Tower crane specialist Wolffkran has introduced a new luffing jib model, the WOLFF 235 B, which aims to save time for contractors with a design that speeds up assembly and maintenance.
A statement from the manufacturer said the new model was developed to replace the popular WOLFF 224 B in its stable and ranks between the hydraulic WOLFF 166 B and the next larger WOLFF 275 B in the lower load moment range, fulfilling the demands of construction sites with a high volume of concreting work on high-rise buildings.
Wolffkran added that the premise behind developing the new WOLFF 235 B was that the faster a crane is ready for operation, the more cost effective it is.
Wouter van Loon, product manager at Wolffkran, said: “The WOLFF 235 B was developed in close collaboration with Wolffkran customers from the UK, who have decades of experience in handling luffing cranes on inner-city construction sites. The result is a (crane) with a proven duty chart that is unrivalled when it comes to assembly and versatility.”
The manufacturer added that although Wolff cranes are generally easy to assemble, it has raised the bar to yet another level with this latest model. The hoisting gear of the new WOLFF 235 B is positioned on the jib rather than the counter jib as is typical, and Van Loon added: “This makes it possible to reeve the hoisting rope on the ground and thus completely pre-assemble the entire jib. As well as being very convenient and safe, it is also a novelty for luffing jib cranes of this size.”
The luffing gear can be mounted either on the counter jib or on the tower top during the assembly process, which offers more flexibility with regards to the size of the mobile crane. The second option has the advantage that the entire tower top including the hoisting gear with pre-reeved pulley block can be transported and lifted onto the crane as a single unit, which is an enormous time saver, said Wolffkran.
“In addition, the cabin platform with the WOLFF Cab and switch cabinet can be placed on the empty counter jib during transportation,” added Van Loon.
Overall low component weights ensure that a WOLFF 235 B can assemble another of its kind at a jib radius of 40m, said thew statement, pointing out that this is a preferred process on multi-crane city sites where space is often an issue and also saving on time and money for a mobile crane.
The WOLFF 235 B is also developed for economical maintenance, with features such the use of an identical winch for both the hoisting and the luffing gear. Wolffkran said it opted for the tried and tested 60kW winch Hw 1160 FU that it uses in many other models. This is also the case with the slewing gear and the frequency converters that are used in the 235 B. The benefit of this is economical warehousing as fewer different spare parts have to be stocked, while training of service technicians is also simplified.
The same principle applies to the 8t counterweight blocks that are used in all next larger Wolff luffing jibs cranes. “Also, the new model manages with only four counterweight blocks, which means that only four lifts are required for the complete ballasting of the crane,” said Van Loon.
The WOLFF 235 B offers a maximum load capacity of 8t in single-fall and 16t in two-fall operation and jib lengths from 30-60m. Designed to deliver its best performance with a 50m jib, it offers a tip load capacity of 4.1t. Its 60kW hoisting winch allows for working speeds of up to 130m/min and a rope storage capacity of 620m. It can reach a maximum freestanding height of 82m using standard components from the modular WOLFF tower system. These features make it well suited for high-rise construction with reinforced concrete, said Wolffkran.