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Back Wire Rope Attachments | Up Builder 3&2 Volume 01 - Construction manual for building structures | Next Block and Tackle |
lead enough of it back through the socket to allow a
minimum of 6 to 9 inches of the bitter end to extend
below the socket. Next, replace the wedge, and haul
on the bitter end of the wire rope until the bight closes
around the wedge, as shown in figure 4-15. A strain
on the standing part will tighten the wedge. You need
at least 6 to 9 inches on the dead end (the end of the
line that doesnt carry the load). Finally, place one
wire rope clip on the dead end to keep it from
accidentally slipping back through the wedge socket.
The clip should be approximately 3 inches from the
socket. Use one size smaller clip than normal so that
the threads on the U-bolt are only long enough to
clamp tightly on one strand of wire rope. The other
alternative is to use the normal size clip and hop the
dead end back as shown in figure 4-15. Never attach
the clip to the live end of the wire rope.
The advantage of the wedge socket is that it is
easy to remove; just take off the wire clip and drive
out the wedge. The disadvantage of the wedge socket
is that it reduces the strength of wire rope by about 30
percent. Of course, reduced strength means less safe
working load.
To make an eye in the end of a wire rope, use new
wire rope clips, like those shown in figure 4-16. The
U-shaped part of the clip with the threaded ends is
called the U-bolt; the other part is called the saddle.
The saddle is stamped with the diameter of the wire
rope that the clip will fit. Always place a clip with the
U-bolt on the bitter end, not on the standing part of the
wire rope.
If clips are attached incorrectly, the
standing part (live end) of the wire rope will be
distorted or have mashed spots. An easy way to
remember is never saddle a dead horse.
You also need to determine the correct number of
clips to use and the correct spacing. Here are two
simple formulas.
3
6
x wire rope diameter + 1 = number of clips
x wire rope diameter = spacing between clips
Figure 4-15.Wedge socket attached properly.
Figure 4-16.Wire rope clips.
Another type of wire rope clip is the twin-base
clip (sometimes referred to as the universal or
two-clamp) shown in figure 4-17. Since both parts
of this clip are shaped to fit the wire rope, correct
installation is almost certain.
This considerably
reduces potential damage to the rope. The twin-base
clip also allows for a clean 360° swing with the
wrench when the nuts are being tightened. When an
eye is made in a wire rope, a metal fitting (called a
thimble) is usually placed in the eye, as shown in
figure 4-16, to protect the eye against were. Clipped
eyes with thimbles hold approximately 80 percent of
the wire rope strength.
After the eye made with clips has been strained,
the nuts on the clips must be retightened. Occasional
checks should be made for tightness or damage to the
rope caused by the clips.
Figure 4-17.Twin-base wire clip.
4-11
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