Vertical cable guidance in storage and retrieval units

What was needed: Vertical energy supply on the mast for the SSI Exyz series storage and retrieval units from SSI Schäfer

Requirements: Low wear and maintenance-free, fail-safe

Industry: Material handling

Success for the customer: The guidelok slimline P e-chain with a special guide trough reliably guides the SRU cables even at speeds of up to five meters per second. It prevents impact and rocking movements of the energy supply system, prevents wear provides the smooth operation of the system. The guidelok system has now been installed in over 2,000 SRUs and there have been no issues to date.

High-bay warehouses with heights up to 45 meters are expected to operate in tropical environments as well as deep freeze conditions with temperatures as low as -30°C (-22F°). This can pose a challenge for storage and retrieval units (SRUs). Storage and retrieval units such as the SSI Exyz from SSI Schäfer must withstand these conditions in continuous operation.

The SSI Exyz (pronounced "Axis") has been on the market for many years and has become a trusted solution in the logistics industry. During its development, special attention was given to the power supply system for vertical movement—a critical factor in ensuring long-term system reliability. While conductor lines are a cost-effective solution, their exposed contacts and design often make them maintenance-intensive and prone to faults. SSI Schäfer had firsthand experience with these limitations and sought a more reliable alternative.

A key objective in the development of the SSI Exyz was therefore to create a dependable, long-lasting energy supply for the vertical axis. Even before the Exyz storage and retrieval unit (SRU) was introduced, SSI Schäfer had focused on cable management systems capable of operating maintenance-free for many years. However, the company also recognized the drawbacks of traditional free-hanging energy chains, which are susceptible to wear and can generate significant operating noise.

Because SSI Schäfer supplies systems worldwide, the solution needed to deliver consistent performance regardless of installation conditions. The result was a guided cable management system designed to provide stable operation, minimize wear, and ensure reliable energy transmission over the long term.

For the SSI Exyz, the development team at SSI Schäfer also decided to install an igus® guidelok slimline P energy chain a as standard instead of a conductor line for the vertical energy supply on the mast. The system consists of a guide trough with special spring elements. The fixing mechanism built into the guide trough of the guidelok guides the chain securely in the trough during acceleration of the SRU. The guide trough prevents the e-chain from swinging when accelerating or decelerating, allowing the e-chain to run smoothly. This fits in particularly well with the Exyz pallet truck guide concept, which is designed for extremely smooth running.

Another advantage: As uncontrolled impact and rocking movements can be prevented. Unlike free-hanging chains, the signs of wear associated with vibrations are prevented. The system therefore works safely even at speeds of up to five meters per second, which are now standard in many SRUs.

Installation has also been significantly simplified with the latest development stage of the guidelok energy chain. While the guide rails for the energy chain still had to be screwed into place on the previous model, they are now only inserted into plastic holders. This saves fitters a large part of the installation time and also significantly reduces the weight. If servicing is required, the chain can still be accessed quickly at any time.

The energy chain is supplied to SSI Schäfer with all the necessary components ready for installation. The guidelok models installed in over 2,000 SRUs have only been replaced twice so far. In both cases, external force was the reason, but there were no complaints from regular operation.