Patent ID: 6799672
Filing Date: 2004-10-05
Classification: B65G

Abstract:
A sortation system comprising a plurality of transport units connected end to end to form a continuous train and mounted for movement along a track defining at intervals along its length destination ports at which items carried by each of the transport units may be selectively discharged under the control of a central control system, wherein the central control system comprises a radio frequency transmitter device through which control signals to the continuous train are transmitted, and the continuous train comprises a radio frequency receiver device for receiving the transmitted control signals and an on-board local controller for operating each of the transport units in response to a received control signal, wherein the central control system further comprises means for determining the current position of each transport unit relative to a fixed datum position on the track, which current positional data is periodically communicated to the on-board local controller, and the on-board local controller comprises means for extrapolating from the speed of the continuous train the distance travelled at any instant beyond the position previously communicated to it by the central control system.