Torque-resistant cables for vertical order pickers of up to twelve meters

Profile

• What was required: Resilient energy and signal cable via a movable mast with several guide rollers to the cabin of an order picking device
• Requirements: Space-saving guidance of electrical and hydraulic cables, application using the deflection principle for long cable lengths
• Product used: chainflex cables
• Industry: Material handling
• Success for the customer: Durable cable solution for the challenging geometry of the mast and guide roller

About vertical order pickers: Still is one of the world's largest manufacturers of forklift trucks. The task of the EK-X series of vertical order pickers is to move to the pallets in the narrow aisles of a high-bay warehouse from which the driver removes individual cartons. The vertical order pickers can reach heights of up to 12 metres and, thanks to their modular design, can be perfectly adapted to individual applications. For example, buyers can choose from a range of cabins, lifting masts, control panels and battery systems, and customised options are also available.

Problem

Still has been using the deflection principle for cable guidance in smaller order picking devices for some time now, and it has proven itself. For the EK-X series, the side guide for the roller was improved slightly due to the longer cable lengths – but initial tests quickly showed that this solution unfortunately did not work here. Volker Haspel, responsible for electrical development at Kion Systems: "The cables we normally use twisted and looked like corkscrews. Shortly afterwards, they failed in testing. Testing such cables is a complex task in itself. They perform relative movements in the lift mast and high dynamics occur when the order pickers are moving. In addition, the tensile force that occurs here, unlike with energy chain cables, must be taken into account."

Solution

Tests in the laboratories of both companies showed that the special chainflex cable design with cores wound in bundles holds up very well, even on the rollers. The cores are first wound in bundles, which are then stranded around a core element with a small pitch length. This core element not only serves as a filler, but is also designed as a strain relief element. The result is very similar in appearance to a steel cable. To further support this strong stranding structure, a jacket is extruded under pressure to guide the cores in the longitudinal direction. All these measures minimise the forces acting on the cable and maintain its structure.