Spacer fabric and padding arrangement

Abstract

The invention relates to a spacer fabric with two knitted layers (1) and spacer threads (2) connecting the knitted layers (1), wherein the knitted layers (1) have successive stitches with a mean stitch spacing a in a production direction (P), wherein the knitted layers (1) have openings (3) extending along the production direction (P) over a length l, the length l being greater than 2*a, and wherein the openings (3) of the two knitted layers (1) are arranged substantially overlapping and thus form pairs of openings (4). At least in some of the pairs of openings (4), at least one pair (5) of intersecting spacer thread segments (6) extending over a transverse direction (Q) of the openings (3) is provided, wherein the number of pairs (5) of intersecting spacer thread segments (6) in these pairs of openings (4) is less than 1 / 2a.

Description

[0001] The invention relates to a spacer fabric with two knitted layers and spacer threads connecting the knitted layers, wherein the knitted layers have successive stitches in a production direction with a mean stitch spacing a, wherein the knitted layers have openings extending along the production direction over a length l, the length l being more than 2*a, and wherein the openings of the two knitted layers are arranged substantially overlapping and thus form pairs of openings. The invention further relates to a cushion arrangement, in particular a climate-controlled seat for a motor vehicle, incorporating the spacer fabric.

[0002] Spacer fabrics are characterized by a lightweight, air-permeable structure, and their elasticity is due to the spacer threads running between the two knitted layers. Monofilament yarns are typically used as spacer threads, which, due to their structure, exhibit a comparatively high resilience.

[0003] Due to their elastic properties, spacer fabrics can be used as soft, resilient layers that allow air circulation in mattresses, upholstered furniture, clothing, or shoes. Spacer fabrics are also used as technical textiles in the automotive sector, for example, for climate-controlled seats and seat covers, where their cushioning properties and excellent resilience allow for good contour adaptation.

[0004] The present invention relates in particular to the technical textiles mentioned above.

[0005] The assignment of production direction and cross direction is common in knitted textiles, with the production direction also being referred to as the knitting direction or longitudinal direction. In spacer fabrics, the individual threads forming the knit run along the production or knitting direction and, based on this, typically exhibit a repeating knitting pattern, whereby, for example, the spacer threads run back and forth between the two knit layers, thus keeping the two knit layers apart.

[0006] According to the usual definition, the two layers of knitted fabric have stitches running along the production direction and rows of stitches running along the transverse direction. The distance between successive rows of stitches in the production direction corresponds to the previously mentioned mean stitch spacing a.

[0007] A vehicle seat with a load-bearing spacer fabric in the area of ​​the seat surface is known, for example, from DE 100 13 492 A1. The spacer fabric is formed from two layers of knitted fabric and spacer threads connecting the layers. Particularly to create unsupported channels and creases, the spacer threads between the layers of knitted fabric can be omitted in certain areas.

[0008] From DE 10 2005 029 755 A1 a shape-adapted spacer fabric is known which, in addition to the openings (cf. Fig. 1, Fig. 2) The arrangement of the spacer threads is defined in different configurations across a repeating pattern. The permanent resilience is achieved through a specific number of spacer threads per unit area and / or through a special guidance of the spacer threads in the spacer fabric.

[0009] The present invention relates to a spacer fabric which has openings in both layers of the knit. It should be noted that textile products are generally not dense and that gaps and spaces are present within stitches or between two immediately adjacent stitches. Such gaps and spaces are not referred to as openings within the scope of the invention. Rather, the openings extend at least over the length of twice the stitch spacing, so that macroscopic and clearly perceptible openings are formed in relation to the actual stitch structure.

[0010] Additionally, the openings in the two knitted layers are arranged in a substantially overlapping manner. Substantial overlap exists, in particular, if the overlap, relative to the area of ​​the openings, is at least 70%. Preferably, the openings are completely overlapped, except for statistical and production-related variations.

[0011] Several aspects are important when using spacer fabrics for upholstery arrangements, especially in the form of a climate-controlled seat.

[0012] Naturally, the spacer fabric must have sufficient compressive strength to withstand the expected loads, such as the weight of a user of the climate-controlled seat. It is also advantageous if, when used as a fluid distribution layer, minimal flow resistance is achieved both within the plane of the spacer fabric and when flowing outwards from the fabric layers.

[0013] In the case of a spacer fabric with sufficiently large openings, the flow resistances in the area of ​​the spacer threads, i.e. in the plane between the layers of the fabric, play a particularly important role.

[0014] Furthermore, for reasons of cost and efficiency, it is advantageous if the spacer fabric can be manufactured as lightly as possible, because this means that less material is used and products with a lower weight can be manufactured.

[0015] Ultimately, not only sufficient compressive strength but also the tension profile during compression is crucial. It is often perceived as particularly pleasant if the spacer fabric feels soft under light compression and then develops sufficient tension as evenly as possible with increasing compression.

[0016] The stress distribution depends on a number of different factors. Crucially, the orientation of the spacer threads between the knitted layers is important, and the bending and buckling behavior of the individual spacer thread segments extending between the two layers can be considered. Furthermore, it must be taken into account that under stress, the material can deform and expand to a certain extent, so that, depending on the structure and load, the spacer threads can also tilt to one side. In such cases, sufficient support is generally not provided.

[0017] Against this background, it is also clear that the compression hardness and, in particular, the stress distribution during increasing compression depends both on the forces acting in the direction of the thickness and on their dissipation in the plane of the knitted fabric layers.

[0018] It should also be noted that the pattern of action created in the action process is also crucial for how the spacer fabric sets itself up or aligns itself after the action process.

[0019] A generic spacer fabric is known from DE 10 2008 020 287 B3, which is characterized by very good functional properties. The spacer threads are arranged such that, in a top view of the knitted layers, the spacer thread segments connecting the layers are arranged in an island-like fashion, leaving continuous channels between them that are kept free of spacer threads. The spacer fabric is characterized by both good mechanical properties and a particularly low flow resistance.

[0020] Against this background, it should be noted that in practice, the individual connections between the knitted layers are also referred to as spacer threads. Within the scope of the present invention, such a connection is referred to as a spacer thread segment, wherein the spacer threads running in the production direction thus form continuously successive spacer thread segments.

[0021] The present invention aims to provide a spacer fabric which exhibits particularly good mechanical properties with the lowest possible material usage and is therefore especially suitable for upholstery applications. Furthermore, an upholstery arrangement, particularly in the form of a climate-controlled seat for a motor vehicle, is to be specified.

[0022] The subject matter of the invention and the solution to the problem are a spacer fabric according to claim 1 and a cushion arrangement according to claim 15.

[0023] Based on a generic spacer fabric, the invention provides that at least one pair of intersecting spacer thread sections extending over a transverse direction of the openings is provided for at least some of the opening pairs, preferably for all opening pairs, wherein the number of pairs of intersecting spacer thread sections is less than l / 2a at these opening pairs.

[0024] The at least one pair of intersecting spacer thread segments provides a certain degree of stabilization and transverse force transmission in the area of ​​the opening pairs. However, according to the invention, intersecting spacer thread segments are not provided in every row of stitches in the area of ​​the openings. If, for example, all spacer threads were to run diagonally, the spacer fabric as a whole would exhibit only a comparatively low compressive strength, which would be insufficient for the intended applications.

[0025] Against this background, according to a preferred embodiment of the invention, the spacer threads are woven in a combined I-lay and skew pattern, wherein the ratio of spacer thread sections in I-lay to spacer thread sections in skew can be 3:1 to 12:1, in particular 4:1 to 6:1. A large proportion of the spacer thread sections are then formed in the form of an I-lay and thus contribute to high compressive strength and uniform compression behavior. The skew, which also forms the spacer thread sections crossing at the openings, leads to stabilization and further positive modulation of the compression behavior.

[0026] With regard to the opening pairs, it is not fundamentally impossible that the intersecting spacer thread sections of a pair may be offset from each other by, for example, one stitch row. However, a preferred embodiment is one in which the intersecting spacer thread sections of a pair are arranged at the same position with respect to the production direction, i.e., on the same stitch row, and thus form an X-shape.

[0027] According to a preferred embodiment of the invention, exactly one pair of intersecting spacer thread segments extending across the transverse direction of the openings is provided at each pair of openings. It is particularly advantageous if the pair of intersecting spacer thread segments is located in the middle, or at least approximately in the middle, of the pair of openings with respect to the production direction.

[0028] The length of the openings can be easily determined on the spacer fabric itself and depends to some extent on the specific knitting pattern of the layers and possibly other influencing factors such as yarn tension during the knitting process. The length of the openings can be between 3a and 12a, and particularly between 5a and 10a.

[0029] The openings are bordered by bridges formed from stitches, whereby stitches adjacent to the bridges can also be connected by sections of spacer thread. In this case, there is also a slant, and an X-shaped crossing is also possible. However, since the stitches run directly next to each other, the angle of the intersecting spacer thread sections is significantly smaller.

[0030] The described cross-linking at the webs can also advantageously contribute to stabilizing the entire spacer fabric.

[0031] The angle of the spacer thread segments crossing at the pairs of openings depends on the one hand on the overall thickness of the spacer fabric and on the other hand on the width of the openings. According to a preferred embodiment of the invention, the spacer thread segments crossing at the pairs of openings run at an angle between 25° and 60°, in particular between 35° and 55°, relative to the fabric layers.

[0032] According to a typical embodiment of the invention, the spacer thread segments crossing at the pairs of openings extend only across the width of the respective pair of openings. However, it is also fundamentally possible for the crossing to occur across two or more openings, for example, to achieve the aforementioned preferred angles in cases of specific ratios between the total thickness and width of the openings.

[0033] According to the invention, the spacer fabric preferably has a total thickness between 5 mm and 40 mm, although the invention is not limited to this range. A thickness between 8 mm and 15 mm is particularly preferred.

[0034] The spacer threads can preferably be formed with two guide rails, each guide rail having a "1 full, 1 empty" feed (every second needle being occupied by a thread). Monofilament yarns are particularly suitable, as they exhibit higher flexural strength compared to multifilament yarns due to their structure.

[0035] According to the invention, the openings of the two knitted layers are essentially aligned and thus form pairs of openings. Therefore, both knitted layers can also be laid down identically. Furthermore, the knitted layers can be made entirely identical with respect to the yarn used, with multifilament yarns being particularly suitable for both layers.

[0036] Within the scope of the invention, it is advantageous for the formation of the openings if the knitted layers are formed with at least two laying rails each, preferably exactly two laying rails.

[0037] It is possible that at least one of the knitted layers, preferably both knitted layers, has a first yarn system with a fringe arrangement and a second yarn system with a partial weft, wherein the partial weft connects adjacent fringe rods formed by the first yarn system to form the openings.

[0038] The spacer fabric according to the invention is also characterized by particularly good elastic properties with respect to compression. Generally, spacer fabrics can only be compressed over a portion of their total thickness due to the material used, because beyond a certain compression, the yarn material – similar to a coil spring – "blocks up." This also results in a steep increase in force and, in the case of excessive force, potentially permanent damage. In practice, such loads do not usually occur.

[0039] In standard measurement procedures, it is known to compress spacer fabrics by 70% of their total thickness. A test sample with a thickness of 10 mm is then compressed by 7 mm, leaving a thickness of 3 mm.

[0040] With dense and solid spacer fabrics, a force increase can occur that indicates the beginning of complete compression of the material. However, the invention specifically aims for a particularly lightweight spacer fabric with minimal material usage, so that blocking is generally not a concern even with appropriate compression.

[0041] For spacer fabrics, it is customary to specify the stress, i.e., the tensile strength, as a maximum value and / or at a specific deformation. However, detailed investigations of the stress as a function of deformation reveal very different curves for different materials, with the course of this characteristic being of particular importance for the haptic perception of the user.

[0042] Furthermore, it should be noted that spacer fabrics can be significantly stiffer immediately after production during the first deformation and may exhibit considerable deviations compared to their subsequent characteristics. Against this background, the following explanations refer specifically to the properties of the spacer fabric after the first compression. During the first compression, depending on the material, increased internal stresses, adhesions, or similar factors may still be present. After a certain number of deformations, the behavior becomes practically constant, with spacer fabrics being particularly distinguished by their permanent elasticity.

[0043] The mean mesh spacing a, and thus also the spacing of successive rows of mesh in the production direction, can be between 1 mm and 3 mm in particular.

[0044] According to a preferred embodiment of the invention, the spacer fabric is made of a uniform plastic material, in particular PET, so that single-stream recycling is also possible.

[0045] As previously explained, the spacer fabric should be as lightweight and breathable as possible. According to a preferred embodiment of the invention, the basis weight of the spacer fabric is between 250 g / m². 2 and 450 g / m² 2 , especially between 300 g / m² 2 and 350 g / m² 2 The specified basis weight refers in particular to a preferred thickness between 8 mm and 12 mm, especially about 10 mm.

[0046] The invention also relates to a cushion arrangement, in particular a climate-controlled seat for a motor vehicle, comprising a top layer and the spacer fabric described above, which is arranged below the top layer and is provided as a fluid distribution layer.

[0047] The invention is explained below with the aid of figures. These show: Fig. 1. A top view of a spacer fabric in the form of a photograph, Fig. 2. An oblique view of an edge of the spacer fabric according to the Fig. 1 in the form of a photograph, Fig. 3 a laying of laying rails intended for the formation of the spacer fabric in a working process, Fig. 4 a layout pattern for spacer threads of the spacer fabric, Fig. 5. A layout diagram for a first yarn system and a second yarn system to form the knitted layers. Fig. 6A a deformation-stress diagram for a spacer fabric according to the invention, and Fig. 6B / 6C Deformation-stress diagrams for spacer fabrics according to the state of the art.

[0048] The Fig. 1 and Fig. Figure 2 shows a spacer fabric with two knitted layers 1 connected by spacer threads 2. The structure becomes particularly apparent when considering the Fig. 1 and Fig. 2 clearly, because the knitted layers 1 in the illustrated embodiment are identical or substantially identical in design and the knitted layers 1 are distinct from each other in the top view of the Fig. 1. Cover.

[0049] The knitted layers 1 have, as usual, successive stitches in a production direction P with a mean stitch spacing a, wherein the knitted layers have openings 3 (see in particular Fig. 2).

[0050] As will also become apparent from the following explanations, the fact that it is described in the Fig. The spacer fabric shown has a repeat length of twelve stitches, meaning that the same structure results again after twelve stitches.

[0051] This also results in a further conclusion when considering the Fig. 1, that the openings 3 extend along a production direction P over a length l which is more than twice the mean mesh spacing a. As can also be seen from the Fig. As can be estimated, the length l can be, for example, between 5a and 10a.

[0052] According to the Fig. 2. The openings 3 of the two knitted layers 1 are perceptible separately from each other. In the top view according to the Fig. 1. However, the openings 3 of the two knitted layers 1 are essentially arranged in mutual overlap, so that corresponding pairs of openings 4 are visible in the top view.

[0053] It can be seen that at each pair of openings 4, exactly one pair of 5 intersecting spacer thread segments 6 extending across the transverse direction Q of the openings 3 are provided. The spacer thread segments 6 that intersect at the pairs of openings 4 run at an angle of approximately 45° to the knitted layers 1.

[0054] At each pair of openings 4, the pair of 5 intersecting spacer thread sections 6 is located in the center of the corresponding pair of openings 4 with respect to the production direction P. The spacer thread sections 6 intersecting at the pairs of openings 4 contribute particularly advantageously to stabilizing the spacer fabric in the transverse direction Q and to modulating the compression behavior.

[0055] Already in the Fig. 1 and Fig. 2 it is evident that the openings 3 in the knitted layers 1 are bounded by webs 7 formed from stitch rods, a preferred knitting pattern being explained in detail below.

[0056] The Fig. Figure 3 shows in this context an insertion scheme for six laying rails L1 to L6, in order to insert the one in the Fig. 1 and Fig. to be able to form the 2 spacer fabrics shown.

[0057] The two knitted layers 1 are formed on one side by the laying bars L1, L2 and on the other side by L5, L6. The spacer threads 2 are formed by the laying bars L3, L4, each with one full thread and one empty thread, whereby the full thread and the empty thread are offset by one needle pitch on the two laying bars L3, L4.

[0058] The Fig. Figure 4 shows the layout of the spacer threads 2, where the repeat length is twelve rows of stitches. It should be noted, however, that the spacer threads 2 are incorporated into both knitted layers 1 and are therefore attached to each of the two knitted layers in every row of stitches.

[0059] From the Fig. Figure 4 shows that the spacer threads 4 largely run straight in the production direction P, thus indicating an I-lay. At every third stitch (relative to the knitted layers 1), the spacer threads 2 formed by both laying rails L3 and L4 are laid at an angle, resulting in a crossover. These crossovers are located alternately at the openings 3 and at two immediately adjacent webs 7. These second crossovers are shown accordingly in the Fig. 1 and Fig. 2. Not perceptible, but also lead to a beneficial improvement of the spacer fabric.

[0060] The ratio of spacer thread sections in I-lay to spacer thread sections in skewed lay is therefore 5:1 in the illustrated embodiment.

[0061] The two knitted layers 1 are identical, wherein the Fig. Figure 5 shows the knitting pattern for both layers 1. For each of the two layers 1, a laying bar L2, L5 is provided, which, with a full draw-up using a first yarn system, creates fringe sticks through a fringe laying process. A further laying bar L1, L6, with a draw-up of 1 full, 1 empty, is assigned to a second yarn system, which forms a partial weft. The partial weft connects adjacent fringe sticks formed by the first yarn system to each other section by section, creating the openings 3.

[0062] The Fig. Figure 6A shows an exemplary deformation-stress diagram for a spacer fabric according to the invention, wherein the Fig. 6B and Fig. 6C shows corresponding diagrams for spacer fabrics from the prior art.

[0063] The deformation-stress diagrams each show an initial deformation, which is not relevant for the subsequent behavior of the spacer fabric, because only during the first deformation do significantly increased stress values ​​occur in spacer fabrics.

[0064] After repeated deformations, a consistent behavior is established, for which in the Fig. 6A to 6C each also show a corresponding route, to which the following explanations refer.

[0065] When determining the deformation-stress diagrams, a deformation of up to 70% of the total thickness occurs, followed by a stress relief. Fig. 6A shows that the compression behavior is particularly smooth. At the beginning of a compression cycle, the voltage initially rises slowly and then steadily before the slope decreases again prior to reaching the maximum compression of 70%.

[0066] The Fig. Figure 6B shows the strain-stress diagram for a spacer fabric from the prior art. This spacer fabric contains, among other yarns, a melt yarn which is at least partially melted during manufacturing. The melt yarn contributes to a certain degree of stabilization at specific points within the spacer fabric. The spacer fabric is particularly stiff during initial deformation, and these initial deformations can break some of the connections formed by the melt yarn.

[0067] After several deformations, a relatively steep increase in stress is observed following a soft initial phase, giving the user the impression of a comparatively hard material. This is followed by a relatively flat phase before another steeper increase is observed upon reaching the maximum deformation of 70%, which may indicate the beginning of blocking.

[0068] According to the Fig. 6C results in a similar behavior for a further spacer fabric according to the prior art as in the Fig.6B. The voltage rises relatively steeply over a comparatively short distance before reaching a kind of plateau. Additional compression then only leads to a very limited increase in voltage. Only before reaching the maximum compression of 70% does the gradient increase again. The middle section of the curve can be perceived by a user as an unpleasant "dead zone".

Claims

Spacer fabrics with two knitted layers (1) and spacer threads (2) connecting the knitted layers (1), wherein the knitted layers (1) have successive stitches with a mean stitch spacing a in a production direction (P), wherein the knitted layers (1) have openings (3) extending along the production direction (P) over a length l, wherein the length l is more than 2*a and wherein the openings (3) of the two knitted layers (1) are arranged substantially overlapping and accordingly form pairs of openings (4), characterized in that at least one pair (5) of intersecting spacer thread sections (6) extending over a transverse direction (Q) of the openings (3) is provided in at least one part of the pairs of openings (4), wherein the number of pairs (5) of intersecting spacer thread sections (6) in these pairs of openings (4) is less than 1 / 2a. Spacer fabric according to claim 1, characterized in that at least one pair (5) of intersecting spacer thread sections (6) extending over the transverse direction (Q) of the openings (3) is provided at each of the opening pairs (4). Spacer fabric according to claim 1 or 2, characterized in that exactly one pair (5) of intersecting spacer thread sections (6) extending over the transverse direction (Q) of the openings (3) is provided at the corresponding pairs of openings (4). Spacer fabric according to claim 3, characterized in that the pair (5) of intersecting spacer thread sections (6) is located in the middle of the opening pairs (4) with respect to the production direction (p). Spacer fabrics according to one of claims 1 to 4, characterized in that the length l of the openings (3) is between 3*a and 12*a, in particular between 5*a and 10*a. Spacer fabric according to one of claims 1 to 5, characterized in that the openings (3) are bounded by webs (7) formed from mesh rods, wherein spacer thread sections connecting adjacent mesh rods are provided on the webs (7). Spacer fabrics according to one of claims 1 to 6, characterized in that the spacer threads (2) are knitted in a combined I-lay and skew lay, wherein the proportion of spacer thread sections in I-lay to spacer thread sections in skew lay is 3:1 to 12:1, in particular 4:1 to 6:

1. Spacer fabric according to one of claims 1 to 7, characterized in that the spacer threads (2) are formed with two guide rails (L3, L4), each with one indentation 1 full, 1 empty. Spacer fabric according to one of claims 1 to 8, characterized in that the two fabric layers (1) have an identical layup. Spacer fabric according to one of claims 1 to 9, characterized in that the fabric layers (1) are each formed with two laying rails (L1, L2; L5, L6). Spacer fabric according to one of claims 1 to 10, characterized in that at least one of the knitted layers (1) has a first yarn system with a fringe arrangement and a second yarn system with a partial weft, wherein the partial weft connects section by section adjacent fringe rods formed by the first yarn system to form the openings (3). Spacer fabric according to one of claims 1 to 11, characterized in that the total thickness is between 5 mm and 40 mm. Spacer fabric according to any of claims 1 to 12, characterized in that the mean mesh spacing a is between 1 mm and 3 mm. Spacer fabric according to one of claims 1 to 13, characterized in that the spacer thread sections (6) crossing at the opening pairs (4) run at an angle between 25° and 65°, in particular between 35° and 55°, relative to the fabric layers (1). Upholstery arrangement, in particular climate seat for a motor vehicle, comprising a top layer and a spacer fabric arranged below the top layer according to one of claims 1 to 14 as a fluid distribution layer.

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