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).
Proposing experimental alterations to the four-wheel brake system.
| Identifier | WestWitteringFiles\K\November1923\ Scan130 | |
| Date | 27th November 1923 | |
| TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} c. to CJ. BJ. c. to RG.{Mr Rowledge} DA.{Bernard Day - Chassis Design} c. to PN.{Mr Northey} re. FOUR WHEEL BRAKES. We are proposing experimentally to try the following alterations - The ratio of the balancing gear will be altered slightly. This however will make very little difference in the available pull going to the equaliser gear beside the engine. At this latter point we alter the ratio of the levers making the driven lever 4" instead of 2.5" and the going away levers 2.5" instead of 3.150. Further on we get little or no change and propose no alteration in the levers on the axle. Then we come to the lever on the brake shoe carrier which we propose to increase to 6" from 4 1/2". We are proposing to still use the floating fulcrum, but only .5" centres instead of .8" which expands the two shoes. The front shoe or lapper is 120° and the non-lapper is a jointed shoe approximately 120° and 60°, leaving 60° for the expander. This brake is a self 'servo' backwards, with the object of not having too much front braking forwards and ample braking backwards. All this gives us 4.3 times the original expanding effort and a great deal more than we expect will be found practical. It is quite easy to reduce this wherever convenient, but preferably at the equaliser beside the engine so as to avoid deflection in the shafts. As soon as you can determine we wish to know if 120° shoes for front braking is satisfactory with a suitable leverage to give practical working, because if still unsatisfactory we should have to self 'servo' it forwards. (1) | ||