Dowell & Dowell
Air brake valve system
 An air brake control system for use in truck trailers having at each axle compressed-air brakes including spring brakes and service brakes, and each trailer being coupled to receive compressed air through an emergency (supply) gladhand and to receive service brake signals through a service (control) gladhand, the invention comprising an integrated brake valve system for each axle of each trailer, including a common valve housing; a spring brake valve cluster having a non-return check valve connected to receive and pass air pressure from the emergency gladhand and to deliver it directly to the spring brakes and an air pressure responsive shuttle operative to open the check valve whenever the emergency 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 gladhand pressure; and including an air tank supply valve cluster connected between the emergency gladhand and the tank and operative to sense pressure in the emergency gladhand and to open at a tank-filling threshold pressure above the predetermined spring brake isolation pressure to pass air to the tank and having a tank protecting check valve to prevent backflow of air from the tank; and including a pressure amplifying service brake relay valve cluster connected between the tank and the service brakes to supply and modulate air to the latter responsive to variations in the service gladhand pressure. 
Hose America, Inc.
B B
B60T B60T
inventional inventional
Sergio
Campanini