2.5 Clearance adjustment at upper part
of the boom head
(section [4] indicated in Figure 1)
1. Extend the inner boom section for approximately
0.5 m (1.64 ft). Next, lift the boom head slightly to
an extent that the inner case to be adjusted does
not rise up, and then adjust the clearance.
[NOTICE]
If the boom section is not lifted for the work, the tilt
cannot be followed to the boom bottom side, and
the bottom becomes twisted against the head, and
the adjustment of section [5] cannot be performed
correctly.
2. Set the slide plates along the curve of the inner
boom section without inclination, and then turn the
upper-side adjustment bolts to let the slide plate to
touch the retainer.
[NOTICE]
If the boom is assembled without correcting the
tilting of the slide plates, a load can move the slide
plates, and the fixing of the retainer may become
loose.
3. Adjust the dimension A using the side adjustment
bolts so that the left-side dimension becomes 1
mm (0.04 in) greater than that in the right side.
[Example: Dimension (left) = 21 mm (0.83 in),
Dimension (right) = 20 mm (0.79 in)]
The above completes the adjustments of 3rd - 5th
boom sections.
For the base boom and 2nd boom sections only,
perform the adjustment described in 4 and 5 below.
4. After the above adjustment, retighten the upper
and side adjusting bolts for 1/4 turns, and then fix
them using nuts (in both sides).
5. Lastly, tighten the fixing bolt to the tightening
torque of 36 to 40 N-m {370 to 410 kgf-cm} (27 to
30 ft-lbf), then bend the washer plate to stop the
bolt from turning. (If the washer plate does not
come to the appropriate position at the specified
torque, position the washer plate to the tightening
direction.)
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