Advancing device for advancing a film web in a bag filling installation

Abstract

The invention relates to an advancing device (10) for advancing a film web (200) in a bag filling installation (100, having a main advancing drive (20) with at least one driven main advancing roller (22) for advancing the film web (200), wherein for an adjustment of the tensile stress of the film web (200) in the transport direction (T) of the film web (200) an auxiliary advancing drive (30) is disposed before the main advancing drive (20) with at least one driven auxiliary advancing roller (32) for advancing the film web (200).

Claims

1. A advancing device in a bag filling installation for advancing a film web, comprising a main advancing drive with at least one driven main advancing roller for advancing the film web, wherein for an adjustment of the tensile stress of the film web in the transport direction (T) of the film web an auxiliary advancing drive is disposed before the main advancing drive and spaced apart from the main advancing drive, the auxiliary advancing drive having at least one driven auxiliary advancing roller for advancing the film web, wherein at least one of the main advancing drive or the auxiliary advancing drive have at least one freely rotatable film roller and wherein the freely rotatable film roller is disposed in such a way that an S-shaped loop (S) of the film web forms along the transport direction (T) of the film web between the freely rotatable film roller and the auxiliary advancing roller and/or between the freely rotatable film roller and the main advancing roller wherein the S-shaped loop (S) of the film web is in abutment with the freely rotatable film roller and the auxiliary advancing roller and/or with the freely rotatable film roller and the main advancing roller wherein a total looping angle of the film web for the auxiliary advancing roller and/or for the main advancing roller arid/or for the freely rotatable film roller at least 180, wherein an electronic coupling device is connected in a signal communicating manner to the auxiliary advancing drive of the auxiliary advancing roller and the main advancing drive of the main advancing roller for a setting of a respective advancing speed to be carried out electronically.

2. The advancing device according to claim 1, wherein the main advancing drive is driven at a different advancing speed from the auxiliary advancing drive.

3. The advancing device of claim 2 wherein the main advancing drive is driven at a higher advancing speed than the auxiliary advancing drive.

4. The advancing device according to claim 1, wherein the main advancing drive and the auxiliary advancing drive are operated so that they are correlated with one another on a common cycle.

5. The advancing device of claim 4 wherein the main advancing drive and the auxiliary advancing drive are operated so that they are correlated with one another synchronously in the common cycle.

6. The advancing device according to claim 1, wherein the main advancing drive and/or the auxiliary advancing drive have a pressing device for generating a pressing force between the film web and the main advancing roller and/or the auxiliary advancing roller.

7. A bag filling installation for filling bags with bulk material, having an advancing device for advancing a film web, wherein the advancing device has the features of claim 1.

8. A method for the adjustment of a tensile stress of a film web in a bag filling installation, with the advancing device of claim 1, comprising the following steps: predetermination of a tensile stress for the tensile stress on the film web, synchronous, advancing of the film web correlated with a main advancing drive and an auxiliary advancing drive disposed in the transport direction (T) of the film web before the main advancing drive while maintaining the predetermined tensile stress value.

9. The advancing device according to claim 1 wherein a total looping angle of the film web for each S-shaped loop (S) at least 180 which provides an abutment between the main advancing drive and the auxiliary advancing drive.

10. The advancing device according to claim 1 wherein each of the main advancing drive and the auxiliary advancing drive have the freely rotatable film roller and wherein at least one of the freely rotatable film rollers is disposed in such a way that the S-shaped loop (S) of the film web forms along the transport direction (T) of the film web between the freely rotatable film roller and the auxiliary advancing roller and/or between the freely rotatable film roller and the main advancing roller.

11. The advancing device according to claim 1 wherein the electronic coupling device is configured as a control device.

12. An advancing device in a bag filling installation for advancing a film web comprising a main advancing drive with at least one driven main advancing roller for advancing the film web, wherein for an adjustment of the tensile stress of the film web in the transport direction (T) of the film web an auxiliary advancing drive is disposed before the main advancing drive and spaced apart from the main advancing drive, the auxiliary advancing drive having at least one driven auxiliary advancing roller for advancing the film web, wherein at least one of the main advancing drive or the auxiliary advancing drive have at least one freely rotatable film roller and wherein the auxiliary advancing drive is disposed upstream of the main advancing drive and simultaneously downstream of a buffer device and, wherein the freely rotatable film roller is disposed in such a way that an S-shaped loop (S) of the film web forms along the transport direction (T) of the film web between the freely rotatable film roller and the auxiliary advancing roller and/or between the freely rotatable film roller and the main advancing roller, wherein the S-shaped loop (S) of the film web is in abutment with the freely rotatable film roller and the auxiliary advancing roller and/or with the freely rotatable film roller and the main advancing roller, wherein a total looping angle of the film web is at least 180, wherein an electronic coupling device is connected in a signal communicating manner to the auxiliary advancing drive of the auxiliary advancing roller and the main advancing drive of the main advancing roller for a setting of a respective advancing speed to be carried out electronically.

Description

(1) Further advantages, features and details of the invention are apparent from the following description in which embodiments of the invention are described in detail with reference to the drawings. In this case the features mentioned the claims and in the description may in each case be essential to the invention individually or in any combination. In the drawings, in each case schematically:

(2) FIG. 1 shows a representation of a bag filling installation according to the invention,

(3) FIG. 2 shows an embodiment of an advancing device according to the invention,

(4) FIG. 3 shows a further embodiment of an advancing device according to the invention, and

(5) FIG. 4 shows a further embodiment of an auxiliary advancing drive according to the invention.

(6) A bag filling installation 100 according to the invention is illustrated schematically in FIG. 1. The start of the process takes place to the right of a supply roller, from which a film web 200 is continuously unwound. By means of a buffer device 110, which is designed in reciprocating operation as a dancer device, the continuous operation of conveying the film web 200 is converted into a subsequent cycling of the operation of conveying the film web 200.

(7) An advancing device 10 according to the invention is disposed starting from the buffer device 110. Thus an auxiliary advancing drive 30, by means of which a main advancing drive 20 is reached via different guide rollers by the film web 200, is disposed directly downstream of the buffer device 110. The following station 170 is the base seam sealing station and the cutting device for cutting to length of individual bag portions. By means of gripping devices operated in reciprocating motion the bag portions are transported further towards the left to the next station 170, which has a schematically illustrated filling hopper. In the next station 170 to the left the filled bag portion is provided with a top seam which is cooled in the last, leftmost station 170.

(8) In FIG. 1 it can be readily seen that without the auxiliary advancing drive 30 from the film web 200 the continuous conveying exclusively by the buffer device 110 is converted into the cyclical feed the sheet of the film web 200. If the transport of the main advancing drive 20 stops, then further swinging or further conveying of the film web 200 takes place over a short time period and thus a reduction in the tensile stress on the film web 200 takes place in the region of the main advancing drive 20. In the past the buffer device 110 had first to begin again, to swing the reciprocating operation back, in order to re-establish the required tensile stress. According to the invention the auxiliary advancing drive 30 blocks this described effect of the further swinging or further conveying of the film web 200. By correlation of the advancing speeds of the two advancing drives 20 and 30 a defined tensile stress can be set to be substantially constant for all usage situations (stationary and driven).

(9) A further embodiment of an advancing device 10 according to the invention is shown schematically in FIG. 2. Here, moreover, the auxiliary advancing drive 30 is provided with a pressing device 60 which exerts a spring force on a freely rotatable film roller 34. In addition to the main advancing roller 22, the main advancing drive 20 is also provided with a freely rotatable film roller 24. In this case it is sufficient if one of the two advancing rollers 22 or 32 has an active driving device (not shown). The two advancing rollers 22 and 32 have a mechanical coupling device 40 which here has a belt 44 as belt drive. By means of two belt pulleys in each case a transmission 42 is formed on the respective advancing roller 22 and 32, in order to be able to ensure a synchronously cyclical implementation of the two advancing drives 20 and 30. At the same time there is a reduction gear or a step-up gear, so that a defined lag for the auxiliary advancing drive 30 is ensured relative to the main advancing drive 20. This leads to an explicit adjustment of the tensile stress in the film web 200 over the run along the transport direction T.

(10) FIG. 3 shows an embodiment of an advancing device 10 according to the invention. This is in principle configured similarly to the embodiment of FIG. 2, but here an electronic coupling device 50 is provided. As the dotted lines show, this is connected in a signal-communicating manner to two driving devices as motor 70 of the two advancing roller 22 and 32. Thus a setting of the respective advancing speed can be carried out here explicitly and substantially electronically, preferably digitally. Thus even during operation a variation in the difference between the advancing speeds and thus a variation in the tensile stress in the film web 200 is possible.

(11) FIG. 4 shows on an enlarged scale a particularly advantageous embodiment of an auxiliary advancing drive 30. Here the advancing roller 32 and the freely rotatable film roller 34 are constructed relative to one another in such a way that an S-shaped loop S forms along the transport direction T for the film web 200. The total looping angle of the film web 200 within the auxiliary advancing drive 30 is brought here to more than approximately 180. Thus a particularly strong abutment is made available, so that even at high transport speeds, at high transport forces and/or at high tensile stresses a sufficient abutment can be provided between the two advancing drives 20 and 30.

(12) The preceding explanation of the embodiments describes the present invention exclusively in the context of examples. Of course individual features of the embodiments can be freely combined with one another, if technically practical, without departing from the scope of the present invention.

LIST OF REFERENCE SIGNS

(13) 10 advancing device 20 main advancing drive 22 main advancing roller 24 freely rotatable film roller 30 auxiliary advancing drive 32 auxiliary advancing roller 34 freely rotatable film roller 40 mechanical coupling device 42 transmission 44 belt 50 electronic coupling device 60 pressing device 70 motor 100 bag filling installation 110 buffer device 170 station 200 film web S S-shaped loop T transport direction