Patent Publication Number: US-11383916-B2

Title: Center-pull bag dispenser without separate end-forms

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional application 62/845,536 filed May 9, 2019 and hereby incorporated in its entirety by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a plastic bag dispensing system and in particular to a plastic bag dispenser that minimizes dispenser size and waste. 
     Plastic bags can be bulky and hence are normally rolled or folded into a compact form that may be held, for example, in a cardboard container for shipping and dispensing. 
     For certain applications, for example, disposal of dog waste or infant diapers, it would be useful to have multiple plastic bags in a compact package for dispensing. In these applications, the provision of an outer cardboard or similar container can substantially increase the size and weight of the package, rendering it too bulky or heavy for convenient carrying, for example, in a purse or the like. 
     US patent publication 2016/0001961, assigned to the assignee of the present invention and hereby incorporated by reference describes a low-bulk, low weight container for dispensing compacted plastic bags. The dispenser forms the bags into a core-less roll, places circular end forms on the roll and then uses the outer periphery of the core to support a heat-shrink film providing a protective outer package. The core-less roll may provide bags that are held to each other only by electrostatic or similar attraction and the package and the roll may cooperate to queue a later bag after a previous bag is removed. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improvement on the above referenced application in which the end forms are eliminated in favor of a differentially shrinking shrink-wrap tube which shrinks inward over the ends of the roll to provide a substitute for the separate and forms without overly compressing the center of the roll. The differential shrinking can be implemented either through a tenter frame that provides different amounts of stretch to a shrink material or through the use of a heat sealing process which creates a varying diameter shrink-wrap tube. 
     Specifically, in one embodiment, compact plastic bag-dispensing package provides a core-less roll providing a web of plastic bags having a sleeve of shrink-wrap material positioned around the core-less roll and providing a central aperture through which plastic bags may be extracted through the sleeve from the web of plastic bags. The sleeve is adapted to provide, upon the application of heat, different predetermined amounts of shrinkage at different portions of the sleeve associated with different areas of contact of the core-less roll. 
     It is thus a feature of at least one embodiment of the invention to permit a shrink-wrap material to provide a packaging for core-less rolls of bags with improved stabilization of those bags by more even conformance to the roll shape. It is another feature of the invention to allow the shrink-wrap to conform to the roll shape without placing undue pressure on larger sections of the roll that would tend to form the roll. Increased resistance force to shrinkage is the normal mechanism for close conformance to an irregular shaped by shrink-wrap film but can produce unnecessary distortions in the roll especially without the use of end forms 
     The sleeve may be formed by a heat sealing of sheets of shrink-wrap material to provide a tube open along an axis before shrinking to receive the core-less roll and the different amounts of shrinkage may be controlled by changing the diameter of the sleeve formed by the heat sealing at different locations along the axis 
     It is thus a feature of at least one embodiment of the invention to pre-shape the sleeve to the roles to provide the desired conformance without undue pressure on the roll. 
     Alternatively, or in addition, the different amounts of shrinkage may be controlled by changing a stretching of the shrink-wrap material prior to heat sealing at different locations along the axis. 
     It is thus a feature of at least one embodiment of the invention to eliminate the need for complex shaping cutters and sealers by modifying the amount of shrink of the shrink-wrap material. 
     The sleeve may include an orifice formed in the sleeve to align with a central bore of the core-less roll and the orifice may be provided by a melting of material of the shrink-wrap material to form a thickened rim about the orifice. 
     It is thus a feature of at least one embodiment of the invention to eliminate the need for additional components to create a robust opening through which the bags are dispensed size to properly retain the bags in connection during the dispensing process 
     The shrink-wrap material may comprise a first and second layer, the first layer presenting an improved affinity for printing ink compared to the second layer. 
     It is thus a feature of at least one embodiment of the invention to eliminate the need for separate manufacturer steps for application of labels or the like while providing a robust container of shrink-wrap. 
     These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the package of the present invention showing dispensing of a bag from a dispenser package of the present invention having a core-less roll surrounded by a shrink-wrap film; 
         FIGS. 2 a -2 c    are simplified perspective views of the steps of producing the package of the present invention showing the formation of a sealed shrink-wrapped bag around a core-less roll, shrinking the bag to conformity with the core-less roll, and adding a slot-dispensing feature; 
         FIG. 3  is a top plan view of the core-less roll of  FIG. 1  showing a first dispensing option having a perforated opening; 
         FIG. 4  is a figure similar to that  FIG. 3  showing a second dispensing option providing a slit; 
         FIG. 5  is a figure similar to that of  FIG. 4  showing a third dispensing option providing an adhesive label cover; 
         FIG. 6  is an exploded diagram of a second packaging embodiment using rigid end forms within the shrink-wrap bag; 
         FIG. 7  is a cross-section along line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is an exploded diagram of a web formed of multiple overlapping bags showing pleating in cross-section at various locations on one bag; 
         FIG. 9  is a fragmentary top plan view of the core-less roll of  FIG. 6  showing the relative overlap of adjacent bags; 
         FIG. 10  is a top plan view of a packaging line for packaging the rolls between two sheets of shrink-wrap film heat-sealed and cut to provide differential shrinking; 
         FIG. 11  is a perspective view of a roll within the heat sealed and cut film before shrinking showing a protruding bag access neck; 
         FIG. 12  is a figure similar to that of  FIG. 11  after shrinking with a protruding bag exit port formed from the access neck; 
         FIG. 13  is a figure similar to  FIG. 12  with the bag exit port pressed into the roll and one bag partially extracted for attachment to a sealing sticker; 
         FIG. 14  is a cross-sectional view along line  14 - 14  of  FIG. 13  showing elimination of the separate end forms; 
         FIG. 15  is a top schematic view of a tenter frame for use in a second embodiment for providing differential stretching of a shrink film prior to use; 
         FIG. 16  is a schematic top view of the film (with its original outline shown in dotted lines) after being cut and heat sealed prior to shrinking; 
         FIG. 17  is a perspective simplified diagram of an aperture forming system for piercing without material removal; 
         FIGS. 18 and 19  are elevational cross-sections along lines  18 - 18  of  FIG. 7  showing the piercing operation and subsequent heating operation which forms a thickened rim of polymer material for reinforcement of the aperture; 
         FIG. 20  is a perspective view of a wall mount system for dispensing the core-less rolls of the present invention; and 
         FIG. 21  is a cross-sectional view in elevation of  FIG. 20  along line  21 - 21  showing internal spring fingers which produce improved dispensing. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     General Description 
     Referring now to  FIGS. 1 and 2   a , a bag-dispensing package  10  of the present invention may provide a generally cylindrical package form  12  having a dispensing opening  14  in the center of one base of the cylinder. Plastic bags  16  may be dispensed through the opening  14  from a core-less roll  18  generally along a central axis  41 . 
     The core-less roll  18  formed of plastic bags  16  spiral-wound about the central axis  41  and a center, open cylindrical volume  20  without the imposition of a center cardboard tube or the like. In the core-less roll  18 , the bags  16  may be attached only by electrostatic force to be readily separated when drawn through the opening  14  from out of the center of the core-less roll  18 . 
     A method of fabricating core-less rolls  18  of plastic bags  16  suitable for use with the present invention may be found in U.S. Pat. Nos. 7,066,422 and 7,273,193 both hereby incorporated by reference in their entirety. 
     Referring now to  FIGS. 2 a -2 c   , after fabrication of the core-less roll  18 , it may be placed within a tube of shrink-wrap (heat-shrink) film  22  of the type known in the art sized to closely conform to the size of the core-less roll  18 . When the core-less roll  18  is cylindrical, the shrink-wrap film  22  will conform to its outer periphery being the sidewalk of the cylinder and two opposite cylindrical bases. 
     As is generally understood in the art, shrink-wrap film  22  will be a polymer film such as a polyethylene or polypropylene stretched when it was warm, for example, on a tenter-frame to reorient, the molecules from their initial patterns in an expanded form so that when heated the shrink-wrap film  22  contracts, typically by an amount greater than 10 percent and often greater than 30 percent In one embodiment, the axis of the tube of shrink-wrap film  22  may be generally perpendicular to the axis of the open cylindrical volume at the center of the core-less roll  18 . 
     As shown in  FIG. 2 b   , open ends of the tube of shrink-wrap film  22  may be heat sealed, for example, using an L-bar sealer to provide a closed volume within the shrink-wrap film  22  holding the core-less roll  18 . 
     Referring now to  FIG. 2 c   , the application of heat  24  to the shrink-wrap film  22 , for example, using a shrink tunnel or hot-air blowers, may then cause the shrinking of the shrink-wrap film  22  to closely conform to the outlines of the core-less roll  18  and in particular to provide a substantially continuous unbroken surface of shrink-wrap film  22  at upper and lower bases of the bag-dispensing package  10 . 
     It will also be appreciated that the shrink-wrap film  22  shown in  FIG. 2 a    may be oriented so that the open ends of the tube of the shrink-wrap film  22  are vertically aligned with respect to the core-less roll  18  as depicted. The size of the tube of shrink-wrap film  22  may be adjusted so that in shrinking it provides a natural orifice aligned with the open cylindrical volume  20 . 
     Referring now also to  FIG. 4 , a knife or die may be used to make a slit cut  26  in one base through the heat shrink-wrap film  22  positioned above the center of the open cylindrical volume  20  of the core-less roll  18 . The slit cut  26  provides access to bags from the center of the core-less roll  18  through the cut  26  and also serves to retain a next overlapping bag partially, through the cut  26 , when the preceding bag is removed, for easy access of the succeeding bag. The slit cut  26  provides the opening  14 . 
     Referring now to  FIG. 3 , alternatively the shrink wrap film  22  around the opening  14  may be perforated with perforations  30  after the shrinking operation that allow removal of a circular portion of the shrink-wrap film  22  for access to the bags  16  of the core-less roll  18  from the center of the core-less roll  18  through the open volume  20 . Because the bags  16  are removed from a center of the core-less roll  18 , the outer portions of the core-less roll  18  continue to support the shrink-wrap film  22 . 
     Referring to  FIG. 3 , an adhesive sticker  32  may be placed over the opening  14  provided in the embodiment of  FIG. 3  or  FIG. 4  during shipping and then removed for use of the bag-dispensing package  10  by a consumer. A portion of one bag  16  may be partially captured by the sticker  32  during manufacturing so that it is readily accessible upon removal of the sticker  32 . Each bag  16  when fully withdrawn from the core-less roll  18  may draw the next bag upward through the opening until the bags  16  are fully consumed. 
     Referring again to  FIG. 1 , the outer surface of the bag-dispensing package  10  may be printed with images or text  34  with ink applied directly to the polymer of the shrink-wrap film  22  providing consumer information, product labeling, and the like. In some embodiments two layers of shrink-wrap may be used to provide different characteristics, for example, with a first outer layer having improved adhesion to ink compared to a second inner layer, the latter having superior mechanical strength or puncture resistance. The shrink-wrap film  22  may be transparent or opaque as desired. 
     End Form Embodiment 
     Referring now to  FIGS. 6 and 7 , in an alternative embodiment, end-forms  36  and  38 , in the form of circular disks constructed of a relatively stiff material such as cardboard or thermoplastic, may be placed against the upper and lower bases of the core-less roll  18 , the latter which approximates a circular cylinder. These end-forms  36  and  38  are then captured against the upper and lower bases of the core-less roll  18  by shrinkage of the shrink-wrap film  22  and, as so held, prevent undue compression of the upper and lower edges of the core-less roll  18  by the shrink-wrap film  22  and protect the core-less roll  18  from deformation during shipping. 
     A printed circular label  40  of paper or other similar material may optionally cover the lower end-form  38  as adhered thereto, for example, by a pressure sensitive adhesive attached to the printed circular label  40 . As so positioned, the printed circular label  40  covers the seam between the inner edge  42  of the shrunken shrink-wrap film to provide a more finished appearance and to seal the package against infiltration of contaminants. The printed circular label  40  also provides a surface on which to print additional information to be displayed on the bottom of the generally cylindrical package form  12 , for example, a UPC code and other labeling information. 
     The upper end-form  36  may provide for an inwardly extending funnel-portion  44  that may serve to capture the end of one bag  16  threaded through an orifice  46  of the funnel-portion  44 . As so captured, the end of the bags  16  is held within the funnel-portion  44  extending into the volume  20  and thus recessed within the cylindrical package form  12 . The upper end-form  36  may be advantageously injection molded or thermoformed thermoplastic as is understood in the art. 
     The diameter of the upper end-form  36  and lower end form  38  may be substantially equal to the diameter of the core-less roll  18  to protect the core-less roll  18  from deformation and possible separation of the bags  16 . Desirably, the diameter of the upper end-form  36  and lower end-form  38  may be slightly less than the core-less roll  18  so that the sidewalk of the package  10  pillow outward by ⅛ to ¼ inch for pleasing aesthetic effect and to prevent a hard edge of the end forms  36  and  38  from causing abrasion of the shrink-wrap film  22  or unpleasant contact with the consumer. The end forms  36  and  38  are relatively stiff compared to the shrink-wrap film  22  and the bags  16  to retain their shape after minor deformation. 
     Again the inner seam edge  50  of the upper end of the shrink-wrap film  22  may be covered with a circular paper label  52  having a center opening  54  exposing the funnel-portion  44  and a pressure sensitive adhesive to attach it over the upper end of the cylindrical package form  12 . As described above, a sticker  32  may have a pressure sensitive adhesive  56  on its lower surface to cover the opening  54  and the funnel-portion  44  during shipping. The funnel-portion  44  and sticker  32  thus provide an enclosed space  48  beneath the upper end of the cylindrical package form  12  in which the end of the bags  16  may be retained protected yet available for easy access by the consumer. The adhesive on the sticker  32  may retain and hold the end of the bag  16  adhered against the inner surface of the sticker  32  to prevent it from slipping out of the orifice  46 . An unadhered tab  60  on sticker  32  may be provided to allow the sticker  32  to be easily removed by pulling the tab  60  upward to remove the sticker  32  and pull with it the end of bag  16 . 
     A thin and flexible paper label  64  may be wrapped around the outer circumference of the shrink-wrap film  22  when it is shrunken to provide a surface supporting additional printed material for the consumer. The label  64  thus eliminates the need for complex printing of the shrink-wrap film  22  if desired. Alternatively a printed shrink-wrap film may be used eliminating the need for the paper label  64  or printing may be applied directly to the shrink-wrap film  22  with appropriate pre-distortion. 
     Referring now to  FIG. 8 , each bag  16  may comprise a tubular sleeve  67  of flexible plastic film extending generally along a tube axis  66  and may have multiple pleats  68  extending along the axis to convert the tube into a flattened band  71  having a width  70  (being generally the height of the package  10 ) much less than the flattened diameter of the tube and, for example, approximately ⅓ of that flattened diameter provided by three pleats extending approximately the full width  70 . A closed end  72  of each bag  16  opposite an open end  74  may be heat sealed at a seam line  75  fusing each of the pleats  68  together in overlapping configuration. Each of the bands  71  of different bags  16   a - 16   c  (only three shown for clarity) may be overlapped by an overlap distance  76 , for example, being a few inches and much less than one fourth the length of the bag along axis  66 . As shown in  FIG. 9 , each inner bag (e.g.  16   a ) will be withdrawn from the package  10  before an adjacent outer bag (e.g.  16   b ) however the outer bag  16   b  will overlap (underlap) with the inner bag  16   a  on an inner surface of the inner bag  16   a  to help preserve adhesion between the two. 
     The outside diameter of the cylindrical package form  12  may be sized to fit in a standard automotive cupholder and, for example, may be limited to no more than three inches in diameter and less than four inches in height. The final bags in the core-less roll  18  may be marked with a distinguishing color or the like to signal a need to obtain replacement stock. 
     It will be appreciated that the present cylindrical package form  12  may be used with existing dispenser racks intended for holding rectangular cardboard boxes through the use of an adapter providing an outer rectangular surface for being held firmly within the dispenser rack and an inner cylindrical bore for holding the present cylindrical package form  12 . 
     It will be appreciated that the design of the package of the present invention not only reduces packaging material but provide substantial flexibility in changing the size of the package simply by changing the number of bags  16  in a core-less roll  18 . It will be appreciated that the number of bags may be varied within a given range without necessarily changing any of the other packaging components to the extent that the diameter of the cylindrical package form  12  may change only slightly. It will be appreciated that the bags may be attached by perforations in some embodiments. 
     End Form Free Embodiment 
     Referring now to  FIG. 10 , in an alternative packaging arrangement, the individual core-less rolls  18 , prior to packaging, may be placed on an assembly line  80  providing for an axis of motion  82  of the core-less rolls  18  longitudinally. The central axis  41  of each core-less roll  18  is aligned with the axis of motion  82 . 
     Upper and lower shrink-wrap film sheets  22   a  and  22   b  having a dominant shrink axis  86  may be guided above and below each roll  18  to move with the assembly line so that the dominant shrink axis  86  is generally perpendicular to the central axes  41  of each core-less roll  18 . 
     A heat sealing tool (not shown) may press downward on the layers of the upper and lower shrink-wrap films  22   a  and  22   b  sandwiching each roll  18  therebetween. These upper and lower shrink-wrap films  22   a  and  22   b  are then sealed along a seal line  88  providing for generally wide sleeve at a center region  90  holding each core-less roll  18 . This center region  90  has substantially constant width for a height of the core-less roll  18  along the axis  41 . The center regions  90  are separated by narrow width separating regions  92  between each core-less roll  18 . The separating regions  92  may include a neck portion  94  extending from a left end of a core-less roll  18   a  to a right end of a core-less roll  18   b  at which the neck portion  94  is sealed, the neck portion  94  having substantially constant width. A tapered section  96  at about 45° joins the neck portions  94  with the wide sleeve at the center region  90  at each end of the center region  90 . 
     After heat sealing, a cutting knife (not shown) may cut along cut line  97  to cut a right portion of the neck portion  94  (without sealing) away from the sealed end of the neck portion  94  closing the volume of the succeeding roll  18 . 
     Referring now to  FIG. 11 , the core-less roll  18  will thus be in a sealed bag having an opening  98  at the neck portion  94 . As shown in  FIG. 12 , different widths of the neck portion  94  and center region  90  will caused different amounts of shrinking (albeit at a constant shrink rate per unit length) allowing the shrink-wrap film  22  to draw inward to completely cover the ends of the package  10  without the need for end forms  36  or  38  or a label  52 , for example, as shown in  FIG. 7 . 
     The opening  98  will shrink in diameter and may be pressed inward (as shown in  FIG. 13 ) to fit into the core of the core-less roll in the manner of the funnel-portion  44  of the end form. A sticker  32  or the like as discussed, for example, with respect to  FIGS. 6 and 7 , may be attached to an exposed end of one of the bags  16  as discussed above with respect to  FIGS. 6 and 7 . 
     Referring now to  FIG. 15  in an alternate embodiment (which may be combined with the embodiment of  FIGS. 10-14  or used independently) the shrink-wrap film  22  is differentially stretched on a tenter frame having tenterhooks  100  that grip the edge of the shrink-wrap film  22  while it is in the heated stage to provide a first stretching  102  in a region  104  (which will form the neck portion  94 ) and a second reduced stretching  106  in a region  108  (which will form the center region  90 ) alternating along a longitudinal length of the shrink-wrap film perpendicular to its dimension  86 . 
     Referring to  FIG. 16 , this differentially stretched material may be trimmed to a sheet and then sealed along seal lines  110  to create pouches with a rectangular periphery surrounding each roll  18  which may be cut apart along lines  112  to provide pouches having differential shrinking capability that will shrink as shown in  FIG. 12  upon the application of heat with the regions at the ends of the rolls  18  shrinking more than the center most region so as to provide coverage of the ends of the rolls without undue compression of the core-less roll such as could cause delamination of the rolls. 
     While this embodiment allows the elimination of the end forms, it will be appreciated that it also provides advantages and can be used with end forms or lighter weight or simpler end forms. Generally, these techniques allow for control of differential shrinkage In a predetermined manner that does not rely on resistance to shrinkage by the pressure on the roll. Instead differential shrinkage would occur even in the absence countervailing pressure from of a roll contained item. 
     Reinforced Aperture 
     Referring now to  FIG. 17 , a two-ply shrink-wrap film provides an outer film  22   a  having improved adhesion for printing inks compared to an inner film  22   b  which may be laminated to film  22   a  and which may have superior mechanical properties of strength and puncture resistance compared to film  22   a . Before or after forming the sheets  22  into a sleeve, the opening  14  (for example as shown in  FIG. 1 ) may be preformed in the sheets  22  by passing the sheets  22 , for example, in a continuous process along axis of motion  82 , between forming clamps  200   a  and  200   b . The forming clamps  200  will have aligned central openings  202  approximately the size of the desired opening  14  surrounded by planar surfaces that may abut when the clamps  200  are closed. As shown in  FIG. 18 , the forming clamps  200   a  and  200   b  may clamp together on opposite sides of the sheets  22  to stabilize the sheets  22 . After this, a punch  204  may pass through the central openings  202  in the forming clamps  200  to pierce the sheets  22  against a corresponding receiving die  206 . Heat may then be applied to the sheets  22  within the opening  202 , for example, by heating of the punch  204  and die  206  or, for example, from a separate heat source to melt the material of the film  22  in the opening  202 . This heating causes the sheets  22  within the opening  202  to thicken and shrink back toward the walls of the opening  202 , for example, into recesses  208  in those walls limiting the expansion of the opening  14  and defining a thickened rim. In this way, the opening  14  may be sized properly to provide resistance to the exiting bags  16 , for example, as shown in  FIG. 1  without risk of tearing or the need for additional elements. 
     Referring now to  FIG. 20 , the invention contemplates a dispensing container  220  may be used with the core-less rolls  10  and may be formed having a generally cylindrical container size so that its inner diameter closely receives the outer diameter of a core-less roll  18  therein. As so received within the container  220 , the axis  41  of the core-less roll  18  will generally be vertical and the bags  16  exiting downwardly. A lower outer edge of the core-less roll  18  may rest against an outer periphery of a lower funnel shaped portion  222  of the container  220 , this funnel shaped portion  222  leading to a downwardly displaced, reduced-size opening  14  through which bags  16  may be dispensed. The opening  14  in this case may be larger than necessary to promote the proper dispensing of the bags  16  but may include internal spring fingers  228  biased together about opposite sides of an individual bag  16  being dispensed to provide a well-defined drag on that bag  16  improving the dispensing of the bags  16 , for example, to ensure connection of subsequent bags to a point of exit from the opening  14 . 
     The container  220  may be mounted with the funnel portion  222  downward, for example, as supported by a wall bracket  224  attached to the outer circumference of the container  220 . A loosely fitting lid  230  may be used to cover an upper opening of the container  220  through which the core-less roll  18  may be inserted or replaced. 
     Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
     When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications, are hereby incorporated herein by reference in their entireties.