EP3017940B1 - Method and a device for the production of bags from tubular bag bodies - Google Patents

Description

The invention relates to a method and an apparatus for producing sacks of tubular bag bodies, wherein the bag body preferably made of a fabric of plastic tapes or a nonwoven plastic material (eg plastic fleece) or a composite of the fabric of plastic tapes and the nonwoven plastic material or with a a plastic film connected to a network structure are produced, wherein the material optionally at least one side with at least one plastic layer and / or at least one plastic film, eg an OPP film is coated. The bag bodies are transported on a transport device lying flat transversely to its longitudinal extent at a transport speed in a transport direction, wherein the bag body undergo processing stations during their transport, with which at least one end portion of each bag body formed into a cross bottom and optionally a cover sheet is applied to the cross bottom.

Chest bags, also called cross-bottom bags, are sacks of parallelepiped shape, which are manufactured in bag making machines by providing tubular bag bodies whose open end portions are folded into cross bottoms. The bag bodies are guided lying flat through the clothing plant, so that two layers of the tubular bag body abut each other. For bottom formation, the two layers are separated at the end portions of the tubular bag body, and one of the two layers is folded over as a side flap by 180 ° to itself, creating an open bottom, in which the other layer forms a second side flap. By folding a layer at the end of the tubular bag body arises at the front and rear of this end portion each have a triangular corner impact. This process is called in the jargon also "Aufziehen". In a further processing sequence, valve sheets can be inserted (for the production of "box valve sacks" which can be filled with filler through the valve) and the final bottom configuration is made by overlapping the bottom side flaps. The overlapping bottom side flaps are glued together or thermally welded depending on the material of the bag body. Alternatively or additionally, bottom cover sheets can be placed on the overlapped bottom side flaps and glued or welded to them. Such a Sackkonfektionsanlage is in the patent AT 408 427 B described.

The throughput of sack confectioning equipment is significantly dependent on the transport speed at which the hose sections to be assembled are transported through the clothing plant. As a disadvantage of the patent AT 408 427 B known Sackkonfektionsanlage has the cyclic operation of this system has been found that limits the throughput of processed to bag bodies. The time required for cyclic mounting of the floors, including the required fixation of the raised floors, may even be an upper limit to the performance of the entire sack making apparatus.

This disadvantage was caused by in the EP 2 441 574 B1 has been overcome disclosed apparatus for forming open trays on bag bodies, which allows a continuous conveying of the bag body, which led to an increase in transport speed and productivity.

The transport speed of bag bodies in Sackkonfektionieranlagen could continue through in the EP 2 711 166 A1 described invention be increased, with which the clock frequency of a workpiece holder in the transfer area of bag bodies from the longitudinal transport was increased to the transverse transport.

Meanwhile, with the increase of the transport speed to the limits of the performance of along the transport path of the bag body arranged means for forming the cross bottoms, in particular hot air welding devices for attaching bottom cover sheets and / or valves to the bag bodies, encountered. Therefore, an increase in the throughput of Sackkonfektionieranlagen can not be achieved by a further increase in the transport speed of the bag body.

In clothing plants for box bags or box valve bags according to the prior art tubular bag bodies are fed transversely to their longitudinal extent of a continuously moving transport device and go through their transport different processing stations, such as a bottom opening device. Such a clothing factory is in Fig. 8 shown schematically. When transporting the bag body in the transverse direction of the repeat (x), which is the distance between the front longitudinal edges or the rear longitudinal edges of two successive bag body (10), usually set fixed and remains constant even when processing differently wide (b) tubular bag bodies , Thus, the throughput of bag bodies by the Sackkonfektionieranlage essentially of the transport speed (V) the transported bag body and the rapport dependent. Especially with bag bodies of small width (b) resulting from the fixed repeat (x) relatively large distances (y) between the bag bodies (10), which prevent the transport potential of the Sackkonfektionieranlagen is fully utilized.

A further disadvantage of the fixed set repeat is that hot air welders needed for attaching the ground cover sheets run empty between the successive bag bodies, whereby considerable energy in the form of hot air is released unused to the environment as a shutdown and Restarting the hot air welding devices between successive sacks for technical process reasons is not possible.

DE1216196B discloses that the realization of the obvious idea, after the removal of the workpieces from the longitudinal conveying area to reduce the workpiece speed, which would also reduce the distance of the workpieces from each other, apart from the practice due to the complexity and increase in price of the device. It will be in DE1216196B thus discouraged explicitly from the realization of the discussed idea. It is therefore an object of the present invention to increase the throughput of bag bodies in Sackkonfektionieranlagen without increasing the transport speed of the bag body.

This object is achieved by an apparatus and a method for producing sacks of tubular bag bodies with the features of claims 1 and 11, respectively.

Advantageous embodiments of the invention are set forth in the subclaims and the description below.

The inventive device and the inventive method for the production of bags from tubular bag bodies are particularly suitable for processing bag bodies, consisting of a fabric of plastic tapes or a nonwoven plastic material (eg plastic fleece) or a composite of the fabric of plastic tapes and the nonwoven plastic material or a plastic film connected to a network structure, wherein the material is optionally at least one side with at least one plastic layer and / or at least one plastic film, eg an OPP film is coated.

The bag bodies are transported lying flat transverse to their longitudinal extent at a transport speed in a transport direction, wherein formed on the bag bodies during their transport at least one end portion to a cross bottom and optionally a cover sheet is applied to the cross bottom.

To be transported bag body are moved by at least one transfer device in relation to transported at transport speed bag body by a feed distance in the transport direction and then moved at the transport speed, wherein the movement of the bag body on the feed path at least partially takes place with a transfer speed which is greater than the transport speed. By this measure, the length of the repeat is adjusted and can be adjusted to a predefined distance between adjacent bag bodies by the feed distance is calculated and controlled in dependence on the width of the bag body so that the predefined distance between successive bag bodies or between the cover sheets sequentially Sack body results. So that the device according to the invention can be operated automatically, the width of the bag body is detected by a sensor.

For a gentle treatment of the bag body and for an exact recording of the bag body and transfer to the transport device, the speed with which bag body can be moved on the feed line, be controlled according to a speed profile. The speed profile includes accelerating to the transfer speed and, after a length of time dependent on the length of the feed distance, braking to the transport speed.

With the device according to the invention, the bag making can be further improved and automated even higher, if based on the detected bag width and the predefined distance of successive bag body, the cover sheet nominal position and the desired length of the cover sheets and optionally calculates the desired valve leaf position of valve leaves and using this information cover sheets are cut to the desired length and applied to the bag body when they have reached the cover sheet set position, and optionally the valve sheets are applied to the bag body when they have reached the desired valve leaf position ,

With the device according to the invention and the method according to the invention, it is possible to select the feed path such that a very small predefined distance between successive bag bodies results, which is preferably no greater than 5 cm. Adjacent bags can also be arranged flush with each other.

An even better utilization of processing stations, such as a hot air welding station is achieved when the feed distance is chosen so that successive bag bodies overlap, preferably the overlap width of the simple or twice the height of the triangular corner impact, which results when turning the bottom side flaps. In the latter case, at least one of the successive bag bodies, a longitudinal section facing the other bag body, which has a width which corresponds to the height of the corner impact, is folded over.

For reliable handling, the transfer device preferably has holding means for gripping, holding and releasing the bag body, wherein the holding means can be designed as mechanical grippers and / or vacuum cups. A controller controls the times at which the holding means grasp and release the bag bodies. If at least two holding means are provided which are movable independently of one another, it is possible by means of suitable control to align misaligned bag bodies by different movements of the holding means. Misalignments may e.g. caused when cutting the bag body.

Fig. 1

zeigt eine schematische Darstellung einer Sackkonfektionieranlage gemäß den Prinzipien der Erfindung.

Fig. 2

zeigt eine perspektivische Darstellung einer Sackkonfektionieranlage gemäß einer Ausführungsform der Erfindung.

Fig. 3

bis Fig. 6 zeigen Draufsichten auf Sackkörper während ihres Transports auf der Transportvorrichtung, die die Abstände zwischen aufeinanderfolgenden Sackkörpern gemäß der Erfindung illustrieren.

Fig. 7

zeigt eine schematische Darstellung einer weiteren Ausführungsform einer Sackkonfektionieranlage gemäß den Prinzipien der Erfindung.

Fig. 8

zeigt schematisch eine Transportvorrichtung einer Sackkonfektionieranlage gemäß dem Stand der Technik.

The invention will now be described in more detail by means of embodiments with reference to the drawings.

Fig. 1

shows a schematic representation of a Sackkonfektionieranlage according to the principles of the invention.

Fig. 2

shows a perspective view of a Sackkonfektionieranlage according to an embodiment of the invention.

Fig. 3

to Fig. 6 show plan views of bag bodies during their transport on the transport device, illustrating the distances between successive bag bodies according to the invention.

Fig. 7

shows a schematic representation of another embodiment of a Sackkonfektionieranlage according to the principles of the invention.

Fig. 8

schematically shows a transport device of a Sackkonfiereieranlage according to the prior art.

With reference to Fig. 1 and Fig. 2 The principle of the device 1 according to the invention and of the method according to the invention for producing sacks made of tubular bag bodies 10 will now be explained and described with reference to an exemplary embodiment. The device 1 comprises a transport device 2, which transports the bag body 10 lying flat transversely to its longitudinal extension L at a transport speed V in a transport direction T. The bag bodies have a front side edge 11 and a rear side edge 12, between which the width b is measured. Guide rails 3 hold the bag body 10 in the correct position on the Transport device firmly. The bag bodies 10 are made of a stretched plastic tape fabric or a nonwoven plastic material (eg, nonwoven fabric) or a composite of the fabric of plastic tape and the nonwoven plastic material or a plastic film bonded to a net structure, and are preferably provided with a coating of a polymer , Composites may also include plastic films, paper sheets or metal foils. The coating preferably has a layer of an OPP film, furthermore printing layers, etc.

In the embodiment of Fig. 2 a hose 10a is supplied from a storage device, not shown, or an inline hose-forming machine to a cross-cutting device 8, which cuts tubular bag bodies 10 from the hose 10a and feeds them to the transfer device 4 described in detail below.

During their transport on the transport device 2, the bag body 10 passes through processing stations with which at least one end portion 13 of each bag body 10 is formed into a cross bottom and a cover sheet 19 is applied to the cross bottom. In the described embodiment, the processing stations described below are formed. In other embodiments of the invention, however, not all of these processing stations are realized, or other processing stations (quality inspection, printing equipment, etc.) may be provided.

The processing stations are in Fig. 1 for the sake of clarity only symbolically represented by arrows. A folding station 30 serves to fold the end portions 13 of the bag body 10 from the flat state about the guide rails 3 upwards. A bottom opening station 40 is used to pull the two folded-up layers of the end portions 13 of the bag body 10 from each other and fold in opposite directions by 90 °, creating an open bottom 17 is formed, which has two side flaps 15, 16, of which a side flap 16 to 180 ° is folded back onto the wall of the bag body 10. By folding over the side flaps 15, 16 is formed at the front and rear of the open bottom 17 each have a triangular Eckeinschlag 14. In a valve sheet insertion station 50, a valve sheet 18 is placed on the open bottom 17 of the bag body 10 and optionally by gluing or thermal welding fixed. Thereafter, in a bottom forming station 60, the final cross-bottom configuration is made by wrapping the bottom side flaps 15, 16, while the triangular envelopes 14 are reduced in size at the front and rear bottom end portions, but are retained in their triangular shape. Since the side flaps 15, 16 are folded over at mutually parallel folding edges, have the triangular envelopes in the shape of an isosceles triangle whose Hypotenuse runs between endpoints of the folded edges. The embossed bottom side flaps 15, 16 are glued together depending on the material of the bag body or thermally welded when they overlap each other. However, there are also embodiments of bags in which the bottom side flaps 15, 16 do not overlap each other. In the illustrated embodiment, a cover sheet applicator station 70 for applying a bottom cover sheet 19 to the embossed bottom side flaps 15, 16 and a hot air welding station 80 for fixing the bottom cover sheet 19 on the embossed bottom side flaps 15, 16 are also provided. The topsheet application station 70 and the welding station 80 may be integrated with one another. As an alternative to the welding station 80, a gluing station can also be provided.

According to the invention, the device 1 has a transfer device 4, the bag body 10 are supplied either transversely or longitudinally. The transfer device 4 transfers the supplied bag body 10 in transverse arrangement to the transport device 2 by means of a movement in the transport direction T. According to the invention, the transfer device 4 moves the bag body 10 to be transported with respect to transporting speed V conveyed bag body by a feed distance .DELTA.y in the transport direction T and then passes them on the transport device 2, wherein the transfer device 4, the bag body 10 moves in the transport direction T at least partially with a transfer speed U, which is greater than the transport speed V. So while the bag body 10 in the supply to the transfer device 4 a distance y1 from each other and with the Transport speed T move in the transport direction, they have after the transfer to the transport device 2 a reduced distance y2 from each other, which comes about by the movement of the feed distance .DELTA.y. The feed distance Δy can thus be calculated as follows: $$\mathrm{Feed\; distance\; \Delta y}=\mathrm{Sackk}\ddot{\mathrm{O}}\mathrm{distance\; y}\mathrm{1}-\mathrm{Sackk}\ddot{\mathrm{O}}\mathrm{<figure-callout\; id="2"\; label="distance\; y"\; filenames="imgf0005.png"\; state="\{\{state\}\}">distance\; y</figure-callout>}\mathrm{2}$$

By reducing the distance of adjacent bag bodies from y1 to y2 between the tubular bag bodies during transport, the original length of the repeat x1 is shortened by the feed distance Δy to the repeat length x2. Thus, the throughput of bag bodies 10 can be increased by the device 1 at a constant transport speed T.

As in Fig. 2 , illustrated, the transfer device 4 holding means 4b for gripping, holding and releasing the bag body have. In this embodiment, the Holding means 4b formed as a mechanical gripper, which are fixed to belt pulleys 4c, 4d endless belt 4a. One of the pulleys 4c is driven by a drive 7 which is (automatically) controlled by a controller 6 which can also drive the holding means 4b. As an alternative to grippers, the holding means 4b may also be designed as vacuum cups. By means of the controller 6, the feed distance .DELTA.y can be calculated and changed. Further, the controller 6 can control the speed of the drive 7 and controls the timings at which the holding means 4b grip and release the bag bodies 10.

Since, according to the invention, the spacings y1, y2 between the bag bodies 10 and the bottom cover sheets 19 are varied, the processing stations 30, 40, 50, 60, 70, 80 provided in the apparatus 1 are also individual drives controlled by the control 6, for example. Switches and actuators equipped to respond to the variable bag distances. For reasons of clarity, the connection of the controller 6 with the transfer device 4 and the processing stations 30, 40, 50, 60, 70, 80 in the FIGS. 1 and 2 not shown. This connection is either point-to-point (serial or parallel), or a network connection.

The controller 6 contains a computer, with which the feed distance Δy can be calculated as a function of the width (b) of the bag body 10 such that a predefined distance y2 between successive bag bodies 10, 10 or between the cover sheets of successive bag bodies results (distance y3, please refer Fig. 1 ). The controller 6 controls the transfer device 4 in accordance with the calculated feed distance .DELTA.y.

For automatic operation of the device 1 according to the invention, a sensor 5 for detecting the width b of the bag body 10 is provided. The sensor 5 sends the detected width b to the controller 6. The sensor 5 may be camera-supported, for example, or detect the width b by means of light barriers.

In contrast to the prior art, in which the repeat is kept constant, according to the invention, the feed distance .DELTA.y is varied as a function of the bag body width b and thus changes the length of the repeat. The smaller the bag body width b, the greater the feed distance Δy, by which the bag body is advanced. The distance y2 between the bag bodies 10 can thus be kept constant even with different bag body widths b.

For a gentle handling of the bag bodies and an exact picking up and transfer, the controller 6 controls the speed with which the transfer device 4 moves the bag bodies in the transporting direction T according to a speed profile. This speed profile includes the acceleration of the recorded bag body, which are supplied to the transfer device 4 at a speed lying between 0 and the transport speed V, to the transfer speed U and after a dependent of the length of the feed distance .DELTA.y the time to decelerate to the transport speed V. Furthermore the controller 6 based on the detected bag width b and the predefined distance y2 successive bag body calculate the target position and target length of the cover sheet 19 and optionally the desired position of a valve sheet 18 and based on this information, the cover sheet application station 70 so that they a cover sheet 19 is cut according to the desired length and applied to the bag body 10 when it has reached the desired position. Similarly, the controller 6 controls the valve sheet insertion station 50 so that it applies a valve sheet 18 to the bag body 10 when it has reached the desired position. It should be noted that the length of the cover sheets mathematically results from the sack thickness determining measure by which the bottom side flaps 15, 16 are taken, since this measure the length of the fold edges, thus the length of the crossbeam and thus the length of the cover sheet 19th pretends.

By means of the transfer device 4 according to the invention, it is also possible to react to variations in width of the supplied bag bodies 10, and consequently to increase the accuracy at the following processing stations and thus to optimize the quality of the bags.

Due to the smaller distance between the bag bodies 10, the efficiency of a hot-air welding device 80 for fixing the bottom cover sheets 19 is increased, since the idling and the energy loss are minimized by unused emitted heat.

In many applications, the feed distance Δy is selected so that a predefined distance y2 between successive bag bodies between 0 (ie the bag body are flush, see Fig. 3 ) and 5 cm (see Fig. 4 ). The smaller the distance of the bag body from each other, the shorter the time in which, for example, the hot air welding station 80 gives off its thermal energy unused to the environment. In the in Fig. 5 illustrated embodiment, this distance is further shortened by adjacent bag body 10, 10 are arranged overlapping in the amount of height h of the triangular envelopes. In mathematical terms, this results in a distance of -h between adjacent bag bodies. In order to bring the distance between the cover sheets 19 adjacent bag body 10, 10 to 0, that is to arrange them flush, can in Extreme case (see Fig. 6 ) the overlap width of adjacent bag bodies 10, 10 can be selected as twice the height h of the triangular corner impact, resulting in a distance of -2h. For practical feasibility, however, it is necessary to fold at least one of the successive bag body a the other bag body facing longitudinal portion which has a width h.

It should be noted, however, that the extremely reduced distances between adjacent bag bodies 10, 10, as in Fig. 5 and Fig. 6 shown, are not suitable for each subsequent processing station. For example, if the bag body 10 from the transfer station 4 in Fig. 1 even at the transfer station are pushed together so far that they overlap, folding the end portions 13 upwards at the folding station 30 and the opening of the end portions 13 at the bottom opening station 40 would not be possible. On the other hand, extremely close distances between the adjacent bag bodies also have the advantages described above. The present invention therefore also provides that the distances between adjacent bag bodies 10, 10 are reduced in several stages by arranging a plurality of transfer devices 4 according to the invention along the transport device 2. For example, after the bottom opening station 40, a second transfer station 4 can be arranged with which the distance y2 between adjacent bag bodies 10, 10 is reduced to -h. In Fig. 7 is schematically illustrated an embodiment of the device according to the invention for the production of sacks of tubular bag bodies, those of the Fig. 1 corresponds, with the difference that in the embodiment of Fig. 7 the second transfer station 4 is arranged directly in front of the cover sheet applying station 70, whereby adjacent bag bodies 10, 10 can even be pushed together to the distance y2 = -2h. Alternatively, the distance may also be reduced stepwise with a second transfer station to the bottom opening station 40 and a third transfer station 4 directly in front of the cover sheet application station 70.

Furthermore, it is also possible for only one transfer station, which is located directly after the bottom opening station 40 or farther behind along the transport device, to reduce the distances between the adjacent bag bodies. This means that the floor opening station 40 has "more time" to open the floors while optimally utilizing the thermal energy of the welding station 80.

The fact that the distances between the bag bodies or the bottom cover sheets are varied, and the processing stations such as floor openers, valve loaders and

Cover sheet applicators are equipped with individual drives to respond to the variable bag distances.

Claims (17)

1. A device (1) for producing bags from tubular bag bodies (10), wherein the bag bodies are preferably made from a fabric of plastic strips or a nonwoven plastic material (e.g., plastic nonwoven fabric) or a composite of the fabric made of plastic strips and the nonwoven plastic material or a plastic film connected by a web structure, wherein the material is optionally coated at least on one side by a plastic layer and/or at least one plastic film, e.g., an OPP film,
   having at least one transport device (2), which transports the bag bodies in a flat manner transversely to the longitudinal extent (L) thereof at a transport rate (V) in a transporting direction (T), wherein the bag bodies, while being transported, pass through processing stations (30, 40, 50, 60, 70, 80), by way of which at least one end region (13) of each bag body is formed into a cross bottom and optionally a cover sheet (19) is applied to the cross bottom,
   characterized by at least one transfer device (4), which moves the bag bodies (10) to be transported by the transport device, with respect to bag bodies conveyed at a transport rate (V), by a feeding distance (Δy) in the transporting direction (T) and then transfers them to the transport device (2), wherein the transfer device (4) moves the bag bodies in the transporting direction (T) at least in some sections at a transfer rate (U), which is higher than the transport rate (V).
2. A device according to claim 1, characterized in that the transfer device (4) has holding means (4b) for grasping, holding and releasing the bag bodies, wherein the holding means preferably comprise mechanical graspers and/or vacuum suction means.
3. A device according to claim 1 or 2, characterized by a controller (6), which calculates the feeding distance (Δy) as a function of the width (b) of the bag bodies such that there is produced a predefined distance (y2, y3) between successive bag bodies or between the cover sheets (19) of successive bag bodies (10), and which controls the transfer device (4) according to the calculated feeding distance (Δy).
4. A device according to claim 3, characterized by a sensor (5) for detecting the width (b) of the bag bodies, which transmits the detected width to the controller (6).
5. A device according to the claims 3 and 4 in connection with claim 2, characterized in that the controller (6) controls the points of time at which the holding means (4b) grasp and release the bag bodies.
6. A device according to any of claims 3 to 5, characterized in that the controller (6) controls the rate, at which the transfer device (4) moves the bag bodies in the transporting direction (T), according to a rate profile, which comprises accelerating to the transfer rate (U) and, after a period of time as a function of the length of the feeding distance (Δy), decelerating to the transport rate (V).
7. A device according to any of claims 4 to 6, characterized in that the controller (6), on the basis of the detected bag width (b) and the predefined distance (y2) of successive bag bodies, calculates the desired position of the cover sheet and the desired length of the cover sheet (19) as well as optionally the desired position of the valve sheet of a valve sheet (18) and controls, on the basis of this information, a processing station for cover sheet applying (70) such that it cuts a cover sheet (19) according to the desired length and applies it to the bag body, if it has reached the desired position of the cover sheet, and optionally a processing station for valve sheet inserting (50) such that it applies a valve sheet (18) to the bag body, if it has reached the desired position of the valve sheet.
8. A device according to any of the preceding claims, characterized in that the feeding distance (Δy) is selected such that there is produced a predefined distance (y2) of between 0 and 5 cm between successive bag bodies.
9. A device according to any of claims 1 to 7, characterized in that the feeding distance (Δy) is selected such that successive bag bodies overlap one another, wherein the overlapping width preferably corresponds to once or twice the height (h) of the triangular corner fold (14), which is produced when the bottom side flaps (15, 16) are folded over, wherein in the latter case, at least in one of the successive bag bodies, a longitudinal portion (10b) facing the other bag body, which has a width corresponding to the height (h) of the corner fold, is folder over.
10. A device according to any of claims 2 to 9, characterized in that there are provided at least two holding means (4b), which may be moved independently from one another.
11. A method for producing bags from tubular bag bodies (10), wherein the bag bodies are preferably made from a fabric of plastic strips or a nonwoven plastic material (e.g., plastic nonwoven fabric) or a composite of the fabric made of plastic strips and the nonwoven plastic material or a plastic film connected by a web structure, wherein the material is optionally coated at least on one side by a plastic layer and/or at least one plastic film, e.g., an OPP film,
    wherein the bag bodies (10) are transported in a flat manner transversely to the longitudinal extent (L) thereof at a transport rate (V) in a transporting direction (T), wherein in the bag bodies, while being transported, at least one end region (13) is formed into a cross bottom and optionally a cover sheet (19) is applied to the cross bottom,
    characterized in that the bag bodies (10) to be transported are moved, with respect to bag bodies conveyed at a transport rate (V), by a feeding distance (Δy) in the transporting direction (T) and then at a transport rate (V), wherein the movement of the bag bodies on the feeding distance (Δy) is carried out at least in some sections at a transfer rate (U), which is higher than the transfer rate (V).
12. A method according to claim 11, characterized in that the feeding distance (Δy) is calculated as a function of the width (b) of the bag bodies such that there is produced a predefined distance (y2, y3) between successive bag bodies (10) or between the cover sheets (19) of successive bag bodies and such that the movement of the bag bodies is controlled according to the calculated feeding distance (Δy).
13. A method according to claim 12, characterized in that the width (b) of the bag bodies is detected using a sensor (5).
14. A method according to claim 11 to 13, characterized in that the rate, at which the bag bodies are moved on the feeding distance (Δy), is controlled according to a rate profile, which comprises accelerating to the transfer rate (U) and, after a period of time as a function of the length of the feeding distance (Δy), decelerating to the transport rate (V).
15. A method according to claim 13 or 14, characterized in that, by way of the detected bag width (b) and the predefined distance (y2) of successive bag bodies, the desired position of the cover sheet and the desired length of the cover sheets (19) as well as optionally the desired position of the valve sheet of valve sheets (18) are calculated and that, by way of this information, cover sheets (19) are cut according to the desired length and then applied to the bag bodies (10), if they have reached the desired position of the cover sheet, and optionally the valve sheets (18) are applied to the bag bodies, if they have reached the desired position of the valve sheet.
16. A method according to any of claims 11 to 15, characterized in that the feeding distance (Δy) is selected such that there is produced a predefined distance (y2) of between 0 and 5 cm between successive bag bodies.
17. A method according to any of claims 11 to 15, characterized in that the feeding distance (Δy) is selected such that the successive bag bodies overlap one another, wherein the overlapping width preferably corresponds to once or twice the height (h) of the triangular corner fold (14), which is produced when the body side flaps (15, 16) are folded over, wherein in the latter case, at least in one of the successive bag bodies, a longitudinal portion (10b) facing the other bag body, which has a width corresponding to the height (h) of the corner fold, is folded over.

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