21
6.4.7
PROPORTIONAL DUAL-MODE REGULATION HYDRAULIC UNIT
(Pict.12)
The unit is consisting of two separate aluminium blocks.
The upper section includes the proportional adjusting valve (
VR
), the manual bypass control valve (
OM
) of the
proportional regulator, the main relief valve (
VM
), the winch operating solenoid valves (
EV4A
–
EV4B
), the
dump valve (
EV9
) and the solenoid valves (
EV3
–
EV4
) required to operate the winch and another function at
the same time.
The lower section includes the control solenoid valves (
EV
…
A
–
EV
…
B
), two for each movement.
The solenoid valves:
EV9
–
EV3B
–
EV2B
–
EV1B
–
EV1A
are equipped with a manual override, to be used
only for emergency (failure of the electronic control unit or the button strip, lack of power supply).
In such cases it is necessary to proceed as fol-
lows:
a
)
Fully turn counter-clockwise the valve
handwheel (
OM
) in order to bypass the
proportional valve (
VR
)
b
)
Fully turn counter-clockwise the manual
override of the valve coupled to the
desired movement (extension re-entry,
boom lowering, etc.).
c
)
Finally Fully turn counter-clockwise the
manual override of the valve (
EV9
), in
order to activate the desired movement
d
)
Once the standard working conditions of
the crane are restored, always remember
to close completely the manual overrides,
by turning them clockwise.
e
)
Finally close completely the bypass valve
(
OM
) by turning the handwheel clockwise.
6.4.8
WIRING
(pict.13)
Made up of a single wiring unit that is
connected to the electronic unit through two
sealed multipolar connectors (
1
) provided with
quick hooking system.
The wiring includes the solenoids to connect
the solenoid valves located on the hydraulic
unit, it also connects the unit to the safety limit
switches (
FA
–
FB
–
FV
), to the pressure
gauge or to the pressure transducer (
PM
), to
the diesel engine start/stop and to the power
supply. The wiring also includes the keyboard
connection female connector (
3
) that is
placed aside the electronic unit on the crane’s
cover.
Pict.13
1
2
3
Pict.12
EV3A
EV9
VM
1
VR
EV4B
EV3B
EV2B
EV1B
EV3
OM
EV4
EV4A
EV2A
EV1A
