EP0546962A1 - Method for manufacturing a knitted article from metal wires, new type of knitwear obtained this way and its application for manufacturing various composite structures - Google Patents

Abstract

Method for manufacturing a knitted article based on metal wires, which involves making the said structure on a straight tucked-stitch knitting machine, the article produced having a set of the "jersey" type. It is characterised in that the said jersey knitwear is obtained from three elementary threads (1, 2, 3) fed from bobbins arranged on the same side of the knitting machine, the knitting being carried out by stitching the three threads successively, each thread being put on stand-by after the stitching of a row on the opposite side to its feed source. <IMAGE>

Description

The present invention relates to an improved process allowing the production of knitted articles based on metallic threads; it also relates to the new type of articles thus produced.

It has been proposed for a very long time to produce woven or knitted structures from metallic threads, the oldest applications of such articles being, for woven structures, protective mesh, in particular for fencing, and for knitted structures, protective clothing such as mesh dimensions.

Since then, such structures have been used in numerous applications as reinforcing elements, in particular for resin-based articles (laminated articles), and this not only to give such articles improved mechanical characteristics, but also, for certain applications, properties inherent in metallic wires, for example good conduction of electricity. In general, the choice between a woven structure and a knitted structure depends on the envisaged application, the knitted structures having the essential advantage of being able to be easily deformed, which makes them particularly suitable for making articles. molded.

The present invention aims, as said above, to an improvement in the production of such knitted metal structures. To date, to produce knitted structures, use is made, as is apparent in particular from patent US-A-4 242 686, of articles produced on circular knitting looms with picked stitches making it possible to obtain, as is apparent from the figure. 2 of this patent, a tubular structure that is generally cut according to a generator during use.

If circular knitting looms with picked stitches allow very high productivity, such knits have the drawback, however, of having rows of stitches arranged in a helix, which results in a "twisting" phenomenon of the article. Furthermore, when such a tubular knitted fabric is laid flat by cutting it along a generatrix, the edges of the structure lack resistance, they fray given the fact that there is no selvedge. In addition, the "merchant" fold is printed in the metal mesh and has an arcuate appearance.

It would have been possible, to solve the problem of flattening the article, to use as knitting technique looms with straight picked stitches which make it possible, from a single thread, to make knitted fabrics called " jersey "whose structure is illustrated in Figure 1 attached.

In such jersey knitwear and as can be seen from this figure, a single thread F is sufficient to produce the mesh structure, since the loops are formed horizontally by the thread moving either from left to right, or vice versa, so forming rows of intertwined loops one above the other. However, such a knit has a drawback in that it is easy to pull the thread from the -superior part, to bring out the last row of loops of the previous row of stitches and to unravel the article produced. Furthermore, the selvedge L of such a knitted fabric (see right selvedge of the article reproduced in FIG. 1) is such that in this change of direction zone, the thread is bent along a small radius of curvature, which, in the case of the use of metal, can cause shearing and especially produces very deformed edges. In addition, due to the strong tension given to the fabric, it deforms, which leads to obtaining an irregular knitting and a loss of width.

Now we have found, and this is what is the subject of the present invention, that it was possible, using such a knitting technique with picked stitches, implemented on a rectilinear loom, to produce mesh structures from metal wires which overcome all of these drawbacks and lead to perfectly flat structures, and whose selvedges are not only reinforced and limit the risks of enameling, but also are practically perfectly straight.

In general, the invention therefore relates to an improved process making it possible to produce a mesh structure from metal wires, process which consists in producing said structure on a rectilinear loom with picked stitches, the article produced having a type texture. "jersey", the process according to the invention being characterized in that said jersey knit is obtained from three elementary yarns (and not from a single one as in a classic jersey), supplied from bobbins arranged with a same side of the loom, knitting being carried out by successively knitting the three threads, each thread being put on hold after knitting a row on the side opposite to its power source.

Putting on standby after meshing a row on the side opposite to its power source, is obtained by using a guide arranged at the edge, the wire making a retaining loop around said guide. Such a procedure makes it possible to keep the knit in width and, as said above, leads to the production of selvedges which not only are reinforced, but also are practically perfectly straight.

• lorsque le premier fil forme une rangée par exemple de la gauche vers la droite, il est mis en attente à la fin de cette rangée sur la droite de l'article,
• la rangée suivante étant alors produite à partir du second fil qui était mis préalablement en attente sur la droite en allant de la droite vers la gauche,
• la troisième rangée étant réalisée à partir du troisième fil (allant de la gauche vers la droite) étant alors stocké à droite ;
• la quatrième rangée étant réalisée par le premier fil qui était stocké à droite et qui forme la rangée de la droite vers la gauche,
• la cinquième rangée à partir du second fil (sens gauche/droite) ;
• et la sixième rangée à partir du troisième fil qui était stocké à droite (sens droite/gauche).

In other words, in accordance with the invention, the jersey knit is produced from three threads and the weave ratio is six rows, the knitting being carried out so that:

• when the first thread forms a row, for example from left to right, it is put on hold at the end of this row on the right of the article,
• the next row then being produced from the second thread which was previously put on hold on the right going from right to left,
• the third row being made from the third thread (going from left to right) then being stored on the right;
• the fourth row being produced by the first wire which was stored on the right and which forms the row from right to left,
• the fifth row from the second thread (left / right direction);
• and the sixth row from the third wire which was stored on the right (right / left direction).

Thanks to such a procedure, a perfectly flat article is obtained, having stable rectilinear selvages, resistant, impossible to produce with a conventional jersey knitted fabric obtained from a single thread.

Furthermore, thanks to such a method, it has been found that it is possible to work relatively rigid metallic wires, given that said wire forms floats at the edge before being knitted.

Such knitted structures produced in accordance with the invention can be used in numerous applications and in particular to be incorporated into the interior of a resin in order to give it specific properties for producing laminated articles which can be either flat or laid out. shape (by molding for example). Such a knitted fabric can also be used as a reinforcing element or conducting element in association with flat structures (woven textile structures for example, films, etc.) making it possible to obtain various flat complexes usable, for example, as tarpaulins.

• la figure 1 illustre, comme dit précédemment, la strucutre conventionnelle d'un tricot jersey réalisé à partir d'un seul fil alimentaire ;
• la figure 2 illustre un tricot réalisé conformément au procédé selon l'invention.

The invention and the advantages which it brings will however be better understood thanks to the embodiment given below by way of indication but not limitation, and which is illustrated by the appended diagrams in which:

• Figure 1 illustrates, as said above, the conventional structure of a jersey knit made from a single food yarn;
• FIG. 2 illustrates a knitted fabric produced in accordance with the method according to the invention.

Example

An article in accordance with the invention of the type illustrated by FIG. 2 is produced on a straight knitting machine with picked stitches gauge 2 (that is to say comprising two needles per centimeter) double needle bed, one needle needle being used for knit.

Knitting is carried out using three power sources for three identical wires (1,2,3), steel wires having a diameter of 0.25 millimeters. If we consider Figure 2 illustrating the article produced, laid flat, the wire supply sources (1,2,3) are located on the left of the loom.

In addition, three wire distribution systems (grommets) are mounted on the loom and can be successively put into work in synchronism with the carriage making it possible to actuate the needles for forming the meshes. Finally, the loom is equipped in a conventional manner allowing successive implementation of the wire distributors which are put on hold on one or the other of the sides of the loom (right or left) after formation of a row of meshes.

The knitting is carried out, if we refer to Figure 1, by making the first row of stitches with the thread (1), the thread thrower (1) being put on hold on the right side of the loom after realization of its row, the second row of stitches is then made with the thread (2) from the second thrower which was waiting on the right side of the loom and which is brought back on the left side, the third row is made from the wire (3) from the third thrower which was located on the left side and which, after forming the row put on hold on the right side. The next three rows are made successively from the threads (1,2,3) which are brought back to their initial position of departure. By proceeding in this way, we obtain a mesh structure which as a whole is similar to a conventional jersey knit made from a single thread, but the selvedges of the article produced (the right selvedge being represented in Figure 2 ), are such that each thread forms floats on several rows, which not only makes it possible to obtain perfectly straight selvedges, but also promotes the knitting operation.

The mesh structure obtained is therefore in the form of a trellis in which each row of meshes has a height of about eight millimeters and which comprises a column of meshes per centimeter.

Such an article can be used in many applications, for example to be incorporated into the interior of a resin when making a flat or shaped laminated article (molded for example), or be used in combination with flat structures (textile materials such as fabrics, coated or not, films, etc.) in order to reinforce them or give them other properties inherent in such metallic structures.

Of course, the invention is not limited to the embodiment described above, but it covers all the variants produced in the same spirit. Thus, it could also be envisaged to make a knit in a manner similar to that described in the present application by using not a single needle bed, but the two needle beds.

Claims (3)

1 / Method for producing a knitted article based on metallic threads, which consists in producing said structure on a rectilinear loom with picked stitches, the article produced having a “jersey” type texture, characterized in that said knitted fabric jersey is obtained from three elementary yarns (1,2,3) supplied from spools arranged on the same side of the loom, knitting being carried out by making the three threads knit successively, each thread being put on hold after knitting of a row on the opposite side of its power source. 2 / knitting based on metal son obtained by the implementation of the method according to claim 1, characterized in that it is made from three elementary son forming a mesh structure of the "jersey" type, said article being perfectly flat and having rectilinear edges. 3 / Complex structure such as laminated article, flat or shaped, based on resin, planar material (fabric, film) comprising a knitted fabric based on metallic threads according to claim 2.

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