HK1024453B - Method and apparatus for producing foil bags - Google Patents

Description

Method and apparatus for producing foil lined bags

Technical Field

The present invention relates to a method of producing foil-lined bags, in which method two foil sheets are supplied for forming the side walls of the foil-lined bag and a bottom foil is supplied for forming the bottom of the foil-lined bag, and the foil sheets are joined to each other, and to an apparatus for carrying out the method.

Background

Foil-lined pouches are used to receive filling materials, such as beverages. The foil-lined pouch comprises, for example, two side foils with opposite edges sealed to each other. The bottom foil, which in the folded-open state constitutes an upstanding base and forms spaces between the foils for filling material, is sealed between the respective 3 rd edges. After the filling operation, the edges of the 4 th side are also sealed to each other.

To produce such foil bags, the side and bottom foils are continuously wound from respective supply rolls on an automated processing line, stacked on top of each other in the correct order, and then sealed to each other as described above. The resulting array of foil-lined pouches is cut into individual foil-lined pouches along the seal.

In order to ensure that the foil-lined pouch is stable, it must be ensured that the side foils also engage each other in the bottom foil area. For this purpose, corresponding recesses have to be provided in the bottom foil to ensure that the side edges of the side foils also engage each other in the region of the bottom foil.

Due to failure, notch defects, misalignment or no notches at all are easily produced. Since the bottom foil is stopped between the two side foils and is thus not visible when the foil-lined pouch is in an unfilled state, it is very laborious to check the bottom foil with the naked eye for corresponding recesses, which slows down or interrupts the subsequent processing steps.

Disclosure of Invention

It is an object of the present invention to provide a method and an apparatus for producing foil-lined bags, which can reliably check the production of the respective recess.

This object is achieved by the method features and the apparatus features of the invention. The invention provides a method for producing foil lined bags comprising the steps of: a) supplying two sheets of foil forming the side walls of the foil-lined bag; b) supplying a base foil, wherein at least punched holes are punched in the base foil during the supplying, the punched holes being spaced apart in a longitudinal direction of the base foil by a distance equal to a width of the foil liner bag, and the base foil is folded along a center line of the base foil extending parallel to the longitudinal direction of the base foil, the punched holes being arranged substantially symmetrically to the center line, and wherein the punched holes are measured in step b) to determine whether or not the punched holes are generated; c) stacking the 1 st side foil, the folded bottom foil and the 2 nd side foil on each other; d) joining the series of layers at the future side edges of the foil-lined pouch such that when the bottom foil is positioned in position between the side foils, the side edges are only directly connected to each other by the punched hole; and e) cutting the connected series of foil layers such that the side connections are separated between the two foil bags, respectively.

The present invention provides a foil liner bag manufacturing apparatus comprising 1 st and 2 nd supply means for supplying side foils to be used as side walls of a foil liner bag, at least one 3 rd supply means for supplying a foil material for a bottom foil of the foil liner bag, a punching means for punching a punching hole on the bottom foil which is arranged symmetrically with respect to a center line of the bottom foil, a folding means for folding the bottom foil, 1 st measuring means for detecting the punching hole, a connecting means for connecting the side foils and the bottom foil, and a cutting means for cutting the connected foil along the connecting region.

In the feeding step, at least small holes are punched in the base foil, the small holes being spaced apart in the longitudinal direction by an interval corresponding to the width of the foil liner bag. The apertures are arranged substantially symmetrically to the centre line of the base foil in the longitudinal direction. The bottom foil is folded along said centre line. The stamping process and the folding process may also be interchanged. In the feeding process, a measuring process is carried out after the punching process to judge whether the punching hole is punched out. The side foils and the folded bottom foil should be placed one on top of the other and joined at the future side edges of the foil-lined pouch so that the side edges are only directly joined to each other through punched holes punched out when the bottom foil is in place between the side foils. Finally, the connected row of foil bags is cut such that the side edge connecting regions are each cut between two foil bags.

In the method according to the invention, it is therefore already checked before the introduction of the base foil whether the punched hole is present or not, whether the introduction position is correct or not and whether the distance is correct or not.

The results of the process measurements can be used in subsequent parts of the process, for example, for sounding or optical signals to the operator or for stopping the foil lined bag manufacturing apparatus. As the punched holes have been inspected before the bottom foil is introduced in the middle of the side foil, no reject foil bags are produced which can be rejected afterwards. In this way, the method according to the invention can improve reliability and avoid time loss due to failures.

In the method according to the invention, the stamping process may be performed before the folding process of the bottom foil. For example, the detection of the presence of the punched hole can be performed individually and accurately for all punched holes arranged edge-to-edge in a direction perpendicular to the longitudinal direction of the base foil. However, the folding process may also be performed before the punching process. The punching process and the punched hole measuring process can be performed efficiently with a minimum number of punching and measuring devices.

The foils may be bonded to each other along the future edges. Although the sealing or welding of the edges is simple and reliable.

It is possible to measure whether the punched hole is already made, for example, by means of a corresponding contact sensor. But preferably an optical measuring device is provided. The optical measurement can ensure a highly reliable non-contact measurement operation.

Another advantageous development is the use of a proximity switch which can be used in the case of foil containing metal and which does not absorb much dust and moisture.

The punching holes are symmetrically arranged beside the central line of the bottom foil of the folded bottom foil. Here, a single punched hole may be provided in a direction perpendicular to the longitudinal direction of the bottom foil, which single punched hole is also folded at the same time as the bottom foil is folded. However, providing two punched holes in a direction perpendicular to the longitudinal direction of the bottom foil and overlapping the two punched holes in the folding process, respectively, may increase the reliability of the production process and the stability of the foil lined pouch.

An advantageous development of the method is that a measurement is carried out before the foil is connected to determine whether or not the base foil is supplied. In this way, a malfunction of the bottom foil supply machine can be easily detected and the side foils are prevented from engaging each other when the bottom foil has not yet reached its intermediate position. In addition, a broken foil or an end of a foil can also be judged in this way.

Finally, sensors may also be employed to detect when a fault occurs between the sensor and a processing point disposed downstream thereof. The sign of detecting such a fault is that the signal state of the sensor does not change.

It is also most advantageous to perform the measurement optically, which can be detected without contact or by means of a proximity switch. In a simple development of the method according to the invention, the measurement of the punched hole to detect the presence of the punched hole and the measurement of the foil to detect the supply of the base foil are carried out by means of a combined measuring device.

The method according to the invention can be carried out efficiently when two supplied side foils each have a width corresponding to the extended width of the plurality of foil bags and a corresponding number of bottom foils are supplied. In this way a plurality of foil-lined bags can be produced side-by-side and the individual components, such as the connecting means or the cutting means for cutting the foil into individual base foils, need only be provided once.

The inventive device for producing foil bags for carrying out the method according to the invention comprises a punching device for punching holes symmetrically arranged beside the centre line of the base foil in the base foil, and a measuring device for detecting the punching holes. Preferably, a 2 nd measuring device is provided for detecting the presence of the bottom foil.

An advantageous embodiment is constructed in that a light barrier is included as a measuring point. The signal of the light barrier is easy to read and can be used to generate an alarm signal directly or to switch off the device.

A further advantageous embodiment is constructed in that a proximity switch is included as a measuring point. Such proximity switches are less absorbent to dust and moisture and can be used specifically in the case of metal containing foils.

Drawings

An embodiment according to the invention and a method according to the invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a foil lined bag production facility;

FIG. 2 shows the base foil before the sealing process;

FIG. 3 shows the sealed side and bottom foil prior to the cutting process;

FIG. 4 is a perspective view of a completed foil-lined bag;

FIG. 5 is a side view of a completed foil-lined bag; while

Fig. 6a and 6b are cross-sectional views taken along the lines I-I and II-II of fig. 5, respectively.

Detailed Description

Fig. 4 shows a completed foil-lined bag. And 10 denotes a welding seal line (hatched portion) that connects the side foils to each other at the side edges. And 16, the area (represented by the x sign) where the bottom foil and the side foil are sealed. A stamped-out part 20 is provided at the bottom area of the bottom foil for connecting the side foils directly to each other, i.e. also at the bottom area. As a result, a side foil/side foil direct seal or weld 18 is obtained in the bottom area. After filling of the foil-lined bag, the upper edge is closed with a further weld-sealing line 14. Fig. 5 is a side view of a foil-lined bag 2 that has not been filled and closed. The width is denoted by x. The foil may be, for example, a laminated aluminum foil. The terms welded joint line, weld or seal referred to in this description refer to the parts of the respective foils that are directly welded or sealed, respectively, as well as the adhesive areas and thermal bonds.

Fig. 6a and 6b show the same foil-lined bag after filling and closing. The two portions correspond generally to lines I and II of the unfilled foil-lined pouch depicted in fig. 5. Almost at the centre line of the foil-lined pouch of which fig. 6a is a part, the bottom foil 8 is folded open to a considerable extent and there is a space between the side foils 6 and 4 for filling material. Near the side edges of the foil-lined bag the bottom foil 8 is folded to a greater extent and the space between the side foils 6 and 4 decreases with decreasing distance from the foil-lined bag. As shown in fig. 4 and 5, the side foils 4 and 6 are directly connected to each other along the welding sealing line 10 and the side foil/side foil welding or sealing point 18 on the side edges themselves. The stability and reliable upright position of the foil-lined pouch is ensured by the side foil/side foil welds or sealing points 18.

Fig. 1 is a schematic diagram showing an apparatus according to the present invention. The side foils 4 and 6 are continuously wound off from the supply rolls, where the supply rolls are of no further interest, and the side foils 4 and 6 are then fed to the sealing device 36 by means of the deflection roll 46 and the feed roll 40, the sealing device 36 comprising a sealing head 42 which can be moved up and down. The feed direction is indicated by 50. The base foil 8 is pulled from the supply roll 48 and moved by the feed roll 40 in a feed direction 52. 30 denotes a punching device and 32 an optical measuring device, such as a light barrier, which is located at a position perpendicular to the feeding direction 52 and corresponds to the punching device 30. 34 denotes folding means for folding the bottom foil in the longitudinal direction 52, as far as its exact manner of operation is not relevant here. In another embodiment, the folding device 34 may be arranged upstream of the punching device 30, so that the punching device punches out on the already folded bottom foil. 38 denotes a cutting device comprising a cutting knife 44 having a width equal to the entire width of the foil. 62 signal lines connecting the bottom foil feed roll 48, the punching means 30 and the light barrier 32 to the control unit 60. And 64 a transport device for the folded foil.

Fig. 2 shows the bottom foil 8 after it has passed the punching means 30. Every other distance x corresponding to the width of an unfilled foil-lined pouch is provided with a punched hole 20, which is at a distance y from the centre line 22. The dimensions y and x are a few millimetres and centimetres respectively, depending on the dimensions of the finished foil-lined bag 2.

Fig. 3 shows the arrangement according to fig. 1 in a state after a number of foil bags have passed the sealing device 36 and before they have passed the cutting device 38. The height of the foil-lined bag in a direction perpendicular to the transport direction 50 is indicated by z. 24 denotes the cutting line at which a row of foil bags is to be cut by the cutter 44 of the cutting device 38. The centre line of the bottom foil 8 is indicated at 22 (fig. 2), which in the state after the sealing or welding process represents the folded edge.

The method according to the invention, when using the described embodiments, is implemented as follows: the feeding device 40 may for example be a rotating roller which carries both the side foils 4, 6 and the bottom foil 8. The base foil 8 is here wound off from a supply roll 48 (see fig. 1). Downstream of the supply roll 48 a punching hole 20 is punched in the base foil by means of a punching device 30, the punching hole 20 being arranged symmetrically with respect to the centre line. The bottom foil then passes through a light barrier 32, the position of which depends on the position of the punched hole. Each time the punch hole 20 passes the flag 32, an electrical signal is generated and sent to the control unit 60 via signal line 62.

Further, the control unit 60 receives signals regarding the speed of the feed roll 48 and the press rate of the press device 30. The control unit 60 calculates the distance to the light barrier 32 that the punched hole 20 is expected to reach from the speed and the punching rate of the bottom foil and compares the calculated value with the signal emitted by the light barrier 32.

In case no bottom foil and thus no light barrier 32 is present, and in case no punched hole 20 and thus no light barrier 32 is present, the calculated measurement signal does not correspond to the measurement signal of the light barrier 32, and the control unit 60 then issues an alarm signal which can be used, for example, to stop the entire apparatus. Similarly, in the event of a malfunction, such as a foil break downstream of the stamping and folding device, the light barrier 32 will not send any signal. In this case, no foil is required and the signal state does not change.

In normal operation, in the embodiment shown in the figures, the punched bottom foil 8 is folded along the centre line 22 in the folding device 34 and introduced in between the side foils 4 and 6. The sealing device 36, as shown in fig. 3, seals the side foils along the welding sealing line 10 in a manner known per se. The side foils 4 and 6 are not directly joined to each other in the bottom area 16, except in the area 18 where the punched hole of the bottom foil 8 is located. The side foils 4, 6 and the bottom foil 8, which are placed together and sealed, are transported further forward in the direction 64 and cut along the line 24. The cut edges 24 are positioned so that the welded sealing line 10 between two adjacent foil-lined pouches can be separated and extend through the punched hole 20 of the bottom foil 8. It is thereby ensured that the side foils at the bottom of the foil-lined bag 2 can also be directly sealed to each other via the punched holes 20.

The method according to the invention ensures that the punched holes 20 do exist in the base foil. In this way, a further inspection step for determining whether the side foils 4, 6 are also sealed to each other in the bottom region can be omitted. Such time consuming inspection procedures can prolong the production process of foil lined bags rather than being desirable. Furthermore, in the embodiment shown, it can be ensured that the bottom foil 8 is actually introduced in between the side foils 4, 6 and that there are no broken foils, which in turn can further improve the reliability.

Claims (27)

1. A method of producing a foil lined bag comprising the steps of:

a) supplying two foils (4, 6) forming the side walls of the foil-lined pouch (2);

b) supplying the base foil (8), wherein at least punched holes (20) are punched in the base foil (8) during the supply, said punched holes (20) being spaced apart in the longitudinal direction (52) of the base foil by a distance (x) corresponding to the width of the foil liner pocket (2), and folding the base foil (8) along a centre line (22) of the base foil (8) extending parallel to the longitudinal direction (52) of the base foil (8), the arrangement of the punched holes (20) being substantially symmetrical to the centre line (22), and

wherein in step b) the punched hole is measured to determine whether a punched hole (20) is produced;

c) -stacking the 1 st side foil (4), the folded bottom foil (8) and the 2 nd side foil (6) on top of each other;

d) -joining the series of layers (4, 8, 6) at a future side edge (10) of the foil-lined pouch (2) such that the side edges are only directly connected to each other by the punched hole (20) when the bottom foil (8) is positioned in a position between the side foils (4, 6); and

e) the connected series of foil layers (4, 8, 6) are cut such that the side connecting portions (10) are separated between two foil bags (2), respectively.

2. The method of claim 1, wherein the step of joining comprises a sealing or welding process.

3. A method according to any one of claims 1 and 2, characterized in that in step b) the punching process is performed before the folding process.

4. The method of claim 1, wherein in step b), the folding process is performed before the stamping process.

5. A method as claimed in claim 1, characterized in that the punched hole is measured optically to determine whether a punched hole (20) has been produced.

6. A method as claimed in claim 1, characterized in that the optical method of measuring the punched hole, which determines whether the punched hole (20) has been produced, is by means of a proximity switch.

7. A method according to claim 1, characterized in that at least two punched holes (20) are punched symmetrically side by side in relation to the centre line (22) of the base foil (8).

8. A method according to claim 1, characterized in that in step b) a foil measurement is performed to determine whether a base foil (8) is present.

9. Method according to claim 8, characterized in that foil measurement is used to determine whether a base foil (8) is required.

10. The method of claim 8, wherein the foil measurement uses optical methods.

11. The method of claim 8, wherein the foil measurement is by at least one proximity switch.

12. Method according to claim 8, characterized in that the punched hole measurement is performed by means of the same measuring device (32).

13. A method as claimed in any one of claims 5 and 10, characterized in that the optical measurement is carried out using at least one light barrier.

14. A method as claimed in claim 1, characterized in that two side foils (4, 6) are supplied having a width corresponding to the height of a number of foil bags (2) and a corresponding number of bottom foils (8) are supplied.

15. A foil-lined bag production plant for carrying out the method of claim 1, comprising 1 st and 2 nd supply means for supplying side foils (4, 6) for use as side walls of a foil-lined bag (2), at least one 3 rd supply means (48) for supplying a foil material for a bottom foil (8) of the foil-lined bag, a punching means (30) for punching a punching hole (20) in the bottom foil (8) symmetrically arranged with respect to a centre line (22) of the bottom foil (8), a folding means (34) for folding the bottom foil (8), 1 st measuring means for detecting the punching hole (20), connecting means (36) for connecting the side foils (4, 6) and the bottom foil (8), and cutting means (38) for cutting the connected foil along the connecting area (10).

16. An apparatus according to claim 15, characterized in that the connecting means (36) is a sealing means.

17. An apparatus according to any one of claims 15 and 16, characterized in that the 1 st measuring device is an optical measuring device.

18. An apparatus according to any of claims 15 and 16, characterized in that the 1 st measuring device is a proximity switch.

19. An apparatus according to claim 15, characterized in that the 2 nd measuring device is arranged to detect the presence of the base foil (8).

20. An apparatus according to claim 19, characterized in that the 2 nd measuring device is an optical measuring device.

21. The apparatus of claim 19, wherein the 2 nd measuring device is a proximity switch.

22. The apparatus of claim 17, wherein the optical measuring device is a light barrier.

23. The apparatus of claim 20, wherein the optical measuring device is a light barrier.

24. An arrangement as claimed in claim 19, characterized in that the 1 st and 2 nd measuring means are formed by a joint measuring device (32).

25. An apparatus according to claim 15, characterized in that a number of stamping devices are arranged one after the other in a direction perpendicular to the longitudinal direction (52) of the base foil (8), and that a corresponding number of measuring devices (32) are arranged one after the other in a direction perpendicular to the longitudinal direction (52) of the base foil (8).

26. The apparatus as claimed in claim 15, characterized in that the folding device (34) is arranged upstream of the punching device (30).

27. The apparatus as claimed in claim 15, characterized in that the folding device (34) is arranged downstream of the punching device (30).