11-13
5540F/YB5515 SERVICE MANUAL STRUCTURALS
Wire Rope Safety
The following information is not a complete discussion of
wire rope. What follows is a brief outline of the basic
information required to safely use wire rope.
1. Wire rope WILL FAIL IF WORN-OUT, OVERLOADED,
MISUSED, DAMAGED or IMPROPERLY MAINTAINED.
2. In service, wire rope looses strength and work capability.
Abuse and misuse increases the rate of loss.
3. The NOMINAL STRENGTH, sometimes called
CATALOG strength, of a wire rope applies ONLY to a
NEW, UNUSED rope.
4. The Nominal Strength of a wire rope SHOULD BE
CONSIDERED the straight line pull which will
ACTUALLY BREAK a NEW UNUSED rope. The
Nominal Strength of a wire rope SHOULD NEVER BE
USED AS ITS WORKING LOAD.
5. WIRE ROPES WEAR OUT. The strength of a wire rope
begins to decrease when the rope is put to use and
continues to decrease with each use.
6. NEVER OVERLOAD A WIRE ROPE. This means
NEVER use the wire rope where the load applied to it is
greater than the working load determined by the rope
manufacturer.
7. NEVER “SHOCK LOAD” a wire rope. A sudden
application of force or load can cause both visible
external and internal damage. There is no practical way
to estimate the force applied by shock loading a rope.
The sudden release of a load can also damage a wire
rope.
8. Lubricant is applied to the wires and strands of a wire
rope when it is manufactured. The lubricant is depleted
when the rope is in service and should be replaced
periodically. See Preventative Maintenance, for
lubrication intervals and procedures.
9. In the U.S.A., regular INSPECTIONS of the wire rope
and keeping of PERMANENT RECORDS SIGNED BY
A QUALIFIED PERSON ARE REQUIRED BY OSHA
FOR ALMOST EVERY WIRE ROPE APPLICATION.
The purpose of the inspection is to determine whether or
not a wire rope may continue to be safely used on the
application. Inspection criteria, including number and
location of broken wires, wear and elongation, have
been established by OSHA, ANSI, ASME and similar
organizations.
IF IN DOUBT, REPLACE THE ROPE. An inspection
should include verification that none of the specified
removal criteria for this usage are met by checking for
such things as:
• Surface wear; nominal and unusual.
• Broken wires; number and location.
• Reduction in diameter.
• Rope stretch (elongation).
• Integrity of end attachments.
• Evidence of abuse or contact with another object.
• Heat damage.
• Corrosion.
In addition, an inspection should include condition of
sheaves, drums and other apparatus with which the wire
rope makes contact.
10. When a wire rope has been removed from service
because it is no longer suitable for use, it must not be
reused on another application.
11. Every wire rope user should be aware of the fact that
each type of fitting attached to a wire rope has a specific
efficiency rating which can reduce the working load of
the wire rope assembly or rope system, and this must be
given due consideration.
12. Some conditions that lead to problems in wire rope
systems include:
• Sheaves that are too small, worn or corrugated can
cause damage to a wire rope.
• Broken wires mean a loss in strength.
• Kinks permanently damage a wire rope and must be
avoided.
• Wire ropes are damaged by knots. Wire rope with
knots must never be used.
• Environmental factors such as corrosive conditions
and heat can damage a wire rope.
• Lack of lubrication can significantly shorten the
useful life of a wire rope.°
• Contact with electrical wires and resulting arcing will
damage a wire rope.
Inspecting Wire Rope
Inspect entire length of wire rope for any conditions listed in
Figure 11-13. If any of the conditions exist, replace the wire
rope.
If the wire rope shows severe wear, make a full inspection of
sheaves and drums for grooves, correct alignment, etc.
Inspection of Sheaves
Inspect all sheaves for wear and proper alignment.
For maximum life of the wire rope, the sheave grooves must
be smooth and must be a little larger than the diameter of the
wire rope.
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