Spierings Kranen of the Netherlands not only specialises but also – many customers believe – leads the field in the manufacture of truck-mounted folding tower cranes. Only Liebherr currently provides active competition in this market with its four-axle MK 80, although it remains to be seen what Arcomet does with Mobile Tower Cranes (formerly GIS Munsters) which it acquired last year.

Last month Spierings held an open day at its new factory in Oss to introduce its latest model to customers. The new SK 377-AT3 is a three-axle model that replaces the SK 365-AT3. Capacity and reach are both improved, the rating having been increased from 60 tm to 78 tm. The SK 377 has an extra 3m of jib and lifts 1.9t on the end of its 33m jib, compared with 1.7t at 30m on the older model. Maximum capacity is now 7.5t instead of 5t.

The Spierings range comprises a five-axle model, a four-axle and a three-axle model. The five-axle SK 598-AT5 and four-axle SK 488-AT4 have already had upgrades in recent years. The SK 377 represents completion of the new generation range. The older 365 differed from Spierings’ other cranes by having an open lattice tower. The 377, like the 488 and 598, has a tubular section tower instead of an open lattice design. Spierings says that the tubular style offers greater stability, with 1.8 times more torsional rigidity than an open tower of the same weight.

With just one button, the operator rigs the crane using the PLC into which Spierings has programmed all the steps. Set up time is 15 minutes, Spierings says. All crane motions are powered hydraulically for precise and flexible operation.

The chassis is an in-house design which is the only way to ensure maximum mobility and stability, Spierings says. Two of the three axles are driven by a 270kW DAF diesel engine. The truck is equipped as standard with an automatic levelling system, all power assisted steering on all axles, hydropneumatic suspension and ABS braking.

Other significant new features on the SK 377 include the option of a separate diesel engine for the crane upper. This improves fuel efficiency and makes for quieter operation as it is smaller than the one that drives the carrier.

A second optional feature that is new for the three-axle size is an elevator to take the operator up to the crane cabin. Standard equipment includes floodlights and remote control.

For several years the truck-mounted tower crane seemed an almost uniquely Dutch concept, but in recent years their popularity has begun to spread a little. And Spierings’ new crane looks like being just as popular as its bigger sisters. Already 26 units have been sold, and four of them have been delivered so far.