EP0587989B1 - Device for feeding a (tubular) foil for a hood making device - Google Patents

Description

The invention relates to a (tube) film feed device for a hood formation and, if applicable, covering device, with a film supply wound onto a supply roll and at least one (generally several, generally designed as a guide roller or guide roll), by means of which the film on the way from the supply roll to the hood forming device is essentially in the middle.

Such film feeders are used in packaging technology wherever general cargo, in particular cuboidal piece goods stack, with (at least) a film hood to be wrapped to form a transport-secured and protected against weather influences loading unit.

Thereby i. a. Foil tube material is used, preferably a so-called side-gusseted tube, which consists of two side faces parallel to one another and side gussets folded in a V-shape between these side faces. Such a gusseted tube, which is used in both the shrinking technology and the stretching technology, is opened after being fed to the hood forming device from its flat storage and feeding state (“stretched”) and pulled over the piece goods to be wrapped, i. a. Even before covering the hose, its free end is provided with a transverse weld seam at a distance and is cut off above the formed transverse weld seam, so that a hood is formed. With shrink technology, the stretched side gusset tube or the hood formed from it has an oversize in relation to the cross-sectional area of the piece goods to be encased and, after exposure to heat and corresponding shrinkage, attaches itself firmly to the piece goods to be encased, while it stretches open in stretch technology Has undersize in relation to the cross-sectional area of the piece goods to be wrapped, accordingly stretched (at least) horizontally ("stretched") before being pulled over and pulled over the piece goods to be wrapped with stretched oversize. If the hose / hood is released afterwards, the stretch film hood attaches itself to the piece goods to be wrapped due to the stretch.

In all cases, the tubular film material of the hood forming device is provided by a film feed device supplied, which (if necessary partially) can also be an integral part of the hood formation device.

There is a requirement that the film tube is fed to the piece goods to be wrapped or already to the hood-forming device very precisely in the center, since eccentric feeding can lead to operational difficulties and inadequate wrapping. It has been shown that even relatively small deviations from the desired central feed have corresponding disadvantageous consequences.

An inaccurate feeding of the tubular film material results, however, i. a. even if the supply roll is aligned very precisely in the center of the general cargo position, if only because the tubular film i. a. can not (at least not economically) reel in such a way that the longitudinal edges of layers lying one above the other are exactly aligned with one another, that is to say the end faces of a film supply roll each form a flat surface. Rather, the edges or edge sections of the coiled film layers protrude inwards or outwards beyond the ideal geometrical end face. The consequence of this is that the film runs off the supply roll with a corresponding lateral offset and in this state reaches the film guides, of which i. a. there are several.

This problem has so far been countered by designing or arranging at least one film guide, preferably designed as a guide roller or guide roller, in such a way that its longitudinal axis can be pivoted relative to the central axis of the supply roll by means of suitable devices, in order in this way to correct the film running direction and ultimately an exactly central feed to cause hood forming device.

US-3,439,775 shows such a pivotable film guide. A very important disadvantage of such a film guide is that a few defective wrappings are regularly formed until the correction on the hood forming device has a full effect, since first the film is pivoted further beyond its original path deviation, so that corresponding interruptions in operation and due to the corresponding downtimes result in corresponding additional costs.

The present invention has for its object to improve the film feeders of the type described in the introduction technically and economically considerably, namely u. a. also to the extent that the described default wrappings no longer occur.

This object is solved by claim 1. So far, it has been assumed in the prior art that a forced guidance of such a film, which is unwound from a supply - as stated - irregularly wound up, was not possible because such a film, the thickness of which is generally only a fraction of a millimeter , do not have any compulsory managers exercised. Surprisingly, however, it has been shown that this view is based on an error even if the film fed from the supply roll is not or only slightly tensioned, and that there is no flanging (or even damage) to the longitudinal edges of the film in the case of the positive guidance provided according to the invention.

Preferred embodiments of the present invention are described in subclaims.

Fig. 1

eine seitliche Teilansicht einer stark schematisierten Folien-Zuführeinrichtung für eine angedeutete Haubenbildungseinrichtung in Richtung des Pfeiles I in Fig. 2 gesehen; und

Fig. 2

eine Draufsicht auf die Darstellung gemäß Fig. 1 in Richtung des Pfeiles II in Fig. 1 gesehen.

The invention is explained below using an exemplary embodiment with reference to a schematic drawing. It shows:

Fig. 1

a partial side view of a highly schematic film feed device for an indicated hood formation device seen in the direction of arrow I in Fig. 2; and

Fig. 2

a plan view of the illustration of FIG. 1 seen in the direction of arrow II in FIG. 1.

The drawing shows a highly schematic representation of a (tube) film feed device, designated as a whole, for a hood forming and covering device, which is indicated in FIG. 1 with a dash-two-dot line 2 and for a better overview in FIG 2 is omitted. The hood forming and covering device 2 serves to form and cover a film hood 3 for the purpose of encasing a stack of piece goods 4. This is indicated in FIG. 1 with a dash-dotted line (in the finished covering state).

The film feed device 1 has a film supply of gusseted tube material that is rewound into a supply roll 5. The two end faces of the supply roll are not flat. Rather, the superimposed layers are z. T. in the direction of the central axis 6 of the supply roll 5 outwards or inwards, as is indicated in FIG. 2. The consequence of this is that the film material 5 ', despite the precise central alignment of the supply roll to the standing position of the piece goods stack 4 to be wrapped, wants to dodge to the left or right to the center line 7 when it runs off the supply roll 5.

In order to prevent this, they are subordinate to the supply roll 5 Guide rollers 8 and 9 are provided with stops 10 for the longitudinal edges 11 and 12 of the film material 5 'unwound from the supply roller 5 and thus form a positive guide. The stops 10 are each symmetrical, that is to say set at the same distance from the center line 7 and can be changed in their relative setting to the guide roller 8 or 9 concerned in order to carry out an exact adjustment, but also in the case of piece goods 4 to be encased with a different width B. To be able to feed film material 5 'with a different storage width accordingly. The stops 10 are each formed as rings which are releasably attached to the relevant guide roller 8 or 9 by means of a clamping screw or the like.

As has already been stated, it has surprisingly been found that such a positive guidance of tubular film material is possible without problems, without a film edge 11 or 12 running up at the corresponding stop 10, flanging or even damage. Rather, the stops 10 used for positive guidance, even with a relatively low longitudinal tension of the film material 5, surprisingly exert a highly satisfactory (forced) guiding effect on the film, so that it can be fed to the hood forming and covering device 2 with the simplest of means and perfect loading units 13 are to be formed.

Claims (3)

1. A (tubular) film feeder for a hood forming device, comprising a stock of film reeled to form a supply roll and at least one film guide by means of which the film is guided substantially centrally in relation to the hood forming device, characterised by at least one roller (8, 9) which is rotatable about a fixed shaft and which has lateral stops (10) for positive guidance of the film (5') on its path from the supply roll (5) to the hood forming device (2).
2. A film feeder according to claim 1, characterised in that the stops (10) are adjustable.
3. A film feeder according to claim 1 or 2, characterised in that the stops (10) are constructed in the form of rings which are secured to be releasable relatively to the roller (8, 9).

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