EP1857579B1 - Method of manufacturing a reinforcement textile article, textile article obtained according to this method, and machine for manufacturing such an article - Google Patents

Description

Technical area

The invention relates to the field of the technical textile industry, and more particularly the manufacture of reinforcing textiles, intended to be integrated in various parts obtained by resin injection or infusion processes. It relates more particularly to a manufacturing process that makes it possible to obtain reinforcing articles that can be integrated in parts of complex geometry and in particular that are not straight.

By way of nonlimiting example, the invention may find an advantageous application for the manufacture of reinforcements used in the manufacture of skis, which have a variable width along their length.

Previous techniques

In general, reinforcing textile articles are intended to impart stiffness properties in the direction of the son of the strongest title that compose them. Indeed, these son typically based on glass filaments, carbon or other, are intended to be impregnated with a resin. After curing, this resin stiffens the reinforcing article within the part in which the injection of the resin took place.

These textile reinforcements can be made in different ways. Thus, one solution is to use a fabric, that is to say with an interweaving of warp and weft threads. The reinforcement may also be based on one or more layers of parallel son superimposed and secured to a support by sewing techniques / knitting. This last type of reinforcement has the advantage that the reinforcing threads are very substantially straight, as opposed to the fabrics in which the embossing generates undulations of the woven threads.

Thus, in order to obtain a reinforcement as flat as possible, the technique of sewing / knitting is particularly appreciated.

To date, when a reinforcing article must be integrated in a piece of complex geometry, typically non-rectangular, it is necessary to make cuts to give this reinforcement the contours of the reinforced part.

It is therefore conceivable that these cutouts, when they are not rectilinear and therefore parallel to the warp and weft threads, can cause fraying of the cords at the edge. Indeed, the son employed are frequently "rovings", that is to say bundles of filaments without torsion, in which each filament is therefore generally free. These fraying problems can be troublesome during reinforcement handling operations, since they generate the detachment of some of the filaments, which can be located in places that are not desired.

Similarly, the free portions of the son that have been cut may tend to slightly detach from the rest of the reinforcement, thus creating disturbances. Indeed, to maintain good deformability of the reinforcement, the son are bonded to the support by binding son which are generally spaced apart. Thus, between two points of successive seams, each wire has a portion exposed to the risk of fraying.

These problems are all the more sensitive that the inclination of the cut is close to the direction of the son, which have a fairly large width and are therefore cut into bevels.

One of the objectives of the invention is therefore to obtain reinforcements having a geometry adapted to the geometry of the parts in which they will be integrated. Another object of the invention is to eliminate the risk of fraying observed during cutting, and in particular cuts close angularly to the direction of the son.

Another objective is the optimization of the mechanical properties of the reinforcement. Indeed, the son that are cut participate only very little in the mechanical reinforcement. These son present on part of the length of the reinforcement therefore increase the weight of the reinforcement, without significantly improving its mechanical properties.

Presentation of the invention

The invention therefore relates to a method of manufacturing a reinforcing textile article. In a conventional manner, this reinforcement comprises in chain a web of threads which is connected to a support by stitching. Conventionally, the warp son are brought opposite the support through a comb whose spacing between the teeth can adjust the density of the warp son in the reinforcement.

According to one characteristic of the invention, the inclination of the comb with respect to the direction of the chain during the advance of the warp threads is varied so as to modify the warp density along the warp. article.

In other words, the invention consists in adapting the spacing between the warp threads by acting on the orientation of the comb they pass through before being sewn on the support. Thus, depending on the orientation of the characteristic comb, the web of warp threads may occupy a greater or lesser width on the support to which it will be bound.

The support can then be cut according to the warp edge warp threads to adapt a non-rectilinear geometry. This cutting takes place advantageously on the machine where the stitching takes place, which makes it possible to eliminate the parts of the support situated outside the zone where the warp threads have been secured. An article is thus obtained which has a width adapted to the part it is intended to reinforce. This reinforcing article thus has warp threads only in the useful parts, and does not comprise zones formed by the support alone.

The warp son constituting the reinforcing portion of the textile article are not cut during this operation and therefore keep all their mechanical properties. The fact of not cutting the reinforcement makes it possible to maintain the integrity of the thread over the entire length of the piece, and therefore to increase the performance of the reinforcing textile article. This makes it possible to take full advantage of the performance of the long fiber reinforcement, in particular on the parts of the geometrically complex piece at the edge, where the yarns are cut at short lengths, in comparison with reinforcements incorporating short fibers for example. This can increase the mechanical performance of the reinforcement for the same weight of fiber, compared to a traditional cutting solution.

In practice, the inclination of the comb may vary between 0 and 80 ° approximately, depending on the width of the desired warp sheet.

In this way, the article obtained has a density of warp threads, that is to say a number of threads per unit length measured transversely, which changes with the characteristic angle given to the comb.

In practice, such a reinforcement can be achieved by integrating supports of very varied nature. Thus, the support may be constituted either by a web, for example non-woven, or a sheet of son arranged in the weft direction of the reinforcement, to confer mechanical reinforcing properties in the transverse direction. It is also possible to use as support a fabric having, for example, yarns of higher strength in the weft direction of the reinforcement, to also confer reinforcement properties in both directions of the final reinforcement. For example, we can use as weft son based on carbon filaments or the like.

The method according to the invention is therefore implemented on a machine which therefore comprises means for varying the inclination of the comb relative to the direction of the warp son. These means can be very varied, and obtained by multiple different mechanisms.

Thus, advantageously in practice, the comb may be rotatable about an axis perpendicular to the web of warp threads passing through it.

In this case, in order to limit the tensions generated by the inclination of the comb, it may be preferable for the axis of rotation of the comb to be situated substantially at its median level.

This process can be repeated several times over the width of the machine to make several textile articles shaped at the same time. In this case, several individual mobile combs can be connected to the same system causing their rotation in a coordinated manner. The method can thus be repeated keeping the axis of rotation of each comb located substantially at each median level, with common actuating means.

The reinforcing textile article obtained can be either cut into the desired length, in order to manufacture pieces in the desired format in both dimensions. It is also possible to produce rolls having one or more successions of reinforcements continuously connected by the shared warp yarns, and having the desired format in the direction transverse to the winding.

Brief description of the figures

• La figure 1 est une vue schématique d'une machine conforme à l'invention montrée en perspective sommaire.
• Les figures 2a et 2b sont des vues de détail illustrant la nappe de fils de chaîne et le peigne caractéristique, respectivement dans deux inclinaisons différentes.
• Les figures 3a et 3b sont des vues de dessus schématiques d'articles de renfort réalisés conformément à l'invention, montrées respectivement dans des configurations où la nappe de fils de chaîne présente occupe des largeurs différentes.

The manner of carrying out the invention, as well as the advantages which result therefrom, will emerge from the description of the embodiment which follows, in support of the appended figures, in which:

• The figure 1 is a schematic view of a machine according to the invention shown in summary perspective.
• The Figures 2a and 2b are detailed views illustrating the warp web and the characteristic comb, respectively in two different inclinations.
• The Figures 3a and 3b are schematic top views of reinforcing articles made in accordance with the invention, respectively shown in configurations where the web of warp son present occupies different widths.

Note that the various elements shown are only for illustration, to better understand the principle of the invention. Thus, the machine and the reinforcements obtained are illustrated with a smaller number of threads than in real applications, and with larger dimensions, solely for the purpose of facilitating understanding of the invention.

Way of realizing the invention

The machine (1) illustrated in figure 1 comprises mainly, in aspects related to the invention, a station (2) for feeding warp son, schematized by a creel (3) supporting a plurality of coils (4) or warp cakes. These warp yarns (5) are fed to an entry station in which they are put in place in the form of a parallel web (7).

After passing through the comb (10) which will be described in more detail below, the warp threads (5) reach, after changing their orientation at the bar (11), the sewing station shown schematically by the block (12). This block (12) corresponds in a conventional manner to the sewing station on machines of the "Malimo" type.

At the sewing station (12), the warp web (7) is secured to a support (15) from the feed station (16).

As already mentioned, this support (15) may be of different natures. It can thus be a veil, typically based on polyester or glass. This support can also be used to confer transverse reinforcement properties, and then comprises glass son or carbon in weft. It can thus be a set of weft threads deposited by a framer, upstream of the seam area (12) or even of a previously made fabric, by weaving weft threads with a weak warp. title, and in particular a coated wire.

The support (15) and the web (7) of warp threads are sewn together with the binding threads (20) which enter the machine through the pierced plate (21). After sewing, the assembly (30) obtained can undergo a garment operation, so as to eliminate the portions (31) of the support (15) located outside the zone (32) where the warp threads have been secured. . More specifically, the machine comprises a station including cutting means (40,41) for cutting the support (15) along the outer chain son. These cutting means are adjustable in width depending on the width of the warp ply.

The operation of the invention is the use of a comb (10) which has a capacity of inclination with respect to the direction of the warp son (7). Thus, as illustrated in figure 2a , all of the warp threads (7) passes through this characteristic comb (10) so as to adjust the distance between the warp threads at the level of the reinforcing article. The spacing between the teeth of this comb (10) thus makes it possible to fix the spacing between the warp threads (8) downstream of the comb (10), or in other words the density of the warp threads, or else their number by unit of width.

This comb (10) can have a capacity of rotation about an axis (13) which passes substantially in the middle of the comb (10), so as to limit the amplitude of the movements of the end zones (17, 18) of the comb (10). 10), and therefore the tension imposed on the warp threads during the movement of the comb.

So, in the configuration illustrated in the figure 2a , the comb (10) is perpendicular to the direction of the warp threads (7), so that the spacing between the warp yarns and downstream of the comb is maximum corresponding therefore to a minimum density of warp yarns on the reinforcement . The width L ₁ of the web (8) of warp threads therefore corresponds here to the maximum value that it will occupy on the reinforcing article.

Conversely, as illustrated in figure 2b when the comb (10) is rotated about its axis (16), the warp threads (8) downstream of the comb are automatically brought closer together. The width L ₂ of the web (8) of warp yarns downstream of the comb (10) is therefore smaller, and globally related to the maximum width L ₁ proportionally to the sine of the angle (α) formed by the comb (10). ) with respect to the direction of advance of the warp threads.

In practice, the inclination of the comb (10) can be modified in real time, as a function of the state of advancement of the reinforcing article, and of the geometrical shape that the string of warp yarns must marry on the reinforcement, itself a function of the geometry of the piece to be reinforced.

After sewing, and as shown in figure 3a , the sheet of warp threads (33) is secured to the support (15) via the binding son (34). We observe at figure 3a that the width of the web of the warp yarns (33) decreases from the top of the figure while moving downwards, insofar as the comb has seen its characteristic inclination modified as and when the the sewing of the warp threads.

This inclination can be accentuated to give the result illustrated in figure 3b . In this case, the warp threads (36) are in an increasingly narrow configuration, so that they release on the support free side regions (31) of warp threads. These areas (31) are then removed by cutting, to retain only the portion of the support located below the warp son sheet (36).

Note that in the densest area, the warp son are the most contiguous, and thus occupy a slightly greater thickness. Likewise, as the number of binding yarns is constant over the entire width, the number of binding yarns passing through the sheet of warp yarns (36) is less than in the less dense zones, as illustrated in FIG. figure 3a .

Multiple embodiments can be made according to the expected mechanical properties, as well as the dimensions of the objects intended to integrate the reinforcements.

Thus, for example, a longitudinal reinforcement used for the manufacture of a ski can be obtained by using glass son of 1,200 tex. In the widest configuration, the warp ply has a width of 126 mm, corresponding to 2.7 threads per centimeter, and a reinforcement density of the order of 329 g / m ² .

The comb is then progressively inclined as the warp threads advance, until an inclination greater than 60 ° is reached. In this configuration, the warp web has a width of about 72 mm, corresponding to 4.7 threads per centimeter and a density at the reinforcement of 564 g / m ² .

The inclination of the comb is then reduced to reach the extremal part of the reinforcement. The comb then reaches an orientation of approximately 35 °, corresponding to a width of the ply of warp threads of 103 mm, that is to say 3.3 threads per centimeter, corresponding to a density at the level of the reinforcement of 396 g / m ² .

The binding yarns employed may be 267 decitex textured polyester yarns sewn on a Malimo 10 gauge machine, i.e. having ten needles per inch, and thus needles separated by about 4 mm. The armor used for sewing is knit weave, generating zigzag stitching zones. Sewing takes place with about 2.5 rows of mesh per centimeter.

Such a reinforcement is therefore usable for producing fabrics having a dimension line corresponding to the width variation of the warp ply.

It follows from the above that the invention has the major advantage of allowing the realization of unidirectional or multidirectional reinforcements, whose Yarns in the warp direction are not rectilinear, but instead are able to fit any geometric shape, thus eliminating the risk of fraying and optimizing the mechanical performance / weight ratio of the reinforcement.

Claims (14)

1. A method for manufacturing a reinforcement textile article, comprising warping a yam layer (7) linked to a support (15) by sewing, wherein the warp yarns (7) are brought in front of the support (15) to be attached thereto by crossing a comb (10) having the space between its teeth enabling to set the density of the warp yarns, characterized in that the slope of the comb (10) is varied with respect to the warp direction as the warp yarns move forward, to modify the warp yam density along the article.
2. The method of claim 1, wherein immediately after the sewing, the portions (31) of the support (15) located outside of the area (32) where the warp yarns have been attached are removed.
3. The method of claim 1, characterized in that the slope of the comb (1) varies between 0 and 80°.
4. A textile article obtained according to the method of claim 1, characterized in that it has a variable warp yam density along its length.
5. The article of claim 4, characterized in that the support (15) is formed of a nonwoven web.
6. The article of claim 4, characterized in that the support is formed of a weft yam layer.
7. The article of claim 4, characterized in that the support is formed of a fabric.
8. The article of claim 7, characterized in that the fabric has yarns of greater linear density in the weft direction of the article.
9. The article of claim 6, characterized in that it comprises a weft of yarns formed from carbon filaments.
10. A machine for manufacturing reinforcement textile articles comprising a feed-in station (6) whereto are conveyed a layer (7) of warp yarns, a support (15), and binding yarns (20), and means (12) for attaching the warp yam layer to said support, by sewing with the binding yarns (20), and comprising a comb (10) crossed by the warp yarns (7) before they are attached to the support (15), characterized in that it also comprises means for varying the slope of the comb (10) with respect to the warp yam direction.
11. The machine of claim 10, characterized in that it comprises cutting means (40, 41) enabling, after sewing, to cut the assembly formed of the support and the warp yarns, to remove the portions (31) of the support (15) located outside of the area (32) where the warp yarns have been attached.
12. The machine of claim 10, characterized in that the comb (10) is rotatable around an axis (13) perpendicular to the warp yam layer (7) which crosses it.
13. The machine of claim 12, characterized in that the rotation axis (16) of the comb is located substantially at its median level.
14. The machine of claim 10, characterized in that it comprises several combs having variable and coordinated slopes.

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