PRONAR T663/1 Operator's Manual page 57

SECTION 3 Pronar T663/1 T663/1 SILO
The main brake (pneumatic or hydraulic brake) is activated from the tractor driver's cab by
depressing the brake pedal. The function of the control valve (2) - figure (3.6), (3.7) and (3.8)
is to activate the trailer's brakes simultaneously with the tractor's brakes. Furthermore, in
case of an inadvertent disconnection of the conduit between the trailer and the tractor, the
control valve will automatically activate the trailer's brakes. The valve used in the system is
equipped with a circuit causing the brakes to be applied when the trailer is disconnected from
the tractor, compare figure (3.10). When compressed air conduit is connected to the tractor,
the device automatically applying the brakes now changes its position to allow normal brake
operation.
FIGURE 3.9 Design and diagram of hydraulic braking system
(1) hydraulic cylinder, (2) hydraulic quick coupler, (3) hydraulic socket, (4) information decal
Three-step braking force regulator (2)- figure (3.10), adjusts braking force depending on
setting. Switching to a suitable working mode is done manually by the machine operator
using the lever (4) prior to moving off. Three working positions are available: A - "no load", B -
"half load" and C - "full load".
3.13