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 discussing the deflection and load characteristics of a stiffened clutch cover assembly.
| Identifier | ExFiles\Box 130\3\ scan0149 | |
| Date | 1st December 1940 | |
| Rm{William Robotham - Chief Engineer}/CB.11/BT.{Capt. J. S. Burt - Engineer}01.12.40 - 2 - It will be seen that the assembly with the stiffened cover deflects only half as much as the standard assembly for any given load. It is obvious, therefore, that the cover pressing is responsible for most of the deflection in the clutch. We expect the clutch with the stiffened cover pressing to be free from lever flutter, but we have not yet had an opportunity of testing this. A sketch of the cover stiffening is enclosed. In paragraph 3 of your letter, you state that the centrifugal assistance approximately doubles the load on the pressure plate at 3500 r.p.m. The pressure plate load due to the springs is 1215 lb. (nine 135 lb. springs). The plate load due to centrifugal action, we make 656 lb. at 3500 r.p.m., which is only a little over half the spring load. In arriving at this figure, we took our dimensions from actual levers. A ¼" hole through the weights will bring the period up to 3900 r.p.m., which is still within the working range (see graph No.3). In addition, a 20% reduction in deflection is not enough. We have therefore not tried the effect of drilling holes through the weights. Having shown that the cover pressing is responsible for most of the lever movement, we look to you for a much improved design of this article. Yours faithfully, | ||