© Feb. 2023
56 TB20J Plus Maintenance Manual
BOOM AND PLATFORM ASSEMBLY
2. Measure the thickness of each slider at the head
and tail of the main boom.
3. If the telescopic cylinder has sliders, measure the
slider thickness after the telescopic cylinder is
removed.
4. Compare the measured thickness value of each
slider with the value specified in the above table,
and replace the slider assembly in time if the wear
extent of the slider is greater than or equal to 3mm
(0.118in).
NOTICE
The disassembled slider cannot be reused and must
be replaced with a new slider assembly.
Telescopic Wire Rope
When extending/retracting the boom tube, all
boom segments should extend/retract together at
the same speed. In case of any abnormality, there
may be a delay in movement and loose wire
ropes. Before using the machine each time,
extend/retract each boom segment. If there is any
abnormality, immediately lower the platform to
the stowed position, turn off the machine, and
have the wire rope inspected and repaired by
qualified service technicians.
NOTICE
The telescopic wire ropes have sharp edges, and
touching the wire ropes with bare hands can cause
serious injury.
Check wire ropes and pulleys
The telescopic wire ropes are used to extend and retract
the boom tube. In order to ensure that the boom extend-
ing and retracting are smooth, without shaking and ab-
normal noise, it is recommended to check the wire
ropes and pulleys every quarter or after 250 hours of
operation.
1. Remove the cover at the boom tail.
2. Perform the following checks on the wire rope:
• Check the rope for wear, breakage, corrosion or
entanglement, and check the pulley for exces-
sive wear or damage. Replace the wire rope and
pulley if necessary.
Note: The wire rope and pulley must be re-
placed together. Before installing the wire rope,
the wire rope needs to be lubricated.
• Check the wire rope pulley bearing for wear,
scratches or damage. Replace the bearing if
necessary.
• Check the wire rope for foreign debris. If any,
clean it up immediately.
• Check the relative position between the wire
rope and pulley. If the wire rope is outside the
pulley, adjust the wire rope to the correct
position.
• Manually deflect the wire rope to check the ten-
sion of the wire rope. Appropriately tensioned
wire ropes should be unable or difficult to move.
If the wire rope is inappropriately tensioned, ad-
just it according to the method below.
3. After checking and making sure there are no prob-
lems, install the cover to the boom tail.
4. Start the machine from the ground controller and ex-
tend the boom approximately 0.6m (2ft).
5. Retract the boom tube and check the movement of
the 2nd and 3rd boom segments. The retraction dis-
placement of the 2nd boom segment should not ex-
ceed 1/2 of that of the 3rd boom segment.
Adjust the tension of wire rope
1. Adjust the boom to horizontal and extend it 1.5-
1.8m (5ft-6ft).
2. Remove the locking nut from the wire rope fixture.
3. As shown in the figure below, clamp the threaded
end (platform end) of the retracting wire rope with a
tool to prevent rotation.
Fig 8
NOTICE
Do not clamp the threads.
4. Install the adjusting nut on the retracting wire rope.
5. Using a wrench, alternately tighten the adjusting
nuts on the two retracting wire ropes to the torque in
the Torque Specifications of the manual.
6. Retract the boom to the extended length of 0.6-
0.9m (2ft-3ft).
7. Clamp the threaded end (turntable end) of the
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