EP4237615A1

EP4237615A1 - Web connection and paper machine fabric

Info

Publication number: EP4237615A1
Application number: EP21782708.8A
Authority: EP
Inventors: Robert Eberhardt; Torsten Wich
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2020-10-28
Filing date: 2021-09-22
Publication date: 2023-09-06
Also published as: WO2022089843A1; MX2023004917A; JP2023547453A; US20230407565A1

Abstract

The invention relates to a web connection for a fabric of a machine for producing or processing a fibrous material web, comprising a first web end with first longitudinal thread ends, a second web end with second longitudinal thread ends, and at least one connection element which extends in the transverse direction of the subsequent fabric. The invention is characterized in that the connection element has an upper face and a lower face, and the first longitudinal thread ends and the second longitudinal thread ends solely contact the upper face of the connection element and are bonded thereto, in particular the thread ends are welded thereto. The invention also relates to a fabric with a paper side and a running side. The fabric has at least one first web layer, said first web layer having at least one such web connection which is arranged such that the lower face of the at least one connection element is oriented in the direction of the running side of the fabric.

Description

Fabric connection and paper machine clothing

The invention relates to a fabric connection and a covering and a seam covering of a machine for producing or processing a fibrous web

Clothings, in particular clothings for paper machines, often comprise one or more fabric belts as a component. Endless fabric tapes, so-called tape loops, are usually required for use in a covering. These can either be woven directly as a ribbon loop ("circular woven") or they can be woven as a flat piece of fabric which is made endless by connecting the two longitudinal ends.

Various possibilities are known from the prior art for such a connection of two ends of a fabric strip.

US 2014/0186579 describes the connection of two ends by means of an ultrasonic weld seam. However, this type of connection is disadvantageous. On the one hand, as can also be seen in the figures in US 2014/0186579, the fabric suffers during the welding process. The properties of the joint after welding are not readily predictable. The strength properties of the welded filaments also suffer. This is particularly disadvantageous since adequate tensile strength, particularly in the machine direction, is an important quality feature of the base fabric and of the finished covering. Finally, such welds are also comparatively brittle.

A welded connection of two fabric ends is also proposed in US Pat. No. 7,381,307. US Pat. No. 7,381,307 does not go into great detail about welding the ends, but generally proposes laser welding as a suitable type of connection. It is an object of the present invention to propose a fabric connection that is improved over the prior art and an improved covering with such a fabric connection.

On the one hand, a solid fabric connection is to be proposed that is easy to manufacture.

It is also an object of the invention to propose a fabric connection whose properties can be easily adapted to the required application.

It is a further object to propose a fabric with a fabric connection in which the fabric connection leaves few traces on the fibrous web produced.

The objects are completely solved by a fabric connection according to claim 1 and a covering according to claim 2 and a seam covering according to claim 7.

Advantageous embodiments are described in the dependent claims.

If, in the context of this application, it is said that an element absorbs light, e.g.

When it is said in the context of this application that an element is transparent to light, eg laser light of a specific wavelength, this should be understood to mean that at most 20%, preferably at most 10%, particularly preferably at most 5% of the radiated energy is absorbed. If within the scope of this application it is said that an element has an upper side or an underside, this should be understood in the case of circular elements in such a way that the semicircle above a center line is understood as the upper side and the semicircle underneath as the underside.

The same applies, mutatis mutandis, to elliptical or similar elements.

With regard to the connection, the object is achieved by a fabric connection for a clothing of a machine for the production or processing of a fibrous web, comprising a first fabric end with first longitudinal thread ends and a second fabric end with second longitudinal thread ends, as well as at least one connecting element that extends in the transverse direction of the subsequent clothing . The invention provides that the connecting element has an upper side and a lower side, and the first longitudinal thread ends and the second longitudinal thread ends are in contact exclusively with the upper side of the connecting element and are cohesively connected to it, in particular welded.

The feature that a longitudinal thread end only touches the top of the connecting element should also be considered to be fulfilled if a small part of the longitudinal thread end touches a connecting element outside the top, for example as a result of a melting process during welding.

The machine can in particular be a paper machine (or board machine, tissue machine) or a pulp machine.

It is advantageous if the integral connection takes place by means of transmission welding, in particular laser transmission welding. This method is advantageous in the area of clothing for paper and pulp machines, among other things, because these clothings often consist entirely or partially of polyamides, and polyamides are largely transparent, for example in the NIR wavelength range. By inserting fully or partially absorbent Connecting elements can be welded very easily. In addition, the non-absorbent parts of the covering are not or only very slightly affected by the welding process.

In advantageous embodiments of the fabric connection, several connecting elements, in particular two or three connecting elements, can be provided. In this case, in particular, the first and second longitudinal thread ends can each be in contact exclusively with the upper side of the connecting elements and can be cohesively connected to them, in particular welded. By providing several connecting elements, the strength of the tissue connection can be increased on the one hand, while on the other hand—compared to using a single, larger connecting element—the flexibility and also the permeability of the tissue connection can be increased.

Provision can furthermore be made for one or more transverse threads, in particular 2-5 transverse threads, to be removed from the first fabric end and/or the second fabric end in order to produce the first longitudinal thread ends and/or the second longitudinal thread ends. This is advantageous in particular when using a plurality of connecting elements in order to produce longitudinal thread ends of sufficient length.

Advantageously, the connecting elements can extend over a plurality of longitudinal thread ends of a fabric end. As a rule, the connecting elements will extend across the entire width of the fabric in the transverse direction.

In preferred embodiments it can be provided that at least one connecting element, preferably all connecting elements, is designed as a thread. The thread or threads can in particular have a circular, oval or rectangular cross section. However, threads with other cross sections are also possible. By suitably shaping the cross-section, for example “X”-shaped, “Y”-shaped or wedge-shaped, it is also possible to use threads a single material that changes compressibility and elasticity. In addition, the contact surface of the connecting elements with the longitudinal thread ends can be increased without creating too high a material density in the fabric connection.

It is also possible that the connecting elements are not designed as a thread. Alternatively, it is also possible, for example, to design some or all of the connecting elements as fabric strips or as foils or foam strips.

Furthermore, it can be provided that the diameter of the at least one connecting element is larger, in particular more than 10%, preferably more than 30% larger, than the diameter of the woven transverse threads of the first fabric end and the second fabric end.

If several connecting elements, in particular connecting threads, are used, it can be advantageous for the distance between two adjacent connecting elements to be greater, in particular more than 10%, preferably more than 20%, than the distance between adjacent transverse threads of the first fabric end and the second fabric end.

The joining, in particular welding, of fabric ends can take place as described by removing transverse threads at the fabric ends with the formation of longitudinal thread ends protruding from the fabric ends, providing transverse threads and subsequently arranging the longitudinal thread ends over the provided transverse threads. An obvious embodiment would be to remove the same number of transverse threads from both fabric ends (e.g. 3 pieces) and to provide the same number (3 pieces) of connecting elements, in particular thread-like connecting elements in the overlapping area of the longitudinal threads, ideally at almost the same distance as the das Full fabric specifies.

In addition, it seems obvious to use transverse threads with the same diameter as the transverse threads in the fabric for the connecting elements provided. If a transmission welding method is used for the connection, the inserted/provided transverse threads can also be designed in such a way that they sufficiently absorb the light of the wavelength that is used for the welding.

However, it was found that provided connecting elements with a larger diameter compared to transverse threads in the full fabric of the fabric ends lead to more stable welded connections, which is due to the fact that the contact pressure applied when welding the fabric ends presses the longitudinal and transverse threads together better in the connection area and generally larger ones Contact surfaces are generated at the thread connections. Thanks to simultaneous pressing and welding, however, fabric connections with only minimal deviations in thickness compared to full fabric are obtained.

For example, fabric connections with a cross thread diameter of the connecting elements of 0.5 mm instead of 0.4 mm for the cross threads of the full fabric could be obtained with strengths of +30-90%. In both cases, however, the thickness of the connection zone was comparable and largely identical to the thickness of the full fabric.

A larger diameter of the connecting elements can also be advantageous if the fabric is to have a high storage volume and is therefore designed as a 1.5-layer or 2-layer fabric.

For example, in a 1.5-ply fabric, the cross-directional yarns can be so close together that they are slightly shifted up and down, resulting in a thicker and bulkier fabric. If threads with the same diameter as the transverse threads of the fabric were used as the connecting element - which is possible in principle - the fabric seam would be thinner than the rest of the fabric. This could result in unwanted markings on the paper. By using correspondingly thicker threads as connecting elements, the thickness of the fabric and fabric seam can be matched. Alternatively or additionally, it can be provided that threads of a different type are used for the connecting elements than for the transverse threads of the fabric. In particular, it can be provided that threads are used for the transverse threads of the full fabric and monofilaments for the connecting elements. This can be advantageous, since welded joints with monofilaments can usually be realized more easily and reproducibly than with twisted threads. In a preferred embodiment, threads of the type 2.times.2.times.0.2 mm are used for the transverse threads of the full fabric (2 filaments with a diameter of 0.2 mm are twisted together, and then two of the threads thus produced are twisted together again). Monofilaments with a diameter of 0.4 mm can be used for the connecting elements. In addition to this described example, however, a large number of other combinations are also possible.

In advantageous embodiments, it can be provided that the connecting elements are designed to absorb light of a wavelength in the range between 780 μm and 1200 μm, at least on their respective upper side.

In addition, it was found that such fabric connections with connecting elements which have a different distance from the distances between the transverse threads in the full fabric of the fabric ends are advantageous. If, for example, 4 transverse threads are removed at the ends of the fabric but only 3 transverse threads are provided as connecting elements for the fabric connection, which are arranged at largely the same distance in the connection area, somewhat more open fabric connections are obtained after the welding, which have a reduced material density compared to the connections described above.

In addition, the relatively rigid connection area (all longitudinal thread ends and all connection elements are ideally welded together at all contact points) is somewhat more flexible. Both effects have an advantageous effect, for example, when needling the base fabric layers with fleece fiber layers of a press felt. In very dense fabric connections, fiber transport is usually inhibited during needling. Despite the higher material density there due to the fabric connection, areas of the press felt are obtained which, after needling, have a higher permeability compared to needled areas in the full fabric. Fewer fibers are needled into the fabric layer, non-woven fibers on the paper side are sometimes transported to neighboring areas during the needling process, or lead to thick areas due to concentration above the fabric layers.

Furthermore, it can be provided that the connecting elements are deformable, in particular elastically deformable.

This can be realized in particular by the connecting elements comprising an elastomer, in particular a polyurethane.

In principle, the connecting elements can be made of a uniform material or be made up of different materials. So-called core-sheath threads, among others, can be used as connecting elements, with the core and the sheath being made of different materials. It is possible here, for example, for the connecting elements to have a core made of polyurethane, which is surrounded by a jacket made of polymer material, the jacket being designed to absorb light of a wavelength in the range between 780 μm and 1200 μm.

The jacket should be thick enough to prevent the core material from being bare during or after welding. On the other hand, it should be thick enough so that the soft or elastic core is still able to compress and expand again when the thread is loaded.

A possible alternative to the core-sheath threads are so-called "top-bottom" elements or "top-bottom" threads used as connecting elements.

Such a thread has an absorbent upper side and an underside that has good elastic properties. For example, an underside made of TPU (thermoplastic polyurethane) and a top side made of a polyamide, for example a PA6, to which an absorber additive is added. Industrial soot (“carbon black”) is very well suited as an absorber additive.

Further advantages of the ideas described here are better fiber anchoring and an improved permeability profile.

A clothing for a machine for producing or processing a fibrous web is disclosed with a paper side in contact with the web and a running side facing away from the web, the clothing comprising at least a first fabric layer which has at least one fabric connection according to one aspect of the invention described above

With regard to the clothing, the problem is solved by a clothing for a machine for producing or processing a fibrous web with a paper side in contact with the web and a running side facing away from the web, the clothing having at least one first fabric layer. The invention provides that the first fabric layer has at least one fabric connection according to one aspect of the invention described above, the fabric connection being arranged such that the underside of the at least one connecting element is directed towards the running side of the clothing.

Advantageous designs of the covering are described in the dependent claims.

A fabric layer of a covering according to an aspect of the present invention can consist, for example, of a piece of fabric which is made endless by a single fabric connection. The tissue connection then joins the two tissue ends of the same piece of tissue together. This piece of fabric can have the same fabric properties (e.g. weaving pattern, thread thickness, thread density) over its entire extent. But it is also possible that a property, e.g. the weave pattern, changes across the piece of fabric. For example, the weaving pattern can change along the longitudinal direction of the piece of fabric.

In alternative embodiments, it can be advantageous that the first fabric layer has a plurality of fabric connections that are constructed according to one of the aspects described above, with all fabric connections being arranged in particular in such a way that the underside of the respective connection elements is directed towards the running side of the clothing. The tissue connections then connect the tissue ends of different tissue pieces together.

Here, too, the individual pieces of fabric can either be identical or differ in one or more properties. In particular, the individual pieces of fabric themselves can either have the same fabric properties (e.g. weaving pattern, thread thickness, thread count) over their entire extent. However, it is also possible that a property, e.g. the weaving pattern, changes over the piece of fabric.

Furthermore, it can be advantageous if the covering has one or more further fabric layers, which can also have one or more fabric connections, in particular according to one of the aspects described above. The first fabric layer is preferably arranged closer to the paper side of the clothing than the other fabric layers.

With regard to the seam covering, the object is achieved by a seam covering for a machine for producing or processing a fibrous web, with a paper side in contact with the web and a running side facing away from the web, the seam covering comprising a basic structure that is realized by folding a piece of fabric at two fold points and under formation of a two-layer fabric is placed on itself, the two fabric ends being connected to one another by a fabric connection, and seam loops being formed at the folds, an endless fabric loop being produced by connecting the seam loops by means of a pin wire element to form a pin wire seam. According to the invention it is provided that the fabric connection is designed according to an aspect of the invention described above, and the fabric connection is arranged such that the underside of the at least one connecting element points in the direction of the interior of the resulting two-layer fabric.

Here, too, advantageous embodiments are specified in the dependent claims.

For example, provision can be made for the fabric connection to be arranged in the layer of the two-layer fabric closer to the paper side, with the underside of the connecting element being directed in the direction of the running side of the clothing.

Due to the fact that the fabric connection is arranged in the position closer to the paper side, the fabric connection does not come into direct contact with the drive, guide or dewatering elements of the paper machine during operation of the seam covering. Thus, the fabric connection is protected and wears out less. This is particularly advantageous since the integral connection--particularly when it is designed as a welded connection--can break under constant stress from these elements, especially if the drive, guide or drainage elements attack the side of the connecting element.

Such a design is therefore particularly advantageous in applications where a high risk of wear is to be expected due to the machine design or mode of operation.

Alternatively, it can be provided that the fabric connection is arranged in the layer of the two-layer fabric closer to the running side, with the underside of the connecting element being directed in the direction of the paper side of the clothing.

With this arrangement, the fabric connection is separated from the fibrous web at least by the second layer of fabric. This can significantly reduce the tendency of the tissue connection to mark. To protect the fabric connection from wear and tear, it is aligned in such a way that the connection element or elements point inwards, ie away from the drive, guide or dewatering elements of the paper machine. Such a design is particularly advantageous in applications where, due to the range of types produced, even slight markings through the seam covering lead to significant quality defects.

Alternatively or additionally, it can be provided that the covering and/or the seam covering has at least one additional fabric layer, the additional fabric layer being a circularly woven fabric layer.

In preferred embodiments, the fabric or the seam fabric can be a press felt in which the paper side of the fabric is provided by a fleece layer which is connected to the fabric layer or layers by needling.

The following sentences are used once again to describe various aspects of the invention:

set l . Fabric connection for a covering of a machine for the production or processing of a fibrous web, comprising a first fabric end with first longitudinal thread ends and a second fabric end with second longitudinal thread ends, and at least one connecting element which extends in the transverse direction of the later covering, characterized in that the connecting element has an upper side and has an underside, and the first longitudinal thread ends and the second longitudinal thread ends are in contact exclusively with the upper side of the connecting element and are cohesively connected to it, in particular welded.

Sentence 2. Tissue connection according to one of the preceding sentences, characterized in that a plurality of connecting elements, in particular two or three connecting elements, are provided, and the first longitudinal thread ends and second longitudinal thread ends each exclusively are in contact with the top of the connecting elements and are connected to them in a materially bonded manner, in particular welded.

Set 3. Tissue connection according to one of the preceding sentences, characterized in that one or more transverse threads, in particular 2 -5 transverse threads, are removed from the first fabric end and/or the second fabric end to produce the first longitudinal thread ends and/or the second longitudinal thread ends.

Sentence 4. Tissue connection according to one of the preceding sentences, characterized in that at least one connecting element, preferably all connecting elements, is designed as a thread.

Set 5. Tissue connection according to Set 4, characterized in that the thread has a circular, oval or rectangular cross-section.

Set 6. Tissue connection according to one of the preceding sentences, characterized in that the diameter of the at least one connecting element is larger, in particular more than 10%, preferably more than 30% larger than the diameter of the woven transverse threads of the first fabric end and the second fabric end.

Sentence 7. Fabric connection according to one of sentences 2 to 6, characterized in that the distance between two adjacent connecting elements is greater, in particular more than 10%, preferably more than 20% greater than the distance between adjacent transverse threads of the first fabric end and the second fabric end.

Sentence 8. Tissue connection according to one of the preceding sentences, characterized in that the connecting elements are designed to absorb light of a wavelength in the range between 780 pm and 1200 pm at least on their respective upper side. Sentence 9. Tissue connection according to one of the preceding sentences, characterized in that the connecting elements are deformable, in particular elastically deformable.

Sentence 10. Fabric connection according to one of the preceding sentences, characterized in that the connecting elements comprise an elastomer, in particular a polyurethane.

Set 11 . Tissue connection according to one of the preceding sentences, characterized in that the connecting elements have a core made of a polyurethane which is surrounded by a cladding made of polymer material, the cladding being designed to absorb light of a wavelength in the range between 780 pm and 1200 pm.

Sentence 12. Clothing for a machine for producing or processing a fibrous web with a paper side in contact with the web and a running side facing away from the web, the clothing having at least one first fabric layer, characterized in that the first fabric layer has at least one fabric connection according to one of the previous sentences, the Tissue connection can be arranged in particular so that the underside of the at least one connecting element is directed towards the running side of the clothing. (In principle, other arrangements are also possible, see e.g. FIG. 7e).

Clause 13. Clothing according to Clause 12, characterized in that the first fabric layer has a plurality of fabric connections according to one of clauses 1 to 11, all fabric connections being arranged in such a way that the underside of the respective connecting elements is directed towards the running side of the clothing.

Sentence 14. Covering according to one of sentences 12 to 13, characterized in that the covering has one or more further fabric layers which also have a fabric connection, in particular according to one of sentences 1 to 11, wherein the first fabric layer is arranged closer to the paper side of the clothing than the other fabric layers.

Set 15. Covering according to one of sets 12 to 14, characterized in that the cover has at least one additional fabric layer, the additional fabric layer being a round-woven fabric layer

Set 16. The clothing according to any one of sets 12 to 15, characterized in that it is a press felt, the paper side of the clothing being provided by a fleece layer which is connected to the fabric layer or layers by needling.

The invention is explained in more detail below with the aid of schematic figures

Figures 1a and 1b illustrate a tissue connection according to one aspect of the present invention.

FIG. 2 shows a tissue connection according to a further aspect of the invention.

FIGS. 3a to 3d show possible connecting elements according to various aspects of the invention in cross section.

FIG. 4 shows further possible cross sections for connecting elements according to various aspects of the invention.

FIG. 5 shows a fabric according to a further aspect of the invention. FIGS. 6a and 6b each show a fabric according to a further aspect of the invention

FIGS. 7a to 7e show a possible production process for a woven basic structure for a covering, in particular according to one aspect of the present invention. FIG. 1a shows a first fabric end 2a and a second fabric end 2b, which are to be connected by means of a fabric connection 1. FIG. For example, these can be two ends of a single piece of fabric, which is made endless by the fabric connection. But it can also be tissue ends 2a, 2b of two different pieces of tissue that are joined by the tissue connection 1.

The first fabric end 2a has first longitudinal thread ends 3a and the second fabric end 2b has second longitudinal thread ends 3b. In order to produce longitudinal thread ends 3a, 3b of sufficient length for the fabric connection 1, some transverse threads 6 of the full fabric were removed from both fabric ends 2a, 2b. It is often advantageous if between two and five transverse threads 6 are removed per fabric end 2a, 2b.

FIG. 1b shows how the two fabric ends 2a, 2b from FIG. 1a are brought together. Here, three connecting elements 4 are provided in the form of connecting threads 4, which run in the transverse direction of the subsequent covering.

The connecting elements 4 have a top 4a and a bottom. The first longitudinal thread ends 3a and the second longitudinal thread ends 3b are arranged in such a way that they are only in contact with the upper sides 4a of the connecting elements 4. To produce the fabric connection 1, the connecting elements 4 and 4 are connected to the upper sides 4a of the connecting elements 4 in a materially bonded manner. The integral connection can advantageously be produced by welding, in particular by (laser) transmission welding. If the longitudinal thread ends 3a, 3b are made of a polyamide, as is usual in many fabrics, they are completely or largely transparent to light in the NIR range. If at least the upper side 4a of the connecting elements 4 is designed to absorb light from this area - for example by adding a suitable absorber additive such as carbon black - then suitable NIR laser light can be used to shine through the longitudinal thread ends 3a, 3b, the absorbent upper sides 4a of the Connecting elements 4 heat up and weld to the longitudinal thread ends 3a, 3b. The process is usually carried out by applying a certain joining pressure.

Alternatively, however, the integral connection can also be realized, for example, by other welding processes such as ultrasonic welding or adhesive connections.

The fabric connection 1 shown in FIG. 2 is a special embodiment of the fabric connection 1 from FIG. 1b. The connecting elements 4 are designed in the form of connecting threads 4, which have a larger diameter compared to transverse threads 6 in the solid fabric of the fabric ends 2a, 2b. This leads to more stable welded connections, which is due to the fact that the contact pressure applied when welding the fabric ends 2a, 2b presses the longitudinal thread ends 3a, 3b and connecting elements 4 together better in the connecting area and generally larger contact surfaces are generated at the thread connections. Simultaneous pressing and welding nevertheless produces fabric connections 1 with only minimal deviations in thickness compared to full fabric.

For example, fabric connections 1 with connecting elements 4 with a diameter of 0.5 mm instead of 0.4 mm for the transverse threads 6 of the full fabric can be obtained with 30-90% increased strength. However, the thickness of connection zone 1 was comparable in both cases and largely identical to the thickness of the full fabric.

Another example is a 1.5-ply or 2-ply fabric where, for example, the cross-directional yarns are so close together that they are slightly shifted up and down, resulting in a thicker and bulkier fabric. In this way, for example, in the case of transverse threads 6 and longitudinal threads of the longitudinal thread ends 3a, 3b with a diameter of, for example, 0.4 mm each, the fabric itself can have a thickness of 1.2 mm. (The specified diameters are only to be understood as exemplary possible values. The However, the invention is not limited to these values). If threads with a diameter of 0.4 mm were also used here as connecting elements 4, the thickness of the fabric connection would be significantly smaller at approximately 0.8 mm than that of the rest of the fabric. This can lead, among other things, to undesired markings in the paper produced.

A solution here can also be the use of thicker connecting elements 4 .

With a diameter of the connecting elements of 0.8 mm, together with the diameter of the longitudinal thread ends 3a, 3b of 0.4 mm, this results in the same thickness of 1.2 mm for the fabric connection as for the fabric. As described above, the diameter of the connecting elements 6 can even be slightly larger (e.g. 10% or 20%). Simultaneous pressing and welding again produces fabric connections 1 with only minimal deviations in thickness compared to full fabric.

While this allows fabric connections 1 to be produced with the desired thicknesses, it can sometimes happen that the resulting fabric connection 1 is quite heavy but also hard due to the comparatively thick connection elements 4, and especially quite incompressible compared to full fabric. This can be countered by providing the connecting elements 4 with a certain elasticity through a suitable choice of material (e.g. using an elastomer) and/or suitable shaping of their cross sections. Advantageous examples of this are shown in FIGS. 3a-3d and 4.

In addition, in FIG. 2, the connecting elements 4 were used at a distance that is greater than the distance between the transverse threads 6 in the solid fabric of the fabric ends 2a, 2b. To produce the longitudinal thread ends 3a, 3b, four transverse threads 6 were used here as an example at the fabric ends 2a, 2b, but only 3 transverse threads were used as connecting elements 4 for the fabric connection 4. As a result, somewhat more open fabric connections 1 are obtained after the connection, which have a reduced material density. In addition, the relatively rigid connection area 1 (all longitudinal thread ends 3a, 3b and all connection elements 4 are ideally welded to one another at all contact points) is somewhat more flexible. Both effects have an advantageous effect, for example, when needling the base fabric layers with fleece fiber layers of a press felt.

In order to be able to carry out the integral connection efficiently by means of laser transmission welding, it is advantageous if the connecting elements 4 are designed to be absorbent at least on their upper side 4a. For this purpose, as already described, the entire connecting element can be designed to be absorbent by means of an absorber additive. However, it is also possible that only parts of the connecting element 4 are absorbent. FIG. 3a shows a classic core-sheath thread in which only the sheath 8 is absorbent, while there is relatively great freedom in the design of the core 7. This core can again be made of a polyamide, for example. But it is also possible to use the core 7 from other materials, e.g. B to manufacture an elastomeric polyurethane. The resulting increased elastic properties of the connecting element 4 can prove to be advantageous.

Figures 3b, 3c and 3d show variants of these connecting elements 4 made of mixed materials.

“Half-and-half threads 4 can be seen in FIGS. 3b and 3c—one with a round cross section and one with a rectangular cross section. Here, the upper part, e.g. the upper half, is made of absorbent shell material 8, and the lower part is made of non-absorbent core material 7.

FIG. 3d shows a variant of FIG. 3c. Here, in the case of a rectangular connecting element 4, only the surface of the upper side 4a is made of absorbent material 8. This can be applied to the connecting element before welding, for example. Suitable materials are commercially available, for example, under the name "Clearweld". The connecting elements 4 shown here are only intended to show the variety of possibilities. The invention is not limited to these examples.

FIG. 4 shows further possible cross sections for connecting elements 4 according to various aspects of the invention. With a suitable shape, for example in the form of an “X”, a “Y” or a wedge, the compressibility and elasticity can be changed even with threads made of a single material. In addition, the contact surface of the connecting elements with the longitudinal thread ends can be increased without creating too high a material density in the fabric connection.

Alternatively, however, connecting elements 4 shaped in this way, as shown in FIG.

FIG. 5 shows a covering 10 according to a further aspect of the invention. The covering 10 is designed as a press felt. It comprises a fleece layer 13 which makes the paper side 11 of the covering 10 available. The fleece layer 13 is arranged on a first fabric layer 14 and fixed, for example, by needling. The first fabric layer 14 has a fabric connection 1 which connects a first fabric end 2a with first longitudinal thread ends 3a and a second fabric end 2b with second longitudinal thread ends 3b to one another. For this purpose, three connecting elements 4 are provided in the covering 10 of FIG. 5, which extend in the transverse direction of the covering 10 . The connecting elements 4 are connected, in particular welded, to the first longitudinal thread ends 3a and the second longitudinal thread ends 3b exclusively with their upper side 5 in a materially bonded manner.

The fabric connection 1 is arranged in such a way that the underside 5b of the connecting elements 4 is directed in the direction of the running side 12 of the clothing 10 . This arrangement of the fabric connection 1 influences the tendency of the press felt 10 to mark. The -if necessary overlapping- longitudinal thread ends 3a, 3b face the paper side 13 and the transversely arranged threads of the connecting elements 4 face the running side 12. As a result, the relatively densely packed longitudinal threads 3a, 3b (approx. twice the thread density in the connection area 1) minimizes possible mechanical markings starting from the connection elements 4. This is all the more important since, in advantageous embodiments, the transverse threads of the connecting elements 4 are at a greater distance from one another than the transverse threads 6 in the solid fabric.

FIGS. 6a and 6b also show examples of coverings 10 according to further aspects of the present invention. In contrast to Figure 5, the coverings 10 shown here each have a further fabric layer 15 in addition to the first fabric layer 14, with the first fabric layer 14 being arranged closer to the paper side 11 of the covering 10 than the further fabric layers 15. The further fabric layers 15 also have at least one fabric connection 1 according to one aspect of the present idea in these illustrations. In the case of the coverings 10 shown in FIGS. 6a and 6b, these fabric connections 1 are arranged essentially one above the other. However, it can often be advantageous if the fabric connections 1 of the first fabric layer 14 and the fabric connections 1 of the further fabric layer 15 are not arranged directly one above the other, but are offset from one another in the machine longitudinal direction (MD), and for example there is a MD distance of more than 10 cm or more than have 100 cm.

The difference between Figure 6a and Figure 6b is the orientation of the fabric connection 1 in the further fabric layer 15. In the case of the covering 10 in Figure 6a, the fabric connection 1 is oriented in the same way as that of the first fabric layer 14. The longitudinal thread ends 3a, 3b point to the Paper side 13 and the transversely arranged threads of the connecting elements 4 point to the running side 12. In the case of the covering 10 of FIG. 6b, on the other hand, the fabric connection 1 is oriented the other way around. Such an arrangement of the fabric connections 1 can in some cases be favorable in terms of production technology. For example, the fabric connection 1 of the further fabric layer 15 can be closed simply by transmission welding, in that the connection area is irradiated from the running side with laser light, for example. This light can then penetrate through the usually transparent longitudinal thread ends 3a, 3b, and is from the tops 5 of the Connecting elements absorbed, whereby the material connection is created. This is not possible in the embodiment as in FIG. 6, since the energy would be absorbed by the undersides 5b of the connecting elements 6 here. It is therefore not possible to weld the upper sides 5 to the longitudinal thread ends 3a, 3b.

FIGS. 7a to 7e show a possible production process for a woven basic structure for a covering 10, in particular for a covering 10 according to one aspect of the present invention.

A piece of fabric is folded at two folding points 20 and placed on itself in such a way that the two fabric ends 2a, 2b touch or overlap (FIGS. 7a and 7b). The two fabric ends 2a, 2b are then connected to one another by a fabric connection 1. For this purpose, the longitudinal thread ends 3a, 3b are usually cohesively connected to one another via one or more connecting elements 4. The connecting elements 4 extend, for example, in the form of threads in the transverse direction of the covering 10. The connection is made in such a way that the longitudinal thread ends 3a, 3b are only in contact with the upper side of the connecting element 4 or the connecting elements 4, and are firmly bonded to this. are in particular welded. To adjust the fabric connection, a number of transverse threads 6 can be removed from the fabric ends 2a, 2b in order to lengthen the longitudinal thread ends 3a, 3b. As shown in FIG. 7c, the fabric connection 1 is advantageously aligned in such a way that the underside 5b of the at least one connection element 4 points in the direction of the interior of the two-layer fabric being produced. As already described, the material-to-material connections can be easily implemented using transmission welding.

To produce a seam covering 10, in particular a seam felt 10, seam loops 21 are formed at the folds 20. For this purpose, a certain number of transverse threads 6 are removed from the fabric at these points. This removal often takes place before the fabric 10 is folded and placed on top of one another. Now the two-layer fabric can be sewn together by bringing the seam loops together

21 and connecting them by means of a pintle element to form a pintle seam

22 an endless fabric loop can be produced, which can be used as a basic structure for a covering 10 . The two options shown in FIGS. 7d and 7e are available.

In FIG. 7d, the seam loops 21 have been brought together in such a way that the fabric connection 1 is arranged in the position closer to the paper side 11. The result is that the fabric connection 1 is arranged in such a way that the underside 5b of the at least one connecting element 4 is directed in the direction of the running side 12 of the clothing 10 . Such a fabric loop as in FIG. 7d can thus also be used as the first fabric layer 14 in a covering 10 according to one aspect of the invention.

An alternative is shown in FIG. 7e. Here the seam loops 21 have been brought together in such a way that the fabric connection 1 is arranged in the position closer to the running side 12 . The result is that the fabric connection 1 is arranged in such a way that the underside 5b of the at least one connecting element 4 is directed in the direction of the paper side 11 of the covering 10 . Such a fabric loop as shown in FIG. 7e can also be used advantageously as a fabric layer 14--possibly also as a first fabric layer--in a covering 10, not least because of its simple manufacture.

Reference sign

I tissue connection

2a first tissue end

2b second tissue end

3a first longitudinal thread end

3b second longitudinal thread end

4 fastener

5 top

5b underside

6 cross threads

7 core

8 coat

10 covering

II paper side

12 running side

13 fleece layer

14 first layer of fabric

15 more layers of fabric

20 fold point

21 seam loop

22 pin seam

Claims

- 25 - Claims

1. Fabric connection (1) for a cover (10) of a machine for producing or processing a fibrous web, comprising a first fabric end (2a) with first longitudinal thread ends (3a) and a second fabric end (2b) with second longitudinal thread ends (3b), and at least a connecting element (4) which extends in the transverse direction of the subsequent covering (10), characterized in that the connecting element (4) has an upper side (5) and an underside (5b), and the first longitudinal thread ends (3a) and the second Longitudinal thread ends (3b) are only in contact with the upper side (5) of the connecting element (4) and are cohesively connected to it, in particular welded.

2. Clothing (10) for a machine for producing or processing a fibrous web with a paper side (11) in contact with the web and a running side (12) facing away from the web, the clothing (10) having at least a first fabric layer (14), characterized in that the first fabric layer (12) has at least one fabric connection (1) according to Claim 1, the fabric connection (1) being arranged in such a way that the underside (5b) of the at least one connecting element (1) faces in the direction of the running side (12) of the clothing (10 ) is directed.

3. Covering (10) according to claim 2, characterized in that the first fabric layer (14) has a plurality of fabric connections (1) according to claim 1, wherein all fabric connections (1) are arranged such that the underside (5b) of the respective connecting elements (4) is directed towards the running side (12) of the clothing (10).

4. Covering (10) according to one of claims 2 to 3, characterized in that the covering (10) has one or more further fabric layers (15), which also has a fabric connection (1), in particular according to claim 1, wherein the first Fabric layer (14) is arranged closer to the paper side (11) of the covering (10) than the other fabric layers (15).

5. Covering (10) according to one of Claims 2 to 4, characterized in that the covering (10) has at least one further fabric layer (15), the further fabric layer (15) being a round-woven fabric layer

6. Covering (10) according to one of Claims 2 to 5, characterized in that it is a press felt (10), the paper side (11) of the covering (10) being provided by a fleece layer which is connected to the or is connected to the fabric layers (14, 15) by needling.

7. Seam covering (10) for a machine for the production or processing of a

Fibrous web, with a paper side (11) in contact with the web and a running side (12) facing away from the web, the seam covering (10) comprising a basic structure which is realized in that a piece of fabric is folded at two folding points (20) and forms a two-layer fabric on itself is laid down itself, with the two fabric ends (2a, 2b) being connected to one another by a fabric connection (1), and with seam loops (21) being formed at the folds (20), with the seam loops (21) being connected by means of a pin-wire element to form one Pintle seam (22) an endless fabric loop is generated, characterized in that the

Tissue connection (1) is designed according to claim 1, wherein the tissue connection (1) is arranged so that the underside (5b) of the at least one connecting element (1) shows towards the interior of the resulting two-layer fabric.

8. Seam covering (10) according to claim 7, characterized in that the fabric connection (1) is arranged in the layer of the two-layer fabric closer to the paper side (11), the underside (5b) of the connecting element (4) in the direction of the running side ( 12) of the covering (10) is directed.

9. Seam covering (10) according to claim 7, characterized in that the fabric connection (1) is arranged in the layer of the two-layer fabric closer to the running side (12), the underside (5b) of the connecting element (4) pointing in the direction of the paper side ( 12) of the covering (10) is directed.