Method for manufacturing a fabric

Abstract

The invention relates to a fabric that comprises: - an upper layer, comprising warp and weft yarns, defining a right side of the fabric; - a lower layer, comprising warp and weft yarns, defining a wrong side of the fabric; - a median plane, situated between the upper layer and the lower layer; and - a central layer, arranged on either side of the median plane, comprising at least warp and / or weft binding yarns. This fabric is characterised in that the binding yarns are configured to maintain a certain distance between the median plane and the right side and / or the wrong side, said distance varying in the warp direction of the fabric and / or in the weft direction of the fabric, so as to form a raised pattern on a surface of the fabric. The present invention also relates to a method for manufacturing a fabric according to the invention.

Description

[0001] DESCRIPTION

[0002] Title: Fabric and associated manufacturing process

[0003] technical field

[0004] 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.

[0005] Previous technique

[0006] Weaving is a manufacturing process used to create fabric from textile threads. During weaving, two sets of threads are interlaced perpendicularly: the warp threads, which run lengthwise in the direction of the weave, and the weft threads, which pass through the warp threads. The way the threads are interlaced is called the weave structure.

[0007] Several techniques exist to create a raised surface on a fabric using weaving techniques.

[0008] One solution involves weaving with several yarns of very different thicknesses (or counts). A succession of fine warp yarns surrounding a few thicker warp yarns creates subtle reliefs on the fabric's surface. This variation in yarn thickness can be achieved in either the warp or weft direction. This method only produces subtle reliefs, and their shapes are limited to linear forms in either the warp or weft. A second method creates textured effects by varying the weave structure in different areas of the fabric. This variation in weave structure is combined with variations in the tension of the warp yarns during weaving, and possibly the weft yarns as well. This method produces gentle undulations on the fabric's surface.This method is not suitable for creating reliefs other than embossed or wavy effects, and the changes on the reverse and front sides of the fabric are generally linked.

[0009] A third method for creating surface texture on a fabric is to lay the threads transversely across the fabric's surface. This is the technique used for velvet weaves. The texture can be linear, to create a corduroy, or other shapes can be generated if the velvet is woven on a Jacquard loom, which allows for 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 the case of warp velvet, 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 fabric's appearance is altered in the textured areas, whether the texture is formed by the pile or the loops.The weaving pattern located beneath the loops or hairs is then invisible.

[0010] Description of the invention

[0011] The present invention aims to overcome these drawbacks by proposing a fabric comprising:

[0012] - a top layer, comprising warp and weft threads, defining the right-side surface of the fabric,

[0013] - a lower layer, comprising warp and weft yarns, defining the reverse side of the fabric, - a median plane, situated between the upper and lower layers, and

[0014] - a central layer, arranged on either side of the median plane, comprising at least some warp and / or weft binding threads.

[0015] This fabric is special in that the binding threads are configured to maintain a certain distance between the median plane and the front and / or 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.

[0016] Thanks to these arrangements, a wide variety of reliefs can be obtained precisely, on one or both sides of the fabric, solely through weaving techniques, the fabric being able to be manufactured with existing looms.

[0017] The binding threads 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 and back surfaces 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.

[0018] The upper and / or lower layer may have at least two levels of superimposed warp yarns and at least two levels of superimposed weft yarns, which allows one level to have the function of giving a certain appearance to the surface of the fabric, and the other level to have a technical function of keeping the binding yarn in its sheath, which allows on one hand to have an appearance with fewer defects, and on the other hand a better mechanical hold of the reliefs generated by the binding yarn on the reverse and / or front surfaces.

[0019] The binding threads can make round trips 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 round trips of the binding threads from the median plane, which is a simple and effective means of implementing the invention.

[0020] 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 allows 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.

[0021] 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 fabric surfaces over time.

[0022] The said fabric may include at least one intercalated warp and / or weft yarn, arranged predominantly in standby between the front and back surfaces, and occasionally protruding at the front and / or back surface when the angle between the front and / or back surfaces 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 with such an angle.The present invention also relates to a method of 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:.

[0023] - opening of the crowd, during which:

[0024] . 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

[0025] 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

[0026] . 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,

[0027] - 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,

[0028] - closing of the swarm, during which the eyelets previously placed in the upper position are moved to the intermediate upper position, and / or the eyelets previously placed in the lower position are moved to the intermediate lower position, and in that: - during at least one swarm opening step, for at least one eyelet, the distance between the median plane and this eyelet in the intermediate upper or lower position is modified, relative to the previous swarm opening step, in order to form a relief on the right or wrong side surface in the warp direction of the fabric, and / or

[0029] - 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.

[0030] Thanks to these arrangements, a wide variety of reliefs can be obtained precisely, on one or both sides of the fabric, solely through weaving techniques, the fabric being able to be manufactured with existing looms.

[0031] The distance between the median plane and the intermediate low and / or high position can vary continuously:

[0032] - 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

[0033] - 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.

[0034] 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 fabric's weft, has a correction angle with the median plane allowing to compensate for the return tension of the binding threads at the weft 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 accurately generate the desired relief on one or both sides of the fabric.

[0035] The said fabric manufacturing process may include a pre-step of determining the mathematical relationship linking a distance between the median plane and the front or back surface to a correction angle value, comprising the following steps:

[0036] - weaving according to a plurality of correction angles, until the distance between the median plane and the front or back surface stabilizes,

[0037] - 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.

[0038] 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.

[0039] 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, varying the fabric weave, 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.

[0040] During the closing stage of the swarm, the eyelets in the upper and lower positions can be moved to the intermediate upper and intermediate lower positions, 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 allows the weft yarns to be given the necessary length to travel over the reliefs of the fabric, and thus avoid overtension problems.

[0041] 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.

[0042] Brief description of the drawings

[0043] 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:

[0044] [Fig 1] Fig. 1 is a schematic view of a fabric according to a particular embodiment of the invention, showing the relief of the front surface relative to its median plane,

[0045] [Fig 2] Fig. 2 is a schematic cross-sectional view along the plane parallel to the Z-axis and the weft direction of the fabric in Figure 1.

[0046] [Fig 3] Fig. 3 is a schematic cross-sectional view along the plane parallel to the Z-axis and the warp direction of the fabric of Figure 1, [Fig 4] Fig. 4 is a schematic cross-sectional view along the plane parallel to the Z-axis and the warp direction of the weave of a fabric according to an exemplary embodiment of the invention,

[0047] [Fig 5] Fig. 5 is a schematic cross-sectional view along the plane parallel to the Z-axis and the weave direction of the weave of Figure 4,

[0048] [Fig 6] Fig. 6 is a schematic cross-sectional view along the plane parallel to the Z-axis and the weave direction of the weave of Figure 4, under different conditions of relief formed by the fabric surfaces,

[0049] [Fig 7] Fig. 7 is a schematic cross-sectional view along the plane parallel to the Z-axis and the weft direction of the weave of Figure 4, under different conditions of relief formed by the fabric surfaces, with the presence of intercalated yarns,

[0050] [Fig 8] Fig. 8 is a schematic cross-sectional view along the plane parallel to the Z-axis and the warp direction of the fabric manufacturing process according to a preferred embodiment of the invention, when the crowd is open,

[0051] [Fig 9] Fig. 9 is a detailed view of one of the elements in Figure 8.

[0052] [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 Figure 8, when the swarm is open,

[0053] [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 Figure 8, when the crowd is being closed.

[0054] Description of the implementation methods

[0055] 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 Figure 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, that is, 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.

[0056] 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.

[0057] 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 attached figures, on which the upper layer 2 is generally shown above the lower layer 3. However, the fabric can of course be turned inside out, and present its right side surface 3 above its wrong side surface 5.

[0058] The top layer 2 and the bottom layer 4 each comprise warp yarns 7 and weft yarns 8, woven together in a weave. The weave may be uniform throughout the top layer 2, or different weaves may be used in different areas of the top layer 2. The weave may be uniform throughout the bottom layer 4, or different weaves may be used in different areas of the bottom layer 4. The weave or weaves used in the top layer 2 may be the same as, or different from, the weave or weaves used in the bottom layer 4.

[0059] Fabric 1 has a median plane 9, located 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 in a way 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".

[0060] 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, some weft and / or warp yarns from the upper layer 2, lower layer 4, or the central layer 6, may interlace with the warp and / or weft yarns of the adjacent layer. Therefore, the central layer 6 does not extend strictly between the upper layer 2 and the lower layer 4. Figures 4 and 5 illustrate, for example, 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. However, in most cases, the central layer 6 extends primarily 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.

[0061] Figures 2 and 3 respectively show the fabric 1 in cross-section, with three layers: an upper layer 2 and a lower layer 4, each corresponding to a distinct depth according to Tax X and Tax Y, respectively. The middle layer 6 contains binding yarns 10, which can be weft or warp yarns. However, it is preferable for the middle layer 6 to contain at least one layer of warp yarns. If at least some of the binding yarns 10 are warp yarns, the middle layer 6 may contain only these binding yarns 10. Conversely, if the binding yarns 10 are exclusively weft yarns, the middle layer 6 preferably also contains warp yarns.

[0062] The binding threads 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 Figure 3, the binding thread 10, which is a warp thread, maintains a distance between the warp threads 7 of the upper layer 2 and the median plane 9, and between the warp threads 7 of the lower layer 4 and the median plane 9.

[0063] Fabric 1 thus exhibits a variable thickness, as illustrated in Figures 1 to 3. The X-axis corresponds to the warp direction, i.e., parallel to the warp threads 7, and the Y-axis corresponds to the weft direction, i.e., parallel to the weft threads 8. The thickness of fabric 1, and the surface textures it presents, therefore 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. Fabric 1 thus has at least one texture on at least one of its two surfaces 3 and 5, in order to obtain a topography that offers, for example, a certain aesthetic appeal. The reliefs present on the front surface 3 and on the back surface 5 can coincide with each other, for example with a symmetry with respect to the median plane 9, or in such a way that the surfaces 3, 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 a great freedom in the design of the fabric 1.

[0064] 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 back surface 5 which are not symmetrical to each other.

[0065] In the example shown in Figure 3, we observe that the space defined by the back-and-forth movements of the binding thread 10 between the upper layer 2 and the lower layer 4 can vary along the X-axis, allowing for relief patterns along the direction of the binding thread 10, that is, in this figure, along the warp direction. In this example, relief patterns along the weft direction can be produced because each back-and-forth movement of a warp binding thread 10 can have a different shape.

[0066] 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 surfaces 3, 5 are derived.

[0067] 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.

[0068] Whether the binding yarns 10 are warp yarns, weft yarns, or whether the fabric contains 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 in 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.

[0069] As illustrated in Figures 4 to 7, the upper layer 2 and / or the lower layer 4 is preferably multilayered, meaning 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 yarns 7 and weft yarns 8 are then preferably superimposed sympathetically, that is, without crossing along the Z-axis. Figures 4 and 5 illustrate, for example, a fabric 1 having two layers of warp yarns 7 and two layers of warp yarns 8 in each of its lower layer 2 and upper layer 4. Multilayered compositions allow the use of different yarns 7 and 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 usually, or even always, remain 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 for a very clean front 3 and / or back 5 surface, free from surface defects due to differences in stiffness between the binding yarns 10 and the other yarns 7, 8 of the fabric 1. As illustrated in Figure 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 to the central layer 6.

[0070] In this embodiment, the back-and-forth movements of 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, or back surface 5, to be varied. More precisely, the variation in length at the portion of these back-and-forth movements located between the median plane 9 and the upper layer 2, or lower layer 4, and the front surface 3, or back surface 5, allows the distance between the median plane 9 and the front surface 3, or back surface 5, to be varied. This therefore makes it possible to generate the reliefs on the front surface 3 and back surface 5 independently.

[0071] 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 varying crush resistance in different areas of the fabric, providing a changing tactile experience. Conversely, in other embodiments, or in other areas of the fabric 1, this variation compensates for variations in the length of the back-and-forth movements of the warp yarns 10 in order to maintain constant crush resistance across the entire fabric 1 or a specific 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.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.

[0072] 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 Figure 5, the dashed lines represent the binding yarns 10 connecting the upper layer 2 and lower layer 4. In the example shown, Figure 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.

[0073] As shown in the example in Figure 5, it is preferable for the weft threads 8 on the surface to move progressively, that is, by going up and down one warp thread 7 after the other, without plunging under two, for example. This allows for a better aesthetic appearance of the fabric 1.

[0074] 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 one can use a single yarn 7, 8 of a certain color, which remains hidden over almost the entire fabric 1, and emerges on surface 3, 5 at specific points. 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, 5. On the weave shown near the origin of the coordinate system in Figure 6, the curves followed by the surfaces 3, 5 of fabric 1 have relatively small angles with the Z-axis.For this type of relief, where the angles for example are less than or equal to a threshold between 25 and 40°, for example 30°, we can expect that the appearance of fabric 1 on the surface is only slightly, if at all, impacted by the relief.

[0075] On the weave shown at a distance from the origin of the coordinate system, the curves followed by surfaces 3 and 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 specifically, in Figure 6, it can be seen that some weft yarns 8 and warp yarns 7, which are normally hidden under the surface weft yarns 8 and warp yarns 7, 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 because the warp threads 7 are positioned at specific locations in the weft direction (on the x-axis of the coordinate system in Figure 6), and can only move very slightly in this direction. Various methods can be used to address this issue.

[0076] One method is to design fabric 1 with a high saturation ratio, for example, greater than 1.3, for the weft yarns 7 and 8 located on the right side surface 3 and / or the wrong side 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 if the surface yarns are spread apart due to a large angle between the surface 3, 5 and the median plane 9, as seen in Figure 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 spacings between the surface yarns 7, 8 that are not too large, therefore for reliefs that do not have excessively large angles relative to the median plane 9.

[0077] A second method, which can be combined with the first, is to use a surface weave with floats, preferably at least three, in the weft. Such weft threads 8 remain above or below several consecutive warp threads 7, allowing changes in weft thread spacing 8 to be masked.

[0078] In a third method, an example of which is shown in Figure 7, fabric 1 has intercalated yarns 12a, 12b. These intercalated yarns, shown as warp in Figure 7 but which can also be arranged as weft, are mostly positioned invisibly within fabric 1, as in Figure 7 with the intercalated yarn in position 12a. When they need to be used, the weave changes locally to allow the intercalated yarns in position 12b to be brought up to the surface 3, 5 of fabric 1. The references 12a, 12b therefore designate the same intercalated yarns, which are in position 12a in some places of fabric 1, and in position 12b in others. This rise is illustrated by a dotted arrow in figure 7. The intercalated wires 12a, 12b, when they are waiting, can be in the central layer 6, or in one of the upper 2 or lower 4 layers.

[0079] The warp 7 and weft 8 yarns may all be identical, or they 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. When the lower layer 2 or upper layer 4 has several layers of superimposed yarns 7, 8, the yarns 7, 8 protruding on the right side 3 and / or wrong side 5 surface preferably have a count, expressed in Tex, greater than or equal to the count of the yarns 7, 8 below the surface. This helps to reduce the risk of over-saturation of the internal level of 7, 8 wires compared to the surface 7, 8 wires, which could lead to appearance defects.

[0080] The binding yarns 10, for their part, are preferably composed of monofilament yarns, allowing for good rigidity. These monofilaments should have a diameter no greater than the other yarns 7, 8, or even preferably smaller than the other yarns 7, 8 of fabric 1, in order to reduce the risk of over-saturation of the central layer, and therefore of surface defects 3, 5 of fabric 1, these risks being all the more significant as the binding yarns 10, being mostly more rigid, compress little.

[0081] Fabric 1 can be manufactured using a loom as shown in Figure 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 arranged at certain times during the weaving process in position 13a, and at other times in position 13b, 13c or 13d, as described below. The eyelets 13a, 13b, 13c, 13d are crossed by the warp threads of fabric 1, and are mobile in translation along the Z axis, that is to say 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.

[0082] 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.

[0083] The manufacturing process then involves successive stages of opening the swarm, inserting at least one weft yarn into the swarm, and then closing the swarm.

[0084] 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 eyelets 13, change position by following a translational movement perpendicular to the median plane during the opening and closing stages of the crowd.

[0085] 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 steps 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. Thus, the sheaf-opening step includes at least one of the following substeps, and in some cases both of the following substeps:

[0086] - 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,

[0087] - some 13c eyelets of the second group are placed in a low position while other 13d eyelets of the second group are placed in an intermediate low position.

[0088] During the sheaf opening stage, each eyelet 13a, 13b, 13c, 13d of the third group can be placed in one of the following positions, independently of each other, depending on the chosen weave: high position, low position, high intermediate position, and low intermediate position. If this stage coincides with an interlacing of a weft yarn 8 from the top layer 2, or bottom layer 4, with a warp yarn from 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 the high position, or low position, respectively. It should be noted that in the case where the binding yarns 10 are in the weft, it can be assumed that the warp yarns of the middle 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.

[0089] 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 and 16b are delimited in the weft direction on one side by the weft 15 of the fabric 1 and on the other side by the plane in which the eyelets 13 are located.

[0090] The next step consists of inserting at least one weft thread 8 into one or both of these spaces. The number of weft threads 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 threads 8 can be done by shuttle 17, or by spear, or by any other insertion method.

[0091] Once the weft threads 8 are inserted, the sheaf is then closed, i.e. the eyelets 13a which were placed in the high position are brought back to the intermediate high position, and the eyelets 13c which were placed in the low position are brought back to the intermediate low position.

[0092] The process described above can be used to weave a fabric 1 with 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. To do this, the superimposed warp yarns, 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 yarn 8 closest to the median plane 9 is inserted first, and then, during the subsequent opening of the sheaf, the weft 15 of the fabric 1 is not shifted in the warp direction.

[0093] In the above process, steps corresponding to a three-part sheaf opening were 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 enables the simultaneous insertion of 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

[0094] 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 creation of the envelope 11 occupied by the binding thread 10, from which the relief is derived. Depending on the desired type of relief, 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, state-of-the-art fabric, without relief, would be obtained.

[0095] In the 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 low or high intermediate position of an eyelet can vary over time and differ according to distinct stages of the weave opening. This concerns at least one eyelet, but preferably a plurality of eyelets. This variation may occur only between two consecutive stages of the weave opening, but it preferably occurs between several pairs of consecutive stages of the weave opening. If the low intermediate position is involved, then the relief is generated on the reverse side surface 5, and if the high intermediate position is involved, the relief is generated on the front side surface 3.

[0096] 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 the swath opening. This variation involves at least one eyelet 13, and preferably a plurality of eyelets 13. This allows for the formation of a continuous slope on one of the surfaces 3, 5 of the fabric in the warp direction. To implement this first mode, a loom is preferably used that allows for the precise positioning of the height of the eyelets 13a, 13b, 13c, 13d 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.

[0097] In a second mode, the variation of intermediate positions occurs along the weft direction of fabric 1, generating a raised pattern in the weft direction of fabric 1. To achieve this, the lower or upper intermediate position of several eyelets differs during a single opening step of the swarm, as illustrated in Figure 11. This variation preferably takes place during several opening steps of the swarm, and in particular several consecutive steps, to create raised patterns on the right side 3 and / or wrong side 5 surface extending in both the warp and weft directions. If the lower intermediate position is involved, then the raised pattern is generated on the wrong side 5 surface, and if the upper intermediate position is involved, the raised pattern is generated on the right side 3 surface.

[0098] It should be noted that what is referred to in this description as the position of an eyelet 13 corresponds to the area of ​​eyelets 13a, 13b, 13c, 13d through which the warp thread passes. As shown in Figure 8, this position corresponds to the lower end of eyelets 13a, 13b, 13c, 13d for the high and upper intermediate positions, and the upper end of eyelets 13a, 13b, 13c, 13d for the low and lower intermediate positions.

[0099] 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 threads, that is, threads belonging to the same warp thread level. These warp threads can be binding threads 10, or warp threads 7 belonging to the lower layer 2 or upper layer 4, or warp threads belonging to the middle layer 6 that are not binding threads. This variation involves at least one sheaf opening step, and preferably several sheaf opening steps. This allows for the formation of a continuous slope on one of the fabric surfaces 3, 5 in the weft direction.

[0100] To implement this first method, 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

[0101] The two modes described above can be combined to obtain reliefs taking complex forms in the warp and weft direction of fabric 1.

[0102] 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, although these examples are not exhaustive.

[0103] In the process according to the invention, the intermediate low and high positions are determined based on 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.

[0104] In a first approach, when we want 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, we can arrange the eyelets 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, we want the envelope 11 defined by the binding thread 10 to rise up to 2.5 mm above the median plane 9 and up to 1 mm below the median plane, we can place the eyelets 13b 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.

[0105] In a second approach, the lower and upper intermediate positions are further from the median plane 9 than the desired distance between the ends of the binding wire's sheath 11 and the median plane 9. This additional distance E, shown in Figure 10, particularly with the guide curve 18 on which the eyelets 12b, 12d are placed, allows for consideration of the restoring tension of the binding wires 10 at the splay 15, and thus for more precise control of the reliefs generated on surfaces 3, 5. The additional distance 18 corresponds to the distance, along the Z-axis, between the upper or lower end of the sheath 11 occupied by the binding wire 10 and the eyelet 13b, 13d, and is determined independently for the lower and upper intermediate positions, and independently for each eyelet 13b, 13d that occupies one of these positions, as a function of the envelope 11 that we want to give to the binding thread 10.For each eyelet 13b, 13d, the additional spacing 18 corresponds to a correction angle α between the median plane 9 and the warp thread passing through the eyelet 13b, 13d, considering the portion of this warp thread 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 thread 10 must be compensated. This restoring tension depends on several parameters, notably the flexural stiffness of the binding threads 10, and the weaves chosen for the binding thread 10 and for the bonding of the binding thread 10 with the lower 2 and upper 4 layers.

[0106] The determination of the correction angle α can be carried out during a preliminary 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 wrong side surface 5. This preliminary step can be performed empirically, by conducting 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 surface height.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 back surface 5.

[0107] It should be noted that the relationship between the correction angle α 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 passes of the binding yarns 10, etc. All of these factors, taken together, constitute at any given moment what can be called a weaving scenario. To weave with maximum precision, before proceeding with the weaving, the pre-step described above is repeated as many times as there are scenarios to be used to weave the fabric 1. To save time, one can choose to group together certain scenarios that are sufficiently similar, particularly because they have a number of identical or similar factors, and perform only one pre-step per group of scenarios.

[0108] Once the angle of correction 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.

[0109] 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 reliefs of fabric 1, and the risk of overtension problems is reduced.

[0110] 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 heap is closed first, as illustrated in Figure 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 heap will close progressively, starting with the eyelets 13a, 13c located closest to the exit position of the spear head of the heap. The present invention is, of course, not limited to the embodiments described but extends to any modification and variation obvious to a person skilled in the art, within the limits of the appended claims. Furthermore, the technical features of the various embodiments and variations mentioned above may be combined, in whole or in part.

Claims

Demands

1. A method for manufacturing a fabric, said 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, positioned between the upper and lower layers, and - a central layer, arranged on either side of the median plane, comprising at least some binding warp and / or weft yarns, the binding yarns being configured to maintain a certain distance between the median plane and the front and / or 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, a process in which a loom is used having a plurality of heddles, each heddle having an eyelet, among which a first group of heddles, the eyelets of which are passed through by the warp yarns of the upper layer, a second group of heddles, the eyelets of which are passed through by the warp yarns of the lower layer, and a third group of heddles, the eyelets of which are passed through by the warp yarns of the central layer,said process 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 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-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.

2. A method for manufacturing a 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 to form reliefs on the front surface and on the back surface not symmetrical with respect to the median plane.

3. A method of manufacturing a fabric according to any one of claims 1 or 2, characterized in that the upper layer and / or the lower layer comprises at least two superimposed warp yarns and at least two superimposed weft yarns.

4. A method of manufacturing a fabric according to any one of claims 1 to 3, characterized in that the binding yarns make back-and-forth movements between the upper layer and the lower layer, 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. A method of manufacturing a fabric according to claim 4, characterized in that the space between two consecutive back-and-forth movements made by the binding warps between the upper layer and the lower layer varies in the warp direction of the fabric and / or in the weft direction of the fabric.

6. A method of manufacturing a 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. A method for manufacturing a 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 a waiting position between the front surface and the back surface, and protruding at specific points at the level of the front and / or back surface when the angle between the front surface, respectively the back surface, has an angle of greater amplitude than a certain threshold with respect to the median plane, in order to compensate for variations in spacing between warp and / or weft threads caused by this angle.

8. A method for manufacturing a fabric according to any one of claims 1 to 7, 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.

9. A method of manufacturing a fabric according to any one of claims 1 to 8, 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 weft of the fabric, has a correction angle with the median plane enabling the return tension of the binding yarns at the weft to be compensated for and a defined distance to be obtained between the median plane and the front or back surface of the fabric.

10. A method for manufacturing a fabric according to claim 9, comprising a pre-step for 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.

11. A method for manufacturing a fabric according to claim 10, 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 movements 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 movements of the binding yarns.

12. A method for manufacturing a fabric according to any one of claims 10 to 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, 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.

13. A method of manufacturing a fabric according to any one of claims 1 to 12, wherein during the closing of the sheaf step, the eyelets in the upper position, respectively lower, are 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.

14. A method of manufacturing a fabric according to any one of claims 1 to 13, wherein the movement of each eyelet is controlled by an individual motor.

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