METHOD AND TUBULAR BAG MACHINE FOR THE CONTINUOUS PRODUCTION OF BLOCK-BOTTOM BAGS

Abstract

The invention relates to a tubular bag machine and a method for the continuous production of block-bottom bags (10) comprising two side areas folded in at the bottom and a transversally sealed bottom seam, the bottom seam comprising at least one first portion with a twin film web and at least one second portion with a quadruple film web, and the bottom seam running in the base surface des block-bottom bag (10). Once a bottom seam has been transversally sealed, the front block-bottom bag (10) is severed from the film web (03) by applying a film cut, and the transverse sealing jaws (09) moving in the conveying direction are opened far enough for the transverse sealing jaws (09) to exert essentially no more pressure on the bottom seal, and the transverse sealing jaws (09) moving in the conveying direction simultaneously move perpendicular to the conveying direction, the bottom seam thus being folded over perpendicular to the conveying direction, and the folded-over bottom seam is fixed in such a manner that it runs in the base surface of the block-bottom bag (10)

Claims

1. A method for the continuous production of block-bottom bags (10) comprising two side areas folded in at the bottom and a transversally sealed bottom seam (12), the bottom seam (12) comprising at least one first portion with a twin film web and at least one second portion with a quadruple film web, and the bottom seam (12) running in the base surface (13) of the block-bottom bag (10), characterized in that a) once a bottom seam (12) has been transversally sealed, the front block-bottom bag (10) is severed from the film web (03) by applying a film cut; b) the transverse sealing jaws (09) moving in the conveying direction are opened far enough for the transverse sealing jaws (09) to exert essentially no more pressure on the bottom seam (12); c) the transverse sealing jaws (09) moving in the conveying direction simultaneously move perpendicular to the conveying direction, the bottom seam (12) thus being folded over perpendicular to the conveying direction; d) the folded-over bottom seam (12) is fixed in such a manner that it runs in the base surface (13) of the block-bottom bag (10).

2. The method according to claim 1, characterized in that the folded-over bottom seam (12) moving in the conveying direction is at least partially sealed to the base surface (13) of the block-bottom bag (10).

3. The method according to claim 2, characterized in that the bottom seam (12) is sealed by applying a sealing pressure using a sealing tool without any additional heat input.

4. The method according to claim 1, characterized in that the block-bottom bags (10) have an opening opposite the inner side of the base surface (13), the opening allowing the block-bottom bag to be subsequently filled.

5. The method according to claim 1, characterized in that the film web (03) used for producing the block-bottom bags (10) comprises a paper layer to which the sealing layer is attached.

6. The method according to claim 5, characterized in that the film web (03) used for producing the block-bottom bags (10) contains a paper content of at least 95%.

7. A tubular bag machine (01) comprising a film web (03) configured to be unwound from a supply roll (02), a shaping shoulder (04) for shaping the film web (03) into a film tube (05), a longitudinal sealing mechanism for sealing the film tube (05) along a longitudinal seam, and a transverse sealing mechanism (08) having transverse sealing jaws (09) for producing bottom seams (12), the transverse sealing jaws (09) being configured to move against each other and transversally seal the film tube (05), characterized in that the tubular bag machine (01) comprises a pressing stamp whose stamp surface is configured to come into contact with the inner side of the base surface (13) of a block-bottom bag (10), the pressing stamp being configured to be driven in the conveying direction by a drive, and the pressing stamp being configured to be pressed against the inner side of the base surface (13) of the block-bottom bag (10) with a predefined pressure during the movement.

8. The tubular bag machine according to claim 7, characterized in that the pressing stamp is a sealing stamp.

9. The tubular bag machine according to claim 8, characterized in that the sealing stamp is a forming tube (06), the film web (03) being guided on the outer side of the forming tube (06).

10. The tubular bag machine according to claim 7, characterized in that the tubular bag machine comprises a folding mechanism configured to fold the bottom seam (12) over perpendicular to the conveying direction.

11. The tubular bag machine according to claim 10, characterized in that the folding mechanism is a shifting mechanism configured to simultaneously shift the transverse sealing jaws (09) perpendicular to the conveying direction as they are moving in the conveying direction.

12. The tubular bag machine according to claim 11, characterized in that the two transverse sealing jaws (09) are configured to be pressed against each other by a toggle drive, the shifting mechanism being configured to shift the core point of the toggle drive perpendicular to the conveying direction.

13. The method according to claim 1, characterized in that the folded-over bottom seam (12) moving in the conveying direction is at least partially sealed to the base surface (13) of the block-bottom bag (10); the bottom seam (12) is sealed by applying a sealing pressure using a sealing tool without any additional heat input; the block-bottom bags (10) have an opening opposite the inner side of the base surface (13), the opening allowing the block-bottom bag to be subsequently filled; the film web (03) used for producing the block-bottom bags (10) comprises a paper layer to which the sealing layer is attached; the film web (03) used for producing the block-bottom bags (10) contains a paper content of at least 95%.

14. The tubular bag machine according to claim 7, characterized in that the pressing stamp is a sealing stamp; the sealing stamp is a forming tube (06), the film web (03) being guided on the outer side of the forming tube (06); the tubular bag machine comprises a folding mechanism configured to fold the bottom seam (12) over perpendicular to the conveying direction; the folding mechanism is a shifting mechanism configured to simultaneously shift the transverse sealing jaws (09) perpendicular to the conveying direction as they are moving in the conveying direction; the two transverse sealing jaws (09) are configured to be pressed against each other by a toggle drive, the shifting mechanism being configured to shift the core point of the toggle drive perpendicular to the conveying direction.

Description

[0017] An embodiment of the invention is schematically illustrated in the drawings and is explained below by way of example.

[0018] FIG. 1 is a side view of a schematically illustrated tubular bag machine for carrying out the method according to the invention;

[0019] FIG. 2 shows the transverse sealing jaws of the tubular bag machine of FIG. 1 in a first stage of the method according to the invention;

[0020] FIG. 3 shows the transverse sealing jaws of the tubular bag machine of FIG. 1 in a second stage of the method according to the invention;

[0021] FIG. 4 shows the transverse sealing jaws of the tubular bag machine of FIG. 1 in a third stage of the method according to the invention;

[0022] FIG. 5 shows the transverse sealing jaws of the tubular bag machine of FIG. 1 in a fourth stage of the method according to the invention.

[0023] FIG. 1 shows a schematically illustrated tubular bag machine 01, only the parts of the tubular bag machine 01 that are necessary for understanding the invention being shown in FIG. 1. A film web 03 is unwound from a supply roll 02 and then shaped into a film tube on a shaping shoulder 04. The film web 03 is a paper web coated with a sealing layer, the paper content being higher than 95%.

[0024] The film tube 05, which is driven by a film drive 07, slides downward on the outside of the forming tube 06, the film tube 05 being sealed longitudinally parallel to its conveying direction by means of a longitudinal sealing mechanism (not shown in FIG. 1). The conveying speed of the film web 03 is monitored by a suitable sensor system. The forming tube 06 is designed in the manner of a sealing stamp at its end face and can be moved upward or downward in the direction of the conveying direction of the film web 03 by means of a drive (not shown). The function of the sealing stamp in the forming tube 06 is explained in more detail below.

[0025] Below the forming tube 06 there is a transverse sealing mechanism 08 having two transverse sealing jaws 09 for producing transverse sealing seams and serving to transversally seal the film tube 05 to form individual tubular bags 10. In addition, the tubular bag machine 01 comprises two folding plates (not shown in FIG. 1) configured to fold the film web 03 in laterally to produce a block-bottom bag. A severing member 11 designed as a severing knife is integrated into the right-hand transverse sealing jaw 09 and allows the tubular bags to be separated from each other after the transverse sealing seam has been applied.

[0026] The tubular bag machine 01 shown in FIG. 1 can be used to produce unfilled block-bottom bags 10 which initially do not yet have a top seam. These unfilled block-bottom bags can then be filled with a product in a subsequent process stage and then sealed by applying a top seam.

[0027] FIG. 2 shows the transverse sealing jaws 09 and the tubular bag 10 during the transverse sealing of the bottom seam 12. The two transverse sealing jaws 09 are moved downward at essentially the same conveying speed as the conveying speed of the film web 03, and the transverse sealing jaws 09 are pressed against each other at the same time using a toggle drive. By heating the transverse sealing jaws 09, the film web 03 is then sealed to produce the bottom seam 12. Subsequently, the severing member 11 is deployed and the lowest block-bottom bag 10 is cut off.

[0028] FIG. 3 shows the transverse sealing jaws 09 in the subsequent process phase after the lowermost block-bottom bag has been cut off. As soon as the bottom seam 12 is sufficiently sealed, the transverse sealing jaws 09 are moved a little further apart, continuing to move downward at the conveying speed of the film web 03. In this way, the bottom seam 12 is released.

[0029] Then, as shown in FIG. 4, the core point of the toggle drive is moved sideways to drive the two transverse sealing jaws 09, the distance between the two transverse sealing jaws 09 remaining the same. By moving the left transverse sealing jaw 09 sideways, the bottom seam 12 is folded over and lies flat against the outer side of the film web 03 at the base surface 13. At the same time, the forming tube 06, which is also a sealing stamp, is moved downwards, the travel speed of the forming tube 06 being greater than the speed of the two transverse sealing jaws 09. In this manner, the lower end face of the forming tube 06 approaches the upper side of the transverse sealing jaws 09.

[0030] As can be seen in FIG. 5, the forming tube 06 is finally pressed against the upper side of the base surface 13 from above so that the bottom seam 12 is partially sealed between the end face of the forming tube 06 and the upper side of the left transverse sealing jaw 09. A supply of thermal energy is not necessary, as there is still sufficient residual heat in the bottom seam 12. The pressure of the forming tube 06 against the bottom seam 12 causes the bottom seam 12 to be slightly sealed to the base surface 13 of the tubular bag 10.