Curved fences for part alignment

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 [14] 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 an individual fence, consisting of a straight slanted section followed by an optimal curved tail. The straight section selectively 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.