MXPA01000370A - Method and machine for making a string of bags provided with transverse closure profiles and resulting articles - Google Patents

Abstract

The invention concerns a method for making a string of bags provided with transverse closure profiles (20), comprising steps which consist in:sequentially depositing sections of a closure system (20) including two matching closure profiles (22, 24) transversely on a film (10) designed to form the walls of the bags, and fixing the support webs (21, 23) of said two matching closure profiles (22, 24) respectively on the inner surfaces of the bag two walls, while making sure that a transverse opening (12) is sequentially provided in the film enabling access between the two profiles (22, 24). The invention also concerns a machine for implementing said method and the resulting strings of bags.

Description

A METHOD AND A MACHINE TO MANUFACTURE A ROW OF BAGS PROVIDED WITH TRANSVERSAL CLOSURE STRIPS, AND ARTICLES OBTAINED WITH THE SAME DESCRIPTIVE MEMORY The present invention relates to the field of manufacturing bags in a "row", ie bags that are connected one after the other upon leaving the manufacturing process, but which are suitable to be separated during a subsequent filling step or after filling. The present invention relates more precisely to the manufacture of bags provided with appropriate complementary closure strips to allow the bags to open and close alternately, if required. Various procedures have already been proposed for this purpose. In general, the systems currently known and used to make rows of bags are adapted to make rows in which the bags have longitudinal openings, that is, openings located along one of the longitudinal edges of the row. Examples of such known means for making such swaths can be found in WO-A-94/19250 and EP-A-0 054 564.

The rows of bags obtained in this way have already given good service. However, these do not always provide satisfaction. In particular, such rows of bags with longitudinal openings require that the row be wound in a generally horizontal direction, if the bags are to be filled only by gravity. A configuration as such requires a voluminous installation. It also requires complex means to guide the bags. Attempts have been made to avoid such difficulties by proposing means designed to make rows of bags having transverse openings. However, current attempts in those directions have not provided complete satisfaction either. Therefore, document US-A-5 118 202 proposes means for manufacturing a row of bags, adapted to place the strips for closure longitudinally, while at the same time creating transverse openings on the rows. These facilities have complex means to elaborate the transverse openings, and above all these require a joining operation to close the bags after they have been filled, since the closing strips can not be used for that purpose since the strips Closure extend longitudinally and not transversely as the openings. WO-A-97/06062 discloses other means for manufacturing a row of bags with transverse openings, adapted to place the strips for closure in transverse form.

However, in this case also the means of implementation are complex. In particular, these require a closure system having two complementary female / male strips whose support meshes are fixed on a common sheet of the bag. DE-A-3 824 753 discloses a method for manufacturing a row of bags and the row of bags obtained therefrom, using film which is supplied on a filling channel and which is provided with complementary cross-strips for closing. An object of the present invention is to propose novel means designed to make a row of bags. In accordance with the present invention, this object is achieved by a method comprising the steps of sequentially positioning the segments of the closure system transversely on at least one film forming the walls of the bag, each segment two complementary strips for closing, fixing the support meshes of the two closing strips complementary respectively to the inner faces of the two walls of the bag, and providing sequential transverse openings through a part of the film so as to be access between the two strips from the outside of the closure system in relation to each bag. In a preferred implementation, the method of the present invention consists in placing transversely on the film segments of the closure system of a length that is approximately half the width of said film, cutting the film transversely substantially over half of its width outside the closure system , fold the film over itself, and fix the support meshes of the two strips of the closure system to the two walls of the bag, respectively. The present invention also provides a machine for implementing the above method, and the rows of bags obtained therefrom. The machine comprises means for sequentially positioning the segments of the closure system transversely on at least one film forming the walls of the bag, each segment comprising two complementary closure strips, means for fixing the support meshes of the two strips for closure respectively complementary to the inner faces of the two walls of the bag, and the machine is characterized in that it comprises means for providing transverse openings in sequence through a part of the film so as to be accessible between the strips from the outside of the closure system in relation to each bag. Still more precisely, the machine of the present invention preferably comprises means for transversely positioning on the film segments of the closure system of a length that is approximately half the width of said film, cutting the film transversely substantially about half of its width outside the closure system, bending the film on itself, and fixing the support meshes of the two strips of the closure system to the two walls of the bag, respectively. The rows of bags of the present invention have segments of closure system comprising pairs of complementary closure strips with support meshes that are fixed transverse respectively to the inner faces of the walls of the bags, the rows being characterized by a transverse opening provided through a part of the film to provide access between the two strips from the outside of the closure system relative to each bag. Other features, objectives and advantages of the present invention will appear on reading the following detailed description with reference to the attached drawings given as non-limiting examples in which: Figures 1, 2, 3 and 4 are diagrams showing 4 successive steps in a method of manufacturing a row of bags in accordance with the present invention. Figure 5 shows a variant of the step of figures 1, when the closing strips are out of center. Figure 6 is a diagram showing a row of bags of the present invention. Figure 7 is a cross-sectional view through the mouth of a bag of the present invention in a variant embodiment in which the closure strips are assembled in the open position.

Figure 8 shows a row of bags of the present invention placed on a roll. Figure 9 is a cross-sectional view through a bag of the present invention made using two separate sheets of film. Figures 10 and 11 are sectional views through the closure strips in two variant embodiments of the present invention. Figure 12 is a similar view of the closure means showing an insulator insert inserted between the support meshes to prevent them from adhering to each other. Figure 13 is another view of the closure means constituting a variant having support meshes of different widths. Figure 14 is another view of such closure means having a single support mesh that is fixed to the film only in part. Figure 15 is a view similar to Figure 5 showing another variant embodiment; and Figure 16 is a final view of the manufacturing process. The preferred method of the present invention is described initially with reference to the attached figures 1 to 4. Figure 1 shows a step which consists in placing the segments of closure system 20 on a film 10. During this step, the film 10 preferably travels continuously in the length direction, ie in the direction D. The segments of the closure system 20 are placed transversely on the film 10, ie perpendicular to the direction D. In a variant, the Movie 10 could travel intermittently. During this step, the support mesh 21 of the lower closure strip 32 adjacent the film 10 is bonded thereto. The segments of the closure system 20 are of a length L1 that is equal to half the width L2 of the film 10 or substantially equal to half of said width L2. As shown in Figure 1, the segments of the closure system 20 are centered over the width of the film 10. However, in a variant, it is possible to contemplate placing the segments of the closure system 20 out of center relative to the width of the film 10. to the film 10, for example by placing the segment 20 at least substantially adjacent one of the edges of the film 10. One such variant with off-center segments 20 is shown in Figure 5. The closure strips 20 may be implemented in several ways. Preferably they are, respectively, a male strip 22 and a complementary female strip 24 carried by the respective support meshes 21 and 23. Such a modality is shown in diagram form in figure 10. The structure of such male strips 22/24 / complementary female is conventional and therefore not described in more detail later.

However, in a variant such as that shown in Figure 11, the complementary closure strips 20 may be constituted by hook-shaped structures 22a, 22b, 24a, and 24b similarly carried by the meshes 21 and 23 respective. As shown in Fig. 2, the film 10 is then cut transversely and in sequence in the vicinity of the segments 20, but the cutting line 12 is not limited to the portions outside the closure segments 20. When the closing strip segments 20 are centered on the film 10, thus two aligned cutting lines are formed, each being of a length that is equal to approximately one quarter of the width L2 of the film 10 and each of the openings with respect to one of the longitudinal edges of the film 10. The cutting lines 12 are made in areas of the film that rest outside the bags in relation to the closure strips 20. When appropriate, it is possible to cut previously a weakening line 14 between the cutting segments 12 simultaneously. Such a weakening line 14 aims to make it easier to separate the bags later. This line of weakness 14 can be constituted by a run of perforations. After this, as shown in figure 3, the film bends on itself and the two longitudinal edges 15 and 16 of the film 10 are joined together. This is marked with the number 17 in figure 3.

After this, as shown in Figure 4, the support mesh 23 of the upper closure strip 24 is attached to the adjacent wall of the formed pouch by bending it over the film 10. Simultaneously, the two walls of the bag are joined transversely in the bottom 18 of the bag. The joint 18 must be made naturally at a distance from the strips 20, through the cutting line 12. The distance between the strips 20 and the joint 18 defines the depth of the bags. As shown in Figure 6, this gives rise to a row of bags having transverse closure strips 20 which are directly accessible by the cut lines 12. Therefore, to fill these bags it is sufficient to open the closure system 20 and then close it again on the contents of the bag. In a variant shown diagrammatically in FIG. 7, it is possible to feed the segments of closure strip 20 and fix them to the walls of the bag in the open state, ie in a state in which the two strips for closing 22 and 24 are separated. In this configuration, the two closing straps 22 and 24 are nevertheless preferably joined at their ends to the respective joints 25, 26. As shown in the form of a diagram in FIG. 8, a row of bags can be rolled up before fill them, so that an appropriate roll is formed to feed a packing machine. The packing machine preferably has appropriate means for opening the closure systems 20 if they are previously closed, for filling the bags by gravity, and for reclosing the systems 20. Where appropriate, the closure of the bag may be accompanied by joining the walls of the bag, outside the closure systems 20. The bags can be easily separated one from the other by breaking the lines of weakness 14. The means of the present invention make it possible to make a row of bags provided each one with complementary closure strips 20 and suitable for automatic packaging. These means are simple. Also, while the bags are filling up, the means to guide the row can also be very simple. It suffices to only have an arrow that supports the row of rolled bags. Various means can be provided to prevent the strips 22 and 24 of the support meshes 21 and 23 from adhering to each other, during the steps in which the closure assemblies 20 are attached to the film 10. As an example , Figure 12 shows that it is possible to provide an insert 30 associated with heat sealing tongs and suitable for being placed between the support meshes 21, 23. In another variant, at least one of the support meshes 21 and 22 can to be implemented in the form of a multi-layered structure each having an outer layer and an inner layer in which the outer layers have a melting temperature that is lower than that of the inner layers.

In yet another variant, as shown in the diagram in FIG. 13, the support meshes 21 and 22 may be provided with different widths. Under such circumstances, the wider support mesh preferably corresponds to the upper support mesh which is the last to be fixed to the film 10. It is also possible to join at least one of the support meshes 21, 23 through only a fraction of its width, preferably using the longitudinal margin of the support mesh which is located towards the outside. A variant as such is shown in Figure 14 for the upper mesh 23. This variant allows the pressure inside the bag to tend to raise the area of the supporting mesh 23 underlying the strips away from the film 10, thereby tending to act on the strips 22 and 24 mutually engaged. Even in another variant, the closing system 20 can be equipped with a drive slide. Conventionally, such a slide makes it easier to handle the closure strip 22 and 24, both for opening and closing. A person skilled in the art knows various embodiments of such slides, so that such slides are not described in detail later. However, in the context of the present invention, it is preferred that each of the slides comprises a single plate carrying two side edges on one of the sides together with a central separation rib that functions in conjunction with the two side edges to define two convergent / divergent passages (depending on the direction of trajectory) to receive respectively those of the strips 22 and 24. Each of the segments of closure system 20 may be previously equipped with a slider when it is put in its place. However, in a variant, the slides can be added to the closure strips 20 after they have been fixed to the film 10, at least after the first support mesh 21 has been fixed to the film 10. Examples of suitable means for adding a slide are found in EP-A-0 510 100, EP-A-0 102 301, and EP-A-0 479 661. The film cula 10 (or sheets 10a and 10b) can be implemented in different ways. These may be a single film of thermoplastic material or a multilayer thermoplastic film, ie a film made from a plurality of juxtaposed layers of different types, or a laminated film made for example of paper coated with a layer of plastic materials , or a metallized film. Of course, the present invention is not limited to the modalities described above, but extends to any of the variants within its field. Therefore, as shown for example, in the form of a diagram in Figure 9, it is possible in a variant to contemplate making rows of bags using two sheets of film 10a and 10b which are superposed instead of using a single film 10. Under in such circumstances, care must be taken to ensure that a cut line is made in at least one of the two sheets 10a, 10b to give access to the closure strips 20 or otherwise, to feed this sheet (preferably the upper sheet 10b) in the form of successive segments of a length corresponding to the depth of the bags. The two sheets 10a and 10b are joined together along their longitudinal edges 15 and 16 as shown in diagram form at numbers 17a and 17b of Figure 9. Even in another variant, the aforementioned unions, in particular the joints between the walls of the bag outside the closure strips 20 and extending transversely after the bags have been filled are not made by heat sealing, but by adhesive. For this purpose, it is possible to place an appropriate strip of adhesive, preferably a strip of adhesive material on one of the walls of the film in the mouth of each bag. To prevent the strip from adhering to a wall of the bag too soon and in the wrong place, the adhesive strip can be coated on a release film. The variant mode shown in Figures 15 and 16 is described below. In the embodiments described above, the strips 22 and 24 are placed facing each other (and hooked together in the manner shown in Figures 1 to 5, or conversely separated but connected together by their ends in the mode shown in figure 7) when these are fed transversely on the film 10. On the contrary, in the variant shown in figures 15 and 16, when the complementary strips 22 and 24 are supplied in the film 10, these are not face each other but instead they are aligned, that is, one after the other when they move through the film 10 transversely. Accordingly, the support meshes 21 and 23 carrying the respective closure strips 22 and 24 are preferably then joined to the film simultaneously and not successively as described above. However, in a variant, it is even possible to contemplate the mesh 21 from the beginning and to join the mesh 23 subsequently, for example after the film has been folded. The strips 22 and 24 can be constituted by separate strips which are supplied on the film in succession or they can be connected together in the position shown in Figure 15 when they are simultaneously supplied on the film 10. The strips 22 and 24 are placed subsequently to face one another during a step in which the film 10 is folded over itself, as shown in Figure 16. During this operation, the strips 22 and 24 can move while being engaged, or in in a variant these can be kept facing one another but separated by making the hook later only after the bag has been filled. The subsequent manufacturing operations of the bag (essentially the longitudinal bond l between the edges of the film and the transverse junction 18) remain essentially the same as in the variants described above. In particular, it should be noted that in this case it is also preferred that the film 10 be separated to half its width before being folded over itself so that the necessary transverse opening is formed to give access to the portion between the strips 22. and 24. In Figure 15, the cut line is thus formed through the film 10 over half its width and is referenced by the number 12. This cut line 12 preferably extends by a line of weakening 14 so that it becomes easier to separate the bags later.

Claims (53)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A method for manufacturing a row of bags provided with transverse closing strips (20), the method comprises the steps which consist in consecutively placing segments of closure system (20) transversely in at least one film (10) for forming the walls of the bag, each segment comprises two complementary closing strips (22, 24), fixing the support meshes (21, 23) of the two complementary closure strips (22, 24) respectively to the internal faces of the two walls of the bag, and provide sequential transverse openings (12) through part of the film so as to have access between the two strips (22, 24) from the outside of the closure system with respect to each bag.
2. 2. The method according to claim 1, further characterized in that the opening (12) is formed by cutting the film (10) transversely out of the closure system (20).
3. 3. The method according to claim 2, further characterized in that the film (10) is folded on itself after making the cut (12).
4. 4. The method according to any of claims 1 to 3, further characterized by the fact that it consists of transversely placing segments of the closure system (20) of a length (L1) transversely in the film (10). which is about half the width (L2) of said film, cutting (12) the film (10) transversely over substantially half of its width outside of the closure system (20), folding the film (10) over itself, and fixing the support meshes (21, 23) of the two strips (22, 24) of the closure system (20) towards the two walls of the bag, respectively.
5. 5. The method according to claim 3 or 4, further characterized in that the support mesh (21) of the lower closure strip (22) adjacent to the film (10) is attached thereto before that the film (10) is folded, and by the fact that the support mesh (23) of the upper closure strip (24) joins the film after it has been folded.
6. 6. The method according to any of claims 1 to 5, further characterized by the fact that the segments of closure system (20) are centered across the width of the film (10).
7. 7. The method according to any of claims 1 to 5, further characterized by the fact that the segments of the closure system (20) are off center through the width of the film (10).
8. 8. The method according to any of claims 1 to 7, further characterized by the fact that the complementary strips (22, 24) do not face each other but are aligned, when fed to the film (10) .
9. 9. The method according to any of claims 1 to 8, further characterized in that it also comprises the step consisting of joining the longitudinal edges (15, 16) of the film (10) after at least one fold has been formed in the film (10).
10. 10. The method according to claim 1, further characterized in that it is made from two sheets of superimposed films (10a, 10b).
11. 11. The method according to claim 10, further characterized in that it comprises a step which consists in forming a cutting line in at least one of the two sheets (10a, 10b) to give access to the strips closing (20).
12. 12. The method according to claim 10, further characterized in that it comprises the step which consists in feeding one of the sheets (10b) in the form of successive segments of length corresponding to the depth of the bags.
13. 13. The method according to any of claims 10 to 12, further characterized in that it comprises a step which consists in joining the two sheets (10a, 10b) along their longitudinal edges (15, 16). ). 14. - The method according to any of claims 1 to 13, further characterized in that it comprises a step which consists in making a line of weakness (14) between the lines of cut (12) in the portion of film that forms a wall of the bag. 15. The method according to any of claims 1 to 14, further characterized by the fact that it comprises the step which consists in uniting transversely the two walls of the bag in the lower part (18) of the bag . 16. The method according to any of claims 1 to 15, further characterized by the fact that it comprises the step which consists in feeding the segments of closure strip (20) and fix them to the walls of the bag, while the segments are in the open state. 17. The method according to claim 16, further characterized in that it comprises the step which consists in previously joining the two closing strips (22, 24) at their ends through respective unions (25, 26). ). 18. The method according to any of claims 1 to 17, further characterized by the fact that comprises the step which consists of winding the row of bags before being filled to form a roll suitable for feeding a machine packer 19. - The method according to any of claims 1 to 18, further characterized by the fact that during the steps of fixing the closure strips (20) in the film (10), an insert is placed (30) associated with heat sealing tongs between the support meshes (21, 23). 20. The method according to any of claims 1 to 18, further characterized in that the support meshes (21, 23) of the closure strips are constituted by multiple layer structures, each comprising a layer external and an inner layer, wherein the outer layer has a melting temperature that is lower than that of the inner layer. 21. The method according to any of claims 1 to 18, further characterized in that the support meshes (21, 23) of the closure strips (22, 24) are of different widths. 22. The method according to claim 21, further characterized by the fact that the widest support mesh corresponds to the upper support mesh which is the last to be fixed to the film (10). 23. The method according to any of claims 1 to 22, further characterized by the fact that comprises the step which consists in joining at least one of the support meshes (21, 23) on a fraction only of its width. 24. - The method according to any of claims 1 to 23, further characterized in that the closing system (20) is adjusted with a drive slide. 25. The method according to any of claims 1 to 24, further characterized in that it comprises the step which consists of placing an adhesive strip, preferably a strip of adhesive material optionally covered with a strip removable, in one of the walls of the film, in the mouths of the bags. 26.- A machine for manufacturing a row of bags provided with transverse closing strips (20), the machine comprises means for consecutively placing closure system segments (20) transversely in at least one film (10) to form the walls of the bag, each segment comprising two complementary closure strips (22, 24), means for fixing the support meshes (21, 23) of the two complementary closure strips (22, 24) respectively to the internal faces of the two walls of the bag, the machine being characterized in that it comprises means for providing consecutive transverse openings (12) through part of the film so as to provide access between the two strips (22)., 24) from outside the closure system in relation to each bag. 27. The machine according to claim 26, further characterized in that it comprises means for transversely placing in the film (10) segments of closure system (20) of a length (L1) which is approximately half the width (L2) of said film, cut (12) the film (10) transversely over substantially half of its width outside the closure system (20), bend the film (10) on itself and fix the support meshes (21, 23) of the two strips (22, 24) of the closure system (20) towards the two walls of the bag, respectively. 28. The machine according to claim 26 or 27, further characterized in that the segments of closure system (20) are centered on the width of the film (10). 29. The machine according to claim 26 or 27, further characterized in that the segments of the closure system (20) are off center through the width of the film (10). 30. The machine according to any of claims 26 to 29, further characterized by the fact that it also comprises suitable means for joining the longitudinal edges (15, 16) of the film (10) after the film (10). ) has been folded at least once. 31.- The machine according to claim 26, further characterized in that the bags are made of two overlapping film sheets (10a, 10b). 32. The machine according to claim 31, further characterized in that it comprises suitable means for forming lines of cut in at least one of the two sheets (10a, 10b) to give access to the closure strips (20). ). 33. - The machine according to claim 31, further characterized in that it comprises suitable means for feeding one of the sheets (10b) in the form of successive segments of length corresponding to the depth of the bags. 34.- The machine according to any of claims 31 to 33, further characterized in that it comprises suitable means for joining the two sheets (10a, 10b) along their longitudinal edges (15, 16). 35.- The machine according to any of claims 26 to 34, further characterized by the fact that it comprises suitable means to make a line of weakness (14) between the lines of cut (12) in the portion of film forming a wall of the bag. 36.- The machine according to any of claims 26 to 35, further characterized by the fact that it comprises suitable means for joining transversely the two walls of the bag in the lower part (18) thereof. 37.- The machine according to any of claims 26 to 36, further characterized in that it comprises suitable means for winding the row of bags before filling in order to form a roll suitable for feeding a baler. 38.- The machine according to any of claims 26 to 37, further characterized by the fact that it comprises suitable means to prevent the closing strips (22, 24) and / or their support meshes (21, 23) stick while they are attached to the movie (10). 39.- The machine according to any of claims 26 to 38, further characterized by the fact that it includes an insert (30) associated with heat sealing tongs, insert which is placed between the support meshes (21, 23) during the steps of fixing the closing strips (20) to the film (10). 40.- The machine according to any of claims 26 to 39, further characterized by the fact that the support meshes (21, 23) for the closure strips are constituted by multiple layer structures, each comprising a layer external and an inner layer, where the outer layer has a melting temperature lower than that of the inner layer. 41.- The machine according to any of claims 26 to 40, further characterized by the fact that the support meshes (21, 23) of the closure strips (22, 24) are of different widths. 42.- The machine according to any of claims 26 to 41, further characterized in that it comprises means suitable for receiving a closure system (20) adjusted with a drive slide or suitable means for adjusting the closure system with said slide. 43. - The machine according to any of claims 26 to 42, further characterized in that it comprises suitable means for placing on the one of the walls of the film, in the mouths of the bags, an adhesive strip, preferably a strip of adhesive material covered when convenient, in a strip of release film. 44.- A row of bags obtained by implementing the method according to any of claims 1 to 25 and / or when using a machine according to any of claims 26 to 43, the row comprising segments of the closing system (20). ) comprising pairs of complementary closure strips (22, 24) with support meshes (21, 23) which are fixed transversely respectively to the inner faces of the walls of the bags, the row being characterized by the fact that it comprises a transverse opening through part of the film to provide access between the two strips from the outside of the closure system with respect to each bag. 45.- The row of bags according to claim 44, further characterized by the fact that it is made using a simple film (10) folded on itself. 46.- The row of bags according to claim 44, further characterized by the fact that it is made using two sheets of superimposed films (10a, 10b). 47. The row of bags according to any of claims 44 to 46, further characterized by the fact that it has a line of weakness (14) between each pair of adjacent bags. 48.- The row of bags in accordance with any of the * 5 claims 44 to 47, further characterized by the fact that it is presented in the form of a roll suitable for feeding to a packing machine. 49.- The row of bags according to any of claims 44 to 48, further characterized by the fact that the 10 support meshes (21, 26) of the closure strips are formed of multi-layer structures, each comprising an outer layer and an inner layer, in which the outer layer has a melting temperature which is lower than the melting temperature of the inner layer. 9 50.- The row of bags according to any of the 15 claims 44 to 48, further characterized by the fact that the support meshes (21, 23) of the closing strips (22, 24) are of different widths . 51.- The row of bags according to any of claims 44 to 50, further characterized by the fact that at least one of the support meshes (21, 23) is joined over a fraction only of its width. 52. - The row of bags according to any of claims 44 to 51, further characterized by the fact that the closure system (20) is adjusted with a drive slide. 53. The row of bags according to any of claims 44 to 52, further characterized by the fact that in one of the film walls, in the mouths of the bags, a strip of adhesive is included, preferably an adhesive strip. strip of adhesive material that is covered, when convenient, in a strip of release film. I f