EP0279762A1 - Device for producing a bag of flexible synthetic material, method for making the bag and the bag obtained - Google Patents

Abstract

A sleeve in a material which can be cold drawn (7) surrounds a cushion, by means of jaws around which it is formed. <IMAGE>

Description

The present invention relates to a device for producing a flexible plastic bag for packaging liquids, said bag being firstly in the form of a cushion already filled with liquid, device for reporting on said cushion means for gripping, stiffening and supporting information and to conform the sachet in its final form of marketing and use. The invention also relates to a method for producing such sachets as well as the sachets thus obtained.

A device of this type has already been proposed by the applicant, for example in the European patent issued 167469. In the device described therein, a cushion provided with a handle or stiffening element is brought into a compression means where its final conformation is ensured. Although it is entirely satisfactory, this device nevertheless has some drawbacks insofar as the handle is applied to the cushion before it is filled, which implies very rigorous control of the asepsis conditions.

Furthermore, difficulties are encountered in obtaining a precise and regular positioning of the stiffening element. A device for installing such a stiffening element has been proposed for example in the European patent issued 146482 in the name of the applicant.

It appeared that all these drawbacks were mainly linked to the fact that the stiffening element is attached by gluing or welding to the tubular sheath leading to the subsequent formation of the cushions, filled with liquid.

The object of the invention is therefore to propose a device making it possible to remedy these drawbacks of the prior art, that is to say allowing a stiffening element to be brought back without problem of asepsis, gripping and presenting information on a cushion already filled with liquid.

In accordance with the invention, this result is obtained with a device for producing a flexible plastic bag intended for the packaging of liquids, said bag being initially presented in the form of a cushion already filled with liquid, device for attaching to said cushion a means of gripping, stiffening and supporting information and to conform the sachet in its final form of marketing and use, characterized in that it comprises means for enclosing the cushion in a sleeve in in stretchable synthetic material cold formed around jaws movable in translation and in spacing relative to each other between which the cushion is disposed.

Advantageously, the cushion will be provided with an opening-closing plug attached thereto under aseptic conditions, said plug serving as a guide means for ensuring the precise positioning of the cushion in the device of the invention between said jaws.

According to a particular characteristic of implementation of the invention, the device will make it possible to apply two stiffening elements which will each be held on a lateral face of the cushion only by the sleeve when the jaws have been removed, the device further comprising means for conforming the bottom of the bag by gluing one on the other of the free ends of each of the stiffening elements.

As a variant, provision could be made for the device to apply a single stiffening element to the bottom of the cushion, the two wings then being folded down on the lateral faces of the cushion by vertical pistons before the installation of the stretchable sleeve.

According to another characteristic of the invention, a method is proposed for producing a flexible plastic bag provided with gripping, stiffening and information support means, characterized in that said means are attached to at least one lateral face of said sachet and held thereon only under the action of a sleeve of cold-stretchable synthetic material.

Finally, the invention also relates to sachets of the above type, that is to say in which a means of stiffening, gripping and information support is attached to at least one lateral face of said sachet and it is held there only under the action of a sleeve of cold-stretchable synthetic material.

• - la figure 1 est une vue schématique en perspective des principaux éléments constitutifs du dispositif de l'invention ;
• - la figure 2 est une élévation schématique du dispositif de l'invention ;
• - la figure 3 est une vue latérale schématique du dispositif de l'invention ;
  • - la figure 3A est une vue suivant A du poste de prise des renforts ;
  • - la figure 3B est une vue suivant B du poste de pressage et soudure de trois cornes du coussin, avant le début de l'opération et après achévement de celle-ci ;
  • - la figure 3C est une vue suivant C du poste d'encollage d'une aile d'un renfort ;
  • - la figure 3D est une vue suivant D du poste de collage des deux ailes l'une sur l'autre ;
• - la figure 4 est une vue en coupe de la mâchoire d'une pince ;
  • - la figure 4A est une vue suivant F de la mâchoire de la figure 4 ;
• - la figure 5 illustre plus en détails en perspective le poste de conformation du manchon étirable ;
• - la figure 6 est une vue en perspective du poste de prise des renforts par les mâchoires des pinces ;
• - la figure 7 est une vue d'un sachet conforme à l'invention.

The invention will be better understood with the aid of the description below of an embodiment, given by way of nonlimiting example, with reference to the appended drawings in which:

• - Figure 1 is a schematic perspective view of the main components of the device of the invention;
• - Figure 2 is a schematic elevation of the device of the invention;
• - Figure 3 is a schematic side view of the device of the invention;
  • - Figure 3A is a view along A of the position of reinforcements;
  • - Figure 3B is a view along B of the pressing and welding station of three horns of the cushion, before the start of the operation and after completion thereof;
  • - Figure 3C is a view along C of the gluing station of a wing of a reinforcement;
  • - Figure 3D is a view along D of the bonding station of the two wings on one another;
• - Figure 4 is a sectional view of the jaw of a clamp;
  • - Figure 4A is a view along F of the jaw of Figure 4;
• - Figure 5 illustrates in more detail in perspective the shaping station of the stretchable sleeve;
• - Figure 6 is a perspective view of the position of reinforcements taken by the jaws of the clamps;
• - Figure 7 is a view of a bag according to the invention.

We will first refer to Figure 1.

The main constituent elements of the device of the invention are shown there, generally referenced (1), namely:
- a reinforcement supply store (2) (3);
- a reel (4) of cold stretch film (5);
- a clamp of the cutting soldering station (6) of the film (5) to conform it into a sleeve (7);
- a chute (8) for supplying the cushions;
- a flat rail (9) on which the bottoms of the bags travel;
- a welding station (10) of the lower corners of the bag;
- a gluing station (11) of the wing of one of the reinforcements;
- A bonding station (12) of the reinforcement wings therebetween;
- A station (13) for evacuating the finished sachets evacuating them, for example, to a bagging (14) and a conveyor belt (15).

In Figure 1 are shown some peripheral elements to the device of the invention and which do not appear in other representations. They will be described below succinctly.

The device (1) is supplied by flexible bags already filled with liquid to be packaged and provided with a stopper-stopper seal as described for example in patent application in France 86.09615 in the name of the applicant. These are sort of "pillows" of liquid.

These are brought to the chute (8) and guided, therefore oriented, by their stopper which is subject to move in the guide lumen (16) thus bringing said cushions into a precise predetermined position. between the jaws of the device (1), which will be explained later.

When they fall on the rail (9), the cushions assume a shape shown schematically in Figure 3B. Thus, the two lower corners form horns projecting downward, as also illustrated in the European patent issued 142456 in the name of the applicant. We also see in Figure 3B the aforementioned plug (17). It will be understood that the two upper horns, including the one comprising the plug (17), protrude upwards and for this reason the chute comprises a guide (18) which follows the cushion until it is in position on the rail and then disappears upwards, as shown diagrammatically in FIG. 3, to allow its passage and its progression towards the other stations.

At the end of the journey on the rail (9), the latter stops (see FIG. 3) and releases the bottom of the bag at the station (13). The jaws of the clamps, which are fixed from the top, then let the sachet slide which falls towards the bagging (overpacking station) (14) from where it is then evacuated by a conveyor belt (15).

We will now endeavor to describe the path of the cushion and the various interventions on it between its exit from the chute (8) and its evacuation to the station (13).

Upon its arrival through the chute in the actual shaping device, the cushion is integrated into a process already initialized upstream, as will be described.

We will first refer to Figure 2.

The functional basis of the device according to the invention consists of a plurality of pairs of jaws (19,20) parallel to each other, parallel to the rail (9) and able to move jointly parallel to the latter.

These jaws, each pair of which forms a sort of "clamp", move in indexed fashion step by step, or possibly continuously. Each clamp follows a complete cycle of the device until the evacuation before returning to the end of the process.

At this level, the clamp is presented as shown diagrammatically in FIG. 2.

By advancing one step (for an indexed advancement device), the clamp is presented at the position (21) for taking up the reinforcements. This station comprises at least one, preferably two stores (2,22) containing the reinforcements (3).

The reinforcements (3) have several functions on the bag finally obtained, namely:
- vertical and bottom stiffening elements, as disclosed in European patent application 197875 in the name of the applicant;
- gripping elements (handle) as disclosed in European patent issued 146482 in the name of the applicant;
- information carrier, which can receive, for example, classic labeling, with legally compulsory elements, the brand of the product, etc.

At the station (21) for taking up the reinforcements, the device has a ramp (23) provided on its two faces and parallel to the axis of travel of the suction cup clamps (24), for example three in number as shown in the figure 6. If there are two magazines (2,22), there will of course be two opposite sets of suction cups. The ramp (23) supporting the suction cups forms with a base (25) shown in Figure 6 a unit (23) movable in translation transversely relative to the axis of movement of the clamps on a slide (26). Thus, at this position, the crew (or ramp) (23) can move alternately from one store to another to take reinforcement there each time through the suction cups, possibly with pneumatic suction and servo-control adequate.

The structure of the magazines (2,22) is illustrated in FIG. 6. They comprise a carcass (27) for restraining the reinforcements which are guided therein by an elastic guide (28) up to the magazine exit, so as to - even known. A spring, not shown, biases the reinforcements towards the front outlet of the magazine. At this level, the reinforcements are temporarily maintained, until they are taken up by the suction cups, by elastic latches (29) integral for example with the carcass (27).

As can be seen in FIG. 2, it will be seen that the jaws of the clamp which is at the position for taking up the reinforcements are arranged between the front ends of the magazines (2,22) and the suction cups (24). The reinforcements must therefore be taken through the jaws (19, 20) which are perforated, as shown in FIG. 4A, as many orifices (30) as there are suction cups at the level of the jaw.

Then the suction cups return to the rest position and the reinforcements are held on each respective jaw by means of small lugs behind which they snap into place. Then the clamp, each jaw of which now supports a reinforcement, moves one step towards the next station which is that of the formation of the sleeve.

This item, generally referenced (6) in Figures 2 and 5, will now be described in detail.

It comprises a film supply reel (4) (5) which passes between two advance roller systems (31, 32) in themselves conventional. The feed reel and the feed rollers (reel) are vertical. They prepare the desired length of film so that it can completely envelop the assembly formed by the clamp and the two reinforcements without the film being stretched.

In practice, the clamp coming from the station (21) encounters a film stretched between the rollers (32) and (31) on which the adequate quantity of film has already been unwound, which is held there by brake shoes (33, 34). At this moment, brakes (35, 36) are released which are arranged symmetrically with respect to the preceding ones, on the other side with respect to the rollers (31, 32).

Such reel systems, possibly more sophisticated, are in themselves known and will therefore not be described in more detail. The movement of the rollers (31, 32) is for example ensured by jacks (37) and return springs (38) as shown diagrammatically in FIG. 5.

At this station, the film is unwound with a predetermined length and envelops the assembly formed by the clamp and the reinforcements which it carries.

The film is then welded and cut to form a sleeve. This operation is carried out as follows.

When the clamp has carried with it the portion of the film enveloping it on three faces, as shown in FIG. 5, a welding clamp with two bars (39.40) closes to form the sleeve around the clamp.

The bars (39,40) of the welding tongs have an asymmetrical displacement. Indeed, it has been observed that during the subsequent stretching of the sleeve (see below), the stretching was weak at the level of the reinforcements and maximum in the zone of the bag not comprising said reinforcements, that is to say between the clamps. So to avoid having vertical weld lines on this free zone, which is detrimental from an aesthetic point of view because at the output of the device these zones correspond to the transparent faces of the bag, the weld is carried out on the edge d 'a reinforcement, preferably the front reinforcement, that is to say on the plug side.

To achieve this result, one of the bars will be almost fixed and the second, for example the bar (40) will carry with it a length of film; the welding-cutting will be carried out at the edge (41).

For the next bag, the movements of the rollers are determined so that the corresponding weld on the film (5) will then be on the other edge (42) of the bag and so on.

At the exit from this welding-cutting station, there is therefore an assembly consisting of two jaws, on the outer face of which a reinforcement is arranged, the assembly being wrapped in an unstretched sleeve. To prevent it from slipping, it can for example be held in position by belts running parallel to the rail.

Then between the station (6) and the station for receiving the cushions from the chute, the jaws of the clamp are spread in a direction perpendicular to the rail, the spacing between the two jaws being adjusted according to the value of desired and admissible stretching for the film without tearing it, without breaking at the weld lines and without residual elongation.

The operation of the cushion receiving station between the jaws has already been explained above via the chute (8).

The cushion affects at this stage the configuration of FIG. 3B, on the left in the figure, the two lower horns (43) affecting said configuration, that is to say projecting downward relative to the rail.

The liquid contained in the horns (43) is expelled therefrom by a pair of pressing and welding jaws (44,45), the structure of which is the subject of another patent application filed on the same day by the applicant. . Welding and pressing are carried out in any event through the fender flange (46) which also extends downwards, said filler being made of cardboard coated at this point with polyethylene on its internal face for welding.

On the right-hand side of FIG. 3B, the final position of the jaws (44, 45) is shown, the liquid being completely expelled from the horns and the latter being now welded.

At the same time, a clamp (47) of the same type as the previous ones expels the liquid contained in the upper horn (48) opposite the stopper. A weld is made at the same time, preferably without cutting.

Then one of the wings is glued (49) by a gluing nozzle (50) as illustrated in FIG. 3C. At the next post (12), the two wings are folded one against the other and therefore glued together by means of two pairs of pistons (51) arranged on each side of the rail and provided with teeth interlocking in others. This produces a pressing of the two wings and a bonding thereof between them.

At this same station, a corner (52) mechanically inserts the welded horn (48) between the body of the bag and the rear buttress.

Then at the next station, the rail stops and the bag falls towards the bagging and overwrapping stations as described above, after bringing the jaws together and retracting the sleeve.

The clamps then return to the starting point of the device and the process is resumed.

In this regard, reference is made to FIGS. 4 and 4A where a clamp jaw is shown.

The jaws are fixed from the top and are subject to movement by rollers (53) in slides (54) forming a cam path. Thus, by the sole configuration of said cam path, the spacing or approximation of the jaws of the clamps is determined.

FIG. 7 shows a sachet obtained in accordance with the invention.

It is in the form of a flexible and generally transparent body (55) enclosed by lateral reinforcements (56, 57) joined at the base to form a bottom (58). The assembly is held by a sleeve (59).

The sachet of the invention can be sold in unit form or in multiple packaging.

It is more particularly intended for the packaging of liquid food products such as mineral water, spring water, table water, fruit and fruit drinks, milk drinks, milk, etc.

Claims (21)

1. Device for producing a flexible plastic bag intended for the packaging of liquids, said bag being initially presented in the form of a cushion already filled with liquid, device making it possible to attach to said cushion a means of gripping, stiffening and supporting information and conforming the sachet in its final form of marketing and use, characterized in that it comprises means for enclosing the cushion in a sleeve (59) made of stretchable synthetic material formed cold around jaws (19,20) movable in translation and in spacing relative to each other between which the cushion is disposed. 2. Device according to claim 1, characterized in that the cushion is provided with an opening-closing plug (17) attached thereto under aseptic conditions, said plug serving as a guide means for ensuring precise positioning cushion in the device of the invention between said jaws, through a chute (8) having a guide lumen (16). 3. Device according to any one of claims 1 and 2, characterized in that it comprises means for applying two stiffening elements which will each be held on a lateral face of the cushion only by the sleeve when the jaws have been removed, the device further comprising means for shaping the bottom of the bag by gluing one on the other of the free ends of each of the stiffening elements. 4. Device according to any one of claims 1 and 2, characterized in that it comprises means for applying a single stiffening element to the bottom of the cushion, the two wings then being folded down on the lateral faces of the cushion by vertical pistons before installing the stretch sleeve. 5. Device according to any one of claims 1 and 3, characterized in that it comprises the following stations:
- a reinforcement supply store (2) (3);
- a reel (4) of cold stretch film (5);
- a station for cutting welding (6) of the film (5) to conform it into a sleeve (7);
- a chute (8) for supplying the cushions;
- a flat rail (9) on which the bottoms of the bags travel;
- a welding station (10) of the lower corners of the bag;
- a gluing station (11) of the wing of one of the reinforcements;
- A bonding station (12) of the reinforcement wings therebetween;
- A station (13) for evacuating the finished sachets evacuating them, for example, to a bagging (14) and a conveyor belt (15). 6. Device according to claim 5, characterized in that it comprises a plurality of pairs of jaws (19,20), mutually parallel, parallel to the rail (9) and able to move jointly parallel to the latter, said jaws moving indexed step by step or continuously along the entire path of the device (1) to the end of the rail (9) before returning to the end of the process. 7. Device according to claim 6, characterized in that the jaws are fixed from the top and are subject to move by rollers (53) in slides (54) forming a cam path, the only configuration of said cam path determining the spacing or approximation of the jaws relative to each other. 8. Device according to any one of claims 1 to 7, characterized in that the station (21) for taking reinforcements (3) by the jaws comprises at least one, preferably two magazines (2,22). 9. Device according to claim 1, characterized in that at the station (21) it comprises a ramp (23) provided on its two faces and parallel to the axis of travel of the jaws of suction cups (24), said ramp forming with a base (25) an assembly (23) movable in translation transversely with respect to the axis of movement of the jaws on a slide (26). 10. Device according to any one of claims 8 and 9, characterized in that the reinforcements (3) are temporarily maintained, until they are taken up by the suction cups, by elastic latches (29). 11. Device according to any one of claims 8 to 10, characterized in that the taking of the reinforcements takes place through the jaws (19,20) which are perforated with as many orifices (30) as there are has suction cups. 12. Device according to any one of claims 1 to 11, characterized in that the sleeve forming station comprises a film supply reel (4) (5) which passes between two advance roller systems (31 , 32) said reel and said rollers being with vertical axes, the film being caused to wrap the assembly formed by the two jaws and the two reinforcements which they support without stretching thereof. 13. Device according to claim 12, characterized in that it comprises a welding clamp with two bars (39.40) with symmetrical displacement so that the welding-cutting lines are located at the edge ( 41) of the reinforcement. 14. Device according to any one of claims 12 and 13, characterized in that at the station outlet (6) the unstretched sleeve is held in position by belts running parallel to the rail (9). 15. Device according to any one of claims 1 to 14, characterized in that between the station (6) and the station for receiving the cushions from the chute, the jaws are spaced apart from one another in direction perpendicular to the rail. 16. Device according to any one of claims 1 to 15, characterized in that the horns formed by the cushion in the device (1) are emptied and welded without cutting. 17. Device according to any one of claims 5 to 16, characterized in that one of the wings (49) is glued by a gluing nozzle (50), the two wings then being folded one against the other and glued to each other by means of two pairs of pistons (51) arranged on each side of the rail and provided with teeth interlocking with one another. 18. Device according to any one of claims 5 to 17, characterized in that a wedge (52) mechanically inserts the welded horn (48) between the body of the bag and the rear buttress. 19. Device according to any one of claims 5 to 18, characterized in that at the end of the course the rail (9) stops and releases the formed bag, the jaws, fixed from the top, allowing it to slide towards a strip conveyor (15). 20. Method for producing a flexible plastic bag provided with gripping, stiffening and information support means characterized in that said means are attached to at least one lateral face of said bag and held thereon only under the action of a sleeve of cold-stretchable synthetic material. 21. Bag in flexible synthetic material, characterized in that it comprises a flexible and generally transparent body (55) enclosed by lateral reinforcements (56, 57) joined at the base to form a bottom (58), the assembly being held by a sleeve (59) of cold stretch material.

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