National Crane Published 03-18-2019 Control # 582-04 4-7
NBT30H-2 OPERATOR MANUAL SET-UP
5. Disconnect twist lock anti-two block wire connector at
rear of 1
st
section extension. Connect twist lock
connector to anti-two block switch connector on boom
tip. Move weight/chain assembly to boom tip.
6. Attach tag line to sheave case end of extension.
7. Remove spring clips from pins C2 on both upper and
lower extension ears.
8. Remove extension swing pin B from the boom nose.
9. Remove pins C2 from upper and lower extension ears.
Do not remove C1 pins at this time. C1 pins will be used
as a pivot point to swing extension into stow position. A
slight hammer strike may be necessary to remove pins.
Always use proper eye protection during this step.
10. Raise the boom to the horizontal position.
11. Extend boom approximately 0.3 m (1 ft).
12. Using tag line attached to extension sheave case, slowly
swing extension into stow position (parallel with 1
st
section boom), Pins C1 are the extension pivot points
during this operation.
:
13. Install extension swing pin B with spring clip through
extension ear and boom sheave case holes. This pin will
keep the extension assembly in line (parallel) with the I
st
boom section. Extension swing pin B does not retain the
extension in its stowed position on the I
st
boom section.
14. Using boom telescope function, slowly retract boom.
The ramp/side stow bracket assembly on the side of the
1
st
section extension will engage the hook on the side of
the 1
st
boom section, first lifting the extension and then
engaging the extension side stow bracket and the boom
hook completely upon full retraction of the boom.
15. Install stow pin A with spring clip into the ramp/side stow
bracket assembly on the extension. Complete
engagement of stow brackets and proper installation of
pin A is critical for secure extension stow attachment.
16. Remove pins C1 from upper and lower extension ears. A
slight hammer strike may be necessary to remove pins.
17. Reinstall loadline over boom sheave case.
:
EXTENSION REMOVAL
Should extension removal from the boom become
necessary, proceed as follows:
1. Unstow and swing extension into position on the boom
tip according to Steps 1 - 10 in the preceding
Deployment Procedure, page 4-4.
2. Support and raise the extension at its balance point with
a suitable lifting device and straps or chains.
3. Remove the two swing around pins. Extension is now
free of boom.
To install, proceed in reverse order of removal.
When the extension is stowed on side of crane, always leave
the ram and handle sleeve of the extension jack pushed all
the way down to reduce exposure to rusting.
Extension Maintenance
1. Lubricate as outlined in Lubrication Procedure and
Charts, page 5-1.
2. Check for free rotation of extension sheave daily when
using extension.
CAUTION
Equipment Damage Hazard!
Use caution when swinging extension to avoid
unnecessary impact with 1
st
boom section.
CAUTION
Eye Injury Hazard!
Use safety glasses when striking pins with a hammer.
DANGER
Crushing Hazard!
Visually check all pin positions and make sure the
extension is fully retracted into side stow brackets,
extension stow attachment is secure, and all pins and
spring clips are in their proper locations. Failure to
properly secure the extension during stowing and erecting
may allow the extension to fall. Serious personal injury or
death could result.
Always have at least one of the following in place at all
times:
• Side stow bracket completely engaged into stow
hook with stow pin A properly in place.
• Both pins C1 in upper and lower extension holes
properly in place through mating holes on boom tip.
CAUTION
The 44 ft extension weighs 1470 lb (667 kg) at 147 in (374
cm) when retracted from mounting pin holes.
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