TM5-3810-305-10
4.
5.
6.
7.
Because criteria for removal are varied, and
because diameter, in itself, is a vague crite-
rion, the table of minimum diameters has
been deliberately omitted from this manual.
Corrosion: Corrosion, while difficult to
evaluate, is a more serious cause of degrada-
tion than abrasion. Usually, it signifies a lack
of lubrication. Corrosion will often occur
internally before there is any visible external
evidence on the rope surface. Pitting of wires
is a cause for immediate rope removal. Not
only does it attack the metal wires, but it also
prevents the rope’s component parts from
moving smoothly as it is flexed. Usually, a
slight discoloration because of rusting merely
indicates a need for lubrication.
Severe rusting, on the other hand, leads to
premature fatigue failures in the wires, neces-
sitating the rope’s immediate removal from
service. When a rope shows more than one
wire failure adjacent to a terminal fitting, it
should be removed immediately. To retard
corrosive deterioration, the rope should be
kept well lubricated. In situations where
extreme corrosive action can occur, it may be
necessary to use galvanized wire rope.
Kinks: Kinks are permanent distortions
caused by loops drawn too tightly. Ropes
with kinks must be removed from service.
“Bird caging”: Bird caging results from tor-
sional imbalance that comes about because of
mistreatments such as sudden stops, the rope
being pulled through tight sheaves, or wound
on too small a drum. This is cause for rope
replacement unless the affected portion can be
removed.
Localized conditions: Particular attention
must be paid to wear to the equalizing
sheaves. During normal operations this wear
8.
9.
is not visible. Excessive vibration or whip
can cause abrasion and/or fatigue. Drum
crossover and flange point areas must be care-
fully evaluated. All end fittings, including
splices, should be examined for worn or
broken wires, loose or damaged strands,
cracked fittings, worn or distorted thimbles
and tucks of strands.
Heat Damage: After a fire or the presence of
elevated temperatures, there may be metal
discoloration or an apparent loss of internal
lubrication; fiber core ropes are particularly
vulnerable. Under these circumstances, the
rope should be replaced.
Protruding Core: If, for any cause, the rope
core protrudes from an opening between the
strands, the rope is unfit for service.
10. Damaged End Attachments: Cracked, bent,
or broken end fittings must be eliminated.
The cause should be sought out and cor-
rected. In the case of bent hooks, the throat
openings - measured at the narrowest point -
should not exceed 15% over normal nor
should twisting be greater than 10%.
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