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).
Demonstration of a Lockheed servo braking system mounted on a Wolseley 25 HP car.
| Identifier | ExFiles\Box 121\1\ scan0366 | |
| Date | 18th November 1940 | |
| -2- They showed us mounted on a Wolseley 25 H.P. car the Lockheed servo, consisting of an oil circulating pump driven from the prop. shaft. Pressure on the pedal restricts the oil circulation and builds up pressure which acts on a piston to push the master cylinder piston proper and on a smaller diameter piston to react on the brake pedal, the ratio of the two piston areas providing the required servo multiplication. Failure of the circulating pump leaves the direct braking as the pedal, then pushes direct on the master cylinder. The principle is exactly that used in a patent application by Hdy.{William Hardy} and Ev{Ivan Evernden - coachwork}/Tln. for clutch actuation, but Mr. Parnells patent dated from about 1925. Mr. Parnell emphasised that they were not necessarily trying to sell us the servo but would appreciate our opinion. As tried, the pulsations from the five cylinder pump driven at prop. shaft speed (an aero installation pump was used as being easily available for experimental purposes) could be felt on the pedal and could also be heard, but the principle appears interesting and the layout simple. The brakes were progressive and there was no shunting lag. I did not observe any dropping off as the vehicle came to rest. Ev{Ivan Evernden - coachwork}/DB.{Donald Bastow - Suspensions} | ||