Patent Application
20090317151
The present invention relates to a feeding and fixing apparatus for feeding and fixing a functional element to a sheet of film according to the features of the precharacterizing clause of claim 1.
Feeding apparatuses and fixing apparatuses for feeding and fixing a functional element, such as a closure element, to a sheet of film are known from the prior art. The sheet of film is used to produce a bag pack, such as a folding bag, a stand-up bag, etc. In this case, the closure element is used to close an opening through which the product in the bag can be removed.
Such apparatuses are known from the prior art. For instance, WO99/03672 shows an apparatus for fitting a closure element to a bag. In this case, the apparatus comprises a roll having a plurality of holding devices for holding a closure element. The roll is placed under and transversely with respect to the sheet of film and feeds a closure element to the sheet of film by means of a rotary movement.
The disadvantage in the case of apparatuses of the prior art is the fact that the sheet of film with the closure elements already fixed thereto can be processed further only with difficulty. In particular, it is difficult to carry out appropriate folding operations with the sheet of film.
Starting from this prior art, the invention is based on the object of specifying an apparatus mentioned at the beginning which overcomes the disadvantages of the prior art. In particular, an apparatus is to be specified which permits a functional element to be fixed to an already folded sheet of film.
This object is achieved by a feeding and fixing apparatus having the features of patent claim 1. Accordingly, a feeding and fixing apparatus for feeding and fixing a functional element to a sheet of film comprises a feed unit for holding a functional element. The feed unit comprises at least one holding device for holding the functional element, the at least one holding device being arranged substantially parallel to the sheet of film and, by means of a pivoting movement, being capable of being positioned in the region of the sheet of film in a plane running parallel to the sheet of film.
As a result of the pivoting movement of the feed unit and the holding device, the attachment of a functional element in the sheet of film is made possible. In this case, the holding device with the functional element is moved from a location outside the sheet of film to a location inside the sheet of film via a pivoting movement.
The feed unit preferably also comprises a feed plate, the at least one holding device being connected to the feed plate, and the surface of the feed plate being substantially parallel to the sheet of film. The feed plate preferably has the shape of a circular disc and, for example, can be built up from a number of parts. Alternatively, it is also possible for the feed plate to be constructed as a circular segment. The feed plate is preferably arranged in such a way that parts of it are located in the region of the sheet of film before, during and after the pivoting operation.
The feed plate or the holding device can preferably be pivoted about an axle which is substantially perpendicular to the sheet of film.
The sheet of film is preferably a folded sheet of film, this being folded in such a way that the feed plate or the at least one holding device can extend or project into the folded sheet of film.
At the time at which the functional element is joined to the sheet of film, the holding device is preferably either at right angles to the transport direction or at an angle to the transport direction.
The functional element is preferably a closure element, a re-closable closure element, a guarantee element, a viewing window or a reinforcing element.
Preferably, the apparatus further comprises a Joining unit for joining the functional element to the sheet of film.
The holding device preferably comprises at least one vacuum nozzle which provides a vacuum, so that the functional element is held on the holding device. The vacuum nozzle can be formed in different ways. Use is preferably made of an elongated vacuum nozzle or a plurality of individual vacuum nozzles which are arranged at a distance from one another.
The holding device further comprises at least one section which provides an increased frictional force between functional element and holding device, the section being made of a plastic chosen from the group of elastomers, such as silicone. This section preferably surrounds the vacuum nozzles. Therefore, the functional element can be held by the vacuum nozzles in its central region and rests with the other regions on the plastic.
Preferably, at least two holding devices are arranged at a distance from each other, the angle between adjacent holding devices being equal, and it being possible for a holding device to be loaded with a functional element, and it being possible for the functional element from another holding device to be joined to the sheet of film at the same time.
In a method for feeding and fixing a functional element to a sheet of film, using an apparatus which comprises a feed unit for holding a functional element and a joining unit which produces a connection between the sheet of film and the functional element, by means of a pivoting movement, the functional element is positioned in the region of the sheet of film in a plane running parallel to the sheet of film and, after the pivoting movement, the functional element is joined to the sheet of film.
Further advantageous embodiments are characterized in the subclaims.
Preferred embodiments will be described in more detail by way of example below by using the drawing, in which:
a, b show a detail view from
With reference to the drawings, possible exemplary embodiments will be described. The drawings and the description show preferred exemplary embodiments and are not intended to be interpreted to restrict the invention, which is defined by the claims.
A functional element 11 is generally understood to mean an additional element which is to be joined to the sheet of film 10. In particular, a functional element 11 is understood to mean a closure element, a re-closable closure element, a guarantee element, a viewing window or a reinforcing element. The expression closure element used below includes the elements just mentioned. A closure element 11 is understood, for example, to mean a zip fastener or a similar element. The closure element 11 is in this case designed to be re-closable and can include a guarantee element which is destroyed at the time of first opening.
A pre-folded sheet of film 10 is to be understood to mean a continuous film for the production of a bag. The pre-folded sheet of film comprises a left-hand side fold 14, a right-hand side fold 15, an upper side 16 of the sheet of film and an underside 17 of the sheet of film. Seen in cross section, the upper side 16 of the sheet of film and the underside 17 of the sheet of film lie substantially parallel to each other and are joined either by the left-hand side fold 14 or by the right-hand side fold 15, so that at least one interspace 18 is produced, through which parts of the apparatus can project. The left-hand side fold 14 and the right-hand side fold 15 can be c-shaped, v-shaped in cross section or bellows-like with a plurality of folds. Other forms are also conceivable. In this case, the sheet of film 10 is subdivided in the direction of the transport direction T into a plurality of sections 12. Each of these sections 12 represents a bag to be produced. In each case, a closure element 11 is provided for each section 12. In a following item of equipment, the strip of film can then be cut along the cut lines 13 in order to finish the bag.
The feeding and fixing apparatus 1 according to the invention substantially comprises a feed unit 2 for holding a closure element 11 and an optional joining unit 3, which produces a connection between the sheet of film 10 and the closure element 11. Furthermore, the apparatus 1 can optionally comprise a loading apparatus 4, which loads the feed unit 2 with the closure elements 11. The elements described in this section will be described below.
The feed unit 2 substantially comprises a feed plate 20 and at least one holding device 24 connected to this feed plate 20. The holding device 24 is used to accommodate and to hold the closure element 11 during the feeding operation and the joining operation. The feed unit 2 or the feed plate 20 and the sheet of film 10 are located in relation to one another in such a way that the sheet of film 10 runs substantially parallel to the feed plate 20.
In the present exemplary embodiment, the feed plate 20 is formed as a disc having a circular basic shape. Here, a disc is understood to mean a cylindrical body having a diameter which is many times greater than the height of the body. It is important that the feed plate 20 has the lowest possible height or thickness, so that it is able to project into the pre-folded sheet of film 10. The thickness is preferably between 10 mm and 50 mm. The disc or the feed plate 20 is bounded at the top and bottom by an upper side 22 and an underside 23. The feed plate can be pivoted or rotated about a shaft 21, which is joined to the underside 23. The shaft 21 can also be described as an axle 21, since it extends centrally through the disc. The axle 21 is preferably arranged with respect to the sheet of film 10 so that it is outside the same. The ability to pivot or rotate is shown by the arrow D in
This means, in other words and expressed in a general form, that the closure element is moved by means of a pivoting movement from a first position which, seen from above, lies outside the sheet of film 10, into a second position, the second position lying inside or in the region of the sheet of film 10. In this case, the pivoting movement runs in a plane which extends parallel to the surface of the sheet of film 10, that is to say parallel to the upper side 16 of the sheet of film. Apart from the advantages with respect to speed and easier adjustability, the pivoting movement also has the advantage that the closure elements can be arranged in a simple way at an angle to the transport direction T and thus also to the bag being produced, if this is desired.
In alternative embodiments, it is conceivable, for example, for the feed plate 20 to be formed as a segment of a disc, so that a part of the feed plate 20 is always located in the sheet of film.
In the present embodiment, the at least one holding device 24 is let into the feed plate 20 via the upper side 22. In this case, the upper side of the holding device 24 is preferably flat or level with the upper side 22 of the feed plate 20. Alternatively, the holding device 24 can also be let into the feed plate 20, so that when the closure element 11 is joined to the holding device 24, this is level with the upper side 22 of the feed plate 20.
A plurality of holding devices 24 are preferably provided. In the present embodiment, four holding devices 24 are provided. Alternatively, two, three, five, six or more holding devices 24 can be provided. However, the number is of secondary importance, more important is the uniform distribution of the holding devices 24 on the feed plate 20. A uniform distribution is understood to mean that the angle between two adjacent holding devices 24 is always the same. It is also possible to state that a plurality of incremental regions are arranged on the feed plate 20, in each case a holding device 24 being arranged in each of these incremental regions. In this case, the feed plate 20 is pivoted by one increment in each case per cycle, as described below. In the embodiment shown in
The holding device 24 is shown schematically in
Alternatively, the vacuum nozzle can also be formed as an elongated channel which extends in the direction of the holding device 24. Such an embodiment is shown in
In an additional embodiment, it is additionally conceivable for the vacuum nozzle(s) 25 to be arranged at a lower level than the region 26. In this case, the closure element or functional element rests only on the region 26 but not on the vacuum nozzle(s) 25.
In summary, it is possible to state that the region 26 can function as a seal between the functional element 11 and the vacuum nozzles, as a damper between the holding device 24 and the joining unit 3 and also as a friction-increasing element between functional element 11 and holding device 24.
In
As can be seen in
It is a particular advantage if the closure element 11 in the case of an already previously folded sheet of film 10 can be fitted in the interior of the same, since the folding of a sheet of film after the fitting of a closure element is problematic and not reliable with regard to accuracy and efficiency. In particular, it should be pointed out here that this type of fitting can be achieved by the provision of the feed plate 20 projecting into the sheet of film 10 and the holding elements 24 projecting into the sheet of film 10 and their pivoting movement.
The feed plate 20 and the sheet of film 10 are positioned in relation to each other in a direction Z, which is perpendicular to the transport direction T and to the axle 21, in such a way that the holding device 24 or the closure element 11 comes to lie in the desired position relative to the sheet of film 10. The desired position preferably lies in the centre of the upper side 16 of the sheet of film with respect to the direction Z.
The joining unit 3 is arranged physically in such a way that this comes to lie over the position at which the closure element 11 is to be joined to the sheet of film 10. The joining unit 3 is preferably a welding device, which produces a welded connection between the surface directed towards the interior of the sheet of film 10 and the closure element 11. If the closure element is, for example, self-adhesive, then the joining unit 3 can also be formed as a plunger which presses the sheet of film 10 against the closure element 11. Such a joining unit 3 can be moved against the strip of film 10 via appropriate actuators, such as pneumatic cylinders 31. In this case, the pneumatic cylinder 31 is joined to a stationary element 32. Alternatively, it is also conceivable for the joining unit 3 to be arranged as close as possible to the upper side 16 of the sheet of film, and for the holding device 24 or feed plate 20 to move against the joining unit 3.
In a further embodiment, it is additionally conceivable to arrange the joining unit 3 in an apparatus positioned downstream. In this case, the closure element 11 can firstly alternately be fitted by the feeding apparatus, for example via an adhesive, while the joining unit 3 produces the connection between the sheet of film 10 and the closure element 11 at a later time.
In
With the aid of
Here, the progress of a cycle appears as follows. In a first step, the strip of film 10 and the feed unit 2 are moved in the corresponding direction D and T, respectively. In the process, the holding device 24 is pivoted into the fixing position, so that it is located underneath the sheet of film 10. In
Furthermore, during the predetermined time, the holding device 24 which is located in the region of the loading device 4 is loaded with a closure element 11. In
In
If the cycle time remains constant, the speed of the strip of film 10 additionally determines the physical length of a section 12 of a bag in the transport direction T. The higher the speed of the strip of film 10, the longer the section 12 of the bag becomes.
The feed plate 20 is driven by the axle or shaft 21 by means of an electric drive, such as by a servo motor, in such a way that this is able to execute the cyclic movement described above. Furthermore, feed lines to the vacuum nozzles 25 are laid via the shaft 21, so that the corresponding vacuum can be provided.
In
Alternatively, and given an appropriate configuration of the holding device 24 as bar-like elements, it is also possible to dispense with the arrangement of the segment element 27. In this case, the bar-like elements are likewise formed with a low thickness, as was described above in connection with the disc. However, it should be noted that the segment elements 27 are advantageous and, for example in the case of non-dimensionally stable films, are to be preferred, since the sheet of film always rests on the feed plate.
In an alternative embodiment that is not shown, it is additionally conceivable for the holding device 24 to be oriented downwards, the vacuum nozzles holding the closure element 11 on the feed plate counter to the force of gravity. In this embodiment, the joining unit 3 then moves from bottom to top. Such an embodiment has the advantage that the closure elements 11 can be provided by means of a conveyor belt, the vacuum nozzles taking the closure element 11 from the conveyor belt.
| Number | Date | Country | Kind |
|---|---|---|---|
| 00962/08 | Jun 2008 | CH | national |
