T M 5 - 3 8 1 - 3 0 5 - 1
c.
d.
e.
f.
Crane hooks for excess throat opening or
twisting along with a visual for cracks.
Wire rope and reeving for conditions
causing possible removal.
Wire rope slings for excessive wear,
broken wires, kinking, twisting and me-
chanical abuse.
All end connections such as hooks, shack-
les, turnbuckles, plate clamps, sockets, etc.
for excessive wear and distortion.
4. An Annual Inspection with a signed report
must be made for the following:
a.
b.
c.
d.
Crane hook for cracks.
Hoist drum for wear or cracks.
Structural members for cracks, corrosion
and distortion.
For loose structural connections such as
bolts, rivets and weldments.
Wire Rope Inspection
The following is a fairly comprehensive listing of
critical inspection factors. It is not, however,
presented as a substitute for an experienced
inspector. It is rather a user’s guide to the ac-
cepted standards by which ropes must be judged.
1. Abrasion: Rope abrades when it moves
through an abrading medium or over drums
and sheaves. Most standards require that rope
is to be removed if the outer wire wear ex-
ceeds 1/3 of the original outer wire diameter.
This is not easy to determine and discovery
relies upon the experience gained by the
inspector in measuring wire diameters of
discarded ropes.
2. Rope stretch: All ropes will stretch when
loads are initially applied. As rope deterio-
rates from wear, fatigue, etc. (excluding
accidental damage), continued application of
a load of constant magnitude will produce
varying amounts of rope stretch. A “stretch”
curve plotted for stretch vs. time (Figure 4-
41) displays three discrete phases:
a.
b.
c.
Initial stretch, during the early (beginning)
period of rope service, caused by the rope
adjustments to operating conditions (con-
structional stretch).
Following break-in, there is a long period -
the greatest part of the rope’s service life -
during which a slight increase in stretch
takes place over an extended time. This
results from normal wear, fatigue, etc. On
the plotted curve - stretch vs. time - this
portion would almost be a horizontal
straight line, inclined slightly upward from
its initial level.
Thereafter, the stretch begins to increase at
a quicker rate. This means that the rope is
reaching the point of rapid deterioration; a
result of prolonged subjection to abrasive
wear, fatigue, etc. This second upturn of
the curve is a warning indicating that the
rope should soon be removed.
Figure 4-41. S tretch vs. Time
4-45
