FLEXIBLE BAG HAVING A CONVERTIBLE BOTTOM, METHOD AND MACHINE FOR MANUFACTURING SAME

Abstract

A bag made of flexible material has a first and a second segment having cheeks along their selvages, the cheeks being joined together so as to form two gussets joining the segments together, one end of the bag perpendicular to the selvages being closed. The bag has a system of at least one reinforcing panel extending over a central part of the segments, between the gussets, each segment having a fold marking line, one opposite the other, in order to delimit a bottom at the closed end. Method and machine for manufacturing such a bag.

Claims

1. A bag made of a flexible material comprising a first and a second flap comprising cheeks along their edges, the cheeks being brought together in such a way as to form two bellows bringing the flaps together, one end of the bag perpendicular to the edges being closed, the bag further comprising a system with at least one reinforcement panel extending over a central part of the flaps, between the bellows, 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.

2. The bag according to claim 1, in which each flap comprises a crease marking line one opposite the other to delimit a bottom at the closed end.

3. The bag according to claim 1, in which the system with at least one panel comprises a first and a second panel extending respectively over the first and second flaps, the panels being separated at the closed end.

4. The bag according to claim 3, in which the first and second panel only extend beyond the marking lines with respect to the bottom.

5. The bag according to claim 1, in which the system with at least one panel comprises a third panel extending over the first and second flaps.

6. The bag according to claim 3, in which the system with at least one panel only extends short of the marking lines on the bottom side.

7. The bag according to claim 3, in which the panel system extends on both sides of the marking lines, the marking lines also being formed on the system with at least one panel.

8. The bag according to claim 1, wherein each bellows cheek is bonded against the adjacent flap according to a corner area extending to the corner of the central part of the flap between the closed end and the marking line on said flap.

9. The bag according to claim 8, in which the corner area is in the form of a right triangle whose right angle is a corner of the central part of the flap.

10. The bag according to claim 1, in which a second strip of flexible material is bonded to the inside of the bag and covers at least the system with at least one reinforcement panel.

11. A process for manufacturing a bag made of flexible material whereby: a first strip of flexible material is unreeled as a continuous sheet using a first unwinding means in a longitudinal direction, a fold is made using folding means 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 using a first cutting means 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 using a cheek formation station, a cheek and a hem are formed on each edge of the first layer before folding and adhesive is applied to the hems at least over one length of the first or second flap on one seam face using application means, the folding bringing hem against hem for each edge 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 by means of bellows formed by the cheeks, at least one reinforcement layer is unreeled using feed means, the reinforcement layer is cut using a second cutting means to obtain a system with at least one reinforcement panel, a first application of adhesive is made using the first adhesive application means 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.

12. The process according to claim 11 whereby, using a push-back means, a crease marking line is made on each flap on both sides of the folding crease in such a way that after folding, each marking line is opposite the other one.

13. The process according to claim 11 whereby a second strip of flexible material is unreeled using the second unwinding means, a second application of adhesive is done using the second adhesive application means, and the second strip and the first strip are brought together on the internal face of the first strip so that the second strip at least covers the system with at least one reinforcement panel and is bonded to it.

14. The process according to claim 13 whereby the width of the first and second strips are different in such a way that the hems extend from just one of said strips.

15. The process according to claim 13 whereby the width of the second strip is identical to that of the first strip.

16. The process according to claim 11 whereby the system with at least one reinforcement panel comprises a single panel which extends over the first and second flaps.

17. The process according to claim 11 whereby, to form the system with at least one reinforcement panel, two reinforcement panels are successively cut and placed, one on the first flap and the other on the second flap leaving a gap between them at the level of the folding crease.

18. The process according to claim 11 whereby, using a third means of adhesive application downstream of the intake means and upstream of the cheek formation station, adhesive is applied to each bellows cheek or to the central part of the flaps in the corner areas that extend, after formation of the bag, to the corners of the central part of the flaps between the folding crease and the marking lines on said flaps.

19. The process according to claim 11 whereby a hem is also bonded to the face opposite the seam face along just one of the elements among the first and second flaps.

20. A machine for manufacturing a bag with a flexible material 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 folding the first strip along a transversal folding crease and fold 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 before or after the folding of the flaps one on the other, the section forming the bag at the end of the operations; wherein the machine also comprises a cheek formation station to form a cheek and a hem on each edge of the first layer before folding, 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 folding means being configured to bring hem against hem for each edge 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 by means of the bellows formed by the cheeks, feed means for unreeling at least one reinforcement layer, a second cutting means for cutting the reinforcement layer to obtain a system with at least one reinforcement panel, a first adhesive application means for making a first adhesive application 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 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 first adhesive application, in such a way that the system with at least one panel is located between the first and second flaps.

21. The machine according to claim 20, wherein the machine also comprises a push-back means for making a crease marking line on each flap on each side of the folding crease in such a way that after folding, each marking line is opposite the other one.

22. The machine according to claim 20, wherein the machine further comprises a third means of adhesive application downstream of the intake means and upstream of the cheek formation station to apply adhesive on each bellows cheek or on the central part of the flaps in the corner areas which, after the formation of the bag, extend to the corners of the central part of the flaps between the folding crease and the marking lines on said flaps.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0055] 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:

[0056] FIG. 1 is a perspective view of a bag as per a first invention accomplishment mode, in the folded position at machine output;

[0057] FIG. 2 is a perspective view of the bag in [FIG. 1] after deployment and before filling;

[0058] FIG. 3 is an end view seen from the open end of the bag in [FIG. 2];

[0059] FIG. 4 is a sectional view as per plane IV of [FIG. 1];

[0060] FIG. 5 is a view similar to [FIG. 2] of a bag as per a variant;

[0061] FIG. 6 is a longitudinal sectional view of the bag in [FIG. 4], in the folded position;

[0062] FIG. 7 is a view of the bag in [FIG. 4] in an intermediate manufacturing step;

[0063] FIG. 8 is a schematic view of a machine for manufacturing bags as per [FIG. 1];

[0064] FIG. 9 is a plan view of an intermediate bag manufacturing phase including, in particular, the cheek formation phase;

[0065] FIG. 10 is a plan view of an intermediate bag manufacturing phase, as per a first manufacturing mode;

[0066] FIG. 11 is a plan view of an intermediate bag manufacturing phase, as per a second manufacturing mode;

[0067] FIG. 12 is a plan view of an intermediate bag manufacturing phase, as per a third manufacturing mode;

[0068] FIG. 13 is a plan view of an intermediate bag manufacturing phase, as per a fourth manufacturing mode;

[0069] FIG. 14 is a plan view of an intermediate bag manufacturing phase, as per a fifth manufacturing mode;

[0070] FIG. 15 is a plan view of a manufacturing step similar to [FIG. 9] showing an additional application of adhesive.

DETAILED DESCRIPTION

[0071] 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 a 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 linked to a central part 110 of the flap 11, 12 by means of a cheek 181 folded onto the central part 110. Furthermore, the hem 15 is bonded to cheek 181 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, in such a way that a bellows 18 is formed by two cheeks 181 linked by the hems 15 stuck together. Each flap 11, 12 comprises a marking line 17 at a distance from the folding crease 13 more or less equal to the width of the cheeks 181, excluding the hem.

[0072] The bag 1, shown in the deployed position in [FIG. 2], can be stood on a bottom delimited between the marking lines 17.

[0073] As shown in the transverse sectional view of [FIG. 4], flaps 11, 12 are formed by superposing a first strip 1a, of a system of reinforcement panels 19, comprising a first reinforcement panel 19a and a second reinforcement panel 19b, and a second strip 1b. The first and second panels 19a, 19b are divided into two parts 19a1, 19a2, 19b1, 19b2 on each side of the folding crease 13. The first reinforcement panel 19a is narrower than the central part 110 of the first strip 1a and the second reinforcement panel 19b is narrower than the first reinforcement panel 19a. The second strip 1b is narrower than the first strip 1a but wider than the first reinforcement panel 19a. In [FIG. 4], it can be seen that the first strip 1a comprises adhesive on the internal face in such a way that the first reinforcement panel 19a is stuck to it. Likewise, the second strip 1b comprises adhesive on the internal face in such a way that it is stuck 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.

[0074] In a variant shown in FIGS. 5 to 7, the first flap 11 of the bag 1 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. In the longitudinal sectional view of [FIG. 4], the reinforcement panels 19a, 19b are interrupted at the level of the folding crease 13 and are therefore divided into two parts 19a1, 19a2, respectively 19b1, 19b2. Furthermore, the reinforcement panels 19a, 19b do not extend onto tab 16 which is thus formed by the superposing of the two strips 1a, 1b only.

[0075] FIG. 7 shows the bag 1 of [FIG. 5] in a manufacturing step before the folding of the first flap 11 onto the second flap 12. The folding crease 13 serves as the pivoting axis of the first flap 11 onto the second flap 12.

[0076] A machine 2 as per a first accomplishment mode of the invention enabling the manufacture of bags is shown schematically in [FIG. 8]. The machine 2 comprises: [0077] a first unwinding means 201 for unreeling the continuous strip of flexible material in a longitudinal direction; [0078] a first means of adhesive application 211 for making a first application of adhesive at least on the first strip 1a, [0079] a feed means 22 for supplying the reinforcement layer, [0080] a second cutting means 220 for cutting the reinforcement layer and thus obtain a reinforcement panel 19a, 19b, [0081] a second unwinding means 202 for unreeling the second strip 1b of flexible material, [0082] a second means of adhesive application 212 to make a second adhesive application on the second strip 1b, [0083] 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, [0084] a hemmer 251 for each edge to form a hem 15 on each edge of the first strip 1a upstream of the intake means 24, [0085] a cheek formation station 30 downstream of the intake means 24 and also configured to form a cheek 181 on each edge of one of the strips 1a, 1b or of the superposing of the strips 1a, 1b, [0086] a push-back means 31 downstream of the cheek formation station 30 to mark a crease marking line 17 on each flap on both sides of the folding crease 13, [0087] a transport means 26 for guiding the assembly of the layers downstream of the push-back means 31; [0088] an application means 27 for applying adhesive to the hems 15 over at least one length of the first or second flap 11, 12 on a seam face 150, [0089] a first cutting means 28 for cutting the strip with a transversal cut to form a section T forming the bag 1 at the end of the operations; [0090] a folding means 29 for forming a fold 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, in order 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 of the hems 15 to each other to bring the first and second flaps 11, 12 together along the edges, [0091] a stacking means, not shown, to stack the bags downstream of the folding means 29.

[0092] Optionally, the machine 2 may comprise a third means of adhesive application 33, downstream of the intake means 24 and upstream of the cheek formation station 31, to apply adhesive to each bellows cheek 181 or to the central part 110 of the flaps in the corner areas 10 that extend, after bag formation, to the corners of the central part 110 of the flaps between the folding crease 13 and the marking lines 17 on said flaps 11, 12

[0093] Optionally, the machine comprises another hemmer 252 for making a hem 15 on the edges of the second strip 1b in the case where the second strip 1b is wider than the first strip 1a and where the hems 15 are only supported by the second strip 1b.

[0094] The first, second and third adhesive application means 211, 212, 33 are, for example, flexographic rollers making it possible to apply adhesive according to a predetermined pattern. For the first and second application means, 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. The third application means 33 is placed downstream of the intake means, because the exposed adhesive would make the adhesive-coated surface stick to the rollers of the intake means 33. However, it could be considered that the third adhesive application means 33 could be placed upstream of the intake means 33 if the latter comprises circular grooves allowing the adhesive-coated areas 10 to pass.

[0095] 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.

[0096] The feed means 22 also comprises intake means 221 for bringing together two reinforcement strips, then the second cutting means 220 for cutting the reinforcement strips assembled into panels 19a, 19b, as detailed below.

[0097] The transport means 26 should preferably be means functioning by suction so as not apply any forces through the thickness of the assembly.

[0098] The application means 27 shall, for example, be nozzles injecting adhesive intermittently.

[0099] The first cutting means 28 and the folding means 29 are conventional and are not described here. The machine's 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.

[0100] FIG. 9 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, as shown by arrow F. The second strip 1b is not shown to avoid overloading the illustration. The width of the strip 1a is subdivided into a central part 110, two cheeks 181 and two hem areas 15 on each side of the central part 110. By passing through the first adhesive application means 211, adhesive is deposited at intervals on the edge of the hem area 15 over the length represented by the dashed line 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 onto the external face and is bonded 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.

[0101] 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 gap is created between the first and second parts of the system of reinforcement panels 19 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 a gap on the second flap 12 between the second part of the panel and the first part of the next section. The reinforcement panels 19 only extend over the central part 110 of the first strip 1a, and therefore not over the cheeks 181. In the first accomplishment mode, which is presented here, each part of the reinforcement panel 19 extends between the future folding crease 13 and a future marking line 17. All of the first strip 1a is covered by the second strip 1b over the panel system 19 to form an assembly of strips after passing through the intake means 24. The application of adhesive to the second strip 1b allows it to be bonded to the narrowest reinforcement panel, in the areas of the reinforcement panel not covered by the previous one and to the first strip 1a.

[0102] Downstream of the intake means 24, the assembly of strips passes through the cheek formation station 30 in which the cheeks 181 are folded against the second strip 1b. The hem 15 becomes visible again from the top, when looking at the internal face 14 of the bag. 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.

[0103] 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 by the application means 27, then the assembly of strips is cut by the first cutting means 28 into sections T, at the level of the cutting line 111. The sections T 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].

[0104] FIG. 10 shows the assembly of strips after the formation of the cheeks 181. In particular, we have shown the two parts of the reinforcement panels 19a1, 19b1, 19a2, 19b2 on both sides of the future folding crease 13. The cut edge of the first flap 11 is located after folding at the level of the dotted line 112 and leaves a tab 16 on the second flap 12.

[0105] FIG. 11 is a similar view to that of [FIG. 10] as per a second accomplishment mode. It differs from the first accomplishment mode in that the two parts of the panels 19a1, 19b1, 19a2, 19b2 are longer than in the first accomplishment mode and extend beyond the marking lines 17.

[0106] FIG. 12 is a similar view to that of [FIG. 10] as per a third accomplishment mode. It differs from the first accomplishment mode in that the two parts of the panels 19a1, 19b1, 19a2, 19b2 extend between the marking lines 17 and the first edge of the first panel or to the mark 112.

[0107] FIG. 13 is a similar view to that of [FIG. 10] as per a fourth accomplishment mode. It differs from the first accomplishment mode in that the two parts of the panels 19a1.sup.3, 19b1.sup.3, 19a2.sup.3, 19b2.sup.3 extend beyond the marking lines 17 from the future folding crease 13 to the edge of the first flap 11 and to the mark 112.

[0108] FIG. 14 is a similar view to that of [FIG. 10] as per a fifth accomplishment mode. It differs from the first accomplishment mode in that the panels 19a.sup.4, 19b.sup.4 extend over the two flaps 11, 12 without any interruption at the level of the folding crease 13 and beyond the marking lines 17 from the edge of the first flap 11 and to the mark 112.

[0109] FIG. 15 is a similar view to that of [FIG. 9] in which the panel system is not shown. After assembly of the first strip 1a, the panel system 19 and the second strip 1b if there is one, therefore downstream of the intake means 24 and upstream of the cheek formation station 30, the third adhesive application means 33 is used to apply adhesive to each bellows cheek 181 in four corner areas 10. The corner areas 10 are located symmetrically to the future folding crease 13. They have an isosceles right triangle shape with the right angle close to the join between the future folding crease 13 and the future crease between the central part 110 and the cheek 181. The corner areas 10 extend as far as the marking lines. After passing through the cheek formation station, the corner areas 10 are folded with the cheeks against the central part 110 of the assembly to obtain bonding in these areas. After the formation of the bag, the corner areas 10 extend to the corners of the central part 110 of the flaps between the folding crease 13 and onto said flaps 11, 12.

[0110] When opening the bag, by separating the flaps 11, 12 and deploying the bellows 18, the bonded part of the cheeks remains linked to the central part 110 between the marking lines 17 on the corner areas 10, which facilitates the formation of the rectangular-shaped bottom.

[0111] In a variant, not shown, the corner areas 10 along the same cheek on both sides of the folding crease 13 can be brought together.