Patent ID: 7863536

Claim:
An article sortation system comprising: an endless conveying path having a first side and a second side, said first side being generally opposite said second side; a plurality of transport units which are movable along said conveying path, each of said transport units having article support capability; a first induction station at said first side of said conveying path; a second induction station at said second side of said conveying path, said first and second induction stations being operable to receive articles in a random order and to move the received articles toward said conveying path in the order in which the articles are received by said first and second induction stations; a plurality of discharge stations, at least one of said discharge stations being at each of said first and second sides of said conveying path, said plurality of transport units being operable to receive articles from said first and second induction station and to unload articles to said discharge stations; and a control, said control being responsive to said first and second induction stations to determine a blocking condition between the articles, said blocking condition comprising an interference between two articles based on a destination of the two articles and the side of the conveying path or transport unit at which the two articles are positioned, wherein said control determines an appropriate discharge station for the articles and controls said first and second induction stations such that articles are loaded or loading is delayed from said first and second induction stations onto said transport units and wherein said control controls said transport units to unload the loaded articles from said transport units to said appropriate discharge station in response to the destination of the articles and said blocking condition between a respective pair of articles.