EP0101351B1 - Process and machine for making a complex fabric by multidirectional weaving - Google Patents

Description

The present invention relates to a method and to a machine for producing a woven piece formed from threads assembled by multidirectional weaving and capable of serving as a reinforcement in the manufacture of a body of composite material.

Such reinforcements are used after impregnation with an appropriate binder, to obtain parts capable of withstanding very high mechanical and thermal stresses, such as nozzles, structural parts of the satellite, reentry bodies or rotor hubs. rotorcraft.

There is known from American Patent No. 4,218,276 (AVCO) a manual process for producing three-dimensional structures, consisting in arranging vertically and parallel needles at the top, held apart by two combs arranged at right angles. A layer of fabric is then placed on the tips of the needles, on which a plate pierced with holes corresponding to the needles rests, the tips of which penetrate the layer of fabric pushed down by the plate. The operation is repeated with circulation of the combs, until the thickness required for the stack is obtained, which is then removed from the machine. Then filamentary reinforcements are introduced into the holes in the stack to form a three-dimensional structure. To implement this process, it is therefore necessary to have layers of fabric previously produced and cut to the desired dimensions for each specific product. In addition, if this patent proposes the production of so-called three-dimensional structures in which rigid elements such as metal needles are arranged vertically, it can be seen that these structures are not obtained by simultaneous weaving of threads on these needles. Indeed, we first make cloth layers, then we stack them and we plug them on said needles.

By French patent 77/18831 in the name of the plaintiff, there is also known a three-dimensional weaving process and machine for the production of woven armatures of hollow revolution. In a network of rods, kept parallel to the generatrices of the body to be produced by means of grids, are introduced and woven in a fixed plane, on the one hand, circumferential threads by unwinding in concentric circles a sheet of parallel threads and on the other hand, radial threads by knitting using a needle of a thread in the form of a chain. In this process, the rods can be metal rods which, at the end of weaving, are driven out and replaced, by means of a lacing arrangement, by threads which ensure the longitudinal filling.

The process known from American Patent No. 3,955,602 makes it possible to produce parts of simple geometric shape such as essentially parallelepipedic blocks in which the wires arranged in the same plane open out on either side of a network of rods vertical with protrusion and therefore require the use of a thread locking means.

In general, the methods of the prior art require specific tools for the part to be produced insofar as the weaving is linked to the spacing or pitch of the vertical rods. They therefore do not allow rapid and economical changes in the definition of woven parts.

Furthermore, most of the known methods for producing three-dimensional woven structures require the placement of a large quantity of spools of threads and therefore their manipulation in order to move from one piece to another.

Finally, the essential problem to be solved in the weaving of structures of the kind considered lies in the fact that the threads to be introduced into a network of rods or rods must be deposited in such a way that there is no residual tension in them.

Indeed, the accumulated tensions would end up deforming the network and would prevent weaving from continuing, for example by blocking the machine used. This problem is usually solved either empirically, by the skill of the operator, or by using a tool for holding the rods with the wires under tension and the threading of each wire in a needle.

The present invention overcomes the drawbacks of the methods and apparatus of the prior art; its subject is a process which consists, in an initial weaving phase, of establishing a network of rigid, parallel and non-contiguous rods, of depositing at one end of this stationary network, a single thread following a winding path zigzagging between the end parts of said rods, this wire forming successive layers superimposed in planes transverse to the direction of the rods, compacting these layers of wire as they are formed, this compaction being accompanied by a sliding of said layers along the sticks, then if necessary replace the beguettes with threads in a final lacing phase.

The compaction with sliding of the layers of wire along the rods is preferably carried out by discontinuous application of a pressure on each new layer completed, all of the superimposed layers being supported at its base by a support surface which s away from a continuous movement of the deposit area of the weaving thread in order to give place to the new layers of thread to be deposited.

The wire should be deposited without tension in the network of rods, being for this purpose delivered with mechanical thrust on demand in a direction parallel to that of the ba lookouts.

The wire can be deposited in meanders oriented in the superimposed layers alternately in one direction, then in another direction crossed with respect to the previous one, for example perpendicular (in this case, these two directions form with that of the rods a triangular trihedron).

Thus, the method according to the invention makes it possible to weave three-dimensional profiled pieces of complex shapes and of any size, by depositing in the free spaces a network of rods defining a direction of the piece to be produced, a wire in any direction orthogonal to the previous one. This wire comes from a single coil and is mechanically unwound from the top of the rods (supposed to be arranged vertically), at their upper part and parallel to their direction. When a layer of yarn is deposited, it is compacted at the same time as the member intended to support the part being woven is shifted to allow the deposition of the next layer.

When the directions perpendicular to the rods have been materialized by the thread according to this weaving mode, these rods are driven out and replaced by a thread, preferably according to the method described in French patent application No. 80/17666 in the name of the applicant .

It is also possible to use rods made of a material remaining in the part after weaving, such as for example pultruded rods.

Thanks to this process, it is possible to modify at will, in each layer, the direction of the thread, deposited by the top of the rods, according to the stresses to which the woven piece is likely to be subjected. This is not the case in known methods, where precisely the direction of the wire is generally imposed by the terms of the method used.

In addition, the method of the invention makes it possible to eliminate any system for stopping the threads introduced perpendicularly to the network of rods and therefore leads to the production of a very simple weaving machine.

Finally, the arrangement of a single reel facilitates the monitoring of the unwinding of the wire. In the prior art, it is generally necessary to provide numerous bobbins to supply the needles making it possible to weave the threads of the same layer, these bobbins being equipped with devices for unwinding the threads and for tensioning, or even braking, in order to make arrive the same amount of wire from each of the coils for the realization of a layer and this, without tension, so as not to deform the network of rods or rigid rods. The method according to the invention overcomes these constraints.

The invention also relates to a machine for implementing the method defined above. This machine comprises, arranged one above the other in a fixed frame, a set of three non-rotating horizontal frames, but movable vertically independently, among which the intermediate frame carries a set of horizontal plates provided with perforations ordered in a regular grid and intended to receive rigid rods of equal length which are thus maintained in a regular vertical network, the upper frame carries, by means of a movement mechanism in two crossed horizontal directions, preferably perpendicular, a shuttle which is thus movable in all directions in a horizontal plane situated slightly above the top of the network of rods and is capable of depositing there above a weaving thread along a winding path, and the lower frame carries a horizontal non-perforated stop plate, underlying the network of rods. It may be useful for the machine to also perform a terminal lacing phase; in this case, it should further comprise a lacing arrangement making it possible to replace, after completion of the weaving, the rods with threads. This lacing arrangement preferably comprises an upper device for actuating a lacing needle and a lower device for introducing a lacing wire, these devices being carried by respective displacement mechanisms in two crossed horizontal directions, mounted respectively on the upper frame and on the intermediate frame.

Advantageously, the shuttle of the machine comprises means for driving and pushing the wire capable of ensuring the delivery of the latter without tension and constituted by two rollers between which the wire is pinched and one of which is actuated in rotation by a motor, these rollers pushing said wire, when it is deposited, in a vertical wire guide tube.

Furthermore, the machine preferably comprises a horizontal perforated plate capable of descending on the network of rods, the ends of the latter then penetrating into its perforations, packing the layers of wire woven into said network. This perforated tray can be carried by the upper frame above the shuttle, which is removed from time to time from the network of rods to allow the descent of said perforated tray on the woven mass.

Below the network of rods, the stop plate can be constituted by a disc driven in rotation around its vertical axis and comprising a vibrating bar ensuring by scanning the longitudinal maintenance of the rods at a constant height on average despite the action drive down that they undergo from the woven mass during its manufacture.

It is advisable to associate with a machine according to the invention a digital control device controlling and synchronizing according to a pre-established program all the movements of its mobile members, in particular those of its shuttle which define the configuration of the winding paths of deposition of the wire forming the successive layers of the woven mass.

• La figure 1 représente schématiquement, en élévation, une machine de tissage multidimensionnel selon l'invention, la moitié de gauche correspond à la phase de tissage et la moitié de droite à la phase de laçage.
• La figure 2 représente en perspective une vue de dessus du réseau de baguettes et de la masse tissée confectionnée dans celui-ci, ainsi que la navette et son mécanisme de déplacement.
• La figure 3 représente à plus grande échelle le détail lll de la figure 1.
• La figure 4 représente une coupe suivant la ligne IV-IV de l'objet de la figure 3.
• La figure 5 représente schématiquement une coupe suivant la ligne V-V de l'objet de la figure 4, montrant en même temps le plateau perforé inférieur qui supporte la masse tissée et le plateau perforé supérieur, descendu en position de tassement de cette dernière.

The following description, with reference to the accompanying drawings by way of nonlimiting examples, will make it possible to understand clearly how the present invention can be put into practice.

• Figure 1 shows schematically, in elevation, a multidimensional weaving machine according to the invention, the left half corresponds to the weaving phase and the right half to the lacing phase.
• Figure 2 shows in perspective a top view of the network of rods and the woven mass made therein, as well as the shuttle and its movement mechanism.
• FIG. 3 represents the detail III of FIG. 1 on a larger scale.
• FIG. 4 represents a section along line IV-IV of the object of FIG. 3.
• FIG. 5 schematically represents a section along the line VV of the object of FIG. 4, showing at the same time the lower perforated plate which supports the woven mass and the upper perforated plate, lowered into the compacting position of the latter.

In these drawings, it should not be attached to the fact that the number of rods of the network is variable from one figure to another. This is so for the simple reason of convenience of representation. In practice, the number and the arrangement of the rods are chosen according to the conformation and the dimensions of each woven piece to be produced.

The machine represented in FIG. 1 comprises a frame 1 in which are arranged, between its base 1a and its roof 1b, several fixed vertical threaded rods 2 (at least three) along which three horizontal frames 3, 4, 5 can move. . To this end, each of these frames is provided with a particular motor (not shown) which can drive in rotation, via a chain 6, nuts 6a engaged on said threaded rods (only one of the nuts 6a of the only frame 4 has been shown, with a part of the corresponding chain 6). Each frame can thus be animated at will with an upward or downward movement by command of said motor.

The upper frame 3 carries a perforated plate 7 and, by means of a movement mechanism 8 with crossed movements, a shuttle 9 ensuring the deposition of a wire 10 in a network 14 of rigid metal rods 11, held vertically along a regular distribution by perforated plates 12, 13 (the number of plates 13 depending on the height of the part to be produced) carried by the intermediate frame 4. The perforations of the plates 7, 12 and 13 are arranged in a grid (straight, as in this example, or oblique), so that the rods 11 of the network 14 which pass through them cause corridors to cross each other at an angle, here a right angle, in which will be deposited alternately in meanders of directions perpendicular to wire 10 by shuttle 9.

The mechanism 8 ensuring the movements of the shuttle 9 comprises a horizontal strip 15 along which the shuttle can move under the action of a motor 16 by means of a drive belt located inside the strip (Figure 2). The latter is itself movable in the perpendicular horizontal direction, its ends rolling on guide rails 17, 18 fixed to the frame 3, under the action of drive belts 19, 20 driven by a motor 21 also integral with the frame 3. The shuttle 9 can thus move in two perpendicular horizontal directions 22, 23, therefore be brought successively to any point on the horizontal plane limited by the rails 17, 18.

The shuttle 9 is constituted (FIG. 3) by a carriage 24 sliding along the strip 15 and carrying a small stepping motor 25 and two rollers 26, 27 between which the wire 10 is pinched. The caster 26 is driven in rotation by the motor 25, while the caster 27 is mounted idle. By controlling the motor 25, the wire 10 is pushed more or less quickly into a vertical wire guide tube 28 fixed to the plate 24 and passing between the upper ends of the rods 11 of the network 14 to deposit the top of this network. wire following the chosen winding path.

To weave a piece of determined shape on the machine described, we first engage the rods 11 through the perforated plates 12, 13 to arrange them in a regular network 14 offering the desired shape (in this case , it is a cylindrical shape of circular or polygonal section). The frame 3 being placed at a height such that the wire guide tube 28 of the shuttle 9 penetrates into the upper region of the network 14 (FIG. 3), the shuttle is moved thanks to its mechanism 8 along a sinuous path whose meanders out oriented in one of the directions of the orthogonal corridors of the network 14, parallel to the directions 22, 23 of movement of the shuttle 9. At the same time, the motor 25 of the latter is started, so that the wire 10, coming from a coil 29, is deposited from above the network of rods along this winding path between the upper ends of these (Figure 4). When a layer C of wire has been deposited, the following layer C is deposited in superposition, in the other direction 22 or 23. As soon as each layer is completed, the shuttle 9 is moved aside on the side and controls a downward movement of the frame 3 so as to bring the perforated plate 7 which it carries (FIG. 5) down onto the network 14 in order to compact the woven mass 30 formed by all of the layers C made up. To ensure easy penetration of the rods 11 into the perforations 31 of the plate 7, the ends of the rods are cut into a point and the orifices of the perforations are flared, as shown. At the same time, the frame 4 is lowered by an amount substantially equal to the thickness of a layer, so that the woven mass 30 gradually descends ment, supported by the perforated plate 12 secured to the frame 4 and packed by the perforated plate 7 secured to the frame 3. After each compaction operation, where the perforated plate 7 always descends to the same level, it is brought up (by upward movement of the frame 3) up to a level which is also fixed, sufficient to make room for the shuttle 9 between said perforated plate and the ends of the rods 11, which then returns to this space to deposit a new layer of wire after having absorbed the slack required by its gap on the side before compaction.

The downward sliding of the woven mass 30 causes the rods 11 to descend. To compensate for this effect, under the network of rods is provided, carried by the frame 5 (of adjustable height), a rotating disc 32 provided with a vibrating bar. 33 (FIG. 1) arranged diametrically on a pair of vibrators with vertical action which causes, by sweeping, an ascent of the rods 11 struck by said bar, the latter thus maintaining an invariable mean position in the direction of the height during the entire course weaving of the piece. At the end of weaving, the frame 4 is located near the frame 5, the perforated plates 13, suspended by chains 34 from the frame 4, having come to be juxtaposed accordingly.

The desired piece being woven, it is then a question of replacing the rods 11 with threads of the same kind as the thread 10 constituting the superimposed transverse layers. To this end, the machine is equipped with an arrangement 35 called "lacing", composed of an upper device 35a and a lower device 35b (shown diagrammatically on the right-hand side of FIG. 1). The upper device 35a is carried by the frame 3 by means of a movement mechanism 36a in two orthogonal directions, similar to the mechanism 8 of the shuttle 9. The same goes for the lower device 35b, including the mechanism displacement 36b is mounted on the frame 3. These lacing assemblies are removable.

In the lacing phase, the frame 3 carrying the piece woven by its perforated plate 12 (the extension 37 provided in the weaving phase being removed) is raised to a height leaving below sufficient space for the descent of the strips 11 a expelled from the woven mass 30. The frame is correlatively reassembled in a position where its perforated plate 7 rests on the top of the woven mass 30. In accordance with the teaching of French patent application No. 80/17666, the upper device 35a lowers a long needle 41 successively vertically above each rod 11, so as to drive it out and cause it to fall at 11a below the frame 4, onto the disc 32 (while it remains held by the perforated trays 13 now assembled and fixed to the top of columns 38). On each descent, said needle hooks into the lower device 35b a wire 39 from a spool 40 and pulls it in a loop through the woven mass 30 to replace the rod it has just chased. Of course, the movement mechanisms 36a and 36b are correlatively controlled in the same way so that the lacing devices 35a and 35b remain constantly facing each other and come successively in line with each rod 11 of the network 14.

The control of the various moving parts of the machine, in particular of the movement mechanisms 8, 36a and 36b (equipped with stepping motors), is carried out in synchronism, in each operating phase, by means of a digital control device in which is introduced a program corresponding to the characteristic of structure, shape and dimensions of the woven piece to be produced.

It is understood that, by the choice of this program, it is possible to obtain the deposition of the wire by the shuttle 9 in each layer along any desired sinuous path between the rods 11 of the network, which can moreover be ordered according to a diagram in cross section. of any shape and geometric arrangement. It is thus possible to obtain woven pieces of cylindrical or prismatic shape, solid or hollow, possibly deformable if the path of the weaving thread is chosen for this purpose in each transverse layer.

Claims (12)

1. Process for the manufacture of a woven article formed of threads assembled by multi-directional weaving and able to serve as an armature in the fabrication of a body of composite material, in which process a network (14) of parallel and unjoined rigid rods (11) is provided in an initial weaving stage, characterised in that the process comprises depositing at a stationary end of the network a single thread (10) following a sinuous path which zig-zags between the end parts of the rods (11), this thread forming successive layers (C) superiomposed in planes transverse to the direction of rods (11) in order to thicken the layers of thread in the course of their formation, this thickening being accompanied by a sliding of the said layers along the rods.

2. Process according to claim 1, characterised in that the thickening with sliding of the layers (C) of the thread (10) along the rods (11) is effected by discontinuous application of pressure on each new layer (C) completed, the assembly of the superimposed layers being supported at their base by a support surface (12) which recedes with a continuous movement from the zone of deposit of the woven thread (10).

3. Process according to claim 1 or 2, characterised in that the thread (10) is deposited without tension in the network of rods (11), the thread being delivered in a direction parallel to that of the rods by mechanical pressure according to demand.

4. Process according to any of claims 1 to 3, characterised in that the thread (10) is deposited in meanders alternately oriented in the superposed layers (C) following one direction and then following another direction with respect to the previous direction.

5. Machine for carrying out the process according to any of claims 1 to 4, characterised in that it comprises, disposed one above the other on a fixed base (1), an assembly of three horizontal and non-rotatable frames (3, 4, 5) which are mobile vertically in an independent manner, the intermediate frame (4) of which carries a set of horizontal plates (12, 13) privided with perforations arranged according to a regular weft and intended to receive the rigid rods (11) of equal length which are thus maintained in a regular vertical network (14), the upper frame (3) of which carries, by means of a displacement ma- chanism (8) operable in two crossed horizontal directions (22, 23), a shuttle (9) which is thus mobile in any direction in a horizontal plane situated slightly above the top of the network (14) of rods (11) and is able to deposit by the upper part a weaving thread (10) following a sinuous path, and the lower frame (5) of which carries, underneath the network of rods (14), a horizontal non- perforated stop plate (32).

6. Machine according to claim 5, characterised in that it further comprises a lacing device (35) permitting replacement of the rods (11) by threads after weaving is completed.

7. Machine according to claim 6, characterised in that the lacing device (35) comprises an upper device (35a) for actuating a lacing needle (41) and a lower device (35b) for the introduction of a lacing thread (39), these devices being carried by respective displacement mechanisms (36a), (36b) operable in two crossed horizontal directions and mounted respectively on the upper frame (3) and on the intermediate frame (4).

8. Machine according to any of claims 5 to 7, characterised in that the shuttle (9) comprises means for entrainment and supply of a thread (10) which are arranged to ensure the delivery of the latter without tension and comprise two rollers (26, 27), between which the thread (10) is pinched and one of which is rotated by a motor (25), these rollers pressing the thread, during its deposit, into a vertical threadguiding tube (28).

9. Machine according to any of claims 5 to 8, characterised in that it comprises a perforated horizontal plate (7) capable of descending on the network (14) of rods (11), the ends of the latter thus penetrating through the perforations (31) and thickening the layers (C) of woven threads in the network.

10. A machine according to claim 9, characterised in that the perforated plate (7) is carried by the upper frame (3) above the shuttle (9).

11. Machine according to any of claims 5 to 10, characterised in that the stop plate (32) is constituted by a disc caused to rotate around its vertical axis and comprising a vibrating pin (33) ensuring by sweeping round the longitudinal maintenance of the rods (11) at a constant average height.

12. Machine according to any one of claims 5 to 11, characterised in that it is associated with a numerically-controlled device for regulating and synchronising according to a predetremined programme all the movements of its movable parts.

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