Feldmann’s Leibherr Rooster Sheave Adds Extra Centimetres

A mighty Liebherr tower crane was erected to carry out conversion work on a castle in the Swiss municipality of Rapperswil-Jona. A mobile crane of the type LTM 1450-8.1 provided the necessary power in this medieval town on Lake Zurich. Due to the limited space in the castle’s elevated surroundings, the crane assembly had to be carried out at a considerable distance. Radii of up to 48m were required for this purpose. Due to the use of a whip line on the pulley head, it was not necessary to attach a lattice jib.

Steady: From the sloping street of the old town, the modern Liebherr crane completed all the lifting work swiftly and without any problems.

For extensive conversion work on Rapperswil Castle, a large type 172 EC-B construction crane had to be erected for Bernet Bau AG. For this to be possible, a large gantry first had to be assembled to create a set-up area for the tower crane.

172 EC-B 8 Litronic Flat-Top Tower Crane

The topography around the 800-year-old complex, which towers over the old town of Rapperswil-Jona, did not allow access by lorry or with heavy machinery, which meant the assembly work could only be carried out at an extended distance. The Liebherr LTM 1450-8.1 mobile crane from Feldman Pneukran + Transport AG, based in Bilten east of Lake Zurich, was used for this task. Over a distance of almost 50m, the modern mobile crane had to lift the parts of the steel substructure and the individual components of the top-slewing crane to the construction site.

Clever solution: When attaching the construction crane’s slewing ring, the 85m telescopic boom on the LTM 1450-8.1 reached its limits in terms of hook height and radius. The use of a rooster sheave spared the Feldmann team the more complex installation of a lattice jib.

Thanks to the hydraulically adjustable VarioBallast® system, only 104t of counterweight at maximum radius were sufficient for the LTM 1450-8.1 to handle even the heaviest loads during this job. The construction crane’s 60m long main boom represented the heaviest of the components with a gross load of 10t. The only shortage of telescopic length occurred when the slewing ring was installed at a hook height of almost 70m. To compensate for this, the Feldmann team had fitted a rooster sheave to the pulley head on the telescopic tip of the mobile crane. “The rooster sheave effectively gives us about 80cm to 90cm more radius and saves us having to add a lattice jib,” explained Manfred Moosmann, Feldmann’s crane driver on the LTM 1450-8.1.

Manfred Moosmann sat at the controls of the 8-axle Liebherr mobile crane during the crane operation in Rapperswil-Jona. The experienced crane driver has been working for Feldmann Pneukran + Transport AG for 19 years

Not only did Moosmann and his powerful mobile crane assemble the construction crane and portal, which will allow public access to the castle grounds during the renovation work, but they also equipped the construction site with containers and other materials in two days, which were hoisted into position from the lower-lying old town. The plan is to erect the LTM 1450-8.1 once again between the picturesque houses of the old town in summer 2024, in order to dismantle the tower crane once the work on the medieval fortress building has been completed.

Feldmann Pneukran + Transport AG has three locations in the region around Lake Zurich, which it uses for activities focusing on crane work, heavy transport and assembly technology. The company has two dozen mobile cranes and mobile construction cranes in operation. Among them is the first Liebherr mobile crane of the type LTM 1300-6.3 to be delivered.

Featured Title photograph

800-year-old backdrop: The LTM 1450-8.1 was not only needed to assemble the Liebherr 172 EC-B 8 Litronic Flat-Top construction tower crane with the 60m long main boom at a distance of around 50m – containers and other construction site equipment also had to be transported to the castle on crane hooks from the lower-lying old town.

Source Liebherr