Improved safety

Is it possible to work safely beneath suspended loads? Together with the hot-galvanising company Helling & Neuhaus and the industrial employers’ mutual insurance association, a solution has been developed that allows workers to remain beneath suspended loads. The lifting and drop sections on two conveyor lines are each equipped with two Demag double chain hoists that are connected to each other by means of a tandem control system. This concept, which satisfies the requirements of BGV D8 Plus hoists in full, will also set a precedent in other applications and provide for maximum safety.

The project

New concept for suspended loads in production 

Special safety requirements, which are laid down in the BGV D8 regulation, have to be met wherever people are present beneath suspended loads. The applications for which these increased design and safety requirements have to be met also include production facilities for the treatment of metal surfaces. Even though the production sequences are performed automatically in most cases, the material to be coated is often attached to the spreaders and removed at the end of the circuit by hand. For this reason, it must be possible for workers to remain beneath the loads in order to attach and remove the individual parts.

This is also the case at the hot-galvanising company Helling und Neuhaus.

For this solution, four pick-up and deposit stations were each equipped with two Demag LDC-D double chain hoists, which are also connected to each other by means of a tandem control system. LDC-D units were developed on the basis of the proven DC chain hoist range for transporting long material and for spreader applications. The chain hoist drives a separate lifting block that has its own chain drive via a connecting shaft. Both chain lead-offs are rigidly connected to each other by a common frame, the hooks are spaced 800 mm apart. Due to high load-dependent lifting speeds of up to 24 m/min, LDC-D units are also designed for high handling rates. In addition, they provide for a longer chain service life as a result of the reduced polygon effect, since there are no additional chain return sprockets.

High safety and reliability for lifting and lowering

The four attachment and removal stations employed at Helling & Neuhaus consist of 6 m-long I-beam sections, which are integrated into the conveyor track. When one of the motor-driven spreader trolleys reaches one of these stations, the spreader is first held by a locking arrangement. The track profile sections are held by two double chain hoists and lowered to allow the parts to be attached for the galvanising process.

Two chain lead-offs also double the level of safety. Synchronised operation of the hoists is also monitored by the tandem control system. This arrangement ensures that the four hooks are always level with each other during lifting and lowering motions. Even if one of the chains were to break, the load bar would remain in a stable position. The lifting and lowering stations operate with several secondary safety features – also thanks to a double brake system – to ensure the highest possible safety and reliability for the workers.

Intelligent control system integration 

The tandem control system of each trolley travel unit is integrated into the control concept of the overall material flow system, i.e. it is connected to the intelligent control system of the monorail circuits. To ensure that this control system receives reliable signals from the trolleys, additional limit switches were installed for the hook positions of the chain hoists.

This system has enabled Helling & Neuhaus to achieve a safe and efficient method to implement a D8 Plus hoist unit that meets the provisions of the BGV D8 regulations and permits staff to work beneath the drop sections of the monorail circuits. The technical solution is based on the use of Demag standard components from the modular construction kit which also meet the design requirements of galvanising applications. For this variant, the chain hoists are provided with additional corrosion protection.

Solution not only for surface finishing

The operating availability of the lifting and drop sections is a crucial factor for Helling & Neuhaus . This requirement is also satisfied, as the new system has been running without any problems since it was installed. The conveying and lifting equipment that satisfies the BGV D8 Plus requirements is not only of interest for companies in the surface finishing sector, but also serves as an example that can be utilised for applications in other industries.

About Helling und Neuhaus

Helling & Neuhaus GmbH, based in Gütersloh, Germany is specialised in hot-dip galvanising. The company is part of the Seppeler Group, which operates a total of nine galvanising plants in the northern half of Germany and three in Poland. The individual locations focus on different parts of the product range. As a hot-dip galvanising plant for universal demand, Helling & Neuhaus treats a wide variety of components, ranging from small bolts to metal parts measuring up to six metres in length.