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Advanced Engineering 2021

NEC Birmingham(B40 1NT)

03/11/2021 - 04/11/2021

Join us in our 12th and most important edition to date, as we invite engineers and management from all (more)

Managing cables through linear and rotary movement

A new concept in energy chains has been developed to provide a combination of rotary and linear movement. Mark Simms got to see it in action to understand the problems it addresses.

There are many new concepts that seem so obvious once you've seen them, that you wonder why nobody thought of it before. Certainly there are challenges to be addressed, but once you've overcome those then the leap to the next big idea is actually only a very small step. The trick is in identifying that new idea, spotting potential markets, and understanding the technical problems that it could solve.

In its e-spool energy chain system, Igus has just such a concept and just such a problem solver. It combines rotary and linear cable management systems to provide end-to-end cable connection on a self-retracting spool. Eliminating the need for slip rings and enabling different media (power, data, air, etc) to be combined, the e-spool is a reliable and dynamic alternative to conventional cable management approaches in some applications, and to typical cable drum approaches in others.

Central to the e-spool is the Igus twisterband rotating energy chain. The twisterband was developed to provide greater rotation (up to 7000 degrees in fact, depending on the number of layers) than could be achieved with existing cable management technologies. As an aside, the development of the twisterband is an interesting story. Igus had identified a need, and then set about looking at how it might be done.

According to Andreas Hermey, head of Igus' design department, inspiration actually came from a coiled telephone cable. Several design steps and many prototypes later, the twisterband was born. It provided a simple alternative to the complex and expensive rotary solutions that were usually needed to implement rotary movements in the smallest spaces to safely guide power, data and media.

Typical applications for the twisterband include robot arms, medical equipment, test equipment, aerospace, handling systems and more - anywhere that rotary unions are used. But one interesting application was a cable drum, to eliminate the need for slip rings. A slip ring is far from ideal in such applications. It can't accommodate fibre optic connections and pneumatic connections are very difficult to implement. Even in pure electrical connections, slip rings quickly wear and need regular replacement. But suppose you could combine a twisterband with a linear energy chain on a drum. That would address a whole raft of application requirements, providing a simple, robust and reliable alternative to conventional cable drum systems.

End-to-end connectivity
That's where the e-spool comes in - a next generation cable management system that provides reliable operation for a wide range of lifting applications. A standard Igus e-chain from the E2/000 series is routed via a spool, and a twisterband connects the spool with the shaft bracket, which serves as the interface to the permanently installed cables. Connection is end-to-end with no breaks and no need for slip rings. Cables for power, data, compressed air and fluids can be connected without interruption, and can be replaced or modified at any time. The chain is compactly wound up in its initial position and, thanks to an integrated return spring, the desired length and tension of the energy chain is always ensured.

Early applications for the e-spool have clearly demonstrated its effectiveness, and Igus sees potential in many areas where space is limited and in lifting applications where users are looking for space-saving energy chains, such as lifting platforms, cherry pickers, sorting lines, mobile cranes, platform applications, assembly or process cranes with grippers, or lighting rigs in the theatre industry. In addition, users can save space associated with storing the chain, as it has a smaller footprint than traditional zig zag chains that might be used in some of these applications.

Christian Barthen, global product manager for e-chains, comments: "We can have horizontal movement, vertical movement, and always have the chain return to its coiled position, which could be very important for applications where you don't want anything left in the direction of travel. Compared to zig zag applications, we can have much more dynamic movement: where a zig zag chain might allow a maximum speed of around 0.4m/sec, the e-spool offers deployment and retraction speeds up to 1m/sec."

With many successful implementations under its belt, Igus has now standardised the e-spool as a catalogue product available in three lengths, offering 4m, 7m and 14m of travel, with two inner chain widths of 80mm and 125mm enabling many different media and diameter cables to be housed in one drum. The twisterband TB30 can hold cables with diameters up to 16mm, and cables can be routed on one or both sides of the spool depending on individual customer requirements.

Igus director Justin Leonard comments: "We work closely with customers to develop innovative solutions, and the e-spool is yet another example. Robust and flexible, the e-spool energy chain is more durable than cable drums, and enables power, data and media cables to be combined in one compact, straightforward system.