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).
Three successive changes to a vehicle's braking and servo lever system.
| Identifier | ExFiles\Box 83\2\ scan0282 | |
| Date | 7th March 1938 | |
| ( 2 ) I/.7.3.38. Ist Change. Our mock-up. Idler Lever and all other levers as above. (Pending receipt of levers from Works.) This gives a considerable increase in servo and direct foot braking to rear. There is slightly less servo to rear than the final change made (see below) and is inferior in this respect. The direct foot to rear is increased considerably more than in the final arrangement, and we think the pedal travel would be considered excessive. The handbrake leverage is also increased by the same amount which gives a very powerful action but noticeably more travel than standard. 2nd Change. N° 3 in your memo, "With Rm.{William Robotham - Chief Engineer}496 (T Lever) and the two long levers on the cross shaft interchanged". This was not immediately explicit as there are three long levers on the cross shaft, see fig.I, but on investigation it was found that only two of the three long levers had the same size keys and pinch bolts namely, the handbrake lever and the output lever. These were therefore, interchanged, and the Rm.{William Robotham - Chief Engineer}496 idler lever fitted. This gives a slight increase in servo and direct foot to rear over the original system, but not enough to reduce the front braking to reasonable proportions. The handbrake has slightly less leverage (not more as stated in your memo, which makes us wonder if we have interchanged the levers you meant). It has very much the same feel as a standard handbrake in action. 3rd & Final Change. With Rm.{William Robotham - Chief Engineer}497, I.5625" crs. servo lever in addition to 2nd Change. This gives the best results we have so far obtained. The servo to rear is slightly higher than in the Ist change and the highest so far run on the system. The direct foot to rear is a little higher than the original, but not enough to make the pedal travel excessive. The handbrake is the same as in the 2nd change and considered satisfactory. The shorter 2.625" crs. handbrake lever has the big advantage that it brings the rod from the handbrake down clear of the damper governor control box and gearbox cross member where it just fouled before. | ||