EP2969873A1

EP2969873A1 - Device for separating a tubular web

Info

Publication number: EP2969873A1
Application number: EP14702789.0A
Authority: EP
Inventors: Werner Beckonert
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 2013-03-11
Filing date: 2014-01-29
Publication date: 2016-01-20
Anticipated expiration: 2034-01-29
Also published as: DE102013102414A1; US10882204B2; US20160031113A1; CN105164037B; EP2969873B1; CN105164037A; WO2014139722A1; DE102013102414B4

Abstract

The invention relates to a device (10) for separating a tubular web (11) into two flat webs (12, 13), having an adjustable blade (20) for cutting the tubular web (11), and having a pulling device (30), which acts on the blade (20) applying a tensile force (K) on a folding edge (14) of the tubular web (11). The pulling device (30) is configured such that subject to the tube properties of the tubular web (11), the tensile force (K) can be adjusted, and that while the tube properties are constant, the tensile force (K) can essentially be held constant regardless of the tube width of the tubular web (11).

Description

Device for separating a tubular web

Description

The invention relates to a device for separating a tubular web into two flat webs.

Devices for separating tubular webs in each case two flat webs are known in the production of tubular webs of plastic film by blow molding. The film is produced in the form of a tubular web and laid flat for removal. This forms two layers, which must be separated for further processing. Conventional devices for separating tubular webs in flat webs have for this purpose an adjustable knife, which is directed to a folded edge of the tubular web. Depending on the job, plastic films of different widths and properties are required, and in the course of one and the same order, differences in hose width and hose properties can occur result. There is a need that the knife is acted upon by a suitable tensile force for cutting a particular tubular web, and that the knife achieved as straight as possible regardless of the hose width. In order to position the knife against the folded edge, devices with a torsion spring are known, which can engage with a clamped rope on the knife and can press the knife against the folded edge. In these devices, however, has proved to be a disadvantage that the tensile force on the blade can not be adjusted by a torsion spring. Furthermore, it may prove to be a disadvantage that the tensile force on the blade changes during unwinding and winding of the torsion spring of the drum and is in part subject to hysteresis. If the knife is pressed more than necessary against the folded edge, it may happen that the film is damaged or even torn. If the pulling force on the knife is too low, it can happen that the knife does not hit the folded edge exactly and the flat webs are not cut straight. Moreover, it is disadvantageous in the devices of the type mentioned that a data storage from the order to the job is not possible, and that the desired tensile force can not be reproduced.

The invention is therefore based on the object to provide an improved device for separating a tubular web in two flat webs, which overcomes the disadvantages mentioned above and allows an accurate parting line of the flat webs. In particular, the device should be able to set and reproduce an optimal tensile force on the knife. The object of the present invention is achieved by all features of claim 1. In the dependent claims possible embodiments of the invention are described.

The invention provides a device for separating a tubular web into two flat webs, which is equipped with an adjustable knife for cutting the tubular web, and with a pulling device which acts on the knife with a pulling force on a folded edge of the tubular web, wherein the pulling device designed in such a way is that the tensile force is adjustable depending on the hose properties of the tubular web, and that the tensile force at constant hose properties is substantially constant regardless of the hose width of the tubular web. Under the hose properties are according to the invention, the hose thickness and hose hardness. On the one hand, certain tube properties, such as the tube thickness or hose hardness, are desired during the production of the film. For any particular order, the invention can allow to adjust the tensile force, ie to set a suitable tensile force on the knife, which is optimally suitable for cutting a tubular web with certain hose properties. On the other hand, it can happen in the production of the tubular film made of plastic film that both the hose width and the hose properties can vary during an order. Then it can happen that the tube web is not cut straight or not at all. All this leads to production delay and mis-production. In order to overcome these problems, the invention proposes to compensate for fluctuations in hose properties by means of adjustment and variations in hose width by maintaining the pulling force on the knife. Thus, if the thickness or the hardness of the tubular web varies with the same hose width, according to the invention, the tensile force must be adjusted according to the knife to better cut through the thicker or thinner, harder or more elastic tubular web. However, if the tube width becomes larger with constant tube properties, then according to the invention the tensile force on the knife must be kept constant in order to achieve an optimum cutting result. Thus it can be achieved that the tubular web is cut by means of one and the same device from the order to the order with a suitable tensile force and during an order as straight as possible in two flat paths.

The device according to the invention thus provides a traction device in which the tensile force is easily adjustable depending on the hose properties and remains as constant as possible when changing the hose width. By adjusting the pulling force on the knife, the invention ensures that the knife actually cuts through the tubular web, that the tubular web does not tear and does not get tangled on the knife. By keeping the tensile force at constant hose properties, the invention allows the knife to be positioned optimally with respect to the folded edge of the hose to counteract the changes in hose width when the web is running. This has the advantage that the tubular webs of different properties and different widths are cut with a straight cut into two flat webs. The production results can thus be improved, the production waste can be reduced and the Performance of the production of flat sheets of plastic film can be significantly improved.

According to the invention, the pulling device is equipped with a pneumatic cylinder, which can serve to set and / or hold the pulling force on the knife. Advantageously, the pneumatic cylinder allows a stepless and thus a very fine adjustment of the tensile force on the knife. The tubular web acts on the knife depending on the thickness and / or the hardness of the tubular web with a variable force, which is opposite to the tensile force by the pulling device. Due to the compressibility of the compressed air in the pneumatic cylinder, an elastic and yielding adjustment of the tensile force on the knife can be achieved. For a new order for changes in the hose properties and within one and the same order in the event of fluctuations in the hose properties, only the pressure level in the pneumatic cylinder has to be adapted for this purpose. The pneumatic cylinder thus ensures that the device according to the invention can be used flexibly for different orders for tubular webs with different properties.

In addition, the pneumatic cylinder is particularly suitable to quickly compensate for changes in the hose width with constant hose properties within a job. As the hose width changes, the pulling force on the blade changes. The knife is in mechanical operative connection with the pneumatic cylinder such that when the pulling force on the blade changes, the pressure in the pneumatic cylinder also changes. By supplying or discharging compressed air, the pressure level in the pneumatic cylinder can be quickly adjusted to restore the desired pressure in the pneumatic cylinder and thus obtain the desired tensile force on the knife. Advantageously, only the pressure level in the pneumatic cylinder must be maintained in order to realize an optimum, as constant as possible tensile force on the blade and thus optimal cutting regardless of the hose width. The pneumatic cylinder according to the invention is advantageously low-friction and allows a powerless holding the knife with a constant hose width and constant hose properties. Alternatively, it can be provided that instead of the pneumatic cylinder, a hydraulic drive or an electric drive can be used. Advantageously, the traction device according to the invention may comprise a translation mechanism to transmit the action of the pneumatic cylinder to the knife. Thus, it can be ensured that the tensile force on the knife can be adjusted even finer, while at the same time relatively large displacement paths of the blade can be realized. In addition, the forces exerted by the webs of different widths on the knife, can be intercepted even faster. The translation mechanism advantageously ensures that the tensile force on the knife is yielding and is not subject to large fluctuations, so that the tube web is not damaged even when changing the hose width.

According to the invention, the pneumatic cylinder can be connected by means of a first pull cable to the transmission mechanism, wherein the transmission mechanism can be connected by means of a second pull cable with the knife. Advantageously, the first and second cables can be made of a solid material which is non-stretchable and has no hysteresis. Thus it can be achieved that the tensile force can be optimally stored and accurately reproduced by adjusting the appropriate pressure in the pneumatic cylinder. In addition, it is advantageous that the tensile force can be provided with a linear characteristic as a function of pressure, so that the tensile force can be set very precisely.

In this case, the translation mechanism in the form of a hub with a first roll of tape on which the first pull rope is wound, and with a second roll of tape on which the second pull rope is wound, be formed. Advantageously, the first tape roll may have a diameter that is smaller than the diameter of the second tape roll. According to the invention, an optimum transmission ratio can thus be achieved, so that the possible adjustment path of the blade can be increased by the factor by which the diameter of the second belt roll exceeds the diameter of the first belt roll compared to the stroke of the pneumatic cylinder. The tensile force on the second traction cable can again be smaller by the same factor than the force on the first traction cable. Thus, with a relatively small commercially available pneumatic cylinder, relatively small tensile forces on the slitting knife and at the same time large displacement paths of the knife be enabled. The device thus provides a simple and inexpensive solution to significantly improve the cutting result.

The translation mechanism according to the invention may advantageously be rotatably mounted on a housing of the device. The translation mechanism can be mounted on a simple pivot and thus be very easy to assemble. In addition, the device may be provided a first deflection roller for aligning the first traction cable and a second deflection roller for aligning the second traction cable perpendicular to the running direction of the tubular web. Advantageously, the first traction cable can be aligned parallel to the pneumatic cylinder and be attached directly to the piston of the pneumatic cylinder. The translation mechanism can thus optimally transfer the tensile forces between the pneumatic cylinder and the knife by the deflection rollers.

According to the invention, the tubular web can be guided over a deflection roller to the knife, which can be aligned substantially perpendicular to the running direction of the tubular web. According to a particular advantage of the invention, the two flat webs can be performed after cutting the tubular web to two separate winding devices and wound there.

The knife according to the invention can advantageously be arranged movably on a guide rail by means of a sliding element. Here, the guide rail may be arranged substantially perpendicular to the running direction of the tubular web. Thus, the knife can be adjusted perpendicular to the running direction of the tubular web to better cut the tubular web of different widths and thicknesses according to the invention. The knife may advantageously have an elongated extension parallel to the running direction of the tubular web, in order to allow optimal cutting along the folded edge.

Furthermore, it can be essential to the invention that the pneumatic cylinder can be arranged on the guide rail. This can be ensured that the tensile force can be optimally transmitted to the knife. Alternatively, it is also conceivable that the pneumatic cylinder can be arranged on the housing of the device. In both Alternatively, the pneumatic cylinder may be located outside the hose so that the compressed air connections and the pneumatic cylinder are freely accessible for possible maintenance or control while the web is running.

Furthermore, it can be provided according to the invention that the blade can have at least one, in particular two blade elements. Advantageously, on the one hand, the second knife element can serve as an additional security that the material with a greater thickness or with a greater hardness can actually be severed. On the other hand, the second knife element can ensure that one of the knife elements is always ready to cut the tube web while the web is running, even if the other knife element has to be replaced or repaired.

The knife element can be inventively designed as a circular blade shear blade or the like. The circular blade shear blade can advantageously have a rotating circular disk for guiding the tubular web and a blade for cutting the tubular web. Advantageously, the circular disc can be positioned within the tubular web, wherein the cutting blade can be fastened outside the tubular web. Thus, it can be ensured that the blade can be easily accessible outside of the tube web and can be replaced with the tube running. The material of the tube web can be inserted for cutting between the rotating circular disc and the cutting blade. In this case, the circular disc can roll on the blade, wherein the material can be pressed through the circular disc to the sharp blade to cut through the intermediate tubular web.

Advantageously, the traction device according to the invention, in particular the pneumatic cylinder can be controlled automatically when the hose properties and / or the hose width changes. For monitoring the hose properties corresponding sensors can be provided. To detect that the hose width changes, the pressure in the pneumatic cylinder can be monitored. Advantageously, the first traction cable, which connects the traction device with the pneumatic cylinder, be attached directly to the piston of the pneumatic cylinder. As the tubing width becomes larger, the tubing forces the knife and the force with a decreasing force, with the pulls the first pull cable on the piston loosens therefore. The pressure in the pneumatic cylinder then drops and it can serve as a sign for switching on the traction device, in particular the pneumatic cylinder. Then compressed air can be introduced on the piston side of the pneumatic cylinder, the piston rod is thereby drawn into the pneumatic cylinder, the first pull cable stretches again and is unwound from the small roll of tape, while the turntable rotates in the direction of the pneumatic cylinder. In this case, the second pull rope is wound on the large roll of tape and the second pull rope then pulls the knife against the fold edge of the widening tubular web. If the hose width becomes smaller during production, the knife will be moved inwards through the hose path alone. The second pull rope is unwound from the large roll of tape and the turntable is turned towards the knife. The first pull rope is wound up on the small reel and the piston rod is pulled out of the pneumatic cylinder. The pressure in the pneumatic cylinder increases. In this case, the compressed air can be discharged from the pneumatic cylinder by a specially controlled compressed air connection until the desired pressure in the cylinder is reached again, which corresponds to an optimal tensile force on the knife. Optimum pressure in the cylinder can remain constant while maintaining hose properties, whereas optimum pressure can change as hose properties such as hose thickness or hose hardness change. The device according to the invention can provide sensors which monitor the hose properties and can detect the changes in the hose properties, on the basis of which new values for the optimum pressure in the pneumatic cylinder and for the tensile force on the blade can be calculated.

According to the invention, the pressure in the pneumatic cylinder can be controlled as a function of the hose properties. The traction device may have a pressure regulator to adjust the pressure in the pneumatic cylinder by supply or discharge of compressed air or to keep constant. In addition, the pneumatic cylinder may have a compressed air connection on the piston side to supply and / or omit the compressed air. If the pressure in the pneumatic cylinder is kept constant while maintaining the same hose properties, the tensile force on the blade also remains essentially constant. According to the invention, it has been found that the cutting result is optimal if, with constant hose properties, the tensile force on the blade is set essentially constant, irrespective of the hose width. Advantageously, the traction device may have a control device for controlling the tensile force on the blade as a function of the hose properties. Furthermore, the control device may be in data communication with the sensors and / or the pressure regulator and / or the compressed air connection. Advantageously, the pulling device can automatically control the tensile force on the knife. According to the invention, the control device can adjust the tensile force on the blade depending on the hose properties, such as hose thickness and / or hose hardness, and with constant hose properties, the control device can also keep the tensile force on the blade constant. For this purpose, the control device can adjust the pressure in the pneumatic cylinder by compressed air supply or -auslass or keep constant.

Advantageously, the knife can be adjusted by the pulling device when the hose width of the tubular web is larger. However, if the tube width of the tube web is smaller, so the knife can be adjusted alone through the tube web. Advantageously, then the pulling device can only adjust the knife in one direction, so that flexible tension cables can be used, which only have to be stretched in one direction. In addition, the pneumatic cylinder can then be used with only one piston-side compressed air connection. Thereby, the control and the structure of the device according to the invention can be simplified.

Further advantages, features and details of the invention will become apparent from the following description in which several embodiments are described in detail with reference to the drawings. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination. Show it:

Fig. 1 is a schematic representation of a conventional device, and

Fig. 2 is a schematic representation of a device according to the invention.

FIG. 1 shows a device for separating a tubular web 1 1 into two flat webs 12, 13, as known from the prior art. This device is with a equipped adjustable knife 20, which is directed to a folded edge 14 of the tubular web 1 1. The knife 20 can be moved along a guide rail 23 which extends perpendicular to the running direction of the tubular web 1 1. When the tube web 1 1 is wider, the knife 20 should be moved to the left. When the tube web 1 1 becomes narrower, the knife 20 should be moved to the right to hit the folded edge 14. For this purpose, the device from FIG. 1 merely provides for the blade 20 to be acted upon with respect to the outside of the tubular web 11, to the left in the image. In this case, the device has a pulling device 30 with a cable drum 31 and a traction cable I, which is guided to the knife 20 via a deflection roller 41. The pull rope I remains always clamped and pushes the knife 20 to the left. However, there is the disadvantage that the tensile force on the knife 20 by the cable drum 31 during unwinding and winding of the hawser I of the drum 31 changes and also subject to hysteresis. In addition, the tensile force can not be adjusted selectively, let alone that the tensile force changes because of the characteristics of the cable drum 31. In addition, it is disadvantageous that from the order to the order storage of the data is not possible, with which tensile force in which tubing properties of the optimal cut can be achieved.

2 shows the device 10 according to the invention for separating a tubular web 1 1 in two flat sheets 12, 13, which has an adjustable blade 20 for cutting the tubular web 1 1 and a pulling device 30, the knife 20 with an adjustable tensile force K on a folded edge 14 of the tubular web 1 1 applied, the tensile force K can be adjusted according to the hose properties. The traction device 30 according to the invention is designed such that the tensile force K remains substantially constant with the hose properties remaining independent of the hose width of the tubular web 11. It is essential to the invention that the knife 20 as possible with a finely adjusted tensile force K respect. The folded edge 14 of the tube 1 1 is positioned to achieve a straight line between the flat sheets 12, 13 and to avoid a false production when the tube web 1 1 is not properly separated or even torn.

According to the invention, the pulling device 30 has a pneumatic cylinder 33 which serves to set and / or hold the pulling force K on the knife 20. By means of the pneumatic cylinder 33, the tensile force K on the knife 20 in dependence on the Hose properties are continuously adjusted or maintained. In addition, can be optimally intercepted by the pneumatic cylinder 33, the force exerted by the tubular web 1 1 itself on the knife 20. In this case, the knife 20 can be adjusted so far until the tensile force K again has an optimal strength for cutting the film. By refilling or venting the compressed air in the pneumatic cylinder 33, the tensile force K on the blade 20 can also be kept almost constant with constant hose properties. If the widening tubular web 1 1 acts on the knife 20 with a decreasing force, the compressed air can be introduced into the pneumatic cylinder 33 in order to increase the pull on the knife 20 against the force of the tubular web 11 until the knife 20 reaches the position has reached, in which the tensile force K corresponds to a desired value. The tubular web 1 1 can thus be cut straight regardless of their width with a suitable, almost constant tensile force K. The material of the tubular web 1 1 is thereby spared as possible and the flat webs 12, 13 get a straight line as possible. The pneumatic cylinder 33 can be used for different jobs. For each new order or, if changes in the hose sheet properties occur within a job, the pressure level in the pneumatic cylinder 33 can be adjusted by supply and discharge of compressed air, which corresponds to an optimal tensile force K on the knife 20, which leads to a straight cut as possible. The pneumatic cylinder 33 can be controlled quickly, so that changes in the tube thickness or hose hardness and the hose width can be intercepted during an order. The pneumatic cylinder 33 according to the invention has low friction losses, requires little energy for driving and also allows a powerless holding the blade 20 at a constant tensile force K, hose width and hose properties. Instead of the pneumatic cylinder 33 may alternatively be used a hydraulic drive or an electric drive.

The traction device 30 according to the invention further comprises a transmission mechanism 31, 32, which transmits the action of the pneumatic cylinder 33 to the knife 20 with a translation factor D / d. The translation mechanism 31, 32 is in the form of a turntable 31, 32 with a first tape roll 31 on which a first traction cable I is wound, and with a second tape roll 32, on which a second traction cable II is wound up, formed. The first strip roll 31 in this case has a diameter d which is smaller than the diameter D of the second roll of tape 32. Advantageously, thus a Gear ratio D / d can be achieved, which increases the possible displacement of the blade 20 in comparison to the stroke of the pneumatic cylinder 33 by a factor D / d.

The pneumatic cylinder 33 is connected by means of the first traction cable I with the first tape roll 31, wherein the second tape roll 32 is connected by means of the second traction cable II with the knife 20. The first I and second traction cables II can be made of a strong, non-stretchable material so that hysteresis effects can be avoided. The tensile force K on the second traction cable II can be reduced by the factor d / D by the transmission mechanism 31, 32, as the force on the first traction cable I. Therefore, relatively small, fine tensile forces on the slitting blade 20 can be achieved while the displacement of the knife 20th can be increased to a guide rail 23. For this purpose, the knife 20 may have a slide, not shown, to be moved along the guide rail 23 perpendicular to the direction L of the tubular web 1 1. Advantageously, a very fine tensile force K can be set on the knife 20, wherein the knife 20 can still be adjusted relatively far on the guide rail 23. Thus, the forces that exert the tubular webs 1 1 different widths on the knife 20 can be intercepted faster and finer. The translation mechanism 31, 32 together with the pneumatic cylinder 33 allow a resilient retention of the tensile force K in response to changing the hose width, so that the tubular web 1 1 is not damaged.

The traction device 30 according to the invention also makes it possible to determine and store the optimum traction force K for the different hose properties. This optimal tensile force K can also be accurately reproduced by adjusting the appropriate pressure in the pneumatic cylinder 33. Thus, for different jobs, the optimum tensile force K can be recorded in order to be stored as a recipe depending on the hose properties, such as hose thickness and / or hardness. In addition, the tensile force K in the context of an order, depending on the width of the tubular web 1 1 by controlling the pressure in the pneumatic cylinder 33 are kept as constant as possible. Therefore, changes in the hose properties and the hose width can be intercepted from job to job and also during an order quickly, selectively and elastically. Advantageously, the tensile force K has a linear characteristic as a function of the pressure in the pneumatic cylinder 33, so that the tensile force K can be set very precisely and easily. The translation mechanism 31, 32 is according to the invention rotatably mounted on a housing 40 of the device 10. The device 10 further comprises a first deflection roller 41, which serves for aligning the first traction cable I in a line with the pneumatic cylinder 33, and a second deflection roller 42, which serves for aligning the second traction cable II perpendicular to the knife 20 and parallel to the guide rail 23. Advantageously, the first traction cable I is attached directly to the piston of the pneumatic cylinder 33. The translation mechanism 31, 32 can thus be transmitted by the pulleys 31, 32 and the traction cables I, II, the tensile forces between the pneumatic cylinder 33 and the knife 20. According to the invention the tubular web 1 1 is guided over a deflection roller 15 to the knife 20, which is aligned perpendicular to the running direction L of the tubular web 1 1 and parallel to the guide rail 23. The tubular web 1 1 can be performed, for example, after manufacture via the guide roller 15 for cutting to the device 10 according to the invention. Further, it is conceivable that the two flat sheets 12, 13 are performed after separating the layers of the tubular web 1 1 to two separate winding devices.

The knife 20 has, according to an advantageous embodiment of the invention, two blade elements 21, 22. Two knife elements 21, 22 advantageously serve to ensure that, when the web is running, one of the knife elements 21, 22 is always ready to cut the tubular web 11, even if the other knife element 21, 22 must be replaced or repaired. The knife elements 21, 22 according to the invention are designed as circular blade shear blades 21, 22. Each circular blade shear blade 21, 22 comprises a rotating circular disc 24, 35 for guiding the tubular web 1 1 and a blade 26, 27 for cutting the tubular web 1 1. The circular discs 24, 25 are positioned so that the tubular web 1 1 before the Cutting from the outside encloses, with the cutting blades 26, 27 remain outside the tube web 1 1. The blades 26, 27, which represent a wearing part, can be freely positioned outside of the tubular web 1 1 and replaced when needed while the web is running. The other knife element 21, 22 with the permanent blade 26, 27 can continue to be used for cutting the tubular web 1 1, even while the other blade 26, 27 is replaced. The material of the tubular web 1 1 is for cutting between the rotating discs 24, 25 and the cutting blades 26, 27 introduced. In this case, the circular disks 24, 25 on the blades 26, 27 roll off, wherein the tubular web 1 1 through the discs 24, 25 pressed against the sharp blades 26, 27 and cut as in a pair of scissors.

Advantageously, the traction device 30 or the pneumatic cylinder 33 according to the invention can be controlled automatically as a function of the hose properties and the hose width. If the hose properties remain constant, the change in pressure in the pneumatic cylinder 33 may be an indication that the hose width is changing. For controlling the pulling device 30, the pressure in the pneumatic cylinder 33 can be monitored. When the hose width becomes larger and the piston is pulled out of the pneumatic cylinder 33 with a decreasing force, the pressure in the pneumatic cylinder 33 decreases. This is an indication that the hose width becomes larger and that the pulling device 30 or the pneumatic cylinder 33 is turned on must become. The pneumatic cylinder 33 has a compressed air connection 34 on the piston side, through which compressed air can be introduced into the pneumatic cylinder 33. The piston rod 36 is then retracted into the pneumatic cylinder 33, the first traction cable I spans again. The first pull rope I is unwound from the small roll of tape 31 and the small roll of tape 31 is rotated together with the turntable 31, 32 to the right. As a result, the train is reinforced on the second pull rope II, the second pull rope II is wound on the large roll of tape 32 and the knife 20 is moved to the left. The compressed air supply is then turned off again when the desired pressure in the pneumatic cylinder 33 is reached, which corresponds to the optimum tensile force K for the tubular web 1 1 with the special properties of the current order. Thus, the tensile force K on the blade 20, even while the tube web 1 1 is wider, are kept almost constant. If the hose width becomes smaller during production, the blade 20 is itself moved to the right through the tubular web 1 1. In this case, the second pull rope II is unwound from the large roll of tape 32 and the turntable 31, 32 is rotated to the left. In this case, the first traction cable I is wound on the small roll of tape 31 and the piston rod 36 is pulled out of the pneumatic cylinder 33. The pressure in the pneumatic cylinder 33 increases. Then, the compressed air is discharged from the pneumatic cylinder 33 through the compressed air port 34 until the desired pressure in the pneumatic cylinder 33 is reached again, which corresponds to an optimal tensile force K on the blade 20 for this order. For this purpose, the device 10 may have a control device, not shown, to order within the scope of an order Change the hose width by holding the pressure in the pneumatic cylinder 33 counteract automatically. The control device may be in communication with a pressure regulator 35, which is shown schematically in FIG.

For another order, in which the tubular web 1 1 is produced with other properties such as the hose thickness and hose hardness, another pressure in the pneumatic cylinder 33 and another pulling force K on the knife 20 can provide the optimum cutting result. For different orders and different tubular webs 1 1, the device 10 can store a so-called recipe, for example, in a memory of the control device. The recipe may include for which order or for which tubular webs 1 1 which pressure in the pneumatic cylinder 33 and which tensile force K on the knife 20 are optimal. In addition, the invention can provide that during an order, the hose thickness and / or hardness can be monitored by sensors, not shown, to adjust the pressure in the pneumatic cylinder 33 and thus the tensile force 20 on the knife 20 also depending on the properties of the tubular web 1 1.

In summary, the traction device 30 according to the invention allows an automatic adjustment of the tensile force K on the blade 20 as a function of the given properties of the tubular web 1 1. It may be conceivable that the differences in hose properties can be detected in case of fluctuations, so that the pressure in the pneumatic cylinder 33 and the tensile force K on the knife 20 can be adjusted while the web is running. The invention also proposes that, with constant hose properties, the pressure in the pneumatic cylinder 33 can be kept constant by supplying or discharging the compressed air independently of the hose width. Then, depending on the hose width, a suitable position of the knife 20 on the guide rail 23 can be set, in which the knife 20 for cutting the tubular web 1 1 on the tubular web 1 1 with an optimal tensile force K acts. The device 10 according to the invention in this case has a pressure regulator 35 in order to control the pressure in the pneumatic cylinder 33. If the pressure in the pneumatic cylinder 33 is kept constant with constant hose properties, the tensile force K on the blade 20 also remains substantially constant. Advantageously, an improved cutting result can thus be achieved. The invention is based on the idea that the pulling device 30, the knife 20 moves to the left when the hose width of the tube web 1 1 is greater. However, if the hose width of the tube web 1 1 is smaller, the knife 20 is moved by the tube web 1 1 alone to the right. The pneumatic cylinder 33 also allows depending on hose properties a very fine adjustment of the tensile force K, with which the knife 20 can act on the tubular web 1 1, so as not to tear the tubular web 1 1. The translation mechanism 31, 32 ensures that at the same time the knife 20 can be adjusted relatively far to the left and right on the guide rail 23 in order to cut the tube webs 1 1 different widths. Advantageously, the device 10 according to the invention has simple components, is inexpensive and uncomplicated in construction.

Reference numeral l device

tube train

flat track

Folded edge of the tubular web

Pulley knife

first knife element

second knife element

guide rail

first round disc

second round disc

first blade

second blade pulling device

Translation mechanism / hub

first tape roll

second tape roll

pneumatic cylinder

Compressed air connection

pressure regulator

Piston rod housing

first pulley

second deflection roller I first pull rope

II second pull rope

L direction of the tube web

K traction

Claims

P atent claims

1 . Device (10) for separating a tubular web (1 1) into two flat webs (12, 13).

an adjustable knife (20) for cutting the tubular web (1 1),

and with a pulling device (30) which pulls the knife (20) with a pulling force (K).

Fold edge (14) of the hose track (1 1) is acted upon,

wherein the pulling device (30) is designed such that the tensile force (K) is adjustable depending on the hose properties of the hose web (1 1), and that the tensile force (K) with constant hose properties is independent of the hose width of the hose web (1 1). Maintains constant durability.

2. Device (10) according to claim 1,

characterized,

that the pulling device (30) has a pneumatic cylinder (33) which is used to adjust and/or maintain the pulling force (K) on the knife (20).

3. Device (10) according to claim 1 or 2,

characterized,

that the pulling device (30) has a translation mechanism (31, 32) in order to transmit the effect of the pneumatic cylinder (33) to the knife (20).

4. Device (10) according to one of the preceding claims,

characterized,

that the pneumatic cylinder (33) is connected to the translation mechanism (31, 32) by means of a first pull rope (I), the translation mechanism (31, 32) being connected to the knife (20) by means of a second pull rope (II).

5. Device (10) according to one of the preceding claims,

characterized,

that the translation mechanism (31, 32) is designed in the form of a turntable (31, 32), with a first band roll (31), on which the first pull rope (I) is wound, and with a second band roll (32), on which the second pull rope (II) is wound up.

6. Device (10) according to one of the preceding claims,

characterized,

that the first tape roll (31) has a diameter (d) that is smaller than the diameter (D) of the second tape roll.

7. Device (10) according to one of the preceding claims,

characterized,

that the translation mechanism (31, 32) on a housing (40) of the device

(10) is rotatably attached, in particular a first deflection roller (41) for aligning the first pull rope (I) and a second deflection pulley (42) for aligning the second pull rope (II) substantially perpendicular to the running direction (L) of the tubular web

(1 1) are provided.

8. Device (10) according to one of the preceding claims,

characterized,

that the tubular web (1 1) can be guided to the knife (20) via a deflection roller (15), which is aligned essentially perpendicular to the running direction (L) of the tubular web (1 1), and that, in particular after cutting, the two flat webs (12 , 13) can be led to two separate winding devices.

9. Device (10) according to one of the preceding claims,

characterized,

that the knife (20) is movably arranged on a guide rail (23) by means of a sliding element, the guide rail (23) running essentially perpendicular to the running direction (L) of the hose track (1 1), and that in particular the pneumatic cylinder (33). the guide rail (23) is attached.

10. Device (10) according to one of the preceding claims,

characterized,

that the knife (20) has at least a first knife element (21) and in particular a second knife element (22) for cutting the tubular web (1 1).

1 1 . Device (10) according to one of the preceding claims,

characterized,

that the knife element (21, 22) is designed in the form of a round disc scissor knife, which has a rotating round disc (24, 25) for guiding the tubular web (1 1) and a blade (26, 27) for cutting the tubular web (1 1). has, in particular the round disk (24, 25) inside the hose track (1 1) and the blade (26, 27) outside the hose track (1 1) can be arranged.

12. Device (10) according to one of the preceding claims,

characterized,

in that the pulling device (30) can in particular be controlled automatically when the hose properties and/or the hose width change/changes, and in particular sensors are provided which monitor the hose web (1 1) for the hose properties.

13. Device (10) according to one of the preceding claims,

characterized,

in that the pulling device (30) has a pressure regulator (35) in order to regulate the pressure in the pneumatic cylinder (33), in particular the pneumatic cylinder (33) has a compressed air connection (34) on one piston side in order to supply and/or discharge the compressed air.

H. Device (10) according to one of the preceding claims,

characterized,

in that the pulling device (30) has a control device for controlling the pulling force (K) on the knife (20) depending on the hose properties, and in particular the control device with the sensors and/or the pressure regulator (35) and/or the compressed air connection (34 ) is in data communication.

15. Device (10) according to one of the preceding claims,

characterized,

that the knife (20) is adjustable by the pulling device (30) when the hose width of the hose web (1 1) becomes larger, and the knife (20) is adjustable by the hose web (1 1) when the hose width of the hose web (1 1 ) becomes smaller.