Maeda MC815C - Inspection of Slewing Ring Mounting Bolt

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[7] INSPECTION OF SLEWING RING MOUNTING
BOLT
• If any loose mounting bolt on the slewing ring breaks off, the upper part of the crane
comes off and falls, causing serious injury. Remember to check the slewing ring
mounting bolt and re-tighten with the specified tightening torque if any loose bolts are
found.
• Remember to replace the slewing ring mounting bolt regularly. Replace them every
seven years or every 7000 hours, whichever comes first.
★ Tightening torque of slewing ring mounting bolt
No.
Mounting
position
Dimension
Number
of bolt
to be used
Tightening
torque
(1)
Bearing inner
ring side
M22 31
612–828
N•m
(2)
Bearing outer
ring side
M22 15
612–828
N•m
Check the inner ring mounting bolt (2) following the
procedure below.
1. Remove the mounting bolts (4) (2 bolts) and then
remove the inspection cover (3) on the right of rotating
post.
2. Rotate the post so that the mounting bolt (2) on the
bearing inner ring side comes to the center of the
inspection opening (A) and check all the mounting bolts
(2) for loosening, loss or damage.
3. If any loose bolts are found, re-tighten with the
tightening torque in the above table. If any damages are
found, replace it with a new one.
4. After the inspection, reinstall the inspection cover (3) to
the original position.
Check the outer ring mounting bolt (1) following the
procedure below.
1. Rotate the post so that the mounting bolt (1) on the
bearing outer ring side comes to the side of machine
body and check all the mounting bolts (1) for loosening,
loss or damage.
2. If any loose bolts are found, re-tighten with the
tightening torque in the above table. If any damages are
found, replace it with a new one.