Abstract:
A method of controlling the flow of articles between upstream and downstream work stations which respectively produce and modify such articles so that both work stations can operate at the same rates or at different rates. A continuous flow of articles is received on various inbound tracks, and the continuous flow of articles is subdivided into individual arrays or groups of articles. In those instances wherein the down stream use rate is approximately or exactly equal to the upstream output rate, the groups of articles are transferred from inbound lanes or tracks directly to outbound lanes or tracks. In the cases wherein the supply rate or the demand rate, i. e. , the upstream or downstream machine rates are different, then groups of articles are periodically taken from inbound lanes and placed in transient storage or are taken from transient storage and placed in outbound lanes. The method includes moving transient storage receptacles, such as trays, to appropriately indexed positions so as to be aligned with the transfer head which picks up and deposits groups of articles. Also, the method includes adding or withdrawing trays, as needed, from magazines which hold full and empty trays, respectively.