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).
The design, materials, and manufacturing of a new hydraulic shock damper piston.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan059 | |
| Date | 17th March 1931 | |
| DA{Bernard Day - Chassis Design}/HDY.{William Hardy} ) FROM R HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} ) (At Le CanadelHenry Royce's French residence.) C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} C. to HY{Tom Haldenby - Plant Engineer} RHC.{R. H. Coverley - Production Engineer} E HYDRAULIC SHOCK DAMPERS. X235. I wired Derby that the new damper piston was not good enough yet because it was difficult to cast, and it now seems we must have hardened pads for cam to work upon, and that hard bronze is not good enough. There are 2 or 3 ways that such a casting may be parted on a two box mould - no cores. (a) On end seems preferable if we must cast out some of the weight of the solid head. It must be a machine plate 2 box job. (b) Since we have to fit hardened plugs it can be any metal that will work well in the cylinder bore. Cast iron would be the cheapest but not much (if any reason for brass or aluminium) because the latter is easier to machine and better for pressing in plugs and studs. (c) Do we want to make it suitable for carrying the replenishing valves. I think yes. Every effort should be made that this will do for standard production after these bodies are used up, but the special ones for existing bodies can be machined to special dimensions if needed, and also probably new covers may be needed for the existing bodies, and these could lengthen the clearance space in the cylinder which seems different at each end. I should like to see it the same and the inside lever moving equally each side of the centre. I do not think it matters if there is space for oil in the piston: it means slightly more filling but it may rob the capacity for reserve oil - i.e. if the space could be the other side of the piston it would be more economical, but not at the expense of cores and complication. We must not uncover the port in the piston and I should like to see all square at rather under full load to make allowance for extra rebound over bumps, but if one draws EVERY thing squarely it is only necessary to shew the axle slightly lower than full load and make all the movements of equal angles. It will save much time, thought, and confusion. The drawing I have made shews a piston 4.5 long. The cylinder is 3.375 long equally on each side of the centre, a new cover lengthens that end to the 3.375 dimension, the piston moves 2" - i.e. 1" each side of the centre, and does not uncover the port at the top, but Mr. Hardy will go ahead; I cannot finish my drawing today as I want to write about two other subjects. (1) | ||