Bandolier format packaging

This application is a divisional of U.S. application Ser. No. 11/103,770, entitled “Bandolier Format Packaging” and filed on Apr. 12. 2005, now pending, which application is itself a continuation-in-part of U.S. application Ser. No. 10/721,953. entitled “Double-Bag Package and Perforation Knife” and filed on Nov. 25, 2003. now U.S. Pat. No. 6,935,086, which application is itself a continuation-in-part of U.S. application Ser. No. 10/100,370, entitled “Vertical Stand-Up Pouch” and filed on Mar. 18, 2002, now U.S. Pat. No. 6,722,106.

1. Technical Field

The present invention relates to a double-bag package constructed using a modified vertical form and fill packaging machine and a modified perforation knife, and the method for making same, that provides for a single piece construction of a package having two horizontally adjacent bags joined together by a perforated vertical seal having self-correcting directional perforations. The package is suitable for retail snack food distribution. The invention allows for use of existing film converter and packaging technology to produce a double-bag package with minimal increased costs and minimal modification. Further, this invention relates to creating a string of connected individual packages separated by perforations between each package. A string of packages can thus be further packaged, labeled, handled, shipped, sold, and used.

2. Description of Related Art

Vertical form, fill and seal packaging machines are commonly used in the snack food industry for forming, filling and sealing bags of chips and other like products. Such packaging machines take a packaging film from a sheet roll and form the film into a vertical tube around a product delivery cylinder. The vertical tube is vertically sealed along its length to form a back seal. The machine applies a pair of heat-sealing jaws or facings against the tube to form a transverse seal. This transverse seal acts as the top seal on the bag below and the bottom seal on the package being filled and formed above. The product to be packaged, such as potato chips, is dropped through the product delivery cylinder, into the formed tube, and is held within the tube above the bottom transverse seal. After the package has been filled, the film tube is pushed downward to draw out another package length. A transverse seal is formed above the product, thus sealing it within the film tube and forming a package of product. The package below said transverse seal is separated from the rest of the film tube by cutting across the sealed area.

One such packaging machine is seen diagrammatically in FIG. 9. This drawing is simplified, and does not show the cabinet and support structures that typically surround such a machine, but it demonstrates the working of the machine well. Packaging film 910 is taken from a roll 912 of film and passed through tensioners 914 that keep it taut. The film then passes over a former 916, which directs the film into a vertical tube around a product delivery cylinder 918. As the lube is pulled downward by drive belts 920, the vertical tube of film is sealed along its length by a vertical sealer 922, forming a back seal 924. The machine then applies a pair of heat-sealing jaws 926 against the tube to form a transverse seal 928. This transverse seal 928 acts as the top seal on the bag 930 below the sealing jaws 926 and the bottom seal on the bag 932 being filled and formed above the jaws 926. After the transverse seal 928 has been formed, a cut is made across the sealed area to separate the finished bag 930 below the seal 928 from the partially completed bag 932 above the seal. The film tube is then pushed downward to draw out another package length. Before the sealing jaws form each transverse seal, the product to be packaged is dropped through the product delivery cylinder 918 and is held within the tube above the transverse seal 928.

The material that is fed into the form, fill and seal machine is typically a packaging film, such as polypropylene, polyester, paper, polyolefin extrusions, adhesive laminates, and other such materials, or from layered combinations of the above. For many food products, where flavor retention is important, a metalized layer will form the innermost layer.

The form, fill and seal machines are quite expensive., in the range of $250,000 each, but pay for themselves easily when compared to the cost of pre-formed bags and the machinery to fill them. However, in order to maximize the productivity of the form, fill and seal machines, it is common for the product delivery tube 918 and former 916 to be made as a unit that is easily interchangeable in less than 15 minutes. The length of the transverse seal can also be changed, by exchanging the sealing jaws, or in some cases, merely by exchanging the facing (the portion of the sealing jaws which actually makes contact with the packaging film). By changing these elements, as well as the width of film roll feeding into the machine and the programming of the machine, one form, fill and seal machine can handle a number of different products in different size packages, limited primarily by the width of film the machine will handle, the maximum length of bag the machine is designed to handle, and the available former/delivery tube assemblies.

The packaging film used in such process is typically a composite polymer material produced by a film converter. For example, one prior art composite film used for packaging potato chips and like products is illustrated in FIG. 1, which is a schematic of a cross-section of the film illustrating each individual substantive layer. FIG. 1 shows a sealable inside, or product side, layer 16 which typically comprises metalized oriented polypropylene (“OPP”) or metalized polyethylene terephtalate (“PET”). This is followed by a laminate layer 14, typically a polyethylene extrusion, and an ink or graphics layer 12. The ink layer 12 is typically used for the presentation of graphics that can be viewed through a transparent outside layer 10, which layer 10 is typically OPP or PET.

The prior art film composition shown in FIG. 1 is ideally suited for use on vertical form and fill machines for the packaging of food products. The metalized inside layer 16, which is usually metalized with a thin layer of aluminum, provides excellent barrier properties. The use of OPP or PET for the outside layer 10 and the inside layer 16 further makes it possible to heat seal any surface of the film to any other surface in forming either the transverse seals or back seal of a package.

Typical back seals formed using the film composition shown in FIG. 1 are illustrated in FIGS. 2a and 2b. FIG. 2a is a schematic of a “lap seal” embodiment of a back seal being formed on a tube of film. FIG. 2b illustrates a “fin seal” embodiment of a back seal being formed on a tube of film.

With reference to FIG. 2a, a portion of the inside metalized layer 26 is mated with a portion of the outside layer 20 in the area indicated by the arrows to form a lap seal. The seal in this area is accomplished by applying heat and pressure to the film in such area. The lap seal design shown in FIG. 2a insures that the product to be placed inside the formed package will be protected from the ink layer by the metalized inside layer 26.

The fin seal variation shown in FIG. 2b also provides that the product to be placed in the formed package will be protected from the ink layer by the metalized inside layer 26. Again, the outside layer 20 does not contact any product. In the embodiment shown in FIG. 2b, however, the inside layer 26 is folded over and then sealed on itself in the area indicated by the arrows. Again, this seal is accomplished by the application of heat and pressure to the film in the area illustrated.

Regardless of whether a lap seal or fin seal is used for constructing a standard package using a vertical form and fill packaging machine, the end result is a package as shown in FIG. 3a with horizontally oriented top and bottom transverse seals 31, 33. Such package is referred to in the art as a “vertical flex bag” or “pillow pouch,” and is commonly used for packaging snack foods such as potato chips, tortilla chips, and other various sheeted and extruded products. The back seal discussed with reference to FIGS. 2a and 2b runs vertically along the bag and is typically centered on the back of the package shown in FIG. 3a, thus not visible in FIG. 3a. Because of the narrow, single edge base on the package shown in FIG. 3a formed by the bottom transverse seal 33, such prior art packages are not particularly stable when standing on one end. This shortcoming has been addressed in the packaging industry by the development of a horizontal stand-up pouch such as the embodiment illustrated in FIGS. 4a, 4b, and 4c. As can be seen by reference to said figures, such horizontal stand-up pouch has a relatively broad and flat base 47 having two contact edges. This allows for the pouch to rest on this base 47 in a vertical presentation. Manufacture of such horizontal stand-up pouches, however, does not involve the use of standard vertical form, fill, and seal machines but, rather, involves an expensive and relatively slow 3-piece construction using a pouch form, fill, and seal machine.

Referring to FIGS. 4b and 4c, the horizontal stand-up pouch of the prior art is constructed of three separate pieces of film that are mated together, namely, a front sheet 41, a rear sheet 43, and a base sheet 45. The front sheet 41 and rear sheet 43 are sealed against each other around their edges, typically by heat sealing. The base sheet 45 is, however, first secured along its outer edges to the outer edges of the bottom of the front sheet 41 and rear sheet 43, as is best illustrated in FIG. 4c. Likewise, the mating of the base sheet 45 to the front sheet 41 and the rear sheet 43 is also accomplished typically by a heat seal. The requirement that such horizontal stand-up pouch be constructed of three pieces results in a package that is significantly more expensive to construct than a standard form and fill vertical flex bag.

Further disadvantages of using horizontal stand-up pouches include the initial capital expense of the horizontal stand-up pouch machines, the additional gas flush volume required during packaging as compared to a vertical flex bag, increased down time to change the bag size, slower bag forming speed, and a decreased bag size range. For example, a Polaris model vertical form, fill, and seal machine manufactured by Klick Lock Woodman of Georgia, USA, with a volume capacity of 60-100 bags per minute costs in the range of $75,000.00 per machine. A typical horizontal stand-up pouch manufacturing machine manufactured by Roberts Packaging of Battle Creek, Mich., with a bag capacity of 40-60 bags per minute typically costs $500,000.00. The film cost for a standard vertical form, fill, and seal package is approximately $0.04 per bag with a comparable horizontal stand-up pouch costing roughly twice as much. Horizontal stand-up pouches further require more than twice the oxygen or nitrogen gas flush. Changing the bag size on a horizontal stand-up pouch further takes in excess of two hours, typically, while a vertical form and fill machine bag size can be changed in a matter of minutes. Also, the typical bag size range on a horizontal stand-up pouch machine is from 4 oz. to 10 oz., while a vertical form and fill machine can typically make bags in the size range of 1 oz. to 24 oz.