Function of parking brake

L42.20-0064-09

Parking brake system shown on vehicle with code B16 and trailer brake system, code B43

1.01 Single-cylinder air compressor

4.03 Four-circuit protection valve

5.01 Single-chamber compressed-air reservoir

6.01 Manually operated water separator

6.13 Single-chamber air drier

8.01 Check valve

18.05 Trailer control valve for two-line brakes

20.05 Pulling spring actuator

28.03 Loaded shuttle valve

35.02 Supply coupling head

35.03 Brake coupling head

38.02 Test connection

38.05 Charging valve

II Instrument panel

9.01 Red indicator lamp

9.03 Stop lamp

10.01 Off switch

13.02 2-circuit service brake valve
(without front axle control)

14.09 Parking brake valve with trailer control and pipe fracture protection

16.01 Ventilating relay valve

Function of compressed air-operated parking brake with code B16

When the parking brake valve (14.09) is actuated, the spring actuators (20.05) are vented. This leads to a pressure reduction in the spring actuator cylinder.
The pressure drop releases the stretched actuating spring

which pulls the actuator piston by the piston rod and the wheel brake is applied.
The brake is released by pressurizing the spring actuators (20.05).

Function of parking brake with code B19

When the parking brake valve is actuated, the central spring actuator is vented. This leads to a pressure reduction in the spring actuator cylinder. The pressure drop releases the stretched actuating spring which pulls the actuator piston by the piston rod and the brake shaft attached to it. Two adjustable control cables on the brake shaft transmit the force of the spring actuator to the drum brakes.
The brake is released by pressurizing the spring actuator.