EP0549500A1 - Sealed, washable sack, manufacturing method and machine to form its base - Google Patents

Abstract

The present invention relates to a waterproof and washable packaging bag, its corresponding manufacturing process and the machine for shaping its bottom. Waterproof and washable packaging bag, without gusset, made from a complex whose internal face is heat-sealable, characterized in that it comprises a waterproof rectangular bottom (2), having no interior recess, essentially consisting of two lateral tabs (3, 3 ') cut from the tube (4) constituting the body of the bag folded transversely inwards and assembled, by welding, on the one hand, to each other at their free ends, and, on the other hand, along their longitudinal edges, with the bases (7) of the two median tabs (6, 6 '), also cut in the tube (4), the latter being folded down and glued to said lateral tabs (3, 3 ') assembled, overlapping at least partially. <IMAGE> <IMAGE>

Description

The present invention relates to the field of packaging, more particularly bags of large waterproof and washable capacity, and relates to a waterproof and washable packaging bag, its manufacturing process and a machine for shaping its bottom.

The currently known waterproof packaging bags generally consist of an independent inner sheath and one or more outer layers of reinforcement and of printing support, the assembly being folded and glued at the bottom and welded at the level of the opening, after filling, in order to make it waterproof. However, due to the various folding operations at the bottom, recesses which are not accessible, and therefore cannot be drained or washed, are formed at this level. In addition, said bag can not be produced from a complex in one piece, and does not have, after filling, a rectangular bottom, which leads to awkward palletization. Furthermore, in order to set up a print at the bottom, it is necessary to laminate an additional back strip comprising said print.

Also known are sealed packaging bags with pinched bottom and bellows, also called "Pinch", which overcomes some of the above drawbacks. Indeed, these bellows packaging bags are provided with rectangular bottoms, devoid of interior recesses.

However, the presence of the bellows, at the opening of the bags, requires the use of a machine specially adapted for filling and sealing by welding. In addition, the change in the number of layers at the opening and the possible presence of wrapped material between the bellows, when said opening is pinched in order to achieve the welding of sealing, lead to the appearance of privileged break points at the level of said weld, which could compromise the tightness of said packaging bag.

The problem posed by the invention therefore consists in making a waterproof and washable packaging bag, without bellows, having no inaccessible interior recess and the bottom of which has a rectangular shape. In addition, said packaging bag must be able to be manufactured from a complex in one piece or obtained by laminating several layers and will not require any additional backing strip for the establishment, at its bottom, suitable printing.

This problem is precisely solved by the invention, thanks to the waterproof and washable packaging bag, without gusset, produced from a complex whose internal face is heat-sealable, characterized in that it comprises a waterproof rectangular bottom, does not having no interior recess, essentially constituted by two lateral tabs cut from the tube constituting the body of the bag, folded transversely inward and assembled, by welding, on the one hand, between them at their free ends, and, d on the other hand, along their longitudinal edges, with the bases of the two median tabs, also cut from the tube, the latter being folded down and glued to said assembled lateral tabs, overlapping at least partially.

The subject of the invention is also a method of manufacturing a said packaging bag, characterized in that it essentially consists in producing, from a strip of a complex, the internal face of which is heat-sealable, open tubes comprising at one of their ends two lateral tabs and two median tabs, then, after grooving, to fold transversely the lateral tabs and to assemble them by thermal welding at their free ends, to assemble by thermal welding said tabs lateral at their longitudinal edges, with the internal face of the tubes, along the bases of the tongues medians, and, finally, successively folding down the median tabs after cutting to length and gluing, against said assembled lateral tabs.

Finally, the invention also relates to a machine for shaping the bottom of the packaging bag described above, implementing, at least partially, the abovementioned method, characterized in that it is mainly constituted by a series of workstations shaping, namely, a device for grooving by crushing, a device for spacing the bottom of the tube, for folding the lateral tabs and for assembling the latter by thermal welding, a device for thermal welding of the longitudinal edges of the lateral tabs, a device for cutting out the middle tabs and a device for gluing and folding down the middle tabs, the packaging bag being formed is transported from one shaping station to the next by means of drive belts.

• les figures 1A à 1E représentent de manière schématique les différentes étapes de la fabrication du sac d'emballage conforme à l'invention,
• les figures 2 à 6 sont des vues en plan des dispositifs faisant partie de la machine conforme à l'invention, et,
• les figures 7 à 9 sont des vues en élévation frontale suivant F des dispositifs représentés respectivement aux figures 2, 4 et 5.

The invention will be better understood from the description below, which relates to the preferred embodiment, given by way of nonlimiting example, and explained with reference to the appended schematic drawings, in which:

• FIGS. 1A to 1E schematically represent the different stages of the production of the packaging bag according to the invention,
• FIGS. 2 to 6 are plan views of the devices forming part of the machine according to the invention, and,
• FIGS. 7 to 9 are front elevation views along F of the devices shown in FIGS. 2, 4 and 5 respectively.

According to the invention, the packaging bag has a sealed rectangular bottom 2, having no interior recess, essentially constituted by two lateral tabs 3, 3 ′ cut from the tube 4 constituting the body of the bag 1, folded transversely towards the interior and assembled, by welding, on the one hand, between them at their free ends, and, on the other hand, along their longitudinal edges 5, with the bases 7 of the two median tabs 6, 6 ', also cut from the tube 4, the latter being folded down and glued to said side tabs 3, 3' assembled, overlapping at least partially (Fig. 1A to 1E).

The bottom 2, made watertight by the assembly of the lateral tabs 3, 3 'therebetween as well as with the internal wall of the complex at the bases 7 of the two middle tabs 6, 6', is thus structurally reinforced by the lamination of the latter on the outer face of the lateral tabs 3, 3 '. The folding is carried out in such a way that the fold lines, at the level of the bases 7 of the tabs, medians 6, 6 ′, coincide with the inner edges 10 of the welding strips 11 between the lateral tabs 3, 3 'and medians 6 , 6 '.

Thus, the assembly areas at the bottom 2 of said packaging bag 1, are flush inside the latter, and, therefore, no non-washable corner, produced by parts of the packaging bag 1 pinched one against the other and / or folded, does not appear at said bottom 2 when said packaging bag 1 is deployed.

According to a first alternative embodiment of the invention, the packaging bag 1 is composed of a coextruded complex in one piece, the internal face of which is covered with a heat-sealable material, preferably polyethylene, and the face of which external consists of a non-heat-sealable printing medium such as, for example, paper, said complex possibly comprising, where appropriate, intermediate reinforcing layers and / or having specific barrier properties, such as, in particular, a layer made of aluminum, a tear-resistant layer or the like.

The outer layer supporting the printing may preferably consist either of kraft-type paper or of treated paper, depending on the complexity and dimensions of the details of the printing to be affixed.

In accordance with a second alternative embodiment of the invention, shown in FIG. 1A of the accompanying drawings, the packaging bag 1 is constituted by a complex obtained by laminating several layers having specific properties, including in particular an inner layer in a heat-sealable material such as, for example, polyethylene, and a non-heat-sealable outer layer capable of withstanding printing, such as, for example, paper, the laminating being carried out continuously at the level of the cutting zone of the transverse tabs 3, 3 'and medians 6, 6' and at the level of the zone proximal to the opening 8 of said packaging bag 1.

As shown in FIG. 1E of the appended drawings, the upper middle tab 6, as well as, optionally, the uncovered part of the lower middle tab 6 ′, has an impression 9 of an informative and / or decorative nature.

The invention also relates to a method of manufacturing a packaging bag 1 essentially consisting in producing, from a strip of a complex, the internal face of which is heat-sealable, open tubes 4 comprising at the one of their ends two lateral tabs 3, 3 'and two median tabs 6, 6' then, after grooving, to fold the lateral tabs 3,3 'transversely and to assemble them by thermal welding at their free ends, to be assembled by thermal welding said lateral tabs 3, 3 'at their longitudinal edges 5, with the internal face of the tubes 4, along the bases 7 of the middle tabs 6, 6', and, finally, successively folding down the middle tabs 6 , 6 'after cutting to length and gluing, against said assembled side tabs 3.3' (Fig. 1A to 1E).

As shown more particularly in FIG. 1A of the appended drawings, the production of the tubes 4 consists in folding, flat, the two longitudinal edges of a strip of a heat-sealable complex towards each other, so as to obtain a hollow pipe, to be assembled by longitudinal thermal welding of the faces internal overlap zones 12 of the folded edges, to cut the continuous hollow pipe obtained into tubes 4 of predetermined length, depending on the size of the packaging bag 1 to be produced, and, finally, to cut two lateral tabs 3, 3 ' and two median tabs 6, 6 ′ by means of two rectilinear incisions 13, symmetrical with respect to the longitudinal axis of the flattened tubes 4 and extending from one of the open ends of said tubes 4.

The shaping of the bottoms 2 of the packaging bags 1, from tubes 4 comprising two lateral tabs 3, 3 'and two median tabs 6, 6', consists in providing grooves 14 at an angle extending from the folding edges 15 , 15 'of the flattened tube at the ends of the rectilinear incisions 13, then to spread the bottom of the tube 4 and to fold the lateral tabs 3, 3' towards each other, by deforming the tube 4 along the grooves 14 previously crushed , then to assemble the free ends of the lateral tabs 3, 3 'by thermal welding of their overlap zones 16, to assemble by thermal welding the longitudinal edges 5 of the lateral tabs 3, 3' folded with the internal face of the tube 4 at the level bases 7 of the middle tabs 6, 6 ', to cut the middle tabs 5, 5' to given lengths, depending on the dimensions of the bottom 2 desired, to coat said middle tabs 6, 6 'with an adhesive, and, finally , fold up succe ssively the middle tabs 6, 6 'at their bases 7 along fold lines determined by the inner edges 10 of the assembly areas 11 of the longitudinal edges 5 of the side tabs 3, 3', by folding them over the latter with at least partial mutual recovery (Fig. 1A to 1E).

Finally, the invention also relates to a machine for shaping the bottom 2 of the packaging bag 1, shown in Figures 2 to 9 of the accompanying drawings and mainly consisting of a series of shaping stations 17 to 21, namely, a device 17 for grooving by crushing, a device 18 for spacing the bottom of the tube 4, for folding the lateral tabs 3, 3 ′ and for assembling the latter by thermal welding, a device 19 for thermal welding of the longitudinal edges 5 of the lateral tabs 3, 3 ', a device 20 for cutting the middle tabs 6, 6' and a device 21 for gluing and folding down the middle tabs 6, 6 'the packaging bag 1 being formed being transported from a given shaping station 17, 18, 19, or 20 to the next one 18, 19, 20 or 21 by means of drive belts 22.

As shown in Figures 2 and 7, the grooving device 17 is advantageously in the form of a press comprising a fixed plate 24 supporting the tube 4 and a plate 25 movable vertically by means of at least one cylinder 26 and comprising the ribs 27 for crushing the grooves 14.

The device 18 can be composed, for example, on the one hand, of two plates 28 for gripping and spacing the central tongues 6,6 ′, pivotally mounted on axes of rotation 29 and controlled by jacks 30, on the other hand, two electrodes 31, which can be moved towards one another, from the folding edges 15, 15 ′ of the tube 4 in position, for folding the lateral tabs 3, 3 ′ along the grooves 14 and their assembly by thermal welding at the overlap areas 16 of their free ends and, finally, a sheet 32 ensuring the folding of the welding strip obtained (Figure 3).

The thermal welding device 19, shown in Figures 4 and 8 of the accompanying drawings, consists mainly of a retractable support 33, in the form of two movable bars 34, 34 ′, which can be arranged opposite the bases 7 middle tabs 6, 6 ′, and in a thermal welding block 35 comprising two elongated electrodes 36 and which can be moved, by jacks 37, in the direction of the bottom 2 of the packaging bag 1, in order to carry out the assembly, by thermal welding, longitudinal edges 5 of the lateral tabs 3, 3 ′ with the internal face of the body of the packaging bag 1 at the level of the bases 7 of the median tabs 6, 6 ′, the latter being in the separated position (Figure 8) .

As shown in Figures 5 and 9 of the accompanying drawings, the cutting device 20 is composed of two pivoting blades 38 actuated by corresponding cylinders 39, making it possible to cut each middle tab 6 or 6 'to its respective length, namely a small length for the lower middle tab 6 'and a greater length for the upper middle tab 6, so that they extend, after folding, over the entire width of the bottom 2 with a slight mutual overlap.

Finally, the device 21 for gluing and folding down the middle tabs 6, 6 ′ consists, on the other hand, of an adhesive application block 40 provided with several dispensing orifices 41 and, on the other hand part, by folding guides 42, 42 'respectively for the upper middle tab 6 and for the lower middle tab 6', the gluing and the folding being effected by the movement of movement of the packaging bag 1 driven by the bands drive 22. So that the folding and lowering of the lower middle strip 6 'takes place before that of the upper middle strip 6, the guide 42' extends further in the direction opposite to the movement of the bags of packing 1 as guide 42 (Figure 6).

The machine according to the invention also includes devices for controlling the pressure, the temperature and the welding times, as well as various indicator lights and display dials making it possible to monitor the progress of the shaping of the bottom 2.

The transport of the packaging bags 1 during manufacture from a shaping station given to the next is carried out discontinuously, possibly under the control of a programmable controller.

As shown in the description above, the packaging bag according to the invention has a relatively simple structure at its bottom 2, the latter nevertheless being very resistant, and perfectly waterproof, and having no non-washable corners. he it also follows that said packaging bag 1 can be produced in a limited number of shaping operations.

In addition, the bottom 2 of the bag according to the invention is completely gas tight.

Indeed, the welding of the two lateral tabs 3, 3 'is carried out by applying one against the other and by joining together (by application of heat and pressure), each time, the heat-sealable layers of the portions to be assembled , namely, on the one hand, the free ends of said lateral tabs 3, 3 'and, on the other hand, the longitudinal edges 5 of said tabs 3, 3' with the bases of the two middle tabs 6, 6 '.

In addition, the layers of complex (for example: outer layer of paper and inner layer of heat-sealable material) to be assembled by welding are always two in number and therefore have constant thicknesses to be assembled, making it possible to easily control the heat sealing operation and guarantee continuity and perfect sealing at the level of the welding area or line.

Of course, the invention is not limited to the embodiment described and shown in the accompanying drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements, or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (10)

Waterproof and washable packaging bag, without gusset, made from a complex whose internal face is heat-sealable, characterized in that it comprises a waterproof rectangular bottom (2), having no interior recess, essentially consisting of two lateral tabs (3, 3 ') cut from the tube (4) constituting the body of the bag (1), folded transversely inwards and assembled, by welding, on the one hand, between them at their free ends, and, on the other hand, along their longitudinal edges (5), with the bases (7) of the two median tabs (6, 6 '), also cut in the tube (4), the latter being folded down and glued on said side tabs (3, 3 ') assembled, overlapping at least partially. Packaging bag according to claim 1, characterized in that it is composed of a coextruded complex in one piece, the internal face of which is covered with a heat-sealable material, preferably polyethylene, and the external face of which consists in a non-heat-sealable printing medium such as, for example, paper, said complex possibly comprising, if necessary, intermediate layers of reinforcement and / or having specific barrier properties. Packaging bag according to claim 1, characterized in that it consists of a complex obtained by laminating several layers having specific properties, including in particular an inner layer of a heat-sealable material such as, for example, polyethylene, and a non-heat-sealable outer layer capable of withstanding printing, such as for example paper, the laminating being carried out continuously at the level of the cutting zone of the transverse (3, 3 ′) and middle (6, 6 ′) tabs and at the proximal region of the opening (8) of said packaging bag (1). Packaging bag according to any one of Claims 1 to 3, characterized in that the upper middle tab (6), as well as, optionally, the uncoated part of the lower middle tab (6 '), has a print ( 9) informative and / or decorative in nature. Method for manufacturing a packaging bag according to any one of Claims 1 to 4, characterized in that it consists essentially in producing, from a strip of a complex, the internal face of which is heat-sealable, open tubes (4) comprising at one of their ends two lateral tabs (3, 3 ') and two median tabs (6, 6'), then, after grooving, folding the lateral tabs (3,3 ' ) and to assemble them by thermal welding at their free ends, to assemble by thermal welding said lateral tabs (3, 3 ') at their longitudinal edges (5) with the internal face of the tubes (4), along bases (7) of the middle tabs (6, 6 '), and finally, successively folding down the middle tabs (6, 6'), after lengthening and coating, against said lateral tabs (3, 3 ') assemblies. Manufacturing method according to claim 5, characterized in that the production of the tubes (4) consists in folding, flat, the two longitudinal edges of a strip of a heat-sealable complex towards each other, so as to obtain a hollow pipe, to be assembled by longitudinal thermal welding the internal faces of the overlap zones (12) of the folded edges, to cut the continuous hollow pipe obtained into tubes (4) of predetermined length, depending on the size of the packaging bag (1) to make, and finally to cut two lateral tabs (3, 3 ') and two middle tabs (6, 6') by means of two rectilinear incisions 13 symmetrical with respect to the longitudinal axis of the tubes (4) flattened and extending from one of the open ends of said tubes (4). Manufacturing method according to any one of claims 6 and 7, characterized in that the shaping of the bottoms (2) of the packaging bags (1), from tubes (4) having two lateral tabs (3, 3 ' ) and two median tabs (6, 6 '), consists in making grooves (14) at an angle extending from the folding edges (15, 15') of the flattened tube at the ends of the rectilinear incisions (13), then discarding the bottom of the tube (4) and to fold the middle tabs (3, 3 ') towards each other, by deforming the tube (4) along the grooves (14) previously crushed, then assembling the free ends of the lateral tongues (3, 3 ') by thermal welding of their overlap zones (16), to be joined by thermal welding the longitudinal edges (5) of the lateral tongues (3, 3') folded with the internal face of the tube (4) at the bases (7) of the middle tabs (6, 6 '), to cut the middle tabs (6, 6') to given lengths s, depending on the dimensions of the bottom (2) desired, to coat said median tabs (6, 6 ') with an adhesive, and, finally, to successively fold the median tabs (6, 6') at their bases ( 7) along fold lines determined by the inner edges (10) of the assembly zones (11) of the longitudinal edges (5) of the lateral tabs (3, 3 ′), folding them over the latter with at least mutual overlap partial. Machine for shaping the bottom of a packaging bag according to any one of Claims 1 to 4, implementing the manufacturing method according to Claim 7, characterized in that it is mainly constituted by a series of stations shaping (17 to 21), namely, a device (17) for grooving by crushing, a device (18) for spacing the bottom of the tube (4), for folding the lateral tabs (3, 3 ') and d '' assembly of the latter by thermal welding, a device (19) for thermal welding of the longitudinal edges (5) of the lateral tabs (3, 3 '), a device (20) for cutting the middle tabs (6, 6') and a device (21) for gluing and folding the middle tabs (6, 6 ') the packaging bag (1) being formed being transported from one given shaping station (17, 18, 19, or 20) to the next (18, 19, 20 or 21) by means drive belts (22). Machine according to claim 8, characterized in that the device (18) is composed, on the one hand, of two plates (28) for gripping and spacing the middle tabs (6, 6 '), pivotally mounted on axes of rotation (29) and controlled by jacks (30), on the other hand, of two electrodes (31), which can be moved towards each other, from the folding edges (15, 15 ' ) of the tube (4) in position, for the folding of the lateral tabs (3, 3 ') along the grooves (14) and their assembly by thermal welding at the covering zones (16) of their free ends and, finally, a sheet (32) ensuring the folding of the welding strip obtained. Machine according to either of Claims 8 and 9, characterized in that the device (21) consists, on the one hand, of an adhesive application block (40) provided with several dispensing orifices (41) and, on the other hand, by folding guides (42, 42 '), the gluing and folding of the middle tabs (6, 6') being effected by the movement of movement of the packaging bag (1) driven by the drive belts (22).

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