NL1031167C2 - Device for joining strips of plastic foil material together. - Google Patents

Description

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Brief description: Device for joining strips of plastic film material together.

DESCRIPTION

The invention relates to a device for connecting strips of plastic film material to each other for obtaining at least one foil seam comprising supply means for guiding the two overlapping strips of film material to a connecting position, as well as connecting means formed by at least one assembly consisting of at least one assembly consisting of at least one stamp element and anvil element, which at least one stamp element and at least one anvil element are arranged on either side of the connecting position and can be placed against each other for the formation of the at least one filament seam.

Such a device is generally known and is used in the packaging industry, wherein products must be packaged or encased with foil material. In such an application, one or two strips of foil material are wrapped around the product in an automated process, whereafter the two overlapping strips of foil material are connected to each other at the location of a connecting position with the aid of per se known connecting means, for example by means of a heating wire. in the establishment.

A drawback of the currently known devices is that for manufacturing a filament seam between the two strips of film material, the stamp element forming part of the connecting means and anvil element cooperating therewith have such a structural length dimension that the quality of the filament seam to be applied and in the in particular the adhesion over the full length of the film seam between the two strips of film material is of a reduced quality. This is in particular dictated by film seams of a considerable length where the stamping element and anvil element which can be placed against each other deform for example under the influence of gravity and thus do not fit well together, seen over the full length of the film seam to be applied.

Not fully connecting the anvil element and the stamp element to each other as a result of deformation or sagging results in a localized seam with a weak adhesion or, in the worst case, the absence of an adhesion between the two strips of film material. The

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Foil seam thus realized has a reduced quality which, due to the poor adhesion between the two strips of film material, can come loose on site. Moreover, a non-connection or bonding of the two strips of film material on site results in a "leaky" film seam, which is undesirable in the case that the product in question must be packaged airtightly in the film material.

The invention has for its object to obviate the above-mentioned drawbacks and to provide a device as described in the preamble with which improved film seams can be provided between the film material, which strips of film material are interconnected over the entire film seam length, so that the film seam thus obtained is not only stronger and therefore less. releases quickly, but above all is completely closed without 'leaky', non-interconnecting strips of foil material.

According to the invention, the device is characterized in that abutment means are provided which, for the purpose of forming the at least one foil seam, fully overlap the entire length of the foil seam 15 to be formed and promote the at least one stamp element and the at least one anvil element. Thus, a possible deformation of the connecting means over the length of the foil seam to be formed is compensated (and / or counteracted) and a fully closed foil seam between the two strips of foil material will be realized, which foil seam will not only be stronger but also releases less quickly.

More specifically, the abutment means form part of the at least one stamp element and / or the at least one anvil element, where in a special embodiment the abutment means comprise a plurality of magnets arranged over the full length dimension of the at least one stamp element and / or the at least one anvil element .

As a result, a good connection that can be realized over the full length and therefore clamping of the strips of foil material can be obtained, which benefits the quality and strength of the foil seam to be formed. The clamping of the two strips of film material is thereby reproducible through the use of magnets and constant and equal over the entire seam length, which makes it possible to form successive film seams of corresponding quality. Furthermore, a clamping of the strips of film material is achieved with an identical clamping force that is constant over the entire seam length, so that the film seam to be formed does not have any weak points over the entire length.

In particular, in one embodiment the at least one stamp element and the at least one anvil element have a length dimension at least equal to the length dimension of the foil seam to be formed.

The quality of the foil seam to be formed, at least over its entire length, is further guaranteed in that the at least one stamp element can be moved against a reset force against the at least one anvil element. As a result, a constant clamping of the two strips of film material, seen over the length of the film seam, is achieved, which results in a film seam without weak points.

In a specific embodiment, the at least one stamp element is placed on a support that can be moved along a guide.

A spring element supporting the support carrier can be arranged around the guide.

According to a special embodiment of the device according to the invention, the at least one stamp element and the at least one anvil element are adapted to form two foil seams running parallel to each other. The at least one stamp element can herein be composed of two stamp element parts running parallel to each other.

More specifically, a cutting element can be placed between the two stamp element parts. In this way, two foil seams located parallel to each other can be formed in one operating pass, which can moreover be separated from each other in the same operating pass.

To this end, the at least one anvil element is composed of two anvil element parts running parallel to each other and co-operating with corresponding stamp element parts, wherein an abutment element cooperating with the cutting element can further be placed between the two anvil element parts.

To improve the quality of the film seam to be formed, each anvil element part is composed of a clamping element for clamping in the two strips of film material and a seam-forming element for forming the film seam.

The seam-forming element can herein be provided with a filament.

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The invention will now be explained in more detail with reference to a drawing, which drawing successively shows in: figure 1 a view of an embodiment of a device according to the invention; Figure 2 shows an enlarged view of the connecting means according to the invention; figure 3 shows another enlarged view of the connecting means according to the invention.

For a better understanding of the invention, in the following description the corresponding parts of the device according to the invention will be indicated in the accompanying figures with identical reference numerals.

Figure 1 shows an embodiment of a device 10 according to the invention for joining two strips of foil material 8a-8b (see figure 3) to obtain a foil seam.

Such a device is used in particular for encapsulating various products 5-5'-5 '' with the aid of strips of foil material, which can be added to a connecting position 6 in the device 10 by means of specific supply means 20.

In this embodiment, products 5-5'-5 "can have considerable dimensions and consist, for example, of boxes. These products 5-5'-5" are fed via a work surface 11 to the binding position 6 on the basis of the means 20 which consist of an endless carrier 21 which is guided over rollers 22a-22b, and wherein the roller 22a is drivable by means of a drive unit 23 known per se, for example an electric motor. With the aid of a pushing element 24 provided with a pushing surface 25, which can be moved to the connecting position 6 with the aid of the endless carrier 21, the product 5-5'-5 'to be enveloped by means of foil material is introduced into the device wherein foil material is wrapped around the product is applied.

In order to connect the foil material wrapped around the product 5-5'-5M, connecting means 30 are provided at the location of the connecting position 6. The connecting means 30 are thereby formed by at least one assembly consisting of at least one punch element 31 and an anvil element 32 , which are arranged on either side of the connecting position 6 and can be moved from and to each other with the aid of suitable displacement means.

In this embodiment, the stamp element 31 is accommodated in the device 10 for displacement. To this end, conductors 33 are included in the device, between which the stamp element 31 is arranged so as to be movable. With the aid of suitable displacement means, for example an endless carrier 34 which is arranged over two or more rollers 35a-35b, and wherein the roller 35a is drivable by means of a drive unit 36 (e.g. an electric motor) known per se, the stamp element 31 can be moved from and to the anvil element.

When the stamp element 31 is displaced in the direction of the anvil element 32, the strips of film material 8a-8b included between them are pressed against each other and fused together for example with the aid of heat to obtain a film seam.

As Figure 2 already discloses, the connecting means 30 and in particular the stamp element 31 and the anvil element 32 can have a considerable structural length dimension. A drawback with this known construction is that the stamp element 31 and / or the anvil element 32 can sag and therefore deform under the influence of their weight and gravity. As a result, over the full length (which corresponds to the film seam length to be applied) an insufficient connection of the stamp element 31 and the anvil element 32 is found, so that also the two strips of film material 8a-8b are insufficiently compressed against each other and the otherwise realized film seam is reduced. possesses quality and can easily come loose. Above all, there is a risk with the existing constructions that the two strips of film material do not fully connect with each other when the film seam is applied, so that a "leaky" film seam 25 is created.

In the embodiment as shown in Figure 2, the stamp element 31 is displaceable from and to the anvil element 32 stationarily arranged. For this purpose (see also figure 3) the stamp element 31 comprises a beam 310 which is movable with its end 310a-310b along the guide 33 of the device 10 (see also figure 1). The displacement of the beam 310 takes place on the basis of the displacement means 34-35a-35b-36 shown in Figure 1.

As shown, the connecting means 30 are composed of two assemblies, each consisting of a stamp element 311a and 311b and an anvil element 321a and 321b, respectively. With this construction, c * 6 makes it possible to simultaneously install two separate film webs in separate strips of film material. However, it will be clear that also an embodiment of the device according to the invention is possible, wherein the connecting means 30 only have one stamp element 311a and one anvil element 321a.

According to the invention, the device is provided with abutment means 50 which, for the purpose of forming the film seam between the strips of film material, ensure that the stamp element 31 and the anvil element 32 abut against each other over the entire length of the film seam to be formed. abutment means 50 consist of magnets which are arranged over the full length (longitudinal direction) of the anvil element 32. The magnets 50 can also be placed on the stamp element 31 in a similar manner.

As shown in the detailed embodiment of Figure 3, the abutment means that ensure a complete abutment of the stamp element 31 and the anvil element 32 (over the full length of the foil seam to be applied) become from magnets 50, which in this embodiment form part making the anvil element 32. However, in another embodiment the abutment means 50 can also form part of the stamp element 31.

Preferably, and as shown in Figure 2, the stamp element 31 is composed of a thin, flexible strip 315, which is slightly deformable and therefore when the stamp element 31 is placed at the location of the connecting position 6 against the anvil element 32 under the influence of the abutment magnets 50 forms to the contour of the possibly deformed anvil element 32.

By the flexible, deformable strip 315 and the magnets 50 (which are arranged either in the anvil element 32 or in the stamp element 31 or in both parts) a strip along the entire length of the foil seam to be arranged is abutting against the strip 315 anvil element 32 is realized, so that the foil seam to be formed thus has an improved quality.

Because the magnets exert a constant magnetic force between the stamp element 31 and the anvil element 32, the strips of film material 8a-8b clamped between the two parts are pressed against each other over the full length of the film seam to be applied. This creates a foil seam closed over the entire length, without weak or “leaky” 7 spots.

However, it is also possible - depending on the material properties of the foil material used (such as thickness, strength or softening temperature) - not to fit the abutment magnets 50 as permanent (natural) magnets, but as electromagnets. In the latter - controllable - version, the magnetic force with which the punching element is pressed against the anvil element can be adjusted (or "pulled in") and thus the quality (or strength) of the shaping seam to be formed. For example, the magnetic force can be adjusted over the entire length of the thread to be applied (constant, or seen as variable over the length of the thread).

As shown in Figure 3 (and partially in Figure 2), the anvil element 32 is placed on a beam 320, which orientates the anvil element 32 stationarily in the device 10. The anvil element 32 placed on the girder 320, together with the stamp element 31 arranged on the movable girder 310, is adapted to form two film seams running parallel to each other in the strips of film material 8a and 8b, respectively. To this end, the punch element 31 is composed of two stamp element parts 311a, 311b, which run parallel to each other. A cutting element 316 is included between the two stamp element parts 311 a-311 b.

As already indicated above, the elongated strip element 315a-315b has a length at least equal to the film seam to be provided between the two strips of film material 8a-8b. Accordingly, each stamp element part 311 a-311b has one or more support carriers 313 on which the elongated strip element 315a-315b is mounted. The different support carriers 313 are displaceable along a guide 314. As a result, the elongated strip 315a-315b can form towards the contour of the (deformed) anvil element 32.

Thus, an adequate connection of the strips 315a-315b to the support element 32 can be realized over the full length of the film seam to be applied between the strips of film material 8a-8b. As a result, the strips of film material 8a-8b are pressed against each other over the full length of the foil seam to be applied and a fully closed foil seam is thus provided with a uniform strength, which foil seam cannot easily be released and certainly no weak or "leaky" paste.

Analogously to the construction of the punch element 31 which is constructed from different stamp element parts 311a-311b from C8, according to the invention the anvil element 32 is also constructed correspondingly from two anvil elements 321a-321b located parallel to each other. More specifically, each anvil element 321a-321b is composed of a clamping element 322a and 322b, for clamping the strips of film material 8a-8b with a clamping surface 325a-325b against the strip 315a forming part of each stamp element part 311 a-311b -315b.

In addition, each anvil element 321a-321b is provided with a seam forming element 323a and 323b cooperating with the respective clamping element 322a-322b, which also clampes the two strips of film material 8a-8b between the strips 315a-315b and by means of heat, for example by means of a heat wire 324a-324b arranged in the longitudinal direction, affixing the foil seam. However, other possibilities for applying the foil seam with the aid of heat are also possible, for example with the aid of ultrasonic sound.

The function of the two clamping elements 322a-322b is to orient and / or fix the two strips of film material 8a-8b relative to each other and relative to the seam forming elements 323a-323b in order to shift or loosen the strips of film material and to apply a correspondingly incorrect 20 of the foil seam.

In Figure 3, the heat wire with which the film seam is applied between the strips of film material 8a-8b is indicated by the reference number 324a-324b, while the clamping surface of the clamping elements 322a and 322b is indicated by the reference number 325a-325b.

As already explained above, each stamp element 31 is placed on a support carrier 313 movable along a guide 314. This displacement of the stamp element 31 takes place against a restoring force, which may for instance consist of a spring element 317 arranged around the guide 314 and supported between the support 313 and the beam 310 which is more or less part of the fixed world (but can be moved in the device).

For the purpose of applying the film seam between the strips of film material 8a-8b, the girder 310 is moved by means of the displacement means 34-35a-35b-36 along the guides 36 in the device 10 to the anvil element 32 fixedly arranged in the device 10 . The two foil materials 8a-8b fired are thereby clamped between the strips 315a-315b and the corresponding clamping elements 322a-322b and the seam-forming elements 323a-323b. After applying two foil seams running parallel to each other (namely the foil seam for enclosing film material 5 around a product 5 and applying the starting seam for the following product 5 '), the girder 310 becomes a further displacement in the direction of the anvil element 32.

The two stamping element parts 311a-311b will thereby move against the spring force of the spring element 317 along the guide 314. The cutting element 316 then moves in the direction of the strips of film material 8a-8b and will cut it between the applied film seams A-B at the location of the letter C. For this purpose a stop element 326 is arranged between the two anvil element parts 321a-321b. Subsequently the beam 310 is moved upwards in the device 10 so that the stamp element is moved away from the anvil element 32. In this way, space is created for discharging the product 5 which is now encased in foil material connected at the location of the foil seam B.

The strips of film material 8a-8b connected to each other at the location of the film seam A can now be applied around the following product 5 '. In a subsequent operation, the beam 310, together with the stamp element 31, is moved downwards in the direction of the anvil element 32 for arranging an end seam B (for product 5 ') and a starting seam A (for the following product 5) in one operating step. Here too, the two foil seams A and B are separated from each other with the cutting element 316.

When the beam 310 with the stamp element 31 is moved upwards again, the two stamp element elements 311 a-311 b will move back along the guide 314 under the influence of the compressed spring element 311, so that the cutting element 316 '' retracts '' between the both stamping element parts 311a-311b and the respective stamping strips 315a-315b.

It will be clear that with the aid of this device wherein each stamp element 31 abuts the anvil element 32 by means of magnets 50 along the entire length of the foil seam to be applied, foil seams of a homogeneous, stable quality can be obtained without the presence of weak or 'leaky' spots.

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Claims (14)

Device for connecting plastic film material to each other for obtaining at least one film seam comprising supply means for guiding the two overlapping strips of film material to a connection position, as well as connection means formed by at least one assembly consisting of at least one stamp element and anvil element, which at least one stamp element and at least one anvil element are each arranged on either side of the connecting position and can be placed against each other for forming the at least one foil seam, characterized in that the at least one stamp element or the at least one anvil element is designed as a flexible , elongated element and wherein abutment means are provided which, for the purpose of forming the at least one foil seam, have a complete abutment along the entire length of the foil seam to be formed of the at least one stamp element and the at least one anvil element such that the flexible, elongated element thereby follows the contour of the at least one anvil element or the at least one stamp element. 2. Device as claimed in claim 1, characterized in that the abutment means form part of the at least one stamp element and / or the at least one anvil element. 3. Device as claimed in claim 1 or 2, characterized in that the abutment means comprise a plurality of magnets arranged over the full length dimension of the at least one stamp element and / or the at least one anvil element. Device as claimed in claim 3, characterized in that the at least one stamp element and the at least one anvil element have a length dimension at least equal to the length dimension of the foil seam to be formed. 5. Device as claimed in one or more of the foregoing claims, characterized in that the at least one stamp element is displaceable against a restoring force against the at least one anvil element. 1031167 Device as claimed in claim 5, characterized in that the at least one stamp element is placed on a support carrier displaceable along a guide. 7. Device as claimed in claim 6, characterized in that a spring element supporting the support carrier is arranged around the guide. Device as claimed in one or more of the foregoing claims, characterized in that the at least one stamp element and the at least one anvil element are adapted to form two foil seams running parallel to each other. Device as claimed in claim 8, characterized in that the at least one stamp element is made up of two stamp element parts running parallel to each other. Device as claimed in claim 9, characterized in that a cutting element is placed between the two stamp element parts. Device as claimed in claim 9 or 10, characterized in that the at least one anvil element is made up of two anvil element parts running parallel to each other and cooperating with corresponding stamp element parts. 12. Device as claimed in claim 11 in combination with claim 10, characterized in that a stop element cooperating with the cutting element is placed between the two anvil element parts. 13. Device as claimed in claim 11 or 12, characterized in that each anvil element part is composed of a clamping element for clamping in the two strips of foil material and a seam-forming element for forming the foil seam. Device as claimed in claim 9, characterized in that the seam-forming element is provided with a filament. 1031167 30