METHOD AND MACHINE FOR MANUFACTURING A FLEXIBLE ENVELOPE-LIKE BAG, PARTICULARLY WITH REINFORCEMENT

Abstract

A method for manufacturing flexible bags, including: a first strip of flexible material is unwound as a continuous sheet in a longitudinal direction; a hem is formed on each edge of the first strip and the hems are glued over at least one length of a first or a second flap on one stitching face; a fold is formed in the first strip along a transverse folding line to fold down the first flap over the second flap against an internal face of the first strip, the fold bringing, for each edge, hem against hem so as to obtain the bonding of the hems, the strip is cut along a transverse section to form the bag at the end of the operations. Machine implementing the method and bag thus obtained.

Claims

1. A process for manufacturing flexible bags, whereby: a first strip of flexible material is unreeled as a continuous sheet in a longitudinal direction, a fold is made on the first strip along a transversal folding crease to fold a first flap onto a second flap against an internal face of the first strip, the first and second flap are brought together along the edges, the strip is cut by a transversal cut to form a section before or after the folding of the flaps one onto the other, the section forming the bag at the end of the operations, wherein a hem is formed on each edge of the first strip before folding and adhesive is applied to the hems at least over one length of the first or second flap on one seam face, the folding bringing for each edge hem against hem by the seam face in such a way as to obtain bonding of the hems to each other to bring the first and the second flaps together along the edges.

2. The process according to claim 1, whereby: at least one reinforcement layer is unreeled, the reinforcement layer is cut to obtain a system with at least one reinforcement panel, a first application of adhesive is made at least on one of the elements among the first strip and the system with at least one reinforcement panel, before folding, the first strip and the system with at least one reinforcement panel are brought together on the internal face of the first strip to stick them together by means of a first application of adhesive, in such a way that the system with at least one panel is situated between the first and second flaps.

3. The process according to claim 1, whereby the length of the flaps is not the same in the longitudinal direction, in such a way that the second flap comprises a tab that is not covered by the first flap after folding, the tab not being covered by the system with at least one reinforcement panel.

4. The process according to claim 1, whereby a second strip of flexible material is unreeled, a second application of adhesive is made, and the second strip and the first strip are brought together on the internal face of the first strip so they adhere to each other thanks to a second application of adhesive.

5. The process according to claim 2, whereby the system with at least one reinforcement panel is taken between the first and second strips.

6. The process according to claim 4, whereby the widths of the first and second strips are different in such a way that the hems extend from just one of said strips.

7. The process according to claim 4, whereby the width of the second strip is the same as that of the first strip.

8. The process according to claim 2, whereby a cheek is also formed on each edge of the first strip, the cheek being folded against the internal face and extending between the hem and a central part of the strip, in such a way that a stack is formed with, in the following order, the central part, the cheek and the hem, the cheeks forming a bellows linking the first and second flaps after bonding of the hems, the reinforcement panel not extending over the cheeks.

9. The process according to claim 8, whereby the separate reinforcement strips are placed on the cheeks.

10. The process according to claim 2, whereby the system with at least one reinforcement panel comprises a single panel which extends over the first and second flaps.

11. The process according to claim 2, whereby, in order to form the system with at least one reinforcement panel, two reinforcement panels are successively cut and positioned, one on the first flap and the other on the second flap leaving an interval between them at the level of the folding crease.

12. The process according to claim 1, whereby an area of closing adhesive and a protection strip is applied to the closing adhesive area so they can be seen on the tab when the first flap is visible.

13. The process according to claim 1, whereby the hem is also stuck to the face opposite the seam face along just one of the elements among the first and second flap.

14. A bag made of a flexible material comprising a first and a second flap extending from a given sheet folded along a transversal folding crease towards an internal face and brought together along the edges of the flaps perpendicular to the folding crease, wherein the bag comprises a hem formed on each edge, the hem on the first flap being bonded to the hem of the second flap on the seam faces.

15. The bag according to claim 14, in which the hem is linked to a central part of the flap by means of a cheek folded onto the central part, in such a way that a bellows is formed by two cheeks brought together by the hems bonded to each other.

16. The bag according to claim 14, in which the system with at least one reinforcement panel extends against the internal face of the flaps.

17. The bag according to claim 14, whereby a second strip of flexible material is bonded to the internal face of the first strip of flexible material and the second strip of flexible material covers the reinforcement panel.

18. The bag according to claim 16, whereby the system with at least one panel comprises several superposed reinforcement panels, the reinforcement panels having decreasing widths, each reinforcement panel being bonded to one among the first and second strips by the surface not covered by the adjacent panel.

19. The bag according to claim 14, whereby the first flap is shorter than the second flap and leaves a tab on the second flap not covered by the first flap.

20. A machine for manufacturing flexible bags comprising: a first unwinding means for unreeling a first strip of flexible material in a continuous sheet in a longitudinal direction; a folding means for forming a fold of the first strip along a transversal folding crease for folding a first flap onto a second flap against an internal face of the first strip, an assembly means for bringing the first and second flaps together along the edges, a first cutting means for cutting the strip with a transversal cut to form a section upstream or downstream of the assembly means, the section forming the bag at the end of the operations; a hemmer for each edge, to form a hem on each edge of the first strip upstream of the assembly means, an application means for applying adhesive to the hems over at least one length of the first or second flap on a seam face, the assembly means being folding means configured to bring for each edge hem against hem by the seam face in such a way as to obtain the bonding of the hems together to bring the first and second flaps together along the edges.

21. The machine according to claim 20, wherein the machine comprises: a feed means for supplying at least one layer of reinforcement, a second feed means for cutting the reinforcement layer and thus obtain a system with at least one reinforcement panel, a first adhesive application means to make a first application of adhesive at least on one of the elements among the first strip and the system with at least one reinforcement panel, an intake means, upstream of the folding means and downstream of the first adhesive application means and of the feed means, configured to bring the first strip and the system with at least one reinforcement panel together on the internal face of the first strip to bond them together thanks to the adhesive application, in such a way that the system with at least one panel is situated between the first and the second flap.

22. The machine according to claim 20, further comprising: a second unwinding means to unreel a second strip of flexible material, a second means of adhesive application to make a second application of adhesive, an intake means configured to also assemble the second strip and the first strip on the internal face of the first strip so that they adhere together thanks to the second adhesive application.

23. The machine according to claim 20, further comprising a cheek formation station also configured to form a cheek on each edge of the first strip, the cheek being folded against the internal face and extending between the hem and a central part of the strip, in such a way that a stack is formed with, in the following order, the central part, the cheek and the hem, the cheeks forming a bellows linking the first and second flap after the bonding of the hems, the system with at least one reinforcement panel only extending over the cheeks.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0064] The invention will be better understood and other features and advantages will appear on reading the following description, the description referring to the attached drawings among which:

[0065] FIG. 1 is a perspective view of a bag as per a first accomplishment mode;

[0066] FIG. 2 is a transverse sectional view of the bag in [FIG. 1];

[0067] FIG. 3 is a view similar to [FIG. 1] of the closed bag;

[0068] FIG. 4 is a perspective view of a partially made bag in [FIG. 1] during manufacturing;

[0069] FIG. 5 is a view similar to [FIG. 1] of a bag as per a second accomplishment mode;

[0070] FIG. 6 is a transverse sectional view of the bag as per a third accomplishment mode;

[0071] FIG. 7 is a sectional view as per a middle plane of the bag in [FIG. 6];

[0072] FIG. 8 is a top view of the bag in [FIG. 6];

[0073] FIG. 9 is a view similar to that in [FIG. 8] of a bag with bellows;

[0074] FIG. 10 is a schematic view of a machine conform to a first accomplishment mode of the invention;

[0075] FIG. 11 is a schematic view of a machine conform to a second accomplishment mode of the invention;

[0076] FIG. 12 is a schematic view of the first strip in the machine in [FIG. 8] for the lower part and in the machine in [FIG. 9] for the upper part of the view;

[0077] FIG. 13 is a schematic view of the assembly of the strips before being cut into sections.

DETAILED DESCRIPTION

[0078] A bag 1 envelope as per the invention's first accomplishment mode is shown in FIGS. 1 to 4. The bag 1 made with a flexible material comprises a first and second flap 11, 12 extending from the same sheet folded along a transversal folding crease 13 towards an internal face 14. The flaps 11, 12 are brought together along their edges which are perpendicular to the folding crease 13. A hem 15 is formed on each edge and bonded to the internal face 14 of the second flap 12. Furthermore, the hem 15 of the first flap 11 is bonded to the hem 15 of the second flap 12 on seam faces 150. The first flap 11 is shorter than the second flap 12 in such a way that a tab 16 remains while being the part of the second flap 12 not covered by the first flap 11. A coat of adhesive is applied to part of the tab 16 and is entirely covered with a protection strip 17 made of siliconized paper. After the manual removal of the protection strip 17, the tab 16 can be folded onto the first flap 11 in order to be bonded and thus close the envelope, as shown in [FIG. 3]. [FIG. 4] shows the bag 1 in a manufacturing step before the folding of the first flap 11 onto the second flap 12.

[0079] In an accomplishment mode, the bag l differs from that of the first accomplishment mode in that the hem 15 is linked to a central part 110 of the flap 11, 12 by means of a cheek 181 folded onto the central part 110, in such a way that a bellows 18 is formed by two cheeks 181 linked by the hems 15 stuck together.

[0080] In a third accomplishment mode for making bag 1, shown in FIGS. 6 to 8, the flaps 11, 12 are formed by superposing a first strip 1a, a first reinforcement panel 19a, a second reinforcement panel 19b and a second strip 1b. The first reinforcement panel 19a is not as wide as the first strip 1a and the second reinforcement panel 19b is not as wide as the first reinforcement panel 19a. The second strip 1b is not as wide as the first strip 1a but wider than the first reinforcement panel 19a. In the transverse sectional view in [FIG. 7] it can be seen that the first strip 1a comprises some adhesive on the internal face 14 in such a way that the first reinforcement panel 19a is bonded to it. Likewise, the second strip 1b comprises some adhesive on the internal face 14 in such a way that it is bonded to the second reinforcement panel 19b, to the first reinforcement panel 19a on the edges not covered by the second reinforcement panel 19b, and on the first strip 1a between the hem 15 and the edge of the first reinforcement panel 19a. In the longitudinal sectional view, the reinforcement panels 19a, 19b are interrupted at the level of the folding crease 13. Furthermore, the reinforcement panels 19a, 19b do not extend over the tab 16 which is thus formed from the superposing of the two strips 1a, 1b only.

[0081] In a fourth accomplishment mode, shown in [FIG. 9], the bag 1 differs from that of the third accomplishment mode in that the hem 15 is linked to a central part 110 of the flap by means of a cheek 181 folded onto the central part 110, in such a way that a bellows 18 is formed by two cheeks 181 linked by the hems 15 bonded together.

[0082] A machine 2 as per a first accomplishment mode of the invention enabling the manufacture of bags is shown schematically in [FIG. 10]. The machine 2 comprises: [0083] a first unwinding means 201 for unreeling the continuous strip of flexible material in a longitudinal direction; [0084] a first means of adhesive application 211 for making a first application of adhesive at least on the first strip 1a, [0085] a feed means 22 for supplying the reinforcement layer, [0086] a second cutting means 220 for cutting the reinforcement layer and thus obtain a reinforcement panel 19a, 19b, [0087] a second unwinding means 202 for unreeling the second strip 1b of flexible material, [0088] an application means 23 for applying a coat of adhesive and a protection strip 17 on the coat of adhesive on the second strip 1b at regular intervals, [0089] a second means of adhesive application 212 to make a second adhesive application on the second strip 1b, [0090] an intake means 24 also configured to assemble the second strip 1b and the first strip 1a with the reinforcement panels 19a, 19b between them on the internal face 14 of the first strip 1a, [0091] a hemmer 251 for each edge to form a hem 15 on each edge of the first strip upstream of the intake means 24, [0092] a transport means 26 for guiding the assembly of the strips downstream of the intake means 24; [0093] an application means 27 for applying adhesive to the hems 15 over at least one length of the first or second flap 12 on a seam face 150, [0094] a first cutting means 28 for cutting the strip with a transversal cut to form a section forming the bag 1 at the end of the operations; [0095] an assembly means, for bringing the first and second flaps 11, 12 together along the edges, made by folding means 29 to form a folding of the first strip 1a along a transversal folding crease 13, to fold the first flap 11 onto the second flap 12 against an internal face 14 of the first strip 1a, and to bring the hem 15 against hem 15 for each edge by the seam face 150 in such a way as to obtain the bonding together of the hems 15 to bring the first and second flaps 11, 12 together along the edges, [0096] a stacking means, not shown, to stack the bags downstream of the folding means 29.

[0097] Optionally, the machine comprises another hemmer 252 for making a hem on the edges of the second strip 1b in the case where the second strip is wider than the first strip and where the hems are only supported by the second strip 1b.

[0098] The first and second adhesive application means 211, 212 are, for example, flexographic rollers making it possible to apply adhesive according to a predetermined pattern. The adhesive is applied on the internal face 14 of the strip; that is to say on the face opposite the other strip after assembly.

[0099] The intake means 24 is made with a pair of contra-rotary rollers 241 driven by a motor, not shown. They apply a pressure to the strips 1a, 1b to obtain bonding between them and to the reinforcement panels 19a, 19b.

[0100] The feed means 22 also comprises intake means 221 for bringing together two reinforcement strips, then the second cutting means 220 for cutting the strips assembled into panels 19a, 19b, as detailed below.

[0101] The transport means 26 should preferably be means functioning by suction so as not apply any forces through the thickness of the assembly.

[0102] The application means 27 shall, for example, be nozzles injecting adhesive intermittently.

[0103] The first cutting means 28 and the folding means 29 are conventional and are not described here. The various parts are driven in rotation either by the same motor and synchronous mechanical transmissions such as cog belts or gears, or by several individual electronically synchronised motors, or a combination of the two solutions.

[0104] A machine 2 conform to a second accomplishment mode, shown in [FIG. 11], is provided to make bags with bellows 18. It differs from that of the first accomplishment mode in that a cheek formation station 30 is also provided downstream of the intake means 24 and configured to also form a cheek 181 on each edge of the first strip 1a or of the superposing of the strips 1a, 1b.

[0105] FIG. 12 shows the first strip 1a of flexible material seen from the top, therefore presenting its internal face 14, from its unreeling on the right to the formation of the bag 1 on the left. The upper part above a middle centreline A represents the version of a bag l as per the second accomplishment mode, that is to say with bellows 18, whereas the lower part shows the version of the bag 1 as per the first accomplishment mode, that is to say without bellows. For the first accomplishment mode, the width of the strip is subdivided into a central part 110 and a hem area 15. The hemmer 251 comprises an application means, not shown, which applies adhesive at intervals on the edge of the hem area 15 over the length represented by the dashed line 152 corresponding to the first flap 11, then, in the hemmer 251, the hem area 15 is turned over against the central part 110 on the internal face 14. Thus, the hem is bonded on its internal face at intervals, along the area symbolized by the line 152. The application means may for example be

[0106] In the second accomplishment mode, the width of the strip is subdivided into a central part 110, a cheek 181 and a hem area 15. By passing through the hemmer's application means, not shown, adhesive is applied at intervals on the edge of the hem area 15 over the length represented by the dashed lines 153 corresponding to the first flap 11, on the external face, opposite the internal face 14. The hem 15 is formed when passing through the hemmer 251 by folding over onto the external face and is stuck onto the length extending from the future cutting 111 of the section to the future folding crease 13, along what will be the first flap 11. Downstream of the intake means 24, the first strip 1a passes through the cheek formation station 181 in which the cheeks 181 are folded against the internal face 14 of the first strip 1a. The hem 15 becomes visible again above the first strip 1a, when looking at the internal face 14. After folding the cheek 181 against the internal face 14, the latter extends between the hem 15 and a central part 110 of the strip, in such a way that a stack is formed with, in the following order, the central part 110, the cheek 181 and the hem 15.

[0107] In both accomplishment modes, the visible face of the hems 15, also called seam face 150, is coated with adhesive over the same lengths on both sides of the future folding crease 13, then the first strip 1a is cut by the first cutting means 28 into sections, at the level of the cutting line 111. The sections are transferred to the folding means 29 which forms the folding crease 13 and folds the first flap 11 onto the second flap 12. The hems 15 of the first flap 11 then adhere to the hems 15 of the second flap 12 and the bag 1 is formed, as shown in [FIG. 1] for the bag 1 without bellows, or [FIG. 5] for the bag 1 with bellows 18.

[0108] [FIG. 13], constructed like [FIG. 12], details the assembly of the strips when the bags are made with reinforcement panels, here with two thicknesses. The intake means 221 of the feed means 22 takes two layers of reinforcement and superposes them, the layer on the first strip 1a side being wider than the other one. The second cutting means 220 cuts a first part of the reinforcement panel 19a1, 19b1 which will extend over the first flap 11, then a second part of the reinforcement panel 19a2, 19b2 which will extend over the second flap 12. A small interval is created between the first and second parts of the reinforcement panel in order to allow the easy creation of the folding crease 13. The intake means 221 of the feed means 22 slows down the reinforcement strip feed to allow the creation of an interval on the second flap 12 between the second part of the panel and the first part of the next section, this interval being the space for tab 16. The reinforcement panels only extend over the central part 110 of the first strip 1a, and therefore not over the cheeks 181 in the case of a bag 1 with bellows 18, even if this is technically possible for flexible panels.

[0109] The invention is not limited to the accomplishment modes which are described as examples only. The protection strip 17 and the coat of adhesive that it protects are optional or could take various forms.