Terex Genie GTH-4017 EX Service Manual page 7

November 2008 Description
DESCRIPTION
A one-way valve calibrated at 8 bar (33), is installed
parallel to the input line of the heat exchanger and used
as safety valve. Its function is to avoid overpressure
conditions of the heat exchanger (as is the case of
a machine starting at low temperatures) by directly
draining any excess oil into the tank. The oscillation of
the rear axle of the machine is controlled by a block
cylinder (35) whose two chambers are equipped with
sealed 2-way/2-position solenoid valves. When the two
solenoid valves (46) are de-energised, the circular and
annular chambers of the cylinder are closed toward the
outside and the cylinder behaves like a strut/ tie-rod
blocking in this way the rear axle.
This happens when the inclination of the telescopic
boom exceeds a certain pre-set value of about 50° and
the side stability of the machine must be improved.
When, on the contrary, the boom inclination is below
such pre-set value, the two solenoids of the solenoid
valves are energised thus letting the oil circulating freely
from/to the two chambers of the cylinder. In this way,
the axle can oscillate, thus making the machine drive
more comfortable even in case of rough terrains.
The chambers of the cylinder are always kept filled with
oil by a single hydraulic line connected to the housing of
the drive pump (2).
This allows to have a minimum pressure capable of
keeping the circuit of the rear axle block cylinder full of
oil but incapable of producing overloads on the same
axle.
The ON/OFF type modular main valve (28) controls the
outriggers using the cylinders (24) (29) and controls the
levelling of the frame (30). In the input head of the main
valve there is a pressure relief valve set at 220 bar. The
oil flow that the main valve doesn't use, goes to the 20
cm gears hydraulic engine (7). The engine housing is
equipped with an anti-cavitation valve and a pressure
reducing valve set at 140 bar with by-pass function.
The outriggers and levelling cylinders are equipped
with a double-acting balancing valve (47) with safety
function.
When the machine is equipped with man-platform, a
battery-powered emergency pump (36) is installed to
be used in an emergency when the main circuit of the
telescopic boom is faulty.
To work correctly, this circuit uses one-way valves (37)
with different opening pressures.
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GTH-4017EX GTH-4514EX GTH 4013EX
Document 57.0009.0427