Lerchenberg 10 | 86923 Finning

Rope winding technology from LEBUS®Still have questions? We know the answers!

Beratung LEBUS® Technik

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Advice on all aspects of the LEBUS® system

We value personal consultation. Through direct discussions, we find solutions and develop new ideas tailored to your specific application. However, some questions come up frequently. That’s why we have compiled a selection of common inquiries—our FAQs. Is your specific question not covered? Feel free to contact our experts in Finning am Ammersee.

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What factors influence the lifespan of the rope in multi-layer spooling?

With multi-layer rope spooling, there are several factors that influence the service life of the wire rope:

  • the ratio of the drum diameter to the nominal diameter of the rope: D:d ratio
  • Rope tension: slack, loose, too tight, maximum and minimum rope tension
  • Safety coefficient of the rope: Breaking load divided by the maximum working load
  • Rope diameter tolerances
  • Rope structure or rope type
  • Correct installation of a wire rope
  • Training of winch operators

What is the D:d ratio?

The ratio D:d describes the relationship between the drum diameter center to the first rope layer (PCD) = D and the rope diameter = d.

How does the D:d ratio affect the lifespan of the rope?

Our experience has shown us that rope damage increases significantly with a decreasing D:d ratio. Due to the bending stiffness of wire ropes, D:d ratios below 23 should be avoided.

What influence does rope tension have when spooling involves more than one layer?

If the dead windings are wound too loosely, gaps will occur between the windings when spooling from the second to the third layer. Under certain circumstances, these can lead to destruction of the outer wire strands.

What is the minimum preload required for the LEBUS® groove?

The preload is the line load on the rope drum. As a rule, this should be at least 1-2 % of the breaking load of the rope or 10 % of the working load. However, the safety factor and the rope construction must never be disregarded.

What happens when slack rope occurs?

As soon as the minimum preload is not reached, individual rope windings may become loose. This can cause the rope to cut or be damaged during spooling.

What is a LEBUS® half shell?

The LEBUS® half-shell is a balanced, machined, grooved half-shell that is normally split lengthwise. This means that the two half-shells of the LEBUS® system can be easily installed on a rope drum without having to dismantle it.

What materials are LEBUS® half shells made from?

Our half-shells are normally made of steel. The half-shells are mounted on a smooth rope drum without grooves by welding or bolting or a combination of both fastening options. S355J2G3 (St.52-3) is used as standard. However, special steels such as STE690, STE890 and STE960 are also increasingly being used. If required, we can also supply systems made of aluminum or plastic.

What is the lifespan of LEBUS® half shells?

In our 60-year history, we have never replaced a system due to wear and tear.

Why should I choose LEBUS® half shells?

The grooves for multilayer rope spooling can either be cut directly into the drum core or LEBUS® half shells can be used. The following points speak in favor of the half shells:

  • From an economic point of view, it can make sense to retrofit an existing cable drum. This usually saves money and time.
  • For new wire ropes with different specifications, it may be easier and cheaper to replace the half-shells than to replace the rope.
  • Split half shells offer more flexibility when making changes.
  • In general, we always recommend half shells for windings with more than 25 windings and more than four layers.

On what types of cable drums can I mount LEBUS® half shells?

Any type of cable winch can be retrofitted with a LEBUS® groove or half-shell if the technical regulations are observed.

What are wear plates?

What types of rope attachments or rope clamping systems are there?

The correct design of the LEBUS® groove depends on how the rope is attached and inserted into the first groove. There are seven general forms of rope entry: – Thread through flange (TTF)
– Pocket in flange (PIF)
– Vertical wedge (VW)
– Horizontal wedge (HW)
– Thread through core (TTC)
– Groove rope core socket (GRCS)
– Tail-line rope core (TLRC)

What is a kicker?

We use the term kicker in connection with our multi-layer spooling and refer to a pair of thin, rectangular steel plates that are attached to the flange surfaces of a drum by welding or bolting. The kicker plates can turn or deflect the wire rope into its correct path at the right time when spooling onto the drum. If the rope deflection angle is too small and the rope tends to build up a flange when changing layers, the kicker plates are used. In many cases, wire ropes build up at the flange as soon as the rope deflection angle is less than 45′. It also depends on the rope structure, the diameter and the speed at which the rope is spooled onto the drum. Kickers can be used successfully with the LEBUS® groove because the wire rope crosses at the same point in every single layer. We do not recommend kickers if the spooling involves more than three layers and 25 grooves.

At which point on the drum circumference are kickers installed?

Kickers are always placed near the center line of the crossing areas of the grooved rope drums or half shells. This is where the ropes make their first crossing movement away from the flange and towards one or both sides of the drum. This point is above the groove area, which transitions from zero to half a groove. Kickers can be welded to flanges or wear plates or bolted with flat Allen screws. Caution: Kickers must never be installed above the filler piece (rope entry) and the overflow (rise to the second layer).

What is the fleet angle?

The rope deflection angle is defined as the largest angle of the rope between the first rope sheath and the drum flange in relation to the center axis of the drum.

What is the recommended fleet angle when spooling multiple layers without using a spooling device?

Experience and tests show that the maximum rope deflection angle should not be greater than 1°30′ and not less than 45′. If it is too large, the rope tends to be pulled away from the flange too quickly. This creates gaps into which the rope can fall during subsequent layers, causing it to be cut, compressed and damaged.
If the rope deflection angle is too small, the rope cannot be pulled away from the flange quickly enough. In this case, the rope tends to wrap over each other on the flange and then fall down with considerable force. The resulting impact can damage not only the rope, but also the equipment on which it runs.

What fleet angle should be observed with a normal groove?

For single-layer wound rope drums, the lead angle should not exceed 3°

How many layers can I reliably spool with a LEBUS® groove?

There are no limits to the LEBUS® system if the given system parameters are adhered to (link Quality & products). As a rule, three to 16 layers are wound with the LEBUS® groove. However, 40 layers have also been successfully wound in oceanography, for example.

How many layers can I spool with a normal groove?

We generally recommend the normal groove for single-ply applications. It should not be used to wind more than two layers. When winding two layers, a LEBUS® end filling piece is advantageous when changing from the first to the second layer.

What is the “Cut and Slip Procedure” or CSP?

The “Cut and Slip Procedure” or CSP is a visual inspection for wear of the wire rope at the crossing areas. If the first signs are visible, the rope does not have to be discarded. Instead, a short length is cut off at the end of the drum (approx. 1.5 times the crossing length) so that other areas of the rope run over the crossing areas. This measure can be repeated two or three times so that the service life of the wire rope is doubled or tripled.

Enough reading.

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