Drive train & power supply
The truck is powered by an electric synchronous motor that drives the first and third axles. The power supply comes from the battery pack or directly from the diesel generator. There is also a hybrid propulsion option, where both energy sources are used. When the truck is braked, the energy released is recovered in the battery. Whether the crane is travelling or in operation, its energy supply can come from three different sources:
Fully electrical (battery)
Hybrid (combination of generator and battery)
3 in 1 Cabin
The SK487-AT3 is the first mobile tower crane to be fitted with a single cabin. The cabin functions as a truck cabin, lift cabin and crane cabin all in one. In crane mode, the cabin can be moved to any desired height, always solidly connected to the crane, so the operator maintains full feeling and control over the crane at all times. The cabin is very spacious, with a large window area to optimise not only visibility and comfort but also safety. The cabin’s internal dimensions are 970 x 1670 x 3130.
IFP outrigger technology ®
To make even better use of power, Spierings has developed an entirely new and revolutionary outrigger system called “Intelligent Foot Print Outrigger Technology®”. This gives the crane an outrigger width of 7.25 metres with a chassis that is just 2.50 metres wide. The system makes use of a number of outrigger beams that are locked at the top with a sliding support beam on the underside that exerts a horizontal pulling force towards the chassis. Together with a lighter structure, this provides 20% more outrigger area to enhance the crane’s capacity. Thanks to the IFP Outrigger Technology®, the crane has the ability to automatically calculate the lifting chart per outrigger, with variable widths, and apply it to the load moment protection system.
Extendible jib technology
In mobile tower cranes, the radius of the crane is often one of the essential factors. Spierings developed the extendible jib technology to increase the radius even further. This new development was first used on the SK1265-AT6 crane, achieving a radius of 60 meters with a 1.7-ton maximum tip load. The extendible jib delivers an extra eight metres of jib length. The jib itself becomes wider after it is extended, making the width of the extendible jib the same as that of the existing jib section. This technology has also been implemented on the SK2400-AT7 and SK2400-R models. A modified version of the extendible jib has also been used on the SK597-AT4 and SK487-AT3 cranes. With this type of crane, an extra four metres of jib length is obtained. Furthermore, the transition between the jibs is seamless due to the two carbon sections that rotate at the same time the jib is being interlocked and adopt the same dimensions as the rest of the jib. These cranes also achieve a maximum tip load of 1.7 tons.
Steel pads with auxiliary crane
Spierings developed its steel support pads with an auxiliary crane to guarantee maximum safety and the “one-man” concept. The operator can position the pads quickly and simply by using an auxiliary crane. Once the crane’s outriggers have been positioned and the tower has been raised, the operator can use the auxiliary crane to position the steels pads at the outrigger feet. The steel pads are carried on the truck’s rear box, so no additional transport or manpower is required. The pads are made from high-quality steel, which makes them very tough and yet lightweight. The pads are galvanised as standard.
Hydraulic crane movements
All crane movement commands are hydraulically proportional. This makes it easy to operate the crane and delivers maximum precision and efficiency. Numerous refinements mean that the design is of an exceptionally high quality and the crane offers unrivalled control and fine-tuned accuracy, allowing precise, rapid movements. The upper engine drives three hydraulic pumps for crane operations, with no interference from any inefficient components.