Gantry crane for the storage yard

Neumüller GmbH has developed and manufactured an innovative gantry crane for the handling of building materials and machines – with hoists and drives from Demag. The crane is extremely robust and "weatherproof". At the same time, it works precisely and smartly: the synchronous running for the two 20-tonne wire rope hoists ensures that even 25-metre-long parts can be handled safely.

In the beginning, there was a very simple request: a 1:1 replacement of a fifty-year-old gantry crane on the open-air site of a precast concrete plant of the Berger Group in Vilshofen (Bavaria, Germany). The crane with a track width of 26 meters and a cantilever of around 8 meters on both sides and a lifting height of 10 meters has the task of handling building materials and machinery as well as loading and unloading trucks. The old crane had reached the end of its life cycle and since it had met the requirements of the Berger Group managers well until the very end, there was actually no reason to design anything other than an equal successor. Berger commissioned the crane experts at Neumüller GmbH in Thyrnau to do just that.

Crane construction with Demag components 

Neumüller first designed a box girder gantry crane, which was in fact essentially a "new edition" of the existing crane. In the subsequent project discussions with the Berger Group, however, a concept was developed on this basis that takes greater account of advances in crane technology and enables new crane functions.

It is no coincidence that Demag hoists and bogies are used for this purpose.

"As a manufacturer of cranes and other lifting and conveyor systems, we have been closely associated with Demag for more than thirty years." - Patrick Kumpfmüller, Project Engineer at Neumüller GmbH

DH hoists: Durable and flexible in use

Two DH rope hoists, each with a load capacity of 20 tonnes, enable the synchronous handling of heavy or particularly large loads. In this case, the two hoists are synchronized via the controller. Demag driving units with DRS 250 wheel blocks with Demag's own ZBA cylinder rotor engines are used as trolley chassis. Neumüller ordered these lift/chassis units from Demag as complete modules. 

According to Jörg Kunkel, Key Account Manager at Demag Cranes & Components, the Neumüller designers have made a very good choice with the EZDH 2050 double-girder trolleys: 

"The DH series is the most robust and durable wire rope hoist in the Demag range, even for outdoor use. And you can extend the already long service life of this series with a general overhaul." - Jörg Kunkel, Key Account Manager Demag

Best possible weather protection for crane and service personnel

In order not to reduce the long service life due to the design due to the effects of the weather, Demag supplied the two trolleys with the option of a rain protection roof. 

In addition, Neumüller has provided generously dimensioned "stations" with weather protection roofs and lateral weather protection for maintenance personnel at both ends of the crane girder.

"That was one of Berger's requirements: the service technicians should be able to work on the trolleys – whose drive components are heated, by the way – even in the rain." - Torsten Homm, Neumüller GmbH

The eight motors for the long travel as well as the trolley drives are all heated to prevent the installed runners from freezing in frosty temperatures.

An unusual crane design

For the steel construction – Neumüller's original core competence – the designers opted for a rather unusual design: The two portals each form a C-bracket that is guided over the double box girder of the crane bridge. This allows the cats to drive about eight meters beyond the track width of the crane runway to the end of the bridge. 

Andreas Baier, responsible for steel construction and welding technology: "This design not only offers maximum travel distances for the trolley, but also has the static advantage that the forces are absorbed evenly. This is demonstrated, among other things, by the fact that the deflection of the crane girder is very low at 20 mm at a full load of 40 tonnes."

Control: Dual and Coupled

With the gantry crane at Berger, Neumüller is also demonstrating a high level of expertise in control system construction, which was carried out in-house from the electrical planning onwards. The control system is divided into two air-conditioned control cabinets at the ends of the crane bridge, and a data cable takes care of synchronization. The crane is operated by radio remote control with joystick, and a tandem control system allows the safe transport of components up to 25 m long with both hoists.

Existing crane runway continues to be used, energy supply integrated

The crane uses the existing, approximately 100-meter-long crane runway, which only had to be cleaned. The DRS wheel blocks 500 from the Demag range move the crane continuously at up to 40 m/min. Trucks can be loaded and unloaded within the crane runway or under one of the two cantilevers: This ensures flexibility.

The existing cable tray will also continue to be used. 

"For safety reasons, we have dispensed with a permanently installed busbar, because any additional installation of energy supply components entails the risk of damage. The gutter, on the other hand - as decades of practice have shown - can be driven over by the truck without damaging the pipe. The deflection device of the cable drum ensures perfect cable routing." - Patrick Kumpfmüller, Neumüller GmbH

As an additional safety device, 3D scanners were integrated into the crane control system. It scans the road ahead of it and brings the crane to a safe stop if it detects an obstacle. This serves both machine and personal protection.

Conclusion: A good decision 

In the meantime, Neumüller has assembled and installed the new gantry crane, designed with Demag components, at the Berger Group's storage yard. And the operators are completely satisfied: the 50-year-old crane has been given an innovative and powerful successor 

Neumüller: Core competencies in steel construction and crane construction 

"We bring steel into shape": This is how Neumüller GmbH in Thyrnau near Passau introduces itself in a nutshell. The company, which has 30 employees, concentrates on the planning, manufacture and service of cranes, conveyor systems, lifting and turning towers and paternoster storage systems – and has been using Demag hoists and drive systems for more than 30 years. This expertise is in demand nationwide, but Neumüller has also built plants in Qatar and India. A current project has just been installed in Italy.