EP2233419B1 - Device for regulating the web edge of a film - Google Patents

Description

The invention relates to a device for web edge control of a film, in particular for film guidance in blister machines of the pharmaceutical industry. Such a web edge control, which is considered as the closest prior art is in the US 3,069,021 disclosed.

Such devices for web edge control of films have long been known in blister machines. In the manufacture of blister packs, a mold sheet and a cover sheet are sealed together in the blister machine, with blister pens being prefilled into the mold sheet which are filled with pharmaceutical products. For film guidance of both the forming film and the cover sheet a web edge control is necessary because the films tend during their transport through the machine to run transversely to the direction. The reason for this are parallelism deviations of the deflection rollers and guide rollers as well as inaccurately cut coils of the molding film or cover film.

In order to regulate this running of the films, the mold films are previously performed on the last deflection roller before the forming station of two guide plates transversely to the direction.

If it is signaled by a sensor provided for this purpose that the molding film threatens to run out of a tolerance field, the guide plates are moved by motor means transversely to the film running direction in order to correct the direction of travel of the film.

This possibility of film displacement by means of lateral guide plates leads, in particular with aluminum foils, to the fact that they do not follow the displacement of the guide plates, but that the foil edges accumulate on the guide plates and turn over.

With PVC films, this problem is not due to their greater rigidity to this extent, but it comes to fine dust abrasion of the PVC film on the guide plates.

The present invention is therefore an object of the invention to provide a device for web edge control of a film, with the web space control of all types of films can be performed in a small space and in a simple, safe and gentle way.

This object is solved by the features of claim 1.

According to the invention, the device for web edge control of a film on a first and a second pulley, which are arranged parallel to each other, also at least one drive for axially opposing displacement of the pulleys, a sensor for detecting the position of the film, a means for varying the ratio between the Friction of the film on the first guide roller and the friction of the film on the second guide roller, and a control device for controlling the at least one drive for axially opposing displacement of the guide rollers and means for varying the ratio between the friction of the film on the first guide roller and the Friction of the film on the second deflection roller based on the position of the film detected by the sensor.

By this structure, a web edge control of all types of films is possible in a secure manner, with form-fitting guide elements, which have the disadvantages mentioned above, need not be used. As a result, an endless, yet extremely gentle web edge control is possible for the films.

In a first embodiment, the deflection rollers are arranged side by side in the axial direction in such a way that the film extends over its width over at least a portion of each of the two deflection rollers. By this division of the bearing surface of the film influencing the friction of the film on each of the pulleys is made possible in a simple manner.

Preferably, the deflection rollers are mounted on the same shaft, which has a first thread in the region of the first deflection roller and a second thread in the region of the second deflection roller, wherein the first thread and the second thread are in opposite directions and the drive for axially opposing displacement of the deflection rollers, the shaft drives. With this configuration, a particularly simple control of the axially opposite displacement of the pulleys by means of a single drive is possible.

For influencing the friction between the film and each deflection roller, the means for varying the ratio between the friction of the film on the first deflection roller and the friction of the film on the second deflection roller comprises two pressure rollers which is associated with the first pinch roller of the first deflection roller and the second pinch roller of the second deflection roller.

In this case, each pressure roller is preferably displaceable in the axial direction simultaneously with the associated deflection roller. In this way, a lateral displacement of the film take place, which is triggered by a pressing of the pressure roller to the film and thus to the respective guide roller and the simultaneous lateral displacement of the guide roller and the pressure roller.

Preferably, each pinch roller is connected to the associated deflection roller such that each pinch roller is displaceable by means of the drive for axially opposing displacement of the deflection rollers in the axial direction simultaneously with the associated deflection roller. Thus, the synchronicity of the movement of pulley and associated pinch roller is ensured in a simple manner.

In an alternative embodiment, the deflection rollers are arranged side by side in the radial direction such that the film only extends over a deflection roller, wherein each deflection roller has its own shaft. In this embodiment, films can be processed in which the film retraction force is relatively high.

In this case, both shafts preferably have opposing threads, and the drive for axially opposing displacement of the pulleys drives both shafts simultaneously. Alternatively, one drive per shaft can also be provided in each case.

In this case, the means for varying the ratio between the friction of the film on the first deflection roller and the friction of the film on the second deflection roller preferably has a bearing for the shafts, which is designed to be pivotable. As a result, it is easy to switch over from one course of the film around the one shaft to a course of the film around the other shaft.

Although many design options exist, it is preferred that the first deflection roller has a slightly greater distance from the pivot axis than the second deflection roller. In particular, when the bearing is now simultaneously pivotable at between 92 ° and 105 ° degrees, preferably between 93 ° and 98 ° degree, the bearing can thus be simple Way between two positions are pivoted, in each of which only one deflection roller has a connection with the film.

In all embodiments, it is advantageous that at least one sensor for detecting the end positions of the travel of each deflection roller is present, wherein the sensor is connected to the control device. Thus, the direction of the drive for the axially opposite displacement of the pulleys can always be changed at the right time.

Fig. 1

ist eine schematische Perspektivansicht einer ersten Ausführungsform der erfin- dungsgemäßen Vorrichtung zur Bahnkantenregelung einer Folie;

Fig. 2

ist eine Querschnittsansicht auf die Ausführungsform von Fig. 1 aus Blickrichtung Z;

Fig. 3

entspricht der Darstellung aus Fig. 2 bei einer äußeren Endposition der beiden Um- lenkrollen;

Fig. 4

entspricht der Darstellung aus Fig. 3, wobei sich die Umlenkrollen wieder auf dem Rückweg in die zentrale Position befinden;

Fig. 5

ist eine schematische Perspektivansicht der wichtigsten Elemente einer zweiten Ausführungsform der erfindungsgemäßen Vorrichtung zur Bahnkantenregelung ei- ner Folie;

Fig. 6

ist eine Seitenansicht der Vorrichtung aus Fig. 5; und

Fig. 7

entspricht Fig. 6, wobei die Lagerplatte derart geschwenkt ist, dass die Folie nun- mehr um die zweite Umlenkrolle läuft.

Further features and advantages of the present invention will become apparent from the following description with reference to the drawings.

Fig. 1

is a schematic perspective view of a first embodiment of the inventive device for web edge control of a film;

Fig. 2

is a cross-sectional view of the embodiment of Fig. 1 from the direction Z;

Fig. 3

corresponds to the illustration Fig. 2 at an outer end position of the two deflecting rollers;

Fig. 4

corresponds to the illustration Fig. 3 , wherein the pulleys are back on the way back to the central position;

Fig. 5

is a schematic perspective view of the most important elements of a second embodiment of the inventive device for web edge control of a film;

Fig. 6

is a side view of the device Fig. 5 ; and

Fig. 7

corresponds to Fig. 6 wherein the bearing plate is pivoted such that the foil now runs around the second deflection roller.

In Fig. 1 to 4 a first embodiment of the device according to the invention for web edge control of a film is shown. Foil types are in particular films for blister packs in question, as well as the invention but also on cover films for blister packs and a variety of other types of films applicable, even in other industries.

The device for web edge control of a film 2 comprises a housing 4 in which a first deflection roller 6 and a second deflection roller 8 are arranged parallel to one another. In the in Fig. 1 to 4 1, the deflection rollers 6, 8 are arranged side by side in the axial direction in such a way that the film 2 extends over at least a portion of each of the two deflection rollers 6, 8 in width. The film 2 should be less wide than the total width of both pulleys 6, 8. The film 2 comes from a film reel (not shown), is deflected by the deflection rollers 6, 8 and the other processing stations (heating station, forming station) in the direction of the arrow C supplied. The deflection rollers 6, 8 have a lateral surface made of, for example, plastic. Between the lateral surface and the film 2 to be conveyed a certain frictional force is generated.

A sensor 10 ( Fig. 1 ) detects the position of at least one lateral edge of the film 2 by means of optical scanning in a field of view 12 and provides signals to an unillustrated integrated control device for web edge control of the film second

The two deflection rollers 6, 8 can rotate independently of each other and are in opposite directions axially by a certain amount, for example, by about 10 mm, move toward and away from each other. Preferably, a motor drive 14 for the axially opposite displacement of the guide rollers 6, 8 is provided. It is also possible to provide two separate drives 14 for the axial displacement of the deflection rollers 6, 8.

In the example of the Fig. 1 to 4 is the sheath core of each guide roller 6, 8, on which the respective lateral surface rotates, mounted on the same shaft 16 which is formed as a spindle. In this case, a first thread (not shown) in the region of the first guide roller 6 and a second, opposite thread (not shown) in the region of the second guide roller 8 is present. The drive 14, which may be configured for example as a servomotor, now drives the shaft 16 and causes due to the opposition of the two threaded sections, the axially opposite displacement of the guide rollers 6, 8. Sensors 18 can be used to detect the axial end positions of the displacement of the guide rollers 6, 8 serve.

In Fig. 2 is the maximum approximate state of the two pulleys 6, 8 shown in Fig. 3 the maximum removed state of the two pulleys 6, 8, and in Fig. 4 an intermediate position between the two end positions.

According to the invention, the device has a means for varying the ratio between the friction of the film 2 on the first guide roller 6 and the friction of the film 2 on the second guide roller 8. In the case of Fig. 1 to 4 this means is designed such that over the two deflection rollers 6, 8 each have a smaller pressure roller 20, 22 is arranged, which can be preferably pneumatically pressed with slight pressure to the respective guide roller 6, 8 and moved away from it again. The pressure rollers 20, 22 are axially connected in each case with their associated deflection roller 6, 8, so that each pressure roller 20, 22 makes the same axial movement as its associated pulley 6, 8.

To represent the rule principle is in Fig. 2 the film 2 in an excessive manner shifted to the right, so in the transverse direction. The field of view 12 of the sensor 10 (FIG. Fig. 1 ) evaluates in the present case, the left edge of the film 2 and is a detected control deviation on the control device to the drive 14 on. In the present example, the film 2 must start from the in Fig. 2 position thus shifted to the left.

For this purpose, the left pinch roller 20 is applied with slight pressure to the left guide roller 6 and thus generates a slightly higher frictional force between the guide roller 6 and 2 film than the frictional force between the other guide roller 8 and the film. 2

On the other hand, since it has been detected by the sensor 18 that the deflecting rollers 6, 8 are axially maximally close together, the regulating device for the drive 14 will select such a direction of rotation that the deflecting rollers 6, 8 move in the direction of the arrows B (FIG. Fig. 3 ) are moved apart. With this axial displacement of the deflection rollers 6, 8, the film 2 is moved by the higher friction force on the left guide roller 6 with this in the direction of the arrow A to the left.

In Fig. 3 It is shown how the film 2 has also moved with the axial movement of the left guide roller 6 with to the left. The deflection rollers 6, 8 can be so far apart in the axial direction, until a maximum displacement has taken place and the Pulleys 6, 8 are maximally apart. The size of this travel can of course depend to some extent on the type of film to be processed and the other conditions.

In the example mentioned, the film 2 tends to always run to the right. Since the axial movement of the deflection rollers 6, 8 is limited to the outside, at some point the possibility will be used to transport the film 2 by moving apart of the deflection rollers 6, 8 to the left. This is in Fig. 3 shown, in which the pulleys 6, 8 have reached their maximum end position, which is detected by the sensor 18.

On the other hand, since the film 2 is still to be moved to the left, now the right pinch roller 22 is slightly pressed against the right guide roller 8, while the left pinch roller 20 lifts and remains exempt. The drive 14 changes the direction of rotation and thus causes the deflection rollers 6, 8 to move axially toward one another again ( Fig. 4 ). Since the pressed-right pressure roller 22 generates a greater frictional force between the right guide roller 8 and film 2, as is the case between the film 2 and the left guide roller 6, the film 2 will continue to move to the left with the right guide roller 8.

According to this principle, therefore, the control can infinitely and without any loss of time correct the bleeding of the film 2, without that form-fitting guide elements must be used.

It is also conceivable to dispense with relatively high friction between the deflection rollers 6, 8 and the film 2 on the pressure rollers 20, 22. However, a use of the pressure rollers 20, 22 is clearly preferred. The pressure rollers 20, 22 are each arranged in the illustrated example in the axially inner region of the guide rollers 6, 8, but they can also be arranged in the axial direction further outward. The lateral surface of the pressure rollers 20, 22 is usually made of an elastic material, e.g. Rubber.

In particular, for films 2 with relatively high film retraction force, a second embodiment of the web edge control according to the invention, which is schematically in Fig. 5 to 7 is shown. The two axially oppositely displaceable deflection rollers 6, 8 are arranged parallel to the axis and in the radial direction next to each other. The two deflection rollers 6, 8 are in turn moved axially in opposite directions in the direction of arrows B.

As a means for varying the ratio between the friction of the film 2 on the first guide roller 6 and the friction of the film 2 on the second guide roller 8 is here a pivotable bearing 24, in which the shafts 16 of the guide rollers 6, 8 are mounted. The film 2 always runs completely on one guide roller 6, 8, while the film 2 does not touch the other guide roller 6, 8 at all.

In Fig. 5 and 6 For example, the guide roller 6 would be active and could move the film 2 in the direction of arrow A with the axial movement. During this movement, the guide roller 8 runs back in the opposite axial direction without having contact with the film 2. For this purpose, it is advantageous if the first deflection roller 6 has a slightly greater distance from the pivot axis 26 than the second deflection roller 8. It is also advantageous if the bearing 24 can be pivoted by between 91 ° and 180 °, preferably between 92 ° and 105 ° , and more preferably between 93 ° and 98 °. The closer the value approaches 90 °, the lower problems of the film guide occur during the pivoting of the bearing 24, as will be described below.

If the adjusting path of the deflecting roller 6 is now used up, although the film 2 would still have to be displaced in the same direction, the bearing 24 can pivot ( Fig. 7 ), so that now the film 2 is guided exclusively by the guide roller 8. This again has the ability to move the film 2 in the same direction (arrow A) on.

Also in this embodiment, it is possible to increase the friction between the guide roller 6, 8 and 2 film by the use of a pressure roller.

Overall, a device for web edge control was created with which irregularities in the film guide can be compensated in a simple, safe and gentle manner.

Claims (12)

1. Device for controlling edges of a web of sheeting (2), comprising a first deflecting roller (6) and a second deflecting roller (8) arranged parallel to each other, at least one drive (14) for shifting the deflecting rollers (6, 8) in opposite axial directions, a sensor (10) for detecting the position of the sheeting (2), a means (20, 22, 24) for changing the ratio between the friction of the sheeting (2) on the first deflecting roller (6) and the friction of the sheeting (2) on the second deflecting roller (8), and a control device for controlling the at least one drive (14) for shifting the deflecting rollers (6, 8) in opposite axial directions and for controlling the means (20, 22, 24) for changing the ratio between the friction of the sheeting (2) on the first deflecting roller (6) and the friction of the sheeting (2) on the second deflecting roller (8) based on the position of the sheeting (2) as detected by the sensor (10).
2. Device according to claim 1, characterised in that the deflecting rollers (6, 8) are arranged adjacent to each other in an axial direction in such a way that the sheeting (2) passes breadthways over at least a portion of each of the two deflecting rollers (6, 8).
3. Device according to claim 2, characterised in that the deflecting rollers (6, 8) are mounted on the same shaft (16), which has a first thread in the region of the first deflecting roller (6) and a second thread in the region of the second deflecting roller (8), wherein the first thread and the second thread turn in opposite directions and the drive (14) for shifting the deflecting rollers (6, 8) in opposite axial directions drives the shaft (16).
4. Device according to either claim 2 or claim 3, characterised in that the means (20, 22, 24) for changing the ratio between the friction of the sheeting (2) on the first deflecting roller (6) and the friction of the sheeting (2) on the second deflecting roller (8) comprises two pressure rollers (20, 22), the first pressure roller (20) being associated with the first deflecting roller (6) and the second pressure roller (22) being associated with the second deflecting roller (8), so as to press the sheeting (2) onto the respective deflecting rollers (6, 8).
5. Device according to claim 4, characterised in that each pressure roller (20, 22) is shiftable in the axial direction simultaneously to its corresponding deflecting roller (6, 8).
6. Device according to claim 5, characterised in that each pressure roller (20, 22) is connected to its corresponding deflecting roller (6, 8) in such a way that each pressure roller (20, 22) can be shifted in the axial direction simultaneously to its corresponding deflecting roller (6, 8) by means of the drive (14) for shifting the deflecting rollers (6, 8) in opposite axial directions.
7. Device according to claim 1, characterised in that the deflecting rollers (6, 8) are arranged adjacent to each other in a radial direction in such a way that the sheeting (2) only passes over one deflecting roller (6, 8), each deflecting roller (6, 8) having its own shaft (16).
8. Device according to claim 7, characterised in that the two shafts (16) have opposing threads and the drive (14) for shifting the deflecting rollers (6, 8) in opposite axial directions simultaneously drives the two shafts (16).
9. Device according to either claim 7 or claim 8, characterised in that the means (20, 22, 24) for changing the ratio between the friction of the sheeting (2) on the first deflecting roller (6) and the friction of the sheeting (2) on the second deflecting roller (8) comprises a pivotally mounted bearing (24) for the shafts (16).
10. Device according to claim 9, characterised in that the first deflecting roller (6) is located at a slightly greater distance from the pivot axis (26) than the second deflecting roller (8).
11. Device according to either claim 9 or claim 10, characterised in that the bearing (24) can be pivoted about an angle of between 91° and 180°, preferably about an angle of between 92° and 105°, and more preferably about an angle of between 93° and 98°.
12. Device according to any one of the preceding claims, characterised in that it comprises at least one sensor (18) for detecting the end positions of the travel of each deflecting roller (6, 8), wherein the sensor (18) is connected to the control device.

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