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).
Details on the design of an indicator cylinder and bumper test procedure for a shock absorber.
| Identifier | ExFiles\Box 170\2\ img048 | |
| Date | 29th May 1931 guessed | |
| (3) (5) Size of Indicator Cylinder. Naturally the ordinary steam indicator piston is too large for indicating oil pressure because too much liquid would have to be displaced by the shock absorber piston to draw the diagram. Naturally the oil used for operating the indicator does not shew up on the diagram. We therefore made our indicator piston .5" dia. In order to get a diagram 1.9" high, the piston had to move through .380" i.e. displaced .08 cu. ins. of oil. From this you will see that except over very short strokes with very long levers to the axle, the amount that has to be added to the shock absorber diagram to compensate for this lost movement is negligible. Actually with the shock absorber piston having an area of 2.4 sq.ins., the main lever 12.75" long, and the intermediate lever 1.7" at 1" axle movement, we add 10% to the shock absorber diagram area to allow for displacing the .5" dia. piston. The actual type of steam indicator we are at present using is made by A.G. Thornton & Co. 109 Deansgate Manchester & called the New Style Tabor Indicator 416. (6) Bumper Test. The diameter of the drums we use on the bumper test is 4 ft. We run them at 105 RPM. which is equivalent to 15 MPH. with 2" cams. Please ask us if you want to know anything further about this piece of apparatus. Yours faithfully, [Diagram of a lever with dimensions] <-- 12.75" --> [Diagram of a lever system with dimensions] ^ 1.7" v [ ] 2.40" [Handwritten calculation] Area of Indicator Piston / Area of Shock Absorber Piston = .25 / 3.04 = .033 [Handwritten notes and sketch] .625" ^ Indicator Piston .5" dia 2.5" [Handwritten note with sketch] ^ Diagram Height 1.90" | ||