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10.2 IRREGULAR MAINTENANCE
[1] REPLACEMENT WINCH WIRE ROPE
Always wear work leather gloves when replacing the wire rope.
• A diameter of the wire rope is to be measured at points where the wire repeatedly runs through
the sheave. A mean value needs to be determined through three-way measurement. (A
measurement should be performed at several points, spacing between the points.)
• Do not use the old wire rope regardless of the frequency of use.
• Always use Maeda genuine wire rope.
[CRITERIA FOR WINCH WIRE ROPE REPLACEMENT]
A wire rope undergoes wear and tear over time.
Prompt replacement is required if any of the following
events appears in the wire rope.
1. Percentage of the snipped wires in total wires (except
filler wires) in outer strands exceeds the ratio below:
(1) 10% or more of the wires in one twist of the wire rope,
or 5% or more when such nipped wires are in one
single strand..
(2) 20% or more of the wires in five twists of the wire rope.
2. The diameter of the wire rope is worn for 7 % or more of the
nominal diameter
• Replace a 10 mm diameter wire rope if it is 9.4 mm in diameter.
• Replace a 8 mm diameter wire rope if it is 7.5 mm in diameter.
3. The wire rope, corroded as below:
(1) Wire surface has pitching and pitting.
(2) Wires become slack due to internal corrosion.
4. Excessively deformed as below:
(1) The rope is twisted and has some kinks.
(2) Waviness width is 4/3d or more in a distance within 25 times
of nominal diameter d.
(3) The minimum diameter is 2/3 or less of the maximum
diameter due to local pressure and being flattened.
(4) Core wire or wire core projects.
(5) Excessively curved.
(6) Basket-like deformation.
(7) A strand sinks inside.
(8) One strand or more is slack.
(9) Wires project excessively.
5. The rope shows some abnormality at the terminals.
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