National Crane 600H Service Manual Download Page 89

Page: 89 / 232

NATIONAL CRANE

08-19-2022 Control # 092-13

4-15

600H SERVICE MANUAL

BOOM

31.

Visually verify that the extend cables are properly routed
on their sheaves and continue to slide with the extend
cylinder and cables into the boom sections. Keep extend
cables supported and slightly tensioned during insertion
of cylinder to maintain proper cable placement.

32.

As the extend cylinder nears complete insertion into the
2

section assembly, adjust the height of the

cylinder to allow the cylinder anchor collars to access
the cylinder keeper cut outs in the doubler plates on the
sides of the 2

and 3

sections.

33.

Drop the cylinder down into the vertical cutouts in the
doubler plates on the sides of the 2

and 3

sections.

Cylinder length or boom section placement may have to
be adjusted to allow cylinder collars to drop into their
proper position.

34.

Install lock bar and capscrews to the extend cylinder
collar in the 3

section.

35.

Route 2/3/4 anti-two block cable segment through boom
sections (see Anti-Two- Block Installation section) and
attach accordingly.

36.

Install large extend cable anchor into anchor cut outs in
the doubler plates in the rear of the 2

by routing the 5/

8 in (15.88 mm) extend cables through the anchor and
the small 3/8 in (9.53 mm) cable over the anchor. Slide
anchor fully into cutout.

37.

Install keeper plates and hardware. This keeper plate
retains both the horizontal movement of the extend
anchor and the vertical movement of the extend cylinder.

38.

Anchor 2/3/4 anti-two-block cord in the extend anchor
(see Anti-Two-Block Installation section) using
appropriate hardware.

39.

Route 1/2 anti-two-block segment on the bottom of the
1

section boom (see Anti-Two-Block Internal Wire

System section).

40.

Install 2/3/4 section boom assembly into l

section

boom, use caution when sliding sections together, 3

retract cables must maintain their position to prevent
damage, do not let boom rest on cables. Damage will
result.

41.

Assemble bottom front wear pads for 1

section and

Teflon plugs.

42.

Using appropriate lifting device, lift 2/3/4 section
assembly to allow for wear pad installation in front of 1

Install wear pads. Slide sections together within 12 in (30
cm) of full retraction.

43.

Install upper spacer to front of 1

section.

44.

Install front side wear pads with appropriate shims
between 2

and 1

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.

45.

Push boom together until extend cylinder butt plate
makes contact with the rear cylinder anchor plates in the
rear of the 1

section. Install spacers, washers and

capscrews, attaching cylinder to 1

section boom. If

cylinder is misaligned with anchor points, cylinder butt
plate can be rotated to achieve proper alignment
(holding valve up, parallel with boom top plate).

46.

Assemble top rear wear pads to the top of the 2

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 3/16 in (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 0.06 in (1.5 mm) off center in the plate and
0.03 in (.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” (.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.

47.

Install thick hoist attachment bar through hoist mount.
This bar anchors the 3/8 in (9.53 mm) extend cable and
serves as the upper hoist attachment point. Hold this bar
up in its slot with a spacer on each side. This will
facilitate easier assembly.

48.

Install the threaded end of the 3/8 in (9.53 mm) extend
cable through hole in center of the hoist attachment bar.

49.

Slightly tighten all cables. Cycle boom slowly to assure
proper operation before torquing cables. Refer to the
Four Section Cable Tensioning section to properly
torque the cables in the extend system. Cables must be
torqued to proper specifications for proper boom
operation.

50.

Install hoist.

FOUR SECTION TOP/BOTTOM PAD
REPLACEMENT ASSEMBLED BOOM

Inspect top and bottom wear pads periodically for signs of
abrasion or excessive wear. Excessive is defined as 3/16 of
an in (4.76 mm) from the original pad thickness, top rear pad
thickness 0.75 in (19 mm), bottom front 1

section 1 in (25

mm), bottom front 2

and 3

section 0.44 in (13 mm).

REFERENCE ONLY