B42.60-0277-03
Structure
1 Lever (fist)
2 Cam
3 Discharge (exhaustion)
4 Spring
5 Piston rod
6 Scaling piston
7 Valve
8 Valve
9 Rod
11 Inlet connection with supply pressure to activate parking brake.
12 Inlet connection with supply pressure for emergency release of parking brake
21 Exit connection with command pressure to the parking brake
23 Exit connection with command pressure for emergency release of parking brake
Operation
Note: Activation of the parking brake is done through depressurization of accumulator springs.
I - Driving position:
With lever (1) at the deactivated brake position, the service pressure enters through the connection (11), goes through the air flow (b) and flows through connection (21), into the circuit of the parking brake.
Simultaneously, the compressed air used for the emergency release enters through the connection (12), goes through the air flow (d) and flows through connection (23), into the circuit of the parking brake.
II - Progressive braking position:
By activating the lever (1) towards the arrow (A) the piston rod (5) moves together with the valve (7) upwards, sliding in the cam section (2). Equally, the rod (9), also moves upwards together with the valve (8) against the cam jamb (2).
After an activation angle of approximately 4°, the air flow (d) will close and the exit (c) will open. The air inside the connection circuit (23) will be discharged into the atmosphere through connection (3).
After an activation angle of approximately 10°, the air flow (b) will close. This is the balance point of the valve.
From this point the air release (a) opens, allowing to lower the air pressure in the connection circuit (21). Then, as the air pressure is higher in the connection (11) the piston (6) will be moved upwards, against the action of the spring (4). With this the valve (7) will also move upwards until a new balance position.
Following this sequence, the connection circuit (21) will be progressively depressurized until the connection pressure (11) is no longer able to move the piston (6) against the spring (4).
From this point the piston rod (5) continues moving up, opening the air release (a) and depressurizing completely the connection circuit (21).
III - Complete braking position:
By activating the lever at approximately 67°, there will be a high resistance to its movement, which must be overcome by the application of the total activation of the parking brake.
At an angle of approximately 73°, the lever (1) will lock automatically. At this position the cumulating springs are totally depressurized.
To release the parking brake, pull the lever (1) about 3 mm towards the arrow (B), after which it will return to its initial position.
In case there is a failure in the circuit of the parking brake, there will be no pressure at the connection (11). In that case the valve will automatically make the emergency release through the release of the connection air (12) into the connection (23) and then command the depressurization of the cumulating springs.