National Crane 600H Service Manual Download Page 87

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NATIONAL CRANE

08-19-2022 Control # 092-13

4-13

600H SERVICE MANUAL

BOOM

Boom Disassembly Alternative #2

The boom design allows for removal of the extend cylinder
from the rear of the boom without complete disassembly of
the boom sections. This procedure allows quick access to
the cylinder, retract cables, and various internal boom
components for service or replacement. If this procedure is
used for disassembly, reverse procedure for reassembly, or
locate the appropriate step in the assembly procedure in this
manual to start reassembly from.

Remove hoist.

Gaining access through rear of boom, loosen and
remove capscrews retaining the extend cable anchor in
the rear of the 4

section as well as the anti-two-block

wire clamp on the anchor assembly. Loosen and remove
two capscrews retaining lock bar to extend cylinder.
Remove lock bar

Loosen and remove the nuts which secure the extend
cables to the extend cable anchor in the back of the
second section, remove capscrews from keeper plates
holding extend anchor in place, remove keepers.
Remove anchor. Remove nut from anti-two-block spade
bolt.

Drape extend cables and anti-two-block wire in side
boom, and slide cable anchor plate out of the side of the
hoist mount.

Loosen and remove two capscrews, lockwashers and
spacers which anchor the extend cylinder rod butt plate
to the rear of the 1

section.

Using appropriate lifting device, lift extend cylinder up
and out of retaining slots on rear of 2

and 3

sections.

Retracting cylinder with an external hydraulic power
source during this step may be necessary.

Pull cylinder out through rear of boom assembly
approximately one-half the length of the cylinder.
Turning of the butt plate and rod 90 degrees may aid in
sliding cylinder through hoist mount area. Keep extend
cables tight to minimize the possibility of damage.

FOUR SECTION BOOM ASSEMBLY

NOTE:

Do not use Loctite on any cable threaded ends.
Always use the locknut and nut provided.

When initially assembling threaded ends of cables, thread
the first on past the flat in the cables so adjustment can be
made later.

Assemble sheaves into 4

section sheave case. Top

sheave is to be installed to the left hand side of the boom
with the spacer to the right hand side.

Attach rear wear pads on bottom of 4

section. Using

Loctite 243 blue, Loctite all wear pad mounting
capscrews.

Install 4

section boom into 3

section. Slide together

approximately 5 ft (150 cm).

Assemble bottom front wear pads for 3

section and

Teflon plugs. Attach pads to pad plate.

Using appropriate lifting device, lift 4

section to allow

for wear pad/pad plate installation in front of 3

. Install

wear pad/pad plate assembly. Slide sections together
within 12 in (30 cm) of full retraction.

Install cable guide and upper spacer to front of 3

section

Install front side wear pads with appropriate shims,
between 4

and 3

sections. If boom has been

disassembled, and no sections have been replaced, use
same shim quantity and location as was previously
used. If locations are in question, refer to shim
calibration section in this book. Slide boom sections
completely together.

Assemble top rear wear pads to the top of the 4

boom

section. Wear pads can be inserted from the hoist mount
end of the boom, and the cam plates dropped through
the holes in the aligned boom top plates.

The wear pad on each side at the top/rear of the boom
can be adjusted over a range of 3/16in (4.8 mm) by
rotating, end for end, the wear pad and plate or the wear
pads and plate independently. This is possible because
the holes in these parts are offset from the center. The
holes are 0.06in (1.5 mm) off center in the plate and
0.03 in (0.8 mm) off center in the wear pad. Various
combinations of rotation of these parts allow the
adjustment.

Adjust pads until they are within 0.03” (0.8mm) off
center in the wear pad. Various combinations of
rotation of these parts allows the adjustment.

Torque retainer capscrews, refer to Fasteners and
Torque Values pg 1-7. Failure to properly torque
capscrews will cause loss of preload and cause
excessive side clearance between sections.

Uncoil 4/3/2 retract cable assemblies, and insert button
end into anchors in back of the 4

section. Place

uncoiled cable in area that will minimize the potential for
damage.

10.

Uncoil 1/2/3 retract cable assemblies, and insert button
end into cable anchor pockets in back of the 3

section.

Place uncoiled cable in area that will minimize the

WARNING

Do not, under any circumstances, work at an elevated
height without using proper fall protection as required by
local, state or federal regulations

REFERENCE ONLY