A Method to Determine Allowable Speed for a Unit Load in a Pallet Flow Rack

Abstract

Pallet flow rack are widely used in intralogistics to maximize warehouse capacity and to reduce the travel by fork-lifts. However, the use of pallet flow racks is associated with increased danger due to the use of gravity conveyors in their design. For this purpose, the gravity conveyors of pallet flow rack have a two safety elements – brake rollers and a stopping mechanism with pallet separator, which are working as a system. Brake rollers limit the speed of pallets, while the stopping mechanism allows exuding a pressure on the unloading pallet from the following behind it. A pallet should have such a speed, controlled by the brake rollers, so that it could be stopped by a stopping mechanism without damaging it. Based on the Cox impact theory, an original method for determining the allowable speed of a pallet in a pallet flow rack is proposed. The method ensures safe operation of the stopping mechanism with pallet separator and takes into account the mechanical properties and design parameters of the pallet separator stopper. A calculation example is provided for the most commonly used types of pallets – Euro pallet (1200 mm × 800 mm) and Industrial pallet (1200 mm × 1000 mm). The obtained results agree well with the pallet speed range of 0.2 to 0.3 m/s recommended by the manufacturers of pallet flow racks.

Pallet Motion on a Magnetic Brake Roller

“…For developing the MM, the approaches used for centrifugal friction rollers [10,15] and eddy current braking devices [16,17] were utilised. Fig.…”

“…As there is no slip between the pallet and the MBR (based on the studies conducted in [10,15]), the MBR body rotation speed 𝑛 𝑇 is…”

“…2), 𝐷 𝑀𝑃 = 89 mm and 𝐷 𝐵𝐻 = 83 mm, and a two-stage multiplier with a gear ratio of 24 is used based on the analysis conducted in [31]. The efficiency 𝜂 𝑀𝑃 of MBR can be calculated similarly to that of the centrifugal friction roller [10,15]. In this case, according to experimental data [30], the coefficient of magnetic viscosity is 𝛽 1 = 0.113 N s/m for the considered MBR construction (Fig.…”

“…The rollers are installed along the rack at a certain interval. Brake rollers are used to limit the speed of the pallet with cargo (further referred to simply as a pallet) [10]. In GFRs, centrifugal friction rollers are the most common.…”

Experimental evaluation of the load capacity of the rollers of gravity conveyors for pallets

“…Íåñóùèå ðîëèêè (äàëåå ÍÐ) íàðÿäó ñ òîðìîçíûìè ðîëèêàìè è óñòðîéñòâîì îñòàíîâêè è ðàçäåëåíèÿ ïàëåò ÿâëÿþòñÿ îäíèì èç îñíîâíûõ ýëåìåíòîâ ãðàâèòàöèîííûõ ðîëèêîâûõ êîíâåéåðîâ (äàëåå ÃÐÊ) äëÿ ïàëåò, êîòîðûå íàøëè øèðîêîå ïðèìåíåíèå â ñêëàäñêîé èíòðàëîãèñòèêå êàê îäèí èç òèïîâûõ ìîäóëåé, ïðåäíàçíà÷åííûõ äëÿ õðàíåíèÿ è òðàíñïîðòèðîâêè ãðóçîâ íà ïîääîíàõ [1,2,3].…”