Automobile air brake safety valve - is for automatic application of trailer brakes if pressure fails on lorry brakes

摘要

The front brake circuit (1) has a control valve (4) feeding two pipes (7) (8). The rear brake circuit (2) is similar. The trailer circuit has control valve (14) one side fed by a pipe (15) in the front brake circuit and the other by a pipe in the rear brake circuit (16). A third valve entry goes to an air reservoir (17) and another by a pipe (19) to a relay valve (18), going via a pipe (10) to the trailer brakes using a separate reservoir (21). The relay valve is also connected to the front brake reservoir (6) and its control valve (4). Loss of pressure to the vehicle brakes automatically applies the trailer brakes.