Abstract:
The disclosure relates to a gusseted reclosable package with an internal unisex reclosure strip. The reclosure strip has upper and lower flanges, and a two or three-point connection, rather than a four-point connection, to the interior circumference of the package. This results in the package having a higher internal (product side) opening strength than the external (consumer side) opening strength, thereby allowing the package to be easily opened by the consumer while maintaining a high burst strength.

Description:
This application claims priority under 35 U.S.C. §119(e) of U.S. provisional application Ser. No. 61/152,097 filed Feb. 12, 2009, the disclosure of which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Disclosure 
     The present disclosure pertains to a gusseted reclosable package with a high burst strength and a reclosable pour spout. More particularly, the high burst strength is achieved by a two or three-point connection of the zipper, typically a unisex zipper, to the package walls. 
     2. Description of the Prior Art 
     A representative prior art package having a reclosable pour spout is disclosed in U.S. Pat. No. 6,971,794 issued on Dec. 6, 2005 and U.S. Pat. No. 7,442,156, issued on Oct. 28, 2008, both entitled “Package Having Reclosable Pour Spout and Method of Forming Same” and issued to Yeager. Such a package typically uses a unisex reclosure which is defined as a single tape that will mate or close to different sections of itself not requiring a male/female or otherwise differing zipper halves. The reclosure, comprising a single tape, is applied to the film by sealing both edges of the zipper to the film in the location where the gusset is formed. Therefore, upon opening the package or bag, a reclosable gusset is created which can act as a pour spout. The methods and apparatus typically used to apply the reclosure to the film are found in U.S. Pat. No. 5,782,733 issued on Jul. 21, 1998 and U.S. Pat. No. 6,177,172 issued on Jan. 23, 2001, both entitled “Zippered Film and Bag”, and issued to Yeager. Other prior art includes U.S. Pat. No. 7,040,810 entitled “Flexible Package with a Transverse Access Panel Device”, issued on May 9, 2006 to Steele; U.S. Pat. No. 4,929,225 entitled “Method of Making Bags and Bag Material Having Hinged Zipper Strips”, issued on May 29, 1990 to Ausnit; and U.S. Pat. No. 4,792,240 entitled “Extruded Zipper Strips for Bags” issued on Dec. 20, 1988 to Ausnit. 
     A typical zipper for this application is shown in  FIG. 1 . This zipper is a variable alignment, double-track zipper with a flange on both sides (i.e., upper and lower flanges). Because the zipper is symmetrical, the internal opening force is typically equal to the external opening force. While this is certainly acceptable for some applications, there are other applications in which it would be preferable to allow the customer to open the package with a relatively lower opening force while providing a reclosable package and zipper which can resist relatively greater internal force required for heavier loads. In other words, easy opening on the consumer side along with high burst strength on the product side may be desired. 
     Similarly, in gusseted applications, due to the mass of the zipper, it is difficult to fold the zipper fully on itself and stay closed, in the area of the gusset fold. 
     OBJECTS AND SUMMARY OF THE DISCLOSURE 
     It is therefore an object of the present disclosure to provide a reclosable package or bag, with the capability of including a gusset, and further providing a relatively lower external consumer-side opening force and a relatively higher internal product-side opening force. 
     This and other objects are obtained by providing a reclosable package or bag with a unisex reclosure strip which is attached by a two or three-point seal, thereby omitting at least part of the seal between the product-side flanges and the package walls. The reclosure strip is typically a two-flange symmetrical unisex zipper in order to reduce camber and to allow zipper introduction from either side of the manufacturing apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further objects and advantages of the invention will become apparent from the following description and from the accompanying drawings, wherein: 
         FIG. 1  is a cross-sectional view of a prior art unisex reclosure strip. This reclosure strip can be incorporated into the present disclosure. 
         FIG. 2  is a perspective view of a first embodiment of the gusseted package of the present disclosure. 
         FIG. 3  is a perspective view of a second embodiment of the gusseted package of the present disclosure 
         FIG. 4  is a diagram of a two-point seal as used in the present disclosure. 
         FIG. 5  is a diagram of a three-point seal as used in the present disclosure. 
         FIG. 6  is a diagram illustrating the effects of an internal force on the two-point seal of the present disclosure. 
         FIG. 7  is a diagram illustrating the effects of an internal force on the three-point seal of the present disclosure. 
         FIG. 8  is an illustration of a folded-out partially open gusset. 
         FIG. 9  is an illustration of a closed gusset, with a partially open portion. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that  FIG. 1  is a typical prior art reclosure strip or zipper  12  which can be used with the disclosed gusseted reclosable package or bag  10  of  FIGS. 2 and 3 . Reclosure strip  12  includes central symmetric interlocking element  14  comprising first and second engagement assemblies  16 ,  18 . First engagement assembly  16  includes a central post  20  with a bulbous head  24 , and further includes lateral arms  28 ,  32  adjacent to central post  20 , with respective distal hooked ends  36 ,  40  oriented toward central post  20 . Second engagement assembly  18  is substantially identical to first engagement assembly  16 , includes a central post  22  with a bulbous head  26 , and further includes lateral arms  30 ,  34  adjacent to central post  22 , with respective distal hooked ends  38 ,  42  oriented toward central post  22 . Upper (consumer-side) flange  46  extends upwardly from first engagement assembly  16  while lower (product-side) flange  48  extends downwardly from second engagement assembly  18 . Reclosure strip  12  can interlock with different sections of the same strip, due to the unisex and variable alignment characteristics of first and second central engagement assemblies  16 ,  18 . Upper and lower product flanges  46 ,  48  include offsets  49  to prevent or minimize the unintended sealing of the outer surface (illustrated on  FIG. 1  as the right side of the reclosure strip  12 ) of the upper and lower product flanges  46 ,  48  to an opposing surface. 
     A first embodiment of gusseted bag  10  according to the present disclosure is illustrated in  FIG. 2 . Gusseted bag  10  includes a front wall  50  and a rear wall  52  with first gusset  54  along a first side and second gusset  56  along a second side. Mouth  58  is formed along an open top end or edge of gusseted bag  10 . A single strip of reclosure strip  12 , illustrated in phantom, is sealed to a circumferential interior of front and rear walls  50 ,  52  as well as first and second gussets  54 ,  56  downwardly adjacent from mouth  58 . First and second gussets  54 ,  56  are illustrated in a closed configuration, but may also be in an open configuration to form first and second pour spouts. A two or three-point seal is used to seal reclosure strip  12  to the interior of the gusseted bag  10  as illustrated in  FIGS. 4 and 5 . The mouth of the embodiment of the gusseted bag  10  of  FIG. 2  typically extends along the entire top edge of front and rear walls  50 ,  52  with no sealing of the front and rear walls  50 ,  52  to each other in the central region  57 . In contrast, the embodiment of gusseted bag of  FIG. 3  includes sealing of the front and rear walls  50 ,  52  to each other in the central region  57 . Due to this sealing, the reclosure strip  12  can be omitted below central region  57  while remaining in the interior of first and second gussets  56 ,  58 . 
       FIG. 4  illustrates a two-point seal. The front and rear walls  50 ,  52  (or first and second gussets  54 ,  56  in the case of the embodiment of  FIG. 3 ) are illustrated as being side-by-side with reclosure strip  12  sealed thereto downwardly adjacent from the top or mouth  58 . Upper (consumer-side) flange  46  is sealed to the entire inner circumference of the package  10 , including front and rear walls  50 ,  52  as well as first and second gussets  54 ,  56 , along front and rear upper hard seal lines  60 ,  62 , respectively, illustrated as dotted lines. However, no seal line is formed between the lower (product-side) flange  48 . The presence of two hard seal lines  60 ,  62  is the basis of the term “two-point” sealing, as opposed to conventional “four-point” sealing wherein both the upper and lower flanges  46 ,  48  are sealed to both the front and rear walls  50 ,  52 . 
       FIG. 5  illustrates a three-point seal. As in  FIG. 4 , the front and rear walls  50 ,  52  (or first and second gussets  54 ,  56  in the case of the embodiment of  FIG. 3 ) are illustrated as being side-by-side with reclosure strip  12  sealed thereto downwardly adjacent from the top or mouth  58  thereof. Front and rear upper hard seal lines  60 ,  62  are formed as in  FIG. 4 . However, in the illustrated three-point sealing of  FIG. 5 , the first lower hard seal line  64  is formed only between a portion of the length of the lower flange  48  along front wall  50  and the inner circumference of the package  10  formed by the front and rear walls  50 ,  52  as well as first and second gussets  54 ,  56  (with another portion of the length of lower flange  48  being free of sealing to the inner circumference, including front and rear walls  50 ,  52  as well as first and second gussets  54 ,  56 ). A shortened bottom seal bar (not shown) is required for the first lower hard seal line  64 . Second lower hard seal line  65  extends along the entire length of the lower flange  48  along rear wall  52 . Of course, first and second lower hard seal lines  64 ,  65  may be reversed with respect to front and rear walls  50 ,  52 . The three-point seal of  FIG. 5  may be advantageous to the two-point seal of  FIG. 4  in that product contents are less likely to get caught behind a free flange. 
     The configurations of  FIGS. 4 and 5  cause the internal (product-side) opening force to increase, as an internal force will cause the opposed upper flanges  46  to align with each other as shown in  FIGS. 6 and 7  (corresponding to  FIGS. 4 and 5 , respectively), thereby causing a shear force, rather than a peeling force, on the first and second engagement assemblies  16 ,  18 . In other words, in a three-point seal, the interior (product side) forces are directed to the hinge or fold above the interlocking elements thereby placing the zipper in a horizontal mode so that the separating forces pull on the interlocking elements of the zipper in opposite directions. Additionally, with the prior art four-point seal, the reclosure strip or zipper is prone to opening because the zipper profile becomes partially distorted at the folded-in innermost point, the folded-in outer point and the folded-out outer point of the gussets. Therefore, the disclosed two and three-point seals result in a more robust connection when a gusset is partially open, such as second gusset  56  as shown in  FIGS. 8 and 9  (equally applicable to first gusset  54 ). 
     A typical comparison of the internal and external opening forces for three and four-point sealing is illustrated below: 
     
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 4-point 
                   
                   
               
               
                   
                 design 
                 3-point 
               
               
                   
                 (prior art) 
                 design 
                 Comments 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Consumer Side Opening 
                 1.3 
                      1.3 
                 Pounds to open 
               
               
                 Force 
                   
                   
                 one inch sample 
               
               
                 Internal Opening Force 
                 1.3 
                      6.8 
                 Pounds to open a 
               
               
                   
                   
                   
                 one inch sample 
               
               
                 Shake Test (fully closed) 
                 3 
                 10+ 
                 Shakes to failure 
               
               
                   
                   
                   
                 using 900 grams of 
               
               
                   
                   
                   
                 frozen french fries 
               
               
                 Shake Test (gusset 
                 2 
                 10+ 
                 Shakes to failure 
               
               
                 partially open) 
                   
                   
                 using 900 grams of 
               
               
                   
                   
                   
                 frozen french fries 
               
               
                   
               
             
          
         
       
     
     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.