Abstract:
A method of making a resealable package is provided. The method comprises providing a closure mechanism, the closure mechanism comprising first and second closure profiles, the first and second closure profiles constructed and arranged to selectively engage, and wherein the first and second closure profiles are engaged. The method further comprises providing a pair of panels comprising a flexible polymeric material, inserting a wedge between the closure profiles, disengaging the closure profiles; and attaching the closure mechanism to the pair of side panels. Various embodiments of opening devices are also presented.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a Divisional of application Ser. No. 10/427,716, filed on Apr. 30, 2003. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to a method of making polymer packages, for example, plastic bags. In particular, the present invention relates to a methods and apparatuses relating to closure mechanisms for 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. Typically a slider device used for opening the closure mechanism is attached to the closure mechanism while the closure profiles are disengaged. This facilitates filling of the package with product after the slider is attached. However, attaching the slider to a closure mechanism in an open state results in difficulty in handling and aligning the pair of closure profiles during manufacturing. If the slider device is attached to the closure mechanism while the closure mechanism is closed, the closure mechanism must be opened before the package can be filled. Prior methods of opening the closure mechanism, including manually opening the closure mechanism, have proved to be inefficient from a manufacturing standpoint.  
           [0005]    It is therefore desirable to attach the slider device to the closure mechanism while the closure mechanism is in a closed state, and to provide a method and apparatus for automatically opening the closure mechanism after the slider device has been attached. Alternately, the slider device may be attached after the closure mechanism has been opened. Further, the opening methods and apparatus of the present invention can be applied to a closure mechanism without a slider, such as a traditional “press-to-close” zipper.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with the present invention, a method of making a resealable package is provided. The method comprises providing a closure mechanism, the closure mechanism comprising first and second closure profiles, the first and second closure profiles constructed and arranged to selectively engage, and wherein the first and second closure profiles are engaged. The method further comprises providing a pair of panels comprising a flexible polymeric material, providing a means to open the closure profiles, such as inserting a wedge between the closure profiles, to disengage the closure profiles; and attaching the closure mechanism to the pair of side panels. The opening of the closure profiles and attachment of the closure mechanism to the side panels may occur substantially simultaneously. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    For the present invention to be clearly understood and readily practiced, the present invention will be described in conjunction with the following figures, wherein like reference characters designate the same or similar elements, which figures are incorporated into and constitute a part of the specification, wherein:  
         [0008]    The various features and benefits of the present invention are apparent in light of the following detailed description and the accompanying drawings, in which:  
         [0009]    [0009]FIG. 1 is a perspective view of a flexible, resealable package manufactured in accordance with an embodiment of the present invention.  
         [0010]    [0010]FIG. 2 is a schematic view of a process of manufacturing a resealable package in accordance with an embodiment of the present invention.  
         [0011]    [0011]FIG. 3 is a perspective view of a slider attachment device and a device for opening a closure mechanism used in accordance with an embodiment of the present invention.  
         [0012]    [0012]FIG. 4 a  is a top view of the device for opening a closure mechanism illustrated in FIG. 3.  
         [0013]    [0013]FIG. 4 b  is an elevated, side view of the device for opening a closure mechanism illustrated in FIG. 3.  
         [0014]    [0014]FIG. 4 c  is an alternate perspective view of the device for opening a closure mechanism illustrated in FIG. 3.  
         [0015]    [0015]FIG. 4 d  is an cross-sectional view of the device for opening a closure mechanism illustrated in FIG. 3 taken along line  4   d - 4   d  (shown in FIG. 4 b ).  
         [0016]    [0016]FIG. 5 is an elevated, side view of a alternate device for opening a closure mechanism used in accordance with an embodiment of the present invention.  
         [0017]    [0017]FIG. 6 a  is an elevated, side view of a wedge used as part of the device for opening a closure mechanism illustrated in FIG. 5.  
         [0018]    [0018]FIG. 6 b  is an elevated, end view of a wedge used as part of the device for opening a closure mechanism illustrated in FIG. 5.  
         [0019]    [0019]FIG. 6 c  is a perspective view with a cross-sectional view insert showing an alternate embodiment of a wedge that can be used in conjunction with the apparatus and methods described herein.  
         [0020]    [0020]FIG. 6 d  is a schematic frontal view of the plow and guide legs of the wedge shown in FIG. 6 c.    
         [0021]    [0021]FIG. 6 e  is a perspective view showing the relational position between the wedge of FIG. 6 c  and a closure mechanism prior to opening the closure mechanism.  
         [0022]    [0022]FIG. 6 f  is a perspective view showing the wedge of FIG. 6 c  passing into a closure mechanism to separate the closure profiles thereby opening the closure mechanism.  
         [0023]    [0023]FIG. 7 is an elevated, side view of the device for opening a closure mechanism illustrated in FIG. 5, illustrating its operation.  
         [0024]    [0024]FIG. 8 is an elevated, side view of a alternate device for opening a closure mechanism used in accordance with an embodiment of the present invention.  
         [0025]    [0025]FIG. 9 is a top view of the device for opening a closure mechanism illustrated in FIG. 8.  
         [0026]    [0026]FIG. 10 a  is an end view of the device for opening a closure mechanism illustrated in FIG. 8.  
         [0027]    [0027]FIG. 10 b  is an end view of the device for opening a closure mechanism illustrated in FIG. 8, illustrating the use of sealing bars in accordance with an embodiment of the present invention.  
         [0028]    [0028]FIGS. 11 a - c  are cross-sectional views of an opening device and method that employ a perpendicular external force to open a closure mechanism.  
         [0029]    [0029]FIG. 12 is a cross-sectional view of an opening device and method that use a channel wedge to open a closure mechanism.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    [0030]FIG. 1 illustrates an example of a resealable, flexible package  20  having a closure mechanism  41  with first and second closure profiles  23 ,  25  and a slider device  11  to open and close the profiles  23 ,  25 .  
         [0031]    The resealable package  20  includes first and second opposed panel sections  31 ,  33  made from a flexible, polymeric film. For some manufacturing applications, the first and second panel sections  31 ,  33  are heat-sealed together along two edges  35 ,  37  and meet at a fold line  39  in order to form a three-edged containment section for a product within the interior of the package  20 . The fold line comprises the bottom edge  39 . Alternatively, two separate panel sections  31 ,  33  of polymeric film may be used and heat-sealed together along the two edges  35 ,  37  and at the bottom  39 .  
         [0032]    The resealable package  20  also includes a closure mechanism  41  made in accordance with an embodiment of the present invention. The closure mechanism  41  includes first and second closure profiles  23 ,  25 . The first and second closure profiles  23 ,  25  may be of any appropriate design known in the art. Example closure profiles are disclosed in U.S. Pat. Nos. 5,983,466, 5,947,603, and 6,217,215.  
         [0033]    In certain embodiments, a slider device  11  is mounted on the closure mechanism  41  to facilitate the opening and closing of the closure mechanism  41 . Slider devices and how they function to open and close such mechanisms, in general, are taught, for example, in U.S. Pat. Nos. 5,063,644, 5,301,394, 5,442,837 and 5,664,229, each of which is incorporated by reference herein, in its entirety. A preferred slider device is taught in U.S. Pat. Nos. 6,293,701 and D434, 345 each of which is incorporated by reference herein, in its entirety.  
         [0034]    In embodiments that include a slider device, a notch  52  is preferably disposed within the closure mechanism  41 . The notch  52  is designed to provide a “park place” into which the slider  11  settles when the closure mechanism  41  is sealed. The notch  52  decreases the chances of an incomplete interlock between the first and second closure profiles  23 ,  25 . Example notches are disclosed, for example, in U.S. Pat. Nos. 5,067,208 and 5,301,395, each of which is incorporated by reference herein, in its entirety.  
         [0035]    [0035]FIG. 2 illustrates a schematic example of a horizontal form, fill and seal (“HFFS”) process for manufacturing a resealable package  20  in accordance with the present invention. The HFFS process described in U.S. Pat. No. 6,293,896, which is incorporated by reference herein, in its entirety, is substantially similar to that described and shown herein with the obvious variation that the package of the present invention is inverted (i.e. the formation and filling in the present invention is from the top) whereas the formation and filling in the &#39;896 patent occurs from the bottom. The first and second closure profiles  23 ,  25  (not shown individually in FIG. 2) are provided in an engaged configuration as a continuous length of closure profile material  50 . Preferably, the closure mechanism material  50  is provided on a roll (not shown). The closure mechanism material  50  is unwound and fed to the HFFS process.  
         [0036]    The slider  11  is attached to the closure mechanism material  50  by a slider application station  60 . The slider application station  60  applies the slider  11  to the closure mechanism material  50  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, each of which are hereby incorporated by reference herein, in its entirety. The slider application station  60  may also be used to notch the closure profile material in order to provide the notch  52  (as shown in FIG. 1), as disclosed in U.S. Pat. No. 6,199,256.  
         [0037]    After the slider  11  is applied to the closure mechanism material  50 , the closure mechanism material  50  passes to the HFFS machine  250 . The material that comprises the side panels  31 ,  33  of resealable package  20  (as shown in FIG. 1) is provided on a roll  220 . The material is unwound and may optionally pass to perforators  230  that score the material to facilitate later removal of a header section  101 . The material then passes over a folding board  245  (as is known in the art) to form the two side panels  31 ,  33 . The folding board  245  may include a slitter (not shown), if e.g. the HFFS machine is operated in a different orientation.  
         [0038]    In the embodiments of the invention illustrated in FIGS. 3-8, the first and second closure profiles  23 ,  25  are disengaged by the closure mechanism opening apparatus  70  prior to the closure mechanism material  50  being attached to the first and second side panels  31 ,  33 . Alternately, the closure mechanism may be disengaged substantially simultaneously with the closure mechanism being attached to the side panels (i.e. disengagement and attachment as a single step), or disengagement may even occur after attachment to the side panels.  
         [0039]    An example closure mechanism opening apparatus  70  is illustrated in FIGS. 4 a - 4   d.  The closure mechanism opening apparatus  70  comprises a rod  76  and a piston  72  that causes selective reciprocating movement of the rod  76 . A preferred rod  76  and piston  72  are manufactured by DE-STA-CO Industries, 31791 Sherman Drive, Madison Heights, Mich. 48071, Model 816, made of steel and aluminum. The rod  76  and piston  72  are preferably mounted on a stand-off base  74 .  
         [0040]    The rod  76  is operably connected to a wedge  80  such that as rod  76  moves, the wedge  80  moves. For example, if the piston is activated to move the rod in a reciprocating manner, the wedge would move in a similar manner. As best shown in FIG. 4 d,  the wedge  80  is preferably tapered along its bottom edge to allow it to penetrate between the closure profiles  23 ,  25 . A set of guide members  82  are attached at both ends of the wedge  80 . The guide members  82  act to align the closure mechanism material  50  as it passes through the closure mechanism opening apparatus  70 . The guide members  82  are preferably designed and arranged to allow the closure mechanism material  50  to pass between them and align the closure mechanism material  50  beneath the wedge  80  or in similar proximity to the wedge, depending on the spatial orientation of apparatus  70 . The guide members  82  are attached to the wedge  80  by any means known in the art, for example, by machined screws or by welding. Alternatively, the wedge  80  and guide members  82  may be formed integrally.  
         [0041]    The closure mechanism opening apparatus  70  further comprises a three-sided guide channel  78 . The guide channel  78  preferably has a support blade  84  attached to one of its sides as best seen in FIG. 4 d.  The stand-off base  74  is attached to the top of guide channel  78 , which has an aperture  81  through its top side as shown in FIG. 4 a.  In this way, the selective reciprocating movement of the rod  76  causes the wedge  80  and guide members  82  to move up and down through the aperture  81  in the top of the guide channel  78 .  
         [0042]    Preferably, the closure mechanism opening device  70  further includes a support blade  84  that is designed and arranged such that when the closure mechanism material  50  passes through the guide channel  78 , the closure mechanism material  50  straddles or rides on the blade  84 , which supports the closure mechanism material  50 . As stated previously, the blade  84  preferably assists in aligning the closure mechanism material  50  beneath the wedge  80 .  
         [0043]    In operation, a length of the closure mechanism material  50  that corresponds to the length of a resealable package  20  passes into the guide channel  78 , on top of blade  84 . The progress of the closure mechanism material  50  is stopped. The piston  72  is then actuated whereby the rod  76  is extended. This causes the wedge  80  and guide members  82  to be moved through the aperture  81  of the top of the guide channel  78 . The guide members  82  are forced along the outside of the closure mechanism material  50 , and the wedge  80  is disposed between the closure profiles  23 ,  25 . As the wedge  80  is moved downward by the rod  76 , the wedge  80  forces closure profiles  23 ,  25  to disengage along the length of the wedge  80 . The wedge  80  is then withdrawn from the closure mechanism material  50 . The opened closure mechanism material  50  is then advanced in an opened state for further processing, as is described below.  
         [0044]    An alternate example embodiment of a closure mechanism opening apparatus  70  is illustrated in FIGS. 5-7. In this embodiment, the guide channel  78  and the blade  84  are designed and function in a similar manner as in the embodiment illustrated in FIGS. 3-4 d.  The closure mechanism opening apparatus  70  further comprises a piston  92 , a brace  98 , and a wedge  100 . The piston  92  includes a rod  96  that may move in a selective reciprocating manner. In this embodiment, the wedge  100  is generally shaped as a sector of a circle as shown in FIG. 6 a.  The wedge  100  includes an arm  106  that extends from the corner of the sector that would otherwise correspond with the center of the circle from which the sector would be taken. The arm  106  includes an opening  108  through which a pin or rod may be inserted in such a way as to allow the wedge  100  to rotate around such a pin or rod. The arm  106  is operably connected to the rod  96  such that when the rod  96  is extended from the piston  92 , the wedge  100  rotates, preferably in the direction of the arrow R shown in FIG. 7. Likewise, when the rod  96  is withdrawn, the wedge  100  will rotate in a direction opposite that in which it rotates when the rod  96  is extended. The wedge  100  is preferably attached to the channel  78  by a brace  98 . In the embodiment illustrated in FIG. 5, the brace  98  includes an opening that may be aligned with the opening  108  through the wedge  100 . In this way, a pin or rod that is inserted through the opening  108  also serves to attach the wedge  100  to the brace  98 . The brace  98  is also preferably attached to the piston  92  by way of brackets  94 ,  95 .  
         [0045]    As best shown in FIG. 6 b,  the curved edge  102  of the wedge  100  is tapered so that its leading edge  101  narrows to a point. The curved edge  102  also includes a pair of guide members  104  that are adjacent the leading edge  101 . Similar to the embodiment described above, and as shown in FIG. 7, a length of the closure mechanism material  50  that corresponds to the length of a resealable package  20  passes into the guide channel  78 , on top of blade  84 . The progress of the closure mechanism material  50  is stopped. The piston  92  is then actuated whereby the rod  96  is extended. This causes the wedge  100 , including guide members  104 , to rotate through an aperture (not shown) in the top of the guide channel  78 . The guide members  104  are forced along the outside of the closure mechanism material  50 , and the curved edge  102  of the wedge  100  is disposed between a portion of the length of the closure profiles. As the wedge  100  rotates, the curved edge  102  of the wedge  100  forces closure profiles to disengage. After the closure profiles disengage, the wedge  100  rotates in the opposite direction, thereby withdrawing from the closure mechanism material  50 . As one skilled in the art will recognize, an alternate embodiment to that illustrated in FIGS. 5-7 would be a blade designed to rotate in a complete 360° arc as it passes through the closure mechanism to disengage the closure profiles. The opened closure mechanism material  50  is then advanced in an opened state for further processing, as is described below.  
         [0046]    [0046]FIGS. 6 c - f  illustrate an alternate embodiment of a wedge  200  for use with the opening apparatus  70 , for example, as shown in FIG. 5. As described above, the various methods of opening a closure mechanism with the embodiment illustrated in FIGS. 5-7 may include both reciprocal and rotational movement of the wedge ( 100 ,  200 ). For example, reciprocal movement is such that the wedge enters the closure mechanism in one direction (e.g. “R” in FIG. 7) and, after opening the closure mechanism, is removed from the closure mechanism in the opposite direction. Rotational movement of the wedge ( 100 ,  200 ) occurs by rotating the wedge ( 100 ,  200 ) with a controlled mechanical rotating device (not shown) such that the wedge moves in circular direction and passes into and out of the closure mechanism as the wedge ( 100 ,  200 ) scribes an arc at some aspect of circle “C” as depicted in FIG. 6 e - f.    
         [0047]    With reference to FIG. 6 c,  wedge  200  is shown consisting of a body  210 , an opening plow  220  and guide legs  230 ,  232 . As shown FIG. 6 d,  the plow  220  is preferably centered along a travel path “P” passing between guide legs  230 ,  232 . This arrangement of the plow  220  with the guide legs  230 ,  232  facilitates the cooperation of these structures such that during operation the guide legs  230 ,  232  capture the closure mechanism and align the plow  220  to pass into the closure mechanism thereby opening the closure mechanism. It is preferable if the plow  220  has a tapered leading edge to facilitate its entry into the closed closure mechanism.  
         [0048]    As further illustrated in FIGS. 6 d - 6   f,  the wedge  200  is preferably rotated into the closure mechanism material  50  to thereby separate (open) closure profiles  23 ,  25 . After opening, the opened closure mechanism can be advanced for further processing (e.g. attachment, filling, etc.).  
         [0049]    A further preferred embodiment of the invention is illustrated in FIGS. 8-10 b.  In this embodiment, the guide channel  78  and the blade  84  are designed and function in a similar manner as in the embodiments described above. In this embodiment, the channel  78  may also include an opening  79  (e.g. shown in FIGS. 10 a - 10   b ) through which a pair of sealing bars,  130 ,  132  may pass, as described below. In this embodiment, the closure mechanism opening apparatus  120  comprises a rod  124  and a piston  122  that causes selective reciprocating movement of the rod  124 . A preferred rod  124  and piston  122  are manufactured again, by DE-STA-CO Industries.  
         [0050]    In the embodiment illustrated in FIGS. 8-10 b,  the wedge  126  is generally cylindrical in shape, although one end may be tapered to facilitate opening of the closure mechanism material  50 . The piston  122  and rod  124  are held in place above the guide channel  78  by brace  134 .  
         [0051]    This embodiment may take advantage of the fact that, when certain types of sliders  11  are attached to the closure mechanism material  50 , a small opening  51  (as shown in FIG. 9) is created between the closure profiles  23 ,  25  immediately adjacent to the slider  11 .  
         [0052]    In operation, a length of the closure mechanism material  50  that preferably corresponds to the length of a resealable package  20  passes into the guide channel  78 , on top of blade  84 . The progress of the closure mechanism material  50  is stopped at a point when the opening  51  is directly beneath the wedge  126 . The piston  122  is then actuated whereby the rod  124  is extended. This causes the wedge  126  to be moved through the top of the guide channel  78 . The wedge  126  is disposed in the opening  51  between the closure profiles [ 23 ,  25 ].  
         [0053]    Preferably, the guide channel  78  is aligned with sealing bars  130 ,  132  that are used to seal the side panels  31 ,  33  to the closure profiles  23 ,  25  such that the sealing bars  130 ,  132  may pass through the opening  79  in the guide channel  78 . In this embodiment, it is preferred to have the sealing bars  130 ,  132  move together to seal the side panels  31 ,  33  to the closure profiles  23 ,  25  at substantially the same time that the wedge  126  is inserted into the opening  51 . The sealing bars  130 ,  132  are then withdrawn from the guide channel  78 . The closure mechanism material  50  is then advanced the length of one package  20  with the wedge  126  still inserted between the closure profiles  23 ,  25 . As will be understood by one of ordinary skill in the art, this movement will cause the engaged portion of the closure mechanism material  50  to disengage. After the closure mechanism material  50  has been advanced, and thus disengaged along the length of one package  20 , the wedge  126  is withdrawn from the closure mechanism material  50 . The opened closure mechanism material  50  continues in an opened state for further processing, as is described below.  
         [0054]    In the embodiments illustrated in FIGS. 3-7, the closure mechanism material  50  is opened, but not yet sealed to the side panels  31 ,  33 . In the embodiment illustrated in FIGS. 8-10 b,  the closure mechanism material  50  is positioned between the side panels  31 ,  33 . The side panels  31 ,  33  are then heat sealed to the closure profiles  23 ,  25  by sealing bars  130 ,  132 . The various embodiments of this invention contemplate that opening of the closure mechanism  41  and sealing of the closure profiles  23 ,  25  to the side panels  31 ,  33  can occur either sequentially (e.g. opening followed by sealing or sealing followed by opening) or simultaneously (i.e. opening and sealing at the same station and substantially at the same time).  
         [0055]    Two additional embodiments are schematically illustrated in FIGS. 11-12, each of which incorporates a force that is external to the closure mechanism  41  to open the closure profiles  23 ,  25 . With reference to FIG. 11 a,  a cross-sectional view of an alternate closure mechanism  41  is shown in a closed or engaged position. The engaged mechanism  41  is positioned between two opposing flat surfaces  140 ,  141 , on moveable wedges  150 ,  151 . Upon activating the opening apparatus  70  illustrated in FIG. 11 a,  the moveable wedges  150 ,  151  move towards each other, as best shown in FIG. 11 b,  with sufficient force to “pinch” the closure profiles  23 ,  25  of closure mechanism  41  into an open position. The pinching occurs as surfaces  140 ,  141  come in contact with closure profiles  23 ,  25 . Following this “pinch-open” action, the wedges  150 ,  151  move apart, as shown in FIG. 11 c,  and reset for admission of the next closure mechanism to be opened.  
         [0056]    One of skill in the art will recognize many variations of practicing the invention illustrated in FIGs. 11 a - 11   c.  For example, one of the moveable wedges ( 150 ) could be replaced with an immovable surface such that only one moveable wedge ( 151 ) would have to move and pinch the closure mechanism against the immovable surface to open these closure profiles.  
         [0057]    A further embodiment utilizing a force external to the closure mechanism to open the closure profiles is illustrated in cross-section in FIGS. 12 a - b.  In this embodiment, a channel wedge  160  is placed over closure profile  50  (FIG. 12 a ), such that said action of placement forces open the closure profiles  23 ,  25  (FIG. 12 b ). Preferably, the interior dimension  162  of the channel wedge  160  is proportioned appropriately to accomplish the opening of the closure profiles  23 ,  25  without disrupting the integrity of the package (not shown).  
         [0058]    It is contemplated that the channel wedge embodiment operates in a substantially similar manner the method as previously described for the wedge illustrated in FIGS. 4 a - 4   d.  The main difference between these distinct embodiments is that the closure mechanism illustrated in FIGS. 4 a - 4   d  lends itself to being split-open by inserting a wedge between the closure profiles, while the closure mechanism of FIG. 12 is opened by a force applied externally to the closure profiles.  
         [0059]    Referring back to FIG. 2, after opening the closure mechanism in accordance with the invention disclosed herein, the continuous line of packages continues to sealing bars  112  that seal the sides  31 ,  33  of the package  20 . The continuous line of packages then pass under hopper  114  that contains the product to be placed in package  20 . As the packages pass under the hopper  114 , product  241  passes through the mouth of the header section  101  and into the interior of the package  20 . In certain embodiments, the mouth of the header section  101  is then sealed by sealing bars  116  to form a tamper-evident structure. Finally, the continuous line of packages is separated into individual packages by cutting knife  118 .  
         [0060]    While specific embodiments and methods for practicing this invention have been described in detail, those skilled in the art will recognize various manifestations and details that could be developed in light of the overall teachings herein. Accordingly, the particular mechanisms disclosed are meant to be illustrative only and not to limit the scope of the invention which is to be given the full breadth of the following claims and any and all embodiments thereof.