"Power boom" for Liebherr lattice

Since the middle of September, a lattice boom crane has been towering 150 m above the ground at the Liebherr factory site in Ehingen, Germany —­ in a form that has never been seen before. At the lower part of the crane the lattice sections are assembled parallel to each other; at the top, the double boom has been joined together to form a single boom. This "parallel boom" is the newly developed P-boom - "power boom". This innovation from Liebherr can certainly be described as trailblazing, since lifting capacity increases of more than 50% can be achieved with relatively little effort.

The parallel lattice sections are joined near the slewing platform with the "lower P-adapter" and are bolted to the crane. At the top of the crane, the double boom is joined with the "upper P-adapter" and is extended with a simple lattice system. The power boom not only improves stability in the direction of the load, but also to the side, which results in enormous increases in lifting capacity with long boom systems. The serial luffing fly jib can be attached, with its lifting capacity also being increased considerably by the increase in the torsional moment of the power boom.

In general, only standard intermediate sections are used with the power boom. The advantages are that only the lower and upper P-adapters are needed additionally and that the crane operator has a crane with lifting capacities in the next higher crane category. This produces an optimum price-performance ratio.

The power boom is designed so that it can be offered as an option and can also be retrofitted to cranes that have already been delivered. Customers only have to invest in a power boom when they have a job that requires the corresponding lifting capacity. Cost effectiveness is also ensured by the fact that the P-adapters can be used for several cranes of the same type. The slewing platform, derrick boom and luffing fly jib remain the same. The base section is designed so that a single or parallel boom can be attached to the crane's slewing platform.

The power boom was first designed for the 3,000-tonne LR 13000 crawler crane. But then, because of the high increases in lifting capacity, Liebherr also developed it for the LR 11350 on which it is currently assembled and being tested. Because standard lattice sections are used, the boom can also be retrofitted to LR 11350 cranes that have already been delivered. Customers only have to buy the P-adapters.

Liebherr's innovative new development of the power boom system sets new benchmarks in the large lattice boom crane segment and will therefore also play a major role in future developments of new crane types. It is also part of a whole range of measures being implemented by Liebherr to optimise lifting capacities and to extend the application spectrum of various models, such as in the area of wind turbine assembly with cranes in the 600-tonne to 750-tonne range.