Patent ID: 6022017
Filing Date: 2000-02-08
Classification: B65H

Abstract:
In a stacker for paperboard sheets wherein sheets are individually fed at a fixed line speed onto a first shingling conveyor operating below line speed to form a shingle of sheets, and thereafter the shingle is conveyed over a plurality of downstream conveyors at a discharge speed to a stacking device where the shingle is formed into a vertical stack of sheets, a method for preventing edge butt at order change between the lead edge of the first sheet for a new order and the tail edge of the last sheet for an old order, said method comprising the steps of:(1) utilizing the gap between the lead edge and the tail edge at an order change position when said tail edge is on the upstream end of the shingling conveyor, the difference between the line speed and the shingling conveyor speed, and the length of the new order sheet to determine if edge butt will occur;(2) preventing the occurrence of edge butt by implementing a routine to adjust the speeds of the shingling conveyor and downstream conveyors, said routine selected from one of:(a) shingling the first sheet of the new order on the old order; and,(b) with the first and last sheets in the order change position, accelerating the shingling conveyor and downstream conveyors together to a speed approaching line speed sufficient to prevent the gap from closing before the tail edge of said new order first sheet reaches the upstream end of the shingling conveyor; and,(3) thereafter returning the conveyors to discharge speed.