Wire rope is integral to lifting, shifting and power transmission across a host of industries, starting with mining in the 1830s and since then extending across wide swathes of industry.
Uses today include cranes and lifting, cargo handling, elevators, construction, primary and food product harvesting, power generation technology (such as tendons in windmills), winching and conveying in manufacturing, minerals processing and materials handling and fixed and mobile plant used in paper and timber processing.
The major initial advantage of wire rope over the chains it replaced was that it would not snap catastrophically where there were flaws in chain links or solid bars, but rather individual strands could fail while others around them would take up the load safely and flexibly without shock.
However, even the best quality wire rope will ultimately wear and potentially fail if it is subjected to constant abrasion, such as that induced by uneven metal-to-metal contact across sheaves and where lubricants attract grime to gradually compromise strength while attracting impurities into industrial processes.
To help protect against such issues, Cut To Size Plastics custom-engineers sheaves and rollers for wire ropes using some of the world’s hardest-wearing engineering plastics, formulated to reduce wear and maintenance and enhance safety in a wide range of machinery and materials handling equipment.
Examples of such sheaves are fabricated from Cut To Size’s internationally proven Wearlon range of hard-wearing cast polyamide engineering plastics, such as the Linnotam products of the globally respected Licharz organisation. These products are formulated both for OEM use and metal replacement in applications involving transmission of mechanical force and minimising friction.
According to Cut To Size Managing Director Laurie Green, “Steel wire ropes are important and highly stressed machine elements in force transmission and conveying technology. In many cases, large plant depends on their functioning not only for efficiency but also safety. Wearlon can extend lifespan and enhance safety by reducing maintenance and preserving structural integrity for longer.”
“Wire ropes are stressed by fluctuating forces, by wear, by corrosion and by extreme forces. Ropes that run over sheaves made from metallic materials are subject to high stress due to the surface pressure that occurs between the rope and the groove. When the rope rolls over the sheave, only the outer strands lie on the groove. The result of this is wear in the form of individual strands breaking or, more serious, rope breakage,” says Green.
“Sheaves made from Wearlon prevent this due to their elastic behaviour. The pressure between the rope and the roller in the combination steel rope/polyamide roller is around 1:10 compared to steel rope/steel roller. This can be attributed to the viscoelastic behaviour of polyamide. It is not just the outer strands that lie in the groove, but almost the whole projected strand width. This reduces surface pressure between the rope and the roller and considerably extends the life of the rope.”
Cut To Size Plastics
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