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 considerations for the Bensport hydraulic brake transmission system.
| Identifier | ExFiles\Box 179b\1\ img138 | |
| Date | 2nd November 1932 | |
| HS.{Lord Ernest Hives - Chair} ) FROM R.{Sir Henry Royce} PA.{Mr Paterson} ) C.C. to SG.{Arthur F. Sidgreaves - MD} WDH. DH.{D. Henderson - Showroom} BENSPORT - HYDRAULIC BRAKE TRANSMISSION. R3/W2.11.32. K+-S-S3. I have spent considerable thought on this, which has led to the following conclusions: Since we are anticipated in the way we intended to arrange the automatic adjustment of the brakes, and have learned some of the difficulties in connection with this type of transmission, I have come to the conclusion that we can make the adjustment at the 'on' position nearly as easily as at the 'off' position, with the following advantages: The actuating piston can always come to zero, in which position it can close the valve face and give a double seal against gravity causing the oil to pass the actuating piston during the period of rest. I have schemed a neat and strong device for taking up the brake when the actuating piston exceeds a certain stroke. This is something like the 2 speed bicycle gear, and consists of a very small epicyclic gear with a ratchet disc on the sun wheel shaft. The load on the teeth of this ratchet need not exceed one tenth of the torque necessary to apply the brake. As regards the master cylinder it would not be wise to make this shut off the oil in its zero position, for the obvious reason that in very quickly releasing the brake some oil pressure may be trapped in the pipes which could not escape. I think also that the leather of the piston will be quite good enough to open the replenishing and release port, but I had thought that the edge of this port might destroy the leather, and that a separate valve should be used for this duty, but on further consideration one feels as though the master piston would be quite clear of the ports before the oil pressure became sufficiently high to force the leather into the port. Experience may suggest the separate valve as desirable. (We could patent it.) (1) | ||