Frenos de Doble Pulmón
Funcionamiento del freno de doble función

DOUBLE FUNCTION: direct brake + safety brake.

The usual mode of operation is as a direct brake, with progressive braking depending on the pneumatic pressure applied, analogous to any conventional brake. At the same time, it is a safety brake, which activates the lock at the desired moment.

The double function is possible thanks to the inclusion of a double air chamber or double lung, with respective pneumatic injection valves.

In its direct brake mode, progressive braking is governed by the greater or lesser pneumatic pressure applied to the direct chamber. In safety braking, the negative chamber is depressurized, causing the spring to decompress, which pushes the stem that activates the braking.

Double chamber brakes are common in special vehicles that need to control the braking torque and have, at the same time, a safety system, all occupying the minimum space.

 

 

DIRECT BRAKE MODE. Usual mode of operation

When both chambers are pressurized, the brake operates dynamically.

Keeping the negative chamber pressurized -constant pressure-, the spring remains compressed and does not act on the stem.

Progressive braking is achieved by controlling the pneumatic pressure delivered to the direct chamber -between 0 and 7 bars-. This pressure will govern the displacement of the stem, which will actuate the jaw with a force proportional to the applied pneumatic pressure.

+ direct cam valve pressure => + braking force

 

 

SAFETY BRAKE APPLIED

The locking action is triggered when the safety chamber is depressurized, its internal spring displaces the stem and braking is complete.

 

 

NEGATIVE BRAKE OFF. Brake released.

If pneumatic pressure is applied to the negative chamber (compressed spring) and the threshold pressure is not applied to the direct chamber valve, the brake is released (unbraked).