FR2568171A1 - Process for the production of a sheet consisting of yarns formed from strong filaments, application to the production of tubular elements and tubular elements obtained thereby - Google Patents

Abstract

Process for the production of a sheet consisting of filaments 4 formed from strong yarns such as glass fibres, carbon fibres, boron fibres or the like, and bonded to each other by a curable synthetic resin 7. According to the invention, this process is characterised in that at least one continuous yarn 4 is applied to a support 1, which yarn is coated with the said resin 7, making it follow a pattern including a plurality of elongate portions 9 close to each other and at least substantially parallel to each other and in that the said pattern is subjected to a pressure at least approximately orthogonal to the said support. Production of tubes of synthetic fibres coated with curable synthetic resin.

Description

The present invention relates to a process for producing a sheet made up of threads formed from resistant filaments, such as glass, carbon, boron fibers or the like, and bonded together by a curable synthetic resin. It also relates to a method for producing a tubular element by means of such a sheet of resistant fibers, as well as to the tubular element obtained by the implementation of this latter method.

It is known that there are currently two methods for producing a tubular element made of resistant fibers coated with polymerizable synthetic resin. Such elements are for example intended for the production of fishing rods, masts, poles, etc.

The first known technique consists in winding on a mandrel whose external surface corresponds to the internal surface of the tubular element to be obtained, a multitude of filaments coming from as many coils which are unwound. Some of these filaments are wound helically on the mandrel, while others are arranged longitudinally relative to the latter. Such a known method is difficult to implement because of the large number of coils unwinding simultaneously. In addition, this method is more suitable for mass production of great lengths than for the manufacture of products which must have particularities. In particular, with the implementation of this process, it is difficult to carry out reinforcements, extra thicknesses, etc.

The other known technique consists in starting from a fabric of resistant fibers impregnated with thermosetting resin and in winding up to polymerize this fabric on a mandrel.

However, this second technique also raises difficulties. Indeed, it is necessary to carry out a number of complete turns of the mandrel with the fabric, so that one may have to put more fabric than the characteristics of the finished product would require.

Furthermore, the weight of the different fabrics varies by step, so that it is not possible to apply the quantity of material just necessary to the mandrel.

Finally, the fabrics pre-impregnated with synthetic resin come in standard sizes, which leads to losses during cutting and preparation ~ of the form of fabric to be wound on the mandrel.

The object of the present invention is to remedy the drawbacks of the two known methods, mentioned above, and to make it possible to use, for the production of a tubular element, just the right amount of basic material, c '' is to say resistant fibers coated with synthetic resin.

To this end, according to the invention, the process for producing a sheet made up of threads formed from resistant filaments, such as glass fibers, carbon fibers, boron fibers or the like, and linked together by a synthetic resin curable, is remarkable in that one applies to a support at least one continuous wire coated with said resin by making it follow a pattern comprising a plurality of elongated portions close to each other and substantially parallel to each other and in that subjects said pattern to a directional pressure at least approximately orthogonal to said support.

Thus, according to the invention, a sheet is obtained in which elongated portions of son are mutually parallel and are linked by the synthetic resin due to the pressure exerted on said pattern. It can therefore be seen that, according to the invention, it is possible to simply produce a sheet of fibers of the desired size, not requiring any drops during winding on the mandrel.

The density, that is to say the distance separating elongated portions of wires, can be adjusted to the characteristics desired for the tubular element to be produced.

In particular in order to obtain the desired high densities, it is possible to apply to said support several superposed layers of at least one continuous wire coated with resin, each layer consisting of a pattern comprising a plurality of elongated portions at least substantially parallel and said elongated portions of a pattern of one layer being parallel to the corresponding elongated portions of the patterns of the other layers. Thus, by the multiplication of layers, high densities can be obtained in a single winding around the mandrel, and without loss.

Preferably, in the case of a sheet comprising several superimposed layers, it is advantageous that an elongated portion of yarns of a layer is located between two elongated portions of yarns of an adjacent layer.

To implement the method according to the invention, it is possible to choose a support in the form of a plate on which a pattern resembling a Greek very elongated in one direction is produced with the wire. For example, the support plate is fixed and has pins at its opposite ends around which is wound said wire. Optionally, after application of the pressure, the ends of the ply are cut to eliminate the portions of transverse son connecting said elongated portions.

However, in an advantageous embodiment, said support is rotatable and said portions of elongated wires are constituted by turns of wires winding on said support. To obtain the sheet, it suffices to cut the winding obtained parallel to the axis of rotation of said support. Such a support can for example be a drum.

However, to avoid any possible natural rolling of the sheet, it is advantageous for the support to be constituted by a plate mounted to rotate around an axis of its plane.

The implementation of such a support therefore makes it possible to obtain either a ply whose length is twice the length of the plate after cutting at one end, or two plies each of which has the length of the plate, after a cut at each end of it.

It is thus seen that thanks to the invention, it is possible to produce a sheet of resistant fibers precisely adapted to the element which one wishes to produce.

 Also, according to another aspect of the present invention, the process for producing a tubular element by means of a sheet of resistant fibers coated with hardenable resin, by winding said sheet around a mandrel, then hardening of said resin, is remarkable in that lton realizes said sheet according to the method described above.

Preferably, during the production of this tubular element, resistant fibers are wound helically on the mandrel, before winding of said ply thereon.

Resistant fibers can also be wound helically on said sheet, after winding of the latter on the mandrel.

There are thus obtained, according to the invention, tubular elements which include the quantity and quality of material just adapted to the characteristics and properties which they must have.

The figures of the appended drawing will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

Figure 1 is a schematic perspective view illustrating an embodiment of the method according to the invention.

Figure 2 is an enlarged cross section of the support of Figure 1, carrying turns of resistant fibers.

FIG. 3 illustrates, in schematic perspective, the start of the production of a tubular element according to the invention.

FIG. 4 illustrates the end of the production of the tubular element of FIG. 3.

The embodiment of the method according to the invention, shown in FIG. 1, implements a support plate 1 which can rotate around a median axis X-X passing through its plane, under the action of means not shown. This support plate 1 has for example a rectangular shape and is provided with lateral edges 2 and 3 parallel to the axis X-X. For reasons of fiber tension, it may be advantageous for the support plate 1 to be thicker in line with the axis X-X than in the vicinity of its edges 2 and 3.

On the support 1 is wound a wire 4 coming from a single coil 5. If the wire of the coil 5, which consists of resistant filaments, is not originally impregnated with a thermosetting synthetic resin, the wire 4 passes into a tank 6 containing such a resin 7, so that at its exit from tank 6, the wire is coated with resin.

The wire also passes through a walkman 8 capable of back and forth movements parallel to the axis X-X.

It is thus understood that when the support 1 rotates around its axis X-X and that the player 8 moves, wire 4 is unwound from the coil 5 and comes to be wound on the support 1 by forming turns 9.

As can be seen in Figure 2, which shows a longitudinal section of the support 1 provided with wire winding 4, it can be arranged in several superimposed layers, so that the wire of a layer is between two yarn from an adjacent layer
When, as mentioned above, a predetermined number of turns is obtained, the rotation of the support 1 can be stopped and the turns 9 can be cut, for example along a line xx passing through the edge 3, to obtain a sheet composed of straight elongated parts of son 4 embedded in a synthetic resin 7. For this, it suffices to align the parts of the turns 9 located on either side of the support 1.

Before or after cutting the turns 9, the wire windings are subjected to calendering in order to give the sheet a determined thickness and to ensure the connection between the wires by the resin.

To manufacture a tubular element according to the invention, from such a ply 10 (see FIG. 3), it suffices to roll the ply 10, obtained by cutting along the line xx of the winding of the turns 9 on a mandrel adequate 11. At this time, the open and aligned turns 9 are parallel to the axis YY of the mandrel 11.

Before winding of the sheet 10 on the mandrel 11, the latter can be coated with helical windings 12 (shown diagrammatically in FIG. 3) of fibers impregnated with resin, for example so as to give the tubular element a obtain its resistance to crushing.

 In addition, the helical winding 12 facilitates demolding of the element of the mandrel 11.

After winding of the ply 10 on the mandrel 11, it is also possible to wind on said ply 10, additional external helical windings 13 (shown diagrammatically in FIG. 4) of fibers impregnated with resin, to also participate in the compressive strength of the tube.

Then, the sheet 10 and the helical windings of synthetic fibers impregnated with resin 12 and 13 are polymerized to obtain the tubular element sought.

Finally, the assembly 10, 12, 13 is removed from the mandrel 11 and then finished to give the tubular element sought.

Claims (10)

1 - Method for producing a sheet made up of threads (4) formed from resistant filaments such as glass fibers, carbon fibers, boron fibers or the like, and bonded together by a curable synthetic resin (7), characterized in that at least one continuous wire (4) coated with said resin (7) is applied to a support (1) by making it follow a pattern comprising a plurality of elongated portions (9) close to each other and at least substantially parallel to each other and in that said pattern is subjected to a pressure at least approximately orthogonal to said support. 2 - Process according to claim 1, characterized in that several superimposed layers of at least one continuous wire (4) coated with resin (7) are applied to said support (1), each layer consisting of a pattern comprising a plurality of elongated portions at least substantially parallel and said elongated portions of a pattern of one layer being parallel to the corresponding elongated portions of the patterns of the other layers. 3 - Method according to claim 2, characterized in that an elongated portion of wire of a layer is located between two elongated portions of wire of an adjacent layer. 4 - Method according to one of claims 1 to 3, characterized in that said support is a plate, on which said wire draws an elongated Greek. 5 - Method according to one of claims 1 to 3, characterized in that said support (1) is rotatable and in that said elongated portions are constituted by turns (9) of son winding on said support. 6 - Method according to one of claims 1 to 3, characterized in that said support is a plate (1) rotatably mounted about an axis X-X of its plane. 7 - Method for producing a tubular element by means of a sheet of resistant fibers coated with hardenable resin, by winding said sheet (10) around a mandrel (11), then hardening of said resin, characterized in what said ply is made according to the method of any one of claims 1 to 6.  8 - A method according to claim 7, characterized in that the resistant helical fibers (12) are wound on the mandrel before winding of said ply on. this one. 9 - Method according to one of claims 7 or 8, characterized in that the resistant fibers are wound in a helix (13) on the web, after winding thereof on the mandrel. 10 - Tubular element and in particular pS * e rod element, obtained by implementing the method of any one of claims 7 to 9.