Cutting and Transport Device for Webs of Material

Abstract

The invention describes a cutting and transport device for material sheets (1) of paper or film, which comprise at least one cutting device (7), which cuts the material sheet traversing in the cutting or the transport device. Inventive step lies in that the cutting and transport device (22) is provided with a sheet reinforcement device (10), which reinforces the material sheet with the reinforcement material (13) at the positions which are later cut by the cutting tool (7).

Description

Cutting and transport devices for material sheets are known. They are mostly used in winding devices for such material sheets. However, it is also conceivable that such cutting and transport devices are used for cutting material sheets into smaller sheet segments and that these shorter sheet segments are subsequently processed further or stored using a method other than winding. Thereby the subsequent processing can consist of, for example, pressing, followed by separation; the subsequent storage can consist of, for example, stacking of shorter sheet segments.

In winding devices, the sheets are in general transported by means of a number of transport rollers. The sheets are delivered to the winding positions in this manner. At those winding positions, the transported sheets are winded around the winding cores till the winding cores have the desired diameter and thus store the desired quantity of the film. More modern winding devices are provided with the possibility of exchanging fully winded winding cores against empty winding cores while in operation. For that, the running material sheet must be cut in the winding device. The beginning part of the sheet of the cut out sheet must then be fixed on a new winding core. To achieve that, a wide variety of methods are known. Thus, the initial winding can take place using adhesives or adhesive strips; however, fixing of the free initial part of the sheet by means of vacuum or even electrostatic charge is also known. These methods are useful both in contact winders as well as in turret winders. In modern winders, often a reversal of the rotational direction is possible in the last transport roller through which the sheet traverses before reaching the sheet winder, and despite this reversal in the rotational direction, the cutting process and the process of the initial winding proceed without any problem. In general this type of winders are provided with transport cutting rollers. Within these transport cutting rollers a knife is provided, which reaches out beyond the peripheral area of the transport cutting roller, if the transported sheet is to be cut. The transported sheet conveyed on the peripheral surface is thus cut in this manner.

In the cutting and transport devices described above, as well as obviously also in the winding devices described above, a large variety of different types of materials are transported and cut. Thereby, some material groups have been found to be particularly difficult to cut. This is true on one hand for highly fiber-containing cellulose materials. In recent times, there have been more and more problems with the film materials. Among these film materials, the film materials, which exhibit strong stability in the direction of the traversal of the sheets, play a very special role. If these materials are cut orthogonally to the direction of the traversal of the sheet, the film frays out, leading to completely unsatisfactory outcome of the cutting, in which the end and the initial parts of the sheet fray out completely. Such types of film sheets are often produced from polypropylene or at least using polypropylene in part. These materials are often drawn out along their longitudinal direction. These types of stretching processes are well known to experts familiar with the prior art. They play a role in blow film extrusion and in the blowing of the film bubbles. In flat film extrusion, it can result in distension, for instance, due to the higher speed of the outfeed roller. However, often an especially complicated stretching is involved, in which the film is cooled or heated to a particular film temperature, and thereafter the stretching process takes place. Of special significance are the predefined conditions under which the stretching takes place. In all materials, in which a high stability of the film is achieved in the direction of the transport of the film, the fraying out described above takes place during the cutting. This fraying out leads to deterioration in the quality of the film, is obstructive for the initial winding process and thus also results in deterioration of the quality of the film roll thus produced.

Therefore the aim of the present invention is to propose a cutting device, with which a better and neater cutting result is obtained. This problem is solved in that a sheet reinforcement device is provided, which reinforces the material sheet with a reinforcing material at the positions that are later cut with the cutting tool.

Especially in fast, automatically operated cutting and transport devices for material sheets, it is of advantage, if the cutting process can proceed fully automatically. For that purpose, a steering device must be provided. With programming, it can also be possible for such a steering device to adjust the application of the reinforcement material on the running material sheet and the cutting process in such a manner that the knife, or the cutting tool, slits the material sheet exactly at the place where the reinforcement material is applied. For that, in general, the position of the reinforcement material on the sheet in the direction of the transport, or the time, at which the reinforcement material is to be applied, is registered or communicated by the steering device. Then, if the speed of the sheet between the position, where the reinforcement material is to be applied, and the position, where the cutting tool is to cut the sheet, is also known, a steering device that is programmed accordingly can steer the knife or the cutting tool in such a manner that the sheet is separated at the reinforced position. Naturally, the steering device must also know the cutting place, that is, the location within the machine, where the cutting knife is to going be actuated. As a reinforcement material, different materials come in question. Such materials are, among others, viscous materials like the extrudated material and the adhesives, or hot melt as well as material strips. The reinforcement material is preferably applied orthogonally with respect to the direction of the run of the material. Preferably material strips with self-adhesive layers should be used. In the application of the reinforcement material on a running transport sheet, it is advisable to provide an application roller. The material strips can then, for instance, be fed to this application roller. The application roller can then be guided to the running sheet and can roll along with the sheet. During this rolling process, the application roller can transfer the material strips, preferably facing with its adhesive surface, on the running sheet. As already mentioned, the features of the device described above can be integrated especially with advantage in winding devices of all types. Among such devices count the contact as well as the turret winders. More modern winders of this type comprise a so-called transport cutting roller, in which the material sheet being transported on the roller is cut by a knife, whereby the knife reaches through to the peripheral area of the roller during the cutting movement. In high-end winders, the movement of the transport cutting roller is reversible and initial winding processes can be performed in both directions of the movement of the roller. These types of winders are called “winders with reversal of the rotational direction”.

Other embodiments and details of the present invention follow from the claims as well as the objective description.

The individual figures show:

FIG. 1 Sketch of a contact winder arranged according to the invention

FIG. 2 Same sketch, whereby a new cutting and initial winding process is about to take place

FIGS. 1 and 2 show a sketch of a contact winder, whereby only the rollers and the initial winding cores involved in the transport of the sheet, an old material roll and the sheet itself are shown. For the sake of better overview, other components of the winding device are not shown here. That includes the holding devices for the roller, the machine frame and the actuators required for the movements. Such devices are known to experts familiar with the prior art, and they have been mentioned, for instance, in the patent applications DE 102 02 462, DE 102 02 687, DE 102 03 149, DE 102 02 463, DE 103 21 642, DE 103 21 599, DE 103 21 600 and DE 103 21 778.

In the figures, it is shown, how a material sheet 1 is transported along the direction of the transport z by means of a winding device. Thereby, it traverses by means of the transport rollers 2, 3, 4 and 5. For the purpose of this patent application, the last transport roller, which is passed by the material sheet before reaching the initial winding core, is the transport roller 6, which can also be technically designated as the contact roller in this case. This roller 6 is distinctly provided as the transport and cutting roller, because it comprises a knife 7. This knife 7 is so designed, that it reaches through to the external perimeter of the roller 6 during the cutting process and thereby cuts the transport sheet 1 apart. For the sake of simplicity, the devices necessary for this purpose are also not shown in this application. They have been described, for example, in the German patent applications DE 100 51 372 and GM 94 13 238. As already mentioned, the material sheet in FIG. 1 and FIG. 2, after it leaves the transport cutting roller 6, is guided onto the almost complete film roll 8 and is winded thereon further. Of special interest in context of the present invention is the application roller 10, which can move from position P1 to position P2 along the direction of the arrow 12. In position P1, the application roller 10 has no contact with the material sheet 1, and can therefore be at rest, whereby a material strip 13 can be delivered to that roller along its axial direction. This material strip 13 is exactly as long as the width of the material sheet 1. In application position P2, the application roller 10 rolls along with the material sheet 1 and transfers the material strip 13 at the envisaged position in the material sheet 1. Thereby, it is of advantage if self-adhesive material strips are used. For the same reason, a roller provided with holes for the entry and exit of air is also often employed as an application roller. As mentioned, the shown winding device also comprises a steering device, also not shown here. If the adhesive strip is supplied to the roller along the axial direction of the roller, air is often blown from the outlet holes of the roller. The strip can thus slide on an air cushion onto the roller. As soon as the strip reaches its position of the application on the application roller 10, it is practical if that application strip is fixed there. This can take place, for instance, in that the vacuum is applied in the interior of the roller so that the strip can be suctioned through the inlet or the outlet holes of the air. At the time of the application of the strip on the material sheet 1, it often serves the function of lifting off the application strip 13 from the roller by means of an air blast. Before the process of the application, it is often convenient to set the application roller 10 into motion before it comes in contact with the material sheet 1. Thereby, the circumferential velocity of the application roller 10 can be so adjusted that it corresponds to the velocity of sheet 1. As soon as the steering control of the machine recognizes the position for application on sheet 1 at the appropriate time, it can regulate the rotation of the application roller in such a manner that the application strip is delivered by the application roller at the correct point of the sheet. It is practicable, if the roller also touches the material sheet 1 at the appropriate time for the application. The shown winding device is also provided with a steering device, which is also not shown here. The steering device knows position on the sheet where the material strip is to be applied. This position on the material sheet 1 is designated by the steering device as the cutting point. The path between the position of application in the roller clearance between the application roller 10 and the cutting point in the area of the new initial winding core 9 is known to the steering device. Further, the steering device can measure the rate of traversal of the material sheet 1 between these two locations. From these two values, the steering device calculates the time of the traversal and accordingly coordinates the cutting movement of the knife 7 with the application process carried out by the application roller 10. In FIG. 1, the applied material strip is already on its way to the location of the cutting process. The material strip 13 is between the transport roller 3 and the transport roller 4. In FIG. 2, the material strip 13 is already above the knife 7 on the peripheral area of the contact roller 6. After the time indicated in FIG. 2, the contact roller 6 moves forth in the direction of the arrow 15, the material sheet 1 is cut apart by the knife 7 and winded on the new winding core 9. In course of this winding process, various other mechanisms come into play. In general, the winding process is facilitated by an air blast from the peripheral area of the contact roller 6. However, the material sheet 1 is often charged electrostatically, so that it adheres to the periphery of the new winding core 9. This type of measures that support the winding are known in the prior art, they have already been mentioned in this application and are, for instance, the subject matter of the printed publications DE 102 02 462 and U.S. Pat. No. 4,852,820. After this initial winding process, the old film roll 8 swings off from its position, while the new film roll 9 or the new winding core 9 is brought in that position.

To explain the present invention again, it is important that additional material is applied directly at the cutting point in order to reinforce it. This is especially useful in materials, which are particularly stable in the direction of the run of the transport sheet, as, for instance, is the case in stretched materials or even in heavily fiber-containing cellulose materials. Therefore, this application of the adhesive material or the reinforcement material of any sort, such as for example, an adhesive strip, in not meant for gluing for the process of the winding on the new winding core 9, but solely in order to facilitate and improve the cutting process, or improve the cuts. It was found that without such measures, certain materials cannot be cut at all, or that the cutting process is executed in such an unclean manner that the subsequent winding on a new winding core 9 is thwarted. The present invention provides the remedy there.

List of Reference Symbols
1  Material sheet
2  Transport rollers
3  Transport rollers
4  Transport rollers
5  Transport rollers
6  Last transport roller before winding/contact roller
7  Knife
8  Old roll
9  New winding core
10 Application roller
11
12 Arrow indicating the movement of the application roller
13 Application strip/Material strip
14 Arrow indicating the movement of the winding core
15 Arrow in the direction of the movement of the contact roller
16 Arrow in the direction of the movement of the old roll
17
P1 Swiveled position of the application roller
P2 Application position of the application roller
z  Direction of the transport of the film sheet 1
22 Cutting and transport device

Claims

1. Cutting and transport device for material sheets (1) of paper or film, comprising at least one cutting tool (7), which cuts the material sheet running in the cutting or transport device (22),

characterized by

a sheet reinforcement device (10), which reinforces the material sheet (1) with reinforcement material (13) at the places, which are later cut by the cutting tool (7).

2. Device according to claim 1,

characterized by

a control device, which registers the position of the reinforcement material (13) on the sheet (1) in the direction of the transport of the sheet (z) and/or the time, when the reinforcement material (13) is to be applied, as well as the velocity of the sheet between the position, where the reinforcement material is to be applied, and the position, where the cutting tool (7) cuts the sheet,

calculates on the basis of these values when the reinforcement material will pass through the area of the action by the cutting tool and regulates the cutting tool in such a manner that it cuts the sheet apart at the reinforced place.

3. Device according to claim 1,

characterized in that

the sheet reinforcement device (10) comprises the means for application of a viscous reinforcement material.

4. Device according to claim 1,

characterized in that

the sheet reinforcement device (10) comprises the means for application of a material strip (13).

5. Device according to claim 1,

characterized in that

the material reinforcement device (10) comprises an application roller (10) for the transport of the material strip (13), which can be so positioned that it can roll along with the material sheet (1) during the operation and transfer the material strip (13) on the sheet (1) during this rolling motion.

6. Method for transport and cutting of material sheets of paper or film,

in which at least one cutting tool (7) cuts a running material sheet at the cutting points,

characterized in that

a sheet reinforcement device (10) reinforces the material sheet with the reinforcement material (13) at the places, which are later to be cut by the cutting tool (7).

7. Method according to the preceding claim

characterized in that

the sheet reinforcement device (10) reinforces the material sheet (1) with the reinforcement material (13), which material strips (13) have at least one self-adhesive surface.

8. Method according to claim 6,

characterized in that

a material sheet (1) made of a plastic material is cut.

9. Method according to the preceding claim,

characterized in that

the plastic material contains polypropylene.

10. Method according to claim 8,

characterized in that

the plastic material is a stretched plastic material.

11. Device for winding running material sheets (1) on winding cores (8,9), in which full winding cores (8) are exchangeable against empty winding cores (9), and which exhibits the following characteristics:

one or more winding positions at which the winding cores (8) can be linked and can be winded with the film,

at least one cutting device with a cutting tool (7), which cuts apart the material sheet (1), if full winding cores (8) are to be exchanged against empty winding cores (9) during operation,

a winding device, which fixes the initial part of the material sheet (1) formed by the cutting process on a new winding core (9),

characterized in that

the winding device comprises a cutting and transport device (22) according to claim 1 can be employed with it.

12. Winding device according to the preceding claim,

characterized in that

the cutting device is integrated in a material transport roller (2-6).

13. Winding device according to the preceding claim,

characterized in that

the cutting device is integrated in the last material transport roller (6), which is located in the direction of the transport (z) of the material sheet (1) just before the winding core (8,9).

14. Winding device according to claim 1,

characterized in that

the winding device is embodied as a turret winding device, in which the winding process can be take place in both directions of rotation of the last material transport roller (6), which is located in the direction of transport (z) of the material sheet (1) just before the winding core (8,9).