EP2485974B1 - Device for cutting paper webs - Google Patents

Description

The present invention relates generally to a device for cutting paper webs, in particular a longitudinal and transverse cutting device and in particular a device in the buffer area in front of the cross-cutting device, where the paper web or the paper webs are cut longitudinally and prepared for a cyclic feed and a trigger assembly for the controlled withdrawal of the cut paper in the region of the cross-cutting device.

Cutting devices have been known for some time. They are mainly used for the cutting of printed paper webs required by larger companies in the services sector, such as the financial or insurance sectors and administrations. These are high-performance paper processing equipment, which u.a. Include power cutting devices and are designed to operate as automated as possible.

To ensure safe operation at such high flow rates and speeds, various precautions must be taken. For example, the quiet and safe guidance of the paper web is of central importance. Another problem arises in the paper feed for the cutting device: In order to make a secure and for all purposes high-quality paper cross-separation, which should in particular have no crack marks, the paper web must and be stopped for a short moment at the cross-separation. It follows that the paper web is moved at the speed of the cross-cutting device at different speeds, or passes through different phases of the movement. In addition to a phase of constant speed, which can be as short as possible in practical operation, phases of acceleration as well as a deceleration phase to standstill are required. This results in an average speed which corresponds to the speed of the paper feed and which constitutes the operating speed of the continuously operating device.

Since these high-performance cutters should work as continuously as possible and without interruption, measures must be taken, after which the paper web is dammed in a certain area of the processing line or the cutting device (braking or holding phase) to reduce the accumulated material after the cross separation during an acceleration phase and to go back to the normal movement (constant speed). It must be ensured that, in particular, the type of acceleration does not lead to tearing of the paper web.

Out DE 100 11 006 For example, there is known an apparatus for cutting paper webs with a paper delay device operated by a blower, in which the paper web is guided through an upwardly directed loop by means of an air flow acting from the underside of the web.

On this just described principle is also based in EP 1 268 329 respectively. WO 01/66448 described web delay, in a device for cutting paper webs. Next describes the EP 1 741 653 in that first the paper web is cut longitudinally and then the two separate webs are fed via a respective large, loosely hanging loop of the cross-cutting device. In this device is due to the relatively large loop the risk of uncontrolled paper guide and thus the tilting and crumpling.

The closest state of the art is the device and method EP 1 798 176 A1 to watch.

Equally important in this context is that in the subsequent cross-cutting device, the paper webs are stopped only very briefly for the cutting process, that is, the cross cutting process must be done as quickly as possible, so it does not come in unnecessary unnecessary and oversized paper jam in the supply.

It is thus a first object of the invention to provide a device in which the coupling of the at least approximately continuous operation in the paper feed with the discontinuous operation in the cross-cutting device is such that no slipping, crumpling or even tearing of the paper web takes place. It is also important that by the longitudinal separation of the paper web and thus the merge of the two partial webs, the resulting different feed of the partial webs is compensated.

Another object of the present invention is to break the discontinuities in the discontinuous part In the case of the cross-separation means to keep as short as possible and thus to accelerate the withdrawal of the cut paper.

According to the present invention, a device for cutting paper webs with a largely continuously operated region of the paper feed and a discontinuous region of the transverse separation of the paper web according to the wording according to claim 1 is accordingly proposed.

It is proposed that the buffer area optionally provided after the longitudinal cutting between the continuous and discontinuous region, for coupling the continuous and discontinuous region, has at least one upwardly open, box-like container into which the paper web or webs are guided in a looped manner.

In the container, a negative pressure can be generated, such that the paper web is driven or pulled into the container and optionally against the side walls.

But it is also possible that in the region of the opening a fan is provided to drive the paper web in the container.

According to a variant embodiment, the buffer area is arranged according to a longitudinal cutting device, in which at least two longitudinal webs are produced, whereby at least two separate and adjacent webs are guided in the container, or the two webs are guided in two containers arranged next to one another. By placing the buffer area after a longitudinal separator, the problem is taken into account, that two partial webs are guided by means of possibly different feed to the cross-cutting device. Thus, a better buffering between continuous and discontinuous operation of the separated moving webs is guaranteed.

Again, according to a further embodiment, it is proposed to provide a separating device, such as a separating diaphragm, centrally between the loops of the paper webs, in order to prevent centering of the loops in the center.

If the container or containers have a U-shaped cross-section, for example, suction openings or a suction fan in the bottom of the container for generating a negative pressure may be arranged to pull the paper webs down. But it is also possible to provide further in the side walls of the container suction elements to pull the paper webs against the side walls.

In the event that, for example, three or more longitudinal webs are produced, the paper webs thus produced can be correspondingly looped into a container, pulled, or it can be arranged side by side or offset side by side corresponding to three or more containers to the respective paper webs for the compensation to pull into the container.

According to a further embodiment variant of the present invention, it is proposed to provide a so-called braking zone following the buffer zone or the containers mentioned above, for example by passing along a negative pressure is generated below the paper webs leaving the container or containers in order to prevent uncontrolled paper movement. Since the paper webs leaving the buffer zone are briefly stopped and accelerated again in the region of the transverse cutting, there is a risk of so-called overshoot on exiting the paper webs from the vacuum box described above, which can lead to bulging or tearing of the paper webs. For this reason, it is proposed according to the invention to provide, for example each subsequent to the so-called vacuum box in the swept through the paper webs surface suction holes, by means of which below the paper web, a negative pressure can be generated. The generated negative pressure is control-coupled with the transverse cutting process or the transport rollers upstream of the transverse cutting process, so that a braking effect is generated when the transport or during the paper delay, by means of the negative pressure. When paper acceleration, the negative pressure is released, so that the braking effect is eliminated and can be accelerated with little force and low rail load.

In the area of the cross-cutting device, a further measure according to the invention is proposed in order to optimally guide the one or other or both paper webs into the region of the transverse separation, to increase the cutting accuracy and to remove the cut papers from the cutting region as quickly as possible and without traces of abrasion. In this case, it is proposed that a transport device arranged downstream of the transverse cutting device is controllable such that it is at least temporarily can be deactivated when feeding the paper web by one of the cross-cutting device upstream transport device is deactivated, so that the paper web without resistance in the region of the transverse separation can be inserted. At or shortly after or just before the cross-cutting operation, this subsequent conveyor is activated to carry away the cut paper. It may, for example, be two rollers or rollers engaged for transport, one roller or roller being movable away from the other during insertion of the paper web and driven against the other roller or roller at or shortly before or shortly before transverse separation ,

Preferably, the transverse separation by means of a cutting element which has two cutting edges, such that with each movement of the cutting element, that is, upwards or downwards, a transverse separation of the paper web can be effected. Reference is made to the WO 2004/018167 , in which such a cross-cutting device is described, which is also part of the present invention in combination with the proposed measures according to the invention.

Finally, it is proposed in the area between buffer area and transverse separation to provide an assembly device, comprising inclined sliding tubes in order to arrange the at least two parallel, previously longitudinally separated paper webs running one above the other. The sliding tubes are preferably equipped with blown air to smear or stick together the Paper webs to prevent further preferred embodiments of the inventive device are characterized in dependent claims.

Further proposed is a method for cutting paper webs according to the wording of claim 11. Further variants of the inventive method are characterized in further dependent claims.

The invention will now be explained in more detail by way of example and with reference to the accompanying drawings.

• Fig. 1 schematisch im Längsschnitt eine erfindungsgemässe Vorrichtung zum Längs- und Quertrennen von Papierbahnen,
• Fig. 2 die Anlage aus Figur 1 schematisch in Obendraufsicht,
• Fig. 3a im Schnitt und schematisch den Pufferbereich der Anlage aus Figur 1,
• Fig. 3b in Perspektive den Pufferbereich der Anlage aus Fig. 1
• Fig. 4 in Perspektive die Bremsvorrichtung anschliessend an den Pufferbereich, und
• Fig. 5 auszugsweise schematisch und im Schnitt den Bereich der Quertrennung der Anlage aus Figur 1.

Showing:

• Fig. 1 schematically in longitudinal section an inventive device for longitudinal and transverse cutting of paper webs,
• Fig. 2 the plant off FIG. 1 schematically in a top view,
• Fig. 3a in section and schematically the buffer area of the plant FIG. 1 .
• Fig. 3b in perspective the buffer area of the plant Fig. 1
• Fig. 4 in perspective, the braking device then to the buffer area, and
• Fig. 5 in extracts, schematically and in section the area of the transverse separation of the plant FIG. 1 ,

FIG. 1 shows in longitudinal section schematically a plant for cutting paper webs both in the longitudinal and in the transverse direction. The paper web 3 is at almost continuous speed one or two lanes from a stack or withdrawn from a roll in the cutting unit 1. The inlet can be equipped with a manual cross-section knife to facilitate feeding.

The reading zone 7 is arranged directly after the inlet and is designed to be short for reading, preferably from above and from below over the entire width of the form. For a few rare exceptions, however, it is possible to provide a start / stop operation at reduced power in the reading zone.

The paper web is pulled by means of the reading zone 7 subsequent central drive 9 through the inlet and the reading zone. The drive is controlled so that the most uniform web run is achieved depending on control information, preferably from the reading (or number of sheets in applications without reading), drive the subsequent knife, application specifications such as form height, speed, acceleration ramps, loop length, etc.

Subsequent to the drive, the central section is made by means of a so-called central cutting knife 11. The web is pushed through the central cutting knife and the separated in the middle tracks are further fed to the buffer zone 15, as the in FIG. 1 Whether it works with suction, for example with a suction fan in the bottom 17 from below or with injection of air from above, is in each case to optimize due to the given conditions.

An important point of the present invention is the novel arrangement of the generated by the central section separate loops for the coupling of the continuous operation in paper feed with the discontinuous operation in the subsequent cross-separation and simultaneous solution to the problem of merging the two sub-webs in 2-up operation with different feed of the partial webs.

Instead of a single vacuum container 12, it is of course also possible to provide two containers arranged side by side, which can also be arranged offset to one another in the installation longitudinal direction.

• Kompensation Start-/Stoppbetrieb an der nachfolgenden Quertrennung zum nahezu kontinuierlichen Betrieb am Eingang
• Kompensation eines unterschiedlichen Vorschubs der beiden getrennten Teilbahnen aufgrund unterschiedlichen Vorschubs nur der einen oder anderen Bahn bei nicht gemeinsamem Schnitt.

In contrast to the prior art, the buffer region 15 is arranged below the central section, that is, in the vacuum box 12, the two webs are already separated and the two loops 3 'and 3 "arranged side by side, resulting in a double function in the vacuum box:

• Compensation Start / stop operation at the following cross separation for almost continuous operation at the input
• Compensation of a different feed of the two separate partial webs due to different feed only one or the other web in non-common cut.

Thus, the two loops of the two partial webs may have a different length. Both partial loops are at the inlet and outlet in the same plane.

In FIG. 3a is fragmentary schematic and shown in detail the buffer area 15 in detail. FIG. 3b shows the buffer area 15 in perspective. Here, alternatively, by means of a blower 24 by blowing in the air from above, analogous results can be achieved as by suction from below, for example by means of suction fan through corresponding openings 18th

The vacuum box 12 may have a vertical baffle 22 in the middle to prevent attachment of the two loops in the middle. Whether this actually leads to two separate vacuum trays, or this separating plate only in the upper region, for example in two parts with angle parts 22 ', is present, can be varied depending on requirements and operation.

Subsequent to the buffer area 15, the two paper webs 3 'and 3 "are guided over a so-called controlled braking area 21 as in perspective FIG. 4 shown. By means of this, a so-called overshoot of the paper webs to be prevented when they are stopped in the subsequently arranged cross-cutting each for a short moment. For example, it is possible to provide suction holes 26 in the contact surface formed by the paper webs 3 'and 3 ", as shown schematically in FIG FIG. 4 shown. Thus, if the two paper webs 3 'and 3 "or in each case only one of them are arranged by the transport devices 24, which are subsequently arranged in a so-called merger unit 23 respectively. 25 stopped in order to accomplish a transverse separation of one or both paper webs, at the same time a deceleration of the respective paper web by generating a negative pressure. The great advantage of the deceleration proposed according to the invention lies, on the one hand, in the fact that the paper web is not bulged during braking, and no normally used brake elements such as brushes, rollers and the like can lead to toner smearing of the printed paper webs. Also, the braking effect can be canceled quickly in the paper acceleration to prevent cracking while the paper delay maximum braking effect occurs.

As already mentioned, a so-called merger unit 23 is provided next to the braking region 21, in which the two paper webs 3 'and 3 "are guided one over the other at different levels, for example by means of inclined sliding tubes In order to avoid smearing, these sliding tubes of the merger unit 23 are equipped, for example, with blown air FIG. 1 clearly. This different height is needed to make room for the two subsequent drives 24 and 25. The merger unit is adjustable for one-way, logical and illogical. In the single-track case, the tube axes run transversely to the belt direction.

The two partial webs 3 'and 3 "converge from their two planes to as short a transport path as possible to the cross-cutting device The two transverse drives 24 and 25 run in start-stop mode The subsequent transverse separation can be effected, for example, by means of a conventional cutting element Cutting element having two cutting edges, so that both in downward movement as well as in upward movement of the cutting element, a cutting operation can be performed. Please refer to the international application WO 2004/018167 in which such an advantageous cutting element is described in detail. The content of this patent application is hereby part of the present invention and, in combination with the measures according to the invention for solving the stated problem, likewise claims the invention.

Another inventive measure is described with reference to FIG. 5 explained in more detail here by the area of the cross-separation is shown in detail and in detail. When feeding either the paper web 3 'or 3 "or at the same time both paper webs, this is done by means of the drives 24 and 25, which lead the respective paper web in the region of the transverse separating unit 27. During forward transport of the paper webs, the transport device 29, which is arranged below the transverse separation, is deactivated in this respect When, for example, a guide roller or guide roller 41 away from the drive roller or drive roller 43 is arranged in position 1, so that the paper web without resistance through the resulting gap can be pushed. Only shortly before or during the cutting process or at or shortly after the end of the cutting process by means of, for example, a cutting knife 27, the guide roller or roller 41 is driven against the drive roller or roller 43 in position 2, whereby the now cut paper 31 is transported away. However, the mode of operation of the transport device 29 may also be such that the uncut web is transported through the take-off rollers after the cut sheet 31 has been removed. Then the take-off roller is lifted as described above, so that at least just before cutting the train can stretch without resistance. The trigger or guide roller 41 is delivered only during the cut, that is driven against the drive roller 43. But it is also possible to do so already very shortly before the cut to fix the cut sheet. In other words, synchronous operation takes place on the one hand of the transport devices 24 and 25 and on the other hand of the transport device 29 comprising the two rollers or rollers 41 and 43.

The big advantage of this type of deduction compared to the deduction devices used today is that a simpler synchronization of feed and deduction is possible, the paper webs do not have to be driven by a so-called slip between the two rollers or rollers, the cutting accuracy can be increased simultaneously several paper webs can be synchronized on a cutting mark and the system is not overdetermined by the use of multiple feeds and only one deduction.

The referring to the FIGS. 1 to 4 The plant described focuses on the so-called 2-up operation. This corresponds to today's standard. The plant described according to the invention takes into account the problems arising from the so-called 2-up operation, since it is necessary to merge two parallel webs. In contrast, for example, the 1-up processing is only a trivial special case by a single-track operation is easily possible by removing the central cutting blade and straightening the sliding tubes in the merger.

Of course, with reference to the FIGS. 1 to 4 described system also suitable for the two-channel operation provided that a two-channel input is provided. Accordingly, a second drive is required in the entrance area, for example by the existing central drive laterally offset and a second drive is arranged. Of course, 3.4 or more tracks can be performed in parallel next to each other, be it by already feeding several tracks or by one or two tracks are cut several times.

The plant, presented in FIGS. 1 to 4 , serves primarily to illustrate the present invention. Of course, the system can be configured differently or supplemented by other elements. It is also possible to modify the selected parts of the system. With regard to the present invention, it is proposed, on the one hand, to design the buffer designed according to the invention between continuous and discontinuous operation to compensate for the largely continuous propulsion with the discontinuous operation. In addition, the controlled braking following the buffer area to achieve a controlled braking of the paper webs and finally the controlled trigger or the synchronization of feed and deduction in the area of the transverse separation.

Claims (11)

1. A device for cutting paper webs, comprising a substantially continuously operated area for feeding paper, a discontinuous area for transversely separating the paper web, and a buffer area (15) for coupling the continuous and the discontinuous areas, wherein at least one upwardly open box-like container (17) is provided, into which the paper web or webs (3, 3', 21) are guided so as to be looped in a freely suspended manner, wherein the buffer area is arranged after a longitudinal cutting device (9) for producing at least two longitudinal webs (3, 3'), and wherein a controlled braking area (22) is provided after the buffer area, such that braking of the movement of the paper web or the paper webs is enabled, wherein at least two webs extending separately adjacent to each other are guided in the container, or at least two containers are arranged adjacent to each other or offset adjacent to each other in which the paper webs are guided, and wherein the two adjacently extending webs can continuously have a different length among each other in a continuously alternating fashion in order to simultaneously compensate potentially different forward feed of only one partial web or both partial webs, characterized in that means for generating a negative pressure are provided in the controlled braking area (22) in the region beneath the paper webs, such that braking of the movement of the paper web or paper webs or a renewed acceleration of the paper web(s) by cancelling the negative pressure are enabled.
2. A device according to claim 1, characterized in that a negative pressure can be generated in the container, such that the paper webs are drawn or pulled into the container and optionally against the side walls.
3. A device according to one of the claims 1 or 2, characterized in that a fan is provided in order to drive the paper webs into the container.
4. A device according to one of the claims 1 to 3, characterized in that a separating device (22) such as a separating baffle is introduced into the container from above centrally in the loop of the web or webs in order to prevent attachment of the loops in the middle.
5. A device according to one of the claims 1 to 4, characterized in that suction elements (18) are provided in the side walls (12).
6. A device according to one of the claims 1 to 5, characterized in that openings are provided in the surface of the cutting device or system covered by the paper webs, in which a negative pressure can be produced for example by means of a fan.
7. A device for cutting paper webs according to one of the claims 1 to 6, characterized in that in the region of the transverse separation at least one transport device (24, 25) upstream of the transverse separating device (27) is movably coupled or synchronised with a further transport device (29) provided downstream of the transverse separating device (27), such that the further transport device, during forward feed by the upstream transport device, is deactivated at least temporarily and is activated only shortly before, during or directly after the occurred transverse separation in order to lead the cut paper away from the transverse separation.
8. A device according to claim 7, characterized in that the further transport device consists of at least two transport rollers or cylinders (41, 43), wherein the one roller or cylinder (41) is positioned during deactivation remote from the other roller or cylinder (43) in order to allow a paper web to be guided through at least temporarily without resistance.
9. A device according to one of the claims 1 to 8, characterized in that the transverse separation occurs by means of at least one cutting element having at least two cutting edges, such that during each movement of the cutting element a transverse separation of the paper web occurs, e.g. during a pendulum movement such as upwardly or downwardly.
10. A method for cutting paper webs, wherein the paper web is supplied and advanced at least substantially continuously in order to be introduced subsequently discontinuously into a transverse separating device, wherein the continuously advanced paper webs are looped after longitudinal separation through at least one upwardly open box-like container (17) in order to compensate the subsequent discontinuous processing in the transverse separating device by enlarging or reducing the loop(s), wherein the webs are driven by means of negative pressure into the container from below and/or into the container by blowing from above, characterized in that the paper webs leaving the container are braked due to processing in the subsequent discontinuous area of the transverse separating device by means of negative pressure, and the braking effect is lifted by cancelling the negative pressure in order to enable an acceleration and further transport of the paper webs.
11. A method for cutting paper webs according to claim 10, wherein the paper web is supplied and advanced at least substantially continuously in order to be introduced subsequently in a discontinuous manner into a transverse separating device, characterized in that during the feed of the paper webs to the transverse separating device a transport device provided after the transverse separating device is deactivated in such a way that the feed of the paper webs can occur substantially free from resistance.

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