Abstract:
The present invention relates to an air-tight closure for enhancing accessibility to contents of a container when the container is opened and for preventing exposure of the container contents to ambient air when the container is closed. The invention further relates to re-closable containers including the same. The closure comprises at least two elongated male units disposed a gap apart on the outer surface of one wall of the container and at least two corresponding elongated female units disposed a gap apart on the outer surface of an opposite wall of the container opposite the male units, forming at least two male-female pairs.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to closure means for containers and more specifically to an air-tight snap closure for allowing re-opening and re-closing of a container for keeping the freshness of the container contents. 
   2. Discussion of the Related Art 
   Various off-the-shelf goods, such as food products, are distributed in sealed packages to ensure that the package was not opened before purchasing, to prevent spillage of contents and to prevent exposure of the package contents to ambient atmosphere. For various food products it is also common to seal the package under vacuum, as is well known in the art, for better protecting the products. Once purchased, the initial seal is broken in order to access the package contents. However, many times the contents of the package are not consumed immediately but over a period of time. For this reason, there exist various secondary closure means which allow re-closing and re-opening of a container after the container is first opened and serves both for preventing accidental spillage of the contents and for keeping the freshness of the contents by minimizing the exposure of the container contents to air. Re-closable closures appear in different forms and may be provided either as an integral part of the container or as a separate unit. One family type of such closures comprises two compatible parts deposited on opposite walls of a container which when pressed together form a tight sealing. The two parts may be secured either on the inner or on the outer surfaces of the container walls. In the first case, when closed, the two closure parts are in immediate contact with each other. In the second case, the walls of the container are interposed between the closure members. External closures have some advantages to internal closures. External closure can be attached to a container after it has already been filled and sealed while inner closures can be attached only to empty containers, thus, the step of securing an inner closure must be integrated into the packages production line. Securing an external closure to a package, on the other hand, can be performed at a later stage, hence offering more flexibility. Furthermore, internal closures do not fit for some goods, such as for example powder-like products, which tend to accumulate on the closure surface, hindering the closure operation. 
   Known external closure means, although superior to inner closure, still suffer from a number of drawbacks. One such a drawback is the limit to the separation that can be obtained between the two opposite walls of the container for forming a mouth or an opening sufficiently large to allow convenient access to the container contents This drawback is particularly crucial for bags known in the art as non-gusseted bags, where the two walls of the container are directly connected to each other with no intermediate side walls. Another drawback is the extent of the force that should be applied in order to separate the two parts of the closure. Yet another drawback is that for non-gusseted packages a continuous pressure should be applied to the closure in order to maintain the closure in the open position. 
   Accordingly, it is the object of the present invention to provide an air-tight closure means for containers which can be used with any container and in particular with non-gusseted as well as with gusseted packages and which is easily opened without applying much forces. 
   It is another object to provide such a closure which when opened forms a well defined mouth or an opening that remains open with no need to apply further pressure by the user. 
   It is another object of the invention to provide such a closure that is inexpensive and is easily produced and applied to any container. 
   Other advantages of the invention will be apparent from the following description. 
   SUMMARY OF THE INVENTION 
   The present invention provides an air-tight closure for a container for allowing reclosing of the container after it is initially opened and for enhancing accessibility to the container contents when opened. The invention further relates to re-closable containers including the same. 
   The closure of the present invention can be used with any container having two opposite walls connected to each other and a mouth for providing accessibility to the container contents, wherein the mouth may be initially sealed. In particular, the present closure can be used with a container fabricated from a single layer or multi-layer sheet of a flexible material such as plastic, paper, a metal foil or a combination thereof. The invention further provides reclosable containers including the same. 
   The closure of the invention comprises at least two elongated male units, disposed a gap apart on the outer surface of one wall of the container adjacent to the mouth, such that their longitudinal axes coincide and at least two corresponding female units, disposed a gap apart on the outer surface of the second opposite wall, opposite the male units. The male and female units are configured to snap fit into each other such as to form at least two pairs of male-female pairs. The closure may be disposed along the width of the container or diagonally. The construction of the closure facilitates the opening of the container and enables the closure to remain in its opened position without applying continuous forces. 
   In accordance with one embodiment of the invention the male units comprise two flat elongated wings and an elongated projection interposed there between. The female unit comprises two flat elongated wings and an elongated recess portion interposed there between. The male elongated projection and the female elongated recess portion are having complementary profiles for allowing snap fitting said projection into said recess portion. Preferably, the male units are secured to the outer surface of one wall of the container by adhesive layer or by any other bonding technology, such as heat seal etc., covering at least partly the elongated flat wings. The female units are secured to the outer surface of the other wall of the container by adhesive layer or other bonding technology covering at least partly the elongated recess portion. 
   In accordance with one embodiment of the invention, the male unit and the female unit of each male-female pairs, when manufactured, are connected to each other by two elongated strips interposed there between. The two elongated strips are connected to each other and to the male and female units by thin breakable connections for allowing securing the closure to the mouth of the container strips by folding the closure around the connection between the two elongated strips such that one elongated strip connected to the male unit is disposed on one wall of the container and the second elongated strip connected to the female unit is disposed on the second wall of the container. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which: 
       FIGS. 1A and 1B  illustrate a non-gusseted flexible bag with a closure in accordance with a first embodiment of the present invention in closed and open positions, respectively; 
       FIGS. 1C and 1D  are a cross sectional view along lines C and D of  FIGS. 1A and 1B , respectively; 
       FIGS. 2A and 2B  illustrate a gusseted flexible bag with a re-closable closure in accordance with a second embodiment of the present invention in closed and open positions respectively; 
       FIGS. 2C and 2D  are a cross sectional view along lines C and D of  FIGS. 2A and 2B , respectively; 
       FIGS. 3A–3C  illustrate a flexible bag with a closure in accordance with a third embodiment the present invention;  FIG. 3A  illustrates the bag before initial seal is broken;  FIG. 3B  illustrates the bag in a closed position after the initial seal is broken;  FIG. 3C  illustrates the bag in an open position; 
       FIGS. 4A–4C  illustrate a flexible bag with a closure in accordance with a fourth embodiment the present invention;  FIG. 4A  illustrates the bag before initial seal is broken or removed;  FIG. 4B  illustrates the bag in a closed position after the initial seal is broken or removed;  FIG. 4C  illustrates the bag in an open position; 
       FIGS. 5A–5C  illustrate a flexible bag with a closure in accordance with a fifth embodiment the present invention;  FIG. 5A  illustrates the bag before initial seal is broken;  FIG. 5B  illustrates the bag in a closed position after the initial seal is broken;  FIG. 5C  illustrates the bag in an open position; 
       FIG. 5D  is a cross sectional view of the closure of  FIG. 5A  before the closure is secured to the bag; 
       FIGS. 6A and 6B  illustrate a flexible bag with a re-closable closure in accordance with a sixth embodiment of the present invention in closed and open positions respectively; 
       FIG. 7  illustrates a method for attaching a closure member of the invention to a flexible bag in a perspective and a cross-sectional view, respectively; 
       FIG. 8  illustrates an alternative arrangement for attaching a closure member of the invention to a flexible bag. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings,  FIGS. 1A–1D  show a closure, generally designated  10 , in combination with a flexible bag, generally designated  20 , in accordance with one embodiment of the present invention. The closure enables the bag to be re-closed and reused. The closure comprises two or more separate sections having a gap there between. Bag  20  comprises two opposite walls, a front wall  22  and a rear wall  24  connected at lateral sides  18  and sealed at their bottom and top by seals  34  and  36 , respectively. The bag is preferably made of a single or multi layer sheet material such as plastic film, paper, metalized foil or combination thereof. Bag  20  may be formed from a sleeve or by connecting two sheets  22  and  24  or as more commonly known in the art, from a single folded sheet connected along the folded edges by a fin seal at the rear wall (not shown) to form a tube which is first sealed at the bottom (i.e., seal  34 ) to form a pocket and after the pocket is filled, the remaining top opening (i.e., the package mouth) is sealed by seal  36 . One method to form seal  36  is by heat sealing the two walls directly to one another along transversely sealing lines, as shown in  FIG. 1A , to form a sealing band. The sealing band can be made tearable by perforating or by laser scoring along a line just below the sealing band for facilitating tearing the band. Alternatively, the sealing band can be cut off by scissors. Other methods for sealing a package mouth may involve inclusion of a peelable strip between the inner surfaces of the walls, applying a sealant layer on the inner surfaces along a sealing line which breaks when the two upper edges of opposite walls are pulled apart, etc. It will be realized that any method known in the art for sealing a package may be used in conjunction with the present invention and that the sealing methods are not limited to what is shown. 
   Closure  10  is secured to bag  20  at a predetermined distance below seal  36 , leaving unsealed portions  35  and  33  between seal  36  and the upper edge of closure  10 . Closure  10  comprises a pair of male units  12   a  and  12   b , attached to the external surface of wall  22  and a pair of female units  14   a  and  14   b  (not seen) attached to the external surface of rear wall  24  opposite male units  12 . Male units  12   a  and  12   b  are rigid or semi rigid elongated members spaced apart by a small gap  21 , adjacent to each other along their narrow end. Female units  14   a  and  14   b  are rigid elongated parts spaced apart by a corresponding gap (not seen), located opposite units  12   a  and  12   b , respectively. The gap  21  can be a cut separating between male units  12   a  and  12   b  and between female units  14   a  and  14   b . In an alternative embodiment, gap  21  comprises a gap a millimeter or more separating between male units  12   a  and  12   b  and separating between female units  14   a  and  14   b . Gap  21  can be wider depending on the type of bag  20  and closure  10  material used. Male units  12  and female units  14  are having complementary profiles such that they snap fit into each other. As can be best seen in  FIGS. 1C and 1D , male units  12   a  and  12   b  each comprises two flat elongated wings  11  and a middle elongated rounded projection  13  positioned there between. Male units  12  are attached to the external surface of wall  22  by adhesive layer generally designated  19 , covering partly the inner surface of wings  11 . Alternatively, units  12  may be secured to wall  22  by any other bonding or attaching technique, such as heat sealing, pressure sealing, sewing, pins attaching the respective faces, stapling and any other form of attaching. As can be seen, contact area  19  need not to cover the whole surface of wings  11 , but can cover only the portions proximate to projection  13 . Female units  14   a  and  14   b  comprise a middle rounded recess portion  15  having an outer surface  15   a  and an inner surface  15   b  positioned between two flat wings  16 . Female units  14   a  and  14   b  are attached to the external surface of wall  24  by adhesive layer  19 , or any other bonding technology, covering the inner surface  15   b  of rounded recess portion  15 . When closure  10  is secured to bag  20 , units  12  and  14  are pressed against walls  22  and  24  such that walls  22  and  24  are folded to conform with the inner surface of units  12  and  14 , respectively. 
     FIGS. 1A and 1B  depict bag  20  in a closed and an open positions, respectively. Preferably, closure  10  is provided with bag  20  while the closure is in its closed position. In order to access the contents of bag  20 , seal  36  is first broken or removed, then by pulling rims  33  and  35  outwardly, closure  10  is opened to form a wide open diamond shape mouth  40 . It would be appreciated that although in the embodiment shown here, seal  36  is cut off, bag  20  may be provided with a any seal as described above. One such alternative exemplary seal is a piece of adhesive plastic or paper connecting rims  33 ,  35  placed along side rims  35 ,  36  or across said rims. Thus, when the seal is of the type that is opened by pulling apart the two opposite walls of the container, with no need to cut the seal, the closure of the invention may be secured to the container right below the seal with no need to leave rims between the seal and the closure. 
   Due to the construction of closure  10 , mouth  40  remains in the opened position with no need for applying further forces. Mouth  40  provides a very convenient access to the contents of bag  20 . Thus, the contents of the bag can be accessed either by inserting a scooping device, e.g., a spoon or fingers, through the mouth or by pouring the contents by tilting the bag. It will be appreciated that the rigid angled corner of mouth  40  facilitates pouring the bag contents in a directed manner without accidental spillage in the surrounding. It will be also appreciated that for a non-gusset bag, as bag  20 , a wide-open mouth or opening which remains in an open position without applying further forces or pressure cannot be obtained with only one pair of male-female members. In order to re-close the bag, units  12  are pressed against units  14  for obtaining an air-tight closing. In the embodiment shown here, female units  14  are having some degree of elasticity in the vertical direction, i.e. in the direction of wings  16 , for allowing rounded recess  15  to enlarge upon insertion of projection  13  and to apply pressure on projection  13  for forming tight contact between walls  2  and  24 . 
   Closure  10  may be fabricated from any rigid or semi rigid material. For example, the closure may be fabricated from plastic materials such as polyethylene, polypropylene and the like by extrusion, by injection molding or by any other methods known in the art. Alternatively, the closure may be fabricated from alloy metal and other types of metal such as aluminum. 
     FIG. 2  depict a second embodiment of a closure of the present invention, designated  50 , in a combination with a gusseted package  60 . Package  60  comprises two opposite walls  62  and  64 , a flat bottom  63  and two side walls  65  folded inwardly along lines  67  to form gussets. Package  60  is preferably fabricated from a one layer or multi-layer flexible sheet folded and is sealed along folded edges to form a gusseted package in accordance with any method known in the art. Package  60  is sealed at its upper portion by seal  66  in a similar manner as explained in association with  FIG. 1 . 
   Closure  50  is secured to package  60  below seal  66  separating the interior of package  60  from its upper sealed portion. Closure  50  comprises a pair of male units  52   a  and  52   b  (not seen) disposed on wall  64  and a pair of female units  54   a  and  54   b  disposed on wall  62 . Units  52   a  and  52   b  as well as units  54   a  and  54   b  are spaced apart by gap  71 . After seal  66  is broken, closure  50  can be easily opened by pulling rims  73  and  75  apart to form mouth  70  as can be seen in  FIG. 2B . Gaps  71 , being weak points along the longitudinal axes of closure  50 , serve as hinges for facilitating the opening of the closure without applying much force. The gaps  71  can be a cut separating between male units  52   a  and  52   b  and between female units  54   a  and  54   b . In an alternative embodiment, gaps  71  comprise a gap a millimeter or more separating between male units  52   a  and  52   b  and separating between female units  54   a  and  54   b . Gap  71  can be wider depending on the type of package  60  and closure  50  material used. The profiles of male members  52  and female  54  are best seen in  FIGS. 2C and 2B . As is seen, female units  54 , comprising two flat wings  56  and a rounded recess  55  positioned there between, are having a similar shape as female units  14  of  FIG. 1 . In accordance with the embodiment shown here, male units  52  are also having a similar profile, comprising a rounded unfilled projection  53  positioned between two wings  51 , such that unlike male units  12  of  FIG. 1 , male units  52  are having a substantially uniform cross sectional thickness. In fact, male units  52  and female units  54  may be almost identical units, wherein the internal diameter of recess  55  is slightly larger than the external diameter of projection  53 . The flexibility in the vertical axis, as explained above in conjunction with female members  14  of  FIG. 1 , allows for the insertion of members  52  into members  54 . 
   It will be appreciated by persons skilled in the art that the male-female profiles of the closure of the invention may assume other shapes as well, and are not limited to what is shown here, as long as they have complementary profiles for providing tight contact between the male-female pair and the package walls interposed there between, when the closure is in the closed position. 
     FIG. 3  depict yet another embodiment of a gusseted package, designated  90 , with a closure of the invention, designated  100 . Closure  100  comprises two male elongate units  102   a  and  102   b  and two female units  104   a  and  104   b  of a shape similar to male units  12  and female units  14  of  FIG. 1 , respectively. Package  90  comprises two opposite walls  92  and  94 , a flat bottom  93  and two side walls  95  folded inwardly along lines  97 . Package  90  is sealed at its upper portion by seal  96  comprising two portions of different widths,  96   a  and  96   b , such that seal portion  96   a  ends just above closure  100  or extends further downwardly and ends lower than the to edge of closure  100 , while portion  96   b  ends a distance above closure  100 , leaving an unsealed band  98  above the closure. The proportions of portions  96   a  and  96   b  and closure parts  102   a ,  102   b  can vary and are not limited by what is shown in  FIGS. 3A ,  3 B,  3 C. In an alternative embodiment of the present invention, portion  96   a  can be shorter and portion  96   b  can be longer than is shown and respective closure parts  102   a ,  102   b ,  104   a  and  104   b  can be in respective sizes to fit portions  96   a ,  96   b . Package  90  is further provided with a vertical line seal  99  separating between portions  96   a  and  96   b . Vertical seal  99  extends from top to substantially the lower end of closure  100 . The lengths of male-female pair  102 – 104   a  and pair  102 – 104   b  match the lengths of seal portion  96   a  and  96   b , respectively. In order to access the contents of package  90 , the upper portion of the package is cut off or removed above closure  100  to leave an unsealed portion above closure pair  102 – 104   a , as shown in  FIG. 3B , such that only pair  102 – 104   a  can be opened to form mouth  80 , as shown in  FIG. 3C . Thus, in accordance with this embodiment, the main role of male-female pair  102 – 104   b  is to provide a barrier against erroneous cutting of the package. For example, if only pair  102 – 104   a  was provided, package  90  might have been cut wrongly at the right side of the package, rendering closure  100  useless. 
   Turning now to  FIG. 4 , there is shown another embodiment of the present invention according to which closure  112  is disposed diagonally on bag  122 , extending between seal strap  126  and a lower point along the side edge of package  120  as shown in  FIG. 4A . Closure  110  comprises two elongate male units  112   a  and  112   b  disposed on wall  122  and two female members disposed on the opposite wall (not seen). In order to access the contents of package  120 , the left corner of the package is cut off or removed diagonally above closure  112  as shown in  FIG. 4B  and closure  110  is then opened to form mouth  130 . The portion removed diagonally may be removed prior to or after the sale of package  120 . The closure  110  can be added when the package is manufactured or by the user of package  120  after purchase. 
     FIG. 5  illustrate yet another embodiment of a closure of the invention, generally designated  150 , secured to a package  160 . Package  160 , which only its upper part is illustrated here, can be of any type as previously described, including non-gusseted as well as gusseted packages. Closure  150  comprises two elongate pairs of male-female units,  152 – 154   a  and  152 – 154   b  (shown partly). In accordance with this embodiment each pair of male and female units are connected by two elongated strips  155  which are disposed one opposite the other on the upper top of package  160  as is seen in  FIG. 5A .  FIG. 5D  depicts the profile of male-female pair  150  before it is attached to a package. As is seen, the two strips  155  are located between male unit  152  and female unit  154  are connected to each other as well as to the corresponding male-female members by very thin breakable connections  158  and  156 , respectively. Thin connection  158 , being a hinge around which the closure can be easily folded, allows for folding the closure and attaching it to the package from above such that one half of the closure including male member  152  is pressed against front wall  162  while the other half, including female member,  154  is pressed against rear wall  164 . The profiles of male unit  152  and female unit  154  are having a similar shape as described above in association with  FIG. 1 , having a rounded projection  153  and a rounded recess  157 , respectively. Closure  150  is preferably secured to a sealed package such that strips  155  conceal the seal strap. In order to open the package, connections  158  between strips  155  and members  152  and  154  are broken easily by folding the upper portion of the closure, i.e., strips  155  around thin connections  158 . The package is then cut between the upper and lower portions of closure  150  as shown in  FIG. 5B . Alternatively, connections  158  which are sufficiently thin, need not be cut prior to cutting and can be cut while cutting the package. Closure  170  can then be opened to form a diamond shape mouth  170  having the advantages as described above in association with  FIG. 1 . In accordance with this embodiment, since no rims are left above closure  150 , the closure is adhered or bonded to the container also along the upper wings of the male and female units, as well as along strips  155 , as illustrated in  FIG. 5D , such that the container can be opened by pulling the upper portions of the closure apart. In order to facilitate grasping, upper wings may be made thinner than the lower and middle portions of the closure as is best seen in  FIG. 5D . 
   It will be appreciated by that the closure of the invention may be made in various sizes and strengths wherein the closure strength is generally determined by the material from which it is fabricated and from its cross-sectional thickness. Generally, the closure dimensions depend on the container dimensions and in particular on the thickness and flexibility of the container walls. Preferably the total width of the closure is in the range of about 3 to 20 mm or more and the units thickness across the wing portion is in the range of about 0.25 to 2 mm or more. Likewise, the number of male-female pairs disposed on the container walls for separating the interior of the container from the container mouth may be selected to best fit the dimensions of the container mouth. Thus, for large containers, the closure of the invention may comprise any number of mail-female pairs disposed adjacent to the package mouth.  FIG. 6  illustrate a closure of the invention, designated  180  secured to bag  190 . Closure  180  comprises three male units  182   a ,  182   b  and  182   c  disposing a gap apart on front wall  192  of package  190  and three complementary female units  184   a ,  184   b  and  184   c  disposing a gap apart on opposite rear wall  194 . After seal  196  is broken, closure  180  can be opened to form hexagonal mouth  170 . It will be appreciated that regardless the number of male-female pairs, the gaps between adjacent members always serve as hinges for facilitating the separation of the closure. 
     FIG. 7  illustrate an automated process for attaching the closure of the invention to packages. According to this process, a rolled ribbon  202  of a pair of male units  212  and a rolled ribbon  204  of pair of female units  214  are moved on mover mechanisms  216  and  218 , respectively. Each ribbon comprises of a plurality of elongated unit pairs arranged along their elongated axis by thin breakable connections. The two units of a pair as well as one pair to adjacent pairs can be connected to each by thin breakable connections which break upon slight pressure as is well known in the manufacturing of plastic units. Alternatively, the units can be detachably placed on a support of a sheet material. Mover mechanisms  216  and  218 , each provided with lugs and latches (not shown), push the upper units in the roller unwinding direction and the most upper unit, each in its turn, away from the roller in the perpendicular direction, toward packages  220  moving on a convey (not seen), or packaging machine or any bag making machine, such that units  212  is and  214  are located each on one side of package  220  against each other. Turning now to  FIG. 7B , two pressers  252  and  254  provided with moving pressing heads  253  and  255  respectively, press units  212  and  214  onto the upper part of package  220  and interlock them into each other. In the embodiment shown here each, rollers  202  and  204  comprise of unit pairs. However it will be appreciated that instead of using two rollers, each comprising of unit pairs, two separate rollers of male members and two separate rollers of female members can be used such that two pair of male-female members are directed toward the package and toward each other from opposite directions by four separate synchronized mover mechanisms. 
     FIG. 8  illustrates another embodiment for automatic securing the closure of the invention to packages  320 , according to which the closure units  312  are arranged along their narrow side. For clarity sake, only one roller  304  of female units  312  is shown. However it will be understood that a second roller of male units, as well as a second presser, are provided on the other side of package  320 , pressing male units against the female units as described above. It will be realized that arranging the male and female units in a roller such as  304 , i.e., where the units are connected to each other along their narrow end, is possible due to the novel construction of the closure of the invention, which comprises separate male-female pairs. Thus, a long ribbon of such units can be rolled to in a roller of a reasonable diameter while it is not practical to form such a roller where the length of the units equals the container width. 
   It will be easily appreciated by a person skilled in the art that the use of the present closure is not limited to the packages described above and that it can be attached to many other packages as well for providing an air tight closing. Likewise it will be realized that the closure of the present invention may be attached to unsealed empty containers as well. For example, empty packages with the present closure can be useful where goods are sold to customers by weight. In such cases, the distributor of the goods can pack the goods in empty bags provided with the closure of the present invention such that the closure is the only sealing means provided with the container. 
   It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention is defined only by the claims which follow.