A joint and an apparatus for connecting ends of a fibrous web

Abstract

The invention relates to a joint and an apparatus for joining ends of a fibrous web. The joint is configured to be formed by a cut which is arranged to penetrate the ends of the fibrous web in a lap position, the cut having a side portion and from the side portion extending a substantially straight portion, the cut forming a flap which is configured to remain attached to the fibrous web by attachment of a fold line. The fold line of the flap is substantially aligned with the direction of motion of the fibrous web. The apparatus comprises a tool having a cutting edge and a counter element having a recess or an opening or a resilient surface portion, the tool being located on one side of the fibrous web and the counter element being located on the other side of the fibrous web relative to the tool, wherein the recess is positioned such that when the tool penetrates the fibrous web, the tool protrudes into the recess or the opening or the resilient surface portion of the counter element. The cross-sectional area of the recess or the opening of the counter element is larger than the cross-sectional area of the tool, or the resilient surface portion of the counter element yields, providing a loose fit.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to unwinding of a fibrous web. In particular, the present invention relates to joining of fibrous web ends in a parent roll change in an unwinder, in particular in an unwinder of a slitter-winder. BACKGROUND

[0002] It is known that fibrous webs, such as paper, board or pulp fibrous webs, are manufactured in a plurality of machines that are brought together to form a fibrous web manufacturing line, the length of which can be several hundred meters. A modern paper machine can produce over 450,000 tons of paper per year. The speed of a paper machine can exceed 2000 meters / minute, and the width of a paper fibrous web can exceed 11 meters.

[0003] From the prior art it is known that in the production and processing of fibrous webs, a process typically comprises an assembly formed of a plurality of devices arranged in succession in a process line. A typical production and processing line comprises a headbox, a wire section and a press section, and subsequently a drying section and a reel-up. The production and processing line can further comprise finishing equipment, such as a calender and / or a coater. The production and processing line typically also comprises at least one slitter-winder for forming customer rolls, and roll packaging equipment.

[0004] On a fibrous web production line, the manufacturing is carried out in one continuous process run. The finished fibrous web is output from the machine and wound around a reel-up shaft, i.e. reel shaft, into a parent roll (machine roll) by a reel-up. The purpose of the winding is to change the fibrous web manufactured in a plane into a form that is easier to handle. In the reel-up, the continuous process of the machine is interrupted for the first time, and the process is changed to a periodic run.

[0005] The fibrous web wound on the parent roll is full-width, and it must be slitted into partial fibrous webs having a suitable width, and the partial fibrous webs are wound into partial fibrous web rolls (customer rolls) whose length or diameter is suitable for customer use. From the prior art it is known that the slitting and winding are carried out in a suitable separate machine, i.e. in a slitter-winder.

[0006] As is known from existing technology, in a slitting and rewinding machine, the master roll is unwound, and the full-width fiber web is slit into multiple narrower fiber web segments on the slitting section. These segments are then wound into customer rolls on the winding section around a winding core, a winding shaft, or a rewinding core located on a shaft (such as a spool). When the customer roll is complete, the slitting and rewinding machine stops, and multiple rolls (i.e., so-called sets) are removed from the machine, and the winding process for new sets continues. These stages are repeated periodically until the fiber web is used up from the master roll, at which point the master roll is replaced, where the end of the used master roll is attached to the beginning of a new master roll, and the unwinding operation of a new master roll continues, either slitting the full-width fiber web into partial fiber webs and winding them into customer rolls, or replacing the master roll by threading the beginning of a new master roll onto the rewinding machine.

[0007] As known from existing technology, regarding slitting and rewinding machines, full-width fiber webs from unwinding machines are cut into partial fiber webs by the slitting and rewinding machine. These partial fiber webs are then wound into partial fiber web rolls by a windup. The partial fiber web windup can be a support roller type windup, where the partial fiber web roll is supported by support rollers and wound through a winding pressure zone between a forming fiber web roller and a second support roller. In a support roller type windup, the second support roller can be a set of belt rollers, where an endless belt loop is arranged around the two rollers. The partial fiber web windup can also be a center-driven windup, where the partial fiber web roll rotates from the center and is wound through a pressure zone between the forming fiber web roller and the winding drum.

[0008] When the fiber web is unwound from the unwinding machine and the unwound roll is almost empty, the master roll is replaced. This is usually still done entirely manually. Related to the master roll replacement, the empty end of the master roll is attached to the end of a new, complete master roll via a connector that connects the ends of the fiber web. Connecting the ends of the fiber web is also required in relation to other unwinding machines on the fiber web production line.

[0009] In existing joints and equipment, the joining of fiber web ends is achieved using adhesives (such as glue or tape), which requires equipment to provide the adhesive in order to establish a joint between the fiber web ends. A continuous supply of adhesive is also necessary, and different types of adhesive may be required depending on the grade of the fiber web being produced. It should also be noted that, particularly when producing thick fiber webs (such as pulp fiber webs), existing joints and equipment do not provide a satisfactory solution because the joint strength at the fiber web ends is often insufficient.

[0010] From the prior art it is known to connect the ends of a fibrous web by form-fitting, i.e. mating, overlapping joints. The ends of the fibrous web, which are normally placed in an overlapping position, are punched in several positions, the flaps resulting from the punching forming the form-fitting joints. Normally the punching assembly comprises a punching blade, one blade being provided for each punching cut and a respective counter cut, the punching assembly being used to press out two different types of paired flaps at the ends of the web. The structure of the punching flaps is such that one protruding tab and its flat part are aligned with the direction of travel of the web, the other being similar but opposite to the direction of travel of the web. Thus, the flaps are opened so that the folding line of the flaps is straight from the direction of travel of the web. When the flaps are opened, the overlapping ends of the web must be moved relative to each other according to the length of the flaps before the connection takes place. In these arrangements, it is disadvantageous that each punching cut requires a corresponding counter cut. This disadvantage is even more aggravated when the web has a large width of several metres, because several separate punching cuts and counter cuts are required in the width direction to ensure the connection. This increases the cost of the equipment used in the arrangement. A further disadvantage is that these types of joints require the overlapping web ends to be moved relative to each other to ensure the connection.

[0011] In patent application publication DE4124022A1 a method for connecting the ends of a thin material is disclosed, in which different flaps penetrate the ends of the material, holding the material ends together. The punching assembly comprises a punching blade, one blade being provided for each punching cut and a respective counter cut, the punching assembly being used to press out two different types of paired flaps at the ends of the web. The structure of the punching flaps is such that one protruding tab and its flat part are aligned with the direction of travel of the material, the other being similar but opposite to the direction of travel of the material.

[0012] In patent application publication JPS624164A a method for connecting sheets is disclosed, in which U-shaped cuts are drilled in the overlapping parts of two sheets and one flap protrudes through the other cut. The sheets are moved in position so that the flaps connect with the cuts. In this method, one blade is provided for each punching cut and a respective counter cut.

[0013] The disadvantage of many known joints and equipment in the prior art is that even though their function is so good, they can be too complicated and thus costly for some of the current needs. SUMMARY

[0014] The object of the present invention is to provide a joint in which the above-mentioned disadvantages related to the connection of the ends of a fibrous web have been eliminated or at least minimised.

[0015] The object of the present invention is to create a joint and a device in which the disadvantages and problems of known joints and devices, in particular the problems of connecting the ends of the fibrous web in connection with changing the parent roll in an unwinder, are eliminated or at least minimized.

[0016] A particular object of the present invention is to create a joint and a device in connection with the joining of the ends of the pulp web in connection with changing the parent roll in an unwinder of a slitting rewinder.

[0017] According to the invention, the joint for connecting the ends of at least two fibrous webs together is configured to be formed by at least one cut, which is arranged to penetrate the ends of the fibrous webs in the overlap position, the cut having at least one side portion and from the side portion extending at least one substantially straight portion, the cut forming at least one flap, which is configured to hold attached to the fibrous web attached by at least one fold line, wherein the fold line of the flap is substantially aligned with the direction of movement of the fibrous web.

[0018] The cut can be formed by a continuous cut line, or it can also comprise one or more partial tearing lines in connection with forming the cut. Thus, the term "cut" in this context has the meaning of a continuous cut line, and the cut line comprises one or more partial cut lines and one or more partial tearing lines.

[0019] The joint for connecting the ends of at least two fibrous webs can be located on each fibrous web, at any distance, on the free run of the fibrous web ends, at the same or different distances from the free edges of the fibrous web ends.

[0020] According to the invention, the cut has a corner form in the direction of movement of the fibrous web, which is formed at the meeting place of the side portion of the cut and the fold line, configured to form a load-bearing portion of the joint.

[0021] According to an advantageous feature, the tension of the fibrous webs is configured to tighten the joint due to the tension between the fibrous webs.

[0022] According to an advantageous feature, the cut has two opposite arc-shaped or angular side portions, between which a substantially straight portion extends, and forms two flap portions on the cut, which are separated from each other by the substantially straight portion extending between the side portions and hold attached to the fibrous webs by the fold line.

[0023] According to an advantageous feature, a plurality of cuts are provided for the ends of the fibrous webs to be connected.

[0024] According to an advantageous feature, no adhesive or tape is used at the joint to connect the end portions of the fibrous web.

[0025] According to an advantageous feature, the fibrous webs are pulp webs.

[0026] According to the invention, the device for connecting end portions of fibrous webs together comprises a tool having a cutting edge configured to provide a cut to the end portions of the fibrous web, and a counter element having a recess or an opening or a resilient surface portion, the tool being located on one side of the fibrous web and the counter element being located on the other side of the fibrous web relative to the tool. Wherein the recess or the opening or the resilient surface portion is positioned such that, when the tool penetrates the fibrous web, the tool penetrates into the recess or the opening or the resilient surface portion of the counter element, wherein the cross-sectional area of the recess or the opening of the counter element is larger than the cross-sectional area of the tool, or the resilient surface portion yields, thereby providing a loose and spacy fit.

[0027] According to an advantageous feature, the device comprises a holder for holding and guiding the fibrous web.

[0028] According to an advantageous feature, the holder is connected with and movable together with the tool, or according to another advantageous feature, the holder is independently movable.

[0029] According to an advantageous feature, the counter element comprises a holding surface located opposite the holder on the other side of the fibrous web relative to the holder, the fibrous web being configured to be held between the holding surface and the holder.

[0030] According to an advantageous feature, the tool has at least one cutting edge configured to provide a cut to the end portions of the fibrous web, and at least one opening edge for opening the cut in the fibrous web.

[0031] According to an advantageous feature, the device is in a unwinder of a slitting rewinder.

[0032] According to an advantageous feature, the device is in a unwinder for pulp webs.

[0033] According to an advantageous aspect, the joint and the device are configured to connect an end of one fibrous web with an end of another fibrous web, so that the fibrous webs are connected by a form-fit joint, wherein one fibrous web can pull the other fibrous web to a desired position with a desired tension and speed. The form-fit joint provided is configured to be able to withstand any possible turns etc. in the horizontal direction perpendicular to the surface of the fibrous web, such as turns that occur when the fibrous webs and the joint are running on guide rolls etc. Furthermore, the form-fit joint is configured to be created in the shortest possible time.

[0034] According to an advantageous aspect, the connection of the ends of the fibrous web is provided by a device that brings the ends of the fibrous web into a lap position. The device comprises tools that penetrate the fibrous web in a tensioned position against counter elements or protrude against the counter elements when the fibrous web is moved in the same direction. The counter elements provide recesses or openings that are larger in area than the corresponding tools, or the counter elements provide elastic portions that yield, thus providing a loose fit. The tools are configured to penetrate the lap ends of the fibrous web in the position of the respective recesses or openings or elastic portions of the counter elements. Thus, the tools are also arranged to protrude into the respective recesses or openings or elastic portions of the counter elements. The cutting edge of the tool is configured to cut the material of the end of the fibrous web when protruding, in addition to partly opening the incision of the lap end of the fibrous web in the last phase of the protrusion. The shape of the recesses or openings of the counter elements can differ from the shape of the cutting profile of the tool. Thus, the cutting edge of the tool cuts the desired cutting profile against the counter element when penetrating the tensioned fibrous web, or in the case of thicker fibrous webs, such as pulp webs, the cutting of the tool can start near the edge of the recess or opening of the counter element to provide an additional shearing effect. The cutting effect is essentially provided by the cutting edge of the tool, and the cutting also takes advantage of the properties of the fibrous web to be cut - the fibrous web is hard and can be cut without the aid of a counter element profile that strictly corresponds to the profile of the tool. Thus, there is a great advantage in terms of tolerances and manufacturability when manufacturing the counter elements, especially in the case of a fibrous web that is very wide, requiring several joints in the width direction to provide a secure connection.

[0035] According to an advantageous aspect, the tools of the device are configured to open the incision as a result of their protruding movement, so that the one or more fold lines of the flap are essentially aligned with the direction of movement of the fibrous web. Thus, the joint is immediately kept in the direction of movement of the fibrous web without the need to move the fibrous webs relative to each other as in arrangements according to the prior art. This provides an improved method of securing the joint, since no additional movement that can disrupt the movement is needed. In addition, no special facilities are needed to move the fibrous webs when the joint is finally completed.

[0036] According to an advantageous aspect, after the joint has been completed, the fibre web is tightened to each other due to the configuration of the cut and the flaps as separate joints, and one and the other fibre web are tightened to each other due to the flaps of the joint. The flaps arranged in the direction of movement of the fibre web cause the stress of the joint mainly in the surface of the fibre web, and thus the flaps are not as susceptible to folding as in the arrangement according to the prior art, in which the flaps are susceptible to opening due to the perpendicular positioning with respect to the direction of movement of the fibre web. This is particularly important for thinner paper or board grades, which are susceptible to folding.

[0037] According to the application, the cutting edge of the tool has a configuration forming a corner configuration in the direction of movement of the fibre web, preferably a curved or barbed cut. This corner configuration is configured to combine with the lap portion when the fibre web is tightened, which improves the safety of the joint, especially when the fibre web is run on a curved run path, because it prevents the opening of the flaps, thus solidifying the curved run.

[0038] The application is applicable to different kinds of fibre webs, and it is particularly advantageous for thick fibre webs having a thickness of at least about 0.14 mm, and it is also very advantageous for the unwinding of pulp fibre webs, because now a very reliable and functional arrangement of the pulp web is provided. In particular, known joints providing a joint of sufficient strength of the adhesive or tape connection of the pulp fibre web end are not usable, because the adhesive and tape joint of the pulp web end would cause delamination of the pulp fibre web. The density of the pulp fibre web is about 400-800 kg / m 3 , and the thickness of the pulp fibre web is about 0.5-2.5 mm.

[0039] The application is very advantageous when used in connection with the unwinder of a slitting rewinder due to the sequential operation of the slitting rewinder. The application can also be used with the unwinders of other components and parts of the fibre web production line.

[0040] By means of the joint and the apparatus according to the application, many advantages can be achieved: the structure of the required apparatus is simpler than in the arrangements known in the prior art, and thus costs can be saved. No adhesive is used, and thus costs are further saved, and thus the structure can also be made simpler. The application also provides the possibility of connecting the ends of different grades of webs. In addition, a simple and robust structure of the joint apparatus is also achieved.

[0041] The exemplary embodiments of the application presented in this patent application are not to be interpreted as limiting the applicability of the application. The verb "to comprise" and its derivations are used in this patent application as an open limitation that does not exclude the existence of also unmentioned features. The features described in the following description are mutually freely combinable, unless explicitly stated otherwise. BRIEF DESCRIPTION OF DRAWINGS

[0042] However, the various aspects of the present application, including its structure and method of operation, together with additional objectives and advantages thereof, will be best understood from the following description of some exemplary embodiments when read in connection with the accompanying drawings, wherein:

[0043] FIG. 1A A side view of an advantageous example of a device providing a joint for connecting ends of a fibrous web is schematically shown, the tools of the device being in a resting position;

[0044] FIG. 1B A side view of an advantageous example of a device providing a joint for connecting ends of a fibrous web is schematically shown, the tools of the device being in a protruding position;

[0045] FIG. 2 A surface level view of an advantageous example of a device providing a joint for connecting ends of a fibrous web is schematically shown, the tools of the device being in a protruding position;

[0046] FIGS. 3A-3C A view of an advantageous example of a tool of a device providing a joint for connecting ends of a fibrous web is schematically shown;

[0047] FIGS. 4A-4B A view of an advantageous example of a joint for connecting ends of a fibrous web during formation of the joint is schematically shown;

[0048] FIGS. 5A-5B A view of an advantageous example of a joint for connecting ends of a fibrous web during lap formation of the joint is schematically shown;

[0049] FIGS. 6A-6F A view of an advantageous example of a tool of a device and a joint configuration for connecting ends of a fibrous web is schematically shown;

[0050] FIG. 7 A view of an advantageous example of a cut of a joint for connecting ends of a fibrous web is schematically shown; and

[0051] FIGS. 8A-8B A view of some variations of a recess or opening of an opposing element of a tool of a device for connecting ends of a fibrous web is schematically shown.

[0052] List of reference signs

[0053] 10: tool

[0054] 12A, 12B: holding member

[0055] 13: recess

[0056] 14: Maintain the surface

[0057] 15: The end of a fiber web

[0058] 16: The end of another fiber web

[0059] 17: Incision

[0060] 18: Fold line

[0061] 19: Cut the edge

[0062] 20: Opposing element

[0063] 21: Corner configuration

[0064] 22: Opening edge

[0065] 23: Wing section

[0066] P: Maintain pressure

[0067] S: Direction of movement of the fiber web Detailed Implementation

[0068] In the following description, numbers and symbols are used to identify similar elements according to different views illustrating the invention and its advantageous examples. In the figures, some repeated reference numerals have been omitted for clarity.

[0069] exist FIGS. 1A-1B The example shows a device comprising a tool 10 and a counter element 20 to provide a connector for attaching the ends of fiber webs 15, 16. The direction of movement S of the fiber webs 15, 16 is indicated by corresponding arrows. The device also includes retainers 12A, 12B for holding and guiding the fiber webs 15, 16. FIGS. 1A-1BIn the figure, the lower holder 12A moves with the tool 10, and the upper holder 12B does not move with the tool 10, but is independently movable. The upper holder 12B is in contact with the surface of the fibrous web 15, 16 during the joining of the ends of the fibrous web 15, 16, thus keeping and guiding the fibrous web 15, 16 throughout the joining. The lower holder 12A moves with the tool 10, thus keeping and guiding the fibrous web 15, 16 throughout the piercing of the fibrous web 15, 16. The counter element 20 of the apparatus comprises a recess 13 or similar opening for at least each tool 10. The counter element 20 can also comprise a resilient surface. The tool 10 is located on one side of the fibrous web 15, 16, and the counter element 20 is located on the other side of the fibrous web 15, 16 opposite the tool 10. The position of the recess 13 is such that when the tool 10 penetrates the fibrous web 15, 16, the tool 10 protrudes into the recess 13 or opening of the counter element 20, or the resilient surface of the counter element 20 yields when the tool 10 penetrates the fibrous web 15, 16. The counter element 20 also comprises a holding surface 14, which is located on the opposite side of the fibrous web 15, 16 opposite the holder 12A, 12B, opposite the holder 12A, 12B.

[0070] In FIG. 1A the figure, the tool 10 is in its standby position, at a distance from the fibrous web 15, 16.

[0071] In FIG. 1B the figure, the tool 10 has penetrated and pierced the fibrous web 15, 16 to reach the corresponding recess 13 of the counter element 20, providing a cut for the fibrous web 15, 16. The holders 12A, 12B keep the fibrous web 15, 16 against the corresponding holding surface 14 of the counter element 20.

[0072] FIG. 2 The fibrous web 15, 16 and the above apparatus are shown, and it can be noted that the recess 13 is spacy in view of the tool 10 providing a cut 17 to the fibrous web 15, 16.

[0073] In FIGS. 3A-3C the figure, an example of a tool 10 of an apparatus providing a joint for joining the ends of the fibrous web 15, 16 is shown, in FIGS. 4A-4BAn example of a joint for connecting fibrous webs in the formation of a joint is shown in Fig. 1. The tool 10 has at least one cutting edge 19 which forms a cut 17 in the fibrous webs 15, 16 when penetrating and piercing the fibrous webs 15, 16. The tool 10 also has at least one opening edge 22 for opening the cut 17 in the fibrous webs 15, 16 when penetrating the fibrous webs 15, 16. The penetrating end of the tool 10 is in this example formed with a tapered configuration substantially directed in the direction of penetration, such that a substantially sharp edge line is formed at the first contact portion which can be bent towards the tool 10 and from the end of the first contact portion a top sharp edge line extends away from the sharp edge line forming a plurality of curved sharp side edge lines and the opening edge 22 is arranged to extend between the curved sharp side edge lines. The tool 10 forms a cut 17 in the fibrous webs 15, 16 with a fold line 18. The cut 17 has two opposite arcuate portions corresponding to the sharp side edge lines of the tool 10 and a substantially straight portion extending between the arcuate portions corresponding to the top sharp edge line of the tool 10. The cut 17 is opened along the fold line 18 when the opening edge 22 penetrates the fibrous webs 15, 16. The cut 17 also has a corner configuration 21 which forms a load bearing portion of the joint. In this example two flap portions 23 are formed in the cut 17 which are separated from each other by the substantially straight portion extending between the arcuate portions and are held in attachment to the fibrous webs 15, 16 by the fold line 18.

[0074] From FIGS. 5A-5B It can be seen that the cut 17 forms a lap joint by the tension of the fibrous webs 15, 16 during penetration of the fibrous webs 15, 16 such that the actual cut 17 of each fibrous web 15, 16 is slightly distanced and the flap portions 23 are slightly lapped. This distance is 0.1-10 mm, preferably 0.5-2 mm, depending on the thickness of the fibrous webs to be connected.

[0075] The joint and the device are configured to connect an end of one fibrous web 15 with an end of another fibrous web 16, so that the fibrous webs 15, 16 are connected by a form-fit joint, in which one fibrous web 15, 16 pulls the other fibrous web 16, 15 with the desired tension and speed to the desired position, i.e. to the overlap position. The device comprises tools 10, against which the tensioned position of the fibrous webs 15, 16 protrudes against counter elements 20. Alternatively, the tools 10 protrude against the counter elements 20 when the fibrous webs 15, 16 are moved in the same direction. The counter elements 20 are provided with recesses 13 or openings, the area of which is larger than the corresponding tool 10. The tools 10 are configured to penetrate the overlapping ends of the fibrous webs at the location of the recesses 13 or openings of the counter elements 20. The tools 10 are thus also provided to protrude into the recesses 13 or openings of the counter elements 20. The cutting edges 19 of the tools 10 are configured to cut the material of the ends of the fibrous webs 15, 16 when penetrating, and to partly open the incision of the overlapping ends of the fibrous webs by the opening edges 22 in the last phase of the penetration. The shape of the recesses 13 or openings of the counter elements 20 can differ from the shape of the cutting profile of the tools 10. The cutting edges 19 of the tools 10 thus cut the desired cutting profile while penetrating the tensioned fibrous webs 15, 16 against the counter elements 20. The tools 10 of the device are configured to open the incision 17 as a result of their protruding movement, so that the folding line 18 of the flap 23 is essentially aligned with the movement direction S of the fibrous webs 15, 16. The joint thus remains immediately in the movement direction S of the fibrous webs 15, 16. After the joint is completed, the fibrous webs 15, 16 are tightened to each other as a result of the configuration of the flap 23 and the incision 17 as a separate joint, one and the other fibrous web 15, 16 being tightened to each other as a result of the flap 23 of the joint. The flap 23 is positioned in the movement direction S of the fibrous webs 15, 16. The cutting edges 19 of the tools 10 have a corner profile 21 formed in the movement direction S of the fibrous webs, preferably the shape of a curved or barbed incision. This corner shape 21 is configured to combine the overlapping part of the flap 23 during the tightening of the fibrous webs 15, 16.

[0076] In FIGS. 6A-6C some alternative examples of the tools 10 are shown in which the corresponding symmetrical profiled incision 17 and two flaps 23 are shown. The cutting edges 19 of the tools 10 consist of at least a top edge part and a side edge part, between which an opening part extends. The incision 17 thus has a central incision formed by the top edge part and extending between the side cut parts formed by the side edge parts of the cutting edges 19. The folding line 18 extends between the respective ends of the side cut parts and forms the flaps 23. In FIGS. 6D-6F some examples of asymmetrical incisions 17 with one flap 23 are shown. In FIG. 7Further examples of asymmetric cuts with one flap 23 are shown in the middle part of the figure, where the cuts are located in different directions one after the other, and in the lower part of the figure, where the cuts are located in different directions above and below each other.

[0077] In FIGS. 8A-8B Some examples of variations of the recesses 13 or openings 13 of the counter element 20 are shown in FIG. 8A An example of a small pitch is shown in FIG. 8B An example of a larger pitch is shown in

[0078] In the above description, although some functions have been described with reference to certain features, these functions can be performed by other features, whether described or not. Although features have been described with reference to certain embodiments or examples, these features can exist in other embodiments or examples, whether described or not. The above description of the application has only referred to some advantageous examples, and the application should not be narrowly limited thereto. Many modifications and changes can be made in the application as defined in the following claims.

Claims

1. A joint for connecting end portions of at least two fibrous webs (15, 16) together, wherein the joint is configured to be formed by at least one incision (17) provided to penetrate end portions of the fibrous webs (15, 16) in a lap position, the incision (17) having at least one side portion and from the side portion extending at least one substantially straight portion, the incision (17) forming at least one tab (23) configured to remain attached to the fibrous webs (15, 16) by attachment of at least one fold line (18), characterized in that, The folding line (18) of the flap (23) is essentially aligned with the direction of movement (S) of the fibrous web (15, 16), the cut (17) has a corner configuration (21) in the direction of movement (S) of the fibrous web (15, 16), the corner configuration being formed at the meeting place of the side of the cut and the folding line (18), configured to form a load bearing part of the joint.

2. The joint of claim 1, wherein, The tension of the fibrous web (15, 16) is configured to tighten the joint due to the tension of the fibrous web relative to each other.

3. The joint according to claim 1 or 2, characterized in that The cut (17) has two opposite arched or angular sides, between which an essentially straight part extends, and forms two flap parts on the cut (17), which are separated from each other by the essentially straight part extending between the sides and are kept attached to the fibrous web (15, 16) by the folding line (18).

4. The joint of claim 1 or 2, wherein Several cuts (17) are provided for the ends of the fibrous web (15, 16) to be connected.

5. The joint of claim 1 or 2, wherein, No adhesive or tape is used in the joint to connect the ends of the fibrous web (15, 16).

6. The joint of claim 1 or 2, wherein The fibrous web (15, 16) is a pulp web.

7. A slitter winder comprising an unwinder for unwinding a fibrous web (15, 16), the slitter winder further comprising an apparatus for joining together the ends of the fibrous web (15, 16), the apparatus comprising: A tool (10) having a cutting edge (19) is configured to provide a cut (17) for the end of the fibrous web (15, 16), and a counter element (20) having a recess (13) or an opening or a resilient surface part, the tool (10) being located on one side of the fibrous web (15, 16), the counter element (20) being located on the opposite side of the fibrous web (15, 16) relative to the tool (10), wherein the recess (13) or the opening or the resilient surface part is positioned so that when the tool (10) penetrates the fibrous web (15, 16), the tool (10) protrudes into the recess (13) or the opening or the resilient surface part of the counter element (20), characterized in that the joint according to any one of claims 1-6 can be formed by means of the slitting rewinder.

8. The slitting and rewinding machine according to claim 7, characterized in that The cross-sectional area of the recess (13) or the opening of the counter element (20) is greater than the cross-sectional area of the tool (10), or the resilient surface part of the counter element (20) yields, thereby providing a loose fit.

9. The slitting and rewinding machine according to claim 7, characterized in that, The device comprises holders (12A, 12B) for holding and guiding the fibrous web (15, 16).

10. The slitting and rewinding machine according to claim 9, characterized in that The holder (12A) is connected to the tool (10) and movable with the tool (10).

11. The slitting and rewinding machine according to claim 9, characterized in that The holder (12A) is independently movable.

12. The slitting and rewinding machine according to any one of claims 9-11, characterized in that The counter element (20) comprises a holding surface (14) opposite the holders (12A, 12B), the holding surface being on the opposite side of the fibrous web (15, 16) relative to the holders (12A, 12B), and the fibrous web (15, 16) is configured to be held between the holding surface (14) and the holders (12A, 12B).

13. The slitting and rewinding machine according to any one of claims 7-11, characterized in that, The tool (10) has at least one opening edge (22) for opening the cut (17) in the fibrous web (15, 16).

14. The slitting and rewinding machine according to any one of claims 7-11, characterized in that, The apparatus is located in a rewind machine of a slitter winder.

15. The slitting and rewinding machine according to any one of claims 7-11, characterized in that, The apparatus is located in a rewind machine for a pulp web.

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