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A Clever Lockheed Idea
Page 73
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UPPLEMENTING the information K./given in a short article on page 341 of this issue, concerning Lockheed brake developments, another direction in which the Lockheed concern is displaying progress is in connection with a new and ingenious form of master cylinder, for use with the company's
normal hydraulic braking system, so as to meet the requirements of heavy vehicles, where it is desired to obtain a reasonable brake-pedal pressure without recourse to servo devices. Briefly, the system consists of a double piston working in two tandem cylinders of differing diameters, as shown in the partly sectioned drawing reproduced.
During the first part of the pedal movement fluid is rapidly ejected from the large cylinder, passing around the cup washer on the small part of the piston and so flowing to the pipe lines; in this way the shoes are quickly brought into contact with the drums. Pressure is then built up in the system, which has the effect of closing a valve in the piston, so bringing the smaller cylinder into aetion ; owing to the re dudes] area the shoes can then forcibly be applied with quite a reasonable pedal pressure.
This hydraulic device, therefore, constitutes an effective and practical counterpart to the double-leverage Principle sometimes used in mechanical systems. It will be displayed by the maker at the forthcoming Olympia Show, and, in common With other Lockheed products, is made at the new works built by this concern at Leamington.