EP1059233A1 - Method and device for packaging objects in a film-hood - Google Patents

Abstract

The stretched opening of the foil wrapper (6) is greater than the outline of the article being packed and before leaving the gripper (8) is guided to increase the draw-off resistance over at least one indentation (15) in the slide face of the gripper so that it is deflected relative to its draw-off direction. Independent claim describes apparatus with gripper movable with lifting frame vertically along object being packed. Slide face of gripper has indentation for deflecting foil against draw-off direction.

Description

The invention relates to a method for packaging objects according to the The preamble of claim 1 and a device for packaging objects according to the preamble of claim 6.

Methods and devices of the generic type are used in particular for Packaging of stacks of goods arranged on pallets is used to pack the goods against slipping on the pallet by those occurring during transport To secure forces and the stack of goods from moisture and other environmental influences to protect. For this purpose, the film hood is pulled in Stretched crosswise and lengthways. That is, it becomes elastic before covering stretched in the transverse direction and elastic in the longitudinal direction during the covering stretched. After covering, the film hood is elastic on all sides resiliently against the stack of goods and the gripped pallet. It takes hold of it Palette. The film hood presses the often consisting of individual bags or boxes Stack of goods in themselves and as a whole against the pallet.

The plastic films used for such packaging are extremely elastic stretchy. However, they also have high internal friction. That is, the Elastic stretched film does not return completely in one after relief "rushing movement" back to their relieved position. Rather, the Return to the relieved state at least partially in a continuous, movement requiring a certain period of time.

EP-A-0 633 186 discloses a method and a device for wrapping of general cargo, in which a stretch film is drawn over a stack of goods becomes. To do this, first a film tube of the desired length is closed welded to a film hood and cut off above the weld. The the film hood formed in this way is made up of four rectangles by means of reefing rollers Gripping devices raised and stretched across in a shape that something is larger than the cross section of the stack of goods to be packed. Then will the film hood by a downward movement of the gripping devices over the Good stack pulled and stretched in the longitudinal direction by the film under Considerable sliding friction is deducted from the gripping devices. To increase the friction of the film when peeling it off, i. H. the vertical stretch To optimize the film, use the reef rollers against the gripping devices pressed. The film pulled off by the gripping devices lays down due to the high internal friction of the film does not immediately stick to the side wall of the load on. Rather, there is such a fixed concern that the film is frictionally attached the cargo only after some time, d. H. some distance from the meantime Gripping devices moved further down. In the lower part of the Stack of goods, d. H. when the bottom edge of the pallet is reached, the foil hood not just let go. Because if you let go, the film that has not yet frictionally engaged the load in the lower area, contract in both the horizontal and vertical directions. The slide end would even before it contracted so far horizontally can reliably reach under the pallet, over the lower edge of the pallet pulled up into the side area of the pallet. To avoid this, the a so-called understretch is actively generated in the lower area of the stack of goods. this happens in that the gripping devices holding the film end compared to the Cover contour (i.e. the contour that the film hood has when covering) be moved inwards, especially under the pallet. By moving inwards of the gripping devices that will still be on the gripping devices tensioned film end relieved. That is, the friction between the gripping devices and the film end that is still clamped on them drops. This increases the risk that the film end before completion of the Unterstretches by the gripping devices slipped. To prevent this, the film hood is used by means of the reef rollers pressed against the gripping devices and thus also with decreasing tension between the film end and the gripping devices securely on the latter held.

In this process, it is true that the foil hood is pressed on by means of the Refroll of the vertical stretch improved. However, an improvement is only up to to some extent possible. Because a too large contact pressure is only about a small area at the corners of the gripping devices can damage the film hood when the film is removed. Under certain circumstances, too much pressure on the reef roller holes, or at least undesired plastically deformed areas in the film hood be generated. Also pressing the film on the grippers to the film has to hold securely on the grippers during the manufacture of the substretches Disadvantage. The reef rollers can not on the (seen in the pulling direction of the film) extreme end of the frame sections immediately below the bottom edge of the pallet come to rest, act. At least not without an additional one construction effort must be accepted. Therefore below the Pallet bottom edge an unnecessarily long and for the actual bottom stretch as such an unnecessary film end section can be provided solely to ensure that the film end also reliably up to the area of the reef rolls protrudes.

DE 90 01 319 U1 describes a further device for packaging objects known to be used in the movable jaws to the film hood to press against the stack of goods in a lower area. This too The procedure prevents the film hood from sliding up until the understretch is completed, however, can easily cause unwanted damage of the film hood or the packaged goods and also brings one unwanted additional construction effort.

It is therefore the object of the present invention, the disadvantages mentioned above to avoid and a method and apparatus for packaging To create objects with a stretch film hood, where possible with The vertical stretch of the film is improved with little structural effort and with a very small excess length of the film compared to the lower edge of the pallet on reliable An understretch of the film hood can be generated.

This object is achieved in an advantageous manner according to the method according to the invention with the characterizing features of claim 1 and according to it Corresponding device with the characterizing features of the claim 6 solved.

The fact that the film over at least one recess of the sliding surface, i.e. least a section in the sliding surface that is opposite to it in the sliding direction immediately preceding and immediately following sliding surfaces the resistance the film offers to its peeling optimized. Because the film pulls in its under tension currently the area bridging the depression together. It penetrates through it into the recess. When leaving the recess, the film is redirected again and stretched again due to the positive connection with the surface deflecting it. An intensified frictional engagement occurs here. It’s not absolutely necessary that the bow-like frame sections in a particular degree compared to the adjacent Project the contour of the frame support.

According to a particularly advantageous embodiment of the method and the Device is provided that the recess over which the film is guided as Gap formed between the bracket-like frame section and the bracket support is. As the bow-like frame section and the bow support usually anyway Two separate components can be represented by enlarging them Simply create a gap in the parting line.

According to a particularly advantageous development of the method and the device it is provided that the gap in before or during the removal of the film its depth T or / and its length L is changed or changed can. Due to the general adjustability, the gap can be adjusted for each individual case relevant parameters such as film material, film thickness, pulling speed, Preloading the film, profile of the stack of goods to be packed, etc. be adjusted. By adjusting the gap during the pulling movement can, it becomes possible, for example, to change in the course of the coating Friction conditions, a charge contour that changes in the pulling direction, but also other parameters that change in the course of the coating To take into account. The fact that the depth T of the gap (i.e. the distance from the lowest point of the gap up to the highest point in the pulling direction of the Foil immediately following sliding surface) and the length L of the gap independently are adjustable from each other, will be a particularly sensitive adjustment to the respective conditions possible.

According to a particularly advantageous development of the method according to the invention the film is guided so that the lower edge of the film hood in the Overdrawn phase snaps into the gap and contracts, so that Film end during the movement of the gripping device in relation to the overlay contour internally to form a substretch, at least temporarily is held. The wrapping of those still in contact with the film The sliding surface is intensified by guiding the film in this way, the friction enlarged.

According to a further embodiment of the method according to the invention the film is passed over the gap so that it is only partially in contact faces the surfaces delimiting the gap. This can cause wrinkles pull apart in the film before the film over the bow-like frame sections running.

According to a further embodiment of the device according to the invention the at least one depression of the sliding surface is as close as possible to the end of the Arranged gripping device on which the film runs from the gripping device. This means that a very short section of film is sufficient to place the film on the gripping devices to hold while opposing this to forming a substretch the overlay contour can be moved inwards. Foil is saved.

According to a further embodiment of the device according to the invention the sliding surface, seen in the sliding direction of the film, almost jumps into the recess. This is especially for holding the film important snapping of the film end in the manufacture of the Unterstretches the recess favors the end of the film when it reaches the recess is suddenly relieved.

Preferably, the inventive device is designed so that the Gap on each gripping device extends over its entire outer circumference. This means that the entire circumference occurs when the film is pulled off in the pull-over phase the bow-like frame section has increased resistance, which is the vertical stretch improved. In addition, this design can keep the film in the Improve the phase of making the bottom stretch.

Further advantages result from the remaining subclaims and are pending Hand of the embodiments recognizable.

Fig. 1

eine perspektivische Ansicht der wesentlichen Teile einer Vorrichtung zum Verpacken von Gegenständen gemäß einem Ausführungsbeispiel der vorliegenden Erfindung;

Fig. 2

eine Greifeinrichtung beim Überziehen der Folienhaube über den Gegenstand;

Fig. 3

eine Greifeinrichtung nach dem Überziehen der Folienhaube, vor Herstellung des Unterschrumpfes;

Fig. 4

eine Greifeinrichtung nach Herstellung des Unterschrumpfes;

Fig. 5

eine vergrößerte Detailansicht einer Greifeinrichtung während der Überziehphase;

Fig. 6

eine vergrößerte Detailansicht einer Greifeinrichtung während der Überziehphase, bei Auftreten eines Faltenwurfes;

Fig. 7

eine vergrößerte Detailansicht einer Greifeinrichtung in der Überziehendphase;

Fig. 8

eine weitere vergrößerte Detailansicht einer Greifeinrichtung in der Überziehendphase, und

Fig. 10

eine Aufsicht auf einen bühelförmigen Halteabschnitt

The invention is explained in more detail below on the basis of a preferred exemplary embodiment with reference to the accompanying drawings. Show it:

Fig. 1

a perspective view of the essential parts of an apparatus for packaging objects according to an embodiment of the present invention;

Fig. 2

a gripping device when pulling the film hood over the object;

Fig. 3

a gripping device after covering the film hood, before producing the shrink fit;

Fig. 4

a gripping device after the manufacture of the lower shrinkage;

Fig. 5

an enlarged detail view of a gripping device during the pulling phase;

Fig. 6

an enlarged detail view of a gripping device during the pulling phase, when a fold appears;

Fig. 7

an enlarged detail view of a gripping device in the stalling phase;

Fig. 8

a further enlarged detailed view of a gripping device in the stalling phase, and

Fig. 10

a top view of a bracket-shaped holding section

The device for packaging objects 1 shown in FIG. 1 has one Supply roll, not shown, for a folded film tube 3, of unwound the supply roll and fed to a central packaging unit becomes. The packaging unit has a frame in which to be packed Objects are transported, and a packaging facility guided on this frame on. From this packaging facility are for the better Illustration only shows the components relevant to the invention.

As can be seen in FIG. 1, the film tube 3 is connected via a deflecting rod 4 led vertically down to a welding and cutting device 5. Below the welding and cutting device 5, the film tube 3 is opened and gripped from the inside by four movable gripping devices 8. The gripping devices 8 consist of the bracket-like frame sections 8 a and the bracket supports 8 b. The bracket-like frame sections 8 a and the bracket supports are L-shaped or C-shaped and thus define the corners of the film hood.

Following the gripping of the film tube 3 is a predetermined length of the film tube 3 on the gripping devices. This is done by a reefing roller 10 on each outside of each gripping device 8, the film tube 3 pulls on the gripping device, which causes the film tube on the discharge side the reef roll merges into a folded supply 6 a. (Hitting the slide not shown in the drawing using the reef rollers). The film tube 3 is then welded and cut to a desired length so that a Foil hood 6 is formed, which by the four gripping devices 8 into a rectangle is spanned. The film hood 6 stretched in this way is in a next one Step stretched in the horizontal direction so that the lower opening of the film hood 6 is somewhat larger than the cross section of the stack of goods 1 to be packed. In this state, the film takes on its "covering contour". Then will the film hood 6 is moved down and pulled onto the stack of goods 1. The the welded end of the film hood lies on the top of the stack of goods 1 on. The film is now, braked by the gripping devices 8, pulled off. Here it is stretched in the vertical direction.

This phase of covering with vertical stretching is shown in FIGS. 2 and 3 Associated detail enlargement Fig. 5. The film hood 6 is in when pulling in deducted in the vertical direction continuously from the dormant stock 6 a. It passes the freely rotating roller 9, which acts as a counter roller when the film hits it serves for the reef roller 10. From the main sliding surface 8 a of the bow-like Frame section 8 is the film over the gap representing a recess 15 pulled.

A different design of the depression (not shown here), for example as a local trough that is rounded on all sides is possible. At only local extension of the depression, it is particularly advantageous if the depression extends over the outer corner, i.e. the intersection of the two legs the gripping device extends.

Since the film in the area of the gap 15 no longer has bow-like frame sections is supported, it pulls due to its bias during the Passage across the gap together, d. H. it pulls into the gap. Because of that the film, due to its internal friction, does not is suddenly able to contract completely, it depends on the dimensions L and T of the gap (dimensions: see Fig. 9), with what intensity the film in the Gap.

The wrapping of the bow-like frame section 8 is increased by the penetration of the film into the gap 15. The film lies to an increased extent on the area 8 e of the bow-like frame section 8 a facing away from the sliding side of the film. The film lying against the bow-like frame section in this area can only be pulled off the bow-like frame section 8 a by being further expanded, viewed in the circumferential direction. This leads to a significant increase in the frictional forces effective when pulling off. Because now the film is no longer pulled essentially only by the horizontal forces of the film indicated as F _H on the film cutting line (resulting from the film tension in the horizontal direction) against the bow-like frame section 8 a. The vertical film forces, indicated as F _V on the vertical cut line of the film, now also make a significant contribution to pulling the film against the region of the bow-like frame section 8 a facing away from the slide side of the film. There is a self-reinforcing effect. The forces that tend to pull the film from the bow-like frame section 8 a, at the same time increase the frictional forces counteracting pulling off.

The vertical stretch, i. H. the one that occurs when you pull it off Sliding friction force, influenced in a wide range by the fact that the length, on which the film 6 wraps around the bow-like frame section 8 a, by a Variation of the gap dimensions L and / or T (Fig. 9) to the given requirements is adjusted.

Fig. 6 shows the situation when a fold 6 e from when pulling the hood withdrawn stock 6 a is withdrawn. The fold slides the sliding surface 8 c of the Bow support 8 b along. The foil sections are folded through the strong horizontal bias of the film is pressed tightly together. Between static friction occurs in the folds of film. If under unfavorable circumstances this static friction is greater than the sliding friction between the film and the sliding surface of the gripping device, the fold can no longer pull apart as long as they are under tension over the gripping device slides. This is undesirable. Because especially if there is a crease in the area of the bow-like frame sections, the film becomes impermissible loads exposed.

The gap 15 prevents this. As soon as the fold 6 e in the area of the gap 15 glides, the fold is temporarily relieved of horizontal forces. The wrinkled one on top of the other placed film sections are no longer pressed against each other. The The fold can open and the film can align itself.

Fig. 7 shows the situation immediately upon completion of the covering of the hood. The vertical movement of the gripping device 8 has ended. The slide is complete from the sliding surface 8 c of the stirrup support 8 d has been deducted. The slide end is just slid into the gap 15.

FIG. 7 represents a snapshot insofar as it shows an outer end 6 b of the film hood that currently projects freely into the gap. However, this end, in particular depending on the internal friction of the film, is immediately caused by the film forces F _{R (} resulting from the film horizontal forces F _H and the film vertical forces F _V , see FIG. 5) on the cut surface of the film Because of the gap 15 or, preferably, applied to the area of the bow-like frame section 8 a facing away from the sliding side of the film.

The situation shown in FIG. 8 thus occurs. The bow-like frame section 8 a engages behind the film opening. At each of the four lower corner points of the film hood a kind of "bag" is pulled into the film. This "bag" loops around the bow-like frame section 8 a. The wrap angle W (i.e. the angle at which the film faces the area facing away from the slide side of the film of the bow-like frame section 8a wrapped around the horizontal) is advantageously greater than 30 degrees. The opening 6 d of the film hood has a smaller extent than the areas of the Foil hood, as these are stretched by the bow-like frame section 8 a.

This means that the film hood can be used for the manufacture of the substretches the static friction between the film and bracket-like frame section 8 a held securely become. To slide off the film hood from the holding portions 8 b leave, the film hood in the region of its opening 6 d should continue in the circumferential direction be stretched. However, the forces required for this are due the extensive wrap of the holding portion 8 b and accordingly high frictional forces are no longer available. The related self-reinforcing effect described with FIGS. 2 and 5 now comes here good for stiction. With suitable dimensioning of the gap, self-locking occurs on. That is, the forces that tend to pull the foil off the bow-like Subtract frame sections 8 a, always pull the film in such at the same time Dimensions of the areas of the bow-like areas facing away from the sliding side of the film Frame sections 8 a that the static friction is insurmountably increased.

Additional holding measures, such as pressing the film, etc., are possible in principle not necessary.

When dimensioning the gap and the length of the during manufacture of the Unterstretches in the gap protruding film end, if necessary the following effect can be used. As long as the film is in the covering phase of the hood bridging the gap, it pulls with appropriate dimensioning of the The gap is not completely in the gap. This can cause the film the bow-like frame section 8 a wraps only to such an extent that the sliding friction is increased, but there is no self-locking. The slide end in contrast, can penetrate deeper into the gap and thus settles in to a greater extent on the bow-like frame section 8 a. So that the friction be increased further in the overdraft phase. Under certain circumstances the self-locking phase of the film can be achieved.

Fig. 4 shows the situation when the Unterstretches is completed. The foil has frictionally applied to the side edge of the pallet. The tension of the film in the vertical direction, this has almost broken down. The bow-like frame section 8 a can therefore easily by moving the gripping devices further inwards 8 be released from engagement with the film.

Fig. 9 shows a bow-like frame section 8, in which an alternative design of the gap is executed. The rounding in the bottom of the gap can advantageously partially support the film when crossing the gap. Farther the rounding can be beneficial when holding the film shown in FIG. 8 impact by the end of the film also in this phase up to runs into the area of the curve.

The dimension L shown in FIG. 9 can be changed in a simple manner by the bracket-like frame section attached to the guide rods 13 and 14 8 a in the vertical direction more or less pulled out of the bracket supports 8 d becomes. If the rods 13 and 14 in the corresponding guides run, all that needs to be done is the clamping (not shown in FIG. 9) between the Rods 13 and 14 and their guides are lifted. If necessary, it can Dimension L can also be changed during stalling if possible is provided to move the rods 13 and 14 motor-driven.

There are various different ways of setting the dimension T shown in FIG. 9 Possibilities. The possibility of eccentric rod 14 is given purely by way of example to store rotatable. Such storage would also be one Allow easy motor adjustment of size T. Otherwise, however can also be used, for example, with (possibly profiled) sleeves in the area of the gap 15 can be slipped over the rod 14 or over the rods 13 and 14.

Fig. 10 shows a view of a bracket-like frame section 8 a, of seen above. The rods 13 a and 14 a are indicated in dashed lines Gap 15 profiled and thus make it possible to find the one located in the area of the gap 15 To guide or support the film locally. These rods match of the rod 14 shown in Fig. 9. The rods 13b and 14b provide an alternative Execution. They are circular cylindrical throughout and offer none specially defined support or guidance.

Reference list

1

Palletized stack of goods

2nd

palette

3rd

Foil tube (when folded, deducted from stock)

4th

Deflection rod or pulley

5

Welding and cutting device

6

Foil hood

6a

dormant foil hood

6b

outermost corner of the film hood

6c

Outer edge of the film hood

6d

Opening of the film end, i.e. Hood opening

6e

Drapery in the film

7

Head weld of the foil hood

8th

Gripping device

8a

bow-like frame section

8b

Stirrup support

8c

Sliding surface of the bow-like frame section

8d

Sliding surface of the stirrup support

9

Counter role to the reef role

10th

Reef role

11

poor

12th

guide

13

Vertical guidance of the holding section

14

Vertical guidance of the holding section

15

Constriction or gap

Claims (17)

Method for packaging objects, in particular a palletized stack of goods (1) with a tubular or hood-shaped stretch film, which is thrown onto several gripping devices (8) with bow-like frame sections (8a) and frame supports (8b) of a lifting frame that can be moved in the vertical direction and by means of the Gripping devices is stretched such that the open opening of the film hood (6) is larger than the outline of the object to be packaged, and wherein the film hood (6) is pulled over the object with a certain stretch transversely to the plane of the open opening of the film hood, characterized in that the film is guided over at least one recess (15) in the sliding surface of the gripping device so that it is deflected relative to its pulling direction before the draining from the respective gripping device (8) to increase the pull-off resistance. Method according to claim 1, characterized in that the film (6) is guided over a gap (15) arranged between the bow-like frame section (8a) and the frame support (8b). Method according to claim 1 or 2, characterized in that the gap (15) is changed in depth (T) and / or length (L) before or during the removal of the film. Method according to one of the preceding claims, characterized in that the film (6) is guided in such a way that the lower edge of the film hood snaps into the gap (15) and contracts in the pull-over phase, so that the film end during the movement of the gripping device ( 8) is at least temporarily held in relation to the overlay contour on the inside to form an understretch. Method according to one of the preceding claims, characterized in that the film (6) is guided over the gap (15) in such a way that it is only partially in contact with the surfaces delimiting the gap. Device for packaging objects, in particular a palletized stack of goods (1) with a tubular or hood-shaped stretch film (6) and a bracket-like frame sections (8a) with bracket supports (8b), arranged on a lifting frame and having rounded film contact surfaces, with bracket supports (8b) Reefing rollers (10) which can be brought into contact with the gripping device (8) for contacting and stretching the film hood (6), the gripping device with the lifting frame being movable in the vertical direction along the object to be packed, characterized in that in the sliding surface of the gripping device (8 ) at least one recess (15) is provided, through which the film can be deflected relative to its pulling direction to increase the pulling resistance. Apparatus according to claim 6, characterized in that the at least one depression (15) of the sliding surface is arranged as close as possible to the end of the gripping device (8) at which the film runs off the gripping device. Device according to claim 6 or 7, characterized in that at least one depression (15) of the sliding surface is arranged in the bow-like frame section (8a) and / or the bow support (8b). Device according to one of the preceding claims, characterized in that the sliding surface, viewed in the sliding direction of the film (6), merges into the recess (15) approximately in a sudden manner. Device according to one of the preceding claims, characterized in that the length (L) of the recess (15) in the pull-off direction is at least 10 mm. Device according to claim 6, characterized in that the depression (15) of the sliding surface is formed by a gap. Apparatus according to claim 11, characterized in that the gap (15) is arranged between the bracket-like frame section (8a) and the bracket support (8b). Device according to one of the preceding claims, characterized in that the depth (T) and / or its length (L) can be varied in the gap (15). Device according to one of the preceding claims, characterized in that the depth (T) or / and its length (L) of the gap (15) can be changed while the film (6) is being pulled off. Device according to one of the preceding claims, characterized in that the gap (15) on each bow-like frame section (8a) extends over its entire outer circumference. Device according to one of the preceding claims, characterized in that in particular the bracket-like frame sections (8a) are provided with a friction- increasing coating or are made of a material which has a particularly high coefficient of friction in contact with film plastics. Device according to one of the preceding claims, characterized in that the gap (15) has guiding surfaces for the film (6) at least locally along its course in the pulling direction.

Images