TM 5-3810-307-24-1-1
BOOM EXTENSION AND RETRACTION CABLES
MAINTENANCE
INSPECTION.
ADJUSTMENT.
WARNING
NOTE
Never handle wire rope with bare hands.
The retraction cable must be adjusted
before the extension cables.
The following information is taken from a National
Consensus standard as referenced by Federal
1.
Extend and set the outriggers, ensuring the
Government Agencies.
crane is level.
All wire rope will eventually deteriorate to a point
2.
Ensure the boom is over the front and at a
where it is no longer usable. Wire rope shall be taken
horizontal position (boom angle elevation 0 degrees).
out of service when any of the following conditions
exist.
3.
Extend the boom sections approximately one
foot (20.5 cm).
1.
In running ropes, six randomly distributed
broken wires in one lay or three broken wires in one
4.
Loosen the extension cables by loosening the
strand in one lay.
jam nuts and locknuts. Do not remove the nuts.
2.
Wear of the original diameter of outside
5.
Retract the boom sections slowly until the mid
individual wires. Kinking, crushing, bird caging, or
and fly sections bottom out and note the point at
any other damage resulting in distortion of the rope
which the mid and fly sections bottom out. The stop
structure.
block on the bottom of the fly section bottom plate
should make contact with the mid section bottom
3.
Evidence of any heat damage from any cause.
plate approximately 0.125 to 0.375 in. (0.31 to 0.95
cm) before the stop block or the bottom of the mid
4.
Reductions from nominal diameter of more
section contacts the base section bottom plate.
than:
NOTE
0.016 in. (0.4 mm) for diameters up to and
including 0.3125 in. (8 mm)
If the fly section bottoms out too early,
0.031 in. (0.79 mm) for diameters 0.375 and
the retraction cable is too tight and must
0.5 in. (10 and 13 mm) inclusive.
be loosened. If the fly section bottoms
0.047 in. (1.19 mm) for diameters 0.5625 to
out too late, or fails to bottom out, the
0.75 in. (14 to 19 mm) inclusive.
retraction cable is too loose and must be
0.063 in. (1.59 mm) for diameters 0.875 to
tightened.
1.125 in. (22 to 29 mm) inclusive.
0.094 in. (2.38 mm) for diameters 1.25 to 1.5
6.
Adjust the retraction cable adjusting nut and
in. (32 to 38 mm) inclusive.
jam nut on the left side of the base section until the
dimension outlined in step 5 if achieved.
5.
In standing ropes, more than two broken wires
in one lay in sections beyond end connections or
7.
Fully extend the boom, slowly. Fully retract the
more than one broken wire at an end connection.
boom and check that the stop block on the bottom of
the fly section has bottomed against the mid section
bottom plate. If contact has not been made, repeat
step 6.
