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 to the Cadillac Motor Car Co. inquiring about the advantages of American-style steering gears.
| Identifier | ExFiles\Box 170\2\ img208 | |
| Date | 19th November 1934 | |
| Exptl. Dept. RM{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}10/KW. 19th November, 1934. M.{Mr Moon / Mr Moore} Olley, Esq., c/o.{Mr Oldham} The Cadillac Motor Car Co., Detroit, Michigan, U.S.A. Dear Sir, We are at present making efforts to improve the steering of our cars by trying Steering Gears of the Cam and Roller type, as made by Marles in England and by Gemmer & Saginaw in America. As we are not certain of the advantages claimed for the American version of this gear Mr. Robotham has asked me to write for your help on this point. It seems to us that 90% of the steering Gears used in America are of the double tooth follower type, in which the groove in the roller follower engages with a tooth on the cam. In the English version of this type of gear a tooth on the roller follower engages with a groove on the cam. So far as we can see, the only advantage of the American gear is that it can be designed to give more angular movement of the rockershaft, and so allows the whole gear to be more compact and the pendulum lever to be shorter. The shorter pendulum lever reduces torque in the rockershaft, may help with the question of ground clearance, and gives a slightly greater increase of mechanical leverage in the full lock positions. It occurs to us that, apart from the above advantages, there may be some subtle advantage such as less transmission of road shocks, a lighter steering due to greater forward efficiency of the gear, or greater durability etc, although we fail to see why this should be so. However, we should be very grateful if you would enlighten us as to the general reasons why the double tooth gear is so universally used in America. | ||