Article sorting systems are generally well known in the art and have become specialized to sort or separate specific types of articles. For example, U.S. Pat. Nos. 3,884,370 and 4,106,636 disclose systems for sorting letters and other types of flat articles. In U.S. Pat. No. 4,249,661, a system is disclosed for circulating objects around workstations so that such objects are available for carrying out different operations thereon. U.S. Pat. No. 4,766,547 discloses a system which is adapted for utilizing handling vehicles traveling along a conveyor network. The vehicles are self-propelled and controlled as to speed and other parameters by a computer system. The sorting system disclosed in U.S. Pat. No. 4,239,435 is especially adapted for sorting clean laundry which is mixed as to customers, types of laundry, delivery routes, etc.
Many sorting systems are inflexible, in that changes in the mode of sorting, or other parameters, are not easily modified. Other sorting systems are highly mechanical in nature, are complicated and are prone to damage and wear. Other systems are simply inefficient, in that they require complicated routing and sorting paths and equipment to accomplish a final arrangement of the articles. For example, in U.S. Pat. No. 4,239,435 identified above, the system labels locations on a looped conveyor and relates specific articles to sort to a location. If the loop has a capacity of 1000 garments the following problems can occur: 1) there is inefficient use of space because the garment density is very low, 2) the system cannot handle more than 1,000 garments in a lot and cannot be easily altered, 3) if an operator hanging garments misses one slot, the entire sort is thrown off and must be redone, 4) it takes nearly as long to sort 100 garments as 1000 garments, 5) and as the system capacity is expanded sorting time does not increase in a linear fashion making it very difficult to handle garment sort lots of, for example, 15,000 pieces.
Also, articles such as garments, are very difficult to identify and to achieve identification throughout the system so that effective sorting can be accomplished. This can be appreciated as the identity of a garment cannot simply be stamped on an outer visible surface thereof, but is often fixed at a location such as an inside cuff or collar, which is normally not readily visible. Also, when garments are hung on a conventional slick rail or screw conveyor, entanglement of either the garments or the garment hangers is a problem which frustrates the automatic identification and transport thereof.
From the foregoing, it can be seen that a need exists for an article sorting system which is highly flexible in that any sorting criteria can be carried out, and little space is required of such system. Another need exists for a sorting system especially well adapted for sorting garments and efficiently transporting the garments through the various paths of the sorting system. Another need exists for a flexible sorting system in which a wide variety of sorting paths can be utilized in a tradeoff between space and sorting time, while yet maintaining the same efficient sorting scheme.