Synthetic fibre rope for Wolff tower cranes

The new chaRope developed by Wolff and Trowis is a multi-layered twisted synthetic fibre rope core with a monolithic polymer cover. Photo: Wolffkran

Tower crane manufacturer Wolffkran is launching a synthetic fibre hoist rope to replace conventional steel wire hoist rope.

It said its new chaRope, developed with rope specialist Trowis, is “the only fibre rope that can replace a steel rope 1:1.” Visitors to the Bauma exhibition in Munich, Germany, from 24 to 30 October 2022, can see the new red rope on a Wolff 6021 FX flat top tower crane.

In addition to the usual advantages of fibre rope over steel, Wolff said, substitution of steel with the new rope can be done without any modification of the crane.

The new Trowis rope has a distinctive full cover and is the same diameter overall as the steel rope it replaces. “Thanks to the unique design, the chaRope fibre rope has the same diameter as a steel rope and is thus significantly thinner than comparable products from competitors,” said Thomas Heidrich, Wolffkran CTO and board member.

“The design consists of a multi-layered, twisted core made of high-tensile high-tech fibres and an abrasion-resistant, thin-walled fibre composite cover,” said Thorsten Heinze, Trowis managing di-rector. “Thanks to this structure, we can offer 12- and 16-mm diameter crane ropes at market entry.”

All Wolff cranes with 12 or 16 mm steel rope can have the new fibre rope instead. No adjustments to sheaves, hoisting gear, or load capacity are needed, Heidrich said. “In our current portfolio, this applies to all models in the Wolff Clear series, the new Wolff 21 FX cranes and the Wolff 8033.16 Cross.”

the fully sealed sheath type cover on the Trowis hoist rope keeps moisture away from the core fibres, reduces damage from abrasion and increases the life of the rope, Wolff said. Photo: Wolffkran

Fully sheathed cover

A distinctive feature of the new fibre rope is that its cover is an impermeable full sheath, unlike the braided cover of competing products. Moisture can’t penetrate to the inside of the rope and at the same time lubricants can’t leak out. “The rope does not run dry, even after many years, and the environment is not polluted with microscopic plastic,” said Peter Streubel, Trowis managing director. In addition, this cover gives the core of the rope complete protection against the damaging effect of ultraviolet rays in sunlight. Any damage to the cover acts as a wear indicator, showing when the rope needs to be discarded.

Testing of the new rope is ongoing. “The test phase will be completed in June 2023 and the rope will be available on the market in August 2023,” Heidrich said. Field testing will be carried out on Wolffkran’s UK rental fleet.

“In the medium term, we plan to develop further fibre ropes with other typical diameters, together with Trowis, to offer the entire Wolff crane range with the innovative fibre rope,” Heidrich concluded.