Liebherr has developed a special erection frame for the LR 1750, its 750t capacity lattice boom crawler crane.
The attachment is designed specifically for wind turbine erectors, allowing them to install 120m high hubs without a crane derricking system. The specially designed frame is pinned to the back of the superstructure and then counterweight is suspended from it. This allows the main boom, up to 130m, to be assembled without any supports needed under the boom.
Counterweight that can be suspended could be the normal ballast sections used on the LR 1750, or even, as shown in a photo on the news pages of the December issue of Cranes Today, a mobile crane. Liebherr points out that a mobile crane will usually be available around a jobsite where a crawler crane is being rigged.
The advantage of this system, according to Liebherr, is that the crane can be aligned in any direction before boom assembly. Normally the boom would have to be attached in alignment with the the direction of the mechanical outriggers on the crawler tracks. This new system means that the outriggers are not needed. Therefore the crane be assembled in the direction of travel toward the turbine and so does not have to slew on the spot with rigged boom and tear up the ground beneath.
First customers for the new erection frame are the German companies Breuer & Wasel and Wiesbauer.