Flexible energy chain for innovative cable robots in automated high-bay warehouses

• What was needed: e-spool® energy chain
• Requirements: With the fast horizontal, vertical and diagonal movements, the supply of the various cables poses a major problem that cannot be solved with conventional cable systems
• Industry: Material handling, storage and retrieval machines
• Success for the customer: The cable robot with igus®-energy chain and e-spool® demonstrates a well thought-out solution that enables effective storage and retrieval logistics and at the same time counteracts the disadvantage of increasingly heavy storage and retrieval machines

Problem
Tall shelving systems are very well suited to storing goods effectively in small spaces. They also allow the use of fully automated storage and retrieval machines. However, the conventional design has a disadvantage: The higher the shelves become, the heavier the storage and retrieval machines become due to the rigidity requirements. While the containers or goods being moved are often very lightweight, the stacker cranes can weigh up to two tonnes.
The winner of the 2014 igus® golden vector award is a cable robot that provides a solution to the weight problem. The robot, which is used in automated high-bay racking, was developed by the University of Duisburg-Essen. The system is based on a transport platform with a gripper that moves in space using eight parallel wire ropes. The major challenge that inevitably comes with this idea is that the rapid movements in three-dimensional space raise questions about the supply of energy, which can only be solved using a sophisticated system.

Solution
The biggest problem with the concept for this storage and retrieval unit was the fast movements that take place in 3-dimensional space. To prevent the abrupt horizontal, vertical and diagonal movements from creating a tangle of cables, all data and supply lines are routed in an igus ® e-chain®, which rolls up and down on an e-spool®. As an alternative to the cable drum, the e-spool® can be used gently and safely with energy chains and cables. It is used in particular when many different cables need to be routed in a confined space. A standard e-chain® is guided by a roller and, thanks to an integrated retaining spring, ensures that the energy supply system is always exactly the right length and tension. In the starting position, the e-chain® space-saving is completely rolled up. The twister band connects the reel to the shaft end block, which serves as an interface to the permanently installed cable.