Manitowoc National Crane NBT40 Series, Service Manual

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BOOM MAINTENANCE NBT40 SERVICE MANUAL
4-46
Published 8-01-2017 Control # 287-11
supported by the jib ears. The jib will typically rest only
on the upper support, Figure 4-28.
7. Observe the horizontal alignment of the slot in the ear
assemblies and the stow pin in the jib. Horizontal
adjustment of the stow ears is provided by oversize bolt
holes in the stow ear. Move the ears in or out to achieve
proper alignment. Position the top ear so it holds the top
of the jib in toward the boom and the bottom ear so that it
holds the bottom of the jib away from the bottom of the
boom, see Figure 4-29.
8. Retract the boom slowly. Observe the stow hook and
lock assembly alignment as the boom is retracted,
Figure 4-30.
9. When the boom is fully retracted, the jib stow pins must
be bottomed out securely in the ear assemblies,
Figure 4-31.
If the stow pins are not aligned properly, the hook
assembly and front bars will have to be positioned as
shown so the jib cannot slide forward or backward as the
boom is elevated.
10. Try to remove the jib pins. If the pins are too tight, the
stow hook assembly or front bars will have to be
adjusted.
11. Torque all capscrews to their specified torque value (see
table in Service and Maintenance Section). Install stow
pin in lock assembly and remove the jib pins.
12. Extend and retract boom to insure proper alignment of
jib pins.
13. Install jib pins and remove the stow pins.
JIB
EARS
BOOM
UPPER
SUPPORT
BOOM LOWER
SUPPORT
SHIMS
FIGURE 4-28
STOW PIN
FIGURE 4-29
CAUTION
Make sure the ramp slides up the stow hook and does
not hit the end of the ramp
STOW HOOK
ON BOOM
RAMP ON JIB
STOW PIN
FIGURE 4-30
STOW PIN
BOTTOMED
IN SLOT
FRONT BAR (TOP
and BOTTOM)
NOT
ACCEPTABLE
ACCEPTABLE
HOOK ASSY
T-PIN
FIGURE 4-31
Reference Only