Light alloy rims that can be individually designed and enhance the look of any car - the Swiss rim manufacturer Ronal Group goes to great lengths to achieve this: polishing, painting, bright turning and milling create elegant surfaces. MCR (Multi Color Rim) and pad printing add color effects to the wheel. After the final quality control, the rims are packaged and shipped. The Ronal Group supplies OEMs directly. The wheels for the aftermarket are distributed by the logistics and distribution company Ronlog in Forst, 25 kilometers north of Karlsruhe.

Healthier handling

Since 2016, up to one million rims per year have been passing through the logistics center with space for 300,000 products. 45 employees take care of the 14- to 23-inch wheels. "We use vacuum tube lifters from a weight of ten kilograms - since 2018 also for handling the individual rims," says Peter Kuppinger, Team Leader Packaging and Quality at Ronlog. A total of eight vacuum tube lifters Jumbo from J. Schmalz make both packing and order picking easier for the employees. The rims are delivered and stored on pallets. Five to six employees place the individual items in boxes on protective foam inserts according to customer orders. "A 14-inch aluminum rim weighs six to seven kilograms. They are still packed by hand today. Until three years ago, however, we also had to lift the large 20-kilogram rims with pure muscle power and place them in the boxes. With 600 parts per day, that can quickly put a strain on your back," explains Kuppinger. In 2018, Ronlog was therefore looking for a solution that would make the work processes more ergonomic and thus protect the health of the employees.

Testing in practice

Schmalz installed a smooth-running aluminum column-mounted slewing crane and a JumboFlex vacuum tube lifter. "The challenge lay in choosing the right gripper," said Kuppinger. "Our rims must not get a single scratch. In addition, we naturally have many different designs with wide or narrow struts, with grooves or attached applications. A standard vacuum gripper reaches its limits here." Although Schmalz did not yet have a rim gripper in its range at the time, it was working on a solution that would enable the sensitive products to be safely picked up and placed in the cartons. "We were allowed to get involved in the development project as a field test partner and tested various gripper variants with different functional principles - both mechanical and pneumatic," explains the team leader.

Schmalz has now launched the result: a wheel rim gripper made of sturdy plastic with an amazingly simple and functional mechanism. As soon as the user has plunged the gripper into the central wheel hub opening and given the JumboFlex the command to lift up, a folding mechanism locks the system. The rim can be moved horizontally with one hand and placed in the foam bed in a targeted manner. As soon as there is no more weight on the vacuum tube lifter, the lower movable load-bearing element of the gripper folds down again and the operator can carefully guide it out of the hub. Schmalz has rounded off all edges so that no sharp edges can damage the polished, painted or polished rims. "The result of several years of development work is impressive," praises Kuppinger. "It significantly simplifies handling and demonstrably reduces the workload for employees."

Ergonomic right up to the loading edge

Once the boxes are closed, the danger is averted - at least from scratches. Nevertheless, the heavy boxes still have to be lifted, sorted and stacked before loading. The largest packages measure 500 x 500 x 300 millimeters. They weigh up to 20 kilograms. This is why the logistics company wants to protect the health of its employees here too: "We stipulate the use of lifting aids for loads of twelve kilograms or more, which is how much a 17-inch rim weighs, for example." Ronlog has therefore set up column-mounted slewing cranes at the various stations in the packaging and picking area, to which JumboFlex vacuum tube lifters with multi-grippers are attached. This gripper, which was only developed and launched on the market in 2020, is particularly lightweight thanks to the 3D printing process and can safely handle cartons of different sizes and qualities - without changing grippers and with a minimum occupancy rate of just 75% of the suction surface.

"In the picking area, the recent conversion of the roller conveyor to a main and secondary conveyor meant that a larger working area had to be covered by the crane solution used," reveals the team leader. An aluminum suspension crane system provided the necessary freedom of movement. The smooth-running aluminum Schmalz crane systems are impressive because they support ergonomic and fatigue-free handling of the loads. Two JumboErgo vacuum tube lifters are used here as lifting aids. They pick up cartons and double cartons weighing up to 25 kilograms from the roller conveyor and place them safely on the shipping pallet. The vacuum lifters are equipped with long, movable operating handles that allow cartons to be stacked up to a height of 2.30 meters. This corresponds to the maximum possible loading height of pallets for transportation by truck. "The use of vacuum lifting technology across the entire flow of goods pays off for us," summarizes Kuppinger. "Our employees are fitter and are absent much less often due to aching joints."

The article appeared in materialfluss 11-12/21.