Wednesday, 11 December 2019
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Easier mounting of lift ropes

End-customers continue to expect more and more from the lift industry. It is not just a question of standards and guidelines, such as the Operational Safety Ordinance, having to be observed.

Deflection pulley in indirect hydraulic lift. (Photo: © Licharz)

Design, durability and superior efficiency are also expected. Open design, in which the drive areas are visible through glass cladding, as well as weight reductions, have become increasingly common. This influences the configuration and construction space for lifts. Many assemblies have had to be reconstructed or reduced in size.

The result is increasingly smaller drives, which need less space. This has the advantage that when lighter materials are used, such as aluminium profiles, there is also a positive effect on energy consumption.

Greater assembly effort

The manufacturers of ropes and deflection pulleys face these challenges too. However, smaller diameters of deflection pulleys and the associated increase in flexural fatigue effects on the steel rope mean that the replacement state of wear for steel ropes is reached far earlier than in previous designs. Shorter rope life cycles in turn mean shorter running times, more overhauls and as a result higher costs. The market will not bear this.

HandwerkThis problem has been counteracted by the development of plastic-sheathed ropes and use of deflection pulleys made of plastic. But the small radii of the rope deflection in these combinations produce new unwanted effects.

At the first assembly of the lifts, the increased coefficient of friction between pulley sheave groove and plastic-sheathed ropes causes uneven rope tension in the system. This not only leads to greater assembly effort, in part it even produces uneven running or unwanted noise from the lift system in normal operation.

Reduce negative effects

Manufacturers of plastic-sheathed ropes have already succeeded in making progress to reduce these negative effects. Licharz GmbH, as a manufacturer of pulley sheaves, has developed the material version Linnotam Hiperformance E+ for use with rope deflection pulleys. Licharz has been known as a problem-solver in the lift industry for decades.

For example, together with lift construction designers, Linnotam Hiperformance E+ was developed in the course of countless test rig experiments with all kinds of formulations, especially for deployment in lift construction with deflection pulleys + plastic-sheathed ropes. The improved static friction coefficients ensure that when using deflection pulleys made of Linnotam Hiperformance E+, no problems arise during spooling which increase the effort involved in assembly.

The noise that can occur during everyday operation from friction between the rope and previously used deflection pulleys likewise no longer occurs when using Linnotam Hiperformance E+.

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