Steerable rollers direct products

Tom Shelley reports on an ingenious method of steering goods passing along roller conveyors Inclined wheels are key to a novel roller conveyor that can be used to steer items passing over it. Unlike the wheels of a car, steering is achieved by rotating assemblies on which a whole line of wheels is mounted, and the mechanism looks as if it should be little more expensive than conventional roller conveyors. The idea has been invented by Adrian Marshall of Crafty Tech, whose rubber toroid, roll on gripper for handling sticky cakes and similar products was featured in the September 2002 edition of Eureka. Each wheel consists on an inclined hub, about which a rubber tyred wheel is free to rotate. Powering is by a friction drive, acting on the inside edges of the tyres from common drive shafts running through each line of hubs. The inclined hubs are mounted on off-centre support bars, which allow a line of wheel hubs to be rotated about an axis transverse to the direction of conveying. If the wheel hubs are inclined vertically, the direction of the interaction between load and wheel at the point of contact is in the direction of the conveyor. The conveyed item will then proceed straight along it. If, on the other hand, the hubs are inclined horizontally, the direction of the interaction at the point of contact will be at an angle to the direction of the conveyor, equal to the angle of inclination. If the wheel hubs are inclined in directions between vertical and horizontal, conveyed items will move at lesser angles to the direction of the conveyor. The idea presently exists as a working prototype demonstrator. Mr Marshall says that by employing assemblies of wheels with appropriate wheel inclination angles, roller beds can be configured to switch steering from left to right, from converge to diverge, or give an adjustable bias of product distribution to one side of a process, such as to achieve optimum loading of spiral freezers. In the handling of fragile good items, the idea offers many advantages over movable inclined barriers. It is also suitable for handling other delicate products and also offers a way of tensioning web material laterally. The Steerable Roller was one of a number of novel patented product handling solutions launched by Crafty Tech at the two day 'Excellence in Food Manufacture 2004 Conference held at PERA at Melton Mowbray in October. The demonstrator unit has wheels between 60mm and 65mm in diameter, suitable for light loads. Crafty Tech Pointers * Assemblies of inclined wheels on shafts allow items to be steered along a roller conveyor without the expense of making each wheel individually steerable * Items can be steered to left or right, from converge to diverge or used to give product distribution an adjustable bias * The idea exists in the form of a patented, working, demonstration prototype