GB246791A - Improvements relating to fluid pressure braking apparatus - Google Patents

Abstract

246,791. Westinghouse Brake & Saxby Signal Co., Ltd., (Assignees of Compagnie des Freins Westinghouse.). Jan. 31, 1925, [Convention date]. Fluid - pressure.- Vacuum brakes for automobiles &c. are provided with control valves in which the displacement of a diaphragm or its equivalent through a spring by a pedal or lever operated control rod effects the opening and closing of two valves controlling communication between the brake cylinder and the atmosphere and a vacuum reservoir respectively. The control pedal is connected to a rod T which displaces a diaphragm D through a spring R and a piston P enclosing the spring. The upper side of the diaphragm is open to the atmosphere through a port K' and the lower side is open to the brake cylinder. The passage C leading to the brake cylinder is normally in communication with the atmosphere through a valve S' and ports O, O<1> in the cylinder and valve casing respectively. On raising the diaphragm and piston by the rod T, the valve S' is first closed and a valve S is then raised by a stem t connecting it to the valve S<1>. The valve S opens communication between the passage A to a vacuum reservoir or pipe and the brake cylinder passage C. The downward pull of the vacuum on the diaphragm will cause the operator to feel the braking pressure, and will maintain the braking pressure determined by the pull on the rod T, as any variation in this pressure will open one or other of the valves S, S<1>, which are both closed when the parts have attained equilibrium.