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Construction Electrician Basic - Electricity handbook for electricians | Next
Moving Materials and Equipment |
Figure 1-12.—Bridles.
on one end and a pelican hook on the other. There is also
available a 3/4-inch (19.05-mm) chain sling, 22 feet
(6.6 m) long, with a grab hook on one end and a Cinch
(100-mm) link on the other.
Before doing any lifting with a chain sling, first
place dunnage between the chain and the load to provide
a gripping surface. In handling rails or a number of
lengths of pipe, make a round turn and place the hook
around the chain as shown in figure 1-13.
In using chain slings, you must exercise care to
avoid twisting or kinking the chain while it is under
stress. This condition might cause failure of the chain,
even in handling a light load. Before lifting, make sure
that the chain is free from twists and kinks. Make sure,
also, that the load is properly seated in the hook (not on
the point) and that the chain is free from nicks or other
damage. Avoid sudden jerks in lifting or lowering the
load, and always consider the angle of lift when using a
sling chain bridle.
Store chains in a clean, dry place where they will
not be exposed to the weather. Before storage, it is a
good idea to apply a light coat of lubricant to prevent
rust.
Makeshift repairs, such as fastening links of a chain
together with bolts or wire, should never be permitted.
When links become worn or damaged cut them out of
the chain; then fasten the two adjacent links together
with a connecting link. After the connecting link is
closed and welded, it will be as strong as the other links.
For cutting small-size chain links, use bolt cutters. For
cutting large-size links, use a hacksaw or oxyacetylene
torch.
Inspection of Slings
Slings must be inspected frequently and removed
from service whenever defects are detected. Bear in
mind that a defective sling may cause serious injury to
personnel or extensive damage to equipment in case of
failure under load.
You should check FIBER-LINE slings carefully for
signs of deterioration caused by exposure to the
weather. You should also check closely to determine
whether any of the fibers have been broken or cut by
sharp-edged objects.
Broken wires are a major defect to look for when
inspecting WIRE-ROPE SLINGS. When four percent
of the total number of wires in the rope are found to have
nicks, or cuts, they should be replaced. However, if a
chain shows evidence of stretching or distortion of more
than five percent in any five-link section, make sure the
entire chain is discarded.
Figure 1-13.—Chain sling.
1-12
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