Abstract:
This invention discloses a resealable bag. The resealable bag includes a first and second panel joined together to define an enclosed region, a closure mechanism having first and second closure profiles, a slider for selectively opening and closing the closure mechanism, and a spreader for separating the first and second closure profiles.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. application Ser. No. 10/165,026, filed on Jun. 7, 2002, the disclosure of which is fully incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to a method of producing closure mechanisms for polymer packages, for example, plastic bags. In particular, the present invention relates to applying a slider device to the closure mechanism of a resealable bag.  
       BACKGROUND OF THE INVENTION  
       [0003]     Many packaging applications use resealable containers to store various types of articles and materials. These packages may be used to store and ship food products, non-food consumer goods, medical supplies, waste materials, and many other articles. Resealable packages are convenient in that they can be closed and resealed after the initial opening to preserve the enclosed contents. The need to locate a storage container for the unused portion of the products in the package is thus avoided. As such, providing products in resealable packages appreciably enhances the marketability of those products.  
         [0004]     Resealable packages typically utilize a closure mechanism that is positioned along the mouth of the package. The closure mechanism often comprises profile elements or closure profiles that engage one another when pressed together and to disengage when pulled apart. Some packages also include a slider device that can be moved back and forth across the mouth of the package to open and close the closure mechanism. In many cases, the slider device includes some sort of plow or spreader device that serves to drive apart the closure profiles as it is moved along the closure mechanism, thereby opening the package. In the manufacturing process, the slider device is usually attached to the closure mechanism while the closure profiles are closed. The closure profiles are provided with a notch at one end. The slider device is placed on the closure profile at the notch, giving the spreader a starting point from which to penetrate the engaged closure profiles.  
         [0005]     One reason for attaching the slider to the closure mechanism while the closure profiles are engaged is that it is often difficult to align an open set of closure profiles in the small and curved spaces between the walls of the slider device and the outside of the spreader. As a result of having to attach the slider to a closed package, it is necessary to move the slider device along the closure mechanism to open the package so the package may be filled with product. It is therefore desirable to provide a method of attaching a slider device to an open closure mechanism to eliminate the additional manufacturing step.  
       SUMMARY OF THE INVENTION  
       [0006]     In an embodiment of the present invention, a method of applying a slider to a closure mechanism for a resealable package is provided. The method comprises providing a closure mechanism having first and second closure profiles, the first closure profile comprising a first base strip and a first upper flange. The first base strip has a first interlocking member extending therefrom. The second closure profile comprises a second base strip and a second upper flange, the second base strip having a second interlocking member extending therefrom. The first and second interlocking members are constructed and arranged to selectively interlock. The method further comprises providing a slider for selectively opening and closing the closure mechanism, the slider comprising a top wall and a pair of side walls. The top wall and side walls define a cavity sized to receive the first and second upper flanges. The slider also comprises a spreader for separating the first and second closure profiles, the spreader depending from the top wall of the slider. The spreader has a channel through which the first and second upper flanges may pass as the slider is moved along the closure mechanism. The method further comprises attaching the slider to the closure mechanism while the first and second closure profiles are at least partially disengaged, wherein the first and second upper flanges are both positioned in the channel through the spreader.  
         [0007]     In another embodiment of the present invention, an alternate method of applying a slider to a closure mechanism for a resealable package is provided. The method comprises attaching the slider to the closure mechanism while the first and second closure profiles are at least partially disengaged, wherein the first and second upper flanges are both disposed in a first position that is different than a second position where the first and second upper flanges are positioned in subsequent closings in normal operation.  
         [0008]     In another embodiment of the invention, a resealable bag is provided. The resealable bag comprises first and second panel sections joined together to define an enclosed region, first and second opposite side edges, a bottom and a mouth that provides access to the enclosed region. The bag further comprises a closure mechanism having first and second closure profiles. The first closure profile comprises a first base strip and a first upper flange, the first base strip having a first interlocking member extending therefrom. The second closure profile comprises a second base strip and a second upper flange, the second base strip having a second interlocking member extending therefrom. The first and second interlocking members are constructed and arranged to selectively interlock. The bag further comprises a slider for selectively opening and closing the closure mechanism, the slider comprising a top wall and a pair of side walls, the top wall and side walls defining a cavity sized to receive the first and second upper flanges. The slider further comprises a spreader for separating the first and second closure profiles, the spreader depending from the top wall. The spreader has a channel therethrough, and the first and second upper flanges are positioned within the channel.  
         [0009]     In another embodiment of the invention, a closure mechanism for a resealable bag is provided. The closure mechanism has first and second closure profiles. The first closure profile comprises a first base strip and a first upper flange, the first base strip having a first interlocking member extending therefrom. The second closure profile comprises a second base strip and a second upper flange, the second base strip having a second interlocking member extending therefrom. The first and second interlocking members are constructed and arranged to selectively interlock. The bag further comprises a slider for selectively opening and closing the closure mechanism, the slider comprising a top wall and a pair of side walls, the top wall and side walls defining a cavity sized to receive the first and second upper flanges. The slider further comprises a spreader for separating the first and second closure profiles, the spreader depending from the top wall. The spreader has a channel therethrough, and the first and second upper flanges are positioned within the channel. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The various features and benefits of the present invention are apparent in light of the following detailed description and the accompanying drawings, in which:  
         [0011]      FIG. 1   a  is a perspective view of a flexible, resealable package in accordance with an embodiment of the present invention.  
         [0012]      FIG. 1   b  is a perspective view of a closure mechanism according to an example embodiment of the present invention.  
         [0013]      FIG. 2  is an enlarged, fragmented, cross-sectional view of a closure mechanism according to an example embodiment of the present invention.  
         [0014]      FIG. 3   a  is an bottom view of a slider in accordance with the present invention.  
         [0015]      FIG. 3   b  is a cross-sectional view of the slider illustrated in  FIG. 3   a , taken along line b-b.  
         [0016]      FIG. 3   c  is a cross-sectional view of the slider illustrated in  FIG. 3   a , taken along line c-c.  
         [0017]      FIG. 3   d  is a bottom view of an alternate slider in accordance with the present invention.  
         [0018]      FIG. 3   e  is a cross-sectional view of the slider illustrated in  FIG. 3   d , taken along line e-e.  
         [0019]      FIG. 4   a  is an elevated, fragmented, perspective view of a recloseable package in accordance with an example embodiment of the present invention.  
         [0020]      FIG. 4   b  is an enlarged, fragmented, cross-sectional view of the closure mechanism according to the example embodiment of the present invention illustrated in  FIG. 4   a  taken along line  4   b - 4   b.    
         [0021]      FIG. 5   a  is an elevated, perspective view of a recloseable package in accordance with an example embodiment of the present invention, shown in the open position.  
         [0022]      FIG. 5   b  is an enlarged, cross-sectional view of the closure mechanism illustrated in  FIG. 5   a , shown in the open position and taken along line  5   b - 5   b.    
         [0023]      FIG. 6   a  is an elevated, perspective view of a recloseable package in accordance with an example embodiment of the present invention, shown in a partially closed position.  
         [0024]      FIG. 6   b  is an enlarged, cross-sectional view of the closure mechanism illustrated in  FIG. 6   a , shown in a partially closed position and taken along line  6   b - 6   b.    
         [0025]      FIG. 7   a  is an elevated, perspective view of a recloseable package in accordance with an example embodiment of the present invention, shown in the fully closed position.  
         [0026]      FIG. 7   b  is an enlarged, cross-sectional view of the closure mechanism illustrated in  FIG. 7   a , shown in the fully closed position and taken along line  7   b - 7   b.    
         [0027]      FIG. 8   a  is an elevated, perspective view of a recloseable package in accordance with an example embodiment of the present invention, shown in a partially open position.  
         [0028]      FIG. 8   b  is an enlarged, cross-sectional view of the closure mechanism illustrated in  FIG. 8   a , shown in a partially open position and taken along line  8   b - 8   b.    
         [0029]      FIG. 9  is an enlarged, fragmented, bottom view of the closure mechanism illustrated in  FIG. 8   a , shown in a partially open position.  
         [0030]      FIG. 10  is a largely schematic view of a horizontal form, fill and seal process for use in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0031]     The accompanying figure and the description that follows set forth this invention in its preferred embodiments. However, it is contemplated that persons generally familiar with resealable bags will be able to apply the novel characteristics of the structures and methods illustrated and described herein in other contexts by modification of certain details. Accordingly, the figures and description are not to be taken as restrictive on the scope of this invention, but are to be understood as broad and general teachings. When referring to any numerical range of values, such ranges are understood to include each and every number and/or fraction between the stated range minimum and maximum. Finally, for purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, and derivatives thereof shall relate to the invention, as it is oriented in the drawing figures.  
         [0032]      FIG. 1   a  illustrates an example packaging arrangement in the form of a resealable, flexible package  110 , for example, a polymeric package such as a plastic bag, having a resealable closure mechanism  114 , for example, interlocking profiled elements, constructed in accordance with the present invention. The flexible package  110  includes first and second opposed panel sections  116 ,  118 , typically made from a flexible, polymeric, plastic film, such as a low density polyethylene.  
         [0033]     With some manufacturing applications, the first and second panel sections  116 ,  118  are heat-sealed together along two side edges  120 ,  122  and meet at a fold line in order to form a three-edged containment section for a product within an interior  124  of the package  110 . In the embodiment shown, the fold line comprises the bottom edge  125  of the package  110 . Alternatively, two separate panel sections  116 ,  118  of plastic film may be used and heat-sealed together along the two side edges  120 ,  122  and at the bottom edge  125 . Access is provided to the interior  124  of the package  110  through a mouth  126  at a top edge  127  of the package. In the particular embodiment illustrated in  FIG. 1   a , the mouth  126  extends the width of the package  110 . The resealable closure mechanism  114  is illustrated at the mouth  126  of the flexible package  110 . Preferably, the cross-section of the closure mechanism  114  is continuous along its length across the mouth  126  of the package  110 . Alternatively, the closure mechanism  114  could be positioned on the package  110  at a location different from the mouth  126  of the package  110 , depending on the application needs for the package  110 .  
         [0034]     The resealable closure mechanism  114  can be one of a variety of closure mechanisms. In the particular embodiment illustrated in  FIGS. 1   b  and  2 , the resealable closure mechanism  114  is shown in the specific form of a zipper-type closure mechanism. By the term “zipper-type closure mechanism,” it is meant a structure having opposite interlocking or mating profiled elements that under the application of pressure will interlock and close the region between the profiles.  
         [0035]     In the embodiment shown in  FIG. 2 , the resealable closure mechanism  114  comprises first and second closure profiles  130 ,  131 . The first and second closure profiles  130 ,  131  are integrally formed with flanges  115 ,  117 , respectively. The first and second panel sections  116 ,  118  may be attached to the flanges  115 ,  117  by any appropriate means known to those skilled in the art. For example, the first and second panel sections  116 ,  118  may be formed separately, then heat sealed to the flanges  115 ,  117 .  
         [0036]     As shown in  FIG. 2 , the first closure profile  130  includes a first base strip  132  with a first interlocking member  134  extending therefrom. At a free end or tip of the first interlocking member  134  is a first hook or catch  174 . Likewise, the second closure profile  131  includes a second base strip  133  and a second interlocking member  135  extending therefrom. At a free end or tip of the second interlocking member  135  is a second hook or catch  175 . The second closure profile  131  also includes a guide member  139  extending from the second base strip  133 .  
         [0037]     The first and second closure profiles  130 ,  131  are designed and constructed to engage with one another to form the resealable closure mechanism  114 . The first interlocking member  134  of the first closure profile  130  extends from the base strip  132  an engagement distance. The second interlocking member  135  of the second closure profile  131  also extends from the base strip  133  an engagement distance. These engagement distances that the first and second interlocking members  134 ,  135  extend are sufficient to allow mechanical engagement, or interlocking, between the first interlocking member  134  of the first closure profile  130  and the second interlocking member  135  of the second closure profile  131 .  
         [0038]     In particular, the first catch  174  of the first interlocking member  134  hooks or engages with the second catch  175  of the second interlocking member  135 . Furthermore, the closure profiles  130 ,  131  are sealed together at their ends, such as first and second regions  156 ,  154  of  FIGS. 6   a - b  to further aid in aligning the closure profiles  130 ,  131  for interlocking. Pressure is applied to the closure profiles  130 ,  131  as they engage to form the openable sealed closure mechanism  114 . Pulling the first closure profile  130  and the second closure profile  131  away from each other causes the two closure profiles  130 ,  131  to disengage.  
         [0039]     The first and second closure profiles  130 ,  131  also include first and second upper flanges  184 ,  185 , respectively. The upper flanges  184 ,  185  are formed integrally with first and second base strips  132 ,  133 , respectively, and extend from the base strips toward the slider  20 . In operation, the slider  20  rests on and slides along the upper flanges  184 ,  185 .  
         [0040]      FIGS. 3   a - 3   c  illustrate an example slider  20  in accordance with the present invention. The slider  20  includes a top wall  23  and two side walls  22 ,  24  depending from the top wall  23 . The top wall  23  and the two side walls  22 ,  24  define a cavity in which the closure profiles  130 ,  131  (as shown in  FIG. 1   b ) are disposed when the slider is attached to the package  110 . Further, the slider  20  includes two ribs  26 ,  28  that extend towards each other from the two side walls  24 ,  22 , respectively. The two ribs function to force the two closure profiles  130 ,  131  together as the slider  20  is moved in a first direction along the closure mechanism  114 . The ribs  26 ,  28  are sized to allow the closure profiles  130 ,  131  enough room to pass through the cavity, yet still force the closure profiles  130 ,  131  to engage. To the same end, the two walls  22 ,  24  are tapered along their respective lengths to assist in forcing the closure profiles  130 ,  131  together as the slider  20  is moved in the first direction along the closure mechanism  114 .  
         [0041]     The slider  20  also includes a spreader  30  that functions to push apart the closure profiles  130 ,  131  as the slider is moved in a direction opposite the first direction along the closure mechanism  114 . In the embodiment illustrated in  FIGS. 3   a - 3   c , the spreader  30  comprises two flanges  31 ,  33 , both depending from the top wall  23  of the slider  20 . The two flanges  31 ,  33  are sized and arranged such that when the slider  20  is moved in the direction opposite the first direction along the closure mechanism  114 , the upper flanges  184 ,  185  are forced to pass around the spreader  30 . In this manner, the interlocking closure members  134 ,  135  are forced to disengage, thereby opening closure mechanism  114 .  
         [0042]     The flanges  31 ,  33  are also arranged to define a channel  35  through the spreader  30 . In other words, the channel  35  extends between the flanges  31 ,  33 . In the embodiment shown, the flanges  31 ,  33  are arranged to generally form a V-shape. However, the flanges  31 ,  33  do not contact each other at the point of the ‘V.’ Instead, the flanges are positioned and oriented to allow the upper flanges  184 ,  185  to pass through the point of the ‘V,’ and thus, between the flanges  31 ,  33 . Alternatively, the spreader  30  may be formed as a unitary device, with channel  35  being formed therethrough. In this embodiment, illustrated in  FIGS. 3   d  and  e , the spreader  30  is triangular in shape.  
         [0043]     The slider  20  also includes a first finger  38  that extends from the top wall  23  of the slider  20 . In operation, the first finger  38  will abut or engage the seal region  154  (as shown in  FIG. 5   a ) to inhibit the slider  20  from sliding off the resealable package  110 , as the slider  20  is moved in a direction effective to open the closure mechanism  114 . The slider  20  further includes a second finger  32  that extends from the top wall  23  of the slider  20 . The second finger  32  is located on the opposite end of the slider  20  from the first finger  38 . In operation, the second finger  32  will abut or engage the seal region  156  (as shown in  FIG. 5   a ) to inhibit the slider  20  from sliding off the resealable package  110  as the slider  20  is moved in a direction effective to close the closure mechanism  114 .  
         [0044]     Preferably, the slider  20  further includes two hook ends  51 ,  53  at the ends of side walls  24 ,  22  respectively. The hook ends  51 ,  53  are designed and sized to slideably engage with the bottoms of first and second closure profiles  131 ,  130 . The hook ends  51 ,  53  allow the slider  20  to move along the closure mechanism  114 , while preventing the slider  20  from falling or being easily pulled off of the closure mechanism  114 .  
         [0045]      FIGS. 4   a - b  illustrates the location of the upper flanges  184 ,  185  when the slider  20  is attached to the closure mechanism  114  for the first time in accordance with an embodiment of the present invention. The slider  20  is attached to the closure mechanism  114  while the closure mechanism  114  is at least partially open. Preferably, the slider  20  is attached to the closure mechanism  114  while the closure mechanism  114  is fully open. The walls  22 ,  24  of the slider  20  are spread apart and the slider  20  is set down on the upper flanges  184 ,  185 . As can be seen, the upper flanges  184 ,  185  are positioned between the ribs  26 ,  28  and are positioned in channel  35  which extends between the flanges  31 ,  33 . In older systems, the upper flanges  184 ,  185  would have to be placed between the ribs  26 ,  28  and around the outside of the spreader  30 . As can be appreciated, the severe angle change necessary to place the upper flanges  184 ,  185  in such a fashion poses manufacturing challenges. The present invention, by providing the channel  35  through the spreader  30 , solves this problem. As the angle change necessary to place the upper flanges  184 ,  185  between the ribs  26 ,  28  and in the channel  35  in this embodiment, aligning the upper flanges  184 ,  185  is simpler, leading to lower manufacturing costs.  
         [0046]     As shown in  FIGS. 5   a - b , the slider  20  is preferably attached at the end of the closure mechanism  114  that the slider  20  is positioned during normal operation when the closure mechanism  114  is fully open. The slider  20  is attached during the manufacturing of closure mechanism  114 , which is illustrated in  FIG. 10 .  
         [0047]      FIG. 10  illustrates a horizontal form, fill and seal (“HFFS”) process for manufacturing a closure mechanism  114  and a resealable bag  110  in accordance with the present invention. The first and second closure profiles  130 ,  131  (not shown individually in  FIG. 10 ) are provided in an engaged configuration as a continuous length of closure profile material  200 . Preferably, the closure profile material  200  is provided on a roll (not shown). The closure profile material  200  is then unwound and fed to the HFFS process.  
         [0048]     The first and second profiles  130 ,  131  are disengaged prior to the application of the slider  20 . The slider  20  is attached to the closure profile material  200  by a slider application station  210 . The slider application station  210  applies the slider  20  to the closure profile material  200  through the use of any appropriate means known in the art, for example, the apparatuses as described in U.S. Pat. Nos. 6,199,256 and 6,293,896, the entire contents of which are hereby incorporated by reference. While the apparatus disclosed in that application is suitable, it is noted that in the present invention, the upper flanges  184 ,  185  are positioned between the ribs  26 ,  28  and between the flanges  31 ,  33 , as described above, when it is applied by the slider application station  210 .  
         [0049]     Once the slider  20  is applied to the closure profile material  200 , the closure profile material  200  passes to the HFFS machine  250 . The material that comprises the side panels  116 ,  118  of resealable package  110  (as shown in  FIG. 1 ) is provided on a roll  220 . The material is unwound and passes to perforators  230  that score the material to facilitate later removal of a header section  101  (as is described below). The material then passes over a folding board  245  (as is known in the art) to form the two side panels  116 ,  118 . The folding board  245  includes a slitter that separates the material into side panels  116 ,  118 . The closure profile material  200  is positioned between the side panels  116 ,  118 . The side panels  116 ,  118  are then heat sealed to the flanges  115 ,  117  (not shown in  FIG. 10 ). The flanges  115 ,  117  are sealed to the side panels  116 ,  118  a predetermined distance below the perforations  231  so as to produce a header section  101  above the closure mechanism  114 . A suitable header section  101  construction is disclosed in U.S. Patent Application Ser. No. 60/222,132, filed Jul. 31, 2000, the entire contents of which are hereby incorporated by reference.  
         [0050]     The continuous line of packages moves to a pair of sealing bars  212  that seal the side panels  116 ,  118  together to form the sides  120 ,  122  of the resealable package  110  (as shown in  FIG. 1   b ), then to a sealing bar  213  that seals the side panels  116 ,  118  together to form the bottom edge  125 . The line of packages is moved beneath hopper or product-dispensing apparatus  240  that contains a product  241 . The hopper  240  dispenses a predetermined amount  341  of the product  241  into each resealable package  110 . Once the product  241  has been dispensed to package  110 , a seal bar  214  seals the top of header section  101 . The continuous line of packages is then divided into individual resealable packages  110  by a cut-off blade  215 .  
         [0051]     When a consumer purchases the package  110  containing the product  241 , the consumer removes the header section  101  at perforations  231 . As a result, the consumer has access to the product  241  through the open closure mechanism  114 . After the package  110  is open and a portion of the product  241  has been removed, it is desirable to close the closure mechanism  114 , as shown in  FIGS. 6   a - b . The slider is moved along the closure mechanism  114  in the direction opposite the direction it was moved in order to open the closure mechanism  114 . As the slider  20  moves along the closure mechanism  114 , the closure profiles  130 ,  131  are forced together and the interlocking closure members  134 ,  135  are forced to engage. The slider  20  is moved until it comes to rest in the notch  50 , as illustrated in  FIGS. 7   a - b . As the slider  20  comes to rest in the notch  50 , the ends  190 ,  191  of the upper flanges  184 ,  185  that form a side of the notch  50  pass fully through the channel  35  of the spreader  30 . In this way, the closure profiles  130 ,  131  are engaged along their entire lengths.  
         [0052]     When it is desirable to open the closure mechanism  114  after the slider  20  has come to rest in the notch  50 , the slider  20  is moved in the direction it was moved when it was first attached to the closure mechanism  114 , as shown in  FIGS. 8   a - b . Due to the triangular shape of the spreader  30 , when the spreader  30  is moved against the ends  190 ,  191  of the closure profiles  130 ,  131 , the upper flanges  184 ,  185  are directed around the outside of the spreader  30 , along the flanges  31 ,  33 , as shown in  FIG. 9 . The upper flanges  184 ,  185  are directed around the outside of the spreader  30  in all subsequent openings and closings of the package.  
         [0053]     Having described the presently preferred embodiments, it is to be understood that the invention may be otherwise embodied within the scope of the appended claims.