Liebherr Biberach has added a fourth model to its range of cantilever jib – or flat top – tower cranes. The 280 EC-B 12 is also the first flat top in which Litronic hoisting technology, used in its saddle jib tower cranes, comes installed as standard. Liebherr claims that the system, which slows down the hoist and trolley movement, increases capacity by 20%.

The crane has a load moment of 343tm. It can lift 12t out to a radius of 29m, and 2.5t at the end of its 70m jib.

Flat top towers are popular in sites where space is tight because they can more easily oversail each other. In some cases, local law might specify a maximum crane height. In complex but small construction sites, several flat top cranes can operate with less risk of hitting one another.

Compared to conventional A frame saddle jib cranes, flat tops can be easier to set up. Because jib sections on flat tops have no external support, the entire jib can be constructed by pinning a new section on the end of the other. By the same token, should riggers need to lift a load over a longer range, or lift a heavier load, they can add or remove jib sections without dissasembling the entire jib. (For more information, see CT April 2001, pp 19-25).

On the down side, flat top jibs tend to be heavier in order to bear the stresses along their length. Because of its greater strength, the 280 EC-B 12’s jib weighs 15% more than the jib of the slightly heavier duty 280 EC-H Litronic saddle jib crane. Given its scale, the 280 EC-B 12 might be thought to be especially unwieldy. But it breaks down into 7.5t sections for transportation. In particular, the crane’s combined cab and central section separate from the slew ring beneath it.

The 280 EC-B 12 slewing ring mounts atop the same tower sections that the saddle jib EC-H range does – the 256, 355 and 500HC tower models. For that reason, the length of tower sections and the height under hook are the same as the 280 EC-H 12. The 256HC tower, with 6m undercarriage, has 4.1m sections and a total height under hook of 56.7m. The 355HC, with 8m base, has 5.8m sections and a total height under hook of 75.2m. The 500HC with 10m base has 5.8m sections and a total height under hook of 86.8m. The 280 EC-B also shares some jib sections with the EC-H range of saddle jib tower cranes.

Liebherr reports that it has delivered ‘several’ units to customers in Europe already.