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November 2008
DESCRIPTION OF THE MACHINE OPERATION
GTH-4017 EX - GTH-4514 EX
The mechanical energy source of these machines is a
(1) Perkins diesel engine model 1104/d-44T, which
supplies a 74,5 kW at 2300 rev/min with a max torque
of 392 Nm at 1400 rev/min.
On the flywheel side of the engine, and connected to the
same by a Technodrive coupler complete with elastic joint
and with a 1-to-1 ratio, there is Sauer danfoss closedloop
pump for hydrostatic drives, model H1P078 (2). Max
displacement of this swashplate pump is 78 cm
the max calibration pressure is 450 bar. This pump is used
to supply hydraulic power under form of pressure and flow
rate which is then used for moving the machine. On the
through-shaft of such drive pump there is a Casappa open-
loop gear pump (with fixed displacement) (3) with priority
valve integrated in the housing. The displacement of this
pump is 43 cm
/rev. Its function is to provide hydraulic
3
power, under form of pressure and flow rate, to the steering
circuit of the machine (primary side) and to the circuit for
the telescopic boom movements (secondary side). The
assembly of the two pumps involves they have a rotation
velocity equal to the speed of the diesel engine. A third
Casappa open-loop gear pump (with fixed displacement)
(4) with a displacement of 20 cm
PTO of the engine located to the distribution side. This
pump feeds the servo-assisted braking system (25). The
suction lines of the open-loop pumps (3) and (4) are
protected by an immersed filter (8), placed inside the
hydraulic fluid tank (10) whose capacity is 150 litres. Just
upstream of the connection with the three suction lines
mentioned above, there is a gate valve with ball valve
(9) which lets you cut out the hydraulic oil tank in order
to perform maintenance interventions on the machine's
hydraulic system. The drive pump (2) is protected by a
special filter (34), placed on the external side of the tank
and protected by a gate (40).
The one-way valve (11) set at 2.5 bar protects the
pump housing against high pressures and guarantees a
certain circulation of the drain oil to the hydrostatic motor
reducing, in this way, the temperature. From port "M3" of
the drive pump (2) low-pressure oil is taken (25-30 bar)
and used for the anti-cavitation circuit of the automatic
fork levelling system. The hydraulic energy produced by
the drive pump (2) is converted into mechanical power by
a closed-loop hydrostatic motor, Sauer danfoos 51D110
model (5). The max displacement of this bent-axis motor
is 80 cm
/rev.
3
Document
57.0009.0427
/rev, and
3
/rev., is installed on the
3
GTH-4017EX GTH-4514EX GTH 4013EX
The motor is directly flanged to the Dana single-speed
reduction gear (26), which is fixed with brackets to the
central zone of the chassis. The mechanical torque at
the gearbox output is transmitted to the front axle (6)
and the rear axle (27), both model 212 manufactured by
Dana, through Cardan shafts. The hydraulic drive (12)
of "load sensing" type with a displacement of 315 cm
rev., receives oil from the priority line of the pump (3) in
relation to the "load sensing" signal sent by the hydraulic
drive and connected to such pump with function of pilot
signal. In this way, the input flow to the hydraulic drive
is exactly the one needed for the instantaneous steering
functions; any excess flow of the pump is available for
the functions of the telescopic boom. The steering circuit
is protected against input overpressures by a pressure
reducing valve set at 140 bar. On the two delivery lines
to the steering cylinders there are other two pressure
reducing valves with anti-shock function set at 200 bar.
These two valves are intended to limit possible shocks
on the steering wheel due to overstress on the steering
cylinders. The pressure reducing valves are installed in
the hydraulic drive (12) and cannot be regulated from
the outside. The steering circuit is completed by the
front steering cylinder (14), the rear steering cylinder
(15) (these cylinders being integral part of the front
axle (6) and the rear axle (27) respectively) and by a
4-way/3-position solenoid valve (13) for the selection of
the three different steer modes (rear wheels straight,
co-ordinate front/rear steering and independent front/
rear steering).
When the solenoid valve (13) is not energised, the
hydraulic drive supplies power to the front steering
cylinder; the rear steering cylinder is locked. When
one magnet or the other of the solenoid valve (13) is
energised, the chambers of the cylinders are connected
in a different manner thus causing the desired effect on
the steering mode. The Walvoil 4-section valve block of
mechanical type (16) receives oil from the secondary
line of the pump (3) and feeds all the movements of the
telescopic boom.
This valve consists of an input head with 3-way
pressure compensator used as a flow regulator for the
user which works at max load (load sensing), and as
a discharge valve when the pump flow is not used for
the boom movements, and of 4 modules each one of
them controlling a specific function of the telescopic
boom, that is lifting/lowering, attachment holding plate
Description
Description
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3
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