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).
Seizure of brake idler levers due to rust and proposing a cheaper design using stainless steel bushes.
| Identifier | ExFiles\Box 92\4\ scan0302 | |
| Date | 6th February 1937 | |
| X 306 E from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c to Ma. c to Du. c to EV.{Ivan Evernden - coachwork} Rm{William Robotham - Chief Engineer}/ADM1/M.6.2.37. Brake Idler Levers - Ph.III. We have had a case recently of the idler lever shown in N.Sch. 4569 rusting up solid and holding the brake on. Seizure occured in the several plain pin joints, which had to be dismantled with a drift and also in the elaborate Oilite bushed bearing. Throughout the various chassis it is our custom in similar cases to use hardened pins in either brass bushed or plain steel holes for the heavily loaded bearings, this being inexpensive, but to provide Bijur lubricated or Oilite bushes for the lightly loaded bearing, which turns through the same angle. This seems a very unbalanced design which is unnecessarily expensive. We attach a sketch of a much cheaper type of bearing in which the rubbing surfaces can both be stainless steel bushes. The bushes can have collars on them to prevent them coming out, as is done on the Bentley front toggle shaft. We would like a replacement scheme for N.Sch. 4569 preparing on these lines, we think it would be less likely to rust up. If the lever in question did not have to take a side thrust due to wheel movement we would have suggested a plain pin joint using a stainless steel pin. Rovers can afford to use stainless steel pins and so can we if we make the designs simple. Any degree of hardness can be obtained in stainless steel. As regards the end of the lever not shown on our sketch we suggest that soft stainless bushes should be pressed into the lever and hard stainless pins should be used. The clearances should be generous. Alternatively the soft bushes can be brass. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||