'The rooster sheave adds the last few centimetres'

For extensive conversion work on Rapperswil Castle, a large type 172 EC-B construction crane had to be erected. For this to be possible, a large gantry first had to be assembled to create a set-up area for the 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 50 metres, 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.

Thanks to the hydraulically adjustable VarioBallast® system, only 104 tonnes 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 60-metre-long main boom represented the heaviest of the components with a gross load of ten tonnes. The only shortage of telescopic length occurred when the slewing ring was installed at a hook height of almost 70 metres. 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 80 to 90 centimetres more radius and saves us having to add a lattice jib," explained Manfred Moosmann, Feldmann's crane driver on the LTM 1450-8.1.

Disassembly of the construction crane planned for the coming year

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 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.