EP3252196A1 - Sewing device, method for producing a sewn multilayer structure and sewn multilayer structure - Google Patents

Abstract

The invention relates to a device, a method for forming a sewn multi-layer structure and a sewn multi-layer construction, comprising at least one upper cover sheet and at least one compressible intermediate layer. The apparatus comprises a machine mower, a conveyor (7) for at least one of the cover and / or intermediate layers and a lower throat plate (2) with tap hole (5 '), one to the lower throat plate (5') corresponding to the intended height of sewn multi-layer construction spaced upper throat plate (3) is provided, starting from a tap hole (5) starting a slot (4) which extends in the sewing direction to an edge of the upper throat plate (3). The upper throat plate (3) is provided for supporting the upper cover sheet.

Description

The invention relates to a sewing apparatus and a method for producing a sewn multi-layer construction, comprising at least an upper cover sheet and at least one compressible intermediate layer, the apparatus comprising a machine mower, a conveyor for at least one of the cover sheets and / or intermediate layers and comprising a lower stitch plate with stitch hole.

Such composite materials are known as the multi-layer construction of heat-insulating clothing products suitable for extreme weather conditions, such as quilted jackets as well as quilts, sleeping bags and similar products. These are produced in a multi-layer structure with insulation material between several layers of textile surfaces, which may additionally be, for example, water-repellent.

In order to exclude an undesired or even functionally damaging displacement of the individual layers against each other, an overstitching of the surface with seams is usually carried out. These seams can then have a decorative function in addition to the fixing function by their realized arrangement.

However, the known and commonly used sewing technology compresses the intermediate layer, e.g. As the insulation material, in the region of the seam, where the needle penetrates the layered material and brings the sewing threads under tension. The layered material is thereby thinner in the seam area compared to the rest of the material surface due to the tension of the suture, z. B. the needle thread and the lower thread. Because of the volume thus reduced, less heat-insulating air is present in the porous structure of the insulating material. This leads to local thermal bridges in the seam areas that cause heat losses at these locations. Therefore, these places can be called "cold spots" or so-called cold spots. In industrial practice, these cold spots are inevitably accepted because there is currently no other industrially usable option for product optimization.

However, the document offers an attempt to solve the problem DE 692 8 331 U1 , Reference is made to the common practice of interposing a spacer (p.2, Z. 18-21) or inserting textile strips (p.2, Z. 28-29). However, the document proposes not to provide a zig-zag sewing machine instead. This zigzag sewing machine includes a hold-down that is underneath the Needle middle position between the legs has a substantially horizontally oriented, free-running mandrel.

In the case of such a sewing machine foot, a mandrel is arranged between the hold-downs which are connected to one another at only one end and which terminate freely at the ends pointing in the direction of transport. Since the mandrel also passes through the stitch area of the needle, the machine must be set so that the needle punctures between the mandrel and the downers in the fabric.

In performing the stitches, the seam is passed over the mandrel so as to form a loop comprising the mandrel which slides along with the fabric feed on the smooth surface of the mandrel. Arranged at the end of the mandrel are erected free loops, which are tensioned during the inflation or filling of the space formed between the panels following the sewing process and drawn into the interior between the two panels. In this way, a seam with a large thread length and a corresponding distance between the two panels is produced by simple means.

However, the thread length is only as big as the thorn is thick. In addition, a subsequent spacing of the panels and a tensioning of the threads - in contrast to the spacer - required, which represents an additional risk for a stable and visually uniformly responsive end product.

Another practical measure to circumvent the aforementioned problem is the seam length reduction, which is associated with a lower positional fixation of the multi-layer structure. In particular for down fillings, a two-level chamber system is prepared, in which the downs are subsequently blown in, as well as in the above-described publication. However, the sewing-technical effort is comparatively much higher in this method.

Alternatively, it would be conceivable from a professional point of view to connect each outer layer with a layer of insulating material in a known manner, to then form the insulation of two such layers in the product.

The direct passage of air as a partial problem of the heat losses through the puncture holes can prevent the seam sealing by means of adhesive tape, so-called tapes, on the invisible inside. Here, however, a lining must hide the visibility of the tape, which is associated with additional effort and thus represents another disadvantage.

In any case, the originally desired thermal insulation is minimized locally in the stitching areas. The actual potential for thermal insulation in the material can not be fully exploited for the intended utility value.

Another solution to the problem provides the document DE 10 2014 200 824 A1 which describes a thermal insulation structure for a garment. By stitching two alternating forms of heat insulation structures are formed. The bulkier of the thermal insulation structures deforms under pressure as the garment rests close to the body and lays over the two adjacent stitching seams. This covers the area of the seams and has an improved insulation behavior. However, this effect is fragile and depends solely on a suitably concerted use, thus is not inherent in the thermal insulation structure.

A durable, but also more complex solution offers the document US 2,960,702 at. A blanket with staggered stitching provides improved insulation in the area of the stitching. However, each layer would have to be manufactured individually and then connected together, which greatly increases the production costs. In addition, the insulating effect is nevertheless reduced overall, because weakly insulating quilting seams are still present, but do not have a local effect, because they are covered by an area of another layer free of stitching seams.

Also the publication US 2013/0177731 A1 discloses a thermal insulation structure in which the seams are indeed covered and thereby protected against direct passage of air, but with regard to their heat-insulating effect no compensation for the reduced thickness of the insulating layer in the region of the seams is created.

An improved solution offers the publication US 3,837,021 according to which, for example, by a double-thread chain stitch or individual locking stitches such a distance of the two cover sheets is maintained to each other that an interposed insulating material with low compressive strength is not compressed by the seam. As a result, in particular the insulating effect of the insulating material is maintained. However, the production of seams is associated with increased effort.

Also after publication US 5,799,600 For example, in order to produce a quilted fabric from a pair of opposing fabric webs, individual stitches are provided which provide for a spaced connection of the two cover webs. However, the difficulty remains to introduce such basting stitches without pulling the two cover sheets against each other and thus to reduce the thickness of the insulating layer in an undesirable manner.

A simplification of the two aforementioned solutions, in which also both cover sheets are connected substantially parallel and spaced from each other, provides the document US 2015/0044400 A1 at. Here spacer elements are created from an additional material layer and integrated into the insulating layer. The spacers may be formed as webs or pockets, which at the same time avoid a local accumulation of loose insulation material such as down, which would otherwise occur without stitching. However, the production of the spacer elements requires additional material and labor.

The solutions known from the prior art are altogether unsuitable for solving the problem of a compacted intermediate layer in a multilayer structure or this is only possible with an increased expenditure of material and time when complicated elements are introduced to maintain the desired spacing.

The object of this invention is thus to easily cancel the locally minimized by undesirable compression of the insulation material heat insulation in seams, to propose a method and an apparatus therefor and a product produced with their help.

The object is achieved by a sewing device, generally a device for forming a sewn multi-layer structure, the at least one upper cover sheet but preferably at least one lower and one upper cover sheet, and at least one compressible intermediate layer. The compressible intermediate layer is compressible by at least 50% of its height, which it has in the unloaded state. However, such materials are regularly compressible by 80%, 90% or more. In particular, a thermal insulation material, for example a nonwoven fabric, a foam or even a loose filling is suitable as the intermediate layer. For textile applications, a fleece or a down filling would be conceivable. The device comprises a machine mower, as it is known as an essential part of a sewing machine, for example a flat bed sewing machine. As a rule, a continuous seam is produced with such a machine mower. Furthermore, a conveyor for at least one of the cover sheets and / or the intermediate layers is provided and a lower throat plate with stitch hole. According to the invention, an upper throat plate spaced from the lower throat plate is provided, wherein the distance is dimensioned according to the intended height of the sewn multi-layer structure such that the multi-layer structure fits into the gap. He is guided safely and not or only compressed to the extent necessary. The upper throat plate has a slot extending from a tap hole, which is aligned to the needle hole of the lower throat plate with respect to a Nadelhubs, and extends in the sewing direction to an edge of the upper throat plate. The upper throat plate is provided to support the upper cover sheet, which is to be considered especially in their attachment to a machine frame, so that the cover sheet can be moved to the upper throat plate.

In normal stitching, the thread systems are pulled taut during the stitch feed stage as part of the stitch forming operation, resulting in local compression of the material in the seam area. With the aid of an additional device according to the invention, the upper needle plate, the insertion of the sewing threads takes place only as far as it makes sense for the total thickness of the multi-layer structure. This means, of course, that more sewing thread length is consumed in the seam.

A normal sewing machine has a stitch plate, also called working plane, whereupon the fabric rests when sewing. For the purposes of the invention, a second throat plate is integrated into the active pairing, on which rests the upper cover sheet for sewing. The distance between the throat plates should be so large that the compression on the layer structure is minimized. Therefore, the upper throat plate itself has one small thickness on. The fabric with insulation material (lower cover sheet, if present, and intermediate layer or insulation material) is guided between the two throat plates in the space formed. Only the upper cover sheet slides over the upper needle plate, the outer material layer in the multi-layer construction. The distance between the throat plates determines the height of the seam and also the height of the multi-layer structure (partially compressed by thread tension). However, the height of the multi-layer structure may also differ from the distance between the throat plates. With increased tension in the sewn thread system results in a reduced height of the multi-layer structure, with compression of the multi-layer structure between the throat plates, but low thread tension, relaxes the multi-layer structure after leaving the gap between the throat plates.

A second significant advantage of this invention is the guide path in the upper stitch plate for the sewing threads of the newly formed stitch. The newly formed stitch needs an "escape route" to leave the sewing machine or upper needle plate. The small gap formed as a slit, which begins at the periphery of the stitch hole and ends at the edge of the throat plate in the direction of the material withdrawal, clearing the way for the stitching done so that the multilayer structure formed can leave the area of seam formation

It is advantageous if the conveyor is designed as a conveyor or as a deduction device. This ensures a uniform stitch length and a straight seam. It has proven to be advantageous if the conveyor for the upper cover sheet is designed so that it causes a different from the web speed of the other layers web speed. The upper cover sheet thus has, in particular, a higher speed, so that more material can be sewn in terms of length than in the lower cover sheet and also the intermediate layer. This can cause special effects on the finished multi-layer structure, such as. B. a curvature or a textured surface, for. B. by the formation of wrinkles.

Particularly advantageous is a sewing device in which a device for short-stroke horizontal movement, for example by vibration, the cover sheets and the intermediate layer of the sewn multi-layer structure is provided against each other. One possible solution to this is, for example, that the deduction device is designed for the sewn multi-layer structure for performing short-stroke horizontal movements. This can be done by the rollers that take the trigger vibrate in a horizontal plane, for example along their axes.

It has proven to be convenient to combine several sewing devices for forming a sewn multi-layer construction to a multi-needle stitching plant in order to produce the multi-layer structure with high productivity, for example as a semi-finished product for manufacturing other products thereof.

The object of the invention is also achieved by a method for forming a sewn multi-layer construction, comprising at least one upper cover sheet, but preferably a lower and an upper cover sheet, and at least one at least slight, slightly compressible intermediate layer, in particular a thermal insulation material, for example a foam or a loose filling. According to the prior art, the unwanted compression is regularly caused already by the thread tension. The multi-layer structure is by means of continuous, preferably simple, for example, straight machine seam with tensioned suture, z. B. an upper thread tension and a lower thread tension (eg, lockstitch or chain stitch) sewn. At least the intermediate layer, if present the lower cover sheet at the lower surface of the intermediate layer, slides over a lower throat plate, the upper cover sheet sliding on an upper stitch plate spaced from the lower, the distance being selected such that the intermediate layer, e.g. For example, the insulating material can slide therebetween, substantially without being compressed.

The inventive method is particularly intended for textile cover sheets and introduced between these thermal insulation material, such. As a fiber layer or down, which are sewn to the cover sheets by the insulation material, if present, the lower cover sheet is introduced for sewing in a space between the lower and the upper throat plate. The distance determines the height of the seam and thus the degree of compression of the insulation material.

As far as a device for short-stroke horizontal movement of the cover sheets and the intermediate layer of the sewn multi-layer construction is provided against each other, For example, by vibrations, this ensures that compensate for the thread tension of upper thread and lower thread and thereby create evenly to the cover sheets.

An advantageous development of the method provides that the material to be sewn is fed from a storage device, preferably in each case one roll for the cover sheet or cover sheets, and one or more intermediate layers. Likewise, it is alternatively or additionally provided that the multi-layer structure is accommodated by a storage device, preferably a roll, particularly preferably under tension or separate draw. The multilayer construction can be produced in this way as a semifinished product, stored and subjected to further processing, e.g. B. to quilts, clothing or sleeping bags to be further processed. In order to avoid tensions when sewing, in the region of the point of action, the deduction takes place in such a way that no or only minimal forces are registered in the cover sheets and intermediate layers. For this purpose, numerous possibilities are known from the prior art, such as. B. an additional own drive of the roles.

As a result, in addition to the undesirable stresses in the webs and tensile forces during the phase of seam formation are avoided. This is important to get the smallest possible, so dense puncture hole. For the same reason, the pierced needle is also not used for feed, but preferably the deduction device. This can be operated discontinuously, for example by a stepper motor, so that a tensile force is always applied only when the needle is not in engagement with the material webs to be sewn.
A further advantageous embodiment of the method according to the invention relates to the upper cover sheet, which has a different from the web speed of the other layers web speed when sewing to the multi-layer structure. This leads to a greater length of the faster web, which can lead, inter alia, to the effects described below.

A proposed effect is that the sewn multi-layer construction forms a spherical curvature with the web at the higher speed than the concave side. As a result, z. B. supporting properties caused and used or the multilayer structure are inserted without further transformation in a larger three-dimensional structure.

A second effect relates to a unilaterally structured surface, for. Small wrinkles, with the higher speed web forming the structured surface. As a result, the surface receives not only an optical effect due to the resulting roughness and an increased heat transfer resistance, especially against a flowing medium.

A solution of the object according to the invention also provides a multilayer structure comprising at least one upper cover sheet, but preferably a lower and an upper cover sheet, and at least one light, especially compressible by the thread tension of a sewing seam intermediate layer, wherein in particular a thermal insulation material is included. The layers of the multi-layer construction are sewn by means of simple, for example straight, in particular continuous machine seams with an upper thread tension and, if present, also a lower thread tension, whereby the machine seams run parallel and the multi-layer structure in seam areas has substantially the same height as outside the seam areas. The latter represents the decisive advantage of the invention, because without compression also in the seam area, the substantially identical insulating effect is produced and the seam areas, in contrast to the prior art, have no undesirable cold bridges.

As already described above for the production method, an advantageous multi-layer construction according to the invention is such that at least two cover sheets of different lengths are sewn. As a result, the multilayer construction has a spherical curvature in the seaming direction, with the longer of the cover webs forming the concave side. In another embodiment, the longer cover sheet is gathered and has a surface structure which in preferred embodiments has an optical effect and / or an additional thermal insulation effect or increases the heat transfer resistance.

A particularly preferred multi-layer structure provides at least two textile cover sheets and a heat-insulating intermediate layer, which together form a heat-insulating textile composite. Such a heat-insulating textile composite can be used, for example, as a clothing, sleeping bag or quilt or manufactured as a semi-finished to be processed into one of the aforementioned products.

The essential advantages of this invention can be exploited in the application in the production of heat-insulating clothing and heat-insulating textile equipment in the outdoor area, in the work area or in general technical textiles. For textile composites and also smart textiles with multi-layer construction, the use of the invention will bring positive effects in the product properties. Infrared images and thermal resistance measurements show positive results in the form of avoided thermal bridges.

In addition, this type of sewing process can also be used to achieve as constant as possible distances between the cover sheets for composites of the plastics industry with, for example foam layers. With the proposed system, it is not necessary to perform intersecting seams, but this is not possible at the same time.

• Fig. 1: schematisch eine perspektivische Darstellung einer Ausführungsform einer Wirkstelle einer erfindungsgemäßen Nähvorrichtung;
• Fig. 2: schematisch eine perspektivische Darstellung einer Ausführungsform einer Wirkstelle einer erfindungsgemäßen Nähvorrichtung mit ausgeführter Nähverbindung;
• Fig. 3: schematisch einer Ausführungsform einer erfindungsgemäßen Mehrnadelsteppanlage; und
• Fig.4: schematisch eine Ausführungsform eines erfindungsgemäßen Mehrschichtaufbaus in Schnittdarstellung.

Further details, features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

• Fig. 1 FIG. 2 schematically shows a perspective view of an embodiment of an effective point of a sewing device according to the invention; FIG.
• Fig. 2 FIG. 2 schematically shows a perspective view of an embodiment of an operative point of a sewing device according to the invention with a executed sewing connection; FIG.
• Fig. 3 FIG. 2: schematically, an embodiment of a multi-needle stitching system according to the invention; FIG. and
• Figure 4 FIG. 2 schematically shows an embodiment of a multilayer structure according to the invention in a sectional view. FIG.

Fig. 1 schematically shows a perspective view of an embodiment of an operative point of a sewing device 1 according to the invention, wherein a lower throat plate 2 has a tap hole 5 'and in the illustrated, preferred embodiment, a feed dog 7, of which here the slots are visible, in which it is movably guided , Spaced from the lower throat plate 2, an upper needle plate 3 is arranged, which also has a tap hole 5, but in addition has a slot 4, through which the seam formed can leave the upper throat plate 3.

A slot 4 is required because the upper cover sheet slides over the upper throat plate 3, while below the other layers are, for example, the lower cover sheet and the insulating sheet, and are sewn to the upper cover sheet in the area of the stitch hole 5.

Fig. 2 schematically shows a perspective view of an embodiment of an operative point of a sewing device 1 according to the invention with executed seam connection, wherein the feed direction 8 is indicated during the sewing process. The upper thread 10 and the lower thread 11 and the nodes 12 formed by both are shown. The upper thread 10 is inserted through the needle, not shown, through the stitch holes 5, 5 ', the same needle through the stitch holes 5, 5' brings up the lower thread 11. The materials to be sewn are not shown here for the sake of clarity. Reference is made to FIG. 5.

Fig. 3 schematically shows an embodiment of a multi-needle paving system 20 according to the invention. Here, the individual layers of the multi-layer structure 24 are each supplied from a memory, here of at least one roller. The finished multilayer structure 24 is also wound on a roll according to the illustrated embodiment. The upper cover sheet 21 is guided by a trigger 34 with abutment 35, so that the upper cover sheet 21 can be fed to the sewing process at a higher speed, therefore, more material of the upper cover sheet 21 is sewn in the multi-layer structure 24. Depending on the material properties and type of sewing process, the upper cover sheet 21 may receive a structure, for example, be curled, or the greater length of the upper cover sheet 21 cause the entire multi-layer structure 24 receives a curvature.

The supply of the insulating sheet 22 and the lower cover sheet 23 is also carried out by rollers, wherein the feed takes place by a downstream discharge device 30, which dissipates the already formed multi-layer structure 24 from the sewing process, thus also pulling the webs of the active site opposite side feeds.

The sewing apparatus 1 comprises, as already shown in the preceding figures, a lower throat plate 2 and an upper throat plate 3. By not shown here stitch holes, the needle 31 leads the not shown here Upper thread in the multi-layer structure 24 and pulls up the lower thread after formation of a knot again. As an alternative to the feed by means of the removal device 30, it is also provided to provide the throat plate 2 with a feed dog, which ensures the advance of the web.

Fig. 4 schematically shows an embodiment of a multi-layer structure 24 according to the invention in a sectional view. Between the upper cover sheet 21 and the lower cover sheet 23, an intermediate layer 22 is introduced, here an insulating sheet. As an intermediate layer is basically any material in question, which can be pierced by the needle during sewing. Also suitable are granule-like or particulate, in any case non-integral materials, which have a sufficient particle size and a texture such that they can be fixed by the sewing process. An example of this are down, which could also be introduced as insulating material between the cover sheets 21, 22. Particularly preferably, the insulating sheet 22 shows an elastic behavior, since in this case the seam remains under tension after slight compression during sewing.

The stitching is formed by the upper thread 10 and the lower thread 11. The upper thread 10 and lower thread 11 are knotted during the sewing process to form a knot 12, which ideally lies in the middle between the cover sheets 21, 23 within the insulating web 22.

A stronger compression of the insulating sheet 22 or of the entire multi-layer structure 24 is omitted, since by applying the method according to the invention the sewing of the multilayer structure 24 forming layers at substantially the intended final thickness and without compressing the materials during sewing. This is associated with the particular advantage that the insulating properties of the insulating sheet 22 in the region of the seam do not deviate or do not differ substantially from those that it has outside the seam. Even the puncture holes 25, which are directly adjacent to each other in the sewing process according to the prior art and thus allow heat loss, are here by the height of the insulating sheet 22 spaced so far that about incoming air is distributed in the insulating sheet 22 and not directly to the opposite manhole 25 can pass, as in the known, compressed in the seam area sewing products. The same applies to heat losses due to heat radiation or Heat conduction. This effect also contributes significantly to an improved insulation behavior and, for example when used as a garment, for improved wearing comfort.

LIST OF REFERENCE NUMBERS

1

suturing device

2

lower throat plate

3

upper throat plate

4

slot

5.5 '

tap hole

6

distance

7

Conveyor, transporter

8th

Feed direction of sewing material, sewing direction

9

gap

10

upper thread

11

lower thread

12

node

20

Multi-needle quilting conditioning

21

upper cover sheet

22

Intermediate layer, insulating sheet

23

lower cover sheet

24

Multilayer structure

25

puncture hole

30

Deduction device, trigger multi-layer construction

31

needle

34

Dumping device, deduction upper decking

35

abutment

36

idler pulley

Claims (15)

Sewing device for producing a sewn multi-layer structure (24) comprising at least one upper cover sheet (21) and at least one compressible intermediate layer (22), the sewing device comprising a machine mower, a conveyor (7) for at least one of the cover sheets (21, 23) and / or intermediate layers (22) and a lower throat plate (2) with stitch hole (5 '), characterized in that to the lower throat plate (2) according to the intended height of the sewn multi-layer structure (24) spaced upper throat plate (3) is provided of a stitch hole (5), which is aligned with the needle hole (5 ') of the lower throat plate (2) with respect to a Nadelhubs, starting from a slot (4) extending in the sewing direction (8) to an edge of the upper Throat plate (3) extends, and wherein the upper throat plate (3) for supporting the upper cover sheet (21) is provided. Sewing device according to claim 1, wherein the conveyor is designed as a feed dog (7) or as a withdrawal device (30, 34). Sewing device according to claim 1 or 2, wherein the conveyor means (7) for the upper cover web (21) is designed so that it causes a different from the web speed of the other layers web speed. Sewing device according to one of claims 1 to 3, wherein a device for short-stroke horizontal movement of the cover sheets (21, 23) and the intermediate layer (22) of the sewn multilayer structure (24) against each other is provided. Sewing device according to claim 4, wherein the removal device (30) is designed for carrying out short-stroke horizontal movements. Sewing device according to one of the preceding claims, wherein a plurality of sewing devices (1) are combined to form a multi-needle stitching system. A method of making a sewn multi-layer construction (24) comprising at least an upper cover sheet (21) and at least one compressible intermediate layer (22) sewn by continuous machine seam, at least the intermediate layer (22) sliding over a lower throat plate (2), characterized in that the upper cover sheet (21) slides on an upper stitch plate (23) spaced from the lower one. The method of claim 7, wherein textile cover sheets (21, 23) and between these thermal insulation material are sewn as an intermediate layer (22) by the insulation material for sewing in a space between the lower throat plate (21) and the upper throat plate (23) is introduced , The method of claim 7 or 8, wherein the cover sheets (21, 23) and / or the intermediate layer (22) is supplied from a storage device and / or the multi-layer structure (24) is received by a storage device. Method according to one of claims 7 to 9, wherein short-stroke horizontal movement of the cover sheets (21, 23) and the intermediate layer (22) are registered against each other in the sewn multi-layer structure (24), so that a compensation of the thread tensions of upper thread (10) and lower thread (11 ) is achieved. Method according to one of claims 7 to 10, wherein the upper cover sheet (21) has, during sewing to the multi-layer construction (24), a different web speed from the web speed of the remaining layers. The method of claim 11, wherein the stitched multi-layer construction (24) forms a spherical dome with the higher speed web than a concave side or a one-sided textured surface, the higher speed web forming the structured surface. A multi-layer construction comprising at least one upper cover sheet (21) and at least one compressible intermediate layer (22) sewn by continuous machine seams, characterized in that the compressible intermediate layer (22) is compressible by at least 50% of its height in the unloaded state, the machine seams run continuously and parallel and the multi-layer structure (24) in seam areas substantially the same height as outside the seam areas. A multilayer construction according to claim 13, wherein at least two cover sheets (21, 23) of different lengths are sewn and the multi-layer construction (24) has a spherical curvature in the seaming direction, the longer of the cover sheets (21, 23) forming the concave side, or the longer cover sheet (21, 23) is gathered and has a surface structure. Multilayer structure according to one of claims 13 or 14, wherein at least two textile cover sheets (21, 23) and a heat-insulating intermediate layer (22) are provided, which together form a heat-insulating textile composite.

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