Energy chains and cables for fail-safe storage and retrieval units from viastore

User report profile

• What was needed: energy chain, chainflex® cable
• Requirements: Safety during fast lifting movements and vibrations, deep-freeze resistance
• Industry: Mechanical engineering, small parts warehouses and storage and retrieval machines (RGBs)
• Success for the customer: Saving enormous process costs and minimising risk at the same time, as the components function perfectly, reliable and durable solutions that ensure high system availability and keep maintenance costs low

Within material handling, suppliers organise internal material flows using technical systems and software solutions. Automatic storage and retrieval machines (AS/RS), which move goods and store them in and retrieve them from the compartments of high-bay racking, are an elementary component of this.
Viastore, based in Stuttgart, has been developing and producing storage and retrieval machines for all types of warehouse, in all sizes and speed classes, since 1970 and differentiates between three basic types according to travelling speed and payload. The smallest system "Viaspeed" was specially designed for plastic containers and cartons and for a payload of up to 50 kg. With a travelling speed of 6 m/s and an acceleration of 3 m/s², it is highly dynamic. The RBG "Viaspeed XL", on the other hand, picks up loads of up to 300 kg and transports containers and trays. It has a travelling speed of up to 5 m/s and accelerates vertically at 2 m/s2. The system can also be used in temperatures from minus 40 degrees Celsius to plus 45 degrees Celsius. Finally, the most powerful storage and retrieval unit, Viapal, lifts pallets, pallet cages and other loads of up to three tonnes. The dynamic travel drive enables a travelling speed of 3 m/s and a vertical acceleration of 1.5 m/s2 .
These performances show that the demands on the systems are very high for all RGBs, whether small or large. Viastore offers solutions that are particularly dynamic and flexible and that enable more storage and retrieval as the number of parts and orders increases. Warehouse operators expect automated solutions to adapt to order processes and respond more quickly to peak times. They also demand reliable and durable solutions that ensure high system availability and keep maintenance costs low. Against this backdrop, it is crucial that all components in the devices, such as the energy management solution, also function perfectly under this high requirement profile and require little to no maintenance.

The maintenance-free polymer-energy chain and chainflex® cable from igus® fulfil these requirements today. They are mounted on the mast of the storage and retrieval machines in the lifting gear and supply the systems with energy and data like an umbilical cord. In particular, the rapid lifting movements and vibrations at high equipment heights or at high travelling speeds place an extremely high load on the cables. Conventional cables can often form corkscrew, which can lead to core rupture.
For this reason, igus® began developing special cables under the brand name chainflex® for dynamic use in energy chains back in 1989. A special feature is their specific bundle stranding design. Here, the cores are not stranded in layers around the centre of the cable, but are stranded together in three, four or five cores, which are then stranded together again to form an overall bundle. In addition, gusset-filling extruded inner sheaths fill the spaces between the cores. The effect: The stranding cannot untwist and each core is moved equally in the inner and outer radius during movement in the energy chain. One-sided stretching and compression, which often lead to broken cores or corkscrew, are a thing of the past.
Temperature-resistant cables are also important to Viastore for use in deep-freeze warehouses. They must be able to withstand small bend radii and millions of strokes at very low temperatures. Not only the design principle but also the materials used qualify the cables for continuous use in this application. For example, cables with specially developed, highly cold-flexible TPE outer sheath materials are used in particularly cold ambient conditions.
The wide range of cable types in the igus® programme was also important to the customer. Viastore can plan flexibly with 1,244 chainflex® cables - from control and servo cables to motor and robot cables through to bus, encoder and fibre optic cables.