Abstract:
Gussetted packages having openable and reclosable interlocking seals, the seals having male and female portions, snap detents, and formed transversely to the direction of film flow. The packaging film is provided at package length intervals with thermoformable strips secured thereto transversely to the running length of the film, and is fed to a modified standard vertical form, fill and seal packaging machine with gussets forming tooling where the film is formed into a bag with the thermoformable strips inside at the upper end of the bag, product deposited into the bag, the bag sealed, the reclosable interlocking seal formed, and the bag severed from the next bag being formed. The reclosable seal provides auditory and tactile indications of seal closing. Some packages are formed with the thermoformable strips in the gusset, and some are formed with the gusset free of strip material.

Description:
This application is a continuation in part of application Ser. No. 09/693,963 filed on Oct. 10, 2000, now U.S. Pat. No. 6,371,644. 
    
    
     This invention relates generally to packaging systems, and more particularly to flexible gussetted packages having an openable and reclosable interlocking seal provided with snap detents spaced along a major part of the length of the seal, the reclosable interlocking seal having male and female parts with the detents being formed in the female part and extending into the male part. The novel seal and snap detents structure provides tactile and auditory snap indications of the state of the seal during opening and closing of the package. Also disclosed are methods and apparatus for making such packages and seals from a continuous web of flexible film, the seals being formed during package formation at line speed. 
     BACKGROUND OF THE INVENTION 
     The advantages of gussetted packages for the storage of some kinds of substances is well known, and particularly where a wide mouth package or pour spout is desired. They also provide superior case packing and display shelf utilization as compared to stand-up pouches which may have zipper closures. The known art directed toward gussetted packages with some form of snap closure is Galomb U.S. Pat. No. 6,082,897. Galomb discloses a bulky two element pre-formed semi-rigid snap structure comprising a male part and a female part both affixed to the outside of the package by tacking or adhesive, each of which parts is secured to the package material along only one of the part edges so that the package material can move longitudinally relatively to the female part and can be stuffed into it by the male part during package closure. The snap parts are sufficiently bulky and rigid that they are not capable of being run over the forming collar of a vertical form fill apparatus and must be separately inventoried and affixed to the package after it has been formed. No apparatus for or method of making the package is disclosed by Galomb. 
     SUMMARY OF THE INVENTION 
     The gussetted package and system according to the present invention utilize composite packaging film structures comprising the packaging film with several different configurations of strips of formable plastic laminated to the film at package length intervals from which several different gussetted packages are respectively formed, some packages having the formable plastic strip within the gussets and some packages which utilize relatively thick packaging film having the gussets formed without such plastic strip. The composite packaging film structures may be preformed and stored as roll stock material, which does not appear to be practical with the Galomb structure, or may be concurrently made with package formation by a Sig Pack, Inc. Easy Snap™ Laminator mounted atop or adjacent to the packaging apparatus to form one of the shown and to be described specific novel composite packaging film structures, which composite film is then fed into the packaging apparatus with the plastic strips disposed on the inside of the package and incorporated into the novel reclosable seal formed in the film and strip composite. The laminator functions with both horizontal and vertical form/fill/seal wrapping machines and with overwrap packagers, and laminates various plastic strip materials to diverse heat seal packaging films to selectively form several related types of gussetted packages. 
     As disclosed in application Ser. No. 09/693,963, the packaging films could be for example, polypropylene, polyethylene, polystyrene, polyvinylchloride, thermoplastic heat seal coated non-plastic films, and various film laminations of two to four layers, while the plastic strip could be formed of one to three layers. In some applications the strip could be a single thickness of polyvinylchloride (PVC) heat sealed to a PVC film at a temperature of about 230° F. for ½ to ¾ seconds, while in-other applications the strip could be of two layers such as PVC plus a sealing layer, or three layers such as a center layer coated on opposite sides respectively with a sealing layer and a release layer to prevent the strip from self adhering during formation of the reclosable interlock seal. A commonly used packaging film is a four layer film consisting of two layers of polypropylene separated by a layer of low density polyethylene and having a heat seal layer of low density polyethylene coated on one face. 
     The invention is shown and described in conjunction with a modified vertical form, fill and seal packaging machine having a novel package sealing press which latter also forms the novel resealable closure, the packaging machine being for example a Sig Pack, Inc. Eagle Infinity, Model 1524 fitted with standard gusset tooling, Gussetted packages made according to the invention incorporating the novel reclosable seal also address consumer complaints relating to prior art zipper seals by providing clear auditory and tactile indications of the closing of the reclosable seal by incorporation of snap detents, so that the consumer is assured that the package has been resealed even in the absence of visual package inspection. 
     Accordingly, it is a primary object of the invention to provide novel gussetted packages with openable and reclosable interlocking seals. 
     Another object of the invention is to provide novel composite packaging film structures comprising packaging film with strips of formable plastic laminated to the film at package length intervals. 
     An additional object of the invention is to provide novel gussetted packages having a novel openable and reclosable interlocking seal as aforesaid in which the bulk of the seal structure is provided by an added layer of strip material secured in a specific way to the packaging film at package length intervals. 
     A further object of the invention is to provide novel gussetted packages having novel openable and reclosable interlocking seals as aforesaid in which the ends of the strip material are positioned in abutment at substantially the center of one face of the package to provide a hinge to assist in package opening. 
     Still another object of the invention is to provide novel gussetted packages having reclosable interlocking package seals having male and female parts with snap detents formed in the parts, the closure structure providing tactile and auditory snap indications of the state of the closure during opening and closing of the package. 
     A yet further object of the invention is to provide novel gussetted packages as aforesaid in which the reclosable interlocking seal is formed from the packaging film and a heat sealable strip heat sealed to the packaging film. 
     A still further object of the invention is to provide novel gussetted packages as aforesaid in which the packages may be formed from a variety of packaging films such as polypropylene, polyethelene, polystyrene, polyvinylchloride, and various film laminates. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects of the invention will be more clearly understood from a reading of the following description in conjunction with an examination of the appended drawings, wherein: 
     FIG. 1 is a diagrammatic side view of the apparatus according to the invention showing the method and stages of gussetted package forming, filling, sealing, and severing; 
     FIG. 2 is a diagrammatic front view of the apparatus seen in FIG. 1; 
     FIG. 2A is,an isometric view of the gusset tooling utilized in the apparatus of FIGS. 1 and 2; 
     FIG. 3 is a plan view of a portion of one form of the composite film showing the packaging film and the placement of the attached plastic strips suitable for making a gussetted package having a fin seal longitudinal seal, and in which the gussets include a portion of the plastic strip material; 
     FIG. 4 is a diagrammatic cross section view through an open top gussetted package formed from the film of FIG. 3 showing the sides gussets which include a portion of the plastic strip material; 
     FIG. 4A is a diagrammatic cross sectional view of the package of FIG. 4 in its closed condition; 
     FIG. 5 is a plan view of a portion of another form of the composite film showing the packaging film and the placement of the attached strip suitable for making a gussetted-package in which both side gussets are free of the plastic strip material and are formed only by the packaging film; 
     FIG. 6 is a diagrammatic cross sectional view through an open gussetted package formed from the film of FIG. 5; 
     FIG. 6A is a diagrammatic cross sectional view of the package of FIG. 6 in its closed condition; 
     FIG. 7 is a plan view of a portion of another form of the composite film showing the packaging film and the placement of an attached plastic strip suitable for making a gussetted package having a fin seal longitudinal seal, a half package transversely extending fixed seal, and a half package transversely extending gussetted reclosable seal; 
     FIG. 8 is a diagrammatic cross section view through an open reclosable seal gussetted package formed from the film of FIG. 7, the package having a fin seal longitudinal seal, a half package transversely extending fixed seal, and a half package transversely extending gussetted reclosable seal in which the gusset include a portion of the plastic strip material; 
     FIG. 8A is a diagrammatic cross sectional view of the package of FIG. 8 in its closed condition; 
     FIG. 9 is a plan view of a portion of yet another form of composite film showing the packaging film and the placement of the attached plastic strips suitable for making a gussetted package having a fin seal longitudinal seal, a half package transversely extending fixed seal, and a half package transversely extending gussetted reclosable seal, and in which the gussets are free of any plastic strip material; 
     FIG. 10 is a diagrammatic cross section view through an open reclosable seal gussetted package formed from the film of FIG. 9; 
     FIG. 10A is a diagrammatic cross sectional view of the package of FIG. 10 in its closed condition; 
     FIG. 11 is an enlarged expanded vertical cross sectional view showing the detailed structure of the gussetting tooling and seals forming and package severing apparatus shown in the phantom circle  11  on FIG. 1; 
     FIGS. 11A through 11C show successive steps in the ends sealing, reclosable seal forming, and package severing process; 
     FIG. 12 is an isometric view showing the forming dies which form the snap detents in the reclosable interlocking seal with a part of the reclosable seal shown in phantom outline; 
     FIG. 13 is an enlarged fragmentary isometric view of the inner and outer parts of the reclosable seal in separated position, showing the snap detents in the sidewalls of the seal adjacent to the arrowhead interlock; 
     FIG. 14 is an enlarged cross section through the reclosable seal shown in the phantom circle on FIG. 11C showing the placement of the forming dies of FIG.  12  and between the snap detents; 
     FIG. 15 is an enlarged cross section through the reclosable seal and the snap detents which are formed between the teeth of the forming dies, as would be seen when viewed along line  15 — 15  on FIG. 12; 
     FIG. 16 is an isometric view of a gussetted package according to the invention of the type shown in FIG. 6 but showing a longitudinally extending overlap package seal uppermost, the package end seals, the integrally formed reclosable seal with the female portion uppermost and the seal detent snaps; 
     FIG. 17 shows the package of FIG. 16 with the top end seal removed and the package opened; 
     FIG. 18 is a showing similar to that of FIG. 17 but for the package of FIG. 10; 
     FIG. 19 is is an enlarged cross sectional diagrammatic showing of the upper end of a package including the novel reclosable interlocking seal according to the invention in its closed condition, and the package top heat seal spaced above the reclosable seal with an intervening length of unsecured package film; and 
     FIG. 20 is an enlarged cross sectional diagrammatic showing of the novel reclosable interlocking seal according to the invention similar to FIG. 19 but with the reclosable seal partly pulled open from the top. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the several figures, like elements are denoted by like reference characters, and to the extent possible the reference characters are consistent with those of application Ser. No. 09/693,963. 
     Considering first the side and front diagrammatic elevational views of FIGS. 1 and 2, there is seen a modified conventional vertical form-fill packaging apparatus designated generally as  20  for formong gussetted packages, and which could be for example a Sig Pack, Inc. Eagle Infinity, Model 1524, comprising a vertical cylindrical fill tube  21  surmounted by a conical feed horn  22  into which the material to be packaged is deposited. Disposed adjacent to the feed horn  22  at an angle of about fifteen degrees above the horizontal and turned downward around the feed horn  22  and fill tube  21  with a slight space therebetween is a fill tube forming collar  23 , the purpose of which, together with the fill tube  21 , is to form a composite web of packaging material  24  being fed over the forming collar  23  into a tube having a longitudinally extending seal  26  formed by the heat seal device  27 . 
     A pair of belt drives  28 , by pulling downward on the tube  25 , pull the web  24  downward off of the supply roll  29  or from the composite web forming apparatus  30  which laminates thermoformable strips  31  to the packaging material  32  to form the composite web of packaging material  24 . The apparatus  30  may be a a Sig Pack, Inc. Easy Snap™ Laminator. The filled descending tube is formed into a gussetted tube  25  by the gusset tooling, designated generally at  50  and described more fully in connection with FIGS. 2 and 2A, the gussetted tube passing through the bottom press  33  where it pauses for formation of the top seal  35 , the reclosable seal  36 , formation of a bottom seal  37  of the next descending package, and severing of the completed package  34  from the above lying tube. The completed package  34  is carried away by the conveyor  38 . 
     The apparatus of FIGS. 1 and 2 departs from conventional vertical form-fill apparatus in several particulars, first, by modifying the orientation of the fill tube forming collar  23  to the surface of the conical feed horn  22  by reorienting the forming collar as shown and described in application Ser. No. 09/693,963, and providing a leading edge tack  44  to the strips  31 , as shown in FIGS. 3,  5 ,  7 , and  9  to be subsequently described. The second difference is the inclusion of the subsequently to be described novel bottom press  33  which forms the novel gussetted reclosable seal, in conjunction with the gussetting tooling  50 . The gusset forming tooling  50  is seen, in FIGS. 1 and 2 positioned with the gusset forming plow  51  positioned above the press  33  and with the gusset maintaining tool  52  positioned below the press  33  so that the shape of the gussetted tube  25  is formed above and maintained throughout and somewhat below the vertical extent of the press  33 , whereby the press acts on the gussettted form of the tube  25 . Details of the gusset forming tooling  50 , including the upper plow  51  and the lower maintainer  52  are best seen in the showing of FIG. 2A which also shows the reciprocating mechanism for retracting and inserting the gusset forming plow  51  and maintainer  52 . 
     Considering now FIGS. 3,  5 ,  7 , and  9 , there are seen the packaging film material  32  and respectively a plurality of different configurations of thermoformable strips  31 ,  131 A and  131 B,  231 , and  331 A and  331 B, secured to the film  32  substantially continuously along the strips trailing edges  39  by heat seals  40 , along the strips ends  41  as at  42 , and by short tacks  43  at the center of the strips leading edges  44  to Insure that the leading edge is against the packaging film as the composite web passes into the space between the feed horn  22  and forming collar  23  to prevent tearing off the strips from the film. The strips are all secured to the film inward from the film side edges to provide the margins  48  for formation of the longitudinal fin seals  26 . Various types of suitable plastic strip material are shown and described in application Ser. No. 09/693,963. 
     FIGS. 3,  5 ,  7 , and  9  show the different configurations of strips on the film  32 , required to form the different gussetted packages of FIGS. 4,  6 ,  8 , and  10  respectively. Strip  31  of FIG. 3 produces the gussetted package of FIG. 4 having the strip  31  extending completely peripherally around the inside of the gussetted tube, in the sides of the package and in the gussets  55 . Strips  131 A and  131 B of FIG. 5 form the gussetted package of FIG. 6 with both gussets free of the plastic strip material and formed only by the packaging film  32 , the gussets being defined by the film regions  53  shown in FIGS. 5,  6 ,  9 , and  10 . Strip  231  of FIG. 7 forms the gussetted package of FIG. 8 having a fin seal longitudinal seal, a half package transversely extending fixed seal  54 , and a half package transversely extending gussetted reclosable seal in which the gusset  55  includes a portion of the plastic strip material  231 . Strips  331 A and  331 B of FIG. 9 form the gussetted package of FIG. 10 having a fin seal longitudinal seal, a half package transversely extending fixed seal  54 ′ like that of  54  in FIG. 8, and a half package transversely extending gussetted reclosable seal in which the gusset is free of the plastic strip material and formed only by the packaging film  32 , the gusset being defined by the film region  53  also shown in FIG.  9 . The package transverse extents of the fixed seals  54  of FIGS. 8,  8 A,  10 , and  10 A relative to the extents of the package reclosable seals has been shown as substantially equal, but other ratios can be chosen as desired. 
     The strips  31  and  131 A are also provided with apertures  49  through the strips which in the completed packages act as a weakened region allowing a hinge fold to occur when the package is opened. Another hinge is provided in the completed packages opposite the first hinge by the substantially abutting apposed ends  41  of the strips  31 ,  131 B,  231 , and  331 A and  331 B as seen in FIGS. 4,  6 ,  8 , and  10 , all of which show a fin seal longitudinal package seal  26  formed by the side margins  48 . An overlap longitudinal seal may be made by other vertical form-fill machines, and such is illustrated in FIG.  13 . 
     Turning now to FIGS. 11 through 11C which illustrate the formation of the package end seals and reclosable seal of the package of FIG. 4, there is seen in FIG. 11 a partly completed gussetted package  34  which has been filled with product  56  while descending, and has stopped at a position where the upper part of the package is within the bottom press  33  just prior to completion by the formation of the top seal and reclosable seal. The package  34  is stopped so that the thermoformable strip  31  is positioned between the reclosable seal forming horizontally reciprocable heated female die  58  and the two part heated male die  57 , with an above-lying length  59  of the tube  25  positioned below the composite heated dies  60  and  61  and the package severing cutter  62  and anvil  63 . The female die  58  is provided with a forming recess  68 , and the male die is provided with a forming wedge  69  carried by the male die part  57 B and shaped complementally to the female die recess  68 . The composite dies  60  and  61  consist of a pair of dies  64  which form the top seal  35  of the package  34  being completed, and a pair of above-lying dies  65  which form the bottom seal  37  of the next package to descend. Disposed above and below the forming recess  68  of female die  58  are a pair of heated reclosable seal detent forming toothed dies  66  reciprocable with the female die  58  and pivotable toward one another on pivots  67 . 
     FIG. 11A shows the reclosable seal forming heated dies  57  and  58  moved toward one another and into engagement, heat forming the package film  32  and thermoformable strip  31  into the recess of the female die  58  to form the point of the arrowhead shaped reclosable seal. For clarity, the strip  31  is not shown in FIGS. 11A through 11C, but its location is seen clearly from FIGS. 11 and 13 to  15 . At the same time, the heated dies  60  and  61  heat seal the gussetted tube  25  entirely widthwise for a vertical interval  70  and define the unsecured interval  59  between the bottom of the top seal  35  and the top of the reclosable seal  36 , the portion of the seal  70  heated by the dies  64  becoming the package top seal  35 , and the portion of the seal  70  heated by the dies  65  becoming the bottom seal  37  of the next descending package when the seal  70  is subsequently severed widthwise by the cutter  62 . 
     The next step is a hybrid-between FIGS. 11A and 11B in which the conditions are as shown in FIG. 11A except that the detent forming dies  66  have pivoted inward and closed sufficiently to begin formation of the inwardly sloping bottom surfaces  72  of the arrowhead shaped interlock, but not sufficiently to clamp the male die forming wedge  69 . 
     FIG. 11B shows the immediately following condition in which the cutter  62  has moved laterally to sever the heat seal  70  against the anvil  63  and separate the package  34  from the above-lying tube  25 . At the same time, male die part  57 B carrying the wedge  69  partially retracts from the recess  68  of female die  58  and from between the teeth  71  of the dies  66 , and the dies  66  pivot further inward driving the detent forming die teeth  71  toward one another to their maximum closed position, the teeth  71  pinching the packaging film  32  and thermoformable strip  31  therebetween to form the film and strip into the female die recess to continue forming the inwardly sloping bottom surfaces  72  of the arrowhead shaped reclosable seal  36 , and forming the snap detents  73  best seen in FIGS. 11 and 13. The female die  58  is then moved somewhat left toward the dies  66  to set the arrowhead shape between itself and the facing surfaces of teeth  71  of detent forming dies  66 . The detents  73  are formed because as the softened thermoformable material of the film and strip are compressed between the teeth  71  the only direction that the compressed material can move is laterally into the spaces between the teeth  71 , and then bulge outward between the teeth, forming the detents  73 . 
     FIG. 11C shows the male and female dies  57  and  58  outwardly retracted with the female die laterally carrying the package  34  held within it by the unopened detent forming dies  66 , and the package end seal dies  60  and  61  and the cutter  62  have been retracted. The dies  66  remain engaged for a short time to complete setting of the detents, after which they open and release the completed package which drops to the conveyor  38  as shown in FIG. 1, and the sequence commencing with FIG. 11 is repeated. Sequencing and timing controls and drives for the sequential movements of the various dies is provided by standard commercially available components. 
     FIGS. 12 through 15 show in greater detail the detent forming toothed dies  66  and the structure of the reclosable seal  36 . FIG. 12 shows more clearly the relationship between the dies and the reclosable seal, and shows the shorter die teeth  76  on one side of the die in the central region of the die corresponding to the region of the overlap longitudinal package seal  26  formed by the film margin  47 , as best shown in FIG. 13, and also for a fin seal as shown in the earlier figures. The dies  66  are also formed at their opposite apposed ends with long flat teeth  80  which are slightly lower than the teeth  71  to accommodate the extra thickness of material in the gussets, the difference in elevation of the teeth  71  and  80  being on the order of thousandths of an inch. In some cases it has also been found desirable to slightly taper the teeth  80  downward from their beginning adjacent to the teeth  71  toward the die ends. 
     FIG. 13 also shows more clearly the snap detents  73  which are formed in the seal male part  36 A and female part  36 B by an outward bulging of the thermoformable material between adjacent teeth  71  of the dies  66  when the dies close. The heat softened material between the apposed die teeth is compressed and can only move laterally, but such movement causes the outward bulging of the material which forms the detents since material is moving from oppsite sides into the same space between the adjacent die teeth and can not move inward. This is also shown in FIG. 14 in which the detents  73  are shown behind the die teeth  71 . FIG. 15 is a section taken through the detents and shows the interfitted arrangement. 
     FIG. 16 shows a completed gussetted package of the type shown in FIG. 6 about to be opened by cutting off the top heat seal  35  with scissors  77 , and FIG. 17 shows the package of FIG. 16 with the top heat seal removed and pulled open, the bag remaining open because of the gussets and hinging folds  78  and  79 . The hinge  78  results from the weakening produced by the strip  31  aperture  49  which is formed into the relatively rigid male part  36 A of the reclosable seal  36 , while the hinge  79  is formed at the abutment of the ends of the strip  31  located in the female part  36 B. The package is simply closed by inward directed finger pressure on the outside of the package along the male and female parts  36 A and  36 B of reclosable seal  36  which causes the package sides to infold the gussets and snap to each other so that the snap detents interlock. FIG. 18 is a showing similar to that of FIG. 17, but for a package of the type shown in FIG. 10, illustrating the pour spout configuration achieved with this form of package. 
     FIGS. 19 and 20 show the upper end of a package  34  in enlarged diagrammatic cross section to illustrate the opening of the package. As shown in FIG. 19, the top seal is removed by cutting below it to provide the free top tabs of packaging film  32  shown in FIG.  20 . These top tabs are pulled away from each other as shown in FIG. 20 to open the female part  36 B of the reclosable seal and disengage it from the inner male part  36 A. The opening leverage is materially increased because the strip  31  is sealed to the film  32  by the trailing edge heat seal  40  and the opening pull is transmitted through the strip  31 . Conversely, inadvertent opening of the package from the body side of the package is discriminated against because the strip  31  is substantially unsecured to the package film  32  at its leading edge  44  inside the package and there is no reinforcement of pull on the film by the strip. 
     Having now described the invention in connection with particularly illustrated embodiments thereof, it will be understood that modifications and variations of the invention may now occur from time to time to those normally skilled in the art without departing from the essential scope or spirit of the invention, and accordingly it is intended to claim the invention both broadly and specifically as indicated in the appended claims.