BRAKE ACTUATER VALVE * BRAKE SYSTEM FOR WHEEL AND BRAKE SYSTEM FOR TRACTOR AND TRAILER

摘要

A pneumatic brake system employing dual-diaphragm, spring- actuated, air-released brake actuators is provided with an inversion valve which, in the event of a brake system failure, prevents the brakes from being automatically applied while permitting controlled brake application by releasing compressed air from each actuator's spring chamber in an inverse ratio to that normally supplied from the system by the operator applied brake valve thus permitting a controlled spring brake application. The valve employs first and second pressure responsive pistons with associated valve seats to maintain the actuator springs compressed with air at supply pressure when the vehicle is normally operated. The air at supply pressure in each actuator's spring chamber is automatically ported to a lower pressure through the valve when a system failure occurs and prior to brake application to insure fast response time of the spring actuated brake.