Manitowoc MLC650, Service Maintenance Manual

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Reference
Only
HOISTS MLC650 SERVICE/MAINTENANCE MANUAL
5-78
Published 09-09-16, Control # 229-09
diameter can be caused by loss of core support, internal or
external corrosion, or wear of the outside wires.
After initial loading, measure and record the diameter of any
new wire rope for comparison to future inspections (see
Maintain a Wire Rope Condition Report on page 5-75 ).
The wire rope must be taken out of service when the
reduction from its nominal diameter is more than 5
percent.
Broken Rope Wires
When conducting the periodic comprehensive inspection,
thoroughly clean the wire rope so breaks can be seen. Relax
the rope, move it off “pick-up points,” and flex it as much as
possible. Use a sharp awl to pick and probe between the
wires and strands, lifting any wire which appears loose or
moves excessively.
Do not open strands of rotation-
resistant rope.
Wire breaks are typically at the crown of the strands—the
area that contacts the sheave or drum when a load is picked
up. Breaks at the crown will appear as small gaps in a wire.
In comparison, when wires in the valley of a strand break, the
broken ends will rise up and are easier to notice.
NOTE: The daily inspection does not require that the rope
be cleaned or probed.
The wire rope must be taken out of service when it has the
following number of broken wires:
See Figure 5-45 for an explanation of lay length.
• Running ropes—six randomly broken wires in one lay
length or three broken wires in one strand in one lay
length
• Standing ropes (pendants)—more than two broken
wires in one lay length in sections beyond the end
attachment, or more than one broken wire at the end
attachment (
Figure 5-44 )
• Rotation-resistant rope—two randomly distributed
broken wires in six-rope diameters or four randomly
distributed broken wires in 30-rope diameters
• All ropes—one outer wire broken at the point of contact
with the core and protrudes or loops out of the rope
structure—additional inspection is required
• End attachments ( Figure 5-44 )—when more than one
broken wire appears at the attachment, replace the rope
or cut off the affected area and reattach the fitting
NOTE: For galvanized bridle strand wire rope pendants—
United States Steel states, “Replacement criteria
for galvanized strand boom suspension pendants
are 25 percent of the outer wires fractured, or 10
percent of the total numbers, whichever comes
first.”
WARNING
Falling Load Hazard!
A broken wire indicates a weakened wire rope. Replace
wire rope when more than one broken wire appears.
Measuring Technique
Incorrect
Correct
FIGURE 5-43
Item Description
1 Swagged Socket
2 Wedge Socket
3 Poured Zinc Socket
4 Hand-Spliced Socket
5 Button Socket
FIGURE 5-44