Patent ID: 8276993

Claim:
A pneumatic brake system for a heavy duty vehicle having at least one source of pressurized air for pressurizing the brake system, at least one spring brake chamber including a spring brake assembly and at least one service brake chamber including a service brake assembly, the pneumatic brake system comprising: a first control valve in communication with the source of pressurized air for delivering pressurized air to the spring brake chamber and exhausting pressurized air to atmosphere to activate the spring brake assembly when work brake system pressure is reduced to a predetermined low trip brake system pressure; a second control valve in communication with the source of pressurized air for selectively delivering pressurized air to the service brake chamber for application of the service brake assembly; and a work brake system in communication with the source of pressurized air, the first control valve, and the second control valve, the work brake system being operably dependent on a predetermined high trip brake system pressure and a predetermined reset brake system pressure, wherein upon actuation of the work brake system, when work brake system pressure is greater than the predetermined high trip pressure, the work brake system is configured to deliver a pneumatic control signal to the second control valve to activate the service brake assembly, wherein when the work brake system pressure is reduced to the predetermined high trip pressure, the work brake system is configured to deliver a pneumatic spring brake signal to the first control valve to activate the spring brake assembly and remove the pneumatic control signal to the second control valve, wherein the delivery of the pneumatic control signal to the second control valve via the work brake system is prevented until work brake system pressure is greater than the predetermined reset pressure, wherein the predetermined reset pressure is greater than the predetermined high trip pressure; wherein the work brake system includes a control for delivering the pneumatic control signal to the second control valve, the control being remote from the second control valve; and wherein the work brake system includes an inversion valve for monitoring work brake system pressure, and a sequence valve in communication with the inversion valve and the first control valve, wherein when work brake system pressure is greater than the predetermined high trip pressure the inversion valve is configured to prevent the delivery of the pneumatic spring brake signal to the sequence valve.