When a wire rope is used in the lifting of a heavy load, it is normal for the rope to encounter some degree of twisting. If the twisting becomes too severe, however, you may encounter wire rope twisting problems that can be detrimental to your project and even hazardous to you and your team’s safety. In rigging and hoisting applications, wire rope twisting (or cabling) is one of the more common problems you’re bound to encounter, especially in older wire ropes.
How to Avoid Wire Rope Twisting
Every rigging application is different and you’ll always want to have a proper handle on every aspect of your rigging application before beginning. Fortunately, with a few simple steps, you can help avoid wire rope twisting problems before they cause potentially catastrophic and irreversible damage.
Reduce Weight of Load Being Lifted
Though not always feasible, reducing the weight of the load itself can lower the tension of the wire rope and, as a result, the risk of excessive twisting.
Use a Tagline
A tagline is a rope attached to a load during hoisting in order to provide more control and prevent swinging or rotation of the load. By offering an added level of control over your suspended load, you can help reduce the amount of stress placed on the wire ropes and minimize the risk of twisting problems.
Reduce Wire Rope Length
If possible, consider reducing the length of your wire rope apparatus. Doing so can help minimize the amount of twisting subjected to the rope itself, thus preventing kinking and blocking.
Avoid odd-part reeving
Operating with an odd number of parts can cause a load to be unstable. If possible, consider adding a part and operating with an even number. It may add time to the operation, but it will help ensure safety and protection of your equipment and your load.
Use Rotation Resistant or Low Rotation Rope
Rotation resistant rope is comprised of at least fifteen outer strands in at least three layers laid over a center in two operations. This rope is significantly less likely to twist and will generate little to no torque when loaded.
Disconnect Rope and Start Over
In applications with short ropes, you may be able to avoid cabling by simply disconnecting the rope and laying it along the ground. This will allow any twists or tension to be released, thus minimizing the potential for twisting problem.
Examples of Wire Rope Twisting Problems
When wire ropes are subjected to severe twisting and abuse, it is not uncommon to notice types of wire rope deterioration. Common signs of hyper-twisted wire rope or torsional imbalance include looped wore, “bird caged” rope in which inner strands become protruded from the main line, bending fatigue, or broken wire on lower layers. If your rope sustains any of these twisting problems, you’ll want to retire it from future rigging applications. By using wire ropes properly and minimizing twisting potential, you can extend the life of your wire ropes.
Conclusion
Before embarking on a complicated rigging or hoisting project, you’ll want to familiarize yourself and your team with every aspect of what’s involved. Surprises in the middle of your operation are typically not pleasant ones, so you’ll want to go over every point in detail (and that includes addressing any wire rope twisting problems you’re likely to encounter). And if you have questions about wire rope rigging or slings, contact the wire ropes experts at John Sakach to help you get the rigging job done safely and efficiently.
Login