Liebherr has developed a novel type of telescopable derrick counterweight trailer for its 400t crawler crane the LR 1400/1.

The telescopable counterweight trailer has a variable turning radius and, claims Liebherr, “advantageous transport dimensions”. The two-axle trailer is attached to the crane superstructure by a tube which can telescope even when the trailer is fully loaded at 250t. Turning radius is variable between 11m and 15m.

Both axles of the counterweight trailer are steered electronically from the crane cabin. The steering enables the trailer to be set for towed travel, circular travel or travel parallel to the crawler crane. The trailer automatically follows the crane in any direction, says the manufacturer.

The trailer, when unloaded, weighs 26t and measures 2.5m wide by 2.6m high by 8.5m long. Erection and dismantling is aided by two hydraulic jacks, which also relieve pressure on the 12 standard pneumatic 16.00 R25 tyres when changing the driving direction with total counterweight.

The LR 1400/1 itself was launched by Liebherr-Werk Ehingen at Bauma in March 1998. By October, 14 units had been sold, including five to Van Seumeren of Holland. All the Van Seumeren crawlers, of which two have already been delivered and three are to be delivered early in 1999, are being equipped with the telescoping counterweight trailer.

The system means that when equipped with an 84m main boom, a 77m lattice jib and 250t derrick counterweight, the crane can lift more than 22t to a height of 158m and more than 9t at a radius of 92m.