EP2621717B1 - Device and method for producing sacks from tube pieces - Google Patents

Description

The invention relates to a device for producing sacks of pieces of hose, which preferably comprise woven fabric of stretched plastic tape according to the preamble of claim 1 and a method according to the preamble of claim 11.

Such a device and such a method are last from the publication of the patent application WO 2010/054955 become known to the applicant. The ends or at least one end of the hose pieces are folded over by 90 degrees. The resulting folding line is then impressed by an embossing device in the tubing, so that the restoring force is reduced and the subsequent bottom opening and bottoming done overall trouble-free and ultimately the floors also correspond to the desired shape.

The bags made in this way fully meet the requirements mentioned. However, another problem has come to light. In dump tests of such bags, which would be additionally filled, the sacks have just burst at the fold line.

The result was the task to improve the apparatus and method for the production of sacks in such a way that the bursting of filled bags is avoided.

The object is achieved by a device according to claim 1 and a method according to claim 11.

Accordingly, a transfer device is provided, with which areas of both walls of one end can be moved by more than 90 degrees around the Bodenfalzkante. This device serves to fold back the end of the piece of tubing around the fold edge. When the tube piece has passed through this device, an embossing element and a counter element act on the end of the tube piece, wherein these two elements are in touching contact with the same wall of the tube piece. However, the two elements act on the two different sides of the fold line. In this way, the tube piece ends are folded over in the regions of the fold lines by 180 degrees and pressed against each other, so that the fold line is formed stronger. The folding by means of the transfer device can serve to already convert the hose piece end by almost 180 degrees, so that the hose piece end without interference enters the area between embossing element and counter element.

The present invention was based on the finding that the embossing element according to the WO 2010/054955 With its rather sharp edge, the fabric has been badly damaged, so that it could no longer withstand the burdens of falling and is torn. The embossing device according to the present invention acts only by applying a strong pressure to the folding line. In this case, the embossing element and counter element bear against the sharp edge with a significantly larger surface on the hose piece, so that damage and thus weakening of the fabric are avoided. With regard to the proper production of sacks suitable for the format, no disadvantages have become apparent to which the said transfer device substantially contributes.

In a preferred embodiment of the invention, the embossing element and the associated counter element comprise rollers. In the roller gap, therefore, the hose piece end runs, wherein the fold line preferably extends centrally of the rollers.

It is expedient to provide the outer surfaces of the embossing element and the counter-element with an elastic coating in order to avoid slippage or displacement of the bag material during the embossing process.

In an advantageous embodiment of the embossing element and / or the counter element is associated with a drive, with which said element or the two said elements are driven at a peripheral speed which is greater than the transport speed of the hose pieces. This slightly greater speed is referred to as "overfeed". The drive can be an independent motor for the embossing element and / or the counter element, which can be synchronized with the main drive of the device. Of course, both elements can be driven by its own drive. The drive can also be done by the main drive of the machine, which preferably also drives the transport device for the hose pieces. Between the drive and the said elements then a transmission gear is provided. The overfeed serves to tighten the length of tubing in the direction of transport, so that no wrinkles occur and these may be imprinted into the tubing.

It is particularly advantageous if only one of the elements is assigned a drive and the other element can be driven by frictional engagement. Preferably, the drive is on the counter element. Embossing element and counter element can be provided to produce the frictional engagement on their surfaces with O-rings, which are raised relative to the peripheral surfaces.

In a further advantageous embodiment, the embossing element or the counter element can be adjusted with a force applying device against the other element. The element which can be subjected to a force is preferably the embossing element. The engageable element is preferably mounted in one end of a lever arm, on the other end of the Kraftbeaufschlagungseinrichtung acts. The force application device may be a spring element, a piston-cylinder unit or a simple mass, which is under the influence of gravity include. By a suitable choice of force, the fold line can be impressed sufficiently strong, without the tissue is damaged.

In order to set the folded edge before the embossing device acts on the folded edge, a folding element is provided, which has a folding edge defining the working edge. This working edge runs parallel to the transport direction of the hose pieces. In addition to the folding element, a further guide element is provided as part of the transfer device, with which the end of the hose piece can be folded around the working edge of the folding element. In this way, the end of the tube piece can already be largely folded back on itself. The folding element extends wedge-shaped up to the folded edge of the hose piece. The guide element, however, is arranged inclined to the transport direction of the hose pieces, wherein it overlaps with the folding element in the course of transport.

Of great advantage is further when the folding element is associated with a tension element, with which causes the hose piece material is pulled against the working edge of the folding element, so that the folded edge is formed at the predetermined position of the hose piece. The tension element may be a roller whose axis of rotation is inclined both against the extension direction of the hose piece and against the transport plane thereof. The pulling element can be acted upon by a force, so that it is pressed against the folding element.

Further embodiments of the invention will become apparent from the subject description.

Fig. 1

Prinzipskizze einer Vorrichtung zur Herstellung von Gewebesäcken

Fig. 2

Perspektivische Ansicht einer Bodenöffnungsstation in einer erfindungsgemäßen Vorrichtung

Fig. 3

Ansicht III - III aus der Figur 2

Fig. 4

Ansicht IV - IV aus der Figur 3

Fig. 5

Ansicht V - V aus der Figur 3

Fig. 6

Ansicht VI - VI aus der Figur 3

Fig. 7

Ansicht VII - VII aus der Figur 3

Fig. 8

Ansicht VIII - VIII aus der Figur 3

Fig. 9

Ansicht IX - IX aus der Figur 3

The individual figures show:

Fig. 1

Schematic diagram of an apparatus for the production of tissue sacks

Fig. 2

Perspective view of a floor opening station in a device according to the invention

Fig. 3

View III - III from the FIG. 2

Fig. 4

View IV - IV from the FIG. 3

Fig. 5

View V - V from the FIG. 3

Fig. 6

View VI - VI from the FIG. 3

Fig. 7

View VII - VII from the FIG. 3

Fig. 8

View VIII - VIII from the FIG. 3

Fig. 9

View IX - IX from the FIG. 3

The Fig. 1 schematically shows individual steps for processing a fabric tube to bags, as done in bag making device 1.

First, the fabric tube 2 is fed to the sack manufacturing device 1. This is advantageously done by unwinding of a fabric 3 forming a fabric tube in a unwinding device 4. Then, the tube 2 can experience the so-called opening in the opening station 5. In this case, the fabric tube is guided around an inner tool, which separates the two layers from each other, so that the layers, if they were glued together in one of the manufacturing steps of the hose, separate. Only with separate layers can it be ensured that the following production steps can be carried out properly. Afterwards, the separate material layers of the hose are put back on top of each other.

The fabric tube is now fed to the cross-cutting device 6, which separates the fabric tube into individual pieces of hose.

Subsequently, a change of the original transport direction z, in which the tube or pieces of tubing were transported in the direction of their longitudinal axes, in the new transport direction x, so that the hose pieces now no longer in the direction of z hose longitudinal axis (hereinafter also extension direction of the hose pieces called ), but are transported transversely thereto, so that the ends of the hose pieces are laterally accessible for the purpose of molding the floors.

In the following station, the bottom opening station 8, both ends of each tube piece are opened and the so-called ground rectangles are laid. In the following valve station 9, a valve is placed and secured on one of the two open ends. The open floors are now closed in the bottom closing station 10, wherein two tabs are placed on each other and permanently connected to each other, for example by welding. The conclusion of the actual Sackherstellprozesses forms the application of a ground cover sheet on the floors in the cover sheet station 11. For this purpose, the cover sheets can also be welded. The finished bags are then placed on the bag stack 12 and transported away from there on unspecified manner.

The Fig. 2 shows details of a bottom opening station 8 in a device according to the invention The tube pieces 13 are transported flat by means of a transport device in the direction x on the surface of a support 14, for example on the surface of a table, ie substantially horizontal. The transport preferably takes place at a uniform speed, ie in a continuous transport. To open one end 15 of the tube piece, this end is first brought from the horizontal position to a vertical position. To allow this folding, the hose piece must be counteracted.

For this purpose, the hose piece 13 is threaded under a folding element representing the counter position. This folding element 16 is firmly attached to the machine frame or on the support. This means that the tube pieces 13 move relative to the folding element. In order to prevent the hose pieces from getting caught on the folding element 16, an additional transport device, for example a conveyor belt 30, is provided below the folding belt (see FIGS. 6 to 9 ). In the region of the folding element 16, one or more rollers may be provided to press the respective piece of hose to the conveyor belt 30 can. If the hose piece 13 is threaded, it is then guided past a guide element 17, for example a baffle. This baffle is shaped that the end 15 of the tube piece 13 beyond the fold line 27 (which represents the bottom center line) is successively brought into a vertical position.

Subsequently, the tube piece 13 passes to the actual bottom opening device 18, which is shown only schematically in this figure. On the way to the bottom opening station, the tube piece passes through the embossing device 26. Here, the end 15 of the tube piece 13 is further transferred by one or more guide elements 25, so that it is folded back onto the tube piece. The folding back particularly concerns the area near the fold line, while the other areas may remain in a vertical position. This is particularly advantageous because the entire end must be in a vertical position again for the bottom opening. After the folding back is done, the tube piece 13 passes the pair of rollers, which is formed from a stamping element 28 and a counter-element 29.

In the bottom opening device 18, two suction bars are provided, which engage on both sides of the folded-up end and are guided in or against the direction z, so that the material layers are separated from each other. The interior of the end 15 of the tube piece 13 is now accessible. Spreading elements now engage in this interior, which push the material layers further apart until they are horizontal again. This situation is illustrated by the open bottom 19.

The opening of the second end 15 'of the tube piece 13 takes place in the same way. In particular, the embossing device is the same. The processing of the second end 15 'is, however, offset for processing the first end 15. The first end is already opened in the bottom opening device 18, while the second end 15' is guided under the folding belt 16 '. By means of the guide element 17 'and the bottom opening device 18', the open bottom 19 'is generated in the manner described above. Before the tube piece 13 reaches the second bottom opening device 18 ', it passes through the embossing device 26'. A staggered arrangement of the components is advantageous when producing bags with very small center spacings should be. In this case, the embossing means 26, 26 'may be arranged offset from one another. One possible arrangement would be that the (second) embossing device 26 'is arranged opposite the (first) bottom opening device 18.

When leaving the bottom opening station 8, the piece of tubing with open bottoms 19, 19 'is present, wherein all components of the opened bottoms are located substantially in the plane of the support 14.

A particular aspect of the bottom opening station 8 is the fact that each bottom opening device 18, 18 'is supplied with torque by its own drive. This is illustrated by the motor 22 on the bottom opening device 18. The corresponding motor on the bottom opening device 18 'is not visible in the illustrated view. The motor of a bottom opening device 18, 18 'primarily supplies the suction bars with a drive torque, so that they can move the material layers away from one another. Also, the spreading elements are powered by this engine with torque. These drives of the floor opening devices 18, 18 'can each drive one or both rollers 28, 29 of the embossing devices 26, 26' via a transmission.

The conclusion of the bottom opening devices 18, 18 'form the pressure rollers 23, 23', which serve the purpose of compressing the freshly opened soils and thus to fix in their position. The resulting in the context of the bottom opening creases are thereby further struck and then form correct folding edges, so that the tendency of the soil decreases, to straighten up again. As a counter-pressure element to the pressure rollers 23, 23 'serve either the support 14 or the counter-pressure rollers 24, 24'. The pressure rollers 23, 23 'are in the FIG. 2 arranged in the transport direction x seen at the same height. These rollers 23, 23 'can also be arranged offset from one another, so that the open floors can be pressed immediately after the opening process in the manner described.

The FIG. 3 Now shows the view III - III from the FIG. 2 and thus details of the embossing device 26. In this view, however, was omitted for the sake of clarity on the presentation of hose pieces. In this view, first the support 14, the folding element 16 and the guide element 17 can be seen. In the region in which the guide element 17 has brought the end of the hose piece 13 in a vertical position, a further guide piece 31 is arranged, which prevents a return of the end of the hose piece in the region of its folded edge. In the further course of the transport of the hose pieces in the transport direction x, the guide member 25 is mounted on the guide piece 31, which can be done for example by means of screws. The guide member 25 is followed by a pull roller 32, with which the end of the hose piece are pulled substantially in the extension direction of the hose pieces z, so that they touch the working edge 33 of the folding member 16. If this contact was not ensured, the positionally accurate introduction of the folded edges could not be guaranteed. The axis of rotation of the tension roller is inclined. In this case, it comprises a component in the -x direction, in the z direction and also in the y direction. The peripheral surface is parallel to the inclined surface 34 of the folding element 16 (see FIG. 6 ).

After the folded edge 27 of the tube piece 13 has been determined in the manner described, the piece of tubing 13 runs into the gap between the embossing roller 28 and the counter-roller 29. The counter-roller 29 is driven via a tension element, for example via a toothed belt 35, by a drive with overfeed. The toothed belt 35 transmits its driving force to a gear 41, which is fixedly connected to the roller 29. The embossing roller 28 presses against the peripheral surface of the counter-roller 29 with a defined force. For this purpose, the embossing roller 28 is freely rotatably mounted in one end of a lever arm 36. The lever arm 36 in turn is rotatably mounted in a frame-fixed support 37. The second end of the lever arm 36 is connected to a piston-cylinder unit 38, which applies a force, which is represented by the arrow F. The piston-cylinder unit can be operated with compressed air, whereby the air pressure can be about 3 bar. Due to the mentioned Force, the fold line 27 can be embossed sufficiently well without the material of the hose pieces 13 is damaged.

The embossing roller 28 is advantageously also driven, which is based on the FIG. 4 is explained in more detail. If this were not the case, it would first have to be accelerated by a piece of hose 13, but this could result in damage to this piece of hose. However, the drive of the embossing roller 28 takes place via a frictional engagement with the counter-roller 29. Both rollers 28 and 29 have on their outer circumference in each case an O-ring 39 and 40, which roll on each other. The O-rings are arranged so that they do not come into contact with the hose piece 13 (see FIG. 9 ). When a piece of tubing 13 is in the roll nip, as shown in FIG FIG. 9 is shown, the contact between the O-rings can be canceled. At this moment, the embossing roller 28 is moved by the hose piece 13. The transmission of a slight torque through the tube piece 13 on the roller 28 to compensate for the rolling resistance is in contrast to the acceleration of a stationary roller 28 is unproblematic and leads to no significant damage to the tube piece thirteenth

The FIG. 5 shows the view IV - IV from the FIG. 3 , In this figure, the obliquely arranged to the transport direction x guide member 25 can be seen, which overlaps the folding element 16 in the course of the transport direction x. Also, the tension roller 32 and their arrangement in the room are clearly visible.

The FIGS. 6 to 9 show different, in the FIG. 3 shown views, each now the hose piece 13 is shown. With these figures, the sequence of functions for embossing the fold line 27 is illustrated. The FIG. 6 shows still the horizontally disposed end 15 of the hose piece 13, after it has been threaded under the folding member 16. In dashed line, the edge 42 of the tube piece 13 can be seen, on which the upper wall 43 and the lower wall 44 are connected to each other.

The tube piece 13 is transported by means of the transport device 45, which, for example, comprises the tube piece 13 between two transport belts 46 and 47 circulating at transport speed. To support the proper feed of the tube piece 13 in the region of the folding element 16, a further conveyor belt 30 may be provided here. It is the wedge-shaped shape of the folding element 16 can be seen, which includes the working edge 33 at its thinnest point, which determines the position of the later folded edge 27. The location of the fold edge is shown by the broken line 48. The hose piece 13 is already in the region of the guide element 17.

In the FIG. 7 the end 15 of the tube piece 13 was brought by the guide element 17 in a vertical position and thus bent about the folded edge 27.

The FIG. 8 shows the situation in which the guide member 25 has acted on the end 15 of the hose piece 13 and further folded around the working edge 33 of the folding element 16. The angle at which the end is folded is more than 90 degrees, preferably more than 135, in particular more than 150 degrees. Also visible is the guide piece 31, which prevents rolling of the folded edge 27 on the outside, that is, counter to the direction z. Regions of the end 15 can be held in a vertical position by means not shown guide means.

The final one FIG. 9 shows the action of the embossing roller 28 and the counter-roller 29 on the wall 44 of the hose piece 13. The embossing roller 28 touches the wall 44, which can be considered here as part of the end 15 of the hose piece 13, while the counter-roller on the wall 44 of the hose piece 13 acts. Between these two effective areas, the folded edge 27 is arranged. The wall 43 is not touched by the rollers 28, 29. LIST OF REFERENCE NUMBERS 1 Bag-making apparatus 2 Gewebeschlauch 3 reel 4 handling facility 5 opening station 6 Transverse cutting device 7 8th Bottom opening station 9 valve station 10 Bottom closing station 11 Cover Station 12 bag stack 13 hose Connector 14 edition 15 15 ' Piece of hose end 16 16 ' scoring element 17 17 ' vane 18 18 ' Bottom opening device 19 19 ' Open ground 20 21 22 engine 23 23 ' pressure roller 24 24 ' Backing roll 25 guide element 26 26 ' embosser 27 fold line 28 embossing element 29 counter-element 30 conveyor belt 31 guide piece 32 pull roll 33 working edge 34 Sloping surface of the folding element 16 35 toothed belt 36 lever arm 37 Frame-fixed support 38 Piston-cylinder unit 39 O-ring 40 O-ring 41 gear 42 Edge of the hose piece 13 43 Upper wall 44 Lower wall 45 transport means 46 conveyor belts 47 conveyor belts A Bottom center distance F Representation force x transport direction y Z hose longitudinal axis

Claims (11)

1. Apparatus (1) for producing bags from flexible-tube pieces which comprise preferably woven fabric made of drawn plastics strips and are made up of two walls (43, 44) located one above the other, wherein the apparatus (1) has at least the following devices provided in it:

   - a transporting device (45), by means of which the flexible-tube pieces can be transported to processing stations (8, 9, 10, 11) in a transporting direction (x), which runs transversely to the direction (z) in which the flexible-tube pieces extend,

   - a bottom-opening station (8), by means of which open end portions can be produced by virtue of regions of at least one wall of the flexible-tube piece being folded over around bottom-folding edges at at least one end of a flexible-tube piece,

   - a closing-up station, by means of which the open bottom rectangles can be closed up to form bottoms by virtue of parts of the walls and/or flaps being folded over around further folding edges,

   - a stamping device (26, 26'), by means of which at least part of the bottom-folding edge and/or of the further folding edges can be stamped into the flexible-tube pieces, and which comprises a stamping element (28) and an associated mating Element (29),

   characterized

   - in that a folding-over device is provided, by means of which regions of the two walls can be folded over by more than 90 degrees around the bottom-folding edges, and

   - in that the stamping element (28) and the associated mating element (29) are arranged downstream of the folding-over device, wherein the folded-over walls can be introduced between the stamping element (28) and mating element (29) such that the latter are in contact with the same wall of the flexible-tube piece.
2. Apparatus (1) according to Claim 1,
   characterized in that
   the stamping element (28) and associated mating element (29) are rollers.
3. Apparatus (1) according to one of the preceding claims,
   characterized in that
   the outer surface of the stamping element (28) and that of the mating element (29) are provided with an elastic coaling.
4. Apparatus (1) according to one of the preceding claims,
   characterized in that
   the stamping element (28) and/or the mating element (29) are assigned a drive, by means of which the element or the elements can be driven at a circumferential speed which is greater than the speed at which the flexible-tube pieces are transported.
5. Apparatus (1) according to one of the preceding claims,
   characterized in that
   the stamping element (28) or the mating element (29) can be driven by the respectively other element by way of a friction fit.
6. Apparatus (1) according to one of the preceding claims,
   characterized in that
   the stamping element (28) or the mating element (29) can be positioned against the other element by way of a force-exerting mechanism.
7. Apparatus (1) according to one of the preceding claims,
   characterized in that
   the bottom-folding edge can be defined by at least one folding element (16, 16'), of which the operating edge runs parallel to the transporting direction (x) of the flexible-tube pieces.
8. Apparatus (1) according to one of the preceding claims,
   characterized in that
   at least one guide element (25) is provided, by means of which the walls of the flexible-tube piece can be folded over around the operating edge of the folding element (16, 16').
9. Apparatus (1) according to one of the preceding claims,
   characterized in that
   the folding element (16, 16') is assigned a pulling element (32), which acts on the walls of the flexible-tube piece such that said walls butt closely against the folding element (16, 16').
10. Apparatus (1) according to the preceding claim,
    characterized in that
    the pulling element (32) comprises a roller, of which the axis of rotation is inclined both in relation to the transporting plane (x-y) and in relation to the direction in which the flexible-tube pieces extend.
11. Method for producing bags from flexible-tube pieces which comprise preferably woven fabric made of drawn plastics strips and are made up of two walls (43, 44) located one above the other, wherein at least the following steps are provided:

    using a transporting device to transport the flexible-tube pieces to processing stations (8, 9, 10, 11) in a transporting direction (x), which runs transversely to the direction (z) in which the flexible-tube pieces extent,

    using a bottom-opening station (8) to produce open end portions by virtue of regions of at least one wall of the flexible-tube piece being folded over around a bottom-folding edge at at least one end of a flexible-tube piece,

    using a closing-up station to chose up the open bottom rectangles to form bottoms by virtue of parts of the walls and/or flaps being folded over around further folding edges,

    using a stamping device (26, 26'), which comprises a stamping element (28) and an associated mating element (29), to stamp at least parts of the bottom-folding edge and/or of the further folding edges into the flexible-tube pieces,

    characterized

    in that a folding-over device is used to fold over regions of the two walls by more than 90 degrees around the bottom-folding edges, and

    in that the stamping element (28) and the associated mating element (29) are brought into contact with the same wall of the flexible-tube piece.

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