Wire ropes are critical to the safe and reliable performance of your lift.
Cables are expendable items and should be replaced as a set.
A wire rope may be looked upon as a machine composed of a large number of moving parts. As such it should be broken in as soon as it is installed, by loading it very lightly for a few cycles and then gradually stepping up the load, to enable both wires and strands to ‘bed down’ into the working positions, with the load distributed as uniformly as possible.
Wire rope is tough and durable, but nonetheless expendable and eventually reaches the end of its safe service life. Rope deterioration becomes noticeable through the presence of broken wires, surface wear, corrosion, wire or strand distortion due to mechanical abuse, or drastic reduction in diameter and lengthening of the lay. Also deterioration can be detected by the use of non-destructive testing techniques. Wire ropes should periodically be inspected for signs of deterioration.
When to replace
The Wire Rope MUST be Replaced if One or More of the Following Criteria Are Met:
• More than six (6) randomly distributed broken wires in one rope lay or 6xd length.
• More than three (3) broken wires in one strand in one rope lay or 6xd length.
• Three (3) or more broken wires at rope terminations.
• One outer wire broken at the point or contact with the core of the rope whish has worked its way out of the rope structure and protrudes or loops out from the rope structure.
• Heavy rusting, corrosion, or pitting. A light surface corrosion on outer wires is normal.
• Wear or scraping of one-third (1/3) of the original diameter of outside individual wires.
• Excessive stretch. It is normal for new cable to require adjustment during “break-in,” after which small periodic adjustments may be required. However, if a cable that has been in service for 6 months should suddenly require frequent adjustments or has used all the cable adjustments available, all cables must be replaced immediately.
• Deformed strands, kinking, crushing, bird-caging, or any other damage or distortion of wire rope structure.
• Variations in diameter (necking) or any change from normal appearance.
• End attachments cracked, deformed or worn.
* Lay is the distance measured, parallel to the rope axis, in which a single strand makes one complete turn around the rope axis, or the wires make a complete turn around the axis of the strand.
Please refer Australian Standard for Steel Wire Ropes AS 3569 for more information on wire rope cable inspection.