EP0460681B1 - Device for folding in a concertina-fashion and/or stretching a tubular stretchable packaging film - Google Patents

Description

The invention relates to a device for reefing and / or stretching tubular or hood-shaped stretch film when wrapping piece goods, in particular cuboid or cube-shaped stacked piece parts, such as, for example, and in particular multi-layer, palletized piece goods stack, by means of stretch film, with one of several essentially existing (reef) frame arranged in a plane, bow-shaped frame sections, over which the supplied, spread (tubular) stretch film is to be drawn before the piece goods are wrapped, the clear frame contour being larger is (or has to be made larger) than the outer contour of the piece goods to be wrapped, the frame sections have an essentially continuous, preferably rounded or curved shape, at least in the area of their outside that comes into engagement with the stretch film, and the frame sections each have a Frame section support are held.

A device for wrapping piece goods with a stretch film hood is known from DE-GM 88 08 508. In this case, the tubular stretch film is partially pulled off a film supply by a pull-off device and separated from the film supply by means of a cutting device, the pull-off device being provided with a spreading device for pulling apart and later spreading apart the film section which later forms a hood, and a reefing device downstream of the spreading device for reefing the Film section over a vertical distance which is less than the length of the film section, in addition a welding device arranged between the spreading device and the reefing device for forming a seam, and finally a stretching device by means of which the film section is to be stretched, and a lifting device by means of which the formed hood is finally to be pulled over the piece goods to be wrapped underneath.

In this known device, the reefing and stretching device has a so-called reefing frame, which consists of four bow-shaped frame sections ("reefing bars") arranged in a horizontal plane, each of which has the shape of an isosceles L in plan view, the apex area being rounded off. The tubular or dome-shaped stretch film is guided over these bow-shaped frame sections before the piece goods are wrapped and applied to the frame section supports ("reef spars") in the reefed state (that is to say in the form of folds) before the stretching is then carried out by moving the bow-shaped frame sections apart, and the stretched film hood is then pulled over the piece goods to be wrapped, whereby they are pulled together for the purpose of creation a transport lock and a weather-resistant loading unit should be placed intimately on the piece goods.

If the coefficient of friction between the film material and the surface of the bow-shaped frame sections engaging with it is relatively high, the film may only be pulled over the bow-shaped frame sections at a relatively low speed in order to avoid overstretching. If, however, there is a very low coefficient of friction, at least a relatively high lowering speed must be used if, in addition to the horizontal stretch already indicated above, it is also advantageous to obtain a considerable vertical stretch of the film material.

For the latter in particular, a certain undercut is provided between the bow-shaped frame sections and the supports holding them in the known device or its reefing and / or stretching device. However, it has been shown that, on the other hand, this must not be too large in order to ensure that the film slides properly from the bow-shaped frame sections.

In addition, it has been shown in the extensive (further) development work that the design of the bow-shaped frame sections and in particular also their supports are of considerable importance for proper operation comes to.

The present invention has for its object to improve the known reefing and / or stretching devices in particular to the effect that not only a proper clamping and ref fen of the tubular film material, but in particular also an optimal, perfect sliding off the device (to the piece goods to be wrapped ) is possible.

According to the invention, this object is achieved in that the frame section supports are each formed with a flat (ie no longer essentially linear) outside, which faces away from the (bottom) side of the frame section in question in the film feed direction (facing away from the film feed direction ( downwards), and which - essentially following the shape of the relevant frame section in a projection plane running transversely to the film feed direction - extends at least at the upper end section essentially over the length of the relevant frame section.

In a preferred embodiment, the frame supports can be plate-shaped (and, of course, curved at least in the "corner area") and can consist, for example, of sheet metal, but they can also be made, for example, of appropriately designed plastic blocks or the like. Another variant that makes use of the inventive concept consists, for example, in that the frame section supports each consist of essentially parallel rods or the like. exist, the outer envelope forms a flat outside, so that the effect sought according to the invention can be achieved at least substantially.

According to a most preferred embodiment, the outer side of the frame section supports facing the film material each be conically tapered from the relevant frame section, in which case the free edge of a frame section support removed from the frame section lies (still) outside the contour of the piece goods to be wrapped or is to be brought into such a position.

The frame sections preferably each project laterally over their support, so that the latter is, as it were, undercut, the protrusion of the outer contour of the frame sections above their associated support preferably decreasing towards the end sections of the relevant frame section.

For a cube-shaped or cuboid-shaped piece goods stack, the frame sections are each arranged in a corner area, whereby they can preferably be formed in a circular arc shape in their central area over an angle of approximately 90 ° and, in a further embodiment, can be formed on the essentially circular arc shape Section can connect a section at both ends, which has a small curvature or is angled inwards.

The frame section supports (as seen in plan view) are preferably formed in each of their two end regions essentially tangentially to the curvature of the films stretched between them, so that an optimal transition is ensured.

In a further embodiment of the present invention, the central region of the frame section supports can be excluded in each case, the mutually facing edge sections on the recessed part of a frame section support then preferably being rounded or curved inward in order to ensure unimpeded entry and exit .

At least one reefing roller can be assigned to each or each frame section, wherein the reefing rollers can each be movable towards or away from the frame section assigned to them. It has been found that the reefing rollers should preferably be arranged in each case on the upper region of a frame section support in order not to hinder the actual reefing process in any way.

For the horizontal stretching process, the frame sections are to be moved apart in such a way that their mutual distance increases.

In addition, it is not mandatory that the frame sections are essentially only available in the corner areas. Rather, at least two (possibly also all) frame sections adjacent to one another can be connected to one another, and in such an embodiment preferably telescopically, in order to nevertheless be able to move apart expediently.

Preferred embodiments of the present invention are described in the subclaims.

Fig. 1

eine etwas vereinfachte räumliche Darstellung eines mit einer Stretchfolienhaube zu umhüllenden Stückgutstapels;

Fig. 2

eine Darstellung gemäß Fig. 1 nach dem Abschweißen des Folienschlauches und Abtrennen der Folienhaube;

Fig. 3

eine Darstellung gemäß den Fig. 1 und 2, in welcher die Folienhaube bereits quergestretcht ist;

Fig. 4

eine Darstellung gemäß den Fig. 1 bis 3 während des Überziehvorgangs;

Fig. 5

eine Teildraufsicht auf die Reff- und Spreizeinrichtung in einer gegenüber den Fig. 1 bis 4 vergrößerten Darstellung;

Fig. 6

eine (gegenüber Fig. 5 vergrößerte) Draufsicht auf einen Rahmenabschnitt und dessen Stütze in Richtung der Pfeile VI in Fig. 5 gesehen;

Fig. 7

eine Fig. 5 entsprechende, gegenüber Fig. 5 verkleinerte Darstellung eines bügelförmigen Rabmenabschnittes in der Draufsicht;

Fig. 8

eine Seitenansicht auf die Rahmenabschnitt-Stütze des bügelförmigen Rahmenabschnittes gemäß Fig. 7 in Richtung des Pfeiles VIII in Fig. 7 gesehen; und

Fig. 9

einen Querschnitt durch einen bügelförmigen Rahmenabschnitt und den oberen Teil seiner Stütze mit aufgereffter Folie.

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

Fig. 1

a somewhat simplified spatial representation of a piece of goods to be wrapped with a stretch film hood;

Fig. 2

a representation of FIG. 1 after welding the film tube and severing the foil hood;

Fig. 3

a representation of Figures 1 and 2, in which the film hood is already stretched;

Fig. 4

a representation of Figures 1 to 3 during the pulling process.

Fig. 5

a partial plan view of the reefing and spreading device in an enlarged view compared to Figures 1 to 4.

Fig. 6

a (enlarged with respect to FIG. 5) top view of a frame section and its support seen in the direction of arrows VI in FIG. 5;

Fig. 7

a representation corresponding to FIG. 5, reduced compared to FIG. 5, of a bow-shaped rabmen section in plan view;

Fig. 8

a side view of the frame section support of the bow-shaped frame section according to FIG 7 seen in the direction of arrow VIII in Fig. 7. and

Fig. 9

a cross-section through a bow-shaped frame section and the upper part of its support with ruffled film.

1 to 4 show a stacked, multi-layer, cuboid piece goods stack 1 by means of a palletizing device, which is to be wrapped with a film hood 2 consisting of stretch film (stretch film) tubular stretch film material 3 is formed, which is supplied from a tubular film supply, not shown.

1 shows the state in which the lower end section of the supplied tubular stretch film material 3 has already been excluded from the reefing and stretching device, which cannot be seen in detail and is described below.

Fig. 2 shows the state in which the supplied tubular stretch film material 3 has already been separated from the formed film hood 2, which for this purpose has received a transverse seam 5 at its upper end by means of a welding device 4. In addition, it can be seen in Fig. 2 that the film hood 2 has already been essentially thrown onto the reefing and stretching device.

From FIG. 3 it can be seen how the hood 2 which has been fitted onto the reefing and stretching device has been stretched horizontally in the direction of the arrows 6 by moving apart its frame sections, which are described in more detail below, in order to be able to be pulled over the packaged goods stack 1; and FIG. 4 shows an intermediate step in wrapping the piece goods stack 1, in which the upper end section of the piece goods stack 1 is already covered by the film material of the film hood 2, while the lower end section of the piece goods stack is still free, but when the reefing and stretching device is further lowered in Direction of arrows 7 will still be wrapped.

The reefing and stretching device already mentioned repeatedly has a reefing frame which essentially consists of four bow-shaped frame sections 8 arranged in a (horizontal) plane (of which only visible in FIG. 5) two frame sections 8 are shown), and which are each arranged in a corner area at a distance from the piece goods to be wrapped, which is indicated in FIG. 5 with a dash-two-dot line.

The frame sections 8 each consist of round material and are each formed in a circular arc shape in their central area in the top view over an angle α of 90 °. At both ends of the middle circular section there is a section 10 which has a smaller curvature or is angled inwards, so that the ends 11 of the bow-shaped frame sections 8 or their end sections 10 are free of the film material of the hood 2 and for the latter there is an optimal transition into the "free path" to the neighboring frame section 8.

As can already be seen from the top view according to FIG. 5 and otherwise from FIGS. 6 to 9, the frame sections 8 each project laterally beyond their frame section support 12, so that the latter is, as it were, undercut. This protrusion a decreases at / towards the end sections 10, as can be seen from the lower part of FIG. 5.

The frame section supports 12 are each formed with a flat outer side 13 and extend downward from the underside 15 (see FIG. 6) of the relevant frame section 8 facing away from the film feed direction 14 (see FIG. 1) in the film feed direction 14 , namely in a (horizontal) projection plane running transversely to the film feed direction 14, essentially following the shape of the relevant frame section 8, at least in the area from the end sections into a central area. The frame section supports 12, referred to above and below as "supports", are in the illustrated embodiment plate-shaped and made of sheet metal. You could, however, or the like in a variant, for example, also from a plurality of parallel rods. exist, whose outer envelope forms a flat outside in the sense of the present invention.

As can be seen in particular from FIG. 6, in the exemplary embodiment shown, the supports 12 made of sheet metal each taper downwards from the associated frame section 8, the central region 12 ′ of the supports 12 being excluded in each case and the facing edge sections 16, 16 are rounded off on the recessed part 12 '.

The surfaces of the frame sections 8 and the supports 12 which come into engagement with the film 2 are polished in order to enable good sliding.

As can be seen in particular from FIG. 5, the supports 12 (viewed in plan view) each run at their two end regions 17 essentially tangentially to the curvature of the film 2 to be clamped between them, so that there is an excellent transition.

The frame sections 8 are each assigned a reefing roller, not shown in detail in the drawing, which can be swiveled (and accordingly also swung away again) to the frame portion 8 assigned to it, specifically the reefing rollers are each arranged in the upper region of a support 12, around which Do not hinder reefing in any way.

The frame sections 8 are to be moved apart according to FIG. 3, increasing their mutual distance, in order to close the film hood 2 in the form already described stretch.

In the process as described above with reference to FIGS. 1 to 4, the lower end section of the tubular stretch film material 3 is therefore first pulled over the four bow-shaped frame sections 8 and is detected by the reefing rollers, which are not shown in detail in the drawing, which the film material 3 in the manner shown in Fig. 2 reef over the bow-shaped frame sections 8 on the frame section supports 12. The (elastic) film can be seen due to the formation of the frame sections 8 - especially at the transition sections - not overstretched. Rather, due to the highly expedient configuration of the bow-shaped frame sections 8 according to the invention (in the plan view, see FIG. 5), an extremely smooth transition to the “free areas” takes place.

Likewise, there is a highly expedient transition from the bow-shaped frame sections 8 to the frame section supports 12, as can be seen in particular from FIG. 9, where the reefed film is indicated and designated 3 '.

The same then also applies evidently when stretching horizontally according to FIG. 3 and not least when pulling on the stretch film hood according to FIG. 4. Until the soft, intimate application to the piece goods stack 1, the film hood 2 can be held with the reefing rollers, if necessary, in order to spring back vertically Prevent security.

Overall, the reefing and spreading device according to the invention is an embodiment which, at relatively high working speeds and corresponding throughput capacity, leads to an optimal wrapping of piece goods with a tubular shape or hood-shaped stretch film and leaves nothing to be desired, neither in technical nor in economic terms.

Claims (20)

1. Apparatus for reefing and/or stretching stretch film of tubular or hood shape, in the wrapping of piece goods, more particularly piece goods stacked in the form of blocks or cubes, such as, for example, and, more particularly, multi-layer palleted piece goods stacks, by means of stretch film, comprising a (reefing) frame consisting of a plurality of bow-shaped portions disposed substantially in one plane, over which frame the supplied and spread-open stretch film is drawn before the piece goods are wrapped, the inside frame contour being larger, or made larger, than the outside contour of the piece goods for wrapping, the frame portions, at least in the zone of their outside coming into engagement with the stretch film, having a substantially continuous and preferably rounded or curved shape and the frame portions each being held by a frame portion support, characterised in that the frame portion supports (12) are each constructed with a flat outside which extends in the film feed direction (14) from that side (15) of the associated frame portion (8) which is remote from the sheet feed direction (14) and in a projection plane extending transversely thereto extends, substantially following the shape of the associated frame portion (8), substantially along the same at least at the top end portion.
2. Apparatus according to claim 1, characterised in that the frame portion supports (12) are in the form of plates.
3. Apparatus according to claim 2, characterised in that the frame portion supports (12) consist of sheet metal or the like.
4. Apparatus according to claim 1, characterised in that the frame portion supports (12) consist of substantially parallel bars or the like, the outer envelope curve of which forms a flat outside.
5. Apparatus according to any one or more of the preceding claims, characterised in that the outside of the frame portion supports (12) facing the film material is in each case constructed to taper conically from the associated frame portion (8).
6. Apparatus according to any one or more of the preceding claims, characterised in that the frame portions (8) each project laterally beyond their support (12).
7. Apparatus according to claim 6, characterised in that the projection (a) of the outer contour of the frame portions (8) beyond the associated frame portion support (12) decreases towards the end portions (10) of the frame portion (8).
8. Apparatus according to any one or more of the preceding claims, characterized in that the frame portions (8) and/or the surfaces of the frame portion supports (12) coming into engagement with the film are polished or the like.
9. Apparatus according to any one or more of the preceding claims for wrapping piece goods in the form of a cube or block, characterised in that the frame portions (8) are each disposed in a corner zone of the corresponding piece goods contour in manner known per se.
10. Apparatus according to any one or more of the preceding claims, more particularly according to claim 9, characterised in that the frame portions (8) are each constructed (in plan view) in the form of an arc of a circle over an angle (α) of about 90° in their middle zone.
11. Apparatus according to claim 10, characterised in that adjoining each end of the substantially arcuate portion is a portion (10) which has a smaller curvature or is bent inwards.
12. Apparatus according to any one or more of the preceding claims, more particularly according to claim 11, characterised in that the frame portion supports (12) (as considered in plan view) each extend, at their two end zones (17), substantially tangentially to the curvature of the film to be clamped between them.
13. Apparatus according to any one or more of the preceding claims, more particularly one or more of claims 9 to 12, characterised in that the middle zone (12') of the frame portion supports (12) is in each case recessed.
14. Apparatus according to claim 13, characterised in that the facing edge portions (16, 16) of the recessed part (12') of a frame portion support (12) are rounded.
15. Apparatus according to any one or more of the preceding claims, characterised in that at least one reefing roller is associated with one or each frame portion (8).
16. Apparatus according to claim 15, characterised in that the reefing rollers are each movable towards and away from their associated frame portion (8).
17. Apparatus according to claim 15 or 16, characterised in that the reefing rollers are each disposed in the top zone of a frame portion support (12).
18. Apparatus according to any one or more of the preceding claims, characterised in that the frame portions (8) can be moved apart in manner known per se to increase the distance between them for horizontal stretching of the film hood (2).
19. Apparatus according to one or more of the preceding claims, characterised in that at least two adjacent frame portions (8, 8) are telescopically interconnected.
20. Apparatus according to claim 19, characterised in that all the frame portions (8) are each telescopically connected to their neighbouring frame portions (8, 8).

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