Patent Publication Number: US-2010122892-A1

Title: Registration method for multiwall paper and woven packages

Description:
This application claims priority under 35 U.S.C. §119(e) of provisional application Ser. No. 61/115,791 filed Nov. 18, 2008, the contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and method which uses a separate registration staging drive for registering packages or bags, particularly large multiwall and woven packages or bags, into a machine, such as a main conveyor, that processes such packages or bags. 
     2. Description of the Prior Art 
     The prior art of reclosable packages or bags and the manufacture thereof is well-developed and satisfactory for its intended purposes. Some devices in current use employ a lug chain to feed packages or bags in the main conveyor or nip roller with no feedback for registration. Registration is only as accurate as the speed control of the lug and the main conveyor with no consideration to product defects such as wrinkles. Because the lug chain pushes the bag from the trailing edge into a belt conveyor at the leading edge, wrinkles in the package or bag causes registration errors in the belt conveyor. 
     Large reclosable packages and the methods of manufacture thereof are disclosed in commonly assigned U.S. patent application Ser. No. 11/728,477 entitled “High Burst Zipper Assembly for Large Reclosable Packages”; U.S. patent application Ser. No. 11/728,405 entitled “Method of Producing High Burst Zipper Assemblies for Large Reclosable Packages” and application Ser. No. 11/728,413 entitled “Hot-melt Adhesive Systems for Zipper Assemblies on Large Bag Constructions of Various Substrates”, all filed on Mar. 26, 2007. Similarly, methods for feeding large packages are described in commonly assigned U.S. patent application Ser. No. 11/891,697 entitled “Method for Feeding Large Packages or Bags Into a Reclosable Zipper Profile Attaching Device”, filed on Aug. 13, 2008. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     It is therefore an object of the present invention to improve the registration of packages or bags, particularly large multiwall or woven packages or bags, into a machine that processes the packages or bags. 
     This and other objects are attained by a method and apparatus which registers large multiwall or woven package or bags into a machine by the use of a separate registration staging device. The packages or bags are placed on a table with chains that have an attachment to drive them into the staging conveyor. After the package or bag is captured by the staging conveyor, its leading edge is sensed by a photo-electric eye. The position of the leading edge is then fed back to a programmable logic controller or similar microprocessor whereby calculations are performed to control the servo whereby the speed of the registration staging device is increased or decreased to present the package or bag into the main machine conveyor at the correct time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawing, wherein: 
         FIG. 1  is a schematic of an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that  FIG. 1  is a schematic of an embodiment of the registration apparatus  10  of the present invention. 
     Initial conveyor  12  includes two opposed rollers  14 ,  16  with lug chains  18  traveling thereon (typically one lug chain proximate to each lateral edge of initial conveyor  12 ). In the illustration and orientation of  FIG. 1 , lug chains  18 , as well as rollers  14 ,  16 , are traveling in a clockwise orientation, typically at a constant speed. Lug chain  18  includes evenly spaced lugs  20  which engage the trailing edge of successive packages or bags  100 . Packages or bags  100  are typically large multiwall paper or woven bags. Those skilled in the art will recognize a broad range of possible contents for the packages  100 , including, but not limited to, charcoal, pet food, livestock or other animal food, cat litter, fertilizer, seeds, plant bulbs, rock salt, and foodstuffs. 
     Initial conveyor  12  successively passes packages or bags  100  to staging conveyor  30 . Staging conveyor  30  includes upper and lower belts  32 ,  34 . Upper belt  32  traverses the path defined by first and second upper rollers  36 ,  38  while lower belt  34  traverses the path defined by first and second lower rollers  40 ,  42 . Nip  44  is formed between upper and lower belts  32 ,  34  as upper and lower belts  32 ,  34  pass between first upper roller  36  and first lower roller  40 . The lower path of upper belt  32  and the upper path of lower belt  34  impinge against each other so as to engage the packages or bags  100  securely therewithin and to temporarily remove wrinkles from the packages or bags  100  during processing. Second upper roller  38  is illustrated as driven by servo  50 , but those skilled in the art will realize, after review of this disclosure, that other rollers could be driven. The movement of second upper roller  38  likewise induces the movement of rollers  36 ,  40 ,  42  as well as that of upper and lower belts  32 ,  34  due to the contact between upper and lower belts  32 ,  34 . Servo  50  is controlled by programmable logic controller (or similar microcomputer or other computing device)  52 . Programmable logic controller  52  receives information fed back from photo-electric eye  54  which senses the leading edge of the package or bag after the package or bag  100  is captured within staging conveyor  30  and is passing through the staging conveyor  30 . This information is used by the programmable logic controller  52  to adjust (i.e., increase or decrease) the speed of the belts and rollers of the staging conveyor  30  via servo  50  whereby the packages or bags  100  can be introduced into the main conveyor  60  at the correct or desired time, as required by the specifics of the operation of main conveyor  60 . The photo-electric eye  54  is illustrated in  FIG. 1  as being within the loop formed by upper belt  32 , but those skilled in the art will recognize, after review of the disclosure, will recognize that other positions may be desirable to accurately sense the leading edge of the package or bag  100 . 
     Main conveyor (or subsequent conveyor or other similar device)  60  typically includes upper and lower belts  62 ,  64 . Upper belt  62  traverses the path defined by first and second upper rollers  66 ,  68  while lower belt  64  traverses the path defined by first and second lower rollers  70 ,  72 . Nip  74  is formed between upper and lower belts  62 ,  64  as upper and lower belts  62 ,  64  pass between first upper roller  66  and first lower roller  70 . The lower path of upper belt  62  and the upper path of lower belt  64  impinge against each other so as to engage the packages or bags  100  securely therewithin. The speed of the upper and lower belts  62 ,  64  and rollers  66 ,  68 ,  70 ,  72  is typically constant, and may be either the same or different as the speed of the initial conveyor  12   
     By way of the control of the speed of staging conveyor  30  as described above, packages or bags  100  are introduced to nip  74  at the desired time, typically to achieve a controlled position for improved registration. This desired time may vary depending upon the specific application and function of main conveyor  60 , and would be known by those skilled in the art, after review of the present disclosure. 
     Further embodiments of this invention would include the use of two staging conveyor drives and sensors (one on each lateral edge of the package or bag  100 ) to square the package or bag  100 . Similarly, a staging roller could be used instead of a staging conveyor. 
     Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.