Fabric and associated manufacturing process

Abstract

The invention relates to a fabric comprising: - an upper layer, comprising warp and weft yarns, defining a right-side surface of the fabric; - a lower layer, comprising warp and weft yarns, defining a wrong-side surface of the fabric; - a median plane, disposed between the upper and lower layers; and - a central layer, disposed on either side of the median plane, comprising at least some binding warp and / or weft yarns. This fabric is particular in that the binding yarns are configured to maintain a certain distance between the median plane and the right-side and / or wrong-side surface, said distance varying along the warp direction of the fabric and / or along the weft direction of the fabric, so as to form a relief on a surface of the fabric. The present invention also relates to a method for manufacturing a fabric according to the invention. Figure for the abstract: Fig 1

Description

Title of the invention: Fabric and associated manufacturing process technical field

[0001] The present invention relates to the field of weaving. More particularly, it relates to a fabric having raised patterns created by weaving on at least one of its outer surfaces, and a method for manufacturing such a fabric. The fabric according to the invention can be used for products in various fields, for example in clothing, furniture, leather goods, jewelry, watchmaking, vehicle interior decoration, etc. Previous technique

[0002] Weaving is a manufacturing process used to obtain fabric from textile yarns. During weaving, two sets of yarns are interlaced perpendicularly: the warp yarns, which run lengthwise in the direction of the weave, and the weft yarns, which pass through the warp yarns. The way in which the yarns are interlaced is called the weave.

[0003] Several techniques exist for creating a relief on the surface of a fabric by weaving technique.

[0004] One solution involves weaving with several yarns of very different thicknesses (or counts). Thus, a succession of fine warp yarns surrounding a few thicker warp yarns makes it possible to create slight reliefs on the fabric surfaces. This variation in yarn thickness can be done in either the warp or weft direction of the fabric. This method only allows for the creation of reliefs of small amplitude, and the shapes of these reliefs are limited to linear forms in the warp or weft.

[0005] A second method allows for the creation of textured effects by varying the weave in different areas of the fabric. This variation in weave is combined with a variation in the tension of the warp threads during weaving, and possibly the weft threads as well. This method makes it possible to obtain slight undulations on the surface of a fabric. This method is not suitable for creating textures other than embossed or wavy effects, and the variations on the reverse and front sides of the fabric are generally linked.

[0006] A third method for creating surface relief on a fabric is to arrange the threads transversely to the fabric surface. This is the technique of velvet weaves. The relief can be linear, to form a corduroy, or other shapes can be generated if the velvet is woven on a Jacquard loom allowing individual thread control. Two types of technology exist: warp velvet, in which the velvet pile is created by warp threads, and weft velvet, in which the velvet pile is created by weft threads. In In the case of warp velvets, if the pile loop is not cut, a looped fabric is obtained. The loops then allow for the creation of the desired texture. The drawback of these techniques is that the appearance of the fabric is altered in the textured areas, whether this texture is formed by the pile or the loops. The weave pattern beneath the loops or pile is then invisible. Description of the invention

[0007] The present invention aims to overcome these drawbacks by proposing a fabric comprising: - a top layer, comprising warp and weft threads, defining the right-side surface of the fabric, - a lower layer, comprising warp and weft threads, defining the reverse side of the fabric, - a median plane, arranged between the upper layer and the lower layer, and - a central layer, arranged on either side of the median plane, comprising at least some warp and / or weft binding threads.

[0008] This fabric is particular in that the binding yarns are configured to maintain a certain distance between the median plane and the front surface and / or the back surface, said distance varying according to the warp direction of the fabric and / or according to the weft direction of the fabric, so as to form a relief on the front and / or back surface.

[0009] Thanks to these arrangements, a wide variety of reliefs can be obtained precisely, on one or both sides of the fabric, solely by weaving techniques, the fabric being able to be manufactured with existing looms.

[0010] The binding yarns can be configured to maintain a first distance between the median plane and the front surface, and a second distance between the median plane and the back surface, said first and second distances varying according to the warp direction of the fabric, and according to the weft direction of the fabric, the first and second distances varying differently from each other, so as to form reliefs on the front surface and on the back surface not symmetrical with respect to the median plane, which allows the reliefs formed on the front surface of the fabric to be independent of the reliefs formed on the back surface of the fabric.

[0011] The upper layer and / or the lower layer may have at least two superimposed warp yarns and at least two superimposed weft yarns, which allows one layer to have the function of giving a certain appearance to the surface of the fabric, and the other layer to have a technical function of keeping the binding yarn in its sheath, which allows on one side to have an appearance with fewer defects, and on the other a better mechanical hold of the reliefs generated by the binding yarn on the reverse and / or front surfaces.

[0012] The binding threads can make round trips between the upper and lower layers, the variation of the distance between the median plane and the front or back surface corresponding to the variation of the length of the round trips of the binding threads from the median plane, which is a simple and effective means of implementing the invention.

[0013] The space between two consecutive back-and-forth movements made by the binding chains between the upper and lower layers can vary in the warp direction of the fabric and / or in the weft direction of the fabric, which makes it possible either to obtain a variable crush resistance on at least one of the fabric surfaces, or to maintain a constant crush resistance despite the reliefs.

[0014] The binding yarns can have a higher second moment of area than the other warp yarns of the fabric and the weft yarns of the fabric, which allows them to be more rigid, and therefore to effectively fulfill their role of generating reliefs on at least one of the surfaces of the fabric over time.

[0015] Said fabric may include at least one intercalated warp and / or weft yarn, arranged predominantly in standby between the front surface and the back surface, and occasionally protruding at the level of the front and / or back surface when the angle between the front surface, respectively back surface, has an angle of greater amplitude than a certain threshold with respect to the median plane, in order to compensate for the variations in spacing between the warp and / or weft yarns caused by this angle, and thus to avoid defects in the appearance of the fabric in areas having such an angle.

[0016] The present invention also relates to a method for manufacturing a fabric according to the invention, in which a loom is used comprising a plurality of heddles, each heddle comprising an eyelet, among which a first group of heddles, the eyelets of which are passed through by the warp threads of the upper layer, a second group of heddles, the eyelets of which are passed through by the warp threads of the lower layer, and a third group of heddles, the eyelets of which are passed through by the warp threads of the middle layer, said method characterized in that it comprises the following steps repeated cyclically: - opening of the crowd, during which: . in the first group of smooths, the eyelets of a first subgroup are placed in a high position, above the median plane, and the eyelets of a second subgroup are placed in an intermediate high position, between the median plane and the high position, and / or In the second group of smooths, the eyelets of a first subgroup are placed in a low position, below the median plane, and the eyelets of a second subgroup are placed in an intermediate low position, between the median plane and the low position, and . in the third group of smoothers, each of the eyelets is individually placed in a low position, a high position, a low intermediate position, or a high intermediate position, - insertion of at least one weft thread between the warp threads passing through the eyelets in the upper position and the warp threads passing through the eyelets in the intermediate upper position, and / or of at least one weft thread between the warp threads passing through the eyelets in the lower position and the warp threads passing through the eyelets in the intermediate lower position, - closing of the crowd, during which the eyelets previously placed in the high position are moved to the intermediate high position, and / or the eyelets previously placed in the low position are moved to the intermediate low position, and in that: - during at least one open-the-loom step, for at least one eyelet, the distance between the median plane and that eyelet in an intermediate high or low position is modified, relative to the previous open-the-loom step, in order to form a relief on the front or back surface, in the warp direction of the fabric, and / or - during at least one stage of opening the crowd, the distance between the median plane and the upper intermediate position is different for at least two eyelets in the upper intermediate position and / or the distance between the median plane and the lower intermediate position is different for at least two eyelets in the lower intermediate position, in order to form a relief on the front surface, respectively the back surface, in the weft direction of the fabric.

[0017] Thanks to these arrangements, a wide variety of reliefs can be obtained precisely, on one or both sides of the fabric, solely by weaving techniques, the fabric being able to be manufactured with existing looms.

[0018] The distance between the median plane and the intermediate low and / or high position can vary continuously: - during at least three successive stages of opening the crowd for a single eyelet, in order to form a continuous slope on at least one of the fabric surfaces in the warp direction, and / or - during a single stage of opening the swarm, for at least three eyelets crossed by consecutive warp threads in the weft direction, in order to form a continuous slope on at least one of the fabric surfaces in the weft direction, which is a simple and effective way of forming reliefs with continuous slopes on the surface of the fabric.

[0019] When an eyelet is in an intermediate low or high position, its position can be configured so that the warp thread passing through it, between this eyelet and the f-hole of the fabric, presents a correction angle with the median plane allowing to compensate for the return tension of the binding threads at the level of the weave and to obtain a defined distance between the median plane and the front or back surface of the fabric, which makes it possible to compensate for the tension and to precisely generate the desired relief on one or both sides of the fabric.

[0020] Said fabric manufacturing process may include a pre-step of determining the mathematical relationship for linking a distance between the median plane and the front or back surface to a correction angle value, comprising the following steps: - weaving according to a plurality of correction angles, until the distance between the median plane and the front or back surface stabilizes, - measurement of the distance between the median plane and the front or back surface, which constitutes a simple and effective means of implementing the invention.

[0021] The pre-step of determining the mathematical relationship that links a distance between the median plane and the front or back surface to a correction angle value can be repeated several times, by varying the spacing between two consecutive back-and-forth movements of the binding threads, in order to obtain a plurality of mathematical relationships that link a distance between the median plane and the front or back surface to a correction angle value, each mathematical relationship corresponding to a particular spacing between two consecutive back-and-forth movements of the binding threads, which makes it possible to obtain correction angles for different given situations, and thus to further improve the accuracy with which the reliefs are generated on the surface of the fabric.

[0022] The pre-step of determining the mathematical relationship that links a distance between the median plane and the front or back surface to a correction angle value can be repeated several times, by varying the weave of the fabric, in order to obtain a plurality of mathematical relationships that link a distance between the median plane and the front or back surface to a correction angle value, each mathematical relationship corresponding to a particular weave, which makes it possible to obtain correction angles for different given situations, and thus to further improve the accuracy with which the reliefs are generated on the surface of the fabric.

[0023] During the closing stage of the swarm, the eyelets in the upper position, respectively lower, can be moved to the intermediate upper position, respectively intermediate lower, one after the other in the weft direction, ending with the eyelets located on the side where the reserve of said weft yarn is located, which makes it possible to give the weft yarns the necessary length to travel over the reliefs of the fabric, and thus to avoid overtension problems.

[0024] The movement of each eyelet can be controlled by an individual motor, which makes it possible to generate a wide variety of reliefs on the surface of the fabric in the weft direction with precision. Brief description of the drawings

[0025] The present invention and its advantages will become more apparent from the following description of several embodiments given by way of non-limiting examples, with reference to the accompanying drawings, in which:

[0026] [Fig-1] [Fig. 1] is a schematic view of a fabric according to a particular embodiment of the invention, showing the relief of the surface from the front relative to its median plane,

[0027] [Fig.2] [Fig.2] is a schematic cross-sectional view along the plane parallel to the Z axis and to the weft direction of the fabric of [Fig.1],

[0028] [Fig.3] [Fig.3] is a schematic cross-sectional view along the plane parallel to the Z axis and to the warp direction of the fabric of [Fig.1],

[0029] [Fig.4] [Fig.4] is a schematic cross-sectional view along the plane parallel to the axis Z and to the warp direction of the weave of a fabric according to an example of an embodiment of the invention,

[0030] [Fig.5] [Fig.5] is a schematic cross-sectional view along the plane parallel to the Z axis and to the weft direction of the armor of [Fig.4],

[0031] [Fig.6] [Fig.6] is a schematic cross-sectional view along the plane parallel to the Z axis and to the weft direction of the weave of [Fig. 4], under different conditions of relief formed by the surfaces of the fabric,

[0032] [Fig.7] [Fig.7] is a schematic cross-sectional view along the plane parallel to the Z axis and to the weft direction of the weave of [Fig. 4], under different conditions of relief formed by the surfaces of the fabric, with the presence of intercalated threads,

[0033] [Fig.8] [Fig.8] is a schematic cross-sectional view along the plane parallel to the Z axis and to the chain direction of the fabric manufacturing process according to a preferred embodiment of the invention, when the crowd is open,

[0034] [Fig.9] [Fig.9] is a detailed view of one of [Fig.8],

[0035] [Fig. 10] [Fig. 10] is a schematic cross-sectional view along the plane parallel to the Z-axis and the weft direction of the fabric manufacturing process of [Fig. 8], when the swarm is open,

[0036] [Fig. 11] [Fig. 11] is a schematic cross-sectional view along the plane parallel to the Z axis and the weft direction of the fabric manufacturing process of [Fig. 8], when the swarm is being closed. Description of the implementation methods

[0037] In the illustrated embodiments, identical elements or parts bear the same reference numbers. Furthermore, terms with a relative meaning, such as vertical, horizontal, right, left, front, back, above, below, etc., should be interpreted under normal conditions of use of the invention, as shown in the figures. The X, Y, and Z axes are defined by an orthonormal coordinate system illustrated in [Fig. 1]. Moreover, the geometric positions indicated in the description and claims, such as "perpendicular," "parallel," and "symmetrical," are not limited to the strict geometric sense but extend to geometric positions that are close, i.e., that allow a certain tolerance within the technical field considered, without affecting the result obtained.This tolerance is notably introduced by the adverb "sensible", without this term necessarily being repeated before each adjective.

[0038] With reference to the figures, the fabric 1 according to the invention mainly comprises three layers: an upper layer 2, defining the front surface 3 of the fabric 1, a lower layer 4, defining the back surface 5 of the fabric 1, and a middle layer 6.

[0039] The terms "lower" and "upper" used to define layers 2, 3 are used only to facilitate understanding of the present description in relation to the accompanying figures, on which the upper layer 2 is generally shown above the lower layer 3. However, the fabric can of course be turned over, and present its right side surface 3 above its wrong side surface 5.

[0040] The upper layer 2 and the lower layer 4 each comprise warp yarns 7 and weft yarns 8, woven together in a weave. The weave may be uniform throughout the upper layer 2, or different weaves may be used in different areas of the upper layer 2. The weave may be uniform throughout the lower layer 4, or different weaves may be used in different areas of the lower layer 4. The weave or weaves used in the upper layer 2 may be the same as, or different from, the weave or weaves used in the lower layer 4.

[0041] The fabric 1 has a median plane 9, situated between the upper layer 2 and the lower layer 4. During weaving, which is described later, the warp threads pass through the eyelets of the heddles before being woven, and then join the fabric's weft. The median plane 9 is the plane through which the warp threads pass when the eyelets are arranged so that the path of the warp threads is straight in the vicinity of the eyelets, that is, when the eyelets do not exert pressure on the warp threads that would alter their path. In other words, the median plane 9 is the plane through which the warp threads would pass if they did not pass through the eyelets. The median plane 9 is generally horizontal during weaving, and it is used as a geometric reference to define the position of the eyelets throughout the weaving process, as described later. After weaving, fabric 1 can of course be deformed, and the set of points of fabric 1 that were in the median plane 9 during weaving is then designated as the "median plane".

[0042] The central layer 6 extends on either side of the median plane 9. The central layer 6 lies at least partially between the upper layer 2 and the lower layer 4. Indeed, to link the upper layer 2, lower layer 4, and the central layer 6 together, some weft and / or warp yarns of the upper layer 2, lower layer 4, or of the central layer 6, may interlace with the warp and / or weft yarns of the adjacent layer. The central layer 6 therefore does not extend strictly between the upper layer 2 and the lower layer 4. Figures 4 and 5 illustrate, for example, the fact that layers 2, 4, and 6 may intersect along the Z-axis. In these figures, the dimensions of this intersection are exaggerated to clearly visualize the linking of the layers together. However, the central layer 6 extends, in most cases, for the most part, between the upper layer 2 and the lower layer 4.It is therefore through the central layer 6 that the upper layer 2 and lower layer 4 are mechanically linked together.

[0043] Fig. 2, respectively 3, shows tissue 1 in cross-section, with three upper layers 2 and lower layers 4, each corresponding to a distinct depth along the X axis, respectively the Y axis.

[0044] The central layer 6 comprises binding yarns 10, which may be weft yarns or warp yarns. However, it is preferable that the central layer 6 include at least one layer of warp yarns. If at least some of the binding yarns 10 are warp yarns, the central layer 6 may consist only of these binding yarns 10. Conversely, if the binding yarns 10 are exclusively weft yarns, the central layer 6 preferably also includes warp yarns.

[0045] The binding yarns 10 serve to maintain a certain distance between the median plane 9 and the front and / or back surface. This distance can vary along the warp and / or weft direction of the fabric 1, so as to create a relief on the front and / or back surface. Preferably, this distance varies along both the warp and weft directions of the fabric 1, in order to create reliefs that can take on complex, non-linear shapes. For example, in the example shown in [Fig. 3], the binding yarn 10, which is a warp yarn, maintains a distance between the warp yarns 7 of the upper layer 2 and the median plane 9, and between the warp yarns 7 of the lower layer 4 and the median plane 9.

[0046] The fabric 1 thus has a variable thickness, as shown by way of example in Figures 1 to 3. The X-axis corresponds to the warp direction, i.e., parallel to the warp yarns 7, and the Y-axis corresponds to the weft direction, i.e., parallel to the weft threads 8. The thickness of the fabric 1, and the surface reliefs it has, extend along the Z axis, which is perpendicular to the X and Y axes. This thickness varies depending on the position considered along the X and Y axes. The fabric 1 therefore has at least one relief on at least one of its two surfaces 3 and 5, in order to obtain a topography offering, for example, a certain aesthetic appeal. The reliefs present on the front surface 3 and on the back surface 5 may coincide with each other, for example with a symmetry about the median plane 9, or in such a way that the surfaces 3 and 5 are parallel to each other. The reliefs present on the front surface 3 and on the back surface 5 may also not coincide with each other, the present invention allowing for great freedom in the design of the fabric 1.

[0047] Thus, we can define a first distance, respectively second distance, between the median plane 9 and the front surface 3, respectively the back surface 5. The first distance and the second distance are each variable in the plane formed by the axes X and Y, in other words in the warp and weft directions of the fabric 1. We can predict that the first distance and the second distance vary independently of each other, thus generating reliefs on the front surface 3 and the back surface 5 which are not symmetrical with each other.

[0048] In the example shown in [Fig. 3], it can be observed that the space defined by the back-and-forth movements of the binding yarn 10 between the upper layer 2 and the lower layer 4 can vary along the X-axis, allowing for relief along the direction of the binding yarn 10, that is, in this figure, along the warp direction. In this example, relief along the weft direction can be produced by the fact that each back-and-forth movement of a warp binding yarn 10 can have a different shape.

[0049] The back-and-forth movements of the binding thread 10 define a three-dimensional envelope 11 occupied by the central layer 6, from which any reliefs on the surfaces 3, 5 are derived.

[0050] In other embodiments, the binding yarns 10 are weft yarns. Each binding yarn 10 then makes it possible to produce relief in the weft direction, and the fact that each binding yarn 10 evolves independently of the others makes it possible to produce relief in the warp direction.

[0051] Whether the binding yarns 10 are warp yarns, weft yarns, or whether the fabric comprises both warp and weft binding yarns 10, the density of the binding 10 may differ from the density of the upper 2 and lower 3 layers. The fabric 1 may, for example, have fewer binding yarns 10 in the warp, respectively in the weft, than warp yarns 7, respectively weft yarns 8 on the upper 2 and / or lower 3 layer. For example, one warp yarn may be provided for every two warp yarns 7 or weft yarns 8.

[0052] As illustrated by way of example in Figures 4 to 7, the upper layer 2 and / or the lower layer 4 is preferably of multilayer composition, that is to say, it comprises at least two layers of warp yarns 7 superimposed along the Z-axis, and at least two layers of weft yarns 8 superimposed along the Z-axis. The warp yarn levels 7 and weft yarn levels 8 are then preferably superimposed sympathetically, that is to say, without crossing along the Z-axis. Figures 4 and 5 illustrate, for example, a fabric 1 comprising, on each of its lower layer 2 and upper layer 4, two layers of warp yarns 7 and two layers of warp yarns 8. The multilayer compositions allow the use of different yarns 7, 8 for different functions, both in the upper layer 2 and in the lower layer 4.Some yarns 7, 8, which are usually exposed on the front and / or back surface 5, can be used to give the fabric 1 its appearance and contribute to its aesthetic appeal. Other yarns 7, 8, which are usually, or even always, hidden within the fabric 1, can provide technical functions, for example, holding the central layer 6, and in particular the binding yarns 10, within its sheath 11, joining the upper layer 2 and lower layer 4 to the central layer 6 by interlacing their respective yarns, or giving the fabric 1 a certain thickness, mechanical strength, or other properties. The binding yarns 10 are held in the warp primarily by the weft yarns 8, while the binding yarns 10 are held in the weft primarily by the warp yarns 7.This separation allows us to maintain a very clean front 3 and / or back 5 surface, without appearance defects linked to differences in rigidity between the binding threads 10 and the other threads 7, 8 of the fabric 1. .

[0053] As illustrated by way of example in [Fig. 3], the binding yarns 10 can move back and forth between the upper layer 2 and the lower layer 4. This also applies to a weft binding yarn 10. These back-and-forth movements do not preclude crossings with warp yarns 7 and / or weft yarns 8 of the upper layer 2 and / or lower layer 3, which may be necessary to bind the upper layer 2 and lower layer 3 with the central layer 6.

[0054] In this embodiment, the back-and-forth movements made by the binding threads 10 can be more or less long, and it is the length of these back-and-forth movements that allows the distance between the median plane 9 and the front surface 3, respectively the back surface 5, to be varied. More precisely, the variation in length at the level of the portion of these back-and-forth movements located between the median plane 9 and the upper layer 2, respectively lower layer 4, and the front surface 3, respectively the back surface 5, allows the distance between the median plane 9 and the front surface 3, respectively the back surface 5, to be varied. This therefore makes it possible to generate the reliefs on the front surface 3 and the back surface 5 independently.

[0055] When the binding yarn 10 moves back and forth between the upper layer 2 and the lower layer 4, it is also possible to vary the spacing between two consecutive back-and-forth movements of the binding yarn 10, whether it is a warp or weft binding yarn 10. In some embodiments, this variation can be used to generate variable crush resistance in different areas of the fabric, to provide a changing tactile experience. Conversely, in other embodiments, or in other areas of the fabric 1, this variation makes it possible to compensate for variations in the length of the back-and-forth movements of the warp yarns 10 in order to maintain constant crush resistance over the entire fabric 1 or over an entire area of ​​the fabric 1. Finally, this variation in the spacing between two back-and-forth movements can be used to provide the mechanical strength to the fabric 1 necessary to withstand an abrupt change in relief on a surface 3, 5 of the fabric 1..

[0056] The binding yarns 10 preferably have a higher second moment of area than the other warp yarns 7 and weft yarns 8 of the fabric 1. This makes it possible to reduce the influence of the forces produced by the other yarns on the binding yarns 10, particularly during buckling, so that the shape of the binding yarns 10, and thus the reliefs they produce on at least one of the surfaces 3, 5 of the fabric 1, are better preserved.

[0057] Figures 4 and 5 illustrate an example of a fabric weave according to the invention. In this example, the upper layer 2 and lower layer 4 each comprise two overlapping warp yarns 7 and two overlapping weft yarns 8. The middle layer 6 comprises a binding yarn 10 in the warp. The overlapping warp yarns 7 and weft yarns 8 do not intersect; this is therefore a case of sympathetic binding construction, both for the upper layer 2 and the lower layer 4, and for their interlacing with the middle layer 6. In [Fig. 5], the dashed lines represent the binding yarns 10 connecting the upper layer 2 and lower layer 4. In the example shown, [Fig. 4] observes that there is only one back-and-forth pass of the binding yarn 10 per weave cycle. In other embodiments, however, two or more passes of the binding yarn 10 can be implemented per weave cycle, whether this binding yarn 10 is a warp or weft yarn..

[0058] As shown in the example in [Fig. 5], it is preferable for the weft yarns 8 located on the surface to move progressively, that is, by descending and ascending one warp yarn 7 after the other, without plunging under two, for example. This allows for a better aesthetic appearance of the fabric 1.

[0059] An infinite number of other weaves can of course be used within the framework of the present invention, by varying the number of warp and weft yarns superimposed in each layer 2, 4, 6, and their interlacing patterns. A greater number of superimposed yarns allows, for example, more complex color arrangements, and we can use a level of a thread 7, 8 of a certain color, which remains hidden over almost the entire fabric 1, and emerges on the surface 3, 5 punctually.

[0060] Figure 6 illustrates an example of fabric 1 using the weave of Figure 5 in areas of fabric 1 exhibiting non-concurrent reliefs on its two surfaces 3 and 5. On the weave shown near the origin of the coordinate system in Figure 6, the curves followed by the surfaces 3 and 5 of fabric 1 have relatively small angles with the Z-axis. For this type of relief, where the angles are, for example, less than or equal to a threshold between 25 and 40°, for example 30°, it can be predicted that the surface appearance of fabric 1 is only slightly, or not at all, affected by the relief.

[0061] On the weave shown at a distance from the origin of the coordinate system, on the contrary, the curves followed by the surfaces 3, 5 of fabric 1 exhibit relatively large angles with the Z-axis. For this type of relief, where the angles are greater than or equal to the aforementioned threshold, it is possible that in certain embodiments, depending on the weave, the type of yarns used, etc., the surface appearance of fabric 1 may be affected by the relief. In this latter case, it is possible that surface defects may appear. More precisely, in [Fig. 6], it can be seen that certain weft 8 and warp 7 yarns, which are normally hidden under the surface weft 8 and warp 7 yarns, will be much more visible on the weave of fabric 1 located at a distance from the origin of the coordinate system than on the weave of fabric 1 located near the origin of the coordinate system.This is explained by the fact that the warp threads 7 are positioned at well-defined locations in the weft direction (on the x-axis of the coordinate system in [Fig. 6]), and can only move very slightly in this direction. Various methods can be implemented to solve this problem.

[0062] A first method is to design the fabric 1 with a high saturation ratio, for example greater than 1.3, for the weft yarns 7 and 8 located on the front surface 3 and / or the back surface 5. A high saturation ratio corresponds to yarns being very tightly packed together, i.e., a large number of yarns per cm, in the direction transverse to the yarns. This allows that in the event of a separation of the surface yarns generated by a large angle between the surface 3, 5 and the median plane 9, as seen in [Fig. 6], the excess space generated by the evolution of the curves of the two surfaces can be compensated for by this saturation. This technique only works for separations between the surface yarns 7, 8 that are not too large, therefore for reliefs that do not have excessively large angles with respect to the median plane 9.

[0063] A second method, which can be combined with the first method, is to use a surface weave with floats, preferably at least three, in the weft. Such weft yarns 8 remain above or below several consecutive warp yarns 7, making it possible to mask changes in the spacing of the weft yarns 8.

[0064] In a third method, an example of which is shown in [Fig. 7], the fabric 1 has intercalated yarns 12a, 12b. The intercalated yarns 12a, 12b, shown in warp in [Fig. 7] but which can also be arranged in weft, are mostly positioned invisibly within the fabric 1, as in [Fig. 7] the intercalated yarn in position 12a. When it is necessary to use them, the weave changes locally to allow the intercalated yarns in position 12b to be brought up to the surface 3, 5 of the fabric 1. The references 12a, 12b therefore designate the same intercalated yarns, which are in some places in fabric 1 in position 12a, and in other places in position 12b. This bringing up is illustrated by a dashed arrow in [Fig. 7]. The interlayer wires 12a, 12b, when they are standing still, can be in the middle layer 6, or in one of the upper layers 2 or lower layers 4.

[0065] The warp 7 and weft 8 yarns may all be identical, or may differ depending on whether they are warp 7 or weft 8 yarns, their position in the weave of fabric 1, or the area of ​​fabric 1 they occupy. All yarn architectures may be used, for example: fiber yarns, twisted yarns, multifilament yarns, wrapped yarns, fancy yarns. All materials may be used, for example: natural, thermoplastic, thermosetting, metallic.

[0066] When the lower layer 2 or upper layer 4 comprises several superimposed layers of yarns 7, 8, the yarns 7, 8 protruding from the front surface 3 and / or back surface 5 preferably have a count, expressed in Tex, greater than or equal to the count of the yarns 7, 8 located below the surface. This reduces the risk of over-saturation of the inner layer of yarns 7, 8 relative to the surface yarns 7, 8, which could lead to surface defects.

[0067] The binding yarns 10, for their part, are preferably composed of monofilament yarns, allowing for good rigidity. These monofilaments must have a diameter no more than the other yarns 7, 8, or even preferably smaller than the other yarns 7, 8 of the fabric 1, in order to reduce the risks of over-saturation of the central layer, and therefore of surface defects 3, 5 of the fabric 1, these risks being all the more important as the binding yarns 10, being mostly more rigid, compress little.

[0068] Fabric 1 can be manufactured using a loom as shown in [Fig. 8]. Such a loom has heddles, each with an opening called an eyelet 13a, 13b, 13c, 13d. The references 13a, 13b, 13c, 13d can refer to the same eyelets, which can be positioned 13a at certain points in the weaving process and 13b, 13c, or 13d at other points, as described below. The warp threads of fabric 1 pass through the eyelets 13a, 13b, 13c, 13d and are free to move translationally along the Z-axis, that is, in a direction perpendicular to the median plane 9. The warp threads, after passing through the eyelets 13a, 13b, 13c, 13d, pass through a comb, imposing a position in the weft direction of fabric 1 at the level of the weft 15 of fabric 1.

[0069] Three groups of heddles, and therefore of eyelets 13a, 13b, 13c, 13d, can be defined. The first group of heddles participates in the making of the upper layer 2, the eyelets 13a, 13c of the heddles in this group being crossed by the warp threads 7 of the upper layer 2. The second group of heddles participates in the making of the lower layer 4, the eyelets 13b, 13d of the heddles in this group being crossed by the warp threads 7 of the lower layer 4. The third group of heddles participates in the making of the middle layer 6, the eyelets 13a, 13b, 13c, 13d of the heddles in this group being crossed by the warp threads of the middle layer, which may or may not be binding threads 10.

[0070] The manufacturing process then comprises successive steps of opening the swarm, inserting at least one weft yarn into the swarm, and then closing the swarm.

[0071] Throughout the process, the eyelets 13a, 13b, 13c, 13d can each be placed in one of the following four positions, illustrated by way of example in Figures 8 and 12: a high position, located above the median plane, occupied by the eyelets 13a; an intermediate high position, located between the median plane 9 and the high position, occupied by the eyelets 13b; a low position, located below the median plane 9, occupied by the eyelets 13c; and an intermediate low position 9, located between the median plane and the low position, occupied by the eyelets 13d. Some eyelets 13, and in some cases all the eyelets 13, change position by following a translational movement perpendicular to the median plane during the opening and closing steps of the crowd.

[0072] During the opening of the sheaf, it can be opened for the first two groups of heddles, allowing simultaneous weaving of weft yarns 8 in the lower layer 2 and upper layer 4. This is particularly the case if the number of weft yarns 8 is the same in the lower layer 2 and upper layer 4. In other embodiments, or during other sheaf opening stages in the same manufacturing process, the sheaf may be opened only for the first or second group of heddles, and remain closed for the other. This allows for differentiated weaving on the lower layer 2 and upper layer 4, and, for example, a differentiated weft yarn density between these two layers.

[0073] Thus, the crowd opening step comprises at least one of the following sub-steps, and in some cases both of the following sub-steps: - some eyelets 13a of the first group are placed in a high position while other eyelets 13b of the first group are placed in an intermediate high position, - Some eyelets 13c of the second group are placed in a low position, while other eyelets 13d of the second group are placed in an intermediate low position.

[0074] During the sheaf opening step, each eyelet 13a, 13b, 13c, 13d of the third group can each be placed in one of the following positions, independently of each other, depending on the chosen weave: high position, low position, intermediate high position, and intermediate low position. If this step coincides with an interlacing of a weft yarn 8 of the upper layer 2, or lower layer 4, with a warp yarn of the middle layer 4, whether this warp yarn is a binding yarn 10 or not, at least one of the eyelets 13a, 13b, 13c, 13d of the third group will then be placed in a high position, or low position, respectively. It should be noted that in the case where the binding threads 10 are in the weft, it can be predicted that the warp threads of the central layer 6 do not cross the median plane.In this case, some eyelets 13a, 13b, 13c, 13d of the third group are arranged throughout the present process sometimes in a high position, sometimes in an intermediate high position, which allows them in some cases to ensure the connection with the lower layer 4, while other eyelets 13a, 13b, 13c, 13d of the third group are arranged throughout the present process sometimes in a low position, sometimes in an intermediate low position, which allows them in some cases to ensure the connection with the lower layer 4.

[0075] Once the sheath is open, an upper space 16a is defined between the warp threads 7 passing through the eyelets 13a in the upper position and the warp threads 7 passing through the eyelets 13b in the intermediate upper position, and / or a lower space 16b is defined between the warp threads 7 passing through the eyelets 13c in the lower position and the warp threads 7 passing through the eyelets 13d in the intermediate lower position. These spaces 16a, 16b are delimited in the weft direction on the one hand by the weft 15 of the fabric 1, and on the other hand by the plane in which the eyelets 13 are located.

[0076] The next step then consists of inserting at least one weft yarn 8 into one or both of these spaces. The number of weft yarns 8 inserted into each space depends, of course, on the weave of the fabric 1, with regard to the top layer 2, the bottom layer 4, and the middle layer 6. The insertion of the weft yarns 8 can be done by shuttle 17, or by spear, or by any other insertion method.

[0077] Once the weft threads 8 are inserted, the sheaf is then closed, i.e. the eyelets 13a which were placed in the upper position are brought back to the intermediate upper position, and the eyelets 13c which were placed in the lower position are brought back to the intermediate lower position.

[0078] The process described above can be used to weave a fabric 1 comprising several layers of weft yarns 8 and warp yarns 7 superimposed along the Z-axis, at the level of the upper layer 2 and / or at the level of the lower layer 4. For To do this, the overlapping warp threads, arranged at the same level in the weft direction, are placed in the same groove of the loom's reed. Then, during the actual weaving process, the weft thread 8 closest to the median plane 9 is inserted first, and then, during the next opening of the sheaf, the weft 15 of the fabric 1 is not shifted in the warp direction.

[0079] In the above process, steps corresponding to a three-part sheaf opening have been described, with two possible spaces for weft yarn insertion. However, the invention can be carried out with a loom allowing a five-part sheaf opening, with four or more possible spaces for weft yarn insertion. A process using a loom allowing a five-part sheaf opening makes it possible to simultaneously insert two levels of weft yarns for each of the upper 2 and lower 4 layers, thus saving time in the production of multilayer fabrics. In the case of a three-part sheaf opening, which

[0080] The lower and upper intermediate positions, although each designated above by a unique name, are variable in order to generate the relief on the surface 3, 5 of the fabric 1. Indeed, variations in the lower and upper intermediate positions allow for the generation of the envelope 11 occupied by the binding thread 10, from which the relief is derived. Depending on the type of relief desired, two methods of varying the intermediate positions can be used, either individually or in combination. The lower and upper intermediate positions are always at a non-zero distance from the median plane 9, to provide space for the binding thread 10. In fact, if the lower and upper intermediate positions were permanently aligned with the median plane, a conventional, non-relief fabric would be obtained.

[0081] In a first mode, the variation of intermediate positions is temporal and allows for the generation of a relief in the warp direction of the fabric 1. To achieve this, the lower or upper intermediate position of an eyelet can vary over time and differ according to distinct stages of the swarm opening. This concerns at least one eyelet, but preferably a plurality of eyelets. This variation may occur only between two consecutive stages of the swarm opening, but it preferably occurs between several pairs of consecutive swarm opening stages. If the lower intermediate position is involved, then the relief is generated on the reverse side surface 5, and if the upper intermediate position is involved, the relief is generated on the front side surface 3.

[0082] Preferably, in this first mode, the distance between the median plane and the intermediate low and / or high position is continuously varied during at least three successive stages of opening the swath. This variation involves at least one eyelet 13, and preferably a plurality of eyelets 13. This makes it possible to form a continuous slope on one of the surfaces 3, 5 of the fabric in the warp direction.

[0083] To implement this first mode, a loom is preferably used which allows the height of the eyelets 13a, 13b, 13c, 13d to be positioned precisely without positional constraints along the Z axis, for example with an accuracy between 0.1 and 0.5 mm, and the intermediate distances of the eyelets 13a, 13b, 13c, 13d can vary over a distance between 10 and 40 cm.

[0084] In a second mode, the variation of intermediate positions occurs along the weft direction of fabric 1, generating a relief in the weft direction of fabric 1. To achieve this, the lower or upper intermediate position of several eyelets differs during the same swarm opening step, as illustrated in [Fig. 1 1]. This variation preferably occurs during several swarm opening steps, and in particular several consecutive steps, to create reliefs on the right side 3 and / or wrong side 5 surface extending in the warp and weft directions. If the lower intermediate position is involved, then the relief is generated on the wrong side 5 surface, and if the upper intermediate position is involved, the relief is generated on the right side 3 surface.

[0085] It should be noted that what is referred to in this description as the position of an eyelet 13 corresponds to the area of ​​the eyelet 13a, 13b, 13c, 13d through which the warp thread passes. As shown in [Fig. 8], this position corresponds to the lower end of the eyelet 13a, 13b, 13c, 13d for the high and upper intermediate positions, and the upper end of the eyelet 13a, 13b, 13c, 13d for the low and lower intermediate positions.

[0086] Preferably, in this second mode, the distance between the median plane and the intermediate low and / or high position is continuously varied for at least three eyelets crossed by consecutive warp yarns, that is, yarns belonging to the same warp yarn level. These warp yarns can be binding yarns 10, or warp yarns 7 belonging to the lower layer 2 or upper layer 4, or warp yarns belonging to the central layer 6 that are not binding yarns. This variation involves at least one sheaf opening stage, and preferably several sheaf opening stages. This makes it possible to form a continuous slope on one of the fabric surfaces 3, 5 in the weft direction.

[0087] To implement this first mode, a loom is preferably used that allows the movement of each eyelet 13a, 13b, 13c, 13d to be controlled by an individual motor, for example a servomotor, the movement and position of each eyelet 13a, 13b, 13c, 13d thus being totally independent of the movements of the other eyelets 13

[0088] The two modes described above can be combined to obtain reliefs taking complex forms in the warp and weft direction of fabric 1.

[0089] In the process according to the invention, the lengths absorbed by the warp threads of the fabric 1 vary considerably from one another, whether due to the weave itself or changing surface topographies. It is therefore preferable that the warp threads, both the warp threads 7 of the lower layer 2 and upper layer 4, and the warp threads of the middle layer 6, which may also be binding threads 10, be individually tensioned. This tensioning can be achieved by means of bobbins located at the rear of the loom. The bobbins are racks where the warp thread bobbins are placed. Weights, cup brakes, or motorized shafts allow the necessary tensions to be applied to the different warp threads, without these examples being limiting.

[0090] In the process according to the invention, the lower and upper intermediate positions are determined according to the desired relief on the front 3 or back surfaces. Schematically, the distances between the intermediate positions and the median plane 9 determine the three-dimensional envelope 11 occupied by the binding thread 10: the further the intermediate positions are from the median plane 9, the more space the binding thread 10 and its envelope 11 will occupy, and therefore the more pronounced the relief generated on the surfaces 3, 5 will be.

[0091] In a first approach, when it is desired to generate an envelope 11 of a given dimension, with a first distance above the median plane 9 and a second distance below the median plane 9, the eyelets can be arranged in an intermediate high position at the first distance from the median plane 9, and the eyelets in an intermediate low position at the second distance from the median plane 9. For example, if at the location of the weave 15 of the fabric 1, it is desired that the envelope 11 defined by the binding thread 10 rises up to 2.5 mm above the median plane 9 and up to 1 mm below the median plane, the eyelets 13b can be placed in an intermediate high position at 2.5 mm from the median plane 9, and the eyelets 13d in an intermediate low position at 1 mm from the median plane 9.

[0092] In a second approach, the intermediate low and high positions are further from the median plane 9 than the distance that we wish to generate between the ends of the sheath 11 of the binding wire 10 and the median plane 9. This additional distance E, represented in [Fig.

[10] In particular, with the guide curve 18 on which the eyelets 12b, 12d are placed, it is possible to take into account the restoring tension of the binding threads 10 at the level of the fold 15, and therefore to more precisely control the reliefs generated on the surfaces 3, 5. The additional distance 18 corresponds to the distance, along the Z-axis, between the upper or lower end of the envelope 11 occupied by the binding thread 10, and the eyelet 13b, 13d, and is determined independently for the lower intermediate position and the upper intermediate position, and independently for each eyelet 13b, 13d that occupies one of these positions, depending on the desired envelope 11 for the binding yarn 10. For each eyelet 13b, 13d, the additional spacing 18 corresponds to a correction angle α between the median plane 9 and the warp yarn passing through the eyelet 13b, 13d, considering the portion of this warp yarn located between the eyelet 13b, 13d and the weave 15 of the fabric 1. Indeed, it is at the angular level that the restoring tension of the binding yarn 10 must be compensated. This restoring tension depends on several parameters, notably the flexural rigidity of the binding yarns 10, and the weaves chosen for the binding yarn 10 and for the bonding of the binding yarn 10 with the lower 2 and upper 4 layers.

[0093] The determination of the correction angle α can be carried out during a pre-step prior to the weaving process, during which several correction angles α are determined, corresponding to desired distances between the median plane and the right side surface 3 or the wrong side surface 5. This pre-step can be carried out empirically, by performing weaving tests with a plurality of correction angles α, and determining for each the distance between the median plane 9 and the generated right side surface 3, or wrong side surface 5. Indeed, by weaving with a given low or high intermediate height, after a few weave cycles, this distance stabilizes and is independent of the initial height of the surface.Preferably, the results of these tests are used to establish a mathematical relationship using a regression model, allowing us to know with a satisfactory confidence index the correction angle a for any distance between the median plane and the front surface 3, or the back surface 5.

[0094] It should be noted that the relationship between the correction angle a and the distance between the median plane 9 and a surface 3, 5 woven with this correction angle depends on a number of factors: the type of binding yarn 10, the type of warp yarn 7 and weft yarn 8 of the lower layer 2 and upper layer 4, the weaves used at all levels of the fabric 1, the spacing between consecutive back-and-forth passes of the binding yarns 10, etc. All of these factors, taken together, constitute at each instant what can be called a weaving scenario. To weave with maximum precision, before proceeding with weaving, the pre-step described above is repeated as many times as the number of scenarios that will be used to weave fabric 1. In order to save time, one can choose to group together certain scenarios that are sufficiently similar, in particular because they have a number of identical or similar factors, and to perform only one pre-step per group of scenarios..

[0095] Once the correction angle to be implemented is known, the additional distance 18 can be determined with the following mathematical law: E = L x tan (a), with L the distance along the warp direction between the eyelet 13b, 13d and the fabric 15.

[0096] Preferably, during the swarm closing step, the eyelets 12a in the upper position are not all moved synchronously to the intermediate upper position, and / or the eyelets 12c in the lower position are not all moved synchronously to the intermediate lower position. It is preferable to introduce a phase shift for the different eyelets in these movements. Indeed, if they are all moved at the same time, in some cases, overvoltages can occur in the weft threads 8 of one of the lower layer 2, upper layer 4, or possibly the central layer 6, which have just been inserted. Therefore, a swarm closing step is preferred in which the eyelets 12a and 12c in the lower and upper positions, respectively, are moved one after the other, in the weft direction, ending with the eyelets 12 located on the side where the reserve of weft threads 8 that have just been inserted is located.Thus, a sufficient length of weft yarn is placed to absorb the contours of the fabric 1, and the risk of overtension problems is reduced.

[0097] When the weft threads are inserted using a shuttle system 17, the eyelet 13a, 13c located opposite the exit position of the shuttle 17 of the sheaf is closed first, as illustrated in [Fig. 11]. If, on the other hand, a spear system is used for weft insertion, with the slack in the thread located opposite the spear head, the sheaf will close progressively, starting with the eyelets 13a, 13c located closest to the exit position of the spear head of the sheaf.

[0098] The present invention is not limited to the embodiments described but extends to any modification and variant obvious to a person skilled in the art, within the limits of the appended claims. Furthermore, the technical features of the various embodiments and variants mentioned above may be combined, in whole or in part.

Claims

Demands

1. Fabric comprising: - an upper layer, comprising warp and weft yarns, defining a front surface of the fabric, - a lower layer, comprising warp and weft yarns, defining a back surface of the fabric, - a median plane, disposed between the upper and lower layers, and - a central layer, disposed on either side of the median plane, comprising at least some binding warp and / or weft yarns, characterized in that the binding yarns are configured to maintain a certain distance between the median plane and the front surface and / or the back surface, said distance varying along the warp direction of the fabric and / or along the weft direction of the fabric, so as to form a relief on the front and / or back surface.

2. Fabric according to claim 1, characterized in that the binding yarns are configured to maintain a first distance between the median plane and the front surface, and a second distance between the median plane and the back surface, said first and second distances varying along the warp direction of the fabric, and along the weft direction of the fabric, the first and second distances varying differently from each other, so as to form reliefs on the front surface and on the back surface not symmetrical with respect to the median plane.

3. Fabric according to any one of claims 1 or 2, characterized in that the top layer and / or the bottom layer comprises at least two superimposed warp yarns and at least two superimposed weft yarns.

4. Fabric according to any one of claims 1 to 3, characterized in that the binding yarns make back-and-forth movements between the upper and lower layers, the variation in the distance between the median plane and the front or back surface corresponding to the variation in the length of the back-and-forth movements of the binding yarns from the median plane.

5. Fabric according to claim 4, characterized in that the space between two consecutive back-and-forth movements made by the binding chains between The top and bottom layers vary in the warp direction of the fabric and / or in the weft direction of the fabric.

6. Fabric according to any one of claims 1 to 5, characterized in that the binding yarns have a higher second moment of area than the other warp yarns of the fabric and the weft yarns of the fabric.

7. Fabric according to any one of claims 1 to 6, characterized in that it comprises at least one intercalated warp and / or weft yarn, arranged predominantly in standby between the front surface and the back surface, and protruding at times at the level of the front and / or back surface when the angle between the front surface, respectively back surface, has an angle of an amplitude greater than a certain threshold with respect to the median plane, in order to compensate for the variations in spacing between the warp and / or weft yarns caused by this angle.

8. A method for manufacturing a fabric according to any one of claims 1 to 7, wherein a loom comprising a plurality of heddles is used, each heddle having an eyelet, among which a first group of heddles, the eyelets of which are passed through by the warp threads of the upper layer, a second group of heddles, the eyelets of which are passed through by the warp threads of the lower layer, and a third group of heddles, the eyelets of which are passed through by the warp threads of the middle layer, said method characterized in that it comprises the following steps repeated cyclically: - opening of the sheaf, during which: . in the first group of heddles, the eyelets of a first subgroup are placed in a high position, above the median plane, and the eyelets of a second subgroup are placed in an intermediate high position, between the median plane and the high position, and / or .In the second group of smooths, the eyelets of a first subgroup are placed in a low position, below the median plane, and the eyelets of a second subgroup are placed in an intermediate low position, between the median plane and the low position, and . In the third group of smooths, each of the eyelets is individually placed in a low position, a high position, an intermediate low position, or an intermediate high position.

9.

10. - insertion of at least one weft thread between the warp threads passing through the eyelets in the upper position and the warp threads passing through the eyelets in the intermediate upper position, and / or of at least one weft thread between the warp threads passing through the eyelets in the lower position and the warp threads passing through the eyelets in the intermediate lower position, - closing of the crowd, during which the eyelets previously placed in the upper position are moved to the upper intermediate position, and / or the eyelets previously placed in the lower position are moved to the lower intermediate position, and in that: - during at least one open-the-sheaf step, for at least one eyelet, the distance between the median plane and that eyelet in the intermediate high or low position is modified, compared to the previous open-the-sheaf step, in order to form a relief on the front or back surface in the warp direction of the fabric, and / or - during at least one open-the-sheaf step, the distance between the median plane and the intermediate high position is different for at least two eyelets in the intermediate high position and / or the distance between the median plane and the intermediate low position is different for at least two eyelets in the intermediate low position, in order to form a relief on the front or back surface respectively in the weft direction of the fabric. A method for manufacturing a fabric according to claim 8, wherein the distance between the median plane and the intermediate low and / or high position varies continuously: - during at least three successive stages of opening the crowd for a single eyelet, in order to form a continuous slope on at least one of the fabric surfaces in the warp direction, and / or - during a single opening step of the swarm, for at least three eyelets crossed by consecutive warp threads in the weft direction, in order to form a continuous slope on at least one of the fabric surfaces in the weft direction. A method for manufacturing a fabric according to any one of claims 8 to 9, wherein, when an eyelet is in an intermediate low or high position, its position is configured so that the warp yarn passing through it, between this eyelet and the fabric's weft, has a correction angle with the median plane enabling compensation of the tension of recall of the binding threads at the level of the weft and to obtain a defined distance between the median plane and the front or back surface of the fabric.

11. A method for manufacturing a fabric according to claim 10, comprising a pre-step of determining the mathematical relationship for linking a distance between the median plane and the front or back surface to a correction angle value, comprising the following steps: - weaving along a plurality of correction angles, until stabilization of the distance between the median plane and the front or back surface, - measuring the distance between the median plane and the front or back surface.

12. A method for manufacturing a fabric according to claim 11, wherein the pre-step of determining the mathematical relationship for linking a distance between the median plane and the front or back surface to a correction angle value is repeated several times, by varying the spacing between two consecutive back-and-forth passes of the binding yarns, in order to obtain a plurality of mathematical relationships for linking a distance between the median plane and the front or back surface to a correction angle value, each mathematical relationship corresponding to a particular spacing between two consecutive back-and-forth passes of the binding yarns.

13. A method of manufacturing a fabric according to any one of claims 11 to 12, wherein the pre-step of determining the mathematical relationship for linking a distance between the median plane and the front or back surface to a correction angle value is repeated several times, varying the weave of the fabric, in order to obtain a plurality of mathematical relationships for linking a distance between the median plane and the front or back surface to a correction angle value, each mathematical relationship corresponding to a particular weave.

14. A method for manufacturing a fabric according to any one of claims 8 to 13, wherein during the closing step of the snag, the eyelets in the upper, or lower, position are moved to the intermediate upper, or intermediate lower, position, respectively. one after the other in the weft direction, ending with the eyelets located on the side where the reserve of said weft yarn is located.

15. A method of manufacturing a fabric according to any one of claims 8 to 14, wherein the movement of each eyelet is controlled by an individual motor.

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