In intral­o­gis­tics, there is a wide range of solu­tions to satisfy the different require­ments for ware­house systems. If several pallets of a product need to be stored neatly and unmixed in a limited area, and if perma­nent avail­ability also plays a crucial role, a pallet flow rack is often the best solu­tion. Bito Lagertechnik has worked with ebm-papst to develop a new kind of racking system. With PROflow active, drive rollers nudge the pallets just enough to get them moving – and slow them down when needed.

The limits of gravity

“With PROflow active, we’ve taken a step beyond our stan­dard product range as far as pallet flow racks are concerned,” says Alexander Lang, product manager at Bito. Natural forces are usually called on to get things moving in such systems; pallets in flow racks are usually driven by gravity. They glide along an inclined plane with a slope of four percent from the loading to the unloading side – a proven tech­nique, but one that reaches its limits in some situ­a­tions.

Alexander Lang discusses the require­ments of the drive unit with Matthias Trenz.

Depending on what loads are being conveyed on the runways, prob­lems can arise when pallets don’t start moving or when they simply stop. That reduces product avail­ability. In addi­tion, newly loaded pallets can slide down the runway into ones that are stuck. The resulting colli­sions can damage sensi­tive goods. A braking system is installed at the unloading side of conven­tional flow racks to prevent the following pallets from pressing on the front pallet when a fork­lift removes it. But depending on how it is oper­ated, this mechan­ical assembly can cause prob­lems such as jammed pallets.

Bene­fits of drive rollers

So Bito chose to use drive rollers instead. They push the pallets along, prevent unwanted stops and can also slow them down. On the runway, they can keep pallets with sensi­tive goods apart so they move completely free of contact. There is no longer any need for the braking system; when the fork­lift oper­ator removes a pallet, the rollers move the pallets along the runway only after a prede­fined interval.
Besides increasing avail­ability and protecting the goods, PROflow active also makes it possible to cut the runway’s slope in half. That means more pallets can be stored in the same space. “There is no other flow rack on the market that works with a slope of only two percent,” says Lang.

System solu­tion, ready to install

The drive unit is the result of a joint devel­op­ment effort by Bito and ebm-papst. “Besides issues like size and power, one of Bito’s main ques­tions was how such a complex system could be inte­grated in a roller in the flow rack,” recalls Matthias Trenz, Market Manager Indus­trial Drive Tech­nology at ebm-papst. After many discus­sions, exper­i­ments and test phases, the drive solu­tion is avail­able as a ready-to-install cartridge – a plug & play system including a BLDC motor with elec­tronics, brake and trans­mis­sion, and the drive housing with roller cap and external cabling.

The drive unit by ebm-papst.

The drive motor is the ECI 63.20 K4, a brush­less 180-watt internal rotor motor with an inte­grated K4 controller and a brake module. “The system had to work without a control cabinet in every runway to keep the amount of cabling to a minimum,” says Trenz. The system’s intel­li­gence is distrib­uted in every roller, so the rack system can be expanded or reduced as needed.
The drive motor has a two-stage Performax® plan­e­tary gear system with a rugged combi­na­tion of plastic gears in the first stage and hard­ened steel gears in the second stage. In numerous tests, Bito and ebm-papst deter­mined the torque and gear reduc­tion required for the appli­ca­tion. Ulti­mately, they settled on a high gear reduc­tion of 102:1 for the optimum design.

Simple instal­la­tion

The drive system is inte­grated in a housing; the cable is routed out of the roller cap. “We adopted Bito’s roller contour with 80 millimeter diam­eter for the roller cap so it can simply be slipped over it and clamped in place,” explains Trenz.
The part­ners also devel­oped a compres­sion coupling that is placed on the drive shaft to provide force trans­mis­sion in the rollers. “The inte­grated drive system makes it very easy for us to install,” says Alexander Lang enthu­si­as­ti­cally. The complete rollers are installed in the side walls of the runway.

The drives are inte­grated into the rollers.

“We worked exten­sively with the entire system for PROflow active for a year and a half,” says Lang, “because we really wanted to get involved in this new tech­nology.” Its many successful vali­da­tions are proof of its high quality. The effort is worth it, because the flow rack has a lot of poten­tial. It can be used with various pack­aging and pallet types wher­ever sensi­tive goods need to be handled. The drives also prevent unwanted rocking during trans­port along the runway. “There’s no wobbling at all,” says Lang happily.

Learn more about the appli­ca­tions and bene­fits of PROflow active.