EP0792802B1 - Automatic machine for forming, filling and closing of bags with transverse closure profiles - Google Patents

Abstract

The machine incorporates a straight guide (100) situated transversely above the film and designed to position at least one of the closure strips with precision, and a gripper (150) for the end of the closure strip which is designed to draw it along the guide. The machine has a neck (20) which shapes the plastic film (F) into a tube, a funnel (30) through which the packages are filled, and guides (200, 202, 204) to position and fix the closure strips across the film before it is shaped. It also has welding elements (40, 50) to form a continuous lengthwise weld which makes the plastic film strip into a tube, and transverse welds between packages.

Description

The present invention relates to the field of bags or sachets comprising complementary closure profiles suitable for allow successive openings and closings at will the user.

More specifically, the present invention relates to the field machines therefor, especially machines adapted for formation, filling and automatic closing of packaging based of film, in particular of thermoplastic material, comprising profiles additional fasteners, for example closing profiles male and female complementary.

Such machines are often called FFS, corresponding with the initials of the English expression "Form, Fill and Seal Machine".

Many machines of this type have already been proposed (see by example, documents EP-A-528721 and US-A-4894975).

Most of these machines include a forming collar which receives the film in the planar state from an unwinder and supplies the film shaped into a tube, a filling spout which opens into this forming neck and consequently into said tube, means for conveying and securing closure profiles on the film, longitudinal welding means for closing the tube longitudinally and means capable of sequentially generating a first transverse weld before a product is introduced into the tube through the filler neck, then a second weld transverse when the product has been introduced into the tube, to close a wrapping around the latter.

More precisely still, the majority of machines so far proposed are designed to receive the closing profiles in longitudinal direction, i.e. parallel to the direction of travel of the film. However, these machines with longitudinal profiles have the disadvantage of limiting the height of the bags obtained. This height is in effect equal to half the circumference of the forming neck. In addition, packaging obtained on these machines sometimes has defects sealing. This results in particular from the fact that the welding means transverse are disturbed in their operation by the extra thickness formed by the longitudinal profiles.

Many attempts have been made to try to improve this situation, by arranging the non-point closure profiles longitudinally, i.e. parallel to the direction of travel of the film, but transversely, i.e. perpendicular to the direction of film scrolling.

The first attempt on the subject, known to the inventors, is described in documents US-A-4617683 and US-A-4655862. These documents which date back ten years have proposed two solutions for route the transverse profiles on the film, in the planar state, before it does not reach the forming neck. The first solution is to laterally move sections of closure profiles using drive rollers placed laterally at the edge of the moving film, in combination with an aspirating displacement gripping head transverse. The second solution consists in depositing profiles of closure on the film using a rotary barrel provided with means of pneumatically operated temporary retainer.

The attempts thus proposed have shown promise in first time. However, these ultimately did not yield satisfaction and have been abandoned by specialists. In particular, it has found that the means described in the aforementioned documents do not not always allow the profiles to be deposited in the perfect state straight on the film. And therefore, it is often difficult to do cooperate with complementary profiles.

Other solutions were then proposed to try to compensate for the disadvantages resulting from the means of implementation described in the aforementioned documents.

We have proposed for example in document US-A-4666536 to roll up part of the film on a mandrel and route on this rolled-up part of the film, a section of closure profiles, oriented along the width of the film, using a heating tunnel ensuring the fixing profiles. The means described in this document have the advantage theoretical to authorize continuous scrolling training. However, they prove to be very complex and difficult to implement.

Document US-A-4701361 has proposed, to form a film provided sequentially of complementary closure profiles, to realize, by extrusion, a tubular film provided with helical closure profiles, extruded or added, then cut the tubular film in a helix to obtain a strip provided with equi-distributed transverse profiles.

Document US-A-4709398 describes a bag forming machine by horizontal movement and conformation of a film, which includes a means of grip designed to move closure profiles transversely on the movie.

Document US-A-4878987 proposed, to reduce the length profiles deposited on the film, and therefore improve the positioning of these, to supply the profiles not using of a lateral reserve, as described in documents US-A-4617683 and US-A-4655862, but using two reserves of profiles arranged respectively on each side of the film intended to form the bags. So, each of the two sections of sections displaced on the film, respectively from each lateral reserve, no longer covers the entire width of the film, but only half of it.

Document US-A-4844759 then proposed two other solutions. The first of these solutions is to train the profiles of closing, using an endless belt on a stirrup superimposed on the film and pivotable by 180 °, to turn the closure profiles over said film. Thus, the profiles are routed initially, relief directed towards the film, on the stirrup, then returned, relief directed away from the film, to be attached to it. The second solution is to route transversely the profiles on a shoe superimposed on the film and then lower it against the film to secure the profiles of closing.

The document US-A-4909017 describes a machine of the FFS type which comprises a straight guide superimposed on the film, transverse to it, to position a closure profile, transversely above the film.

After noting that none of the techniques described in the aforementioned documents are not satisfactory, it was proposed in the document US-A-5111643 a completely different approach, consisting not point to fix the closing profiles on the film, before routing this on the forming neck as described in the aforementioned documents, but first of all to conform the film in tube, on the forming tube, then forward the closure profiles on the tubular film. AT to this end, document US-A-5111643 proposes a complex installation comprising a chute which opens at the base of the forming neck for route the closure profiles carried by a support strip, and a discharge chute for the support strip.

The present invention now aims to improve training machines, film-based packaging with additional closing profiles.

This object is achieved, according to the present invention thanks to a machine according to claim 1, the preamble of which is based on document US-A-4,909,017.

The invention preferably applies to machines for automatic formation, filling and closing of packaging based on film, of the type known per se comprising a forming neck which receives in input the film in the planar state from an unwinder and provides exit the film shaped into a tube, a filling chute which opens in this forming neck and therefore in said tube, means for route closure profiles transversely on the front film that it does not reach the forming neck and to fix these on the film, longitudinal welding means for closing the tube longitudinally and means capable of sequentially generating a first transverse weld before a product is introduced into the tube through the filler neck, then a second weld transverse when the product has been introduced into the tube, to close a wrapping around the latter.

Thus, the present invention goes against the prejudice linked to means of implementation described in the first documents US-A-4617683 and US-A-4655862. Indeed, while many designers have considered that the means described in these documents could not give satisfaction, which led to the many subsequent proposals recalled above, the present inventors, after numerous experiments have found that a solution inspired by the means described in these documents US-A-4617683 and US-A-4655862, could give satisfaction, subject to improvement consisting in combining a straight guide and a gripping means operating by traction on closing profiles.

According to another advantageous characteristic of the invention, the means for conveying the closure profiles are suitable for fixing on the film one of two complementary profiles, in engagement, having each a length on the order of half the width of the film, and it's further provided means capable of fixing the second closure profile, on the inner wall of the film shaped into a sachet, after filling with this, when the sachet is finished.

To facilitate these operations of fixing the profiles of closing in two stages, preferably the two closing profiles are carried by different width support bands.

• la figure 1 représente une vue schématique en perspective d'une machine de formation remplissage et fermeture automatique de sacs conforme à la présente invention,
• les figures 2 et 3 illustrent schématiquement deux variantes de mise en oeuvre de l'invention,
• la figure 4 est une vue en coupe verticale de la machine selon la vue référencée II-II sur la figure 1,
• la figure 5 représente une vue latérale d'un sac conforme à la présente invention, et
• la figure 6 représente une vue en perspective d'un sac à soufflets conforme à la présente invention.

Other characteristics, aims and advantages of the present invention will appear on reading the detailed description which follows, and with reference to the appended drawings given by way of nonlimiting example and in which:

• FIG. 1 represents a schematic perspective view of a machine for filling and automatically closing bags according to the present invention,
• FIGS. 2 and 3 schematically illustrate two alternative embodiments of the invention,
• FIG. 4 is a view in vertical section of the machine according to the view referenced II-II in FIG. 1,
• FIG. 5 represents a side view of a bag according to the present invention, and
• Figure 6 shows a perspective view of a bellows bag according to the present invention.

• des moyens 10 d'acheminement du film F,
• un col de formage 20,
• une goulotte de remplissage 30,
• des moyens 40 de soudure longitudinale, et
• des moyens 50 de soudure transversale et de séparation des sacs.

The conventional general structure of a machine for forming, filling and automatically closing bags, with complementary closure profiles, comprising:

• means 10 for conveying the film F,
• a forming neck 20,
• a filling chute 30,
• means 40 for longitudinal welding, and
• means 50 for transverse welding and separation of the bags.

This general structure being known, it will not be described in more detail later.

• un guide rectiligne 100 superposé au film F, transversalement à la direction de déplacement de celui-ci, en amont du col de formage 20 ; ce guide 100 étant conçu pour positionner avec précision au moins un profilé de fermeture P, transversalement au-dessus du film F, et
• un moyen 150 de préhension de l'extrémité amont du profilé de fermeture P ; lequel moyen de préhension 150 est susceptible de déplacement transversal, le long du guide 100, pour acheminer le profilé de fermeture P dans ce dernier par traction sur l'extrémité amont du profilé de fermeture.

However, as indicated above, according to the invention, in order to correctly convey the closure sections P, transversely, on the film F, before the latter reaches the forming neck 20, provision is made:

• a straight guide 100 superimposed on the film F, transverse to the direction of movement of the latter, upstream from the forming neck 20; this guide 100 being designed to precisely position at least one closure profile P, transversely above the film F, and
• means 150 for gripping the upstream end of the closure profile P; which gripping means 150 is capable of transverse displacement, along the guide 100, to convey the closure profile P therein by traction on the upstream end of the closure profile.

The rectilinear guide 100 can be the subject of different modes of production.

The straight guide 100 is consisting of a channel formed by two pivoting jaws, receiving in position closing, the profile P conveyed by the means 150, but susceptible to facilitate the removal of the P profiles on the films underlying F.

The gripping means 150 can also be the subject of different embodiments.

As shown schematically in Figure 1 attached, of preferably, these gripping means are formed by a clamp system commanded to close to grip the upstream end of a profile P, in order to route it through the straight guide 100, then open to release the P profile before resuming the initial position of gripping shown schematically in Figure 1.

According to an alternative embodiment, the gripping means 150 can be formed by a suction head.

Of course preferably, means are provided for transverse movement of the gripping means 150, synchronized with the displacement of film F.

Auxiliary means are preferably provided for the routing of profiles P: drive rollers 200, 202, a guide 204 of the profiles upstream of the film F, means 206 of sectioning of the P profiles, by section (the P profiles being preferably routed from a reel supply 208) and a position sensor 210.

The closing profiles P are fixed to the film F by any suitable means, advantageously using welding jaws, associated with the rectilinear guide 100, as shown diagrammatically under the reference 120 in figure 1.

Various methods of implementation can be provided for the deposition of the P profiles on the film F.

According to a first variant, the system is adapted to deposit closure profiles P covering the entire width of the film F, these profiles P being fixed on the film F over their entire length, as shown schematically on the Figure 3 and engaging only after folding and crushing of the film tubular after filling the bag, when finishing it.

However, according to another variant, as shown schematically on the Figure 2, the system can be adapted to deposit directly on the film F a pair of P-profiles in engagement, covering only half of the width of the film F, one P1 of the two profiles, adjacent to the film, being fixed on it at the depot, thanks to the welding jaws 120, while the second superimposed profile P2 is fixed on the internal wall of the sachet, when it is finished, after filling. In this case, the second profile P2 can be welded to the film F thanks to the jaws of solder 50, or again thanks to transverse solder jaws additional 52, as shown diagrammatically in FIG. 4.

In the context of this second solution, preferably, as illustrated in FIG. 4, the support strip 54 of the second profile P2 is more wider than the support strip 56 of the first profile P1, to facilitate the second weld.

The profile P being arranged transversely on the film F before that this does not reach the forming neck 20, provision is preferably made for means facilitating the passage of this forming neck 20.

To this end, provision can be made either to offset the forming neck 20 relative to the vertical axis of the machine, to allow the passage of transverse closing profiles P, i.e. to provide adequate clearance for forming neck level 20.

• comme schématisé sur la figure 5, la possibilité de réaliser des lignes de prédécoupe 80 entre les profilés de fermeture P et la seconde soudure transversale 82 (une telle ligne de prédécoupe peut être réalisée, de façon classique en soi grâce à des couteaux à dents associés aux mâchoires de soudure transversale 50),
• la possibilité de réaliser des soudures longitudinales incurvées dites type "porte manteau" comme illustré en 84 sur la figure 5, notamment pour des applications à contenu liquide. De telles soudures 84 ont une forme globalement arrondie, convexe vers l'intérieur du sachet, et convergent vers le sommet de celui-ci qui coïncide avec la seconde soudure transversale 82. Sur la figure 5, on a illustré en 86 la première soudure transversale et en 88 la soudure longitudinale réalisée à l'aide des mâchoires 40 pour relier entre eux les bords longitudinaux du film F. De préférence, les soudures longitudinales 84 en "porte manteau" sont symétriques par rapport à un plan médian du sachet transversal aux soudures 82, 86 et réalisées à l'aide de mâchoires de soudure de formes complémentaires,
• la possibilité de réaliser des sachets à soufflets latéraux 90, 92, comme schématisé sur la figure 6, grâce à la réalisation de plis longitudinaux sur le film F avant l'entrée sur le col de formage 20.

In addition, the sachets obtained themselves can be the subject of numerous variants, among which there may be mentioned:

• as shown diagrammatically in FIG. 5, the possibility of producing pre-cut lines 80 between the closure profiles P and the second transverse weld 82 (such a pre-cut line can be produced, in a conventional manner in itself thanks to knives with associated teeth to the transverse welding jaws 50),
• the possibility of making curved longitudinal welds known as the “coat rack” type as illustrated at 84 in FIG. 5, in particular for applications with liquid content. Such seals 84 have a generally rounded shape, convex towards the inside of the bag, and converge towards the top of the latter which coincides with the second transverse seal 82. In FIG. 5, the first transverse seal is illustrated at 86 and at 88 the longitudinal weld produced using the jaws 40 to connect the longitudinal edges of the film F to one another. Preferably, the longitudinal welds 84 in "coat hanger" are symmetrical with respect to a median plane of the bag transverse to the welds 82, 86 and produced using welding jaws of complementary shapes,
• the possibility of making bags with lateral bellows 90, 92, as shown diagrammatically in FIG. 6, by virtue of the production of longitudinal folds on the film F before entering the forming neck 20.

In FIG. 4, there is shown diagrammatically at 51 an associated cutting tool to the transverse welding jaws 50 to separate the bags one once completed, and we have diagrammed at 53 a cutting tool capable of being used to make the pre-cut line 80.

The closing profiles P themselves can be many variations.

As shown schematically in Figure 2, it can be additional asymmetrical male / female profiles P1 and P2.

It can also be as shown diagrammatically in FIG. 3 of P profiles of constant section able to engage after folding on themselves.

Preferably, means are provided, for example in the form of bi-material P profiles or equivalent means, used to define a melting temperature on the outer surface of the support strips 54, 56 below the melting temperature on their internal surfaces.

The film F used can also be the subject of numerous variants. It can be a flexible film made of monolayer plastic or multilayer, if necessary coated, for example metallized.

• le dépôt des profilés de fermeture P par traction, et sur un guide 100 permet un positionnement très précis sur la largeur du film F et à l'état rectiligne,
• une grande facilité de mise en oeuvre, et
• une bonne étanchéité (des profilés de fermeture s'étendent parallèlement aux moyens de soudure transversale 50 et ne perturbent pas le fonctionnement de ceux-ci).

The present invention offers numerous advantages over systems which previously existed and which include the following:

• depositing the closing profiles P by traction, and on a guide 100 allows very precise positioning over the width of the film F and in the rectilinear state,
• great ease of implementation, and
• good sealing (closure profiles extend parallel to the transverse welding means 50 and do not disturb the operation thereof).

Of course, the present invention is not limited to the modes of specific embodiments which have just been described, but extends to any variant according to his spirit.

Thus, the application of the invention to the above has been described previously. automatic forming, filling and closing machines film-based packaging.

However, the invention can also be applied to machines preparation of films equipped with profiles, which films equipped with profiles are then routed to supply machines for automatic formation, filling and closing of conventional packaging in themselves.

We have previously described gripping means formed either a clamp system, or a suction head. According to another variant, the gripping means can be formed by a needle carried by suitable training means for, on the one hand moving alternately the needle, by translation or pivoting, in approximation and distancing of the guide 100, to stitch the profile P in the close position of the guide and on the other hand move alternately the needle goes back and forth along the guide 100. More specifically, these training means are suitable for 1) bring the needle of the upstream end of the guide 100 to prick the free end from profile P coming from reserve 208, 2) move the needle along the guide 100 while keeping the needle in the close position engaged with the section for conveying it by traction on its upstream end, 3) move the needle away from the guide 100 to release the profile P at the end of the routing stroke, and 4) move the needle back the along the guide 100 towards the upstream end thereof while maintaining the needle in the free distant position relative to the profile, before repeat a training cycle from step 1) for the section following profile P.

Claims (19)

1. A machine for making packaging on the basis of film (F) that is provided with complementary closure ribs (P), the machine including means for conveying closure ribs transversely relative to the film (F) and comprising a rectilinear guide (100) superposed relative to the film (F) and extending transversely relative thereto, the guide being designed to position accurately at least one closure rib (P) transversely over the film (F); and the machine being characterized by the fact that the conveying means further include means (150) for grasping the leading end of the closure rib and capable of moving transversely along the guide (100) to convey the closure rib (P) therealong by pulling on the leading end of the closure rib, and by the fact that the rectilinear guide (100) is constituted by a channel formed by pivoting jaws suitable for opening so as to facilitate releasing the ribs.
2. A machine according to claim 1, characterized by the fact that the machine comprises a machine for automatically forming, filling, and closing packaging, said machine comprising: a former (20) that is fed with the film in the plane state coming from pay-out means and that delivers the film (F) shaped into a tube; a filler chute (30) that opens out into the former (20) and consequently into said tube; means (200, 202, 204) for conveying closure ribs (P) transversely relative to the film (F) before the film reaches the former (20) and for fixing the ribs to the film (F); longitudinal heat-sealing means (40) for closing the tube longitudinally; and means (50) suitable for sequentially generating a first transverse line of sealing before a product is put into the tube via the filler chute (30), and then a second transverse line of sealing when the product has been put into the tube, so as to close packaging around the product.
3. A machine according to claim 1, characterized by the fact that the machine constitutes a machine for preparing film fitted with closure ribs, which film fitted with closure ribs is subsequently fed to a machine for automatically forming, filling, and closing packaging.
4. A machine according to any one of claims 1 to 3, characterized by the fact that the means for conveying the closure ribs (P) are adapted to fix to the film (F) one of two mutually engaged complementary ribs (P1) each of length that is approximately equal to half the width of the film (F), and means (52) are also provided suitable for fixing the second closure rib (P2) to the inside wall of the film once shaped into a bag, after the bag has been filled, and while the bag is being finished.
5. A machine according to any one of claims 1 to 4, characterized by the fact that the two closure ribs (P1, P2) are carried by support strips (54, 56) of different widths.
6. A machine according to claim 5, characterized by the fact that the support strip (54) for the second-fixed closure rib (P2) is wider than the support strip (56) for the closure rib (P1) that is fixed in the positioning station.
7. A machine according to any one of claims 1 to 3, characterized by the fact that the means for conveying closure ribs (P) are adapted to fix on the film (F) a set of closure ribs (P) covering the entire width of the film (F), which closure set comes into engagement only after the tubular film (F) has been folded over and pressed shut, after the bag has been filled, while the bag is being finished.
8. A machine according to any one of claims 1 to 7, characterized by the fact that the grasping means (150) are constituted by a clamp system controlled to open and close.
9. A machine according to any one of claims 1 to 7, characterized by the fact that the grasping means (150) comprise a suction head.
10. A machine according to any one of claims 1 to 7, characterized by the fact that the grasping means (150) comprise a needle associated with means adapted to displace said needle back and forth towards and away from the rectilinear guide (100) to engage the rib (P) when close thereto and to move the needle back and forth along the guide to bring the closure rib into position by pulling on its leading end.
11. A machine according to any one of claims 1 to 10, characterized by the fact that means are provided for transversely displacing the grasping means (150) synchronously with displacement of the film (F).
12. A machine according to any one of claims 1 to 11, characterized by the fact that means (206) are provided for cutting the ribs (P) into lengths.
13. A machine according to any one of claims 1 to 12, characterized by the fact that the means (120) for fixing the closure ribs (P) on the film (F) are formed by heat-sealing jaws.
14. A machine according to any one of claims 1 to 13, characterized by the fact that it includes means (53) suitable for forming at least one precut line (80) between the closure ribs (P) and the second transverse line of sealing (82).
15. A machine according to any one of claims 1 to 14, characterized by the fact that it includes means (40) suitable for performing curved "coat-hanger" type longitudinal heat-sealing, in particular for applications in which the packaging contains a liquid.
16. A machine according to any one of claims 1 to 15, characterized by the fact that it includes means suitable for forming longitudinal folds in association with the film (F) prior to entering the former (20), so as to form bags having lateral gussets (90, 92).
17. A machine according to any one of claims 1 to 16, characterized by the fact that it includes means suitable for feeding asymmetrical and complementary male/female closure ribs (P).
18. A machine according to any one of claims 1 to 16, characterized by the fact that it includes means (208) suitable for feeding a rib (P) of constant section suitable for engaging with itself after being folded over.
19. A machine according to any one of claims 1 to 18, characterized by the fact that the ribs (P) are adapted to define a melting temperature on the outer surfaces of their support strips (54, 56) that is lower than the melting temperature on the inner surfaces thereof.

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