Spacer fabric and cushion assembly

Abstract

The invention relates to a spacer fabric comprising two fabric layers (1) and spacer threads (2) which connect the fabric layers (1). The fabric layers (1) have loops which follow one another in a production direction (P) with an average loop spacing a, wherein the fabric layers (1) have openings (3) which extend over a length l along the production direction (P), said length l equaling more than 2*a, and the openings (3) of the two fabric layers (1) substantially overlap with one another and form corresponding opening pairs (4). In at least some of the opening pairs (4), at least one respective pair (5) of spacer thread portions (6) is provided, said spacer thread portions crossing each other and extending over a transverse direction (Q) of the openings (3). The number of pairs (5) of crossing spacer thread portions (6) at the aforementioned opening pairs (4) is less than l / 2a.

Description

[0001] Spacer fabric and padding arrangement

[0002] Description:

[0003] The invention relates to a spacer fabric with two layers and spacer threads connecting the layers. The layers have successive stitches in a production direction with an average stitch spacing a. The layers have openings that extend along the production direction over a length I, the length I being more than 2*a, and the openings of the two layers are arranged substantially in mutual overlap, forming opening pairs. The invention further relates to a cushioning arrangement, in particular a climate-controlled seat for a motor vehicle, comprising the spacer fabric.

[0004] Spacer fabrics are characterized by a lightweight, breathable structure. They are elastic along their thickness due to the spacer threads running between the two layers. Monofilament yarns are typically used as spacer threads, which, due to their structure, exhibit a comparatively high recovery effect.

[0005] Due to their elastic properties, spacer fabrics can be used as soft, elastic, and air-circulating layers 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. Their cushioning properties and excellent resilience allow for good contour adaptation.

[0006] The present invention relates in particular to the latter technical textiles.

[0007]

[0008] The assignment of the production direction and the transverse direction is common in knitted textiles, whereby the production direction is also referred to as the weaving direction or longitudinal direction. In spacer fabrics, the individual threads forming the knitted fabric run along the production or weaving direction and, based on this, usually exhibit a recurring weaving pattern, according to which, for example, the spacer threads run back and forth between the two knitted layers, thus keeping the two layers apart.

[0009] According to the usual definition, the two flat knitted fabric layers have wales running along the production direction and rows running along the transverse direction. The spacing between consecutive rows in the production direction corresponds to the previously mentioned average stitch spacing a.

[0010] 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 fabric and spacer threads connecting the layers. The spacer threads between the layers can be omitted in some areas, particularly to create unsupported channels and kinks.

[0011] DE 10 2005 029 755 A1 discloses a form-fitting spacer fabric which, in addition to the openings (see Figures 1 and 2), defines the spacer thread arrangement in various designs via a repeat pattern. The permanent recovery properties are achieved by a specific number of spacer threads per unit area and / or by a special guidance of the spacer threads of the spacer fabric.

[0012]

[0013] The present invention relates to a spacer fabric that has openings in both layers. It should be noted that textile products are generally not dense and that individual gaps and open spaces may also occur within stitches or between two immediately adjacent stitches. Such gaps and open 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, thus creating macroscopic and clearly perceptible openings compared to the actual stitch structure.

[0014] Additionally, the openings in the two knitted fabric layers are arranged to substantially overlap each other. Substantial overlap is present in particular when the overlap is at least 70% of the area of ​​the openings. Preferably, the openings are completely overlapped, except for statistical and production-related fluctuations.

[0015] When using spacer fabrics for upholstery arrangements, particularly in the form of a climate seat, various aspects are important.

[0016] Of course, 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, the lowest possible flow resistance is achieved, both within the plane of the spacer fabric and during flow out of the fabric layers.

[0017]

[0018] In the case of a spacer fabric with sufficiently large openings, the flow resistance in the area of ​​the spacer threads, i.e. in the plane between the fabric layers, plays a particularly important role.

[0019] 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, on the other hand, products can be manufactured with a lower weight.

[0020] Ultimately, it's not just sufficient compression strength that's crucial, but also the tension distribution during compression. It can often be particularly pleasant if the spacer fabric feels soft during light compression and then develops sufficient tension as evenly as possible with increasing compression.

[0021] The stress distribution depends on a number of different factors. A crucial factor, for example, is the distribution of the spacer threads between the knitted fabric layers, where the bending and buckling behavior of the individual spacer thread sections extending between the two knitted fabric layers can be considered. Furthermore, it should be noted that when a force is applied, the material can be deformed and expands to a certain extent across its width, so that, depending on the structure and load, the spacer threads can even tilt to one side altogether. In this case, sufficient support is usually not provided.

[0022] Against this background, it is also clear that the compressive strength and in particular the stress distribution with increasing compression depend on both the

[0023] forces acting in the direction of the thickness as well as their derivation in the plane of the knitted fabric layers.

[0024] It should also be noted that the weaving pattern created in the weaving process is also decisive for how the spacer fabric is positioned or aligned after the weaving process.

[0025] DE 10 2008 020 287 B3 discloses a generic spacer fabric characterized by excellent functional properties. The spacer threads are arranged in such a way that, viewed from above, the spacer thread sections connecting the layers are arranged in islands, leaving continuous channels between them that are kept free of spacer threads. This spacer fabric is characterized by both good mechanical properties and particularly low flow resistance.

[0026] Against this background, it should be noted that in practice, the individual connections between the knitted fabric layers are also referred to as spacer threads. In the context of the present invention, such a connection is referred to as a spacer thread section, with the spacer threads running in the direction of production thus forming consecutive spacer thread sections.

[0027] The present invention is based on the object of providing a spacer fabric that exhibits particularly good mechanical properties while using as little material as possible, making it particularly suitable for a cushioning arrangement. Furthermore, a cushioning arrangement, particularly in the form of a climate-controlled seat for a motor vehicle, is to be provided.

[0028]

[0029] The subject matter of the invention and the solution to the problem are a spacer fabric according to patent claim 1 and a cushioning arrangement according to patent claim 15.

[0030] Starting from a generic spacer fabric, it is accordingly provided according to the invention that at least some of the opening pairs, preferably all opening pairs, are provided with at least one pair of intersecting spacer thread sections extending across a transverse direction of the openings, wherein the number of pairs of intersecting spacer thread sections at these opening pairs is less than l / 2a.

[0031] The at least one pair of intersecting spacer thread sections achieves a certain degree of stabilization and force transmission in the transverse direction in the area of ​​the opening pairs. However, the invention provides that intersecting spacer thread sections are not provided in every stitch row in the area of ​​the openings. If, for example, all spacer threads were to run diagonally, the spacer fabric as a whole would have a comparatively low compression strength, which would be insufficient for the intended applications.

[0032] Against this background, according to a preferred embodiment of the invention, the spacer threads are knitted in a combined I-lay and slant lay, whereby the ratio of spacer thread sections in I-lay to spacer thread sections in slant lay can be 3:1 to 12:1, in particular 4:1 to 6:1. A large portion of the spacer thread sections is then formed in the form of an I-lay and thus contributes to a high compression strength and uniform compression behavior. The slant lay, which in particular also forms the spacer thread sections crossing at the openings,

[0033] leads to stabilization and further positive modulation of the compression behavior.

[0034] With regard to the opening pairs, it is not fundamentally impossible for the intersecting spacer thread sections of a pair to be offset from each other by, for example, one stitch row. However, a preferred configuration 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, thus forming an X-shape.

[0035] According to a preferred embodiment of the invention, exactly one pair of intersecting spacer thread sections extending across the transverse direction of the openings is provided at the pairs of openings. It is particularly expedient if the pair of intersecting spacer thread sections is located in the middle or at least approximately in the middle of the pairs of openings with respect to the production direction.

[0036] The length of the openings can be easily determined on the spacer fabric itself and depends to a certain extent on the specific weaving pattern of the knitted layers and, in some cases, on other influencing factors such as thread tension during the weaving process. The length of the openings can be between 3a and 12a, especially between 5a and 10a.

[0037] The openings are bordered by webs formed by wales, whereby adjacent wales can also be connected by spacer thread sections. In this case, too, a slant lay is present, whereby a crossing in the form of an X-lay can also be provided.

[0038] However, since the wales run directly next to each other, the angle between the intersecting spacer thread sections is significantly smaller.

[0039] The described crossing of the webs can also advantageously contribute to stabilizing the entire spacer fabric.

[0040] The angle of the spacer thread sections intersecting at the pairs of openings depends on the total thickness of the spacer fabric and the width of the openings. According to a preferred embodiment of the invention, the spacer thread sections intersecting at the pairs of openings extend at an angle of between 25° and 60°, in particular between 35° and 55°, relative to the knitted fabric layers.

[0041] According to a typical embodiment within the scope of the invention, the spacer thread sections crossing at the pairs of openings extend only across the width of the corresponding pair of openings. However, it is not excluded in principle that a crossing occurs across two or more openings, for example, in order to be able to represent the aforementioned preferred angles in the case of special ratios of the total thickness to the width of the openings.

[0042] Within the scope of 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.

[0043] The spacer threads can preferably be formed with two guide rails, whereby a feed “1 full, 1 empty” is then particularly suitable on the guide rails (each second needle is fitted with a thread).

[0044] This applies in particular to monofilament yarns, which, due to their structure, have a higher bending strength than multifilament yarns.

[0045] Within the scope of the invention, it is provided that the openings of the two knitted fabric layers are essentially aligned and thus form pairs of openings. Against this background, an identical lay-up can also be provided for both knitted fabric layers. Furthermore, the knitted fabric layers can also be constructed with the same yarn overall, with multifilament yarns being particularly suitable for both knitted fabric layers.

[0046] Within the scope of the invention, it is expedient for the formation of the openings if the knitted fabric layers are each formed with at least two laying rails, preferably exactly two laying rails.

[0047] It is possible for at least one of the knitted fabric layers, preferably both knitted fabric layers, to have a first thread system with a fringe arrangement and a second thread system with a partial weft, wherein adjacent fringe rods formed by the first thread system are connected in sections by the partial weft to form the openings.

[0048] The spacer fabric according to the invention is also characterized by particularly good elastic properties with respect to compression. Due to the material used, spacer fabrics can generally only be compressed over a portion of their total thickness, because beyond a certain compression level, the thread material used "blocks" – similar to a coil spring. This also results in a steep increase in force and, if the force is too great, potentially even permanent damage. Such loads generally do not occur in practice.

[0049]

[0050] In this context, conventional measurement methods typically 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.

[0051] In dense and full spacer fabrics, this can already result in an increase in force, indicating the beginning of complete compression of the material. However, the invention aims to achieve a particularly lightweight spacer fabric with minimal material usage, so that blocking is generally not a concern even with such compression.

[0052] For spacer fabrics, it is known that the stress, i.e., the compression strength, can be specified as a maximum value and / or at a specific deformation. However, detailed studies of stress as a function of deformation reveal very different patterns for different materials, with the pattern of the characteristic being particularly important for the user's haptic perception.

[0053] Furthermore, it should be noted that spacer fabrics can be significantly harder immediately after production upon initial deformation and can exhibit significant deviations from their subsequent characteristics. Against this background, the following explanations refer in particular to the properties of the spacer fabric after initial compression. Depending on the material, increased internal stresses, adhesions, or similar effects may still be present during initial compression. After a certain number of deformations, the behavior remains virtually constant, with spacer fabrics being particularly distinguished by their permanent elasticity.

[0054]

[0055] The average mesh spacing a and thus also the spacing between successive rows of stitches in the direction of production can in particular be between 1 mm and 3 mm.

[0056] According to a preferred embodiment of the invention, the spacer fabric is formed from a uniform plastic material, in particular PET, so that pure recycling is then also possible.

[0057] As already explained, the spacer fabric should be as light and breathable as possible. Thus, according to a preferred embodiment of the invention, the weight per unit area of ​​the spacer fabric should be between 250 g / m 2 and 450 g / m 2 , especially between 300 g / m 2 and 350 g / m 2 The specified basis weight refers in particular to a preferred thickness between 8 mm and 12 mm, in particular about 10 mm.

[0058] The invention also relates to a cushion arrangement, in particular a climate-controlled seat for a motor vehicle, comprising a cover layer and the previously described spacer fabric, which is arranged below the cover layer and is provided as a fluid distribution layer.

[0059] The invention is explained below with reference to the figures. They show:

[0060] Fig. 1 is a plan view of a spacer fabric in the form of a photograph,

[0061] Fig. 2 is an oblique view of an edge of the spacer fabric according to Fig. 1 in the form of a photograph,

[0062]

[0063] Fig. 3 shows a covering of laying rails in a knitting process intended for the formation of the spacer fabric,

[0064] Fig. 4 a layout diagram for spacer threads of the spacer fabric,

[0065] Fig. 5 shows a laying pattern for a first thread system and a second thread system to form the knitted fabric layers,

[0066] Fig. 6A is a deformation-stress diagram for a spacer fabric according to the invention, and

[0067] Fig. 6B / 6C Deformation-stress diagrams for spacer fabrics according to the state of the art.

[0068] Figures 1 and 2 show a spacer fabric with two knitted layers 1 that are connected to each other by spacer threads 2. The structure becomes particularly clear when Fig. 1 and Fig. 2 are viewed together, because the knitted layers 1 in the illustrated embodiment are identical or essentially identical, and the knitted layers 1 overlap each other in the plan view of Fig. 1.

[0069] As usual, the knitted fabric layers 1 have successive stitches in a production direction P with an average stitch spacing a, wherein the knitted fabric layers have openings 3 (see in particular Fig. 2).

[0070] As will be apparent from the following explanations, the spacer fabric shown in Fig. 1 has a repeat length of twelve stitches, meaning that the same structure is obtained again after twelve stitches.

[0071]

[0072] From this, it can also be seen from Fig. 1 that the openings 3 extend along a production direction P over a length I which is more than twice the average mesh spacing a. As can also be estimated from Fig. 1, the length I can be, for example, between 5a and 10a.

[0073] According to Fig. 2, the openings 3 of the two knitted fabric layers 1 can be seen separately from one another. However, in the plan view according to Fig. 1, the openings 3 of the two knitted fabric layers 1 are arranged essentially in mutual overlap, so that corresponding pairs of openings 4 are visible in the plan view.

[0074] It can be seen that for each pair of openings 4, exactly one pair 5 of intersecting spacer thread sections 6 is provided, extending across the transverse direction Q of the openings 3. The spacer thread sections 6 intersecting at the pairs of openings 4 extend at an angle of approximately 45° relative to the knitted fabric layers 1.

[0075] At each pair of openings 4, the pair 5 of crossing spacer thread sections 6 is located in the middle of the corresponding pair of openings 4 with respect to the production direction P. The spacer thread sections 6 crossing 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.

[0076] It is already evident in Figures 1 and 2 that the openings 3 in the knitted fabric layers 1 are delimited by webs 7 formed from wales, a preferred knitting pattern being explained in detail below.

[0077]

[0078] In this context, Fig. 3 shows a drawing-in scheme for six guide rails L1 to L6 in order to be able to form the spacer fabric shown in Figures 1 and 2.

[0079] The two knitted fabric layers 1 are formed on the one hand by the guide rails L1, L2 and on the other hand by the guide rails L5, L6. The spacer threads 2 are formed by the guide rails L3, L4, each with a 1 full and 1 empty thread. The 1 full and 1 empty threads are offset by one needle pitch for the two guide rails L3, L4.

[0080] Figure 4 shows the laying pattern of the spacer threads 2, with a repeat length of twelve stitch rows. However, it should be noted that the spacer threads 2 are integrated into both knitted fabric layers 1 and are thus connected to each of the two knitted fabric layers in each stitch row.

[0081] From Fig. 4 it can be seen that the spacer threads 4 run largely straight in the production direction P and thus an I-fold is provided there. For every third stitch (related to the knitted fabric layers 1), a slant laying of the spacer threads 2 formed by both laying rails L3, L4 is provided, resulting in a crossing. These crossings are then located alternately on the one hand at the openings 3 and on the other hand at two immediately adjacent webs 7. These second crossings are accordingly not perceptible in Figures 1 and 2, but likewise lead to an advantageous improvement in the spacer fabric.

[0082] The proportion of spacer thread sections in I-lay to spacer thread sections in slanted lay is thus 5:1 in the illustrated embodiment.

[0083]

[0084] The two knitted fabric layers 1 are of identical design, with Fig. 5 showing the knitting pattern for both knitted fabric layers 1. For each of the two knitted fabric layers 1, a laying rail L2, L5 is provided, which, when fully drawn in, creates fringe wales by laying fringe. A further laying rail L1, L6, each with a 1 full, 1 empty draw, is assigned to a second thread system, which forms a partial weft, wherein adjacent fringe wales formed by the first thread system are connected to one another by the partial weft to form the openings 3.

[0085] Fig. 6A shows an example of a deformation-stress diagram for a spacer fabric according to the invention, with Figs. 6B and 6C showing corresponding diagrams for spacer fabrics from the prior art.

[0086] In the deformation-stress diagrams, an initial deformation is shown, which, however, is not relevant for the subsequent behavior of the spacer fabric, because only during the first deformation do strongly increased stress values ​​occur in spacer fabrics.

[0087] After repeated deformations, a constant behavior is established, for which a corresponding curve is shown in Figures 6A to 6C, to which the following explanations refer.

[0088] When determining the deformation-stress diagrams, a deformation of up to 70% of the total thickness occurs, after which the load is removed. Fig. 6A shows that a particularly uniform compression behavior results. At the beginning of a compression

[0089] the tension initially increases slowly and then evenly before the gradient decreases again before reaching the maximum compression of 70%.

[0090] Figure 6B shows the strain-stress diagram for a prior art spacer fabric. This spacer fabric contains, in addition to other yarns, a melt-bonded yarn, which is at least partially melted during production. The melt-bonded yarn contributes to a certain degree of permanent stabilization at certain points of the spacer fabric. The spacer fabric is particularly hard during the first deformation, and the initial deformations break individual bonds formed by the melt-bonded yarn.

[0091] After several deformations, a relatively steep increase in stress is observed after a soft initial area, giving the user the impression of a comparatively hard material. This is followed by a relatively flat area, before a steeper increase is observed upon reaching the maximum deformation of 70%, which may indicate the beginning of a blocky state.

[0092] According to Fig. 6C, another spacer fabric according to the prior art exhibits behavior similar to that shown in Fig. 6B. The tension increases relatively steeply over a comparatively short distance before reaching a plateau. Additional compression then leads to only a very limited increase in tension. Only before the maximum compression of 70% is reached does an increasing gradient occur again. The middle section of the curve can be perceived by the user as a kind of "dead zone," which is unpleasant.

Claims

Patent claims:

1. A spacer fabric with two knitted fabric layers (1) and spacer threads (2) connecting the knitted fabric layers (1), wherein the knitted fabric layers (1) have stitches following one another in a production direction (P) with an average stitch spacing a, wherein the knitted fabric layers (1) have openings (3) which extend along the production direction (P) over a length I, wherein the length I is more than 2*a and wherein the openings (3) of the two knitted fabric layers (1) are arranged essentially in mutual overlap and accordingly form opening pairs (4), characterized in that at least some of the opening pairs (4) are each provided with at least one pair (5) of intersecting spacer thread sections (6) extending across a transverse direction (Q) of the openings (3), wherein at these opening pairs (4) a number of pairs (5) of intersecting spacer thread sections (6) is less than l / 2a.

2. Spacer fabric according to claim 1, characterized in that at least one pair (5) of intersecting spacer thread sections (6) extending across the transverse direction (Q) of the openings (3) are provided at each of the pairs of openings (4).

3. Spacer fabric according to claim 1 or 2, characterized in that exactly one pair (5) of intersecting spacer thread sections (6) extending across the transverse direction (Q) of the openings (3) is provided at the corresponding pairs of openings (4).

4. A 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 pairs of openings (4) with respect to the production direction (p).

5. Spacer fabric according to one of claims 1 to 4, characterized in that the length I of the openings (3) is between 3*a and 12*a, in particular between 5*a and 10*a.

6. A spacer fabric according to any one of claims 1 to 5, characterized in that the openings (3) are delimited by webs (7) formed from wales, wherein spacer thread sections connecting adjacent wales are provided on the webs (7).

7. Spacer fabric according to one of claims 1 to 6, characterized in that the spacer threads (2) are knitted in a combined I-lay and slant lay, the proportion of spacer thread sections in I-lay to spacer thread sections in slant lay being 3:1 to 12:1, in particular 4:1 to 6:

1.

8. 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 a draw-in 1 full, 1 empty.

9. Knitted spacer fabric according to one of claims 1 to 8, characterized in that the two knitted fabric layers (1) have an identical lay.

10. Spacer fabric according to one of claims 1 to 9, characterized in that the knitted fabric layers (1) are each formed with two laying rails (L1, L2; L5, L6).

11. Spacer fabric according to one of claims 1 to 10, characterized in that at least one of the knitted fabric layers (1) comprises a first thread system with a fringe lay and a second thread system with a partial weft wherein adjacent fringe rods formed by the first thread system are connected by the partial weft to form the openings (3).

12. A spacer fabric according to one of claims 1 to 11, characterized in that a total thickness is between 5 mm and 40 mm.

13. Spacer fabric according to one of claims 1 to 12, characterized in that the average mesh spacing a is between 1 mm and 3 mm.

14. A spacer fabric according to any one of claims 1 to 13, characterized in that the spacer thread sections (6) crossing at the pairs of openings (4) extend at an angle of between 25° and 65°, in particular between 35° and 55°, relative to the knitted fabric layers (1).

15. Upholstery arrangement, in particular a climate-controlled seat for a motor vehicle, comprising a cover layer and a spacer fabric according to one of claims 1 to 14 arranged below the cover layer as a fluid distribution layer.

Images