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).
Calculation sheet for the torque required on 40/50 servo gears, including leverage diagrams.
Identifier | ExFiles\Box 16\3\ Scan017 | |
Date | 14th December 1927 | |
X7370 Hs{Lord Ernest Hives - Chair}/Rml/LG14.12.27. TORQUE ON 40/50 SERVO GEARS. Maximum torque required from brakes is to lock the rear wheels on dry concrete. Take limousine car 8-EX : Rear wheel weight 32 cwts. = .8 .. Pull at rear tyres 25.6 cwts. Pull at 17" drum 48 cwts. Normal pressure required on shoes, brake lining friction being .3 = 144 cwts. .. Servo must produce this pull through existing leverage. [Diagram text] .5" 4.5" 2.15 3.35 2.5" 2.5 2.5 / 1.7 2.05" --> P 3.8 5.575 3.8 Pull required at P. assuming EAC.7. leverage :- 144 X .5/4.5 X 3.35/5.50 X 1.7/2.5 = 6.6 cwts. This is equivalent to a pull at the end of the servo 2.05" lever of :- 6.6 X 7.6/5.575 = 8.7 cwts. at 2.05" lever. Or torque from servo plates and servo driving shaft of 160 lbs.ft. say 170 lbs.ft. to allow for modifications to drums or leverage. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||