EP2006081B1 - Profile band positioning device - Google Patents

Description

The invention relates to a device for positioning strips of closure profiles pre-fitted with sliders relative to the longitudinal edges of a thermoplastic film and intended in particular for closing a bag, in a forming machine, welding and optionally filling bags. in automatic.

The relative positioning of the closure profile strips pre-fitted with sliders with respect to the edges of the film is a major difficulty posed by the production of bags on such automatic forming and welding machines, insofar as the strips of profiles and film slide on a forming neck.

However, the welding step is fundamental if it is desired that a bag is provided with a closure that is able to enclose the contents hermetically. But if the strips are too close radially to the forming neck (that is, if they overlap the edges of the film too much), the jaws of the welding device may close on the sliders, or the film disrupts their displacement. And conversely, if the strips are too far radially from the forming neck, the welding device can weld the edges of the film together, and not on the strips of closure profiles. Finally, if they are not brought parallel to the direction of travel of the thermoplastic film, the longitudinal edges of the film are partially welded together.

It is therefore necessary to find a means for satisfactorily balancing and positioning strips of closure profiles pre-fitted with sliders relative to the forming neck and the longitudinal edges of the thermoplastic film.

Various solutions have already been proposed.

One of them, described in the document WO 02/092434 , uses complementary closure profiles, pre-fitted with sliders and comprising separate support side sails which extend beyond closure profiles. A loop is made in a film intended to form the wall of the bag, and the assembly formed by the profiles and the webs is fixed in a concave part of the loop, on the surface of the film which corresponds to the outer surface of the bag.

This method makes it possible to ensure a correct welding of the strips of closure profiles on the longitudinal edges of the film.

Another device is known from US 6,047,521 A . However, it is not suitable for positioning profile strips provided with sliders.

An objective of the device of the invention is to provide another solution, less complex to implement, in order to properly position the closure strips and the sliders relative to the edges of the film.

This object is achieved within the scope of the present invention by means of a device according to claim 1.

• la figure 1 représente une vue schématique en perspective d'une machine de fabrication de sachets susceptible d'utiliser le dispositif de positionnement conforme à la présente invention,
• les figure 2 à 4 sont une représentation en coupe de trois variantes d'un premier mode de réalisation possible d'un dispositif selon l'invention,
• les figures 5 et 6 sont une représentation en coupe de deux variantes d'un deuxième mode de réalisation possible d'un dispositif selon l'invention.

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows, and with reference to the appended drawings in which:

• the figure 1 represents a schematic perspective view of a bag-making machine capable of using the positioning device according to the present invention,
• the figure 2 to 4 are a sectional representation of three variants of a first possible embodiment of a device according to the invention,
• the Figures 5 and 6 are a sectional representation of two variants of a second possible embodiment of a device according to the invention.

Identical references in these figures designate identical elements.

• des moyens d'approvisionnement d'une bande de profilés de fermeture 21,
• des moyens 22 d'approvisionnement de chaînes de curseurs,
• un poste 20 destiné à opérer séquentiellement la pose individuelle de chaque curseur sur ladite bande,
• un poste 30 destiné à assurer la « fermeture des bandes », c'est-à-dire l'engagement des deux profilés de la bande de fermeture, après pose des curseurs,
• des moyens d'approvisionnement 24 d'un film thermoplastique 11,
• un col de formage 3, associé à une goulotte de remplissage 40, qui conforme le film à partir d'un état initial plan, en un tube,
• un dispositif de positionnement 70 de la bande de fermeture 10 par rapport aux bords longitudinaux adjacents du film 11, associé à des mâchoires de soudure longitudinale 5, et
• des mâchoires de soudure transversale associées à des moyens de coupe 60.

The invention applies to the manufacture of sachets 80 for example on an automatic machine for manufacturing, preferably filling and closing sachets of the type illustrated schematically on the figure 1 . Such a machine comprises:

• means for supplying a strip of closure profiles 21,
• means 22 for supplying cursor chains,
• a station 20 for sequentially operating the individual installation of each cursor on said strip,
• a station 30 intended to ensure the "closing of the bands", that is to say the engagement of the two sections of the closure band, after setting the sliders,
• supply means 24 for a thermoplastic film 11,
• a forming neck 3, associated with a filler neck 40, which conforms the film from a flat initial state to a tube,
• a device 70 for positioning the closure strip 10 with respect to the adjacent longitudinal edges of the film 11, associated with longitudinal welding jaws 5, and
• transverse welding jaws associated with cutting means 60.

The invention applies to all types of closure strips 10 (in particular closure strips comprising two complementary male and female sections, hook profiles, etc.).

Each closure band 10 is fixed on a lateral support web which is integral therewith. Where appropriate, the support web is common and serves as an anti-burglary wall 13.

Similarly, the sliders 12 may be subject to numerous variants. Preferably, each slider is composed of a sole which carries, on one side, two lateral wings and a central separation rib, which define two convergent / divergent corridors according to the direction considered, each lane being intended to receive one of the strips of closure profiles 10.

The pitch of the sliders 12 on the closure profile strips 10 preferably corresponds to the size of the bags 80 to be formed.

The invention also applies to the manufacture of empty bags 80 for subsequent filling.

Different embodiments can be envisaged.

First embodiment

• ■ un guide 1 en U, s'étendant longitudinalement par rapport au col de formage 3, comprenant une paroi supérieure et deux ailes latérales. Les ailes latérales sont agencées de sorte à former un U avec la paroi supérieure et à définir ainsi un couloir.
• ■ deux plaques latérales de guidage 4, en matière plastique ou métallique, de préférence fixées sur le guide 1, parallèlement à ses ailes, et
• ■ un insert 2 rectangulaire, qui s'étend radialement depuis le col de formage 3 et parallèlement aux plaques latérales de guidage 4, en métal.

The positioning device 70 is preferably placed on the forming neck 3 of the bag 80. It comprises:

• A guide 1 in U, extending longitudinally with respect to the forming neck 3, comprising an upper wall and two lateral wings. The lateral wings are arranged so as to form a U with the upper wall and thus define a corridor.
• ■ two lateral guiding plates 4, made of plastic or metal, preferably fixed on the guide 1, parallel to its wings, and
• ■ a rectangular insert 2, which extends radially from the forming neck 3 and parallel to the lateral guide plates 4, metal.

The insert 2 is positioned between the lateral guide plates 4, under the corridor of the guide 1 and at a distance from its upper wall, so that there remains a space between each lateral face of the insert 2 and each plate 4. on the one hand, and between the insert 2 and the guide 1 on the other hand.

In order to achieve the objective of the invention, the film 11 is made to scroll and conform around the forming neck 3, so that the free longitudinal ends of the film 11 are applied against the rectangular insert 2 by the plates. lateral guiding 4 (these free longitudinal ends of the film 11 being inserted between the lateral guide plates 4 and the insert 2).

Plating the longitudinal edges of the film 11 against the insert by the two guide plates 4 ensures a good positioning of the film 11 and its holding in position at the time of welding.

Simultaneously, strips of profiles 10 pre-fitted with sliders 12 (for example by means of a slider installation device located upstream on the machine), preferably closed, are brought and placed on the film, between the insert 2 and the corridor formed by the U-shaped guide 1, with overlapping of the lateral support ribs of the profile strips 10 on the longitudinal edges of the film 11, as illustrated in FIG. figure 2 . The strips of closure profiles 10 are then oriented so that the sliders 12 are positioned between the insert 2 and the U-shaped guide 1, and that the webs are directed towards the forming neck 3.

The pre-fitted profiled strips 10 are then precisely maintained in radial position relative to the forming neck 3 and to the longitudinal edges of the film 11, on the one hand by the U-shaped guide 1 which serves as an external radial abutment, and on the other hand. secondly by the insert 2 which serves as internal radial abutment.

And the insert 2, by its positioning between the two longitudinal edges of the film 11 during welding, prevents their mutual welding.

Furthermore, the length of the guide 1 U is preferably at least equal to the distance between two sliders 12. The sliders thus constitute two supports, and ensure the stability and balance of the closure strips 10 during welding.

Preferably the guide plates 4 are fixed to the U-shaped guide 1 only at their longitudinal ends, so as not to hinder the passage of the longitudinal welding jaws 5.

In a variant, the U-shaped guide 1 furthermore comprises two longitudinal protrusions 1a and 1b, extending from the free end of the flanges towards the interior of the passage, parallel to the upper wall, so as to support the sliders 12 during the band welding (see for example Figures 5 and 6 ). This can further ensure maintaining the radial position of the profile strips.

In another variant, it is expected that the projections 1a and 1b extend longitudinally from the inner surface of the wings, or non-parallel to the upper wall.

When the strips of closure profiles 10 are carried by a common lateral support veil 13, which serves as an opening control and burglar-proof wall, the upper surface of the insert 2 matches the shape of the veil 13. For example , the surface is concave, or V-shaped, as shown in the Figures 3 and 4 .

Second embodiment

• ■ un guide 1 en U, s'étendant longitudinalement par rapport au col de formage. Le guide 1 comprend une paroi supérieure, deux parois latérales, et le cas échéant deux saillies 1a et 1b.
  Les ailes sont agencées de sorte à former un U avec la paroi supérieure et à définir ainsi un couloir, et les saillies 1a et 1b s'étendent de l'extrémité libre des ailes vers l'intérieur du couloir, parallèlement à la paroi supérieure, comme illustré sur la figure 5.
• ■ deux plaques latérales de guidage 4, en matière plastique ou métallique, fixées le long du guide 1 en U, et
• ■ deux doigts de guidage 6 en métal, parallèles entre eux, et s'étendant radialement depuis le col de formage 3.
  Chaque doigt comprend au moins une gorge de guidage 7, formée longitudinalement dans sa face intérieure (à savoir la face orientée vers l'autre doigt).

In this embodiment, the positioning device 70 is again placed preferably on the forming neck 3 of the bag. He understands :

• A guide 1 in U, extending longitudinally with respect to the forming neck. The guide 1 comprises an upper wall, two side walls, and optionally two projections 1a and 1b.
  The wings are arranged so as to form a U with the upper wall and thus define a corridor, and the projections 1a and 1b extend from the free end of the wings towards the interior of the corridor, parallel to the upper wall, as illustrated on the figure 5 .
• ■ two lateral guiding plates 4, made of plastic or metal, fixed along the U-shaped guide 1, and
• ■ two metal guide pins 6, mutually parallel, and extending radially from the forming neck 3.
  Each finger comprises at least one guide groove 7, formed longitudinally in its inner face (namely the face facing the other finger).

The guide fingers 6 are positioned between the lateral guide plates 4, under the guide 1 and at a distance from its upper wall, so that there remains a space between each finger 6 and a guide plate 4 of a part, and the fingers 6 and the guide 1 on the other hand.

Preferably the guide plates 4 are fixed to the U-shaped guide 1 only at their longitudinal ends, so as not to hinder the passage of the longitudinal welding jaws 5.

Alternatively, it is expected that the projections 1a and 1b extend from the inner surface of the wings (as shown in FIG. figure 6 ), or non-parallel to the upper wall of the guide 1.

As illustrated on the figure 5 , extra thicknesses or ribs 14 are formed longitudinally on the outer face of the support webs of the profile strips 10. Their shape and dimensions are complementary to those of the grooves 7 for guiding the fingers 6, so that said extra thicknesses or ribs 14 are suitable for be introduced and maintained radially in the grooves 7, while being able to move in the direction of travel.

In order to achieve the objective of the invention, the film 11 is made to scroll and conform around the forming neck 3, and each longitudinal edge of the thermoplastic film 11 is placed between the outer wall of one of the guide fingers. 6 and the corresponding lateral guide plate 4. The two guide plates 4 then hold the edges of the film 11 pressed against the guide fingers 6.

At the same time, the extra thicknesses or ribs 14 are engaged in the guide grooves 7 of the lateral guide plates 6. The closure strips 10 are also positioned in such a way that the sliders 12 are guided in the corridor formed by the U-shaped guide 1. and rest on the projections 1a and 1b, so that they are maintained at a predetermined fixed distance from the forming neck 3. This ensures the radial positioning of the strips of profiles 10 on which the sliders are mounted relative to the longitudinal edges of the film 11.

The longitudinal welding jaws 5 then weld the longitudinal edges of the thermoplastic film 11 on the side webs of the profile strips 10 by closing over the guide fingers 6.

Preferably, the length of the guide 1 in U is at least equal to the distance between two sliders 12. These sliders then form two supports, and ensure the stability and balance of the closure strips 10 during welding.

As a variant, it is possible to form the extra thicknesses or ribs on the free ends of the film, and the complementary guide grooves on the outer surface of each finger 6, or that the guide fingers 6 comprise, on their inner surface, longitudinal ribs 8 penetrating into complementary grooves 15 formed on the strips of closure profiles 10, as illustrated in FIG. figure 6 .

Where appropriate, it is intended to associate the positioning device 70 with a cutting system designed to cut longitudinal edges of the film 11, in order to guarantee perfect positioning coincidence of the two longitudinal edges of the film 11 and to avoid any disturbance of the displacement. slider 12.

It can further be provided that one of the longitudinal edges of the film 11 protrudes beyond the closure band 10 and associated sliders 12, to form for example a handle.

Naturally, the present invention is not limited to the particular embodiments which have just been described but extends to any variant within the scope of the claims.

Claims (20)

1. Device (70) for positioning closing profile strips (10) provided with a plurality of sliders with respect to the longitudinal edges of a tubular thermoplastic film (11), comprising at least one external radial stop (1) constituting a guide that extends longitudinally with respect to a forming neck (3),
   characterised in that the length of said external radial stop (1) is at least equal to the distance separating two successive sliders (12) on the profile bands (10) such that it is adapted to guide the sliders along the forming neck (3), and in that the device further comprises lateral guiding plates (4) extending longitudinally with respect to the forming neck (3) and also on each side of the external radial stop (2) in order to position the thermoplastic film (11) on the forming neck (3) and an internal radial stop (2, 6), extending radially from the forming neck (3) between the lateral guiding plates (4) adapted to place in position the closing profile strips with respect to the longitudinal edges of the thermoplastic film (11).
2. Device (70) according to the preceding claim, characterised in that the guide (1) comprises an upper wall and two lateral walls arranged so as to form a U-shape with the upper wall and thereby defining a passage.
3. Device (70) according to the preceding claim, characterised in that the lateral guiding plates extend along the external radial stop (1).
4. Device (70) according to claim 3, characterised in that the lateral guiding plates (4) are made of plastics or metal.
5. Device (70) according to one of the preceding claims, characterised in that the closing profile strips (10) comprise a common support lateral web (13).
6. Device (70) according to the preceding claim, characterised in that the common support lateral web (13) is an evidence of opening.
7. Device (70) according to the preceding claim, characterised in that the internal radial stop (2) is an insert that extends radially from the forming neck (3).
8. Device (70) according to the preceding claim, characterised in that the insert (2) has a rectangular shape.
9. Device (70) according to one of claims 7 or 8, characterised in that the upper surface of the insert (2) is concave or V-shaped.
10. Device (70) according to claim 1, characterised in that the internal radial stop (2) comprises two guiding fingers (6) parallel to each other, and extending radially from the forming neck (3).
11. Device (70) according to the preceding claim, characterised in that the guiding fingers (6) comprise at least one longitudinal guiding throat (7) complementary to an extra thickness (14) formed longitudinally on a support web of the closing profile strips (10).
12. Device (70) according to claim 10, characterised in that the guiding fingers (6) comprise at least one longitudinal rib (8) complementary to a throat (15) formed longitudinally on a support web of the closing profile strips (10).
13. Device (70) according to one of claims 10 to 12, characterised in that the internal radial stop (2, 6) is made of metal.
14. Device (70) according to any of claims 1 to 13, characterised in that the external radial stop (1) is a guide that extends longitudinally with respect to a forming neck (3) and that the guide (1) further comprises two longitudinal projections (la, 1b), which extend from the inner surface of the lateral wings of the guide (1).
15. Device (70) according to the preceding claim, characterised in that the sliders (12), which are positioned on the profile bands (10), rest on the projections (1b) of the guide (1).
16. Device (70) according to any of the preceding claims, characterised in that the external radial stop (1) is made of plastics or metal.
17. Device (70) according to any of the preceding claims, characterised in that it is associated with longitudinal welding jaws (5).
18. Device (70) according to any of the preceding claims, characterised in that it is associated with traversal welding jaws (60).
19. Device (70) according to any of the preceding claims, characterised in that it is associated with longitudinal cutting means.
20. Machine for manufacturing a bag (80) equipped with a sealing profile band (10) provided with sliders (12), characterised in that it comprises a device (70) according to one of claims 1 to 19.

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