Servo control for trailer brakes - has direct operation from master cylinder with control pressure inversely proportional to servo pressure to allow fine control

摘要

The servo assisted brakes for the towing unit and trailer have a main master brake cylinder (16) operated on by the brake pedal (14) and the handbrake lever (15). The unit brakes (11) are operated directly from the master brake cylinder, which also has a connection (17) to the servo control valve (31). This links the servo pressure to the trailer brakes (21 to 24). The servo pressure is controlled by a control force inversely proportional to the available servo force to maintain a fine braking control.