Ice bag palletizer

Abstract

An automatic pallet stacking machine for loading bags of ice cubes onto a pallet has a first infeed conveyor with a pick and turn device for orienting the bags, and a collating conveyor adjacent a pallet holder or pallet elevator where the bags are accumulated until a row of bags is formed. Then a gantry picks up the bags and places transports the row to the pallet. The pick and turn device and the gantry employ vacuum heads that have closed cell foam side walls to accommodate the lumpy and shifting nature of the bag contents. A programmable controller ensures that the bags rows are formed in appropriate patterns so that the bags in each tier interlock with the bags in the tier beneath.

1 . Apparatus for automatically stacking bags filled with solid objects onto a pallet in layers of predetermined patterns of rows of the filled bags; comprising:
 a. a pallet holder for holding the pallet in a predetermined position;   b. a staging conveyor positioned adjacent said pallet holder;   c. an infeed conveyor receiving the filled bags from a source thereof and carrying the same to the staging conveyor;   d. an orienting mechanism aligned with said infeed conveyor for selectively lifting and turning said filled bags;   e. control means for controlling the orienting mechanism so that the filled bags are presented from the infeed conveyor to said staging conveyor such as to form rows of said bags in said predetermined patterns;   f. said staging conveyor including means for holding said bags in place until a complete row thereof has been accumulated on the staging conveyor; and   g. a bag transport mechanism for picking up each row of filled bags from said staging conveyor when the row is complete and for transferring same to a predetermined position on said pallet.   
   
   
       2 . The apparatus of  claim 1 , wherein pallet holder includes a pallet lift for holding the pallet at a predetermined elevated position adjacent said staging conveyor, and means for lowering the pallet incrementally as each layer of bags is completed. 
   
   
       3 . The apparatus of  claim 2 , wherein said pallet holder includes a torsion spring mechanism which increases the spring force on the pallet with each increment that the pallet is lowered. 
   
   
       4 . The apparatus of  claim 3 , wherein the pallet holder includes a motor drive for raising and lowering said pallet. 
   
   
       5 . The apparatus of  claim 1 , wherein said infeed conveyor includes a belt having a surface that permits sliding of said bags thereon. 
   
   
       6 . The apparatus of  claim 1 , wherein said orienting mechanism includes a rotary arm positioned over said infeed conveyor, a pair of vacuum heads positioned on said rotary arm, and means for raising and lowering the rotary arm and for selectively rotating the same for 90 degrees and for 180 degrees. 
   
   
       7 . The apparatus of  claim 1 , wherein said orienting mechanism includes means for displacing the bags to one side without rotating them. 
   
   
       8 . The apparatus of  claim 6 , wherein said vacuum heads are each formed with a rigid cap portion and an annular skirt member that depends from the cap portion and is formed of a flexible resilient material that conforms to irregularities in the surface of the bags. 
   
   
       9 . The apparatus of  claim 8 , wherein said skirt member is formed of a closed-cell foamed elastomeric material. 
   
   
       10 . The apparatus of  claim 1 , wherein said bag transport mechanism comprises a set of rails disposed above said pallet holder and spanning across said pallet and said staging conveyor; a transport assembly that is mounted to travel along said set of rails; and a set of vacuum heads disposed on said transport assembly to pick up the bags in a row of said bags and to hold same while the transport assembly travels to a position over said pallet, and to release said bags onto said pallet. 
   
   
       11 . The apparatus of  claim 10 , wherein said set of vacuum head on said bag transport mechanism includes twelve heads arranged in two rows of six heads; and the transport mechanism includes means for controlling the application of vacuum to the heads, such that vacuum can be applied selectively to either of the two rows of heads or to both of the rows of heads. 
   
   
       12 . The apparatus of  claim 1 , wherein said vacuum heads are each formed with a rigid cap portion and an annular skirt member that depends from the cap portion and is formed of a flexible resilient material that conforms to irregularities in the surface of the bags. 
   
   
       13 . The apparatus of  claim 12 , wherein said skirt member is formed of a closed-cell foamed elastomeric material.