High-Capacity, High-Speed Bag Loading and Sealing System

Abstract

A bag loading and sealing system and method in which a continuous web of bags is continuously moved along a line. The web of bags is slit open to expose the interior of the bags and the bags of the web are separated from each other by a rod engaging perforated lines of separation between the bags. The open tops of the bags define a pair of flaps, each of which is gripped by a gripping chain, the paths of which diverge to form a mouth at the top of the bag. Material is deposited into the bag through the mouth and the gripper chains then converge to close the bag. The bags are transferred to gripper belts, with the top edge of the bag being slit off between the belts and the bags being transported through a hot air sealer where the remaining portions of the top of the bags are melted and fused together. A spool-type take-up winder is provided to retrieve the portion of the bags trimmed from the tops thereof.

What is claimed is: 
     
         1 . A bag loading and sealing system, comprising:
 a continuous web of bags sharing a common tubular top strip;   a first station having a slitting blade for slitting said tubular top strip into a pair of opposed linear strips, and a gripper associated with each of said pair of opposed linear strips for gripping, opening and transporting said bags by each associated linear strip;   a transport and filling section in which an open mouth of each said bag is exposed for receiving material; and   a sealing section, sealing said linear strips together and thereby sealing each of said bags with material therein.   
     
     
         2 . The bag loading and sealing system according to  claim 1 , wherein said bags of said continuous web of bags are separable from each other by lateral lines of perforation. 
     
     
         3 . The bag loading and sealing system according to  claim 2 , wherein said first station further comprises a perforation separator for sequentially engaging said lateral lines of perforation and separating said bags from each other. 
     
     
         4 . The bag loading and sealing system according to  claim 3 , wherein said perforation separator comprises an elongated member traversing said web at each said lateral line of perforation. 
     
     
         5 . The bag loading and sealing system according to  claim 3  further comprising an optical sensor monitoring movement of said bags and signaling when a lateral line of perforation is aligned with said perforation separator. 
     
     
         6 . The bag loading and sealing system according to  claim 3 , wherein said grippers move in unison along paths that diverge, said diverging movement opening said bags and defining said mouth. 
     
     
         7 . The bag loading and sealing system according to  claim 6 , wherein said grippers comprise gripper chains of interconnected gripping links caused to open and close by associated cam sprockets. 
     
     
         8 . The bag loading and sealing system according to  claim 7 , wherein an extent of divergence of said paths of said gripper chains is adjustable. 
     
     
         9 . The bag loading and sealing system according to  claim 8 , wherein said transport and filling section comprises a pair of work shelves having an opening therebetween, each of said gripper chains following a track beneath an associated one of said work shelves, a separation between said work shelves being adjustable by a threaded rod interconnecting said work shelves. 
     
     
         10 . The bag loading and sealing system according to  claim 9 , wherein a pair of cam sprockets receiving said gripper chains are mounted to a slidable plate biased to maintain a constant tension on said gripper chains independent of said adjustable separation of said work shelves. 
     
     
         11 . The bag loading and sealing system according to  claim 10 , wherein said slidable plate is biased by an air cylinder. 
     
     
         12 . The bag loading and sealing system according to  claim 6 , wherein said lateral lines of perforation terminate at slits at an edge of said common tubular top strip, wherein said slits allow said mouth to form rectangularly. 
     
     
         13 . The bag loading and sealing system according to  claim 8 , further comprising a first pair of belt grippers receiving said web of bags from said gripper chains and transporting said web of bags by an upper portion of said pair of opposed linear strips. 
     
     
         14 . The bag loading and sealing system according to  claim 13 , further comprising a second pair of gripper belts engaging a lower portion of said pair of opposed linear strips. 
     
     
         15 . The bag loading and sealing system according to  claim 14 , further comprising a trimming blade interposed between said first and second pairs of gripper belts, said trimming blade severing off an upper portion of said opposed linear strips. 
     
     
         16 . The bag loading and sealing system according to  claim 15 , wherein said second pair of gripper belts transports said web of bags through a hot air sealer comprising said sealing section. 
     
     
         17 . The bag loading and sealing system according to  claim 16 , wherein said hot air sealer comprises spaced manifolds receiving said second pair of gripper belts therebetween, said manifolds blowing hot air onto a top remaining portion of said opposed linear strips, melting and fusing them together. 
     
     
         18 . The bag loading and sealing system according to  claim 17 , further comprising crimp rollers downstream of said manifolds for crimping said melted and fused portions of said linear strips. 
     
     
         19 . The bag loading and sealing system according to  claim 15 , further comprising a trim winder receiving said upper portion of said opposed linear strips onto a spool. 
     
     
         20 . The bag loading and sealing system according to  claim 19 , wherein said trim winder comprises a carriage reciprocatingly driving back and forth across a rod, said carriage receiving said trimmed upper portion of said opposed linear strips and transferring them onto said spool. 
     
     
         21 . A method for opening, filling, and sealing the bags of a tubular web of interconnected bags, comprising:
 slitting open a top edge of said web of bags to expose an interior of each bag;   gripping opposed flaps of said slit top edge by a moving gripper chain;   separating said bags of said web from each other;   opening a mouth of said bags by diverging travel of said moving gripper chain;   filling said bags with material;   transferring said filled bags to gripper belts;   slitting off top portions of said opposed flaps; and   heat-sealing together remaining portions of said flaps.