Bauma 2016

High-wire performers

Posted on 07 June 2016 by Wolfgang Stolba, Images by Robert Hack

Mobile cranes are serious contenders in the world of industrial and high-rise construction previously dominated by heavy cranes.

Mobile cranes just keep on gaining ground. With ever-increasing load capabilities, lifting heights up to 100 meters and up to two engines, they are now serious contenders in the world of industrial and high-rise construction previously dominated by heavy cranes. MTU is a leading supplier in this growth sector. Prestigious construction machine builders like Terex, Liebherr and Manitowoc purchase many hundreds of Series 1000 and Series 1500 engines every year. TADANO, a German-Japanese manufacturer based in Lauf an der Pegnitz near Nuremberg, buys only MTU drive systems. The company has been working closely with MTU for many years.

The TADANO location in Lauf an der Pegnitz in Bavaria is not short of production halls, and it needs them all. The 820-strong workforce produces several hundred mobile cranes every year and the trend is up. With more than 86 international sales and service centers and twenty branch locations, TADANO is a major player in the mobile crane and lifting technology sector. The location in Lauf specializes in all-terrain cranes – vehicles that are at home both on and off the highway. They are ideal for erecting communications towers and power transmission masts, for constructing power plants and container terminals and for rescue and recovery assignments as well as inspection and monitoring work.

When these mobile cranes take to the road, they can really move. The multi-axle giants reach up to 85 kph on highways and non-urban roads and have no problem negotiating the rough terrain and slopes that connect with the construction sites. The engines have to deliver the power to shift vehicles weighing up to 96 tonnes. By comparison: a standard freight transport truck weighs up to 40 tonnes. Once on site, mobile cranes can be secured and ready for action far faster than mobile crawler cranes or stationary lattice-boom cranes. Under frequently difficult on-site conditions, they perform truly amazing high-wire feats: they can shift loads weighing many tonnes with the utmost precision and set them down again with absolute accuracy. The process is only possible thanks to the sophisticated interplay of high-quality assemblies from engine, hydraulics and boom technology through to automation systems.  One project currently underway involves the replacement of the 40-meter high, 530-meter long Emskirchen railway bridge in Lower Bavaria that started at the beginning of the year with support from a TADANO ATF 220G-5. Frequent changes of position, restricted working space in the Aurach Valley and the inclines approaching the bridge piers made serious demands on undercarriage maneuverability as well as on the precision and elasticity of the superstructure and boom. In some cases, sections of old steel girders had to be moved by telescoping under load, i.e. by extending and retracting the unlocked telescopic boom with a load weighing several tonnes suspended on the hook.

Mobile cranes involve an immense amount of high-tech: “Our specialists are constantly at work identifying and getting rid of every single gram of excess steel on the undercarriage and superstructure. Any weight we save is invested in developing the travel and crane functions,” said Ulrich Mahler, development engineer at TADANO. The process must also ensure that the permissible total weight of 12 tonnes per axle in travel mode is never exceeded. “Chassis weight has been optimized to the point where only highly specialized welding techniques are capable of joining the components safely,” said Mahler. And these vehicles incorporate a great deal more sophisticated technology. During crane operation, the special-purpose axles can take loads up to 30 tonnes. Retarded rear-axle steering prevents excessive tail-end swing during maneuvering. An additional, non-wearing, hydrodynamic retarder ensures maximum braking safety. And taken overall, safety is priority number one. Sensors constantly monitor load and angle limits. A ‘lift adjuster’ ensures that loads are taken up carefully and without swing and the soft-stop function gently brakes the crane boom before it reaches the limit of its working radius. Features like these make it patently obvious that mobile crane development has long been an area for specialists only and that it requires a lot of them – for hydraulics, electrics, electronics, braking technology, statics, mechanical engineering and materials technology.

The manufacturer’s new and innovative flagship is the ATF 600G-8. The vehicle made its debut in 2015 and was also showcased at the ‘bauma’ exhibition in April 2016. The 96-tonne, 8-axle vehicle can lift 600 tonnes and its 56-meter long boom extends up to 90 meters. One special feature is that the boom is reinforced by two lateral telescopic tubes that provide outstanding flexural and torsional rigidity. This triple-boom system obviates the need for bracing units, making significant savings in terms of both time and money.  The design also makes the crane easier to deploy in restricted spaces. An electronic outrigger base monitoring system ensures optimum crane performance even in situations where it is not possible to fully extend all the outrigger bases. Sensors measure the respective extended lengths of all four outriggers and the position of the superstructure. On the basis of these data, the central crane control system determines the maximum permissible load capacity. 

Dual-engine concept means multiple benefits

The ATF 600G-8 mobile crane has two separate engines: an MTU Series 1500 engine (625 PS) for the undercarriage and a Series 1000 unit (354 PS) for the superstructure. Both engines meet the latest Euromot 4/Tier 4 final exhaust emissions specifications. The TADANO portfolio includes eleven model series with all but the two smallest mobile cranes being powered by two MTU engines each. The dual-engine concept lies at the core of the company’s product philosophy. The use of the smaller superstructure engine means significant fuel savings during crane operation. At the same time, it prolongs the service life of the propulsion engine and facilitates longer overall servicing intervals. The system also does away with fault-prone rotary joints for electric and hydraulic power transmission. If the battery fails for any reason, the second engine is always available to provide auxiliary starting capacity.
All these advantages add up to rising annual production figures and commercial success – and that is why TADANO is investing heavily in the Lauf location. New developments include a new test facility, a logistics and training center and the trials site in Pegnitz. TADANO has been part of the Japanese TADANO Ltd. Group since 1990 and during that time, the Lauf facility has become a center of excellence for all-terrain cranes. Both companies view the take-over by TADANO as a stroke of good fortune: “TADANO benefits from our innovations whilst we can continue to build on our already well-established reputation for quality as well as gaining additional benefit from the exceptional Japanese quality culture,” said Ulrich Mahler. 

High-quality production

No components are manufactured in Lauf. Production concentrates purely on the assembly process. It is clear at a glance that the facility focuses on high-volume production. Two 150-meter long assembly lines with around 30 individual stations run straight through the main assembly hall. On the right is the undercarriage assembly line; the slightly shorter superstructure line is on the left.

The assembly process starts when the steel structures for the undercarriage are loaded on turntables. The individual assemblies are then added: hydraulics, pneumatics, cable harness and the air network structure for the pneumatics system. Then come the pipelines, the axles and the MTU engine with the gearbox and cooling system. The driver’s cab is then fitted and the cables are connected up. Finally, the superstructure and undercarriage are married.  The booms are installed on the superstructure in a separate hall.

Overall, the process combines high-volume production with extremely high quality levels. Consequently, initial inspection targets individual assemblies during the assembly process rather than the finished mobile cranes on completion. Inspection stations are fully integrated in the assembly lines. The same applies for the first engine test runs. As soon as they have been fitted in their open frames, they are connected up to heavy hose lines for intake air and exhaust gas and are started up on the assembly line. Electronic technology has likewise become a major element in mobile crane construction. Software is loaded for the two screens in the driver’s cab to allow numerous functions to be displayed and monitored while the cab is still on the assembly line. Despite all this, the company still places at least as much emphasis on robust assemblies that work reliably as it does on sophisticated automation systems. “We are interested in progress, but not at any price,” declared Ulrich Mahler.  That is why, in case of doubt, robust electric designs for components such as fittings and displays are always given preference over more delicate electronic equipment.

TADANO – A Nuremberg company with a long tradition

TADANO has been part of the Japanese TADANO Group since 1990. Its roots stretch back to 1845 when Julius Braun laid the foundations for the company with his foundry in Nuremberg. The Justus Braun Premier-Werke built fire-fighting vehicles – initially as horse-drawn models and then, from 1890, as steam-powered vehicles. 1910 saw the development of a ‘hybrid drive’ incorporating a gasoline engine, a dynamo and an electric wheel-hub motor. The facility in Lauf an der Pegnitz came into being in 1943. From 1949, it produced freight trucks, garbage trucks, crawler-tractors and, later, heavy haulage trucks and tractor units with mobile crane chassis following during the 1960s. The first all-terrain cranes with load capacities up to 50 tonnes appeared from 1985. Following take-over by Japanese manufacturer TADANO, the product range was extended significantly to include cranes with load capabilities up to 360 tonnes.

Point of Contact

Dietmar Wetzel
+49(7541)90 7033
+49 7541 90 7033

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