Order pick system

Abstract

An automated storage and retrieval system (ASRS) wherein individual identical articles are disposed in vertical stacks stored in cells of movable totes. The totes are movable into and out of storage racks by an automated storage/retrieval vehicle. The ASRS includes an order picking system having at least two zones disposed along an order-collecting conveyor system. One zone picks low-demand articles, and the other zone employs high-speed dispensers which support plural upright stacks each containing identical high-demand articles for dispensing of such articles onto the conveyor system. A controller assigns order-collecting areas along the conveyor system so that picked or dispensed articles within the zones are deposited into a preassigned area for assembly of an order. The pick zone for low-demand articles preferably includes several subzones arranged serially of the conveyor system, and each subzone includes a picker mechanism which includes a picking head which moves longitudinally and transversely of the conveyor. A plurality of totes are supported adjacent and longitudinally along at least one side of the conveyor system, with the cells in each tote typically defining plural stacks of different articles all having a preassigned position relative to the movement of the picking head. The controller causes the picking head to remove a desired article from a specific cell for transfer to the preassigned area of the conveyor system. This process can be repeated within one subzone, and sequentially within several subzones, for filling a single order with low-demand articles which are deposited into the preassigned area.