Format holding device

Abstract

The invention relates to a device for holding a fibrous web (1), in particular a paper web, cardboard web or tissue web or the leading and / or trailing edge of a fibrous web (1), the device having at least two holding elements (3, 4) which are arranged opposite one another with respect to the fibrous web (1) and extend transversely to the web travel direction (2), wherein at least one holding element can be moved perpendicular to the fibrous web (1) by an actuator (5). A compact and lightweight design is achieved in that at least one of the mutually opposed holding elements (3, 4) has at least one controllable pressure body (6) which is supported on the holding element (3, 4) and is directed towards the fibrous web (1), and the mutually opposed holding elements (3, 4) have magnetic elements (7, 8) which pull the mutually opposed holding elements (3, 4) towards one another.

Description

[0001] The present invention relates to a device for holding the leading end and / or the trailing end of a fibrous web, in particular a paper web, a cardboard web or a tissue web or a fibrous web, said device having at least two holding elements which are opposed to one another with respect to the fibrous web and extend transversely to the web travel direction, wherein at least one holding element each can be supported so as to be movable perpendicular to the fibrous web by an actuator.

[0002] The present invention also relates to the use of such a device and to a method for holding the leading end and / or the trailing end of a fibrous web, in particular a paper web, a cardboard web or a tissue web or a fibrous web, by means of such a device.

[0003] In unwinding devices for rolls made of fibrous webs, in particular paper, cardboard or tissue webs, splicing devices are known which connect the trailing end of the output fibrous web to the leading end of a new roll. When unwinding heavier paper rolls, the unwinding device and the subsequent processing machine are usually stopped for splicing. The heavier paper rolls are wound on continuous metal shafts (drum shafts) and can have a weight of more than 50 t when the web width is 10 m or greater.

[0004] A device is known from document EP 0 462 157 B1 which has a device for disconnecting and holding the output web. The holding device for the output web is pivotally supported in order to press the web against a replaced full roll, on the leading end of which a bonding strip is arranged. A connection is thereby established in which the trailing end of the output web overlaps the leading end of the new roll at the splicing position.

[0005] Such a device is known from document DE 43 25 944 A1. The device has a holding device for holding the trailing end of the output web, which holding device is fixedly arranged at one web side of the output web and has two holding elements which are arranged at a distance from one another in the web travel direction. A web transport device serves to pick up the leading end of the full roll at its circumference and to transport the leading end until behind the area of the holding device. In order to disconnect the web, a cutting knife is arranged in a groove between the two holding elements of the holding device. A glue strip dispenser which can be moved up and down is arranged on the other web side, by means of which glue strip dispenser an adhesive connection strip can be moved towards the web.

[0006] When the pressure element moves towards the holding element, the trailing end of the output web and the leading end of the new web are cut off together. The trailing end of the new web and the leading end of the new web are thereby directly adjacent and can thus be connected to one another without gaps.

[0007] This connection, called docking splicing, does not overlap the two webs. The advantage is that the connection location does not have twice the web thickness and does not produce a stepped step (joint) at the splicing location. Joints at the splicing location can cause interference in subsequent processing machines.

[0008] Disadvantageously, here, a very large clamping force is borne by the crossbeam, which guides the force flow through the machine in a very unfavorable way.

[0009] In addition, these holding devices mostly require a large amount of space and are relatively heavy.

[0010] Therefore, the technical problem to be solved by the present invention is to achieve a compact and lightweight web holding device.

[0011] This technical problem of the present invention is solved in that at least one of the mutually opposed holding elements has at least one controllable pressure body supported on the holding element and directed towards the fibrous web, and the mutually opposed holding elements have magnetic force elements that pull the mutually opposed holding elements together.

[0012] The clamping and holding of the fibrous web is mainly, preferably only, based on the magnetic attraction of the mutually opposed magnetic force elements.

[0013] Due to the small thickness of the fibrous web and thus the small distance between the holding elements, the action of the magnetic force elements of the holding elements on the fibrous web located between the holding elements is relatively large.

[0014] To insert the fibrous web, the actuator guides the corresponding holding element towards the fibrous web. Then, the mutually opposed holding elements are pressed against each other for clamping the fibrous web by their magnetic force elements, wherein the pressure body does not generate pressure between the fibrous web and the corresponding holding element and is preferably pressure-free.

[0015] In this clamping, the force flow directly passes through the fibrous web, so no external reaction force is generated on the surrounding components.

[0016] To release the fibrous web, first, the magnetic force elements of the mutually opposed holding elements are pushed apart from each other by the pressure body until the magnetic attraction between these force elements is small enough. A favorable force flow is also formed here.

[0017] Then, these holding elements can then be moved apart from each other by the actuator with a small force.

[0018] For a lightweight and simple structure, the mutually opposed magnetic force elements are each composed of a pair of permanent magnets or a permanent magnet and a magnetizable mating element.

[0019] If two permanent magnets are arranged opposite one another, they must be arranged in such a way as to produce a magnetic attractive force, i.e., unlike magnetic poles are arranged opposite one another.

[0020] The magnetizable mating element is a ferromagnetic material such as iron, or a ferrimagnetic material such as ferrite.

[0021] The permanent magnet exerts an attractive force on these materials.

[0022] In all cases, the magnetic attraction increases disproportionately as the distance between the magnetic force elements decreases.

[0023] In order to achieve a very simple structure in the holding element, in particular a structure in the form of a strip made of steel extending transversely to the web travel direction, the opposing holding elements should have a pressure body and a permanent magnet as magnetic force elements.

[0024] The function of the pressure body is to increase the distance between the fiber web and the corresponding holding element by forming pressure when required. In principle, electric, pneumatic or hydraulic actuators can be used here.

[0025] However, with regard to the pressure distribution across the web width, it has proven advantageous to design the pressure body as a deformable pressure hose extending transversely to the web travel direction, the cavity of which can be loaded with a pressure fluid such as compressed air or water.

[0026] For the design of guiding the corresponding holding element onto the fiber web and guiding the corresponding holding element away from the fiber web, it is advantageous for the corresponding holding element, in particular the holding element equipped with a pressure body, to be fixed to at least one lever pivotable towards the fiber web.

[0027] The actuator should also act on this lever.

[0028] In order to produce a favorable force ratio on the longer lever arm of the pressure body, the magnetic force elements should be arranged between the pressure body and the pivot axis of the lever here.

[0029] Generally, in order to minimize costs, it is advantageous for only one holding element to be supported movably perpendicular to the fiber web by an actuator, and it preferably also has a pressure body and a permanent magnet. The opposing holding element can thus be designed as a fixed strip or the like.

[0030] However, there are also applications in which it is necessary to support two opposing holding elements movably perpendicular to the fiber web by actuators respectively.

[0031] A simple design consists in that at least one, preferably two, holding elements extend over the entire width of the fiber web. This advantageously also applies to its pressure body and magnetic force elements.

[0032] However, simplifying the manufacture and installation of the holding elements is that a plurality of holding elements are arranged side by side transversely to the web travel direction, at least on one side and advantageously on both sides of the fibrous web.

[0033] However, in order to be able to design the pressure body, in particular the pressure hose, over the entire web width here, adjacent holding elements should be mechanically coupled to each other with a small gap. This prevents shear forces on the pressure body between adjacent holding elements.

[0034] In addition, the gap between the coupled holding elements also allows for manufacturing tolerances and thermal length variations.

[0035] Particularly advantageously, the holding device is used to connect the web end of the output fibrous web to the web head of the new reel when the fibrous web, in particular a paper, cardboard or tissue web, is unwound.

[0036] In particular, in so-called butt splicing devices, usually two initially uncut fibrous webs are placed one above the other and held by the device before and after the splicing position.

[0037] This means that there are two holding elements spaced apart from each other in the web travel direction on both sides of one fibrous web or on both sides of two fibrous webs.

[0038] It has proven advantageous in terms of the force flow here that the fibrous web travels vertically between holding elements that are opposed to each other and / or spaced apart from each other in the web travel direction.

[0039] The invention is further explained below based on embodiments. In the drawings:

[0040] Figures 1 to 3 shows a schematic cross-section of the holding device in different operating states;

[0041] Figure 4 shows a partial view of the holding element; and

[0042] Figure 5 shows Figure 4 an enlarged view of the partial view of

[0043] The invention is particularly suitable for unwinding devices for paper reels that are wound on a continuous metal shaft called a shaft drum and can have a weight of more than 50 t when the web width is 10 m or greater.

[0044] Here, the reel is rotatably supported at both shaft ends by its shaft drum. The fibrous web 1 is pulled from the reel and guided to a subsequent slitting and winding machine, where the fibrous web 1 is longitudinally divided into individual webs here and wound into smaller reels.

[0045] The splicing device is arranged at a distance behind the unwinding device and outside the diameter area of the full reel, and the fiber web 1 is guided through the splicing device.

[0046] When changing the reel, the trailing end of the output web is connected to the leading end of the new reel without joints, that is, the two webs are not overlapped, in a so-called butt splicing by the splicing device.

[0047] The splicing device includes one or two web holding devices that are spaced apart from each other in the web travel direction 2 and are fixedly arranged as basic components. The web holding devices each have at least two opposing holding elements 3, 4, and the fiber web 1 is guided vertically from top to bottom between the holding devices. Figure 1 It is guided vertically from top to bottom between the holding devices.

[0048] The splicing device usually also includes a web transport device as an additional element. Through the web transport device, the leading end or the trailing end of the web can be picked up and transported to the area of the holding device.

[0049] In the area of the web holding device, a known web cutting and tape application device is usually arranged. The web cutting and tape application device cuts the trailing ends of the web and connects them to each other without overlap.

[0050] If the reel is unwound until there is a remaining roll, the unwinding process is first stopped. The stationary fiber web 1 can thus be clamped by the holding elements 3, 4 of the holding device. Figure 2 of the holding elements 3, 4.

[0051] On one side, the holding device includes a holding element 3 in the form of a steel strip that extends over the entire width of the fiber web 1.

[0052] As Figure 4 shown, on the opposite side with respect to the fiber web 1, there are a plurality of holding elements 4. The plurality of holding elements 4 are arranged side by side transversely to the web travel direction 2. These short holding elements 4 are also composed of strips that extend transversely to the web travel direction 2.

[0053] The simply designed holding element 3 that extends over the entire width of the web is fixed, while the holding elements 4 arranged side by side on the other side of the fiber web 1 can be moved substantially perpendicular to the fiber web 1 and away from the fiber web 1 by pivotable levers 9.

[0054] To be able to control this movement, these levers 9 are respectively coupled to actuators 5 in the form of controllable, for example, cylinder or spindle lifting elements.

[0055] To clamp the fiber web 1 between the opposing holding elements 3, 4, these holding elements have magnetic elements 7, 8 that pull these holding elements 3, 4 together.

[0056] While the magnetic element 7 is designed as the magnetizable mating element itself from a steel strip when the holding element 3 is fixed, the opposing, pivotable holding element 4 has a plurality of magnetic elements 8 in the form of permanent magnets distributed over the web width.

[0057] Furthermore, a controllable pressure body 6 extending transversely to the web running direction 2 and over the entire width of the fibrous web 1 is attached to the pivotable holding element 4 , which pressure body is supported on the holding element 4 and can generate a pressing force in the direction of the fibrous web 1 .

[0058] For this purpose, the pressure body 6 is designed as a deformable pressure hose, the cavity of which can be acted upon by a pressure fluid, for example compressed air or water.

[0059] In order to prevent shear forces from occurring between adjacent holding elements 4 and acting on the pressure hose, adjacent holding elements 3, 4 are mechanically connected with a small gap by a pressure switch according to the invention. Figure 4 and Figure 5 The followers 11 are coupled to each other.

[0060] In order to clamp the fibrous web 1, the actuator 5 is used to clamp the fibrous web 1. Figure 2 The mutually opposed holding elements 3, 4 are guided together when the pressure element 6 is pressure-free. The actual pressing of the holding elements 3, 4 is achieved here by the opposing magnetically attractive force elements 7, 8.

[0061] In order to release the fibrous web 1, the magnetic element 8 is first pressed away from the fibrous web 1 and thus also from the opposing holding element 3 by applying pressure fluid to the pressure body 6, as shown in FIG. Figure 3 shown.

[0062] As a result, only relatively small magnetic attractive forces remain between the opposing holding elements 3, 4. The pivotable holding element 4 can then be moved further away from the fibrous web 1 by the actuator 5 with little force.

[0063] In order to optimize the effect of the pressure body 6 here, the magnetic element 8 is located between the pressure body 6 and the pivot axis 10 of the lever 9 .

Claims

1. A device for holding a fiber web (1) or the head end and / or the tail end of the web of a fiber web (1), the device having at least two holding elements (3, 4) which are opposed to one another with respect to the fiber web (1) and extend transversely to the web travel direction (2), wherein at least one holding element can be moved perpendicular to the fiber web (1) by an actuator (5). Characterized in that at least one of the mutually opposed holding elements (3, 4) has at least one controllable pressure body (6) supported on the holding element (3, 4) and directed towards the fiber web (1), and the mutually opposed holding elements (3, 4) have magnetic force elements (7, 8) which pull the mutually opposed holding elements (3, 4) together.

2. The device according to claim 1, Characterized in that the mutually opposed magnetic force elements (7, 8) each consist of a pair of permanent magnets or a permanent magnet and a magnetizable mating element.

3. The device according to claim 1 or 2, Characterized in that the holding element (3, 4) having the pressure body (6) has a permanent magnet as the magnetic force element (7, 8).

4. The device according to claim 1 or 2, Characterized in that the pressure body (6) is designed as a deformable pressure hose extending transversely to the web travel direction (2), the cavity of which pressure hose can be loaded with pressure fluid.

5. The device according to claim 1 or 2, Characterized in that the holding element (3, 4) having the pressure body (6) is fixed to at least one lever (9) which can pivot towards the fiber web (1).

6. The device according to claim 5, Characterized in that the lever (9) is coupled to the actuator (5).

7. The device according to claim 5, Characterized in that the magnetic force elements (7, 8) are arranged between the pressure body (6) and the pivot axis (10) of the lever (9).

8. The device according to claim 1 or 2, Characterized in that the two mutually opposed holding elements (3, 4) are each movably supported perpendicular to the fiber web (1) by an actuator (5).

9. The device according to claim 1 or 2, Characterized in that only one holding element (3, 4) is movably supported perpendicular to the fiber web (1) by an actuator (5).

10. The device according to claim 1 or 2, Characterized in that at least one holding element (3, 4) extends over the entire width of the fiber web (1).

11. The device according to claim 1 or 2, Characterized in that at least on one side of the fiber web (1), a plurality of holding elements (3, 4) are arranged side by side transversely to the web travel direction (2).

12. The device according to claim 11, Characterized in that adjacent holding elements (3, 4) are mechanically coupled to one another with a gap.

13. The device according to claim 1, Characterized in that the fiber web (1) is a paper web, a cardboard web or a paper towel web.

14. A method for holding a fibrous web (1) or the leading edge and / or trailing edge of the web of a fibrous web by means of a device according to one of the preceding claims, characterized in that, in order to clamp the fibrous web (1), the mutually opposing holding elements (3, 4) are guided together by an actuator (5) when the pressure body (6) is not under pressure, and in order to release the fibrous web (1), first the pressure body (6) presses the magnetic elements (7, 8) of the mutually opposing holding elements (3, 4) apart from each other, and then the holding elements (3, 4) are moved apart from each other by the actuator (5).

15. Use of a device according to one of claims 1 to 13 for connecting the trailing edge of the output fibrous web (1) to the leading edge of a new reel when unrolling the fibrous web (1).

16. The use according to claim 15, characterized in that, two mutually spaced holding elements (3, 4) in the web travel direction (2) are provided on each side of the fibrous web (1).

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