US 5,172,958 AGranted

Air brake control valve system

AssigneeTramec, L.L.C.

InventorEdward D. Sell

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Abstract

An air brake control system for use in truck trailers, including tandem trailers, having at each axle compressed-air spring brakes and service brakes with each trailer being coupled to receive compressed air through an emergency (supply) gladhand and to receive service brake signals through a service (control) gladhand and which includes an integrated brake valve system for each trailer within a common valve housing. Each integrated brake control valve includes a spring brake valve cluster having a non-return check valve connected to receive and pass air pressure from the emergency supply and deliver it to the spring brakes and an air pressure responsive shuttle operative to open the check valve whenever the emergency supply line pressure falls below a predetermined spring brake isolation pressure above which the spring brake holding pressure is not affected by fluctuations of the emergency supply pressure; an air tank supply valve cluster connected between the emergency supply and a reservoir and operative to sense pressure in the emergency supply and to open at a spring brake threshold pressure above the predetermined spring brake isolation pressure to pass air to the reservoir and to close air passage to the reservoir to prevent supply line pressures from dropping below the threshold level during failure of the system elements; and a non-compounding valve cluster for releasing service brake pressure to atmosphere whenever, due to a loss of pressure in the emergency supply lines, the spring brakes have been activated.

A vehicle brake system having brake means including spring brakes having actuator means which is compressor air operated to hold the spring brakes "OFF" and including service brakes operative above a minimum service brake pressure to apply the service brakes and the system including, a reservoir tank, an emergency supply line through which supply air is supplied to the spring brakes, a brake control valve means comprising:

a) a housing having a service brake input port and an emergency supply inlet port, at least two spring brake ports, a reservoir tank outlet port, and a spring brake exhaust port;
b) a first valve cluster mounted within said housing intermediate said supply inlet port and said spring brake ports, said first valve cluster being operable to open said spring brake ports to said supply inlet port immediately upon the application of supply pressure to said supply inlet port and until a maximum supply pressure is achieved at said supply inlet port, said first valve cluster being operable to close said spring brake ports from said supply inlet port upon a subsequent decrease in supply air pressure at said supply inlet port from said maximum supply pressure to thereby retain the spring brakes in an "OFF" position until such time as said supply line pressure at said supply inlet port drops below a predetermined spring brake isolation pressure below which said first valve cluster opens to communicate said spring brake ports to said spring brake exhaust port and thereby allowing the spring brakes to be "ON";
c) a second valve cluster mounted within said housing and intermediate said supply inlet port and said reservoir tank outlet port, said second valve cluster including a shuttle means for sealing said reservoir outlet port from said supply inlet port until the supply pressure at said supply inlet port is above a threshold pressure for said spring brakes which is below said maximum pressure, said shuttle means opening at pressures above said threshold pressure to thereby allow said supply air pressure to be applied to said reservoir outlet port;
and
d) a third valve cluster mounted between said supply inlet port and said service inlet port, said third valve cluster being operable to discharge said service inlet port to atmosphere upon the supply air pressure at said supply inlet port falling below said spring brake isolation pressure to thereby prevent compounding of service brake pressure in the braking system when the spring brakes are "ON".

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Abstract

Claims11