EP1184281B1 - Method an apparatus for packaging objects - Google Patents

Abstract

The method for fitting stretch film over palletised goods (1) comprises forming a hood (6) from the film with concertina folds in its lower edge, using vertically adjustable grippers on a frame. These are then moved sideways to apply tension to the film and open the base of the hood so that it fits over the goods and the film is stretched. The frame is then lowered over the goods so that the film is released from the grippers and stretched vertically. The novelty is that the tension of the film over the top of the goods is controlled. An Independent claim is included for a machine for carrying out the process.

Description

The invention relates to a method for packaging articles with a tubular, in particular as gusseted tube web-guided stretch film after the The preamble of claim 1 and a device for packaging objects according to the preamble of claim 8. Such devices and methods are particularly used to pack pallets stacked on pallets to the stack in the case of using a film hood during transport protection against moisture and other environmental influences. In addition, the wrapping of the good pile confers with a foil hood or a banderole of the packaging unit increased Stability, as the film hood or band when coating over the stack in horizontal and vertical direction is stretched and after coating under tension rests against the stack and the pallet.

From DE 39 21 190 C2 is such a method and apparatus for packaging objects in one tubular plastic film, in which a film hood on gripping devices, which are arranged on a vertically movable frame, is auffffffft. Subsequently the gripping devices are moved apart in the horizontal direction, whereby the Film hood is stretched in the horizontal direction. On the frame are against the Gripping devices engageable and driven waves provided, and on each gripping device is arranged an endless circulating band, which is connected to the outer surface of the Wave is in contact. By the rotation of the shaft in one direction, the film be pushed onto the gripping device. During the subsequent coating of the film hood over the stack, the film hood can then by the rotation of the shaft in the opposite direction can be deducted from the frame in a controlled manner.

Although this device allows control of the vertical stretch of the film, however proves to be disadvantageous in this device that the horizontal stretch of the film the top of the items to be packaged is not satisfactory. Consequently, a Overstretching of the film hood arise when the gripping devices after pushing Move apart of the film and stretches the film hood horizontally. It comes thus at those points of the film hood, where the grippers engage in the hood and these stretch, to thin areas, so vulnerable areas especially at the corners of the packed good pile. This problem can be avoided in a known manner Be by the gripper bar a considerable length and a wide contact surface for the Have film, so that distribute the expansion forces accordingly. However, this solution has the disadvantage that the gripper for gripping the film is not on a small cross-section can move together. The collision on the smallest possible cross section However, it is desirable and possible for reasons of space, because today's films themselves allow high strains at low outlet cross-sections of the hose.

From DE 43 07 287 C is a similar method for wrapping a stack of goods with about its height different base areas with a foil hood known, in which the film hood is aufgerefft on reefing equipment. This method is intended that depending on the vertical position of the Reffeinrichtung in areas of the stack of goods Tension of the film hood in the vertical direction stretched or relaxed by the Reffeinrichtung becomes. As a result, the vertical stretching of the film hood by the Reffeinrichtung in these areas of the pile of goods with over its height different base areas controlled.

The same problems arise in an open-top hose stretch, a so-called Banderole cut to a suitable length.

The object of the invention is to provide a method and a device for packaging To create objects that the overstretching of the film hood or band and In particular, the formation of thinned film areas in the top of the avoid to be packed.

This object is achieved by the method according to claim 1 and by the device solved according to claim 8. Advantageous embodiments of the invention are in the Subclaims defined.

In the inventive method for packaging objects, the formed Film hood or the band on several, in a substantially horizontal direction movable gripping means of a movable in a substantially vertical direction Lifting frame aufrifffft. Subsequently, the deferred foil hood or banderole by the movement of the gripping means in the substantially horizontal direction clamped so that the clamped opening of the film hood or band larger than the plan view of the article to be packaged and wherein the film hood or band is stretched in a substantially horizontal direction. In a next step the film hood or banderole by the substantially vertical movement of the Lifting frame pulled over the object, the film hood or band there is withdrawn from the gripping means and in a substantially vertical direction is stretched. The inventive method is characterized in that the voltage the film hood or band is controlled at the top of the stack. hereby can the horizontal stretch of the film at the top of the good on the respective practical circumstances, in particular to the outline of the pile of goods, causing overstretching and formation of thinned areas in the film be avoided and at the same time a good investment of the stretched film in particular in upper range of the packaged goods is achieved.

In an advantageous embodiment of the method is during the stretching of the Film hood or banderole the film partially withdrawn from the gripping device. This will allow part of the film to be stretched horizontally is released again. As a result, overstretching with thin areas in some areas avoided in the film, which occur in particular at the locations of the film on which the gripping devices are located.

In an advantageous embodiment of the invention, the removal speed of the film during the tightening of the film hood or banderole by controlled unrolling the film of the gripping means less than the speed of horizontal movement the gripping devices. This ensures that the foil hood or band However, while stretching is still stretched during stretching, the degree of stretching is in the corner areas, in which the film is pulled over the bow-shaped gripper is reduced, compared to conventional devices, so that an overstretch in horizontal direction is avoided.

To during the coating of the film hood or banderole on the palletized object Achieving a good stretch in the vertical direction is another preferred one Embodiment The removal speed of the film during the coating less than the vertical speed of the lifting frame.

In a particularly preferred embodiment of the method according to the invention is the arrival or removal of the film hood or banderole during the arrival or Tightening and / or peeling off the foil hood or banderole during the coating caused by the movement of rollers, wherein the outer surfaces of the rollers Move the pushed onto the gripping devices parts of the film hood or band. As a result, by controlling the speed of the rollers exactly the Aufreff- or removal speed of the film hood or band are controlled.

In a further embodiment, the lower end of the film hood or banderole in the stall phase for generating a maximum vertical stretch and a Understretched held so that the lower end of the film hood or band firmly attached to the underside of the palletized stack of goods. In an advantageous embodiment can the retention of the film hood or band by those described above Rolls are effected, which the film hood or banderole to the gripping device to press. However, other devices for holding the film hood can also be used or banderole be provided.

The device according to the invention for packaging articles with a stretch film comprises a movable in a substantially vertical direction lifting frame for Covering the film hood or banderole over the stack and provided on the lifting frame Gripping devices for gripping and stretching the film hood or banderole in in a substantially horizontal direction. Furthermore, on the gripping means Aufreffeinrichtungen for the collection and removal or banderole of the film hood from the gripping devices intended. These attachments are characterized in that they Control devices for controlling the expansion of the film hood or band in the area the top of the stack of goods, whereby a desired horizontal stretch of the Slide can be adjusted and overstretching is avoided.

In a preferred embodiment, the applicators partially enable Removing the film hood or band from the gripping devices during the substantially horizontal movement of gripping devices. This will cause the horizontal stretch the film is reduced and thin spots in the film in particular at the points to where the film over the bow-like sections at the top of the gripper runs avoided.

In a preferred embodiment, the controllers may be the peel rate during the substantially horizontal movement of the gripping means and / or the vertical movement of the lifting frame. The control takes place in Advantageously such that the stripping speed during the substantially horizontal movement of gripping devices is less than the speed of Gripping devices and / or that the removal speed during the substantially vertical movement of the lifting frame is less than the speed of the lifting frame. As a result, a certain amount of elongation of the film hood or band in vertical and horizontal direction.

In a further embodiment of the device according to the invention have the Aufreffeinrichtungen at least one roll that can be brought into contact with the lifting frame, which roll rolls up the foil hood or banderole onto the gripping device or unwinds from it.

In order to achieve maximum understretch of the film hood or banderole is in another Embodiment on each applicator a holding device provided to To hold the film in the Überziehendphase on the gripping device. The holding device may be formed by the rollers described above in one embodiment of the device be, which the film hood or band in the Überziehendphase against the Press gripping devices.

Fig. 1

eine perspektivische Ansicht der wesentlichen Teile einer Vorrichtung zum Verpacken von Gegenständen gemäß einer Ausführungsform der vorliegenden Erfindung zeigt; und

Fig. 2A - F

die einzelnen Schritte einer Ausführungsform des erfindungsgemäßen Verfahrens darstellen.

Further features, advantages and details of the invention will become apparent from the following detailed description of a preferred embodiment with reference to the accompanying drawings, in which:

Fig. 1

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

Fig. 2A - F

represent the individual steps of an embodiment of the method according to the invention.

The apparatus for packaging articles 1 shown in Fig. 1 does not comprise one illustrated supply roll for a folded film tube 3, which is unwound from the supply roll and a central packaging unit is supplied. The packaging unit has a frame, which is used for packaging the objects in the vertical direction the stack 1 is moved. From the packaging unit are for better illustration only the relevant components according to the invention shown.

As can be seen from Fig. 1, the film tube 3 via a deflection bar 4 is vertical guided down to a welding and cutting device 5, if a film hood formed shall be. In this welding and cutting device, the film tube 3 in welded and cut to a desired length, and the welded End opposite end of the film tube is provided on the four on the frame Gripping devices 8 aufgerefft and then by horizontal movement of the Gripping devices stretched in the horizontal direction, so that an opened film hood 6 forms. The gripping devices shown in Fig. 1 consist of bow-like Frame sections 8a and U-legs 8b. The bow-shaped frame sections 8 a and Uprights 8b are C-shaped and so give the corners of the film hood. Is the Forming a closed at its top film hood is not intended, the Welding omitted, and it is a piece of hose (banderole) to a predetermined Cut length. In the following, however, is spoken of a film hood.

Fig. 2A to 2E show the steps of the inventive method for packaging the Good stack 1 with the film hood 6, wherein in the Fig. Each two gripping devices. 8 are shown. As can be seen from the figures, a respective one of the gripping devices Aufreffeinrichtung 9 arranged, which the film hood on the respective gripping device defer or withdraw from it. The applicator 9 comprises a roller 10 and a Drive 11. The applicator is mounted on a support 12, which in turn a guide 14 is arranged and is horizontally displaceable. The strap piece of the gripping device 8 is attached to an arm 13. This arm is also in the guide 14 arranged and displaceable in the horizontal direction.

As shown in Fig. 2A, the film hood is made after welding and cutting 6 the impact of the same on the gripping means 8. For this purpose, the arm 13 in moves a position in which the cross-section of the frame is less than the outline of the The stack. Further, the outer surfaces of the rollers 10 come into contact with the outer sides the foil hood. Turn the left hand gripper roller clockwise and turning the roller of the right gripper counterclockwise (such as indicated by the arrows in Fig. 2A) can now the film hood on the bow-like Frame section of the gripping device 8 aufgerefft. In Fig. 2B, the state of Foil hood after the impact on the gripping device 8 shown.

To stretch now the film hood 6 in the horizontal direction, the gripping devices 8 moves in the horizontal direction to the right or left. This process step is apparent from Fig. 2C, wherein the movement of the gripping means by arrows is indicated. To prevent the film hood at the corners or gripping engagement area exposed to such strong tensile forces that arise in the film thin spots, which can lead to damage of the film, both rollers 10 of the Aufschiebeeinrichtungen 9 in the opposite to the previous method step opposite Direction moves, causing a slow unwinding of the film hood during the horizontal Stretching is possible. Here it is essential that the speed the rollers is set such that the unwinding speed of the gripping means is less than the horizontal speed of the gripping devices, otherwise not the desired stretch could be made possible. Overall, this process step becomes achieved that the horizontal stretch over the conventional devices is reduced in a controlled manner.

After the horizontal stretching is now the frame is vertically downwards moved, the rollers 10 until the contact of the film hood with the upper end of the Stack of goods do not rotate. This method step can be seen in FIG. 2D.

In Fig. 2E are two process steps during the coating of the film hood over the Good stack shown, the film hood is in contact with the stack. As soon as the Film hood touches the stack, in addition to the vertical movement of the frame one Rotary movement of the rollers 10 of the gripping means 8, wherein the role of the left Gripping device counterclockwise and the role of the right gripping device in Moves clockwise. The rotation of the rollers causes the film hood to roll off controlled by the gripping device, and thereby becomes a desired vertical stretch reached the film hood. The speed of the rollers is set in such a way that the unwinding speed of the film hood from the gripping device is less than the vertical speed of the lifting frame, otherwise not the desired vertical stretch could be generated.

Fig. 2F shows the process step that ends the coating process. After the Frame with the respective gripping device below the lower end of the stack is located and the film hood largely unrolled from the respective gripping device is, the lower end of the film hood is held on the gripping device to thereby to allow a maximum vertical stretch and a sub-stretch. This will the firm application of the lower end of the film hood to the stack after slipping allows the gripping devices.

It is also conceivable that the gripping devices with pressed rollers on each other move to below the pallet, then the film, which is already partially under the Pallet has set completely free. During the movement of gripping devices inside under the charge, the film is under the action of the rollers with a lower Speed released as the speed of moving horizontally Gripping devices.

Claims (14)

1. A method of packaging articles, especially a palletised stack of goods (1), with a tubular stretch film, especially a tubular stretch film guided in web form as a sided tube, comprising the steps of:

   forming a film hood (6), or a tubular banderole, matched in length to the goods to be packaged;

   reefing the film hood (6) or banderole onto a plurality of substantially horizontally movable gripping means (8) of a substantially vertically movable lifting frame;

   tentering the reefed film hood (6) or banderole in a substantially horizontal direction by moving the gripping means (8), so that the tentered opening of the film hood (6) or banderole is larger than the plan area of the article (1) to be packaged, and the film hood (6) or banderole being stretched in a substantially horizontal direction;

   drawing the film hood (6) or banderole over the article (1) by means of the substantially vertical movement of the lifting frame, the film hood (6) or banderole being drawn off the gripping means (8) and stretched in a substantially vertical direction;

   characterised in that the tension of the film hood (6) or banderole during tentering at the top of the stack of goods (1) is controlled.
2. A method according to claim 1, characterised in that, during tentering, the film hood or banderole is partially drawn off the gripping means (8) again by reefing means (9).
3. A method according to claim 2, characterised in that the drawing-off speed of the film hood (6) or banderole during tentering is lower than the speed of the substantially horizontal movement of the gripping means (8).
4. A method according to any one of the preceding claims, characterised in that the drawing-off speed of the film hood (6) or banderole during drawing-over of the film hood (6) or banderole is lower than the speed of the substantially vertical movement of the lifting frame.
5. A method according to any one of the preceding claims, characterised in that the reefing and drawing-off of the film hood (6) or banderole during reefing and tentering and/or the drawing-off of the film hood (6) during drawing-over is effected by the movement of rollers (10), the outer surfaces of the rollers shifting the film hood (6) which has been pushed onto the gripping means (8).
6. A method according to any one of the preceding claims, characterised in that the film hood (6) or banderole is firmly held on the gripping means (8) during the end phase of the drawing-over process.
7. A method according to claim 6 in combination with claim 5, characterised in that the firm holding of the film hood (6) or banderole is effected by means of the rollers (10) which press the film hood (6) against the gripping means (8).
8. An apparatus for packaging articles, especially a palletised stack of goods (1), with a tubular stretch film, especially a tubular stretch film guided in web form as a sided tube, comprising:

   a substantially vertically movable lifting frame for drawing a film hood or tubular banderole over the stack of goods (1);

   a plurality of gripping means (8), provided on the lifting frame, for gripping and stretching the film hood (6) or banderole in a substantially horizontal direction;

   reefing means (9), provided on the gripping means (8), for reefing on the film hood (6) or banderole and drawing it off the gripping means (8);

   characterised in that the reefing means (9) comprise control means for controlling the stretching of the film hood (6) or banderole during the tentering at the top of the stack of goods (1).
9. An apparatus according to claim 8, characterised in that the reefing means (9) are able to draw the film hood or banderole partially off the gripping means (8) during the substantially horizontal movement of the gripping means (8).
10. An apparatus according to claim 9, characterised in that the drawing-off speed during the substantially horizontal movement of the gripping means (8) and/or during the vertical movement of the lifting frame can be controlled by the control means.
11. An apparatus according to claim 9 or 10, characterised in that the control means control the drawing-off speed of the film hood or banderole in such a manner that it is lower during the substantially horizontal movement of the gripping means (8) than the speed of movement of the gripping means (8) and/or in such a manner that it is lower during the substantially vertical movement of the lifting frame than the speed of movement of the lifting frame.
12. An apparatus according to any one of claims 8 to 11, characterised in that each reefing means (9) comprises at least one roller (10) which can be brought into contact with the lifting frame and which is able to roll the film hood (6) or banderole onto and off the respective gripping means (8).
13. An apparatus according to any one of claims 8 to 12, characterised in that the reefing means (9) has a holding device for firmly holding the film hood (6) or banderole on the respective gripping means (8) in the end phase of the drawing-over process.
14. An apparatus according to claim 13 in combination with claim 12, characterised in that the holding device comprises the at least one roller (10) which presses the film hood (6) or banderole against the gripping means (8) in the end phase of the drawing-over process.

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