Abstract:
A horizontal bag-making machine having a packaging material delivery unit, a product delivery unit, and a folding, sealing, and separating unit for folding the packaging material into a tube, sealing the folded packaging material in the directions transverse and parallel to a conveying direction and for cutting the packaging material into individual bag packages also has a tear-open assistance unit located in the conveying direction between the product delivery unit and the folding, sealing, and separating unit. The tear-open assistance unit produces an overlap of material in the separation region, the overlap of material extending at least approximately transversely to the conveying direction of the packaging material, and releasably fixes the overlap of material in the separation region. The bag packages produced in this way are easy to open yet are still in accordance with stringent hygiene regulations.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 35 USC 371 application of PCT/DE 2005/000585 filed on Apr. 1, 2005. 
     BACKGROUND OF THE INVENTION 
     1. Prior-Art Field of the Invention 
     The invention relates to an improved packaging machine for producing bag packages, to a bag package, and to an improved method for producing a bag package; 
     2. Description of the Prior Art 
     U.S. Pat. No. 5,411,202 discloses a package with two transverse sealing seams and one longitudinal sealing seam extending perpendicular to them. The package has a tear strip, which is applied to the packaging material parallel to the two transverse sealing seams. To assure that the package will in fact tear at the tear strip, it is provided with tear notches in the region of the protruding tab of the longitudinal seal. 
     German Patent Disclosure DE-A 44 26 760 discloses a package with a tear thread that extends parallel to the transverse sealing seams and adheres firmly to the packaging material. The tear thread that must be additionally attached makes production more difficult and thus increases the production costs. If the packaging material is furthermore relatively thick, it is often not possible to tear open the package at this point. 
     U.S. Pat. No. 4,589,553 describes a package for food products of elongated shape, which is provided on one short end with a holder in which a transverse seal and a region of the package adjacent to it are held. Just above the holder, the package is provided with an encompassing perforation strip that extends parallel to the transverse sealing seam. If the holder is held in one hand and if the diametrically opposite transverse seal is pulled, the package tears at the transverse sealing seam, and the food product can be held like a popsicle on a stick and eaten. 
     German Utility Model DE-A 202 12 252 U shows a flat bag package with a longitudinal sealing seam and with transverse sealing seams extending parallel to it; the longitudinal sealing seam is embodied as a tearing aid. 
     German Patent Disclosure DE-A 43 11 841 describes an envelope for notices, with an opening line that extends approximately through its middle. The opening line is embodied in zigzag form. 
     These packages with rated breaking points have the disadvantage that they often fail to meet the stringent regulations for hygiene in the food field, so that the package must be additionally encased in a further protective film. This increases the packaging costs and produces more waste than would be necessary. 
     European Patent Disclosure EP-A 0 785 900 discloses an apparatus for folding accordion folded information sheets. 
     European Patent Disclosure EP-A 0 202 115 also shows a folded apparatus for producing products that are folded crosswise at least twice. 
     SUMMARY AND ADVANTAGES OF THE INVENTION 
     It is therefore an object of the invention to create a packaging machine and a method for producing bag packages that permit simple production of bag packages with a tearing aid. A further object of the invention is to create a bag package that is easy to open. 
     These objects are attained by a packaging machine, a bag package, and a method of producing a bag package which meets stringent hygiene requirements. It is also suitable for packaging different products and can be securely opened. The opening mechanism is simple and easy for the user to understand, even if different products or goods are contained or if the package is made from different materials. 
     One advantage of the package or bag according to the invention is that the product is not touched at any time during the opening process. The process of tearing the package open can also be done in a controlled way, and the package tears apart into two defined parts. 
     In packages that now have to be newly provided with this kind of tearing aid, the label need not be changed, since the package surface remains the same, and the existing pressure units of the packaging machine can be operated with the existing operating parameters. 
     It is also advantageous that the known packaging materials can be used, and no additional material with different properties, such as a stable tear strip, has to be used. 
     A further advantage is that known packaging systems can easily be retrofitted in order to provide the packages with the tearing aid according to the invention. Only one additional unit is necessary, which is preferably located between the delivery unit for the packaging material and its folding and sealing unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention are described in further detail below, in conjunction with the drawings, in which: 
         FIG. 1  is a basic sketch of a package according to the invention, in a first exemplary embodiment; 
         FIG. 2 , a basic sketch of a package according to the invention, in a second exemplary embodiment; 
         FIG. 3 , a basic sketch of a package according to the invention, in a third exemplary embodiment; 
         FIG. 4 , a basic sketch of a package according to the invention, in a fourth exemplary embodiment; 
         FIG. 5 , a basic sketch of a package according to the invention, in a fifth exemplary embodiment; 
         FIG. 6 , a basic sketch of a package according to the invention, in a sixth exemplary embodiment; 
         FIG. 7 , a basic sketch of a package according to the invention, in a seventh exemplary embodiment; 
         FIG. 8  is a basic sketch of a packaging machine having an integrated tear-open assistance unit according to the invention; 
         FIG. 9   a , a detail of the tear-open assistance unit of  FIG. 8 , in a first variant in a first method step; 
         FIG. 9   b , the detail of  FIG. 9   a  in a second method step; 
         FIG. 10   a , a detail of the tear-open assistance unit of  FIG. 8 , in a second variant in a first method step; 
         FIG. 10   b , the detail of  FIG. 10   a  in a second method step; 
         FIGS. 11   a  through  11   f , a detail of the tear-open assistance unit of  FIG. 8  in six steps in a third variant; 
         FIG. 12 , a detail of the tear-open assistance unit of  FIG. 8  in a fourth variant; 
         FIG. 13 , a basic sketch of a packaging machine in a second embodiment; and 
         FIGS. 14   a  through  14   c , a detail of the integrated tear-open assistance unit of the invention in  FIG. 13 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a first exemplary embodiment of the package  1  of the invention. The package  1  is a bag package, of the kind that can be produced in particular by a horizontal bag-making machine and serves to package perishable goods, especially foods, such as chocolate bars or cereal bars. 
     The packaging material of the package  1  typically comprises a one- or multi-layer foil material. However, still other flexible materials can be used as the packaging material. The package  1  has two transverse or end sealing seams  2 , extending approximately parallel to one another, and one longitudinal sealing seam, not visible in  FIG. 1 , extending transversely to the end seams over the entire length of the package  1 . These seals are of a permanent kind; that is, typically they can no longer be undone. Instead, the material tears in the immediate vicinity of the seal, or breaks apart into its individual layers. 
     According to the invention, the package  1  is provided with an encompassing tearing aid  3 , which is formed by an overlapping region  30  of the packaging material. The tearing aid  3  or overlapping region  30  extends at least approximately and preferably precisely parallel to the transverse sealing seams  2 . In this example, it is formed by a singly folded internal packaging material fold  31 , which is connected to an external packaging material edge region  32 . The connection can be separated or undone under tensile stress. The connection is preferably an encompassing, undoable sealing seam  33 . 
     The packaging material fold  31  can change over, by way of a perforation line  38 , into the external packaging material edge region  32 , as is shown in  FIG. 7 . However, as can be seen in  FIG. 1 , the two regions may also not be joined together except at their separable or undoable sealing seam  33 , so that the edge region  32  then has a first edge  35  and the internal packaging material fold  31  has a second edge  36 . These two edges  35 ,  36  rest on one another and are preferably aligned with one another. 
     In the exemplary embodiment of  FIG. 2 , the overlapping region  30  is formed by an encompassing folded strip  37 . The packaging material has a separation line  4 , extending parallel to the transverse sealing seams  2  and extending all the way around the package, which divides the packaging material into a first package region  10  and a second package region  11 , which are completely separated from one another via the separation line  4 . This separation line or gap  4  is now covered over its entire length by the strip  37 . The strip  37  is folded on at least one side. It is furthermore joined detachably, along both long edges, to the first and second package regions  10  and  11 , preferably by means of an separable sealing seam  33 . This seam can also be undone under tensile stress, for instance by grasping the package  1  at the two transverse sealing seams  2  and pulling the package apart. 
     The package in  FIG. 3  differs from that in  FIG. 2  in that the strip  37  is applied not to the outside but to the inside of the package  1 . Thanks to the folding of the strip, despite the separation line  4  being located on the outside, a hygienically sufficiently tight closure of the package is assured. 
     In the variant in  FIG. 4 , the first and second package regions  10 ,  11  are embodied in overlapping fashion. In their overlapping region  30 , there is a folded strip  37 . This strip  37  can be made by suitably folding and cutting the length of packaging material. However, it can also be introduced as a separate part between these two regions  10 ,  11 . Once again, the strip or band  37  is connected to the first and second package regions  10 ,  11  by an undoable connection, and in particular two releasable seals  33  each extending around the circumference of the package  1 . 
     The embodiment shown in  FIG. 5  is again like that of  FIG. 2 , but here the strip  37  is not folded but instead placed as a single layer over the gap or separation line  4  of the two package regions  10 ,  11  and joined releasably to them. Once again, releasable sealing seams  33  extending all the way around the circumference of the package  1  and extending to the right and left of the separation line  4  are preferred. However, one of the sealing seams  33  is embodied as weaker than the other, so that the separation occurs intentionally at that point. It is also possible to design only one of the two sealing seams  33  as undoable and to embody the other as a permanent sealing seam. 
     In the embodiment of  FIG. 6 , the two package regions  10 ,  11  overlap one another, as has already been shown in  FIG. 4 . Here, however, there is no intermediate strip; instead, the two edges of the regions  10 ,  11  are joined directly to one another, for instance via an undoable sealing seam  33  extending all the way around, or by an adhesive bond. 
     In  FIG. 8 , a preferred apparatus for producing such bag packages is shown. This is a known kind of packaging machine for making bag packages, in particular a horizontal bag package making machine, which for forming the tearing aid is provided with a tear-open assistance unit  5  of the invention. 
     The apparatus furthermore has one delivery unit  6  for the packaging material F and one delivery unit  7  for the separate or grouped delivery of products P that are to be packaged. The products P are fed onto the packaging material F and transported onward by it. In a folding, sealing, and separating unit  8 , the packaging material F is folded and shaped into a tube of packaging material; individual bags containing the desired number of products are closed by the making of a longitudinal sealing seam and transverse sealing seams and separated from one another and leave this unit in the form of individual bags B for further processing or packaging. Between the packaging material delivery unit  6  and the folding unit  8 , the tear-open assistance unit  5  of the invention is now located. This is represented in  FIG. 8  by a “black box”. How this tear-open assistance unit  5  is effectively designed depends on which of the above-described packaging variants is to be attained. 
     In a first variant shown in  FIGS. 9   a  and  9   b , it has a folding roller  50 , which has two separately movable peripheral segments  51 . The two peripheral segments  51  can be guided counter to one another in the tangential direction, as represented by arrows in  FIG. 9   a . In the process, the interstice  52  between the two peripheral segments  51  decreases in size. The packaging material F, which is guided via this roller  50 , is everted outward when these segments move together, as can be seen from  FIG. 9   b . If the folding roller  50  is rotated onward, then the region of the packaging material F that protrudes from the roller  50  gets into the region of the sealing roller  53  or sealing jaw contacting the roller  50 , and the releasable seals can be made at the desired points. The protruding part can be perforated or cut at a desired point by the sealing roller  53  or a preceding or following cutting device. The packaging material F may already be in a form that has perforations made at constant spacings. This apparatus is suitable for producing the packages of  FIGS. 1 and 7 . 
     In the variant of  FIGS. 10   a  and  10   b , the folding roller  50  again has the two movable peripheral segments  51 . In the interstice  52 , a cutting and/or perforating device  57  is now provided, for cutting or perforating the packaging material at a desired point. This apparatus is suitable for producing the packages of  FIGS. 1 and 7 . 
     In  FIGS. 11   a  through  11   d , a further variant is shown; the individual drawings represent successive method steps. Here there are three rollers  54 ,  55 ,  56 , between which the length of packaging material F extends. In  FIG. 11   a , the three rollers  54 ,  55 ,  56  are first driven at the same rotary speed. The second roller  55  is not involved in transporting the length of packaging material, since it is located at some spacing, preferably approximately 0.1 mm, from the length of packaging material F guided on the first roller  54  and thus does not contact the packaging material. The first and third rollers  54 ,  56  transport the length of packaging material F thanks to the imposition of a vacuum or by other known means. The imposition of a vacuum is represented in subsequent drawings by arrows. In the next step in  FIG. 11   b , the second roller  55 , as before, is still not involved in transporting anything. However, the first roller  54  rotates at a higher speed than the third roller  56 , so that a fold is formed in the length of packaging material F. In  FIG. 11   c , all the rollers  54 ,  55 ,  56  now run at the same rotary speed, and the second roller  55  is now involved in transporting the packaging material. In this involvement region, it has cutting and/or perforating means  57 . In  FIG. 11   d , the cut made by the second roller  55  in the packaging material F can be seen. Also here, the vacuum in the second roller  55  is increased compared to that in the first roller  54 . If other means for putting the packaging material in contact with the rollers are used, then the applicable attraction force of the second roller  55  is increased compared to that of the first roller  54 . As a result, as can be seen from  FIG. 11   e , the packaging material is now pulled toward the second roller  55 . Thanks to the spacing between the first and second rollers  54 ,  55 , the first roller  54  can now form the next fold. In  FIG. 1  if, it can be seen how the first fold is transported onward, thanks to the second and third rollers  55 ,  56 , which now run at the same speed; in the region adjacent to the first roller  54 , the second roller  55  no longer has any vacuum. This apparatus is suitable for producing the packages of  FIGS. 1 and 7 . 
     In the variant of  FIG. 12 , a different arrangement of the above-described three rollers  54 ,  55 ,  56  is shown. The axes of rotation  54 ′,  55 ′,  56 ′ of the rollers  54 ,  55 ,  56  in  FIGS. 11   a  through  11   d  are arranged in an equilateral triangle, and the delivery of packaging material F is done parallel to a side of the triangle that is formed by the first and second rollers  54 ,  55 . Carrying the packaging material F away is done perpendicularly to this. In the arrangement shown in  FIG. 12 , the axes of rotation  54 ′,  55 ′,  56 ′ form an isosceles triangle, and the packaging material F is delivered and carried away parallel to the side of the triangle that is formed by the axes of the first and third rollers  54 ,  56 . This arrangement has the advantage that the directions of delivering and carrying away the packaging material F are aligned. 
     In  FIG. 13 , a further preferred apparatus for producing such bag packages is shown. Once again, this is a bag package packaging machine of a known type, in particular a horizontal bag package packaging machine, which for forming the tearing aid is provided with a tear-open assistance unit  5  of the invention. 
     In this tear-open assistance unit  5 , the perforating means  90 ,  91  precede the means  94 ,  95  for furnishing the overlap of material in the conveying direction of the film F. As the perforating means  90 , a cutting roller  90  and a counterpressure roller  91  can for instance be used. Adjoining these rollers  90 ,  91 , the perforated packaging film F is conveyed along a vacuum belt  92  and reaches a packaging material reservoir  93 . This packaging material reservoir  93  is optional. Adjacent to the packaging material reservoir  93 , two roller pairs  94 ,  95 , located one after the other in the conveying direction, follow, and the overlap of material is produced and fixed between them. The film thus provided with overlapping regions is guided via deflection rollers  96  to the folding, sealing, and separating unit. 
     In  FIGS. 14   a  through  14   c , the roller pairs  94 ,  95  are shown. Thin lines symbolically also show the perforation means, in the form of two opposed rollers. The film F is first passed between the first roller pair  94 . Between the two roller pairs  94 ,  95 , there is a means for intentionally subjecting the film F to force. The force imposition by this means is represented by a triangle in the drawing and identified by reference numeral  98 . The apex of the triangle pointing toward the film F is intended to indicate the direction of force imposition. As such means, air jets that blow at the film F can for instance be used. However, this means may also be a suction device that subjects the film to a vacuum. It is understood that still other means known in the prior art for deflecting the film F can also be used. To assure that the film F is not deflected until just before the second pair of rollers  95 , it preferably, adjoining the first pair of rollers  94 , extends in a guide  97 . This guide  97  can be formed for instance by two parallel baffles such as metal or plastic plates, which limit the travel of the film F from above and below. 
     As can be in  FIG. 14   a  from the arrows of equal size, first both pairs of rollers rotate at the same rotary speed. If the rotary speed of the first roller pair  94  is then increased relative to the second roller pair  95 , as is represented in  FIG. 14   b  by the arrows of different sizes, then the film F becomes backed up upstream of the second pair of rollers  95  and is purposefully deflected by the force imposition  98 . The force imposition preferably takes place only purposefully along with the increase in the rotary speed, so that the film regions between two overlap of materials are not subjected to force on passing through this point. It can then be seen in  FIG. 14   c  that because of the different speeds of the two pairs of rollers  94 ,  95 , an overlap of material has now developed in the region of the perforation of the film F. This overlap can now be transported through the second pair of rollers  95  and fixed in its position either on passing through this pair of rollers  95  or just after that, in the manner already described above. 
     As can be seen from the various examples, the package or bag according to the invention can be produced from a flexible material and has an opening mechanism with a seal that is suitable for separating, by pulling off one segment or part of the bag from the rest of the bag, here called the main body. This part of the bag is joined to the rest by a nonpermanent seal, which detaches in response to a corresponding tensile or compressive stress, and as a result, one part of the bag can be separated from the rest. The detachable part of the bag package can be selected to be of arbitrary size. Cold glue is especially suitable as a nonpermanent seal. In some of the exemplary embodiments, the part of the bag that can be pulled off from the rest is partly everted around itself and is joined in this region to the rest via a nonpermanent, detachable seal. One part thus protrudes into the other and can be pulled out. Hence there are three layers of material in this region. When a pull is exerted on one or both ends of the bag, the film sealed on the inside against the main body is progressively released and rolls in the direction of the tension. On arriving at the end, the pulled-off bag segment detaches, and the bag is completely and cleanly open. 
     It is understood that the package according to the invention and the apparatus according to the invention can be modified in manifold ways without departing from the concept of the invention. In particular, the tearing aid  3  can be cut or perforated either before or after the detachable sealing seam is applied. Instead of a detachable seal, some other detachable type of connection can be used, in particular an adhesive bond. The sealing can be done by known means. In particular, it can be cold or hot sealing. An already preperforated film can also be used, so that in this case perforating means integrated into the tear-open unit  5  are unnecessary. 
     The foregoing relates to a preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Package 
           10  First package region 
           11  Second package region 
           2  Transverse sealing seams 
           3  Tearing aid 
           30  Overlapping region 
           31  Packaging material fold 
           32  Packaging material edge region 
           33  Detachable sealing seam 
           35  First edge 
           36  Second edge 
           37  Strip 
           38  Perforation line 
           5  Tear-open assistance unit 
           50  Folding roller 
           51  Peripheral segment 
           52  Interstice 
           53  Sealing roller 
           54  First roller 
           54 ′ First axis of rotation 
           55  Second roller 
           55 ′ Second axis of rotation 
           56  Third roller 
           56 ′ Third axis of rotation 
           57  Cutting or perforating means 
           6  Packaging material delivery unit 
           7  Product delivery unit 
           8  Folding, sealing, and separating unit 
           90  Cutting roller 
           91  Counterpressure roller 
           92  Vacuum belt 
           93  Packaging material reservoir 
           94  First roller pair 
           95  Second roller pair 
           96  Deflection roller 
           97  Guide 
           98  Imposition of force 
         P Product 
         F Packaging material 
         B Bag