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).
Design and modification of a brake servo linkage and balancer system.
| Identifier | WestWitteringFiles\L\April1924-June1924\ Scan66 | |
| Date | 1st May 1924 | |
| Br.{T. E. Bellringer - Repair Manager} FROM DA.{Bernard Day - Chassis Design} SECRET. DA{Bernard Day - Chassis Design}1/MS. 5. 24. Copy to CJ. " HS.{Lord Ernest Hives - Chair} " WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C.111. BRAKES. Y9940 Herewith we send N.Sch. 1801. shewing the arrange- ment of the linkage to suit servo shewn on Lec. 1867. etc. and balancer N.Sch. 1799. The latter has been slightly modified in the end section to suit corresponding modifica- tions on Lec. 1867. RRM. Des.60. only is now required - M.Des.60 is scrapped. The proportion of the vertical arm of balanc- ing lever is awaiting the determination of the distribution of braking to front and rear for open and closed cars, by the Exp. Dept. With the 1.8 lever on the pickup counter- shaft and 1/1 ratios on front brake countershafts and differ- ential, an equal pull is delivered to each of the 4 brakes. But this may be too much to the back in most cases. Strict- ly speaking to suit this 1.8 lever the balancer should be divided with one arm 3.08 long and the other 4.82 long, which would keep the suspension links stationary. But until this point is finally determined an equally divided lever as shewn may be used, since it only means that the whole balancing lever moves backward in taking up the front brakes. We are under the impression with a fully load- ed{J. L. Edwards} car as brought down here on Tuesday last, the distribution was not bad, though still a little too much to rear. We believe however that this car was not exactly coupled up as intended and it would be interesting to know the exact leverage obtained. Another point is that the direct leverage shewn here may be rather too much, though it is the same as 40/50, and in that case the 2.375 lever on the countershaft connec- ted to the pressure screw should be reduced. We think that at least 2 cars (open and closed) should be fitted up with RRM. Des.60. using the latest parts that are available, and the questions of ratio Direct pressure Servo pressure, and of distribution of braking to front and back, to get the best results, investigated in detail. If more pressure is wanted to the front we propose to alter the sheet metal lever on the front brake differential, as has already been done experimentally. DA.{Bernard Day - Chassis Design} | ||