Abstract:
A flexible zipper intended for use in a package containing powder or other particulate matter. The zipper is designed to be resistant to clogging of the interlocking profiles with powder. This flexible zipper has first and second profiles that interlock in a closed zipper state to define a space therebetween. The space extends in a longitudinal direction, i.e., along the length of the zipper. The bases of both profiles are provided with apertures for enabling powder or other particulate matter trapped in the space between the profiles to pass into the interior volume of a package.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention pertains to a zipper for a reclosable package, such as a bag manufactured by a form, fill and seal apparatus, wherein the base of at least one of the zipper strips has apertures that allow packaged product, such as powder, to pass through the apertures and return to the interior volume of the reclosable package.  
           [0002]    In the prior art, it is known to use a zipper with a female profile and a male profile in the manufacture of a reclosable package, such as a bag manufactured by a form, fill and seal apparatus. However, it is further known that if the reclosable package is filled with a fine powder product, then the fine powder or particulate matter can enter the female profile and degrade the performance of the zipper by blocking insertion of the male profile. Furthermore, if the user cleans this fine powder product from the female profile, this powder tends to be discarded rather than returned to the reclosable package. Moreover, such cleaning of the female profile can tend to contaminate any fine powder product that is returned to the reclosable package.  
           [0003]    U.S. Pat. No. 6,299,353, entitled “Zipper for Reclosable Container with Apertures Passing Through Female Profile” and assigned to the assignee of the instant application, discloses a zipper with a female profile wherein spaced apertures are formed in the base thereof. The apertures communicate with the powder-containing interior volume of a reclosable package. When fine powder product becomes lodged within the female profile, an arrow-shaped male element of the male profile can push the lodged fine powder product through the apertures in the base of the female profile, to return the powder to the interior volume of the reclosable package. Since the legs of the female profile, as well as the male element of the male profile, remain intact, there is no degradation of the sealing provided by the zipper. Moreover, the direction of travel of the fine powder product through the apertures is substantially the same as the travel direction of the male element as it enters the female profile. As the fine powder product can be returned to the interior volume of the reclosable package without directly contacting the consumer, the fine powder product tends to be returned to the interior volume of the reclosable package free of contamination. To prevent powder from entering the female profile through the apertures, the female profile material that is cut to form the apertures may be left attached along an edge, thereby forming a flap that can serve as a simple one-way valve to permit powder to be removed from the female profile via the apertures, while preventing powder from entering the female profile via the apertures.  
           [0004]    Flexible plastic zippers in which the male profile does not have an arrow shape are well known. For example, in one type of flexible zipper, the female profile comprises a pair of spaced legs or hooks having inwardly pointing detents, while the male profile comprises a pair of spaced legs or hooks having outwardly pointing detents, When the male profile penetrates the female profile, both legs of the male profile are located in the space between the legs of the female profile, with the detents of the male and female profiles being latched or interlocked to hold the zipper closed. For zippers of this type that are incorporated in packaging containing powder or other particulate matter, the male profile as well as the female profile can become clogged with powder or particles. Therefore, it would be highly desirable to redesign such zippers to be powder-resistant, i.e., the zipper should be designed to prevent the male profile, as well as the female profile, from becoming clogged with powder or other particulate matter.  
         BRIEF DESCRIPTION OF THE INVENTION  
         [0005]    The present invention is directed to a flexible zipper intended for use in a package containing powder or other particulate matter. The zipper is designed to be resistant to clogging of the interlocking profiles with powder. The invention is also directed to packages incorporating such powder-resistant zippers.  
           [0006]    The flexible zippers disclosed herein comprise first and second profiles that interlock in a closed zipper state to define a space therebetween. The space extends in a longitudinal direction, i.e., along the length of the zipper. In some embodiments, the bases of both profiles are provided with apertures for enabling powder or other particulate matter trapped in the space between the profiles to pass into the interior volume of a package. In other embodiments, one or more posts are incorporated in one profile for pushing powder out of apertures formed in the same profile or in the other profile.  
           [0007]    In accordance with some embodiments of the invention, the first and second profiles are male and female profiles respectively. The male profile comprises a plurality of apertures in direct communication with the longitudinal space formed between the male and female profiles. Preferably, these apertures are arranged at spaced intervals along a longitudinal axis of the male profile. The male profile comprises a base and first and second profiled members connected to the base. In accordance with the disclosed embodiments, the first and second profiled members have hook-shaped profiles with outwardly pointing detents and are spaced apart in mutually parallel relationship. The plurality of apertures is located between respective connections of the base to first and second profiled members.  
           [0008]    Similarly, the female profile comprises a base, a plurality of apertures in direct communication with the longitudinal space, and third and fourth profiled members connected to its base. However, the third and fourth profiled members have hook-shaped profiles with inwardly pointing detents that latch behind the outwardly pointing detents of the male profile to lock the male profile in the closed position. The third and fourth profiled members of the female profile are spaced apart in mutually parallel relationship. The apertures formed in the female profile are located between respective connections of its base to the third and fourth profiled members.  
           [0009]    Another aspect of the invention is a flexible zipper comprising male and female profiles that interlock in a closed zipper state to define a space therebetween that extends in a longitudinal direction. The male profile comprises a first base comprising a plurality of apertures in direct communication with the space, and first and second profiled members connected to and projecting generally transverse relative to the first base on opposite sides of the apertures. The female profile comprises a second base and third through fifth profiled members connected to and projecting generally transverse relative to the second base. The fourth profiled member is between the third and fifth profiled members and projects between the first and second profiled members when the male and female profiles are interlocked.  
           [0010]    Yet another aspect of the invention is a flexible zipper comprising male and female profiles that interlock in a closed zipper state to define a space therebetween that extends in a longitudinal direction. The male profile comprises a first base and first and second profiled members connected to and projecting generally transverse relative to the first base, part of the space lying between the first and second profiled members. The female profile comprises a second base comprising a plurality of apertures in direct communication with the space, third and fourth profiled members connected to and projecting generally transverse relative to the second base on opposite sides of the apertures, and a plurality of spaced posts arranged in alternating sequence with the apertures and projecting between the first and second profiled members when the male and female profiles are interlocked.  
           [0011]    In accordance with further alternative embodiments, during formation of the apertures in the male and female profiles, the material is cut in a manner that leaves flaps of material attached along one or more edges of each aperture. Also, the outer surface of the base of each profile can be provided with knobs adjacent to or near each aperture that project outward.  
           [0012]    In accordance with further embodiments of the invention, a flexible zipper having apertured male and female profiles is incorporated in a package that, when filled, will contain powder or other particulate matter. Each apertured zipper profile comprises a base having an extension flange that extends away from the interior volume of the receptacle. In other words, the extension flanges lie on the side of the interlocked zipper elements that is opposite to the side where the interior volume of the package is located. The edge sections of the front and rear body panels (comprising sheets of film) of the package are heat-fused, bonded or otherwise attached to the respective extension flanges. The result is that the space formed by the interlocked male and female profiles is in communication with the interior volume of the package via the apertures. Preferably, knobs are provided on the outer surfaces of the bases of the zipper profiles to maintain the communication paths from the longitudinal space formed by the male and female profiles to the interior volume of the package. As a result, powder or other particulate matter trapped in the longitudinal space between the interlocked male and female profiles can pass through the apertures and thereby be returned, without be contaminated, to the mass of powder or other particular matter contained in the interior volume of the package.  
           [0013]    The invention is not limited to zippers having a male profile with outwardly pointing detents and a female profile with inwardly pointing detents. Instead, one profile may comprise first and second mutually parallel locking members (e.g., having hook-shaped profiles), each of the first and second members having a respective detent pointing in one and the same direction, while the other complementary profile will comprise third and fourth mutually parallel locking members (e.g., having hook-shaped profiles), each of the third and fourth members having a respective detent pointing in the opposite direction. In such embodiments, each profile base could be provided with a row of apertures in the region between its parallel locking members, which apertures would provide a path for powder or other particulate matter trapped between the profiles to be returned to the interior volume of the package.  
           [0014]    Other aspects of the invention are disclosed and claimed below.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a schematic showing a cross-sectional view of the male and female profiles of a prior art zipper, showing powder product passing through apertures in the female profile to the interior of the reclosable package. The male profile has an arrow shape.  
         [0016]    [0016]FIG. 2 is a schematic showing an isometric view of the male and female profiles of a powder-resistant flexible zipper in accordance with one embodiment of the invention.  
         [0017]    [0017]FIG. 3 is a schematic showing a cross-sectional view of the powder-resistant flexible zipper of FIG. 2 incorporated in a reclosable package in accordance with an embodiment of the invention.  
         [0018]    [0018]FIG. 4 is a schematic showing an isometric view of the male and female profiles of a powder-resistant flexible zipper in accordance with another embodiment of the invention.  
         [0019]    [0019]FIGS. 5 and 6 are schematics showing respective isometric views (from opposite sides) of the female profile of a powder-resistant flexible zipper in accordance with a further embodiment.  
         [0020]    [0020]FIG. 7 is a schematic showing an isometric view of the male and female profiles of a powder-resistant flexible zipper in accordance with yet another embodiment of the invention.  
         [0021]    [0021]FIG. 8 is a schematic showing a cross-sectional view of a prior art female zipper profile provided with a flapped aperture. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    Reference will now be made to the drawings, in which similar elements in different drawings bear the same reference numerals. The structure of a prior art reclosable bag having a powder-resistant flexible plastic zipper will be generally described with reference to FIG. 1. Then the structure of a powder-resistant zipper in accordance with a first embodiment will be described with reference to FIGS. 2 and 3; and the structure of a powder-resistant zipper in accordance with a second embodiment will be described with reference to FIGS.  4 - 6 . It should be understood that the powder-resistant zippers shown in FIGS. 2 and 4 can be installed in a reclosable bag in the manner shown in FIG. 3 by any conventional means, such as heat fusion, adhesive, and bonding strips.  
         [0023]    [0023]FIG. 1 is a cross-sectional view of a prior art zipper attached to a package or bag  100  (only partly depicted). Bag  100  is typically formed from an upper film sheet  102  and a lower film sheet  104  (the terms “upper” and “lower” are used with respect to the orientation shown in FIG. 1). Upper film sheet  102  and lower film sheet  104  are typically sealed together or folded at three sides, so as to form a mouth  101  of the bag  100  at a fourth side. Typically, a form, fill and seal apparatus (not shown) is used to manufacture bag  100 . The zipper is attached to the mouth  101  and can be manipulated to open and close the bag  100 . This prior art zipper comprises an extruded zipper half  12  having a male profile and an extruded zipper half  14  having a female profile. For the sake of brevity, these zipper halves will hereinafter be referred to as the “male profile” and the “female profile”. Male profile  12  comprises a planar base  16  and a male element having a shaft  18  extending perpendicularly from the planar base  16 . Shaft  18  terminates with an enlarged head  20  having outwardly pointing detents  22  for engaging the female profile  14 . As shown in FIG. 1, a portion of planar base  16  is welded, i.e., heat-fused, to an edge section  106  of the upper film sheet  102 . Alternatively, the entire planar base  16  could be welded to the upper film sheet  102 .  
         [0024]    Still referring to FIG. 1, the female profile  14  comprises a planar base  24  and first and second legs  26 ,  28  extending therefrom. Legs  26 ,  28  terminate in inwardly pointing detents  30 ,  32 , for releasably engaging respective detents  22  of enlarged head  20  of the male profile  12 . A plurality of apertures  34  (only one of which is seen in FIG. 1), arranged at spaced intervals along a line that would lie perpendicular to the plane of the drawing sheet in FIG. 1, are formed in the planar base  24 , thereby providing communication from the space  36  formed between legs  26 ,  28  to an opposite side of the planar base  24 . The apertures  34  can have any one of a variety of shapes. The planar base  24  comprises a first extension flange  38  on one side thereof that extends away from the first and second legs  26 ,  28  and has a distal end  40  that is welded to an edge  108  of the lower film sheet  104 . Because the portion of planar base  24  proximate to apertures  34  is not welded to the lower film sheet  104 , this provides communication from space  36  to the interior of bag  100 . Therefore, as shown in FIG. 1, when powder product  200  is lodged within space  36  between legs  26 ,  28  of the female profile  14 , the subsequent insertion of male element into space  36  between legs  26 ,  28  urges powder product  200  through apertures  34  in the planar base  24  and into the interior of the bag  100 .  
         [0025]    As shown in FIG. 1, the planar base  24  of female profile  14  further comprises a second extension flange  46  that extends inwardly into the bag  100 . The distal end  48  of the second extension flange  46  is welded to the proximal end  50  of a deflector sheet  52 . Alternately, deflector  52  and extension flange  46  may be made of one piece and folded at the desired location. The distal end of the deflector sheet  52  abuts the second leg  28  of female profile  14 , thereby tending to deflect powder product away from the female profile  14  as powder product is being dispensed from the bag  100 , thereby decreasing the amount of powder product  200  which lodges in the space  36  between first and second legs  26 ,  28  of the female profile  14 .  
         [0026]    In accordance with this prior art zipper, knobs  44  are formed on the planar base  24  and protrude therefrom adjacent to the apertures  34 , thereby maintaining a space between the planar base  24  and the lower film sheet  104 , and likewise maintaining a communication path between apertures  34  and the interior of the bag  100  in the face of the pressure exerted against the female profile  14  during closure of the zipper.  
         [0027]    Whereas FIG. 1 shows a prior art solution to the problem of powder clogging the female profile of a flexible zipper having an arrow-shaped male element, the present invention is directed to solving a similar problem in cases where a zipper also has two profiles, not just a female profile, that are susceptible to becoming clogged with powder or other particulate matter.  
         [0028]    One type of male profile that is susceptible to powder clogging is seen in FIG. 2. The male profile of the zipper is generally designated by the numeral  54 , while the female profile of the zipper is generally designated by the numeral  56 . In accordance with one embodiment of the invention, the male profile  54  comprises a pair of spaced legs or hooks  58 ,  60  terminating in respective outwardly pointing detents  62 ,  64 , while female profile  56  comprises a pair of spaced legs or hooks  66 ,  68  terminating in inwardly pointing detents  70 ,  72  that respectively releasably engage the detents  62 ,  64  when the male and female profiles are interlocked, i.e., when the zipper is closed, as seen in FIG. 2. In accordance with this embodiment, the hooks  58  and  60  of the male profile are mutually parallel profiled structures that are separated by a space having a first width, while the hooks  66  and  68  of the female profile are mutually parallel profiled structures that are separated by a space having a second width greater than the first width. The first and second widths are selected so that the crowns of the legs  58 ,  60  will lie between the crowns of the legs  66 ,  68  when the male profile first engages the female profile during a closure operation.  
         [0029]    As best seen in FIG. 3, when the male and female profiles are interlocked, a hat-shaped space  74  is defined between the interlocked profiles. In accordance with the embodiment depicted in FIGS. 2 and 3, the space  74  communicates with a plurality of apertures  76  (only one shown in FIG. 3) formed in the male profile  54  and with a plurality of apertures  78  (only one shown in FIGS. 2 and 3) formed in the female profile  56 . The apertures  76  in the male profile are spaced along a line that runs parallel to and between the legs  58 ,  60 , while the apertures  78  in the female profile are spaced along a line that runs parallel to and between the legs  66 ,  68 . Although the apertures are represented in FIGS. 2 and 3 as rectangles, the apertures may have any other shape, such as circular, oval, elliptical, elongated, square, hexagonal, etc. Further, the apertures in either profile may vary in size. Also the apertures formed in the male profile may differ in shape and/or size from the apertures in the female profile.  
         [0030]    Referring to FIG. 3, the male profile  54  comprises a planar base  80  having an extension flange  82  on one side thereof which extends away from the interior volume of the package and has a distal end that is welded to an edge  106  of the upper film sheet  102 . Because the portion of planar base  80  proximate to apertures  76  in the male profile is not welded to the upper film sheet  102 , this provides communication from space  74  to the interior volume of the bag. Similarly, the female profile  56  comprises a planar base  84  having an extension flange  86  on one side thereof which extends away from the interior volume of the package and has a distal end that is welded to an edge  108  of the lower film sheet  104 . Because the portion of planar base  84  proximate to apertures  78  in the female profile is not welded to the lower film sheet  104 , this provides a second communication path from space  74  to the interior volume of the bag. As a result of the foregoing construction, when powder product  200  is lodged within space  74 , the subsequent insertion of legs  58 ,  60  of the male profile into the space between legs  66 ,  68  of the female profile urges powder product  200  through apertures  76  and/or  78  and into the interior volume of the bag. Thus, means are provided for allowing powder to escape from the longitudinal space formed between the interlocked zipper halves into the interior volume of the package or bag. These features resist clogging of either or both of the male and female profiles when the zipper is attached to a package containing powder or other particulate matter.  
         [0031]    In accordance with a second embodiment of the invention depicted in FIG. 4, the male profile  54  has a series of apertures  76 , while the female profile  56 ′ has no apertures. Instead the female profile  56 ′ has a post  88  that fits between the legs  58  and  60  of the male profile  54  and pushes powder out of the apertures  76  in the male profile when the latter is pressed into the female profile  56 ′. Although not visible in FIG. 4, the post  88  preferably has a length greater than the distance separating the apertures in the male profile that are furthest apart. The distal end of post  88  on the female profile  56 ′ preferably has a rounded or contoured convex profile. The contoured post serves as a guide for proper alignment of the incoming legs of the male profile during a zipper closure operation.  
         [0032]    In accordance with another embodiment of the invention depicted in FIGS. 5 and 6, the female profile  56 ″ is provided with a plurality of apertures  78  and a plurality of posts  88 ′ arranged in alternating sequence. The spaced posts  88 ′ are arranged along the same longitudinal line as and alternate with the spaced apertures  78  formed in the female profile. Although not shown in FIGS. 5 and 6, the male profile has the same structure as that shown in FIG. 4, except that the male profile has no apertures  76 . As seen in FIGS. 5 and 6, the distal end of each post  88 ′ on the female profile  56 ″ preferably has a rounded or contoured convex profile. The posts  88 ′ also act as guides for the incoming male profile during a zipper closure operation. Powder trapped between the legs  66 ,  68  of the female profile  56 ″ can be pushed out through the apertures  78  when the male profile is pressed into the female profile. In this case, the apertures are preferably larger in area than the base of an individual post  88 ′.  
         [0033]    A person skilled in the art will appreciate that the invention is not limited to zippers having a male profile with outwardly pointing detents and a female profile with inwardly pointing detents. Instead, one profile may comprise first and second mutually parallel locking members (e.g., having hook-shaped profiles), each of the first and second members having a respective detent pointing in one and the same direction, while the other complementary profile will comprise third and fourth mutually parallel locking members (e.g., having hook-shaped profiles), each of the third and fourth members having a respective detent pointing in the opposite direction. In such embodiments, each profile base could be provided with a row of apertures in the region between its parallel locking members. One example is shown in FIG. 7, wherein one zipper part comprises a series of spaced apertures  76  communicating directly with a space between parallel hooks  92  and  94 , while the other zipper part comprises a series of spaced apertures  78  (only one is seen in FIG. 7) communicating directly with a space between parallel hooks  96  and  98 , which interlock with hooks  92  and  94 .  
         [0034]    [0034]FIG. 8 shows an alternative construction for a female profile of the type depicted in FIG. 1. In accordance with this construction, the material cut to provide each spaced aperture  234  formed in the planar base  224  is not removed. Rather, the material is left attached along an edge  226  providing a flap closure  228  for each aperture  234 . By cutting or punching the apertures from the top down (i.e., from the arms toward the base), the flaps will position to open below the base  224  of the female profile (as shown in FIG. 8) and thereby serve somewhat as a one-way valve to permit powder to flow out of the female profile into the interior volume of the package, while preventing powder from flowing from the interior volume of the package into the space between the legs of the female profile. In place of a single flap, a pair of flaps may be provided, hinged from opposite sides of the aperture. The person skilled in the art will appreciate that such flaps can also serve as one-way valves for the apertures  76  and  78  seen in FIGS.  2 - 7 .  
         [0035]    In addition, the embodiments of the invention depicted in FIGS.  2 - 7  may also be provided with knobs similar to knobs  44  shown in FIG. 1. For example, such knobs could be formed on the outer surface of the planar base  80  of the male profile  54  (see FIG. 3), a respective set of knobs being placed adjacent or near each aperture  76 . These knobs would maintain a space between the planar base  80  of the male profile  54  and the upper film sheet  102  of the bag, and would likewise maintain a communication path between apertures  76  and the interior of the bag in the face of the pressure exerted against the male and female profiles  54  and  56  during closure of the zipper. Knobs would also be formed on the outer surface of the female profile  56  to maintain a communication path between apertures  78  and the interior of the bag.  
         [0036]    While the invention has been described with reference to embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for members thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.  
         [0037]    As used in the claims, the term “package” means a container, bag, pouch or other receptacle for objects, material or stuff. A container, bag, pouch or other receptacle is deemed to be a package even if not yet packed with objects, material or stuff.