B42.60-0276-12
Framework
1 Lever (handle)
2 Inlet valve seat
3 Discharge (exhaust)
4 Outlet valve seat
5 Exterior piston
6 Auxiliary circuit valve seat
7 Auxiliary circuit valve body
8 Inlet valve body
a Inlet chamber
b Outlet chamber
11 Inlet connection with supply pressure for the parking brake.
12 Inlet connection with supply pressure for releasing the parking brake on emergency
21 Outlet connection with command pressure for the parking brake
23 Outlet connection with command pressure to release the parking brake in emergencies
A Inlet chamber (11)
B Outlet chamber (21)
C Auxiliary circuit inlet chamber
D Auxiliary circuit outlet chamber
Operation
Note: The parking brake application is done with the depressurization of the accumulator springs.
The double circuit valve allows, on running position, the activation of the combined brake cylinders (releasing the accumulator springs) through simultaneous compressed air circuits and derived from independent circuits.
The auxiliary circuit, through connections 12 and 23, on running position, keeps the combined pressurized cylinders permanently keeping the brake mechanism released.
When activating the lever (1) to the applied brake position, the auxiliary circuit discharges the air, starting to work only the main circuit (through 11 and 21).
On the main circuit, the operation is equal to the one described at the one circuit valve (GF42.60-B-3006-01B).
In the entrance of the combined cylinders connection 12 a two way valve is installed to derive the pressures. In case of failure in one of the circuits, the other one works normally.
On the running position, the lever (1) is free and the communication valves of chambers A with B and D with E are open.
Applying the lever approximately 10°, the communication valve between D and E closes. Chamber E communicates with the atmosphere through discharge (3). From this point on, the main system starts operating normally to use the brake as auxiliary or as the vehicle's parking brake itself.
By gradually activating the lever (1), the main valve closes, preventing the communication between chambers A and B, the pressure in chamber B is progressively reduced as a consequence of the exit of compressed air from chamber B to the atmosphere and through the discharge valve (4), and from it to exhaustion (3).
Keeping the activation of the lever on the application direction, it reaches a more resistance point of approximately 67°. On this position, the intake valve (2) is closed and chamber B is in communication with the atmosphere; as a consequence, the total release of springs on the combined cylinders and the application of the “parking brake”.