EP2087157B1 - System for weaving a continuous angle - Google Patents

Abstract

The loom (20) has drafting units drafting threads (28) on respective sides (22A, 22B) for forming laps (24A, 24B) between the sides and another two sides (22C, 22D). Shed forming systems form sheds on the laps at the sides (22A, 22B), respectively, where one system has opening elements (26B) for handling the threads and the other system is operated, by tilting, directly on drafting hooks (26A). A reel (60) contains a weft thread rolling (34) weaving the laps. A receptacle (62) is placed between the former sides and the laps to hold the reel. Flattening reeds flatten a pick traversing the laps.

Description

TECHNICAL AREA

The invention relates to the field of weaving, in particular of technical textiles in which at least one thread of the weft of the fabric forms a continuous angle, for example in relief.

More generally, the invention relates to a system that allows the insertion of several plies and the weaving in parallel of these plies, preferably using the same weft yarn. The various elements of the loom are optimized to reduce its size and facilitate the various weaving steps.

The system according to the invention is particularly suitable for a three-dimensional surface weaving making it possible to obtain structures extracted from hexahedrons, in particular trihedral angles, woven continuously between the various edges.

STATE OF THE PRIOR ART

Weaving has been used since ancient times to produce fiber-based fabrics organized in the form of yarns. In spite of the mechanization and automation of the process or its use for so-called "technical" textiles, for example as reinforcements of composite materials, the present weaving process is based on the same bases as before and, as such, has evolved little.

In fact, all the woven fabrics comprise an interlacing of yarns divided into two categories: the "warp threads" are threads parallel to the edges of the fabric, and they are crisscrossed, in a pattern called "armor", with a perpendicular series of "Weft threads". The simplest armor consists of an alternation in which each weft thread passes successively above and below a warp, with a shift from one frame to another ("plain weave").

A loom for weaving a fabric in the weft of which at least one yarn forms an angle is known from JP 626 43 25 A .

To make a weaving 1, as schematized on the figure 1 the warp yarns 2 are firstly wound on the same support, the "beam" 3, parallel to each other and over a width that will correspond to the width of the fabric 1; a "creel" is used to facilitate this operation in the case of fragile materials, but has a significant footprint. The weft thread 4 will be passed between the warp threads 2, each passage corresponding to a "pick". Depending on the type of picking vector, the web 2 'of warp threads 2 may be prepared (for example by gluing) in order to increase its mechanical strength, in particular to friction.

The passage of each pick is facilitated by making a "crowd" 5 in the web 2 ', that is to say by raising or lowering some warp threads 2 relative to the others, so that a space angular passage 5 is created. To create the crowd 5, the warp threads 2 are retracted into heddles 6, which will undergo the movement perpendicular to the ply 2 'resulting from the beam 3. Various mechanisms (frame, Jacquard) allow to create crowds according to the required armor.

The insertion of the pick 4 can be done by various methods. An old conventional method comprises projecting, across the sheet, a shuttle 7, a tool that holds a bobbin 8, the latter containing a winding of a certain length of weft yarn 4. However, this passage generates friction . If gluing sometimes makes it possible to increase the mechanical strength, this solution can not be adopted for all textiles, and in particular, not for reinforcing threads for composite structures with high strength.

Other systems of passage of the pick have been developed. In particular, jets of fluid (water or gas) can carry the wire on the other side of the sheet; it is also possible to use a lance or two lances that extend over half of the web each: a lance captures the weft yarn to transmit it, in the middle of the web, to the other. These solutions, however, allow the passage of only a finite and short length of wire. However, in some uses, the continuity of the weft yarn is important.

Finally, each time a pick is passed through the crowd, a comb 9 in the teeth of which are taken the warp yarns 2 is packed on the fabric 1 already formed, while the rails 6 are actuated to create another crowd 5 which depends on the armor.

It is clear that the preparation of the web of warp threads is long. In particular, the insertion of the warp yarns 2 in the heddles 6 must be carried out with precision, as well as the setting up of the comb 9. These steps may also generate alterations of the yarn 2 due to friction, which are particularly problematic in the case of carbon threads. In addition, the presence of the smooth 6 and comb 9 involves a weaving device of large vertical dimensions, particularly detrimental when, for example for technical textiles, only a finished and short length of fabric 1 is made.

For example, in the aeronautical field, composite structures are developed to replace the usually metallic elements of box structures (also known as " box "). For the junctions, "corner of the trunk" (or " corner fittings ") are necessary, whose geometry seems simple: a corner of trunk classic 10, illustrated in figure 2 , comprises for example three two-dimensional walls 12, 14, 16, substantially planar, forming a trirectangle trihedral angle (type "half-cube").

"Three-dimensional" weaving processes have certainly been developed in which the product resulting from the weaving operation comprises an intercrossing of yarns arranged along the three directions of space. In particular, Aérotiss® processes make it possible to weave glass and carbon fibers with multilayer interlacing which can be used to achieve aircraft leading edge skins, among others. For parts of more complex shape, the braiding can be used: it allows to make parts directly in hollow form on a suitable mandrel.

A textile reinforcement of the trunk corner reinforcement, like most three-dimensional two-dimensional wall forms, can however only be made on existing machines from a "flat" version of the walls and through a seam 10z between at least two faces 14, 16.

But a seam is a reported element, more or less fragile, which poses unsuitable mechanical resistance problems in aeronautics. In addition, the continuity of the fibers according to the different planes is not ensured, the reinforcement function is not fully realized. In fact, the trunk corners, even for composite box structures, are manufactured by a metal support.

Furthermore, complex stresses may require continuity of the yarn in other woven pieces, including for a yarn forming an angle within the fabric, that is to say a yarn being over a certain length parallel to an edge of the piece and on a consecutive length parallel to another edge. This continuity can be fundamental for composite reinforcing technical textiles, and in particular in aeronautics.

It thus appears that the looms are perfectible in particular as regards their use for the production of technical textiles.

STATEMENT OF THE INVENTION

The invention proposes a device capable of producing structures comprising a plurality of orthogonal faces between them and connected in at least three edges in a continuous manner, for example of trihedral angles, without seam.

More generally, the invention relates to a loom for insertion of wire forming an angle within the weave.

The loom according to the invention thus comprises first and second means for retrieving wires to form two intersecting webs, first and second means for forming crowds in the two webs, first and second means for tamping the picks in the two layers, for example combs secured to one another.

As one of the plies is formed during the weaving of the other, at least one, at least two, of the at least two tucking means is open, consisting of hooks. One of the two shedding systems, preferably both, is also open, i.e. it includes open wire handling members. Advantageously, in order to reduce the bulk, the shifting of the wires to form the shed is effected by means of a rod secured to the handling elements, preferably the tying hooks, which pivots about an axis and allows a mobilization of the son when a pressure is exerted on it. Advantageously, a system tilting between two support positions on the rod allows the formation of the crowd: in a rest position, an initialization axis presses all the rods to align them, and in an actuating position, selected thrust elements in the other direction press on some rods so as to shift some hooks relative to others. The rocker is preferably made around the same pivot axis as the rods.

In addition, the pick is inserted continuously between the two layers, and the loom according to the invention comprises a coil which can contain a winding of weft of sufficient length. The loom is provided with means for receiving the bobbin when it is inserted at the corner between the two plies, preferably a receptacle provided with temporary holding means which may furthermore comprise means for guiding the bobbin to ensure a frictionless insertion.

Advantageously, the pick is inserted in a manner directed by temporarily securing the coil with insertion lances defining a weaving direction in each sheet. The holding receptacle of the coil is then advantageously mounted so as to rotate to orient its opening in the direction of each lance used.

In order to perform a three-dimensional surface weaving, the loom can be provided with means allowing the offset of a woven surface relative to the webs, for example a frame movable in a direction perpendicular to the frame of the craft.

In order to compensate for the various pull-ups and in particular to allow the weaving of non-extensible carbon-type threads, advantageously, the tying hooks are associated with spring-type tensioning means, individually and / or collectively.

It is possible to provide to weave a third side of a web, that is to say a second (or third) corner by providing a reel receiving sheath, optionally accompanied by an insertion lance. In addition, tying hooks on one or two other sides of the craft frame can also be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

• La figure 1, déjà décrite, illustre schématiquement un procédé de tissage classique.
• La figure 2 représente schématiquement un (pli tissé pour former un coin de malle.
• La figure 3 représente un métier à tisser selon un mode de réalisation de l'invention.
• La figure 4 montre un système de formation de foule utilisé de préférence dans un métier selon l'invention.
• Les figures 5A à 5H illustrent un procédé de tissage tridimensionnel surfacique avec un métier selon l'invention.

Other characteristics and advantages of the invention will emerge more clearly on reading the following description and with reference to the appended drawings, given solely by way of illustration and in no way limiting.

• The figure 1 , already described, schematically illustrates a conventional weaving process.
• The figure 2 schematically represents a woven fold to form a corner of trunk.
• The figure 3 represents a loom according to one embodiment of the invention.
• The figure 4 shows a crowd forming system preferably used in a loom according to the invention.
• The Figures 5A to 5H illustrate a three-dimensional surface weaving process with a loom according to the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

According to the invention, it is possible to manufacture a three-dimensional woven fold with thread continuity between each adjacent face 12, 14, 16 of the fold. This allows the formation of one or more corners without any other step than weaving. More generally, even for "flat" weaving, the loom according to the invention allows to insert into the weft wire at an angle between two portions of the wire respectively parallel to the two edges of the fabric.

For this purpose, a weft yarn inserted in a weaving web must be able to be inserted in two directions, and therefore two weaving webs at the same time must be able to be formed.

The loom 20 according to the invention therefore comprises, on two adjacent sides of its frame 22, preferably orthogonal to each other, two thread taking-in means, at least one of the two being open so as to form the corresponding sheet. at the same time as weaving: see figure 3 .

In fact, the first ply 24A can, as usual, be stretched between the first side 22A and the third opposite side 22C of the frame, to be woven by a weft thread. The frame of the loom comprises on a second side 22B hooks 26B for passing a wire 28 around to form a secondary web 24B: during weaving of the primary web 24A, the primary weft son 28 are extended to bypass the hooks 26B, and thus form a second ply 24B forming a closed angle 30, for example 90 ° if the weaving is orthogonal, with the first ply 24A at the woven piece 32. It will be possible to weave this angle 30 continuously by a single weft thread; in particular, once the first face 32 is woven, the secondary weft thread 34, instead of being fixed on a hook, can be used to weave the formed secondary ply 24B, the initial weft threads 28 then working in warp yarns .

Advantageously, the primary ply 24A is put in place by means of the same hook ply formation system 26A: the opening of this system allows the continuity of the warp yarns forming the ply 24A also, particularly advantageous in the case of fiber weaving for reinforcing composite structures, for example carbon or aramid.

Preferably, the hooks 26A, 26B are individually associated with a tensioning system 36A, 36B loop for working 28 son stretch; a regulation system 38 in collective tension son can further guarantee the tension of the fabric 32: the function "reserve son" of the beam or creel is replaced by a collective voltage regulator son 38 having a recoil X, Y sufficient to the dimensions of the final preform.

Thus, according to the invention, the initial tying of the warp son is done, manually for example, in a first series of open frames 22A, comprising attachment hooks 26A optionally on each side 22A, 22C. The weaving of this sheet 24A allows the formation of the first face 32: similar to conventional two-dimensional weaving, the method comprises the insertion of weft thread 28 into the first series of threads 24A set up on the loom 20, which is working in chain (primary warp threads). To this end, the loom 20 includes a first shedding system, which may be conventional or, preferably, will be the same as that of the second mat and described later.

Parallel to the weaving of the first face 32, which is made according to a conventional technique and for example with plain weave, a second ply 24B is formed; in the case where the armor of the first face 32 is orthogonal, this second ply 24B is in particular perpendicular to the first face 32. For this purpose, the weft threads 28 used for the first face 32 pass through the ply 24A and then make a loop at their respective hook 26B, then cross the frames again in the other direction. Depending on the desired shape, it is possible to tension these primary weft son on the frame 22 at a fourth side 22D opposite the second side 22B, and advantageously also provided with open tying hooks ensuring continuity of the wire (in thus forming a fourth web 24D), or to take the weaving directly in the other direction at the opposite edge of the woven piece 32.

Thus, a plane fabric 32 is obtained thanks to the system of open frames, together with a tuck in a second frame system 22B with the son used in weft (or picks) 28, that is to say one side 32 is woven while retracting the weft threads 28 which will be used in a chain in a following phase to insert secondary weft threads 34.

The secondary ply 24B being intended to be woven, a shed must be able to be opened between the strands 28: the loom according to the invention comprises a second shedding formation system 40 traversing the ply 24B, for example parallel to the second edge 22B of the frame . The crowd forming system 40 is preferably fully open to simplify the formation of the web 24B; it may also be smooth two separable parts, the first part being open during the tapping of the web and being closed by the second part once the web formed, to proceed as usual.

Preferably, the opening of the crowd is done without any frame or Jacquard mechanism, for a footprint less than that imposed by this type of system: the selection of the son 28, and therefore their vertical movement, is done through a system of flip, preferably directly on the hooks 26B. Advantageously, the crowd forming system of the primary sheet 24A also operates by tilting, directly on the tying hooks 26A: this is particularly suitable for a small footprint as encountered in weaving units associated with production units of composite structures.

For this purpose, as illustrated in figure 4 the hooks 26 are each secured to one end of a handling rod 42; the other end 44 of the rod 42 is for example coupled to the tensioning system 36, 38.

Between the two ends 26, 44 of the rod is an axis 46 allowing the pivoting of the handling rod 42 by a thrust exerted on a portion thereof, to raise or lower the hook 26. Advantageously, the rods 42 are guided by a ramp 48, which can form the edge 22 of the frame of the loom 20.

To tilt the hook 26 upwards or downwards, preferably, a latch system 50 bears on one part or the other of the rod 42. Thus, the latch system 50 comprises an initialization axis 52 which actuates all the rods 42 together to align them, thereby creating an initial position of the hooks 26, preferably in a low position which corresponds to the plane of the web 24 warp son.

The flip-flop system 50 furthermore comprises a device 54, which selects the hooks 26 'which must rise according to the armor to be produced, then raises them to form the shed 56 by pressing on the other part of the rod. actuation 42 corresponding. The selector device 54 may thus comprise pushing elements 58 that can take two positions depending on their activation, for example retractable: during the formation of the crowd 56, the selector device 54 activates the elements 58 accordingly, they exert a pressure on their rod 42, to lift the hooks 26 '. Then, the selection is modified according to the armor to be produced, by mechanical or electronic selection of the pushing elements 58.

The initialization axis 52 and the thrust elements 58 are connected by means such that the actuation of the activated thrust elements 58 causes a withdrawal from the initialization axis 52. In particular, this coupling also functions by flip-flop and comprises a rocker 50 pivoting about the same axis 46 as the handling rods 42.

1. a) Le système de sélection 54 des crochets 26 est en position haute, l'axe de descente 52 est en position basse. Les crochets 26 sont donc en position initiale (ou position basse).
2. b) Une rotation positive de la bascule 50 permet au système de sélection 54, 58 de sélectionner les crochets 26' puis de les lever. Les crochets 26' pivotent alors en appui sur la rampe 48 en position haute. La foule 56 est ainsi ouverte, un fil de trame peut alors être introduit et tassé.
3. c) La foule 56 peut se refermer. Pour cela, l'axe de descente 52 entraîné par la bascule 50 dans sa rotation négative, abaisse les crochets levés 26'. Tous les crochets 26 se retrouvent ainsi à leur position initiale (ou position basse), la foule est fermée.

The kinematics is thus composed of two main movements: a positive rotation along the rocking axis 46 of the crowd forming system to open the crowd 56 and a negative rotation along the axis 46 closing the crowd.

1. a) The selection system 54 hooks 26 is in the high position, the axis of descent 52 is in the low position. The hooks 26 are therefore in the initial position (or low position).
2. b) A positive rotation of the latch 50 allows the selection system 54, 58 to select the hooks 26 'and then lift them. The hooks 26 'then pivot in support on the ramp 48 in position high. The crowd 56 is thus open, a weft yarn can then be introduced and packed.
3. c) The crowd 56 can close. For this, the down axis 52 driven by the latch 50 in its negative rotation, lowers the raised hooks 26 '. All the hooks 26 are thus found in their initial position (or low position), the crowd is closed.

Admittedly, according to this illustrated embodiment, the crowds 56 are formed by even number of warp threads 28, but this poses no problem for technical textiles, and in particular reinforcements of composite structures. The system 40 would, however, be adaptable for an odd armor, for example by looping around two hooks 26 consecutive during the tucking. It would also be possible to couple the actuating rods 42 to other wire handling elements, for example a series of hooks placed around each wire 28 within the ply 24.

With the loom 20 according to the invention, once the first face 32 woven, the weaving is done simultaneously on the two layers created 24A, 24B (primary warp son and secondary warp son), with a non-rectilinear insertion of weft thread 34.

To ensure the continuity of the secondary weft thread 34 during formation of the wedge 30, the pick must include a sufficient length of thread; conventionally, the weft thread 34 is in the form of a winding around a spool 60. Means are provided in the loom 20 to allow a deposit temporary of the coil 60 of weft thread 34 between the two plies 24A, 24B, in order to selectively actuate the insertion means in the first 24A or the second ply 24B. In particular, the depositing means 62 comprise a cylindrical receptacle adapted to the size of the coil 60, that is to say a sleeve 62 in which the coil 60 can be placed temporarily; the sheath 62 is advantageously provided with suitable holding means, for example a clamp coupled to a tip. The sheath 62 may also be provided with guiding means for preventing friction or shock between the coil 60 and the walls of the sheath 62 during insertion; for example, the spool 60 is provided with a pointed appendix (unitary or added) at the end entering the sheath 62, which is provided with an orifice of complementary shape, opening or not, allowing a progressive readjustment of the position of the coil 60 by guiding the appendix in the orifice.

The sheath 62 is placed in the frame 22, between the first and second sides 22A, 22B and the plies 24A, 24B. Advantageously, since the pick 34 is inserted in a predetermined direction in each sheet 24, the sleeve 62 is rotatably mounted so that its opening can face the two directions of insertion of the pick 34.

Preferably, the insertion of the pick 34 is performed by means of a directional lance 64 in each sheet 24. Each lance 64 then comprises means for coupling with each other. temporarily to the coil 60, and to put it in the sheath 62 when it succeeds, thus allowing the transfer of the coil 60 from one lance to the other (multiple insertions system of picks). Thus, continuity of the son can be ensured while avoiding damage to the son constituting the crowd: for weaving, the first spool 64A carrying the coil 60 is introduced into the open shed, for example orthogonally to the web 24A. At the end of the sheet of warp yarn 24A, the lance 64A then deposits the spool 60 in the sleeve 62, then leaves the crowd empty to return to the initial position. The crowd formation system then closes, a tamping comb is eventually used, forming the fabric; the sheath 62 rotates towards the second direction perpendicular to the other ply 24B and a vacuum lance 64B picks up the spool 60 to retrace the second crowd.

This transfer makes it possible to direct the thread and thus to weave at an angle. Of course, depending on the number of webs 24 to be woven in the loom, it is possible to form several corners 30: there are then as many sleeves 62 as there are angles 30. This technique ensures continuity son while ensuring a high directivity to weaving and minimizing friction between the son.

In parallel with the weaving of the wedge 30, it is advantageous to carry out an offset of the woven face 32 in a direction comprising a component Z normal to the X, Y plane of the plies. For example, a lowering of the woven surface 32 with respect to plies 24A, 24B makes it possible to place the pick 34 forming an angle 30 above this surface 32, and to form a three-dimensional part comprising a first wall 32 and two blanks of walls, that is to say a corner. The device then makes it possible to weave a fold of trihedral angle shape directly according to the desired three-dimensional profile, for example according to the figure 2 , with continuity of the son between the faces 12, 14, 16 and at the edges 10z.

For this purpose, the loom 20 then comprises means 66 allowing this shift. In particular, the weaving is performed on son stretched in a frame 22, which remains fixed, but which comprises a mobile shaping frame 66 which shifts the woven preform by resting on the first face 32 to provide training corner 30, the tension of the fabric and the "marking" of the edges. The movable frame 66 preferably corresponds to the surface of the first woven face 32, but it could be limited to an area adjacent to the edges of this face, or even to the only edges along which the secondary weft thread 34 passes. The frame 66 lowers the fabric as the weaving in the Z direction is advanced, to obtain an optimized placement of the yarns 34 working in the Z direction during weaving.

1. 1. Dans un premier temps, tel que présenté plus haut et illustré en figure 3, il y a formation de la première nappe 24A, tissage de la première face 32 parallèlement au rentrage de la deuxième nappe 24B. La duite 28 peut être insérée par le premier système à lance 64A ou manuellement ; la duite 28 peut être continue avec les fils de chaîne ou non.
2. 2. La foule 56A de la première nappe 24A s'ouvre : figure 5A.
3. 3. La première lance 64A, tenant à son extrémité la bobine 60 de fil de trame secondaire 34, s'insère dans la foule 56A ; il est possible que le fil de trame secondaire 34 soit unitaire avec le fil de trame primaire 28. Une fois la foule traversée, la lance 64A insère la bobine 60 dans le premier fourreau 62 et la relâche après que le fourreau 62 a bloqué la bobine 60 : figure 5B.
4. 4. La première lance 64A ressort de la foule 56A qui se referme. Pendant ce temps, le fourreau 62 fait une rotation en direction de la seconde lance 64B, et la seconde série de cadres ouvre une foule 56B dans la deuxième nappe 24B : figure 5C.
5. 5. La seconde lance 64B vient s'insérer dans la deuxième foule 52B pour venir chercher la bobine 60 qui s'y fixe : figure 5D.
6. 6. Le fourreau 62 lâche la bobine 60 puis la lance 64B ressort de la foule 56B avec la bobine 60 ; la foule 56B peut se fermer et la nappe 24B se reformer. Il y a alors tassage de la duite 34 insérée sur chacun des côtés de la face 32 tissée, un angle 30 étant formé : figure 5E.
7. 7. Pour la réalisation d'un coin tridimensionnel, il y a poussée par le cadre mobile 66 pour décaler verticalement la première face 32 : figure 5F.
8. 8. Le procédé se répète ensuite, avec ouverture d'une foule 56B' dans la deuxième nappe 24B, insertion de la deuxième lance 64B pour déposer la bobine 60 dans le fourreau et retrait de cette lance pour que le fourreau 62 soit tourné vers la première lance 64A : figure 5G ; et ainsi de suite.

As illustrated in figures 5 weaving by a loom according to the invention is preferably carried out as follows:

1. 1. As a first step, as presented above and illustrated in figure 3 there is formation of the first ply 24A, weaving of the first face 32 parallel to the tapping of the second sheet 24B. The pick 28 may be inserted by the first lance system 64A or manually; the pick 28 may be continuous with the warp threads or not.
2. 2. The crowd 56A of the first sheet 24A opens: Figure 5A .
3. 3. The first lance 64A, holding at its end the coil 60 of secondary weft wire 34, is inserted in the crowd 56A; it is possible for the secondary weft thread 34 to be unitary with the primary weft thread 28. Once the shed is passed through, the spear 64A inserts the spool 60 into the first sleeve 62 and releases it after the sleeve 62 has blocked the spool 60: Figure 5B .
4. 4. The first lance 64A springs from the crowd 56A which closes. Meanwhile, the sleeve 62 rotates toward the second lance 64B, and the second series of frames opens a crowd 56B in the second web 24B: Figure 5C .
5. 5. The second lance 64B is inserted in the second crowd 52B to pick the coil 60 which is fixed there: figure 5D .
6. 6. The sleeve 62 releases the coil 60 and the lance 64B springs from the crowd 56B with the coil 60; the crowd 56B can close and the sheet 24B to reform. There is then tamping of the pick 34 inserted on each side of the woven face 32, an angle being formed: figure 5E .
7. 7. For the realization of a three-dimensional corner, there is pushing by the moving frame 66 to vertically shift the first face 32: figure 5F .
8. 8. The process is then repeated, with opening of a crowd 56B 'in the second web 24B, insertion of the second lance 64B to deposit the coil 60 in the sleeve and removal of the lance so that the sleeve 62 is turned towards the first spear 64A: figure 5G ; And so on.

The secondary weft yarns 34 are thus non-rectilinearly inserted along the directions along X and then along Y, allowing fabrication of the orthogonal faces; the reserves of X and Y son combined with collective voltage regulation systems provide the material for the constitution of these faces.

It is preferable that the tamping comb of each secondary pick 34 is unitary for the different faces, so as to proceed once the entire angle is achieved. Thus, the parallel orientation of the weft threads 34 with respect to the first face 32 is optimized.

This gives a corner 70, illustrated in figure 5H , whose wire 72 can be continuous, thanks to a non-rectilinear insertion and a tuck in open frames 22A, 22B during the weaving phase. This is particularly advantageous because the existing three-dimensional machines manufacture only "volume" (cubic, cylindrical) or profiled (T, H, E, ...) shapes: here, it is a matter of producing a three-dimensional walled form 70 dimensional. In addition, this system meets the needs in terms of Continuity of wire 72. Moreover, the movement along the Z axis makes it possible to match the shapes of the three-dimensional fold 10, which greatly facilitates its manufacture during its weaving phase.

In particular, the device is adapted to the realization of trunk corners according to the figure 2 , in which the dimensions of the part 10 are of the order of 400 mm × 220 mm × 200 mm, or even 800 × 220 × 200 mm ³ . The carbon wire used advantageously comprises between 6000 and 24000 filaments, preferably 12000. The ideal weight per unit area of each fold is 200 g / m ² to 1200 g / m ² , preferably 600 g / m ² . A trihedral angle 70 thus produced allows the formation of a trunk corner 10 after impregnation of a resin. Advantageously, the volume ratio of the fibers within the total volume of the finished part is 55 to 60%. The preform may preferably be superimposed on other preforms of the same nature, advantageously with an angulation between their son, so as to optimize the resistance of the final part 10 vis-à-vis the directions of mechanical stresses in the composite part.

Although described with a trirectangle trihedral angle 70, other possibilities are conceivable. In particular, it is possible to shift the first face 32 obliquely, to form non-orthogonal faces between them. It is also possible not to weave at right angles on the first face 32.

It is also possible to realize a structure with several corners, resulting in particular from a hexahedron and comprising four or five faces. In this case, the preceding steps 5 and 6 are repeated as many times as at angles 30 (thus of sleeves 62) until the reel reaches the last spear or until it has made a turn complete, where step 7 is then engaged. If a complete turn (four passes passed around the face 32) has been made, it is possible either to recover the coil 60 by the first spear 64A, so that the shuttle 60 keeps rotating, from a lance to the next one is, like a "classical" arrival at the last spear, to make the reverse run to the spool: the spool is transmitted from sheath to sheath by the lances to its initial position.

The loom according to the invention is therefore particularly suitable for weaving reinforcements of composite structures, in view of optimizations allowing a smaller space while allowing the weaving of son forming angles, possibly in three dimensions. However, other applications are conceivable, and in particular, each of the elements making up the loom according to the invention can be used independently of one another.

Claims (15)

1. A weaving loom (20) used for the weaving of a fabric (70) in the weft of which at least one thread (34) forms a angle (30), with the loom structure forming a frame (22) with four sides that include:

   - first means of drawing-in of threads on the first side (22A) to form a first strip (24A) between the first and the third sides (22A, 22C),

   - second means for the drawing-in of threads on the second side (22B) to form a second strip (24B) between the second side (22B) and a fourth edge, composed of open hooks (26B) around which the threads (28) can form a loop,

   - a first weaving-shed formation system on the first strip (24A) at the level of the first side (22A),

   - a second weaving-shed formation system (40) on the second strip (24B) at the level of the second side (22B), including open elements (26B) for manipulating the threads (28),

   - a spool (60) used to contain a winding of weft thread (34) intended to weave the strips,

   - a receptacle (62) located between the first and second sides (22A, 22B), and the first and second strips (24A, 24B), used to hold the spool (60),

   - a first and a second pick-tamping comb traversing the first and second strips (24A, 24B).
2. A loom according to claim 1, in which the elements for manipulating the threads of the second weaving-shed formation system (40) are drawing-in hooks (26B) extended by operating rods (42), with each rod (42) pivoting about an axle (46).
3. A loom according to claim 2, in which the second weaving-shed formation system (40) includes means (50) for putting selective pressure on the rods (42), stitching between a rest position and an operating position so that, in the operating position, certain drawing-in hooks (26') are offset in relation to the others, perpendicularly to the strip (24B).
4. A loom according to claim 3, in which the means for putting selective pressure (50) tilt about the same axle (46) as the operating rods (42) and include an initialisation axle (52) that is able to exert a thrust on all the rods (42) in order to align them, and selection means (54, 58) that are able to exert an opposite pressure on certain rods (42) to form the weaving shed (56).
5. A loom according to one of claims 1 to 4, in which the first drawing-in system is composed of open hooks (26A) around which the threads can form a loop.
6. A loom according to claim 5, in which the first weaving-shed formation system is of a similar nature to the second weaving-shed formation system (40).
7. A loom according to one of claims 1 to 6, in which the drawing-in hooks (26) are associated with tensioning means (36, 38).
8. A loom according to one of claims 1 to 7, including first and second means (64) to move the spool (60) across the first and second strips (24A, 24B) along first and second directions, and to place it into the sheath (62).
9. A loom according to claim 8, in which the sheath (62) includes an opening for reception of the spool (60), and rotates between two positions in which the opening is directed along the first and the second directions respectively.
10. A loom according to claim 9, in which the spool (60) includes an appendage of pointed shape, and the sheath (62) includes, on its face opposite to the reception opening, an orifice complementary to the appendage so as to guide the spool (60) during its insertion.
11. A loom according to one of claims 8 to 10, in which the means to move the spool (60) include first and second rapiers (64A, 64B) that can be attached to the spool (60) in a removable manner, and the sheath (62) includes means so that it is able to hold the spool (60), in a removable manner.
12. A loom according to one of claims 1 to 11, which also includes means (66) to move a woven part (32) of the first strip (24A) in a direction (Z) orthogonal to the strips (24A, 24B).
13. A loom according to one of claims 1 to 12 in which the first and second combs are attached to each other.
14. A loom according to one of claims 1 to 13, that also includes third drawing-in hooks (26) on the side (22D) opposite to the second side (22B), to form the fourth edge.
15. A loom according to one of claims 1 to 14, that includes a second sheath (62) opposite to the first, in relation to one of the first and second strips (24A, 24B), and a third rapier (64) for insertion of the spool (60) and pointing toward the second sheath (62).

Images