NATIONAL CRANE
Published 03-23-2018 Control # 243-14
4-15
NBT50 OPERATOR MANUAL
SET-UP
4
Wedge Socket Installation
1.
Inspect the wedge and socket. Remove any rough
edges and burrs.
2.
The end of the wire rope should be seized using soft, or
annealed wire or strand. If the end of the rope is welded,
the welded end should be cut off. Do not weld on size
6X37 rope. This will allow the distortion of the rope
strands, caused by the bend around the wedge, to
adjust themselves at the end of the line. Refer to
SECTION 1 - INTRODUCTION in the Service Manual
for wire rope procedures.
3.
Make sure the live-end (Figure 4-9) of the rope is directly
in line with the lugs of the socket and the direction of pull
to which the rope will be subjected. If the rope is loaded
into the socket incorrectly, under a load the rope will
bend as it leaves the socket, and the edge of the socket
will wear into the rope causing damage to the rope and
eventual failure.
.
4.
Insert the end of the wire rope into the socket, form a
loop in the rope, and route the rope back through the
socket allowing the dead-end (Figure 4-9) to protrude
from the socket. Ensure the dead-end of the rope is of
sufficient length to apply end treatment to the dead-end
after the wedge has been seated.
5.
Insert the wedge into the loop and pull the live-end of the
rope until the wedge and rope are snug inside the
socket. It is recommended that the wedge be seated
inside the socket to properly secure the wire rope by
using the crane’s hoist to first apply a light load to the
live-end.
6.
After final pin connections are made, increase the loads
gradually until the wedge is properly seated.
7.
The wire rope and wedge must be properly secured
inside the socket before placing the crane into lifting
service. It is the wedge that secures the wire rope inside
the socket. The dead-end treatment is used to restrain
the wedge from becoming dislodged from the socket
should the rope suddenly become unloaded due to the
headache ball or hook block striking the ground, etc.
Sketches A through F (Figure 4-10) illustrate various ANSI
approved methods for treating the dead-ends of wire ropes
which exit a wedge socket assembly. While use of the loop-
back method is acceptable, care must be exercised to avoid
the loop becoming entangled with tree branches and other
components during crane transport and with the A2B system
and other components during use of the crane.
Of the methods shown below, Manitowoc prefers that
method A or F be used, i.e., clipping a short piece of wire
rope to the dead-end or using a commercially available
specialty wedge. Typically, it is recommended that the tail
length of the dead-end should be a minimum of 6 rope
diameters but not less than 6 in (15.2 cm) for standard 6 to 8
strand ropes and 20 rope diameters but not less than 6 in
(15.2 cm) for rotation resistant wire ropes.
When using method A, place a wire rope clip around the
dead end by clamping a short extra piece of rope to the rope
dead end. DO NOT CLAMP THE LIVE END. The U-bolt
should bear against the dead end. The saddle of the clip
should bear against the short extra piece. Torque the U-bolts
according to the table titled Wire Rope Clip Torque Values
(Table 4-1).
Other sources for information with which crane users should
be familiar and follow is provided by the American Society of
Mechanical Engineers, American National Standard, ASME
B30.5, latest revised. ASME (formerly ANSI) B30.5 applies
to cableways, cranes, derricks, hoists, hooks, jacks, and
slings. It states, in section 5-1.7.3, “(c) Swagged,
compressed, or wedge socket fittings shall be applied as
recommended by the rope, crane or fitting manufacturer.”
Wire ropes are addressed in ASME B30.5, section 5-1.7.2,
ROPES, it states, in pertinent part, “(a) The ropes shall be of
a construction recommended by the rope or crane
manufacturer, or person qualified for that service.” Additional
information is published by the Wire Rope Technical Board in
the Wire Rope Users Manual, latest revised edition.
Dead
End
Dead
End
Live End is
Entering
Wrong Side
Live
End
20 x Cable Dia
Minimum
RIGHT
WRONG
FIGURE 4-9
Wedge Socket
Summary of Contents for National Crane NBT50 Series
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