there is no need to worry about this build-up but where pistons are a good fit in the cylinders this excessive oil cannot get away, and it is for this reason that we have put in the small hole to allow a constant leak from each cylinder. As the hole is small it does not affect the valve setting to any appreciable extent. I am giving you this information because it cont'd.... | ||