Method and machine for the automatic manufacture of bags, as well as the bags thus obtained

The present invention relates to the field of manufacturing automatic bags or pouches comprising closure strips further adapted to allow opening and closing successive, at will of the user.

Many means have already been proposed for this purpose, both at level profiles, as machines and methods for making such bags or pouches.

Examples of such means may be found in US-A-5242516, US-A-5216787, FR-A-2613326, US-A-4909 017, US-A-4,617,683, US-A-4709533, EP-A-0398732, EP-A-0635433, US-A-4,817,188 and US-A-5,412,924.

The present invention now aims to propose new ways of achieving such pouches or bags comprising complementary closure profiles.

This object is achieved in the context of the present invention by a forming process and sealing bags, comprising the steps of:<ul><li>provide a closure means comprising at least two sections Further arranged on two respective support webs,</li><li>providing a support film for composing the walls of the bag,</li><li>weld a web of the closure means on the film at one of the least one of the longitudinal edges of said web, the closure means being oriented transversely to the longitudinal direction of the film,</li><li>conform the film thus provided with the closure means in the form of a tube, then</li><li>welding the second web of the closing means on an opposite face of film at only one edge of said second web.</li></ul>

The present invention also relates to a machine for the implementation of this method, as well as sachets and products intermediates obtained by this process.

Other features, objects and advantages of the present invention appear on reading the detailed description that follows, reference to the appended drawings, given by way of nonlimiting examples and on which ones :<ul><li>1 shows a schematic perspective view of a machine forming, filling and automatic closing of bags, according to invention</li><li>Figures 2 to 4 show side views of the film equipped with the means closing, upstream of a forming neck, according to three variants of embodiments according to the present invention,</li><li>5 shows a cross-sectional view of the top of a bag obtained using such a machine, and</li><li>6 shows an embodiment of a closure means variant can be implemented in the context of the present invention.</li></ul>

We can see in Figure 1 attached a forming machine, automatic filling and closing bags comprising profiles of Additional closing 100, which machine includes:<ul><li>means 10 for feeding a film F in a direction The longitudinal</li><li>a forming collar 20,</li><li>a filling chute 30,</li><li>means 40 for longitudinal welding and</li><li>means 50 for transverse welding and separating bags.</li></ul>

The forming throat 20 receives as input the film F in the plane state (and provided the closure means 100 as will be specified later). He gives outputting the film F formed into the tube. In the context of the present invention the term "tube" or "tubular" should not be regarded as limited to a tubular section of revolution. It also includes including any polygonal tubular section.

The filler pipe 30 opens out into the forming neck 20 and in the tube formed by the film F at the outlet of the forming throat 20.

The means 40 for longitudinal seal adapted to close the tube thus formed by joining the two longitudinal edges of the film F

The means 50 are preferably transverse weld suitable for sequentially generating a first transverse weld 52 before a product is introduced into the tube via the chute filling 30, and then a second transverse weld when the product 54 was introduced into the tube, to close a bag around the latter. In practice, as one suspects the examination of Figure 1, these two welds transverse 52 and 54 can be generated simultaneously on both side of cutting means 56 ensuring the separation of the bags, with sealing jaws 50 doubles.

The welding means 40 and 50 are preferably formed of animated heated jaws of a cyclic displacement towards and away from the film in a direction orthogonal to the axis of movement thereof.

This general machine structure is known, it will not be described in more detail below.

In the context of the present invention, the machine comprises outraged<ul><li>means 60 adapted to provide T sections a means of closure 100 comprising two elements 110, 120 constituting two complementary strips 112, 122 disposed on two support webs respective 114, 124,</li><li>means 70 adapted for welding a veil 114 of the closure means 100 on the film F at the at least one of said longitudinal edges veil 114, upstream from the forming neck 20, the closure means being F oriented transversely to the longitudinal direction L of the film F (during this step, preferably the two complementary strips 112, 122 are engaged), and</li><li>means adapted to weld the second web 124, means closure 100 on an opposite side of the film F at an edge only said second web 124, downstream of the forming collar 20.</li></ul>

The aforesaid welding means adapted to ensure the weld the second web 124 can be integrated with 50 welding means cross.

The accompanying figures weld lines of the first web 114 on the film F are referenced 115, while the weld line of the second 124 sailing on the film F is referenced 125.

Preferably the closing means are of T sections 100 cut using a cutting tool 80 from a reel in reserve 82 as shown schematically in Figure 1 attached.

The means 60 adapted for routing through sections closing 100 transversely over the film F and welding said means closure 100 thereon, may be subject to numerous variants of production. They can be broadly consistent with the described means in US-A-4,909,017, US Patent 4,617,683, US Patent 4,665,862, US Patent 4,666,536, US Patent 4,878,987 and US-A-4 844 759. However in Preferably these means are essentially consistent with the provisions described in the patent application FR 96 02390 filed Feb. 27 1996 in the name of the Applicant, according to which means Routing 60 comprise a straight guide 62, to the means closing 100, superimposed on the film F, transversely to the latter, designed to precisely positioning the closure means 100 on the film F and Input means 64 or gripping (forceps, needle or suction head) that carry by pulling on the front end of the closure means 100 and not by pushing on the rear end thereof, for conveying the medium closing 100 in the aforesaid straight guide 62. These provisions can guarantee a good table in the straight state of the means 100 closure on the film F.

Thus the closing means T sections 100 and routed welded onto the film F preferably have a length equal to a maximum of half the width of the film F.

Furthermore the closing means T sections 100 are preferably deposited and welded to the film F in a centered position by the width thereof.

In the context of the present invention, the closure means 100 may include two additional sections 112, 122 arranged on separate respective webs 114, 124, as seen in Figures 2 and 4 to 6. However alternatively the sails 114, 124 bearing profiles Additional 112, 122 may be connected as a canvas Joint 130 of U-shaped geometry as seen in Figure 3. In this case, the wire in U 130 may have its convexity directed towards the front or towards the rear in the direction of travel L of the film F. However, in the framework of the present invention, this convexity is preferably oriented the rear.

According to the embodiment shown schematically in Figure 2 and considered as preferred, the first web 114 of the closing means is welded on the film F at its two longitudinal edges, is obtained 115. and an asymmetrical welding of the closure means 100 on the film F, as illustrated in Figure 5, one of the webs 114 being welded by its two longitudinal edges, while the second web 124 is welded only by one longitudinal edge. However alternatively, the first web 114 the closing means 100 may only be welded to the film F on one only of its longitudinal edges. In this case it is preferably the longitudinal edge of the web 114, situated in front with reference to the direction of The movement of the film F, as shown in Figure 4. Thus, the solder 115 114 formed between the veil and the film F prevents décolement the means closure 100 during movement of the film F.

The weld 125 formed on one longitudinal edge only of second veil 124 is itself made on the longitudinal rear edge reference to the moving direction L of the film F, as shown on the Figure 5. This weld 125 is thus placed side mouth of the bag and not the side of the internal volume thereof. Thereby the internal pressure the bag urges the closure profiles 112, 122 toward and not away.

If necessary, the webs 114 and 124 of the closure means 100 may be provided with longitudinal flanges 116, 126 at the edges of the webs 114, 124 to be welded on the film F (it is preferably of beads 116, 126 tapering away of the veil 114, 124, eg generally triangular cross section such as beads Set in the French patent application filed on behalf of the Applicant June 17, 1997 under No. 97 07490 and as shown schematically in Figure 6), or localized layers of material to facilitate the welding of the webs 114, 124 at this level.

The presence of such ribs 116, 126 allows in particular ensure a good bond between the sails 114, 124 and the film F, including default of parallelism between said webs 114, 124 and the film F.

The present invention offers the following advantages:<ul><li>it allows to benefit from a certain tolerance on the position of the solder 115, 125 between the webs 114, 124 of the closure means 100 and the film F, and</li><li>it allows, thanks to the presence of a single weld 125 located on the second veil 124, to generate a leverage effect on the closing means 100 under the effect of the pressure inside the bag, which improves closing the final bag, the internal pressure of the bag urging the two sections 112, 122 in mutual engagement.</li></ul>

The present invention applies in particular to the realization of bags based on film F plastic. However the present invention can apply to the realization of film-based F bags made of any material equivalent, in complex film base comprising in particular a sheet of paper or metal coated with a layer of plastic material.

In the context of the present invention, the support webs 114, 124 profiles 112, 122 of the closure means 100 can be came from molding with their respective profile 112, 122 or be reported thereon.

Moreover geometry complementary profiles 112, 122 may be subject to numerous variants.

Thus, according to the embodiment shown in Figures appended, the profiles 112 and 122 are formed of an element respectively single female and a single male member adapted to penetrate said female member. However alternatively a means can be used closing 100 in which sections 112 and 122 each include several male and female respectively juxtaposed elements, such as described for example in FR-A-2613326.

Where appropriate, the profiles 112 and 122 may also understand, known manner, support ribs or buttresses, preferably arranged laterally on the outside of the male elements and female, to ensure reliable engagement thereof.

In the accompanying figures there is shown a closure means 100 comprising two support webs 114, 124 of a width substantially identical. Alternatively, however, can be provided to use sails carriers 114, 124 of substantially different width. Naturally, the present invention is not limited to the embodiments achieving individuals who have just been described, but extends to all variants within its spirit.

In particular, although there has been illustrated in the accompanying figures a forming machine, filling and closure of vertical type, ie a machine in which the forming throat 20 is disposed vertically, the present invention also applies to a type of machine horizontal, or inclined to the vertical and the horizontal.

Such a horizontal type machine essentially comprises:<ul><li>means for conveying a film F in a longitudinal direction,</li><li>deposit means the product to be packaged, on the film F,</li><li>forming means of the film F around the product,</li><li>means 40 for longitudinal welding and</li><li>means 50 for transverse welding and separating bags.</li></ul>

Furthermore the welding step of the first web 114 of the means 100 closure, the film F can be made on the forming machine, filling and closing bags, immediately upstream of the means forming 20, during a continuous process, or on the contrary, the first web 114 of the closure means 100 can be welded to the film F during a step prior to the implementation of the machine forming, filling and closing machine illustrated in Figure 1, film F thus equipped with the closure means 100 being conditioned before being routed to the forming means 20 of said machine for the implementing the aforementioned method.

Furthermore, in the context of the present invention the pouches obtained can have many characteristics complementary to those described above, such as lines of precut, opening piping or decoration etc ...