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).
Suggestions for modifications and trials of a vehicle's braking system.
Identifier | ExFiles\Box 92\4\ scan0211 | |
Date | 29th September 1936 | |
-2- Suggestions to be tried with a view to an early introduction. The above proposals should give us approximately 1.875" travel at the end of the vertical lever of the yoke piece bell crank. It is desirable, we think, to increase this travel. On N.Sch.4910 herewith we show some proposals to achieve this end. 1) Using the existing bell crank lever but modified as on N.Sch.4904 with respect to the bolt boss length. It is possible by making the angle between the bell crank 110º, to start the horizontal arm of the bell crank higher up. A shorter ball ended pull rod is required and it may be necessary to open out the hole in the brake carrier plate. Existing forgings can be used up by making them hot and setting them. This modification would increase the travel at the end of the vertical arm of the bell crank lever to 2.06". On N.Sch.4910 we also show a modification to the bell crank lever end which receives the ball ended pull rod, which would enable a further increase in travel to be achieved, when the travel at the end of the vertical arm of the yoke piece bell crank would be 2.212". Further Moves to be Tried. 1) It is generally agreed that we might expect to find that we could do with less total braking on Phantom III. It is proposed therefore, to reduce the front braking by increasing the radius of the front brake cams from .52" to .6". At the same time we reduce the length of the rear brake idler lever to maintain the same ratio between front and back as now. Maintaining the present brake adjustment and the 5º of cam movement for brake clearance, the travel between the brakes on and brakes off will be unaltered, but for a given amount of drum expansion the amount of brake bell crank lever movement on the yoke piece will be reduced. We are sending you a scheme for this cam immediately. 2) In order to overcome the difference in the rate of expansion between the brake shoes and the drum, it is proposed to try aluminium brake shoes. We are sending you almost immediately a scheme for aluminium brake shoes. Att:N.Sch.4915. N.Sch.4910. EV.{Ivan Evernden - coachwork} | ||