This patent application claims priority to European Patent Application No. 21189416.7 dated Aug. 3, 2021, which is incorporated by reference herein in its entirety.
The invention is based on a folding wedge device for a bag packaging machine with a feed area for continuously feeding a flat packaging foil, a discharge area opposite the feed area for discharging the packaging foil folded centrally by means of the folding wedge device, a folding wedge having two folding wedge strips which converge in a wedge shape from the feed area to the discharge area and are intended for deflecting the packaging foil, a counter tip arranged downstream of the folding wedge strips, as seen in the conveying direction of the packaging foil, for inserting a bottom fold between the packaging foil sections folded centrally on top of one another, the folding wedge strips having end sections pointing towards the counter tip. A similar folding wedge is known, for example, from CH 377183 A.
To produce a bottom fold on a packaging bag, format-dependent parts must be provided on the folding wedge in a paired manner. To change the dimensions of the bottom gusset, the size of which determines in particular the contact area of the bag, in previous solutions a format part at the tip of the folding wedge and a counter tip inserting the bottom gusset must be replaced and/or positioned accordingly.
Particularly in the case of frequent changes of bags to be produced with differently formed bottom gussets on a packaging bag machine with folding wedge, however, this exchange or repositioning of the format parts is time-consuming and labor-intensive.
It is therefore the aspect of the present invention to improve a folding wedge in such a way that the production of packaging bags with different bottom fold dimensions is simplified.
Accordingly, it is provided that a lateral distance between the end sections of the folding wedge strips is infinitely adjustable. The packaging foil can be fed to the folding wedge device in a horizontal orientation via the feed area. The feed area may comprise a conveying and/or deflecting roller by means of which the foil web is directed under the folding wedge. The skilled person will recognize that the foil can also be fed in other orientations, and that it is rather the orientations of the feed in relation to the orientation after discharge that is important. In the direction of conveyance of the packaging foil, the folding wedge may have a slope, while the direction of movement of the foil web past the folding wedge may be horizontal. As the foil passes the folding wedges, the foil may first be deflected in the conveying direction at its outer edges into a vertical orientation toward the top of the folding wedge. As the folding wedge strips continue, the deflection can move continuously further towards the center of the foil. If no bottom fold is provided, when the foil web reaches the end of the folding wedge, i.e. when the foil web reaches the end sections of the folding wedge strips, the foil web is folded in the middle, in which case the end sections form a point which is arranged in the folding of the foil web. After passing the end sections of the folding wedges, the foil web leaves the folding wedge, whereby in the case that a bottom fold is provided, the distance between the end sections corresponds to the width of the packaging foil section which is provided for inserting the bottom fold. This packaging foil section stretched by the end sections can then be guided over the counter tip, which inserts the packaging foil section between the opposing vertical packaging foil sections deflected by the folding wedges, thereby creating the bottom fold. In cross-section, the packaging foil may have a W-shape after leaving the folding wedge device through the exit device. The exit device can be formed by two counter-rotating rollers or fixed guide elements, through whose formed gap the superimposed foil is guided and folded. It may be provided that the lateral distance between the folding wedge strips can be continuously adjusted. It can be provided that when adjusting the lateral distance between the folding wedge strips, the lateral distance is adjusted uniformly over the entire extension of the folding wedge strips. Alternatively, the lateral distance between the end sections can be adjusted by rotating the folding wedge strips relative to each other.
It may also be provided that the folding wedge strips are linearly movable along their main extension direction for adjusting the distance between the end sections. The folding wedge strips may be arranged in their original orientation at a predetermined angle to each other. During linear travel along the main extension direction of the folding wedge strips, they may maintain the predetermined angle with respect to each other. It may be provided that the linear travel of the folding wedge strips causes them to be moved relative to the feed section or the feed-out section. It may further be provided that the folding wedge strips are moved relative to the counter tip during linear travel. Thus, it may be provided that the distance between the end sections and/or between the folding wedge strips is increased when they are moved linearly in the direction of the feeding device. Furthermore, it can be provided that the distance between the end sections and/or the folding wedge strips is reduced when these are moved linearly in the direction of the feed-out device and/or the counter tip.
It is possible that the folding wedge device has a carrier plate on which linear guides, for example guide rails or a carriage, are mounted for adjusting the folding wedge strips. Alternatively, it is possible that the guide rails are mounted on the folding wedge strips. The linear guides can enable linear adjustment of the folding wedge strips relative to the carrier plate.
It is also conceivable that the folding wedge strips can be adjusted by motor by means of a drive, in particular a spindle drive, arranged in particular between the folding wedge strips. Alternatively, it is possible for each folding wedge strip to have a separate drive. In the embodiment of a common drive, this can have a center guide which can be moved by the drive along the conveying direction of the packaging foil. In contrast, the directions of movement of the folding wedge strips can each be at an angle to the conveying direction and parallel to the conveying plane. However, it can be provided that the folding wedge strips each have a movement component which extends along the conveying direction of the packaging foil. The directions of movement of the folding wedge strips can be mirror-symmetrical with respect to the conveying direction of the packaging foil. The center guide can in each case have lateral drivers which are set up to move the opposite folding wedge strips along their respective path of movement.
It can be provided that the folding wedge strips can be moved in the direction of the lead-out area to reduce the distance between the end sections. Due to their V-shaped or wedge-shaped alignment to each other, the distance between the end sections can be reduced when the folding wedge strips are moved in the direction of the lead-out area. Therefore, the lateral distance between the folding wedge strips can be reduced from the feed area in the direction of the feed-out area.
Accordingly, it can be provided that the folding wedge strips can be moved in the direction of the feed area to increase the distance between the end sections.
In addition, it can be provided that the counter tip has two counter tip strips converging towards each other in a wedge shape in the conveying direction of the packaging foil for inserting the bottom fold. While the foil is guided along an underside of the folding wedge and the folding wedge strips have corresponding deflection edges pointing towards the underside of the folding wedge, the packaging foil, on the other hand, is guided along the upper side of the counter tip in order to insert the bottom fold between the side walls of the bag, so that the deflection edges of the counter tip strips have corresponding deflection edges pointing towards the upper side of the counter tip.
In particular, it can be provided that the folding wedge and the counter tip are aligned with each other in such a way that the end sections of the folding wedge meet the counter tip obliquely in a contact area, preferably forming a foil gap of 0.1-2 mm, preferably 1 mm, with the latter. The contact area can be line-shaped. This may provide for the folding wedge tip to abut a surface of the counter tip. It may be provided that the counter tip ridges of the wedge-shaped counter tip have a spacing at a portion of the counter tip which corresponds to the maximum adjustable spacing of the end portions of the folding wedge ridges. It can also be provided that the mating point strips of the wedge-shaped mating point have a distance at a section of the mating point which corresponds to the minimum adjustable distance of the end sections of the folding wedge strips.
It may further be provided that the angle between the folding wedge and the counter tip is approximately between 100° and 140°, preferably between 110° and 130°.
It can be provided that the counter tip is height-adjustable, in particular motor-driven. This means that when the end sections of the folding wedge strips are adjusted, the counter tip can be tracked so that the contact area or the foil gap between the end sections of the folding wedge strips and the counter tip can always be set to a constant value, irrespective of the setting of the bottom fold dimension. Thus, when the bottom fold is increased, the distance between the end sections of the folding wedge strips can be increased and the folding wedge strips can be adjusted accordingly in the direction of the feed device. The resulting increase in the foil gap can thus be counteracted by adjusting the counter tip upwards. When setting a smaller bottom fold, this process can be carried out accordingly in reverse order. Alternatively, the counter tip can be adjusted along the conveying direction.
Thus, it can be provided that the counter tip is adjusted downward to reduce the bag fold dimension.
Accordingly, it may be provided that the counter tip is adjusted upward to increase the bag fold dimension.
It can also be provided that the folding wedge device has a control device which is set up to control the drive device of the folding wedge strips and the drive of the counter tip in such a way that, when the size of the bottom fold is set, the end sections of the folding wedge strips are each aligned with the counter tip strips in such a way that the lateral distance between the folding wedge strips essentially corresponds to the lateral distance between the counter tip strips in the contact area. At the same time, the control device can control the drives so that a constant foil gap is formed between the end sections of the folding wedge strips and the counter tip, regardless of the set bottom fold dimension.
Furthermore, it can be provided that the folding wedge has an additional, in particular motor-driven, adjustable guide strip to support the packaging foil between the end sections of the folding wedge strips. This can prevent wrinkling of the foil in this area. The guide strip can be arranged in such a way that it rests against the foil gap and helps to form it. The tracking of the foil strip when adjusting the bottom fold dimension can be oriented to the adjusted folding wedge strips so that it is aligned in the conveying direction at the height of the end sections in each case.
Provision may be made for the packaging foil to extend in front of the feed area substantially perpendicular to the packaging foil behind the feed-out area.
Further details of the invention are explained with reference to the figures below. Thereby shows:
The folding wedge device 1 shown in
The cross-sectional view of a folding wedge device 1 shown in
The features of the invention disclosed in the foregoing description, in the drawings as well as in the claims may be essential to the realization of the invention both individually and in any combination.
Number | Date | Country | Kind |
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21189416.7 | Aug 2021 | EP | regional |