Improvements relating to foot valves for compressed air tractor-trailer braking systems

Abstract

Abstract 732,959. Fluid-actuated valves. WESTING- HOUSE BRAKE & SIGNAL CO., Ltd. Dec. 3, 1953 [Dec. 22, 1952], No. 33582/53. Class 135. [Also in Group XXXIV] A pedal-operated driver's brake control valve for tractor-trailer vehicle units comprises a casing 1 within which are aligned pistons 2 and 3. The space 38 between the pistons is connected by port 36 to the trailer brake pipe. Annular spaces 21 and 22 formed in the piston 3 are connected respectively by ports 33 and 34 to the tractor and trailer reservoirs and space 39, below piston 3, to the trailer brake pipe by connection 35. Depression of the pedal 10, resisted by spring 19 seated on a fixed abutment 20, causes a self-lapping action of the valve 28 allowing exhaust through passage 18 and port 14 to atmosphere, and the valve 29 allowing fluid to pass from the trailer reservoir to the trailer brake pipe. A similar action with respect to the tractor takes place with valves 281 and 29<SP>1</SP>, but since the adjustable spring 31 must first be compressed before the exhaust port 15 is cut off, the tractor brakes are applied after, and at a lower pressure than the trailer brakes. In the event of a break in the trailer pipe, connected at 36, the piston 2 will force the piston 3 downwardly to operate the tractor brakes by direct mechanical action through the flutes 17.

Inventors

No inventors recorded.

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