Optimal Curved Fences for Part Alignment on a Belt

Abstract

In automated packing or assembly it is often necessary to bring randomly oriented parts into uniform alignment. Mechanical methods such as vibratory bowl feeders are often used for this purpose, although there is no theory for the systematic design of such feeders. A slanted “fence” attached to the stationary sides of a conveyor belt is also capable of orienting a stream of parts and a sequence of such fences has been shown [17] to function as a systematically designable linear parts feeder. A limitation of fence alignment is that once a part has left contact with a fence, its final orientation is confined to a narrow range of angles but is not unique. Here we consider the design of a single fence, consisting of a straight slanted section followed by an optimal curved tail. The straight section selectivity aligns certain edges of the part, while the curved tail preserves this alignment precisely as the part leaves contact with the fence. We have found the shortest tail which guarantees alignment. Optimal curved fences may be used individually for alignment of parts on a conveyor belt. They also lend themselves to systematic design of multi-fence linear parts feeders [8], [17].