Three-dimensional weaving method with yarn exit

Abstract

The invention relates to a method for weaving a texture (200) between warp yarns (210) and weft yarns (220) by means of a weaving loom (100) comprising at least one lance (130) which is able to pass through the loom (100) along a reference path (T130) and to draw a weft yarn (220), the method comprises at least displacing at least part of the warp yarns intended to exit from the texture (200) so that the yarns are arranged on one side of the reference path (T130) and the rest of the non-exiting warp yarns are arranged on another side of the reference path (T130), followed by the lance (130) passing through the loom (100) along the reference path (T130) without drawing any weft yarn.

Description

Description Title of the invention: Three-dimensional weaving method with yarn outlet Technical Field

[0001] The present invention relates to the three-dimensional weaving of woven textures using a Jacquard type loom, and in particular to textures having thickness variations requiring yarn outlets. Prior art

[0002] A Jacquard type loom is conventionally used for producing textures by three-dimensional weaving between a plurality of layers of warp threads and a plurality of layers of weft threads. Such a loom is described in particular in document FR 3 074 195 A1, in the name of the applicant.

[0003] As is known, the loom is equipped with a Jacquard mechanism. The loom also includes a harness comprising control or heddle threads, each control thread being connected at one end to a control element of the Jacquard mechanism.

[0004] Each control thread comprises an eyelet through which a warp thread passes. The control threads and their associated eyelet are capable of moving vertically. The control threads allow certain warp threads to be lifted and thus create a shed, i.e. an opening between lower and upper layers of warp threads. Said shed thus opened allows the introduction of a weft thread by means of a lance, said lance having a fixed vertical position. The lance comprises a rod which can be provided at its end with a clamp which grips a weft thread from a bobbin to place it through the opening between the layers of warp threads created by the shed, the weft thread being cut using a cutting tool after its positioning in the shed.

[0005] When we want to make thick woven textures with a variation in thickness, it may be necessary to bring out threads at the point of the decrease in thickness so that they are not woven. In order to maintain a satisfactory and continuous surface condition of the woven texture, we generally seek to bring out threads present in underlying layers of warp threads, which are therefore not present on the surface. Thus, by actuating the control threads, the warp threads are moved in the harness so that the warp threads to be brought out pass through the surface layer of warp threads and are placed out of the path of the rapier. The other threads are then weaved in the classic way, from the upper surface layer of warp threads to the lower surface layer of warp threads.

[0006] However, the crossing of the warp yarns to be taken out with the surface warp yarns can generate friction and tensions, particularly when the warp yarns to be taken out must pass through many layers of warp yarns. The associated control yarn eyelets can thus be poorly positioned in the harness and significant tensions can be generated in the control yarns. In particular, a phenomenon of control yarn advance can be observed, which results in a vertical misalignment of the control yarns which engage in the reed of the loom. The friction and stresses applied to the control yarns can then cause regular interruptions in the weaving, or even a prolonged stoppage of the weaving. In addition, if the warp yarns are poorly positioned in the harness, warp yarns to be taken out can become blocked at the level of the layers of surface warp yarns, and thus be woven by mistake. Statement of the invention

[0007] The present invention aims to remedy the aforementioned drawbacks by proposing a weaving method allowing the production of woven textures by three-dimensional weaving comprising thread exits through layers of warp threads.

[0008] To this end, the invention proposes a method for three-dimensional weaving of a texture between a plurality of layers of warp threads superimposed in a vertical direction and a plurality of weft threads extending in a horizontal direction, the weaving being carried out by means of a loom comprising a plurality of control threads, a first end of each control thread being connected to a Jacquard mechanism capable of moving the control threads according to the vertical direction between a neutral position and at least one opening position of the warp threads, each control thread being further provided with an eyelet crossed by a warp thread, the loom further comprising at least one lance present downstream of the control threads capable of crossing the loom according to a 5 fixed horizontal reference path and to draw a weft thread from a bobbin,

[0009] characterized in that the method further comprises at least one step of outputting warp threads comprising:

[0010] - moving in the vertical direction all or part of the warp threads of at least one layer of underlying warp threads of the plurality of layers of warp threads, said moved warp threads being intended to be taken out of the texture, over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads, so that the moved warp thread(s) are arranged above the reference path and the remainder of the unmoved warp threads are arranged below the reference path, or so that the moved warp thread(s) are arranged below the reference path and the remainder of the unmoved warp threads are arranged above the reference path, then

[0011] - the crossing of the loom by the lance according to the reference path without pulling any weft thread. O

[0012] By performing an empty rapier stroke, it is ensured that the warp threads to be taken out are correctly separated from the layers of warp threads to be woven, even when the warp threads to be taken out must cross many layers of surface warp threads or even when a significant number of warp threads have been moved in the harness. It is therefore ensured that the warp threads to be taken out are correctly positioned in relation to the warp threads to be woven. This facilitates the movement of the control threads and the associated eyelets in the harness, which are arranged in the correct position without generating tension or friction. This greatly limits the stress on the control threads, which allows for smoother weaving with few interruptions. Weaving errors generated by poor placement of the control threads in the harness are also reduced. The weaving speed can therefore be increased, while improving the quality of the weaving obtained.

[0013] According to a particular embodiment of the invention, when weaving at least one weft column, a plurality of layers of underlying warp threads is intended to be taken out of the texture beyond one of the layers of warp threads present on the surface of the plurality of layers of warp threads, the following step of taking out warp threads being repeated for each layer of warp threads to be taken out beyond said layer present on the surface:

[0014] moving the warp yarn layer to be taken out in the vertical direction over a determined distance extending beyond the warp yarn layer present on the surface of the plurality of warp yarn layers, such that the moved warp yarn layer is arranged above the reference path and below the previously moved warp yarn layers intended to be taken out of the texture and the remainder of the untaken warp yarns are arranged below the reference path, or such that the moved warp yarn layer is arranged below the reference path and above the previously moved warp yarn layers intended to be taken out of the texture and the remainder of the untaken warp yarns are arranged above the reference path; then passing the rapier through the loom along the reference path without pulling any weft yarn.

[0015] By carrying out the exits of the layers of warp threads one after the other, with a free lance stroke for each layer of warp thread moved, the number of simultaneous crossings with the surface layer of warp threads is limited. The exit of the layers of warp threads is therefore facilitated and is carried out by generating very little stress at the harness level.

[0016] According to another particular embodiment of the invention, the step of exiting warp threads further comprises, after the lance has passed through the weaving loom without pulling any weft thread:

[0017] - the movement in the vertical direction of a part of the displaced warp threads or of a part of the displaced layer so that said part of the displaced warp threads or of the displaced layer is arranged below the reference path and the other part of the displaced warp threads or of the displaced layer of yarn is arranged above the reference path, then

[0018] - the crossing of the loom by the lance along the reference path by pulling a weft thread so as to link the displaced warp threads together.

[0019] Thus, after having taken out the warp threads using vacuum lance strokes, the taken out warp threads can be linked together to reduce the risks of some taken out warp threads being mistakenly woven with the texture, and to facilitate the subsequent cutting of the taken out warp threads.

[0020] Preferably, the drawn warp threads are bound with a two-dimensional weave.

[0021] According to another particular embodiment of the invention, the loom further comprises a guide device present downstream of the plurality of control threads and the rapier, the guide device being able to move in the vertical direction so as to move the woven texture upwards or downwards relative to a horizontal reference plane comprising the reference path.

[0022] Since the reference path of the rapier is fixed vertically, such a guide device capable of vertically moving the texture makes it easier to make rapier strokes, empty or with a weft thread, in the highest and lowest layers of warp threads. In addition, such a guide device makes it possible to move the texture as each weft column is woven to position it in the best position to facilitate the uncrossing of the warp threads and improve the positioning of the texture in relation to the shed opening used.

[0023] The guide device may further comprise an upper guide bar and a lower guide bar configured to be positioned in contact with the woven texture and on either side of said texture in the vertical direction, the minimum value of the spacing between the guide bars corresponding to the thickness of the uncompacted woven texture.

[0024] Furthermore, the woven texture according to the invention may be abundant and require subsequent compaction. Thus, it is preferable to have sufficient spacing between the guide bars so as not to deform the texture. Furthermore, the correct production of warp thread outlets may require very small shed openings. However, too narrow a spacing of the guide bars can prevent the implementation of large crowd openings.

[0025] According to another particular embodiment of the invention, the spacing between the guide bars increases during the movement in the vertical direction of all or part of the warp threads intended to be taken out of the texture over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads.

[0026] Indeed, the creation of warp thread outlets requires large height amplitudes of the eyelets in the harness, as well as very wide shed openings. By increasing the spacing between the guide bars at the intersection between the threads to be removed and the surface threads, the possible shed opening is greatly increased and the risk of generating tensions on the harness eyelets is reduced.

[0027] According to another particular embodiment of the invention, the guide bars of the guide device are configured to move in the vertical direction as a function of the vertical position of the eyelets of the harness during the movement in the vertical direction of all or part of the warp threads intended to be taken out of the texture over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads, so that in each plane of the loom perpendicular to the reference path, the length between the harness and the woven texture of the lowest warp thread located above the reference path corresponds to between 90% and 110% of the length between the harness and the woven texture of the highest warp thread located below the reference path.

[0028] Thus, the movement of the guide bars of the guide device is a function of the positions of the eyelets in the harness. By ensuring that the lengths of the crossing wires are similar, we avoid generating significant tensions in certain wires which could pull on the eyelets and generate stresses in the harness.

[0029] According to another particular embodiment of the invention, the guide device is configured to move between a first position and a second position in the vertical direction depending on the vertical position of the eyelets of the harness after the movement in the vertical direction of all or part of the warp threads intended to be taken out of the texture over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads, so that in each plane of the weaving loom perpendicular to the reference path,the length between the harness and the woven texture of the highest warp yarn located below the reference path when the guide device is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp yarn when it is the lowest located above the reference path when the guide device is in the second position.,

[0030] Thus, the warp threads swinging from the lower edge of the shed to the upper edge of the shed after a lance stroke are not subjected to excessive tension, thus facilitating thread crossings.

[0031] According to another particular embodiment of the invention, the warp and weft threads are carbon, glass or ceramic fibers.

[0032] According to another particular embodiment of the invention, the woven texture is intended to form a fibrous reinforcement for a composite material part of an aeronautical engine.

[0033] Indeed, the manufacture of many composite material parts for aeronautics involves producing a three-dimensional weave of significant thickness requiring wire exits to achieve thickness variations. Brief description of the drawings

[0034] [Fig. 1] Figure 1 is a schematic perspective view of a Jacquard type loom in neutral position.

[0035] [Fig. 2] Figure 2 is a schematic perspective view of the loom of the washed figure a crowd creation.

[0036] [Fig. 3] Figure 3 is a schematic sectional view of a woven texture produced by the method of the invention.

[0037] [Fig. 4] Figure 4 is a schematic sectional view of the loom of Figures 1 and 2 as a first layer of warp yarns is taken out through the 5 layer of upper warp threads of a first weft column.

[0038] [Fig. 5] Figure 5 is a schematic sectional view of the loom of Figures 1 and 2 as a second layer of warp yarns is taken out through the upper layer of warp yarns of the first weft column.

[0039] [Fig. 6] Figure 6 is a schematic sectional view of the loom of Figures 1 and 2 during weaving of the upper layer of warp yarns of the first weft column.

[0040] [Fig. 7] Figure 7 is a schematic sectional view of the loom of Figures 1 and 2 during the weaving of a layer of warp yarns underlying the first weft column. i5

[0041] [Fig. 8] Figure 8 is a schematic sectional view of the loom of Figures 1 and 2 at the end of weaving all the underlying layers of warp yarns to be woven from the first weft column.

[0042] [Fig. 9] Figure 9 is a schematic sectional view of the loom of Figures 1 and 2 during weaving of the lower warp yarn layer of the first 20 weft column.

[0043] [Fig. 10] Figure 10 is a schematic sectional view of the loom of Figures 1 and 2 as a fifth layer of warp yarns is taken out through the upper layer of warp yarns of a second weft column.

[0044] [Fig. 11] Figure 11 is a schematic sectional view of the loom of Figures 1 and 2 at the end of weaving all layers of warp yarns of the second weft column.

[0045] Description of the embodiments

[0046] The invention applies generally to three-dimensional weaving methods for producing textures woven between layers of yarns. warp and layers of weft threads. By "three-dimensional weaving" is meant here a weaving method by which at least some of the warp threads bind weft threads over several weft layers. It is considered that a woven texture made by three-dimensional weaving may include another type of weave on its surface, 5 for example two-dimensional weaving, in order to improve its surface condition.

[0047] The woven texture may, for example, have a three-dimensional weave of the interlock or multi-satin type. Different three-dimensional weaving methods that can be used to form the woven texture are described in document WO 2006 / 136755. io

[0048] Figures 1 and 2 illustrate a loom 100 for carrying out the weaving method of the invention. The loom 100 according to the invention makes it possible to obtain a woven texture 200 extending lengthwise in a horizontal direction D. H and in thickness following a vertical direction D v by weaving a plurality of layers of warp yarns 210 with a plurality of layers of weft yarns 220.

[0049] The loom is equipped with a Jacquard mechanism 110 supported by a superstructure not shown in Figures 1 and 2. The loom 100 also comprises a harness 120 comprising control or heddle threads 121, each control thread 121 being connected at one end to a control element 111 of 20 the Jacquard mechanism 110. In the example illustrated in Figures 1 and 2, each control thread 121 is connected at one end to a control hook 111 of the Jacquard mechanism 110 and at the other end to a return spring 112 fixed to the frame 113 of the loom 100. The control threads 121 extend in the vertical direction D v The 120 harness can also include a board 25 of 122 stuffing.

[0050] Each control thread 121 comprises an eyelet 121a through which a warp thread 210 passes. Each warp thread 210 of the loom 100 passes through an eyelet 121a of the harness 120. The warp threads 210 are organized at the harness 120 of the loom 100 into a plurality of horizontal layers and vertical columns 30 which are manipulated by the loom 100 to allow the insertion of weft threads 220 according to the weaving pattern(s) programmed in the loom 100. The weft threads 220 are inserted between the warp threads 210 by column extending in the vertical direction D v . In order to allow the introduction of each column of weft threads 220 during the weaving of the texture 200, a warp thread take-up system 210 (not shown in Figures 1 and 2) is associated with the loom 100. This system, placed downstream of the loom 100, has the role of holding all the warp threads 210 together in a clamping device and of allowing the warp threads 210 to advance by a determined distance in the horizontal direction D. H after inserting each frame column 220.

[0051] The terms “upstream” and “downstream” are defined here according to the direction of advance of the warp threads 210 in the loom 100, that is to say according to the weaving direction, along the horizontal direction D H .

[0052] The control wires 121 and their associated eyelet 121a are able to move in the vertical direction D v . In Figure 1, all the control yarns 121 are in a neutral position in which no traction is exerted by the Jacquard mechanics 110. In this configuration, no shed is created and all the warp yarns 210 extend parallel to the horizontal direction D H .

[0053] When creating a shed, as illustrated in Figure 2, a portion of the control threads 121 are subjected to tensile forces exerted by the control hooks 111. In this configuration, the control threads make it possible to raise or lower warp threads, so as to separate an upper layer 2101 of warp threads from a lower layer 2102 of warp threads by an opening F, called a shed. Several different sheds can be produced by modifying the warp threads raised or lowered using the control threads 121.

[0054] The loom 100 also comprises a lance 130, present downstream of the control threads 121. The lance 130 is composed of a rod 131, a first end of which is connected to an actuation system (not shown in FIGS. 1 and 2) making it possible to drive the rod 131 in a back-and-forth movement along a horizontal reference path TI. 30 , said reference path TI 30being fixed relative to the frame 113 of the loom 100. The reference path TI 30 belongs to a horizontal reference plane PH extending in the horizontal direction D H . The other end of the rod 131 is provided with a clamp 132 which, after passing through the crowd during the outward journey of the rod 131, can come to grip a weft thread 220 stored on a reel 140 to unwind it in the crowd during the return journey of the rod 131. The weft thread 220 thus placed inside the crowd is then cut in the vicinity of the reel 140 by a cutting tool 150 and released at its other end by the clamp 132. A comb 160 present upstream of the lance 130 and downstream of the harness 120 in its rest position is then folded down in order to pack the weft thread(s) 220 introduced into the crowd. In accordance with the invention, the rod 131 can also make the outward and return journey without the clamp 132 coming to grip a weft thread 220: an empty lance stroke is then made. The lance 130 is then ready to pick up a new weft yarn 220 from the bobbin 140 and place it either in the same shed or in a different shed depending on the defined weave.The woven texture 200 is thus gradually formed, presenting a three-dimensional weave between the warp threads 210 and the weft threads 220.

[0055] Preferably, the loom 100 further comprises a guide device 170 for guiding the woven texture 200 present downstream of the control threads 121 and the rapier 130. Such a guide device 170 is described in particular in the document FR 3 074 195 A1. More generally, guide means are known from the document EP 0 573 132 A1. In the example described here, the guide device 170 may comprise a lower guide bar 171 and an upper guide bar 172 each connected to an actuating means (not shown in FIGS. 1 and 2) which is capable on the one hand of holding the woven texture 200 and on the other hand of moving the guide bars 171 and 172 in the vertical direction D. vThe guiding device 170 makes it possible to move the woven texture in the vertical direction D. v upwards or downwards relative to the horizontal reference plane P H including the horizontal reference path Ti 30 of the lance 130. It is thus easier to create crowds at the level of the lower or upper layers of warp threads 210, even with a large number of layers of warp threads 210 superimposed in the vertical direction D v .

[0056] As illustrated in the figures, the guiding device 170 can move the entire woven texture along the vertical direction D v . According to another example not shown, a selvedge area arranged on each edge of the woven texture can be moved following the vertical direction D vindependently of the rest of the woven texture, by a guiding device specific to this area. In other words, the guiding device can be independent of the selvedge areas, each selvedge area being able to have a guiding device specific to this area, so as to move the selvedge area in the vertical direction D v .

[0057] The weaving method according to the invention makes it possible to produce a woven texture 200 comprising at least a first portion 201 and a second portion 203. An example of a woven texture 200 produced by the method of the invention is illustrated schematically in Figure 3. For reasons of clarity and simplification of the diagrams, the texture represented in the example illustrated in Figures 3 to 11 comprises a small number of warp threads and weft threads, and the weave of the said texture is not shown.

[0058] The first portion 201 of the texture 200 is produced by three-dimensional weaving between a first number of warp threads 210 and a first number of weft threads 220. The second portion 203 of the texture 200 is produced by three-dimensional weaving between a second number of warp threads 210, less than the first number of warp threads 210, and a second number of weft threads 220. The second number of weft threads 220 is preferably less than the first number of weft threads 220. Thus, the texture 200 may have a variation in thickness, the second portion 203 possibly being less thick than the first portion 201.

[0059] The texture 200 also comprises a transition portion 202 between the first portion 201 and the second portion 203, in which the number of woven warp threads 210 decreases from the first portion 201 to the second portion 203. The transition portion 202 connects the first portion 201 to the second portion 203 in the weaving direction. The transition portion 202 may correspond to a single weft column or to several weft columns N and N+1 of the texture 200.

[0060] The weaving method according to the invention comprises a first step, in which the three-dimensional weaving of the first portion 201 of the texture 200, which is preferably a portion of high thickness, is carried out. The first portion 201 of the texture 200 is produced in a well-known manner by three-dimensional weaving. between the first number of warp threads 210 and the first number of weft threads 220 by means of the loom 100 previously described.

[0061] When the weaving of the first portion 201 of the texture 200 is completed, the second step of the weaving method according to the invention begins, in which the transition portion 202 of the texture 200 is produced. During this second step, a certain number of warp threads are therefore removed from the weaving to reduce the first number of warp threads and obtain the second number of warp threads.

[0062] In order to obtain a woven texture 200 with a satisfactory and continuous surface condition between the first portion 201 and the second portion 203, it is desired to remove from the weave warp threads belonging to underlying warp thread layers, i.e. not belonging to the upper warp thread layer 210h or to the lower warp thread layer 210b. Preferably, it is desired to remove warp threads not belonging to the upper warp thread layers or to the lower warp thread layers. Therefore, each warp thread or each layer of warp threads that it is desired to remove from the weave must pass through one or more upper or lower surface warp thread layers in the vertical direction D. v .

[0063] For each weft column of the transition portion 202 to be produced, if it is desired to remove warp threads from the weaving through the upper surface warp thread layer 210h in the vertical direction D v , we carry out the sub-steps described below.

[0064] In a first sub-step, the warp threads to be removed, or the entire layer(s) of warp threads to be removed, are placed above the reference path TI. 30 of the lance 130 relative to the vertical direction D v , and the rest of the warp threads are placed below the reference path TI 30 of the lance 130 relative to the vertical direction D v . A crowd is thus created separating on the one hand the warp threads to be removed, or the entire layer(s) of warp threads to be removed, from the rest of the warp threads, said crowd comprising the reference path TI 30This configuration is obtained by actuating the control wires 121 of the harness 120, so as to arrange the eyelets 121a crossed by warp wires to be removed above the eyelets 121a crossed by the rest of the warp wires 210.

[0065] The terms "above" and "below" must be understood in the vertical direction D v , and preferably relative to the direction of gravity.

[0066] Preferably, this configuration is also obtained by arranging the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 in a vertical position allowing the warp threads to be removed, or the entire layer(s) of warp threads to be removed, to be arranged above the reference path TI 30 of the lance 130, and so as to arrange the rest of the warp threads 210 below the reference path TI 30 of the lance 130.

[0067] Preferably, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path TI 30 of the lance 130, the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the lower edge of the shed corresponds to between 90% and 110% of the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the upper edge of the shed. The length between the harness 120 and the woven texture 200 is understood as the length between the point of said warp yarn present at the downstream end of the harness 120 and the point of said warp yarn present at the upstream end of the woven texture 200. Thus, significant differences in yarn length between the warp yarns to be removed placed above the reference path TI are avoided. 30of the lance 130 and the other warp threads placed below the reference path TI 30 of the 130 lance, which further reduces the risk of tension in the harness and facilitates the crossing between the warp threads to be taken out and the surface warp threads.

[0068] When the warp threads to be removed are suitably placed relative to the other warp threads 201 and relative to the reference path TI 30 of the lance 130, a second sub-step is carried out according to which the lance 130 is sent so that it passes through the loom 100 according to the reference path TI 30 without pulling weft thread 220. Thus, the lance 130 performs a “vacuum stroke”, also called an “airpick”. This vacuum stroke makes it possible in particular to correctly position the warp threads to be output in relation to the other warp threads 210, for example when the warp threads to be output have to pass through more than four layers of warp threads. The comb 160 can be folded after the empty shot is performed. The second sub-step is performed after the first sub-step.

[0069] The first and second substeps may be repeated several times in each weft column of the transition portion to be performed when warp yarns belonging to underlying warp yarn layers are to be removed from the weave through the upper surface warp yarn layer 210h. Thus, the first and second substeps may be performed for each warp yarn layer to be output through the upper surface layer 210h. Thus, by making an empty lance stroke 130 between each layer of warp threads to be output in the same weft column of the transition portion 202 to be produced, it is easier to position the layers of warp threads to be output relative to each other and to position the layers of warp threads to be output relative to the other warp threads 210, for example when the warp threads to be output must pass through more than four layers of warp threads. Making an empty lance stroke 130 for each layer of output warp threads, or for each part of the layer of output warp threads, also makes it easier to move the mass of warp threads to be output upwards by limiting the stresses and friction in the harness 120.Furthermore, in the same weft column of the transition portion 202 to be produced, the layers of warp threads to be taken out can be progressively removed one after the other, as illustrated in FIGS. 4 and. 5. Thus, by multiplying the number of first sub-steps for each weft column, the number of simultaneous crossings between the warp threads to be taken out and the warp threads of the surface layer is limited during each first sub-step, thus reducing the massive displacements of control threads in the harness 120 and consequently reducing the friction and stresses in the harness 120.

[0070] Figures 4 to 11 illustrate the second step of the method of the invention, according to which the transition portion 202 of the texture 200 is produced. In the example illustrated in Figures 4 to 11, it is desired to produce the woven texture 200 of Figure 3, the second portion 203 of which comprises six fewer layers of warp yarns than the first portion 201, by removing three layers of warp yarns 211, 212, 216 through the upper layer of warp yarns 210h and removing three layers of yarns of warp 213, 214, 215 through the lower warp yarn layer 210b. It is thus desired to produce a transition portion 202 between the first and second portions 201 and 203 comprising a first weft column N, in which two layers of warp yarns 211 and 212 are removed through the upper warp yarn layer 210h and two layers of warp yarns 213, 214 through the lower warp yarn layer 210b, and a second weft column N+1, in which a fifth layer of warp yarns 215 is removed through the upper warp yarn layer 210h and a sixth layer of warp yarns 216 through the lower warp yarn layer 210b.

[0071] In the example illustrated in Figure 4, the first step of weaving the first portion 201 of the texture 200 is completed and the second step of weaving the transition portion 202 of the texture 200 in the first weft column N is started. In Figure 4, the first and second sub-steps are carried out a first time for the first layer of warp threads 211 to be removed. Thus, the eyelets 121a crossed by the warp threads of the first layer of warp threads 211 to be removed are arranged above the eyelets 121a crossed by the other warp threads 210, so as to open a shed separating the first layer of warp threads to be removed 211 from the other warp threads 210. Thus, the shed also separates the first layer of warp threads 211 to be removed from the other layers of warp threads to be removed. 20 212, 213, 214, 215, 216.

[0072] Preferably, the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 are also moved in the vertical direction D v so as to place the first layer of warp threads to be output 211 above the reference path TI 30 of the lance 130 and so as to place the 25 more layers of warp yarns below the TI reference path 30 of the lance 130.

[0073] Furthermore, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path TI 30 of the lance 30 130, the length between the harness and the woven texture of the warp yarn of the upper surface warp yarn layer 210h which delimits the lower edge of the shed is between 90% and 110% of the length between the harness and the woven texture of the warp yarn of the first layer of warp yarns 211 to be removed which delimits the upper edge of the shed. Thus, significant differences in yarn length between the first layer of warp yarns 211 to be taken out and the upper surface layer of warp yarns 210h are avoided, which facilitates the crossing between the warp yarns to be taken out and the surface warp yarns without generating tensions in the harness, in particular between the eyelets and the warp yarns passing through them.

[0074] Furthermore, the movement of the guide device 170 from a first position to a second position after a rapier stroke is carried out so that, in each plane of the loom 100 perpendicular to the reference path TI 30of the lance 130, the length between the harness and the woven texture of a warp thread delimiting the lower edge of the shed when the guide device 170 is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp thread when it delimits the upper edge of the shed when the guide device is in the second position. Thus, the warp threads tilting from the lower edge of the shed to the upper edge of said shed after a lance stroke do not undergo excessive tension, thus facilitating thread crossings.

[0075] At the end of this first sub-step, the first layer of warp threads to be output 211 is arranged above the reference path TI 30of the lance 130 while the other layers of warp threads are arranged below the reference path TI3O of the lance 130. Thus, the other layers of warp threads to be taken out 212, 213, 214, 215, 216 are also arranged below the reference path Ti3o of the lance 130. A stroke of the lance 130 is then carried out empty in accordance with the second sub-step, as illustrated in FIG. 4.

[0076] Then, still in the first weft column N, the first and second sub-steps are carried out for the second layer of warp threads to be removed 212, as illustrated in Figure 5. Thus, the eyelets 121a crossed by the warp threads of the first and second layers of warp threads to be removed 211 and 212 are arranged above the eyelets 121a crossed by the other warp threads, so as to open a shed separating the first and second layers of warp threads to be removed 211 and 212 from the other warp threads 210. Thus, the shed also separates the first and second layers of warp threads to be output 211 and 212 from the other layers of warp threads to be output 213, 214, 215, 216.

[0077] Preferably, at least one of the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 is moved upwards in the vertical direction D v so as to place the first and second layers of warp yarns to be output 211 and 212 above the reference path Ti 30 of the lance 130 and so as to place the other layers of warp threads below the reference path Ti 30 of the lance 130. io

[0078] At the end of this first sub-step, the first and second layers of warp threads to be taken out 211 and 212 are arranged above the reference path TI 30of the lance 130 while the other layers of warp threads are arranged below the reference path Ti 30 of the lance 130. Thus, the other layers of warp threads to be taken out 213, 214, 215, 216 are also arranged below the path 15 reference Ti 30 of the lance 130. A stroke of the lance 130 is then carried out empty in accordance with the second sub-step, as illustrated in Figure 5.

[0079] In the example illustrated in Figures 4 to 10, only two layers of warp threads 211 and 212 are removed through the upper layer of warp threads 210h in the first weft column N of the transition portion 202 to be produced. It is of course not outside the scope of the invention if only one layer of warp threads or more than two layers of warp threads are removed through the upper layer of warp threads in a weft column of the transition portion to be produced. It is also not outside the scope of the invention if the layer of warp threads to be removed does not correspond to a complete layer of warp threads in the weaving loom. 25 weave.

[0080] The first and second sub-steps can be carried out for each layer of warp threads to be output through the upper layer of warp threads. However, it is of course not outside the scope of the invention if the first and second sub-steps are carried out for only a portion of the layers of warp threads output through the upper layer of warp threads.

[0081] For each weft column N, N+1 of the transition portion 202 to be produced, when the desired layers of warp threads have been taken out through the upper layer of warp threads 210h, the conventional weaving of the underlying layers of warp threads to be woven is carried out. The conventional weaving can 5 include unlinkings. If it is not desired to bring out warp threads through the lower layer(s) of warp threads in said weft column, conventional weaving of all layers of warp threads to be woven may be carried out. If it is desired to bring out warp threads through the lower layer(s) of warp threads in said weft column, conventional weaving of all underlying layers of warp threads to be woven, excluding the lower surface layers of warp threads, may be carried out, as illustrated in Figures 6 to 9.

[0082] The warp yarn layers 213 and 214 to be taken out through the lower surface warp yarn layer 210b in the vertical direction D v can also be removed by making empty lance strokes to properly uncross5 the warp threads.

[0083] For each weft column of the transition portion 202 to be produced, if it is desired to remove warp threads from the weaving through the lower surface warp thread layer 210b in the vertical direction D v , the sub-steps described below are carried out. O

[0084] According to a third sub-step, the warp threads to be removed, or the entire layer(s) of warp threads to be removed, are placed below the reference path Ti. 30 of the lance 130, and the warp threads to be woven and any other warp threads to be removed are placed above the reference path TI 30 of the lance 130. If warp threads have been brought out through the lower warp thread layer 210b in the previous weft columns, these brought out warp threads are arranged below the reference path TI 30 of lance 130 and below the warp threads to be removed during this third sub-step.

[0085] A shed is thus created separating on the one hand the warp threads to be removed, or the entire layer(s) of warp threads to be removed, from the warp threads to be woven and any other warp threads to be removed, said shed comprising the reference path TI 30 of the lance 130. This configuration is obtained by activating the wires control 121 of the harness 120, so as to arrange the eyelets 121a crossed by warp threads to be removed below the eyelets 121a crossed by the rest of the warp threads, with the exception of the warp threads already taken out through the lower surface warp thread layer 210b.

[0086] Preferably, this configuration is also obtained by arranging the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 at a vertical position D vallowing the warp threads to be removed, or the entire layer(s) of warp threads to be removed, to be placed below the reference path TI 30 of the lance 130, and so as to arrange the rest of the warp threads, with the exception of the warp threads already taken out through the lower surface warp thread layer, above the reference path TI 30 of the lance 130.

[0087] Preferably, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path TI 30of the lance 130, the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the lower edge of the shed corresponds to between 90% and 110% of the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the upper edge of the shed. The length between the harness 120 and the woven texture 200 is understood as the length between the point of said warp yarn present at the downstream end of the harness 120 and the point of said warp yarn present at the upstream end of the woven texture 200. Thus, significant differences in yarn length between the warp yarns to be removed placed above the reference path TI are avoided. 30 of the lance 130 and the other warp threads placed below the reference path TI 30 of the 130 lance, which further reduces the risk of tension in the harness and facilitates the crossing between the warp threads to be taken out and the surface warp threads.

[0088] Furthermore, the movement of the guide device 170 from a first position to a second position after a rapier stroke is carried out so that, in each plane of the loom 100 perpendicular to the reference path TI 30 of the lance 130, the length between the harness and the woven texture of a warp thread delimiting the lower edge of the shed when the guide device 170 is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp thread when it delimits the upper edge of the shed when the guiding device is in the second position. Thus, the warp threads switching from the lower edge of the shed to the upper edge of said shed after a rapier stroke do not undergo excessive tension, thus facilitating thread crossings.

[0089] When the warp threads to be removed are properly placed in relation to the other warp threads and in relation to the reference path Ti 30 of the lance 130, a fourth sub-step is carried out according to which the lance 130 is sent so that it passes through the loom 100 according to the reference path TI 30 without pulling weft thread 130. Thus, the lance 130 performs a “free stroke”, also called an “airpick”. This free stroke allows in particular to correctly position the warp threads to be taken out in relation to the other warp threads. The reed 160 can be folded down after the free stroke has been performed. The fourth sub-step is carried out after the third sub-step.

[0090] The third and fourth sub-steps can be repeated several times in each weft column of the transition portion 202 to be produced when it is desired to remove from the weaving through the upper surface warp yarn layer 210h warp yarns belonging to different warp yarn layers. Thus, the third and fourth sub-steps can be carried out for each layer of warp yarns to be taken out through the lower surface layer 210b. Thus, by carrying out an empty rapier stroke 130 between each layer of warp yarns to be taken out in the same weft column of the transition portion 202 to be produced, it is easier to position the layers of warp yarns to be taken out relative to each other and to position the layers of warp yarns to be taken out relative to the other warp yarns.Carrying out a free lance stroke 130 for each layer of warp threads output also makes it easier to move the mass of warp threads upwards by limiting the stresses and friction in the harness 120. Furthermore, in the same weft column of the transition portion 202 to be produced, the layers of warp threads to be output can be progressively output one after the other. Thus, by multiplying the number of third sub-. steps for each weft column, the number of simultaneous crossings between the warp threads to be taken out and the warp threads of the surface layer is limited during each third sub-step, thus reducing the massive displacements of control threads in the harness 120 and consequently reducing the friction and stresses in the harness 120.

[0091] In the example illustrated in Figure 10, the second step of weaving the transition portion 202 of the texture 200 is carried out in the second weft column N+1 after completing the first weft column N. In Figure 10, the third and fourth substeps are carried out for the fifth layer of warp yarns 215 to be removed. Thus, the eyelets 121a through which the warp yarns of the fifth layer of warp yarns 215 to be removed pass below the eyelets 121a through which the other warp yarns 210 pass except for the warp yarns of the third and fourth layers 213 and 214 already removed through the lower surface warp yarn layer 210b in the weft column N, so as to open a shed separating the fifth layer of warp yarns to be removed 215 from the other warp yarns to be woven or removed.

[0092] Preferably, the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 are also moved in the vertical direction D v so as to place the fifth layer of warp threads to be output 215 below the reference path TI 30 of the lance 130 and so as to place the other layers of warp threads to be woven or removed above the reference path Ti 30 of the lance 130.

[0093] Furthermore, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path TI 30of the lance 130, the length between the harness and the woven texture of the warp yarn of the fifth layer of warp yarns to be removed 215 which delimits the lower edge of the shed corresponds to between 90% and 110% of the length between the harness and the woven texture of the warp yarn of the lower surface warp yarn layer 210b which delimits the upper edge of the shed. Thus, significant differences in yarn length between the fifth layer of warp yarns 215 to be removed and the layer of yarns of lower surface warp 210b, which facilitates the crossing between the warp threads to be taken out and the surface warp threads without generating tensions in the harness, in particular between the eyelets and the warp threads passing through them.

[0094] Furthermore, the movement of the guide device 170 from a first position to a second position after a rapier stroke is carried out so that, in each plane of the loom 100 perpendicular to the reference path TI 30of the lance 130, the length between the harness and the woven texture of a warp thread delimiting the lower edge of the shed when the guide device 170 is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp thread when it delimits the upper edge of the shed when the guide device is in the second position. Thus, the warp threads tilting from the lower edge of the shed to the upper edge of said shed after a lance stroke do not undergo excessive tension, thus facilitating thread crossings. [OO95] At the end of this third sub-step, the fifth layer of warp threads to be taken out 215 is arranged below the reference path TI 30 of the lance 130 while the other layers of warp threads to be woven or removed are arranged above the reference path TI 30of the lance 130. Thus, the third and fourth layers of warp threads 213 and 214 taken out in the previous weft column N are also arranged below the reference path TI 30 of the lance 130, while the first and second layers of warp threads 211 and 212 taken out in the previous weft column N are arranged above the reference path Ti 30 of the lance 130. A stroke of the lance 130 is then carried out empty in accordance with the fourth sub-step.

[0096] In the example illustrated in Figures 4 to 11, only one layer of warp threads is removed through the lower layer of warp threads 210b in the second weft column N + 1 of the transition portion 202 to be produced. It is of course not beyond the scope of the invention if several layers of warp threads are removed through the lower layer of warp threads in a weft column of the transition portion to be produced. It is also not beyond the scope of the invention if the layer of warp threads to be removed does not correspond to a complete layer of warp threads in the loom.

[0097] The third and fourth substeps can be performed for each layer of warp yarns to be output through the lower layer of warp yarns. The third and fourth substeps can also be performed only for a portion of the layers of warp yarns output through the lower layer of warp yarns.

[0098] Preferably, as illustrated in Figures 4 to 11, when the last rapier stroke 130 of a weft column N has been made in the lowest layers of warp threads in the vertical direction D v , the first lance stroke 130 is also carried out in the following weft column N+l in the lowest layers of warp threads in the vertical direction D v . Similarly, when the last lance stroke 130 of a weft column has been made in the highest layers of warp threads in the vertical direction, the first lance stroke 130 is also made in the following weft column in the highest layers of warp threads in the vertical direction D v This limits the massive movements of layers of warp threads in the harness and consequently reduces friction and stress on the control threads 121.

[0099] As the transition portion 202 is woven, more and more yarns 211 to 216 are brought out through the upper 210h and lower 210b surface warp yarn layers, and must be kept away from the yarns being woven. Thus, the greater the number of layers of brought out yarns 211 to 216, the more it is necessary to enlarge the amplitude of the shed opening, in order to properly position the brought out yarns relative to the yarns to be woven. This prevents crossings between the yarns to be woven and the brought out yarns, thereby reducing friction and the risk of defects. Increasing the angle of the shed opening is achieved by keeping the eyelets through which the brought out yarns pass in a very high or very low position in the harness.The increase in shed opening is particularly significant when the number of yarn layers exiting through one of the upper or lower surface layers is greater than four. Indeed, when the number of yarn layers exiting through one of the. upper or lower surface layers is for example greater than four, the friction between the threads increases greatly if the shed opening is not adjusted.

[0100] According to a particular embodiment of the invention, a binding 5 of the warp threads exited can be carried out. Thus, when producing the weft columns N and N+1 of the transition portion 202 of the texture 200, one or more available weft threads 220 can be used in the weft column N or N+1 of the transition portion 202 in order to bind the warp threads exited using the vacuum lance strokes in said weft column N or N+1.

[0101] The woven texture 200 obtained by the method of the invention may correspond to a swollen texture, which will be compacted to obtain a compacted texture with dimensions chosen and adapted to the use which will be made of said texture.

[0102] Thus, it is preferable to have a sufficient spacing between the lower guide bar 171 and the upper guide bar 172 of the device. 15 guide 170 so as not to deform the swollen texture 200, and to ensure that the texture will be correctly positioned in the correct vertical position during weaving in order to facilitate the crossing between the warp threads to be taken out and the layers of surface warp threads. Therefore, preferably, during the weaving process according to the invention, the spacing between the lower guide bar 171 and the bar 20 upper guide 172 of the guide device 170 must always be greater than a minimum value H 170determined along the vertical direction D v , as illustrated in Figures 4 to 9. This minimum value HI7O of spacing of the guide bars 171 and 172 preferably corresponds to the product of the desired thickness for the compacted texture by 1.45. Indeed, it is estimated that the desired thickness for the 25 compacted texture corresponds to approximately 40% of the 200 expanded texture present on the loom.

[0103] In particular, it may be desirable that the compacted texture obtained has a volumetric rate of threads of at least 58%. Thus, the minimum value H i 70 spacing of the guide bars 171 and 172 is preferably calculated as follows, 30 where E58° / O is the desired thickness for the compacted preform with a fiber volume ratio of 58%:

[0105] Furthermore, the execution of warp thread exits through the surface layers and the correct execution of the free lance strokes require large height differences between the eyelets. The large amplitudes between the lowest and highest eyelets in the harness during warp thread exits or during free lance strokes can create significant tensions if the spacing between the guide bars 171 and 172 remains fixed. Thus, preferably, when performing numerous warp thread exits or a free lance stroke, the spacing between the guide bars 171 and 172 can be increased by a certain value to facilitate the warp thread crossings and thus the warp thread exits. Thus, the guide bars 171 and 172 can be movable relative to each other in the vertical direction D v .

[0106] According to a particular embodiment of the invention, the spacing of the guide bars is adjusted during each rapier stroke, including during empty rapier strokes. Thus, the spacing of the guide bars is adjusted each time the rapier passes through the loom.

[0107] When weaving a weft column, when making free rapier strokes to remove layers of warp yarns through the upper surface warp yarn layer, the spacing between the guide bars is increased for each free rapier stroke. Thus, the spacing value of the guide bars 171 and 172 is HI7O + hi in the vertical direction D v during the first empty lance stroke, hi being a positive height, as illustrated in Figure 4. The value of the spacing of the guide bars 171 and 172 is then HI7O + hi + h2 in the vertical direction D vduring the second empty lance stroke, h2 being a positive height, as illustrated in Figure 5.

[0108] Preferably, in order to further facilitate yarn crossings, the increase in the spacing of the guide bars when removing one or more layers of warp yarns through the upper surface warp yarn layer is carried out while the lower guide bar is fixed. Thus, only the upper guide bar, which is closest to the surface warp yarn layer upper, is movable to allow the spacing between the guide bars to be increased when withdrawing one or more layers of warp yarns through the upper surface warp yarn layer.

[0109] When the empty rapier strokes for removing layers of warp yarns through the upper surface warp yarn layer are completed and the insertion of the weft yarns begins, the spacing between the guide bars is decreased for each rapier stroke carrying a weft yarn. Thus, the spacing value of the guide bars 171 and 172 is HI 70 + hi + h2- h3 in the vertical direction D v when inserting the first weft thread, h3 being positive, as illustrated in Figure 6. The value of the spacing of the guide bars 171 and 172 is then HI7O + hi + h2- h3- h4 in the vertical direction D v when inserting the second weft thread, h4 being positive, as shown in Figure 7.

[0110] The value of the spacing between the guide bars can be decreased until the minimum value HI7Q is obtained. Preferably, decreasing the spacing of the guide bars until the minimum value HI is obtained 70 is carried out while the upper guide bar is fixed. Thus, only the lower guide bar is movable to allow the spacing between the guide bars to be reduced until the minimum value HI7Q is reached. [YES] Preferably, if n free lance strokes are made to remove one or more layers of warp yarns through the upper surface warp yarn layer, the minimum gap value HI is found 70 during the n-th insertion of weft thread. In the example illustrated in figures 4 to 7, hi = h2= h3= h4: we therefore find the minimum spacing value HI 70 when inserting the second weft thread.

[0112] When continuing to insert weft threads after reaching the minimum spacing value HI7O between the guide bars, the spacing of the guide bars is maintained at said minimum spacing value HI 70 for the following insertions of weft threads. In order to avoid tensions in the threads as described above, the value of the spacing of the guide bars is maintained while said guide bars are movable in the vertical direction D v to adapt to successive crowd openings.

[0113] When making free lance strokes to remove layers of warp yarns through the lower surface warp yarn layer, the guide bar spacing may be increased again at the last weft yarn insertion(s) before the free lance strokes. Preferably, if making m free lance strokes to remove one or more layers of warp yarns through the lower surface warp yarn layer, the guide bar spacing value is increased for the last m weft yarn insertions.

[0114] Thus, the spacing value of the guide bars 171 and 172 is HI7O + h5 in the vertical direction D v during the penultimate insertion of a weft thread, h5 being a positive height, as illustrated in Figure 8. The value of the spacing of the guide bars 171 and 172 is then HI7O + h5 + h6 in the vertical direction D vat the last insertion of a weft thread, h6 being a positive height, as illustrated in Figure 9. [O115] Preferably, the re-increase of the spacing of the guide bars for the last insertion(s) of weft threads is carried out while the lower guide bar is fixed. Thus, only the upper guide bar is movable to allow the re-increase of the spacing between the guide bars.

[0116] When making the vacuum lance stroke(s) to remove layers of warp yarns through the lower surface warp yarn layer, the spacing between the guide bars is decreased for each vacuum lance stroke (not shown).

[0117] The guide bar spacing can be reduced until the minimum value HI7O is obtained for the last empty lance stroke. Preferably, reducing the guide bar spacing until the minimum value HI is obtained 70 is carried out while the upper guide bar is fixed. Thus, only the lower guide bar is movable to allow the reduction of the spacing between the guide bars until the minimum value HI is reached 70 .

[0118] Thus, within the framework of the method of the invention, the first portion 201 of the texture 200 is woven during the first step and the transition portion 202 of the texture 200 is woven during the second step.

[0119] In the second step, for each frame column of the portion of 5 transition 202 to be carried out and if it is desired to remove warp threads through the upper surface layer 210h, the first and second sub-steps are carried out for each set of warp threads to be removed through the upper surface layer 210h. Indeed, the first sub-step makes it possible to properly arrange the warp threads on either side of the reference path eno achieving the desired shed, and the second sub-step corresponds to an empty lance stroke.

[0120] In the second step, for each weft column of the transition portion 202 to be produced and if it is desired to remove warp threads through the lower surface layer 210b, the third and fourth sub-steps are carried out for each set of warp threads to be removed through the lower surface layer 210b. Indeed, the third sub-step makes it possible to properly arrange the warp threads on either side of the reference path by producing the desired shed, and the fourth sub-step corresponds to an empty lance stroke. O

[0121] In the example described above, for reasons of simplification, the exit of the warp threads by entire layer is described in one go. However, in practice, a layer of warp threads is generally exited in at least two goes, or only a part of the layer of warp threads is exited. For example, to exit an entire layer of warp threads, a part5 of said layer is first exited by making one stroke of the lance while empty, then the other part of said layer is exited by making another stroke of the lance while empty.

[0122] In the example illustrated in Figures 3 to 11, the surface warp yarn layers are continuous and made of the same warp yarns along the entire length of the texture. However, it is not outside the scope of the invention if the surface warp yarn layers are made of different warp yarns along the length of the texture.

[0123] The warp and weft yarns used in the present invention may be fibers, for example carbon, glass or ceramic fibers, or a mixture of such fibers. In particular, the woven texture may be made from fibers made of the following materials: silicon carbide, alumina, mullite, silica, an aluminosilicate, a borosilicate, or a mixture of several of these materials.

[0124] The woven texture can thus be intended to form the fiber reinforcement of a composite material part, for example a ceramic matrix composite (CMC) or organic matrix composite (OMC) material part. The woven texture can thus be intended to form the fiber reinforcement of a composite material part of an aeronautical engine, for example an aeronautical engine blade. Indeed, the use of organic matrix composite (OMC) and ceramic matrix composite (CMC) materials on aeronautical engines, replacing metallic materials, contributes to optimizing aircraft performance, in particular by improving the efficiency of the turbomachine and by reducing the overall mass of the engine, thus significantly reducing harmful emissions to the environment.

Claims

Claims

1. Method for three-dimensional weaving of a texture (200) between a plurality of layers of warp threads (210) superimposed in a vertical direction (D v ) and a plurality of weft threads (220) extending in a horizontal direction (D H ), the weaving being carried out by means of a loom (100) comprising a plurality of control threads (121), a first end of each control thread (121) being connected to a Jacquard mechanism (110) capable of moving the control threads (121) in the vertical direction (D v) between a neutral position and at least one opening position of the warp threads (210), each control thread (121) being further provided with an eyelet (121a) crossed by a warp thread (110), the weaving loom (100) further comprising at least one lance (130) present downstream of the control threads (121) capable of crossing the weaving loom (100) along a fixed horizontal reference path (TI 30 ) and drawing a weft thread (220) from a bobbin (140), characterized in that the method further comprises at least one warp thread output step comprising: - the displacement in the vertical direction (D v) of all or part of the warp threads of at least one underlying warp thread layer (211, 212, 213, 214, 215, 216) of the plurality of warp thread layers, said displaced warp threads (211) being intended to be taken out of the texture (200), over a determined distance extending beyond a warp thread layer (210h; 210b) present on the surface of the plurality of warp thread layers (210), so that the displaced warp thread(s) (211) are arranged above the reference path (TI 30 ) and that the remainder of the undelivered warp threads are arranged below the reference path (TI3O), OR so that the displaced warp thread(s) (211) are arranged below the reference path (TI 30 ) and that the rest of the unreached warp threads are arranged above the reference path (TI 30 ), Then - the crossing of the loom (100) by the lance (130) according to the reference path (TI 30) without pulling any weft thread.

2. Method according to claim 1, wherein when weaving at least one weft column (N; N+1) a plurality of underlying warp yarn layers (211, 212; 213, 214; 215; 216) is intended to be taken out of the texture (200) beyond one of the warp yarn layers (210h, 210b) present on the surface of the plurality of warp yarn layers (210), the following step of taking out warp yarns being repeated for each warp yarn layer to be taken out (211, 212; 213, 214; 215; 216) beyond said layer (210h, 210b) present on the surface: the displacement in the vertical direction (D v) of the warp yarn layer to be taken out (211, 212, 213, 214, 215, 216) over a determined distance extending beyond the warp yarn layer present on the surface (210h, 210b) of the plurality of warp yarn layers (210), so that the displaced warp yarn layer (211, 212, 213, 214, 215, 216) is arranged above the reference path (TI 30 ) and below the previously moved layers of warp threads intended to be taken out of the texture (200) and that the rest of the untaken warp threads are arranged below the reference path (TI 30 ), or so that the displaced warp yarn layer (211, 212, 213, 214, 215, 216) is arranged below the reference path (TI 30 ) and above the previously moved layers of warp threads intended to be output from the texture (200) and that the rest of the unoutputted warp threads are arranged above the reference path (TI 30); then the crossing of the loom (100) by the lance (130) according to the reference path (TI 30 ) without pulling any weft thread.

3. A method according to claim 1 or 2, wherein the step of taking out warp threads further comprises, after the rapier (130) has passed through the loom (100) without drawing any weft thread: - the movement in the vertical direction (D v ) of a portion of the displaced warp threads or of a portion of the displaced layer so that said portion of the displaced warp threads or of the displaced layer is arranged below the reference path (TI 30 ) and that the other part of the displaced warp threads or the displaced yarn layer is arranged above the reference path (TI 30 ) , Then - the crossing of the loom by the lance according to the reference path (TI 30) by pulling a weft thread (220) so as to bind the displaced warp threads together.

4. A method according to any one of claims 1 to 3, wherein the loom (100) further comprises a guide device (170) present downstream of the plurality of control threads (121) and the rapier (130), the guide device (170) being able to move in the vertical direction (D v ) so as to move the woven texture (200) up or down relative to a horizontal reference plane (P H ) including the reference path (TI 30 ).

5. The method of claim 4, wherein the guide device (170) comprises an upper guide bar (172) and a lower guide bar (171) configured to be positioned in contact with the woven texture (200) and on either side of said texture (200) in the vertical direction (D v), the minimum value of the spacing between the guide bars (171, 172) corresponding to the thickness of the uncompacted woven texture (200).

6. A method according to claim 5, wherein the spacing between the guide bars (171, 172) increases when moving in the vertical direction (D v ) of all or part of the warp threads (211, 212, 213, 214, 215, 216) intended to be taken out of the texture (200) over a determined distance extending beyond a layer of warp threads present on the surface (210b, 210h) of the plurality of layers of warp threads (210).

7. A method according to claim 5 or 6, wherein the guide bars (171, 172) of the guide device (170) are configured to move in the vertical direction (D v ) depending on the vertical position of the eyelets (121a) of the harness (120) when moving in the vertical direction (D v) of all or part of the warp threads (211, 212, 213, 214, 215, 216) intended to be taken out of the texture (200) over a determined distance extending beyond a layer of warp threads present on the surface (210h, 210b) of the plurality of layers of warp threads (210), so that in each plane of the loom (100) perpendicular to the reference path (TI 30 ), the length between the harness (120) and the woven texture (200) of the lowest warp yarn located above the reference path (TI 30 ) corresponds to between 90% and 110% of the length between the harness (120) and the woven texture (200) of the highest warp yarn located below the reference path (TI 30 ).

8. Method according to any one of claims 4 to 7, the guide device (170) being configured to move between a first position and a second position in the vertical direction (D v) depending on the vertical position of the eyelets (121a) of the harness (121) after the movement in the vertical direction (D v ) of all or part of the warp threads (211, 212, 213, 214, 215, 216) intended to be taken out of the texture (200) over a determined distance extending beyond a layer of warp threads (210h, 210b) present on the surface of the plurality of layers of warp threads (210), so that in each plane of the loom (100) perpendicular to the reference path (TI 30 ), the length between the harness (120) and the woven texture (200) of the highest warp thread located below the reference path (TI 30 ) when the guide device (170) is in the first position is between 90% and 110% of the length between the harness (120) and the woven texture (200) of said warp yarn when it is the lowest located above the reference path (TI 30) when the guide device (170) is in the second position.

9. A method according to any one of claims 1 to 8, wherein the warp (210) and weft (220) yarns are carbon, glass or ceramic fibers.

10. Method according to any one of claims 1 to 9, in which the woven texture (200) is intended to form a fibrous reinforcement for a composite material part of an aeronautical engine.

Images