PRONAR PT512 Operator's Manual page 57

CHAPTER 3 Pronar PT512
The main pneumatic brake is activated from the tractor driver's cab by pressing the brake
pedal. The function of a control valve (2) – figures (3.5) and (3.6) – is to operate the trailer
brakes simultaneously with the tractor brakes. Furthermore, in case of an incidental
disconnection of the line between the trailer and a tractor, the control valve will automatically
activate the trailer's brake. The valve used is equipped with a circuit causing the brake to
release. It can be used when the trailer is disconnected from a tractor – see figure (3.7). After
the air line is connected to a tractor, the releasing device is automatically set in a way
enabling the normal brake operation.
A three step brake force regulator (2) – figure (3.7) – adjusts the braking force depending on
the setting. Switching to a suitable working mode is done manually by the operator before
driving off, by means of the lever (4). Three working positions are available: A – "no load", B
– "half loaded", C – "full load".
FIGURE 3.7 Control valve and brake force regulator
(1) control valve, (2) brake force regulator, (3) trailer parking brake release button,
(4) regulator working mode selection lever, (A) position "NO LOAD", (B) position "HALF
LOADED", (C) position "FULL LOAD".
3.11