Document 57.4402.8200 - 1
st
Edition 03/2007
INDEX
GYRO 4020 - 4518
INTRODUCTION
v
circuit cannot do it alone.
The control module of element 3 of the main valve is the
electro-proportional type with electrical feed-back and
integrated electronics.
On the two control lines of the cylinder (
17
), and integral
to module 3, there are two pressure relief valves set to
320 bar which protect the automatic levelling system of
the forks when the boom is moved up and down and in
case of overload on the attachment holding plate (ex.
use of the bucket).
Module 4 of the main valve controls the attachment
locking cylinder (
23
). This cylinder has a double one-
way valve with hydraulic release, acting as safety valve
(
24
). The pilot module of element n. 4 of the main valve
is the electroproportional type with integrated electric
and electronic feedback.
On one of the two hydraulic control lines of this section
of the main valve, there is a 3-way/2-position electric
divider with on/off control (
22
).
When this divider is not energised, the oil at pressure
coming from the module of the main valve, is sent to
the attachment locking cylinder. On the contrary, when
the divider (
22
) is energised, the oil at pressure from
element n.4 of the main valve (
8
), is made available for
the auxiliary feeding line of the turntable lock/unlock
function and, through port n. 3 of the hydraulic rotary
joint (
9
), for the operation of the outriggers and the
frame levelling.
On the feeding lines of this cylinder and close to the
terminal part of the end trunk, there are two quick-fit
connectors (
25
) for the connection of the hydraulic lines
of any optional equipment needing a hydraulic power
for their operation (e.g. hydraulic winch and jib, mixing
bucket, etc.).
Module n. 5 of the main valve controls the hydraulic
slewing motor of the turntable (
26
), equipped with brake
with internal mechanical block and external hydraulic
release. The mechanical torque produced by this motor
is transmitted to the turntable through an epicyclic
reduction gear with two stages and a slewring with
internal toothing.
The feeding line of this motor is equipped with a double-
acting compensation valve (
27
), used also as safety
and anti-cavitation valve.
The pilot module of this element of the main valve is
of electroproportional type with integrated electric and
electronic feedback.
Inside this module of the main valve, there is a two-way
pressure compensator which keeps the proportionality
of the slewing control of the turntable as the loads on this
table and the pressure entering the main valve modules
change. The pressure of the main valve is adjusted by
the three-way compensator placed on the inlet head.
The main valve (
8
) is equipped with a pilot line of the
“load sensing” type which, through the exchange valve
(
10
), is connected to the priority valve (
6
), which, at
