EP0727352A2 - Method for manufacturing self-standing bags - Google Patents

Abstract

The tubular bag (7) which is flat folded inwards at least once at its side parts which determine the width (5) of the bag (1) is closed at the bottom by a cross seam forming a fin (8). The bag is opened and a base shaping ram (11) is inserted down to the bottom so that the bag base (15) can be shaped by bringing in the shaping slide which has indentations corresponding to the fold edges. The bag base is then pressed between the ram and the shaping slide. The fin is turned over and connected to the base by using a counter holder which supports the bag base inside the bag. The flat material used for the bag has heat sealable material at least on the inside.

Description

The invention relates to a method for producing, filling and closing a packaging bag and the packaging bag suitable for this.

A large number of consumer goods, in particular foodstuffs, are packaged in bags, with the bags being produced, filled and closed mechanically.

Pure paper or coated paper is very often used as the bag material.

The bags used for filling can either be produced separately before the filling process in a separate system, usually by a specialized bag manufacturer, and entered into the system for filling and closing, or the bags can be found online, i.e. in the system directly upstream of the filling station, just-in-time made from sheet material from the roll and then filled, sealed and further packed.

The variety of bags used differs primarily in the exactness and durability of their shape, especially in the bottom area, and thus also in their later stability and shape retention after opening and repeated reclosing by hand, as is the case with the slow use up of the goods contained is usually the case.

Depending on the type of goods to be filled, it makes sense to achieve a high level of dimensional stability of the packaging bag, especially in its base area, especially for stackable, but inherently less dimensionally stable individual products for a smooth filling process.

So far, a high level of dimensional stability and dimensional accuracy in the lower area of the bag has been achieved primarily through a complicated and exact, multi-overlapping gluing in the bottom area, for example through separately glued-on floor reinforcements, etc. Such, dimensionally stable and precisely folded bags along their longitudinal edges etc. have so far been created in separate production lines for such bags, delivered to the filling location, and introduced there into the filling and packaging system, since a just-in-time preparation due to the complexity of the Bag production with the same cycle time as the filling process is not possible, and the parallel operation of several such very expensive bag production lines is not economically worthwhile.

On the other hand, the bags made from the roll online with the filling and packaging process usually have a fin which is formed and taped below the bottom of the bag and which represents the closure of the bag tube, but which is rather detrimental to the accuracy and durability of the bag bottom.

It is therefore the object according to the present invention to provide a method for producing, filling and closing packaging bags and a bag suitable therefor, despite the exact shape and high dimensional stability of the packaging bag, especially in the bottom area of online production of the bags with little technical and financial expense from sheet material from the roll before the filling and further packaging process is possible.

This object is achieved by the characterizing features of claim 1. Advantageous embodiments result from the subclaims.

The production from a flexible, but usually not stretchable surface material - for the sake of simplicity, the concrete use of paper is assumed - from the roll is possible by basically the known production of bags by creating an endless Bag tube is selected from the paper tape and the production of bags closed on the bottom side by means of a fin from the endless bag tube.

The exact shaping and keeping of shape is achieved by a certain type of bag formation as well as interacting process steps:

Before filling, the bag in the bottom area is not simply pulled apart or pressed apart by the filling material, but the bottom area is actively shaped by means of a stamp and counter-punch, with the longitudinal edges of the bottom, which connect the two end gussets, above the inside of the bag arranged, raised fold edges and from the outside pressing, correspondingly shaped recesses.

Furthermore, this pressing of the bottom of the bag additionally works at an elevated temperature of the paper or its coating material, so that after the temperature has been reduced to normal ambient temperature after the pressing of the bottom region, additional stabilization occurs due to the cooled coating. The temperature of the coating or of the paper reached in this case is lower than that of the individual sealing processes carried out during the production or sealing of the bag, in which the individual layers of the paper or its inner and outer coatings are bonded to one another.

These sealing processes are partially carried out by means of the known method of heat sealing, at least the corresponding, affected coatings having to consist of a heat-sealable material, but at least some of the sealing processes, preferably even all sealing processes, are carried out by means of ultrasound, the coating materials concerned or the used surface material itself must connect when subjected to ultrasound, z. B. by at least pastry, preferably even become liquid, and thereby stick to one another, or also through increased material diffusion.

In addition, the fin forming the bottom closure of the packaging bag and striving downwards towards the outside, especially in the case of narrow bags, is made relatively large, so that after it has been folded down into the plane of the bag bottom, with a central arrangement of the fin in the bag bottom, essentially a whole half of the Covers the bag bottom and is additionally stabilized by the subsequent connection to the bag bottom. This connection also takes place using a counter-holder in the interior of the bag in order to no longer have a negative influence on the shape of the bag bottom which has already taken place.

Both the bottom form stamp, which is inserted into the inside of the bag for pressing the bottom of the bag, and the counter-holder, which is used when connecting the folded fin to the outside of the bag bottom, consists of more than one part, for insertion from the open top of the bag to facilitate her, and only shortly before reaching the bag bottom to expand these parts to the actual dimensions of the bag bottom.

The bottom die and the counterholder therefore preferably consist of two parts, which are almost as long as the length of the bag bottom, but can be moved relative to one another in the width of the bag. Since the form stamps are inserted into the bag from the open side by means of a mechanism, both are preferably connected to the ends of a V-shaped scissor linkage, the center of which is coupled to a pneumatic unit mounted on the mechanism, so that shortly before the desired one is reached End position a spreading of the V-shaped linkage and thus a moving apart of the two parts of the bottom form punch or the counter-holder to the width of the bag bottom is achieved. Likewise, the stamp for shaping the base area can also be implemented beforehand.

The side parts of the bag are kept apart, preferably by means of suction cups distributed over their surface and attacking from the outside, the free upper edge of the bag preferably being additionally opened by means of mechanical openers in the form of cranked sheets which can be pivoted into the upper region of the bag being held.

This prevents damage or incorrect shaping of the bag under the action of the mechanical active parts.

Since the fin - with a central arrangement with respect to the bag bottom - should support half of the bag bottom as completely as possible after folding, the bag tube is made for the manufacture of a bag from the endless bag tube by means of a known K transverse seam and subsequent K seams locked. Due to the simple inward folding of the side areas of the later bag during the manufacture of the flat-folded, endless bag tube, two layers of paper lie one above the other in the central area over the cross-section of the flat-folded bag tube, but four layers in the side areas in which the side parts are folded.

In order to achieve a secure seal and therefore a very high level of tightness - preferably dust tightness and water tightness - of the seams closing the bag downwards, the K-transverse seam, which runs from one outer edge of the flat bag tube to the other, is successively from each side of the bag tube here once and thus executed twice. When sealing the oblique K-seams, two of which are on top of each other because of the 4-layer paper there, a separating plate is inserted between the two middle layers of paper, so that only two layers of paper are connected to each other via their inner coating.

In the folded side areas of the bag tube, all four layers are thereby firmly connected to each other, too the two middle layers of the side parts folded inwards against each other.

However, this transverse K cross seam does not - as usual - also form the lower free end of the fin, but due to the greater length of the fin, a further transverse seam is arranged along its free end, but this is no longer necessarily from both sides of the bag tube and so that must be run twice.

All the seams just described can be made using the conventional heat sealing technique, i.e. usually using electrically heated sealing jaws, which are pressed onto the flat folded bag tube for a limited time at the appropriate position either directly or via a teflon tape that prevents them from sticking. For this purpose, the inner and outer coating of the paper used must be sealable or heat-sealable.

On the other hand, attaching the folded fin to the underside of the bag bottom by means of heat sealing is problematic, since in order to optimize the dimensional stability of the bottom, a connection of the folded fin in its front area and not only along its outer longitudinal edge to the bag bottom is absolutely necessary.

If you tried to do this by applying a heated, heat-sealing jaw, for example along the longitudinal free outer edge of the fin, the end faces would have to be heated through the four layers of thick fin, but still sufficiently heat the underlying coating on the outside ensure the bottom of the bag. In the middle, the two layers of the fin would still have to be used for heating.

Quite apart from the different temperature requirements in these two areas due to the different number of layers to be overcome this would lead to the fact that in order to achieve the correct sealing temperature between the fourth layer of the fin and the underlying floor on the outside of the folded fin, ie its first layer, a significantly higher temperature than the necessary sealing temperature would have to be applied. Such a high temperature would heat the outer paper layers and their outermost coating, which was visible from the outside, to such an extent that damage and thus an exterior of the bag that would be unreasonable from an optical point of view would be the result.

For this reason, the connection is not made by heating by means of heat conduction, but by exposure to ultrasound, as is already known for the welding of plastic films etc.

Apart from an energy saving of more than 80% compared to the use of heat sealing jaws, the depth effect of the ultrasound can be influenced by means of appropriate control of the ultrasound exposure, and the temperature at the sealing point, for example, can be influenced much more precisely than when sealing with hot, contracting sealing jaws below the fourth layer of the folded fin.

The ultrasonic waves are emitted by so-called sonotrodes, which are pressed under pressure on the bag - using a counterholder that presses against it from the other side - with 20 to 50, preferably 30 to 40 Kp.

For fastening the fin to the bottom of the bag, on the one hand a sealing seam that only extends in the two-layer, central area along the outer edge of the fin, and two sealing seams lying parallel to the width of the bag bottom along the front outer edge of the fin are used.

When using both the usual heat sealing and ultrasonic sealing, this must be the inner and The outer coating of the paper used can be both heat sealable and ultrasound sealable.

Furthermore, to improve the visual appearance of the bags, the longitudinal seam of the bag tube is also produced differently than previously:

The outer edges of the paper strip, which are formed into a bag tube, not only overlap easily, but - as is also known in principle - three or even four times, by double-folding an edge area of the paper strip and therefore having three layers. The uppermost layer of this overlapped area is overlapped by the other edge of the paper web and sealed with it by slowly pulling the endless bag tube under a heated sealing jaw and heating the longitudinal seam sufficiently. In order to avoid sticking to the sealing jaw, a quickly replaceable Teflon tape is preferably arranged between the sealing jaw and the bag tube.

With this known method of producing the longitudinal seam, however, an exact alignment of the outer edge of the paper web with the edge of the overlapped area is never entirely possible, which is why the visible outer edge of the paper web still protrudes 1 - 3 mm beyond the edge of the three-layer, overlapped area.

Since the sealing takes place in the conventional manner only in the multilayered overlapping area, and because of the missing intermediate layers it cannot also extend to the protruding, only single-layered edge area on the free edge of the paper web, this is usually loose, can be during packaging or are put up by the consumer while the filling material is being used up and is therefore not visually appealing or a constant possibility of damage to the longitudinal seam of the bag.

To avoid this, the protruding edge area and the underlying surface of the bag tube, which is used for opposite edge of the paper web is to be heated, additionally and separately, for example by means of a hot air blower, if necessary after establishing a sufficient distance between these two layers by means of a mechanical spacer wedge inserted between them.

Subsequent pressing by means of pressure rollers etc. also results in an adhesive in this protruding edge area, which can only absorb small forces, but significantly improves the appearance of the packaging bag.

When this edge area is heated immediately before the heat sealing of the longitudinal seam, the pressure rollers or other pressure devices arranged after the heat sealing can be made slightly wider and can thus also be used for pressing the overlapped edge area.

The closing of the packaging bags after filling is also optimized with regard to the most exact possible shape and a hygienic closure:

In principle, as is known per se, the remainder of the packaging bag protruding above the filling material is folded flat again, as in the production of the endless bag tube, the transition from the open, filled area to the flat-folded protrusion taking place to form a gable-shaped transition zone which should be as flat as possible for reasons of optics and packing space.

The flat-folded overhang area is folded several times inwards from the upper, free end, and is fixed in this position after repeated pounding inwards, which has hitherto usually been done by means of staples, hot glue or the like.

Depending on the dimensional stability of the filling material, however, the formation of the gable-shaped transition zone is problematic when the excess of the bag is folded flat above the filling zone, since this again does not result in an exact shape the previously known procedures took place, and thus no exact final bag shapes could be achieved.

According to the invention, an exact gable formation is achieved in that, in addition to the positional fixation of the longitudinal side parts by means of outer plates attached to the outside, possibly with suction cups engaging on the bag, the narrow side parts are also held by means of outer plates and suction cups, and correspondingly gable-shaped swivel plates in the gable-shaped transition area attack the narrow-sided side parts and fold them in to form the gable, in that the swivel plates can be folded inwards from a position parallel to the narrow side part about a swivel axis running parallel to the width of the bag bottom.

In order not to create any undesired wrinkles etc., but rather the exact shape desired, a suction cup can also be arranged approximately in the middle of each of the two swivel plates, which holds the corresponding area of the respective side part. When swiveling inward, the edges of the swivel plate that face upwards form the upper end edges of the gable-shaped area of the narrow side parts of the bag.

This enables an angle in the gable tip of more than 120 °, preferably even more than 140 °.

After the gable has been formed in this way, the upper end of the gable is now additionally fixed and, at the same time, the bag is hygienically closed by pulling an upper transverse seam from one to the other outer edge of the protruding part of the bag, which is now folded flat again. This upper transverse seam is also sealed by means of ultrasound, it being additionally achieved by appropriate choice of the coating materials that only the inner coatings of the bag tube, which are directed against one another, are sealed against one another, and thus in the edge area, in turn by four layers of the bag tube lie one above the other, only the two outer layers are sealed against each other, but not the two middle layers against each other, which are in contact with one another with their outer coatings.

This is achieved in that the coating arranged on the inside of the bag tube has a lower melting point or a lower temperature from which the coating becomes doughy and can stick together.

It is only sensible to glue the inside coating because this cross seam, due to the later turning of the upper edge downwards, towards the filling, and the fixing of the wrapping, is normally hardly exposed to external forces, but only one after the filling process immediately applied hygienic separation of the filling material from the environment.

Such a relatively poorly developed seal is also useful at this point because it is evidence for the consumer, who opens the bag for the first time, especially with the food it contains, that the contents of the bag have not been accessible to any other person after filling .

Another intended effect is that after opening the bag for the first time by tearing this transverse seam, not all of the paper and thus the bag in the region of this upper transverse seam is damaged, but only its inner coating. The paper itself remains intact, so that even after opening and thus tearing open this upper transverse seam, it is possible to re-close it by wrapping the prefabricated, multiple envelope in the upper area, since the paper is not completely torn.

For this purpose, the transverse seam present above the filling material is formed in a zigzag shape by the Sonotrode and / or the anvil acting as a counter-holder have such a zigzag shape. The tines point up or down in the standing bag and should be as pointed as possible, preferably with an intermediate angle of less than 100 °, preferably less than 70 °. Since the tearing takes place by pulling apart from above, a flat tearing is started from the top teeth and is only conveyed in the coating material on the inside, without tearing through the paper which acts as a carrier material.

Fixing the multiple wrapping in the same direction, especially at its edge areas, which - depending on the number of wrapping - thus comprises a multiple of four layers, is preferably done again by ultrasound, because despite the large number of paper layers available due to the adjustable Depth effect a sealing in the desired depth range is possible.

The goal is to fix the multiple wrap at the upper end of the bag by connecting the respective outer coatings of the bag tube, while the underlying transverse seam, which is arranged directly above the filling material, should only seal by means of the inner coating. To achieve this, to support the control of the ultrasound exposure with regard to the depth effect, the area above the internal sealing transverse seam can also be provided with a different outer coating and / or different inner coating than the area below, and thus the area in which this occurs inside sealing cross seam. the selective application of different coatings in the longitudinal direction of the bag tube is easily possible when the bag tube is manufactured from the material removed from the roll by appropriate control, as is a corresponding label for the bag already after the bag tube has been produced, but usually before the cutting of the individual bags is applied. This label is preferably at least partially removable and is used after opening and provisional reclosing Tracing the upper multiple fold for additional fixation.

Through selective use of different coatings, possibly also the same coating material but in different thicknesses etc., it can be achieved that the cross seam directly above the filling material only adheres or sticks with the inner coating, the overlying seals of the wrap at the upper end, however, only with the outer coatings. For this purpose, the melting temperature or dough temperature of the inner coating should be significantly higher in the lower area than that of the outer coating, while the reverse must apply in the upper area.

The use of paper for the bag with a weight of 60-80 g / m ² , which is coated on the inside with polyethylene and on the outside with polypropylene, has proven to be a particularly favorable combination.

Preferred layer thicknesses are 20 microns of polyethylene on the inside and 15-20 microns of polypropylene on the outside of the later bag tube, so-called low-density polyethylene is preferably used as the polyethylene on the inside, which then only has a layer thickness of about 15 microns . With this choice, a low paper weight of only around 60 g / m ² is also preferred.

Such a material uses ultrasound in the range of approximately 40 kHz. If the contact areas of the sonotrodes are usually narrow, almost linear, with a contact area width of 1 to 5 mm, the length of the contact areas of the sonotrodes should not exceed 150 mm. Instead of a bar-shaped configuration of the sonotrode, a narrow, zigzag-shaped design also offers advantages from this point of view.

If larger areas or lengths of the sonotrodes are required, the frequency must be reduced to about 20 kHz, in which case the maximum length of the sonotrodes may be up to about 300 mm. However, since certain minimum lengths must then be adhered to at the same time, this may lead to the use of ultrasound of different wavelengths and thus different generation systems, which additionally increases the structural complexity and in particular the control complexity.

In addition, the sonotrodes can also be cooled, e.g. liquid-cooled or cooled to room temperature by means of compressed air, whereby the control of the sealing process can be improved.

Because for the control, in particular for the energy density used, the particular ambient temperature and thus the material temperature of the bag or its coatings before the ultrasound treatment must also be taken into account. If the temperature of the sonotrodes is constant, there can therefore be no unsatisfactory processing results, as has been customary in heat sealing up to now:

Because during heat sealing, the sealing jaws are supplied with a constant current and are constantly heated. However, the sealing temperature generated by the sealing jaws in the bag material is influenced by a number of additional factors, for example the cycle time of the seals, since energy is extracted from the sealing jaw during each sealing process. If there is therefore an acceleration or deceleration of the cycle, for example a failure-related, short standstill of the sealing device, then the temperature at the sealing point is significantly different, e.g. B. higher than intended. It is the other way round when the system starts up at the start of the shift, since then the ambient temperature and thus the temperature of the paper material is still very low, while after a certain number of operating hours the time is constantly heated due to the fact that it is in use Sealing jaws the ambient temperature at the sealing areas is much higher.

The bags according to the invention are used in particular for the packaging of individual products which have a low dimensional stability, in particular of stacked individual products.

The packaging bag is not only kept open by suction cups on all four side walls, but in addition the top, open edges of the bag are held open by longitudinal and frontal retaining flaps, which partially swivel into the bag from above, and at the same time provide sliding surfaces for those to be lowered Single product stack.

As a result, the number of stacks to be introduced during a filling process can be changed in accordance with the packaging bags to be filled at a time.

Figuren 1:

Querschnittsdarstellungen durch den zu erzeugenden, endlosen Tütenschlauch,

Figuren 2:

den geschnittenen Tütenschlauch beim Versehen mit Quernähten,

Figuren 3:

die Ausformung des Bodenbereiches im Querschnitt,

Figuren 4:

die Verstärkung und Befestigung des Bodenbereiches,

Figuren 5:

das Verschließen der gefüllten Tüte und

Figur 6:

das Verschluss-Siegeln der Tüte.

In the following, the overall process is described in more detail by way of example, partly with reference to the figures. Show it

Figures 1:

Cross-sectional representations through the endless bag tube to be produced,

Figures 2:

the cut bag tube with cross seams,

Figures 3:

the shape of the floor area in cross section,

Figures 4:

the reinforcement and fastening of the floor area,

Figures 5:

closing the filled bag and

Figure 6:

sealing the bag.

The individual work situations shown in the figures are described below on the basis of the overall process at Manufacturing, filling and closing the packaging bags, described:

Endless bag tube:

First of all - according to a method known per se - a bag tube, which is endless in principle, is created from the sheet material, usually coated paper, which is usually on a roll.

For this purpose, the strip-like sheet material, hereinafter simply referred to as paper 2, is guided along just above or below a shaped plate 36 which is only about half as wide as the strip of paper 2 coming from the roll. The laterally protruding edge regions of the paper become turned over by means of corresponding guide devices, guide plates, etc., so that the shaped plate is completely covered by paper and overlaps the latter in one area in order to be able to produce a longitudinal seam 19 in this overlapped area 20 by connecting the outer edge areas of the paper strip to one another. The production of this longitudinal seam 19 is shown in FIGS. 1:

The edge areas of the paper strip not only simply overlap, but one of the edge areas is bent into a U-shape and is therefore in two layers. This two-ply area of one paper edge is overlapped by the other paper edge. In this overlapped area 20, the bag tube moving continuously perpendicular to the plane of FIG. 1 is heated and pressed at the same time by means of a stationary heated sealing jaw 23 lying in the direction of the longitudinal seam 19, so that the inner coatings 4 of the paper 2, which consist of heat-sealable plastics, are so far are heated so that they become doughy or liquid and stick together. In order to avoid damage to the visible outer coating 3 of the layer 27 of the paper 2 lying outside in this overlapped area 20 by pulling under the standing sealing jaw 23, the sealing jaw 23 is not applied directly but with the interposition of a Teflon tape 37, and the pressure regulated so that a sufficient There is heat transfer for effecting the bond, but not so great sliding friction between the outer coating of the paper 2 and the Teflon tape 37 that this coating is damaged.

The U-shaped fold of the inner paper edge at the longitudinal seam 19 serves to increase the security of the bond, since the additional paper layers provide a slight increase in the area of the longitudinal seam 19 compared to the other areas on the same side of the shaped plate 36. The pressing sealing jaw 23 is at most as wide as the U-shaped, overlapping area 20 of the longitudinal seam 19. However, the outer edge of the paper web projects slightly beyond this overlapping area 20 and forms a projecting edge area 21 around the actual longitudinal seam 19 to cover optically.

However, this protruding edge area is not glued in the prior art - since it is not in the area of the sealing jaw 23 - and is therefore loosely projecting, can thus be pulled up and damaged, and is clearly visible even with a simple twist due to the then visible inside of the paper 2 or the inner coating 4, which is usually has a different color than the outer coating 3. Although the coatings themselves are usually colorless, on the outside of the paper 2, however, the desired outer color and the printing of the packaging bag 1 are initially arranged under the outer coating 3.

In order to avoid this, the protruding edge region 21 of the outer layer 27 in the region of the longitudinal seam 19 is also glued to the underlying bag tube 7.

For this purpose, the protruding edge region 21 is first brought to a distance from the underlying paper 2 of the bag tube 7 by means of a guide wedge 38, which is stationary, as is the sealing jaw 23, and hot air is blown into this space by means of a heating fan 39, so that at least the inner coating 4 of the protruding edge area 21 and the underlying outer coating 3 of the bag tube 7 are heated to such an extent that when the two coatings are subsequently pressed against one another by means of a pressure roller 40 or the like - as shown in FIG. 1b - the protruding edge area 21 is glued.

After the molded sheet 36 has run off, an endless bag tube 7, closed in cross section, is thus available. This is also simply turned inwards by means of devices known per se on its side parts 6, i.e. from the outer edges 22 of the bag tube 7, so that the distance between the side edges 22 is reduced, and in the outer areas of the bag tube 7 the paper the E-shaped fold is four-ply, as can be seen better in FIGS.

This can also be done before the longitudinal seam 19 is produced, but then the shaped plate 36 should have a groove on its narrow longitudinal sides - dashed in FIG. 1b - for receiving the E-shaped fold-in.

Production of the individual packaging bags :

After the possibly necessary, longitudinally selective, inner and / or outer coating, labeling and cutting of the endless bag tube 7 to the desired length of the packaging bags 1, these are further transported by means of a suitable conveyor belt 41 etc. to the following processing stations.

As shown in FIG. 2, various sealing seams, which run essentially transversely, are created in order to produce a dust-tight and - depending on the coating material or surface material used - even liquid-tight lower end of the later packaging bag 1.

For this purpose - according to FIG. 2a - the K-seams 10, which run laterally obliquely to the edges of the flat-folded bag 1, are first applied.

Subsequently - according to FIG. 2b - the double-sealed K-transverse seam 9 running from one outer edge 22 to the other outer edge 22 'and running parallel to the lower end edge is sealed from one side by means of a heat-sealing jaw 23', and then - according to FIG. 2c - by means of a another heat seal jaw 23 '' from the other side of the bag. The double design of this transverse K-transverse seam 9 not only increases the security against gluing in the central area, but also means that an intermediate plate 42 is pushed in from the sides when the oblique K-seams 10 are created, so that the K- Seams 10 in each case only the two uppermost layers of paper 2 are glued to one another by means of their inner coatings 4 lying opposite one another. Sealing from both sides

The two middle layers are not glued to one another by means of their outer coating 4, in contrast to the transverse K transverse seam 9, which firmly connects all four layers in the edge region 31, and thus also the two middle layers to one another.

The K-seam 9 is not placed very close to the lower end of the bag 1, but at such a distance that the protruding fin 8 produced by the K-seam 9 has an extension in the longitudinal direction of the bag tube 7 that is approximately half corresponds to the later width of the bag. The free end of the fin 8 is finally simply sealed by means of a further sealing jaw 23 '' 'with a further transverse seam 18 at the end, whereby, however, no secure, tight closure of all layers of the flat bag tube 7 against one another is guaranteed, but a connection which is firm enough to ensure that to facilitate later handling of this fin 8.

Forming the bottom of the bag:

The packaging bags 1 created in this way are then passed through suitable handling devices, preferably by means of suction cups 28 and preferably already in the correct, vertical position, opened by the suction cups 28, 28 'engaging on the opposite side parts 6 on the outside, and moving them apart, as a result of which the packaging bag 1 merges into the open state. From the bottom 15 of the bag, the fin 8 projects downwards in the middle with a length which corresponds to approximately half the width of the bottom 15 of the bag.

At the same time, a vertically movable mechanism is inserted into the packaging bag 1 from the upper, open side, to which a multi-part bottom form stamp 11 is fastened via a scissor linkage 1. The two parts 11a, 11b of the bottom die 11 have a length corresponding to the length of the bottom longitudinal edges 16 of the bag bottom 15 (or can be extended telescopically up to this length), but together they result in a substantially smaller width than the width 5 of the bag bottom 15.

The two parts 11a, 11b are each articulated when inserted into the bag 1 at the end of a strut 43a, 43b of the scissors linkage 43, the intermediate angle 44 of which is relatively small when the bottom shaping stamp 11 is inserted into the bag to prevent the bottom shaping stamp 11 from being inserted to facilitate the bag bottom 15. This intermediate angle is then increased. in that the hydraulic cylinder arranged on the mechanics pushes apart the struts 43a, b mounted on the mechanics until the parts 11a, b of the base mold stamp attached to them have reached the outer edges of the bag interior.

The two parts 11a, 11b of the bottom die 11 have raised fold edges 13a, 13b along their outer, lower, longitudinal edges directed towards the bag bottom 15. Shortly before reaching the bag bottom 15, the parts 11a, 11b of the bottom shape stamp 11 are brought to a distance by enlarging the intermediate angle 44 so that the folded edges 13a, 13b rest on the rear sides of the bottom longitudinal edges 16 and are held in this position with the aid of the bottom shape stamp 11 including the scissors linkage 43 supporting device.

As shown in FIG. 3b, bottom molds 12a, 12b are now approximated from the underside of the bag bottom 15 against the parts 11a, 11b of the bottom die 11 and the bag bottom 15 is pressed in between. The bottom molds 12a, 12b have depressions 14a, 14b corresponding to the raised fold edges 13a, 13b, so that the longitudinal edges 16 of the bag bottom 15 in particular are given a permanent shape by this pressing process.

This is additionally supported by the fact that the bag 1 is exposed to an elevated temperature in the area of its bag bottom 15, in that before and during these processes the paper 2, or at least its outer coating 3, is correspondingly high by means of heating fans 39 ', 39' ' tempered warm air is acted upon so that at least the outer coating becomes slightly plastic.

After removing the bottom form stamp 11 and the bottom form backdrop 12, which preferably takes place after the paper 2 has partially cooled again, the bag has an exactly shaped bag bottom 15.

Stabilization of the bag bottom 15 :

This is additionally stabilized in that - as shown in FIGS. 4 - the bag 1 is held apart by the suction cups 28 attached on both sides and the fin 8 projecting downwards from the center of the bag bottom 15 by means of a suitable pivot lever 45 which can be pivoted approximately below the fin 8 is stored, is folded over until the fin 8 comes to lie parallel and in contact under one half of the bag bottom 15, so that a substantially flat contact surface of the bag is created. The longitudinal edge 32 of the free end of the fin 8 is only slightly from a bottom longitudinal edge 16 of the bag bottom 15.

In order to connect the fin 8 in this folded position to the bag bottom 15 and thereby stabilize the entire bag bottom, the folded fin 8 is welded with one half of the bag bottom by means of ultrasound, by pressing ultrasonic sealing jaws 53, 53 'against the fin 8 from below. Counterholders 17a, 17b, which are inserted into the inside of the bag 1 and serve as counterholders, are fastened to an analog scissor linkage 43a, 43b like the bottom form stamp 11a, 11b. These counterholders 17a, 17b can therefore be inserted into the open bag 1 from above in a relatively approximated state, and are only moved apart by increasing the intermediate angle between the scissor arms 43a, 43b when they reach the bottom of the bag so that they are on the inside of the bag Bottom 15 and the inside of the bottom longitudinal edges 16 of the bag 1 and apply the necessary counterforce for the ultrasonic sealing jaws 53, 53 '.

For this purpose, the counterholders 17a, 17b also overlap somewhat in the moved-apart state, the one counterholder 17b having an underside 46 lying directly against the bag bottom 15, which corresponds in cross-sectional representation to at least the dimensions of the folded fin 8.

The ultrasonic sealing jaws 53, 53 'are guided against the bag 1 with approximately 30 to 40 kg of pressing force. The ultrasonic sealing jaws 53 attach to the folded fin 8 on the side edges thereof, in which the fin has four layers due to the lateral turning inwards. Using ultrasound, it is nevertheless possible to seal at least the lowest position of the fin 8 with the base 15, which is closest to the base 15.

In contrast, the ultrasonic sealing jaw 53 'seals part of the longitudinal edge 32 at the free end of the fin 8, and only in its central region, in which the fin 8 is formed only in two layers, so that the sealing there is to be carried out by means of ultrasound with other setting parameters.

Filling the bags :

As can be seen in FIG. 5 a, the packaging bag 1 is thereby suction cups 28 resting against the side walls kept open, and additionally by longitudinal and frontal retaining flaps 29, 30, which are curved in cross section, and can be pivoted about a pivot axis outside the packaging bag 1 in the vicinity of its upper, free edge so that in the pivoted-in state, the retaining flap extends over the corresponding one The upper edge of the open packaging bag 1 extends slightly into the inside of the bag, thereby protecting the free edge of the bag from damage. At the same time, through the curved outer surface of the holding flaps 29, 30, which additionally point into the interior of the packaging bag 1, slightly misdirected fillings are still guided into the interior of the bag 1.

Closing the filled bag:

The bags 1 are far from being filled up to the upper, open edge, since the protrusion of the bag 1 over the filling serves to close the bag 1. For this purpose, the supernatant has been brought back into the flat-folded state, with the side parts 6 folded inwards, as when the bag tube 7 was manufactured, so that a gable 54 must be created as a transition between the filled area and the protruding area.

This is done - as can be seen in FIG. 5c - by bringing pivot plates 25 close and parallel to the side parts 6, the upper end of which has the intended gable shape and which is parallel to the bag bottom 15, just above the filling on the side parts 6 of the packaging bag 1 extending pivot axis are pivotable so that their upper, gable-shaped end moves into the interior of the bag and thereby folds the side part 6 in a gable shape. In order to avoid warping, folding and similar undesirable shaping of the side parts 6, the swivel plates 25 have suction devices 26 directed against the side parts 6 in order to ensure a defined folding of these side parts. In addition, the bag can continue to be provided by further, adjacent suction cups 28 as well as stabilizing plates resting on the longitudinal outer surfaces - with or without attacking the bag Suction cups - be kept in a stable open position in the area of the filling.

This enables a very flat gable to be achieved - up to an angle of inclination of only 20 ° even in the bag's suspended sand - which saves storage space and improves stackability.

After this generation of the gable 54, sealing takes place immediately at the lower end of the folded-over projection 60 of the bag 1, by a counter-holder 59 being brought from one side and an ultrasonic sealing jaw 58 being brought to this projection 60 approximately parallel to the bag bottom 15 and against one another from the other side be pressed.

Both parts extend over the entire length of the bag 1, as a result of which the inner coatings 4 of the individual layers 27 take place, as can be seen in FIG. 5e, in that the ultrasonic sealing jaw 58 and / or the counter-holder 59 are zigzag-shaped, with tips pointing upwards and downwards are formed and / or the energy supplied and other parameters that can be set for the ultrasound sealing, such as exposure time, contact pressure, etc., are regulated so that in the middle, two-layer area of the projection 60, the two outer layers 27a, 27b, which are only present there, with their inner coatings 4 with one another are welded by means of ultrasound, but in the region of the four-layer edge regions 31 only the two outer layers 27a, 27c and 27d, 27b are in turn connected to one another by means of their inner coatings. A connection of the two middle layers 27c, 27d by means of the outer coatings 3 lying against one another does not take place and is also not desired.

Due to this relatively light, but nevertheless tight way of closing the filled bag, on the one hand, an unnoticed opening of the bag after the closing process is no longer possible, since damage to the bag is easy to notice inner coating occurs. On the other hand, the buyer of the bag can open it without severely damaging or even destroying the entire bag 1 in its upper region. Rather, only the inner coating suffers slight damage due to tearing open, so that after the first opening and removal of part of the filling, it can easily be reclosed by rolling in the upper overhang and possibly sticking over with the at least partially removable label on the bag is.

Simultaneously or immediately after the bag is closed by means of the ultrasonic sealing jaw 58, the pivoted-in swivel plates 25 are brought out of contact with the bag 1.

Subsequently, as can be seen in FIG. 6, the upper protrusion 60 is turned over several times in the same direction, and then this rolled-up upper edge 61 is fixed by again, essentially horizontally, an ultrasonic sealing jaw 58 'and a counter-holder 59' from opposite sides be brought up to the rolled up upper edge and fix it under pressure using ultrasound. Not all, but only a few, preferably only one of the outer coatings are connected to one another, but not over the entire length of the rolled edge 61, but possibly only in its lateral, outer regions.

When the sealing seams are applied above the bag filling, the sealing jaws 58 and 58 'and the counterholders 59 and 59' with the bag which has been transported further preferably move in order to simultaneously use the transport time for the sealing.

Claims (13)

Process for producing, filling and closing a packaging bag from a limitedly flexible sheet material with the following process steps: - Bottom-side closure of the flat, with its side parts (6) determining the width (5) of the bag (1) at least simply folded inwards, the bag tube (7) to form a fin (8) by means of at least one transverse seam, - opening the bag (1) and inserting a bottom form stamp (11) into the bag (1) up to the bottom of the bag (15) while positioning raised fold edges (13) of the bottom form stamp (11), at least along the bottom longitudinal edges (16), - Forming the bottom of the bag (15) by approximating a bottom shape (12) with depressions (14) corresponding to the folded edges (13), - Pressing the bag bottom (15) between the bottom form stamp (11) and bottom form link (12) and - Turning over the fin (8) and connecting the fin to the bag bottom (15) using a counter-holder (17) supporting the bag bottom (15) inside the bag (1). Method according to claim 1,
characterized in that
the surface material (2) consists at least on its inner surfaces of heat-sealable, in particular ultrasonically sealable, material. Method according to one of the preceding claims,
characterized in that
the surface material has an outer coating (3) and an inner coating (4) - based on the later bag (1) -, wherein the inner coating (4) has a lower melting point than the outer coating (3). Method according to one of the preceding claims,
characterized in that
the transverse K transverse seam (9) forming the fin (8) is supplemented by K seams (10) which rise towards the side parts (6) and the open end of the bag tube (7). Method according to one of the preceding claims,
characterized in that
the K transverse seam (9), which extends the K seam (10) and runs transversely to the bag tube (7), extends to the outer edges (22) of the flat bag tube (7) and in the side area of the bag tube (7) there is all at least four layers of the sheet material (2) firmly connected. Method according to one of the preceding claims,
characterized in that
the fin (8) near its free end is closed by an additional transverse seam (18) which extends over the entire width of the bag tube (7) and at least fixes the inner coatings (4) of the bag tube against one another and the connection of the folded-over Fin (8) on the bag bottom (15) along the substantially entire narrow edge regions (31) of the folded fin (8) and at least along part of the free longitudinal edge (32) of the folded fin (8). Method according to one of the preceding claims,
characterized in that
in the production of the bag tube (7) from the sheet material (2) in addition to the overlapped, three-layer area (20), the edge area (21) projecting on the visible outside is connected to the layer (27) of the sheet material (2) underneath and when creating the longitudinal seam (19) on the overlapped, three-layer area (20) by heating by means of heated sealing jaws protruding edge area (21) is heated by hot air immediately before the longitudinal seam (19) is created. Method according to one of the preceding claims,
characterized in that
the bottom of the bag (15) is shaped between the bottom die (11) and the bottom link (12) under elevated temperature of at least one coating (3, 4) of the surface material (2). Method according to one of the preceding claims,
characterized in that
when the bag (1) is closed, before the free upper end is folded in, an upper transverse seam (24) is arranged over the entire width of the flat-folded bag tube (7) above the filling of the bag (1) so that the transverse seam (24) only the inner coatings (4) of the sheet material (2) of the bag tube (7) are connected to one another. Method according to one of the preceding claims,
characterized in that
the transverse seam (24) is zigzag-shaped. Method according to one of the preceding claims,
characterized in that
the upper transverse seam (24) is made after the gable-shaped folding of the side parts (6) above the filling into the inside of the packaging bag (1) by means of swivel plates (25) which are approximately gabled in shape and the swivel plates (25) have at least one suction device ( 26) for sucking the surface material (2) of the side parts (6). Method according to one of the preceding claims,
characterized in that
at least the connection of the folded fin (8) to the bag bottom (15) and the creation of the upper transverse seam (24) by gluing the coatings (3, 4) of the surface material (2) to one another by means of ultrasound. Bag, in particular for carrying out the method according to one of the preceding claims,
characterized in that - The fin (8) has a free length that corresponds to half the width (5) of the bag bottom (15), - The fin (8) is closed at its free end by means of an additional sealing seam, - The fin (8) is folded parallel to the bag bottom (15) and connected to it, - The bag is sealed immediately above the filling by a transverse seam, by means of which only the inner coatings of the opposing layers of the surface material (2) of the packaging bag (1) are connected to one another.

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