Patent ID: 8813943

Claim:
A positive displacement sorter, comprising: a plurality of interconnected parallel slats defining an endless web that travels in a longitudinal direction, said web having upper and lower runs and transition sections between said upper and lower runs, an upper surface of said upper run of said web defining an article-conveying surface; a plurality of pusher shoes, each of said shoes travelling along at least one of said slats in order to laterally displace articles on said conveying surface, each of said shoes having a diverting member extending below said conveying surface; a plurality of diverting rails below said conveying surface, each of said diverting rails capable of engaging said diverting member to cause the associated shoe to travel laterally to divert an article; a plurality of diverters, each for selectively diverting at least one of said diverting members from a non-diverting path extending longitudinally along said sorter to one of said diverting rails in a diverting state; and a propulsion system propelling said web, said propulsion system including at least one drive assembly engaging a driven surface comprising a lower surface of said upper run or an upper surface of said lower run, wherein said at least one drive assembly includes a belt having a belt surface engaging said driven surface, said belt surface adapted to resist slippage between said belt and said driven surface, wherein said belt surface comprises a plurality of slat drive cogs, each adapted to engage a vertical surface of one of said slats, wherein at least some of said slats have a groove formed in that slat and wherein said slat drive cogs comprise a set of first slat drive cogs each adapted to engage an interface between adjacent ones of said slats and a set of second slat drive cogs each adapted to engage said groove in one of said slats.