Patent Publication Number: US-7909750-B2

Title: Method and apparatus for feeding large packages or bags into a reclosable zipper profile attaching device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method and apparatus for manufacturing large reclosable packages or bags, wherein the reclosable packages are placed onto a conveyor belt with a constant center-to-center distance for the application of reclosable zippers thereon. 
     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. In particular, 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. 
     However, further improvements are always sought, particularly with respect to the loading of the large reclosable packages or bags onto a conveyor belt so as to achieve a constant center-to-center spacing in preparation for the subsequent placing of reclosable zipper profiles onto the packages or bags. In the prior art, this has been done using a variable speed gearbox and a dynamic conveyor nip. However, it has been found that the use of variable speed gearboxes in this regard has led to deficiencies in accuracy. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a method and apparatus for the loading of packages or bags onto a conveyor belt in order to accurately achieve a constant center-to-center spacing in order to subsequently place the reclosable zipper profiles onto the packages or bags in a way that maintains or improves the manufacturing speeds and manufacturing costs. 
     This and other objects are obtained by providing a method and apparatus wherein individual or loose packages are placed on a servo-driven, lugged chain conveyor belt. The lugs are formed on the chain at the nominal desired center-to-center distance to be achieved with the packages or bags. The lug chain feeds the individual or loose bags or packages into a constant velocity conveyor belt, which captures the package or bag on both the top and bottom. An encoder is attached to the constant velocity conveyor belt system. This encoder is used to slave the servo-driven lug chain with an adjustable, programmable ratio. By slaving the servo drive to the conveyor, a consistent center-to-center distance can be achieved, and with programming adjustments, the center-to-center distance can be adjusted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawings and claims, wherein: 
         FIG. 1  is a side schematic view of the feeding apparatus of the present invention. 
         FIG. 2  is a top plan view of the chains with the spaced lugs, used with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings in detail, wherein like numerals refer to like elements, one sees that  FIG. 1  is a side schematic view of the feeding apparatus  10  of the present invention. 
     Loose packages or bags  100  are illustrated as being supplied from stack  102  by a “pick and place” apparatus  103 , but stack  102  and apparatus  103  could likewise be replaced with another conveyor belt or other equivalent source. The packages or bags  100  initially provided in stack  102  typically include the walls of the package or bag  100 , without the reclosable zipper. The bottom of the package or bag  100  may be open or closed, depending upon the filling configuration. Particularly in view of the horizontal orientation of packages or bags  100  in stack  102 , it is envisioned that typically these packages or bags  100  would be empty of the contents (such as a food product, charcoal, animal feed, fertilizer, seeds, etc.) and that subsequent filling steps (not shown) would be used. However, some embodiments of the present invention may include previously filled packages or bags  100 . 
     Packages or bags  100  are periodically dispensed from the stack  102  so as to be placed on moving servo-driven chain conveyor  12 . As shown in  FIG. 2 , moving servo-driven chain conveyor  12  includes first and second sprocket sets  13 A,  13 B and  15 A,  15 B (or similar driving apparatus) which drive first and second chains  14 ,  16 . First and second chains  14 ,  16  includes lugs  18  which are periodically spaced at a distance equal to the nominally desired center-to-center spacing of the packages or bags  100  to be fed to the zipper profile attaching device  1000 . As likewise shown in  FIG. 2 , the sides of packages or bags  100  are oriented in the transverse direction while the tops and bottoms of packages or bags  100  are oriented in the machine direction, as typically required by the zipper profile attaching device  1000 . 
     The packages or bags  100  are conveyed by moving servo-driven chain conveyor  12  and periodically transported onto lower secondary constant velocity conveyor  20 , including first and second rolls  19 ,  21 , which likewise transports packages or bags  100 . As packages or bags  100  are transferred from servo-driven chain conveyor  12  to lower secondary constant velocity conveyor  20 , lugs  18  drop out of the path of packages or bags  100 . The point at which lugs  18  drop out of contact with packages or bags  100  is adjustable. Packages or bags  100  are then additionally engaged under upper secondary constant velocity conveyor  24 , including first and second rolls  23 ,  25 , thereby capturing the sequence of packages or bags  100  between lower and upper secondary constant velocity conveyors  20 ,  24 , which may be an integral part of attaching device  1000  (see phantom lines in  FIG. 1  extending attaching device  1000  over the upper and lower secondary constant velocity conveyors  20 ,  24 ) or, in other applications, be separate therefrom. 
     As shown in  FIG. 1 , the lower secondary constant velocity conveyor  20  includes encoder  30 . Encoder  30  is used to slave the servo  40  of the moving servo-driven chain conveyor  12  with an adjustable programmable ratio as implemented by CPU  50 . By slaving the servo  40  of servo-driven chain conveyor  12  to the encoder  30  of lower secondary constant velocity conveyor  20 , a consistent nominal center-to-center distance (equal to the spacing between successive lugs  18  on first and second chains  14 ,  16 ) between successive packages or bags  100  can be achieved. Moreover, with programming adjustments via the CPU  50 , this center-to-center distance can be varied to a different distance, other than the nominal center-to-center distance. 
     This feeding apparatus  10  thereby provides a sequence of regularly spaced horizontally oriented packages or bags  100  to zipper profile attaching device  1000  for subsequent attachment of the zipper profiles and the finishing of the package or bag. 
     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.