Rare Earth Magnet For Supermarket Cages
Industry: Steel Fabrications
A leading manufacturer of goods trolley cages was approached by his customer to resolve a re-curring problem with breakage of the bottom “lift up shelf. “ This was happening mainly when trolley cages were being stored together after use. The current method was to manually lift the bottom shelf, hold and secure in position by tying off, so the next trolley could be stored. The human error was to try and force the cage into position by brute strength, which eventually sprained and buckled, leaving the trolley cage un-useable. Cost involved in time and scrap was becoming excessive. We were then approached by the trolley manufacturer for a solution to the problem.
Further research into the operator error, disclosed that the operators were constantly trying to position the shelves with their feet rather than by tying back the shelf. Following discussions with the customer we agreed it would be possible to secure the bottom shelf in the vertical position by magnetic means.
Neodymium Rectangular Bar Magnets
Trials were carried out using Neodymium rectangular bar magnets working across an air gap, but ensuring there was enough holding force to secure the shelf in the upright position. Calculations were carried out and holding forces determined at various air gaps when a suitable holding force was determined, actual physical trials on the shop floor by operators were undertaken. Once an adequate holding force was determined the magnets were plastic injection molded (with the predetermined operating air gap). The solution saved significant time on labour and costs of scrapped trolleys.