Abstract:
An air valve for a poly bag that permits the escape of air from the bag as it is filled by a filling tube. The air valve consists of a plurality of slitted openings in one top corner of the bag and a valve flap mounted in the poly bag near the slitted openings that closes and seals the openings as filling material engages and moves the flap.

Description:
BACKGROUND OF THE INVENTION 
   Side gusseted paper bags have been commercially made for many years with openings that permit bag charging or filling. But these bags are quite costly, not only because of the additional materials needed about the bag filling opening, but also because of the labor and time to close and seal the bag. 
   One of the problems with fillable bags is the entrapment of air during the filling process which promotes poor filling and other problems. 
   The following patents were found in a preliminary patentability search: 
   
     
       
             
           
             
             
             
             
           
         
             
                 
             
             
               U.S. patents 
             
           
        
         
             
                 
               Inventor 
               U.S. Pat. No. 
               Issue Date 
             
             
                 
                 
             
             
                 
               Harvey 
               3,276,670 
               Jul. 27, 1964 
             
             
                 
               Piazze 
               3,618,478 
               Nov. 9, 1971 
             
             
                 
               Benoit 
               4,571,235 
               Feb. 18, 1986 
             
             
                 
               Benoit 
               4,655,737 
               Apr. 7, 1987 
             
             
                 
               Roen, et al. 
               4,717,262 
               Jan. 5, 1988 
             
             
                 
               Humphrey 
               4,764,030 
               Aug. 16, 1988 
             
             
                 
               Benoit 
               4,816,104 
               Mar. 28, 1989 
             
             
                 
               Olesen 
               4,881,825 
               Nov. 21, 1989 
             
             
                 
               Beer 
               4,913,561 
               Apr. 3, 1990 
             
             
                 
               Gelbard 
               4,943,167 
               Jul. 24, 1990 
             
             
                 
               Mundus 
               4,959,114 
               Sep. 25, 1990 
             
             
                 
               Wood 
               5,165,799 
               Nov. 24, 1992 
             
             
                 
               Gebhardt 
               5,676,467 
               Oct. 14, 1997 
             
             
                 
               Schoeler 
               5,862,652 
               Jan. 26, 1999 
             
             
                 
               Daniels, et al. 
               Re.36,876 
               Sep. 19, 2000 
             
             
                 
               Beer 
               6,213,645 
               Apr. 10, 2001 
             
             
                 
               Angless 
               6,254,520 
               Jul. 3, 2001 
             
             
                 
                 
             
           
        
       
     
   
   UNITED STATES PATENT APPLICATION PUBLICATION 
   
       
       Totani Pub. No.: US 2001/0002938
       Pub. Date: 7-7-01   
     
     
  
   FOREIGN PATENTS 
   
       
       Interpoly Limited, UK Patent Application
       GB 2 226 541A   Publication Date: 4-7-90   
     
     
  
   The Harvey, U.S. Pat. No. 3,276,670, shows a tapered side gusseted bag but has no filling valve. The Piazze, U.S. Pat. No. 3,618,478, shows a gusseted bottom bag with diagonal heat seals but has no filling valve either. 
   The Benoit, U.S. Pat. Nos. 4,571,235 and 4,816,104, show a T-shirt bag with diagonal heat seals at the bottom. Again, it has no filling valve. The Benoit, U.S. Pat. No. 4,655,737, is duplicative with respect to the Benoit &#39;235 patent. 
   The Roen, et al., U.S. Pat. No. 4,717,262, shows a gusseted bottom bag with diagonal heat seals and a sine wave handle. The Humphrey, U.S. Pat. No. 4,764,030, shows serrated bags on a roll but no discharge or filling valve. 
   The Olesen, U.S. Pat. No. 4,881,825, discusses both a filling valve and a discharge valve and a “block” style bottom and top, formed by folding and overlapping the ends of an open tube onto itself much like gift wrapping a box but tucking the sides inwardly and then folding the paper onto itself. See  FIG. 10 , for example. The discharge valve is for the purpose of pouring product out of the bag and no details are shown of the charging features in Olesen&#39;s bag. 
   The Beer, U.S. Pat. No. 4,913,561, shows what appears to be a valve on the upper left corner of the bag but rather than that, it is a heat seal which is intended to allow the bag to square once it is filled with product. 
   The Gelbard, U.S. Pat. No. 4,943,167, shows a side gusseted T-shirt bag made three across at one time and involves the continuous slitting and heat sealing of one tube longitudinally into three longitudinal tubes, post gusseting and heat sealing to create a top and bottom of the bag. 
   The Mundus, U.S. Pat. No. 4,959,114, shows a method which includes feeding flat sheet roll stock, folding it over into two, post gusseting it and sealing it into gusseted tubing with a longitudinal heat seal and then trimming off the excess. 
   The Wood, U.S. Pat. No. 5,165,799; the Gebhardt, U.S. Pat. No. 5,676,467; the Schoeler, U.S. Pat. No. 5,862,652; the Daniels, et al., Re.36,876; the Beer, U.S. Pat. No. 6,213,645; the Angless, U.S. Pat. No. 6,254,520; the Totani, Pub. U.S. 2001/0002938, published Jul. 7, 2001; and the Interpoly Limited U.K. Patent Application GB 2 226 541A, published Apr. 7, 1990, all show gusseted bags, gusseted T-shirt bags, laminated film structure gusseted bags, trifolded bags, post-bag making, and a separate bottom panel system sealed into a tube on four sides that shows an accordion type bag. None of these latter patents have filling systems. 
   It is a primary object of the present invention to ameliorate the problems noted above in prior art chargeable bags. 
   SUMMARY OF THE PRESENT INVENTION 
   In accordance with the present invention, an air valve for a polybag is provided that permits the escape of air from the bag as it is filled by a filling tube. The air valve consists of a plurality of slitted openings in one top corner of the bag and a valve flap mounted in the polybag near the slitted openings that closes and seals the openings as filling material engages and moves the flap. 
   The valve flap is generally rectangular and constructed of a material similar to the polybag itself. It may be heat sealed behind one of the panels of the polybag adjacent the corner of the bag where the filling tube is inserted. This location is selected because it is the area of bag that is last to fill. The bag fills diagonally toward that corner because of the filling tube orientation. 
   The openings in the polybag itself are crossed slits to achieve better sealing by the flap valve, while the holes in the flap valve are circular to promote air flow. 
   In some cases the holes in the flap valve may be eliminated because, depending upon bag construction, air may flow around the flap valve out the polybag slitted openings. The holes in the flap valve prevent the premature closing of the polybag air openings. 
   Other objects and advantages will appear more clearly from the following detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a top/square bottom bag with the air valve shown partly in dotted lines; 
       FIG. 2  is a fragmentary perspective view similar to  FIG. 1  illustrating the manner of folding; 
       FIG. 3  is a vertical section through the upper part of the bag; 
       FIG. 4  is an exploded perspective view similar to  FIG. 2  showing the manner of mounting the flap valve with an exemplary filling tube; 
       FIG. 5  is a fragmentary view of the square bottom of the bag shown in  FIGS. 1 to 4 ; 
       FIG. 6  is a fragmentary view of the bottom of the bag shown in  FIG. 5  after heat sealing; 
       FIG. 7  is a vertical longitundinal section through the bag during filling; 
       FIG. 8  is similar to  FIG. 7  about 60% filled; 
       FIG. 9  is a vertical section similar to  FIGS. 7 and 8  with the filling tube flap valve in its sealed position; 
       FIG. 10  is a fragmentary perspective of the present air valve incorporated into a side gusseted poly bag; 
       FIG. 11  is a perspective view of the side gusseted bag illustrated in  FIG. 10  with the top heat sealed, and; 
       FIG. 12  is a fragmented longitudinal section showing the attached position of the flap valve illustrated in  FIGS. 10 and 11 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present air valve can be incorporated in a variety of different types of poly bags including the square top and square bottom poly bag illustrated in  FIGS. 1 to 9 , the side gusseted poly bag illustrated in  FIGS. 10 ,  11 , and  12  and open bottom bags(not illustrated). 
   Referring to the drawings and particularly  FIGS. 1 and 2 , the square bottom bag  10  is illustrated including a front panel  11 , side panels  12  and  13 , rear panel  15  (see  FIG. 3 ), a top  16  formed by inwardly folding upper side panel portions  18  and  19  over which are folded front wall portion  21  and rear wall portion  22 . The heat sealing lines are designated at  25 ,  26 , and  27 . A tubular panel  29  is fixed to side panel portions  18  by heat sealing at  30  (see also  FIG. 3 ) and forms part of the filling tube chute. The upper bight portion  32  of sheet  21 , is heat sealed by  25 ,  26 ,  27  to the front wall panel  21  and rear wall panel  22 . 
   The heat seal at  25  and  26  does not attach the side wall portion  21  to the top panels  21  and  22  so that feeding tube  34  may be inserted between panel portions  21  and  22  and side panel portions  18  to fill the bag. At the right top portion of the bag, however, heat sealing portion  27  does seal top panels  21  and  22  to the side panel portion  19  so that the right top portion of the bag is always sealed. 
   In  FIGS. 5 and 6 , the square bottom  40  of the bag is illustrated with appropriate heat sealing lines  41 . 
   As seen in  FIGS. 1 to 4 , an air escape valve  40  is illustrated including four cross-slitted openings  41  in side panel portion  18  and a flap valve  43  having a plurality of round holes  45  therein that are offset inwardly relative to the bag with respect to the cross slit openings  41  to achieve the desired sealing of the cross slit openings  41  as the flap valve moves upwardly as seen in  FIG. 3 , closing off the openings  41 . 
   The flap valve  43  is generally rectangular and is heat sealed at  46  to the underside of the side panel portions  18 , as seen in exploded fashion in  FIG. 4 . 
   As seen in  FIGS. 7 ,  8 , and  9 , as material is discharged into the bag from the feeding tube  34 , material in the bag fills the bag diagonally as seen at  48  in  FIGS. 6 and 49  in  FIG. 7  relative to the corner of the bag at which the air valve  40  is located. This permits the valve  40  to remain open to permit air to escape until the bag is almost completely filled and is an important aspect of the present invention. 
   As seen in  FIG. 9 , when the bag becomes almost completely filled, the valve  40  seals the opening  41  and as the feeding tube  34  is withdrawn from the chute  21 , material collapses the heating chute against the top wall portions  21  and  22 . 
   As mentioned above, as the bag fills, air exits the bag through holes  43  and slitted opening  41 . Air flowing through the holes  43  maintains the flap  45  in an opened position and prevents inadvertent closure. In some cases this is not a problem, and in those cases it may be possible to eliminate the holes  43 . It should be understood that the material itself and not air impinging on the lower surface of the flap  45  closes the valve to the position illustrated in  FIG. 9 . 
   A gusseted poly bag  110  is illustrated in  FIGS. 10 ,  11 , and  12 , incorporating the present air valve  140  that operates in substantially the same manner as the valve  40  in  FIGS. 1 to 9  embodiment. In the gusseted poly bag  140 , the inward extension  121  of the upper portion of side gusset  112  defines the chute  121   a  shown in  FIG. 11 , and a separate panel  21  is unnecessary as shown in  FIGS. 1 to 9 . Flap valve  143  is heat sealed at  146  to the outward part of folded in gusset portion  121 . Cross slits  141  are formed in the upper reaches of the side gusset  112  slightly beneath the fold line  165 . As in the  FIGS. 1 to 9  embodiments, the holes  145  in the flap valve  143  are offset from the cross slitted openings  141 . Valve  140  operates in the same fashion as in the  FIGS. 1 to 9  embodiments but the location of the valve is slightly different.