EP0681045A1 - Method for manufacturing a knitted article and a new type of knitwear manufactured this way - Google Patents

Abstract

To give a jersey knitted fabric, from a flatbed knitter, a twin needle bed is used to transfer selected stitches from one bed to the other. The fabric is developed from two yarns (F,T) where one yarn (F) gives the jersey structure and the other yarn (T) acts as a filler without knitting through the needles. The knitting cycle is three to-and-fro movements of the slide to give a jersey row on the needles of one bed and, on the return slide movement, selected stitches are transferred to the needles of the other bed in a selected sequence. On the next forwards slide movement, the second yarn (T) is laid on the loops of the transferred stitches between the two beds and, after laying, the transferred stitches are immediately returned to their original needles. On the slide return, a jersey row is formed in the other direction. During the third forwards movement of the slide, part of the knitted stitches are transferred to the needles of the other bed, with the second yarn (T) laid and stitches returned during the slide reverse movement. <IMAGE>

Description

The present invention relates to an improved process allowing the production of knitted articles, usable either as, as reinforcements, or associated with other materials, in particular incorporated inside a resin, natural or synthetic rubber in view of making flat or shaped "composite" or "laminate" articles (molded for example), in order to strengthen them and / or give them specific characteristics.

It also relates to the new type of knitting thus produced and to the complex structures incorporating such a knitting.

Among the textile structures used for the reinforcement of composite articles, in addition to woven structures, it has long been proposed to use knitwear.

In general, the choice between a woven structure and a knitted structure depends on the intended application, the knitted structures having the essential advantage of being able to be easily deformed, which makes them particularly suitable for making articles. molded. On the other hand, this deformability makes them totally unsuitable for applications in which it is necessary to have a transverse blocking.

In addition, in the field of the production of composite articles, the problem arises of producing tubular reinforcements, of constant or variable diameter, and this in different dimensions, for example to produce artides such as pipes, belts, tires, or even conical, oval, ball-shaped structures ....

The knitted articles are divided into two large families, namely those obtained according to the technique known as "tossed mesh", and the technique known as "picked mesh" implemented either on circular looms or on rectilinear looms.

The use of the picked mesh technique has been envisaged to produce knitted reinforcements, as is apparent in particular from US-A-4,242,686 or EP-A-546,962.

According to the teachings of US Pat. No. 4,242,686, it is possible to produce a tubular structure, but the articles produced have a determined diameter depending on that of the trade.

However, such jersey knitwear has the drawback of having rows of stitches arranged in a helix, which causes the article to "twist". Furthermore, if it is conceivable to lay such a tubular knit flat by cutting it along a generatrix on the edge of the structure, it lacks strength and becomes frayed given the fact that there is no selvedge .

The use of rectilinear knitting looms as taught in EP-A-0546 962, makes it possible to obtain mesh articles, flat, comprising rectilinear selvedges, reinforced, limiting the risks of unraveling.

The articles thus obtained are not, however, blocked transversely.

Furthermore, to date, no proposal has been made concerning the possibility of being able to produce, on the same type of loom, both flat knitwear and tubular knitwear.

Now we have found, and this is what is the subject of the present invention, that it was possible, by adapting the knitting technique with picked stitches used on a straight loom, to produce not only flat structures , but also tubular structures, which may be of constant or variable diameter and which, moreover, have the characteristic of being blocked transversely or circumferentially.

• le métier rectiligne utilisé est sélectionné parmi les métiers du type double fonture, permettant un transfert de mailles d'une fonture à l'autre ;
• le tricotage est réalisé à partir de deux fils, l'un travaillant selon une armure jersey, et l'autre étant tramé et ne maillant pas avec les aiguilles ;
• le cycle ou rapport de tricotage est de trois aller-retour du chariot de distribution de fil et de commande des déplacements des aiguilles, et est tel que :
  • . on réalise une rangée jersey sur les aiguilles d'une fonture du métier ;
  • . lors du retour du chariot, on transfère sur l'autre fonture une sélection, selon une séquence prédéterminée, de mailles de la rangée jersey préalablement réalisée ;
  • . lors du second aller, on dépose le deuxième fil de manière rectiligne sur les brides des mailles transférées s'étendant entre les deux fontures et, immédiatement après dépose, on retransfère lesdites mailles sur leurs aiguilles d'origine de la première fonture,
  • . lors du second retour du chariot, on réalise une rangée jersey dans l'autre sens,
  • . lors du troisième aller, on réalise le transfert d'une partie des mailles jersey ainsi réalisées sur les aiguilles de l'autre fonture et,
  • . lors du troisième retour, on dépose le deuxième fil de manière rectiligne sur les brides des mailles transférées s'étendant entre les deux fontures, et immédiatement après dépose, le transfert desdites mailles sur leur fonture d'origine.

In general, the invention therefore relates to an improved process making it possible to produce a mesh structure on a rectilinear loom with picked stitches, the article produced having a "jersey" type texture, said process being characterized in that:

• the rectilinear loom used is selected from the looms of the double needle bed type, allowing a transfer of stitches from one needle bed to another;
• knitting is carried out from two threads, one working in a jersey weave, and the other being woven and not knitting with the needles;
• the knitting cycle or ratio is three round trips of the yarn distribution carriage and control of the movements of the needles, and is such that:
  • . a row of jersey is made on the needles of a needlework;
  • . during the return of the carriage, a selection, according to a predetermined sequence, of stitches from the jersey row previously carried out is transferred to the other needle bed;
  • . during the second go, the second thread is deposited in a rectilinear manner on the flanges of the transferred stitches extending between the two needle beds and, immediately after removal, said stitches are transferred to their original needles of the first needle bed,
  • . during the second return of the carriage, a jersey row is made in the other direction,
  • . during the third round, we carry out the transfer of part of the jersey stitches thus produced on the needles of the other needle bed and,
  • . during the third return, the second wire is deposited in a rectilinear manner on the flanges of the transferred stitches extending between the two needle beds, and immediately after removal, the transfer of said stitches to their original needle bed.

Thanks to such a procedure, a knitted fabric with a jersey structure is obtained, each row of which has a straight wire trapped between the flanges of certain stitches, and which therefore ensures the transverse stability of the knitted fabric formed.

Furthermore, by proceeding in this way, it is possible to obtain not only flat knitwear, but also tubes which may have constant diameters of different dimensions and, by carrying out increases and / or decreases, to obtain flat or tubular structures of various shapes.

To obtain flat knitwear, the jersey thread is always distributed on the same needle bed, while for the production of tubular elements, the two needle beds are worked alternately, the row of jersey being made so that, according to a predetermined frequency, a needle of the needle bed on which the jersey is formed is not supplied with thread in order to allow the transfer of a stitch formed on the corresponding needle of the opposite needle bed.

The process according to the invention makes it possible to use any type of filiform material as a weft thread which does not mesh with the needles. Thus, it is possible to use both conventional threads, alone or as a mixture, which may be based on any natural or chemical material, as other filiform materials such as metallic threads, optical fibers, and this, in titles which may vary within a very wide range.

• la figure 1 est une représentation graphique conventionnelle illustrant la structure d'un tricot plat réalisé conformément à l'invention;
• la figure 2 est également une représentation graphique conventionnelle d'un tricot tubulaire réalisé conformément au procédé selon l'invention.

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

• Figure 1 is a conventional graphic representation illustrating the structure of a flat knit produced according to the invention;
• Figure 2 is also a conventional graphical representation of a tubular knit produced according to the method according to the invention.

Figures 1 and 2 schematically illustrate the manner in which the knitted structures according to the invention are produced, namely respectively a flat structure (Figure 1) and a tubular structure (Figure 2), these knits being produced on a rectilinear loom with discarded stitches, double needle bed, and which allows the transfer of stitches from the needles of the front needle bed (AV) to those of the rear needle bed (AR), and vice versa.

The knitted structures according to the invention are produced from two threads (F) and (T), one meshing with the needles in a jersey weave and the other not meshing with said needles.

In Figures 1 and 2 attached, the cross arrow indicates the direction of movement of the carriage; moreover, the references (T) and (F) used to designate the threads are positioned on the side of the needle bed where the thread is located awaiting distribution or after distribution to the needles.

In the two types of knitted structures (flat or tubular), the knitting cycle or ratio is carried out on three round trips of the yarn distribution carriage and control of the movements of the needles.

In the two embodiments, if we consider that the first movement of the carriage is from left to right, we first form (phase 1) a jersey row on the needles of a needle bed (AR in the case present) with wire F which is put on hold at the end of this row on the right of the machine.

It should be noted that in the case of a flat structure, the thread F forms a jersey knit on a single needle bed, the back needle in the present case, said thread being distributed over all the needles. In the case of a tubular structure, the rows of jersey are made alternately on the front and the back needle and, in this case, the distribution of the thread is not done on all the needles but according to a predetermined frequency, for example three, five, seven needles ..., supplied with thread for a non-supplied needle, the transferred stitch is preferably the central stitch of the sequence.

This first row of jersey being formed when the carriage returns (phase 2), a selection of jersey stitches is transferred to the second needle bed (front).

The carriage moving again from left to right (phase 3), the wire T is deposited in a rectilinear fashion on the flanges of the transferred stitches which extend between the two front and rear needle beds and immediately after removal, the stitches are transferred back to their original needlework.

The carriage then being on the right, three phases similar to phases 1, 2 and 3 are carried out to return to the starting position.

In the embodiment illustrated in FIG. 1, the second row of jersey (phase 4) is made on the same needle bed as the first row, whereas in the case of a tubular article as illustrated in FIG. 2, the yarn distribution is done on the front bed and transfer on the back bed, on needles that have not been supplied with yarn during the first row of jersey knit.

Such a procedure makes it possible to produce not only flat knits, but, as said previously, tubular knits which, in both cases, are blocked in width.

The knits in accordance with the invention can be produced on all types of looms with straight throws, allowing a transfer of the stitches from the front bed to the rear bed (or vice versa) and which, preferably, make it possible to vary the width of knitting by increases and decreases, thus obtaining flat or tubular shaped structures.

As an indication, as a type of trade, one can for example use a trade marketed by the company STOLL of CMS type.

The non-meshed wire being trapped between the flanges of the knitted stitches, is maintained in a practically rectilinear manner and therefore makes it possible to obtain a transverse (or diametral) blocking. This thread can be of any kind and size, since it is simply distributed in a rectilinear manner and is never engaged with the needles.

Such knits can be used in many applications, in particular as mentioned in the preamble to make reinforcements for reinforcing composite articles.

Such knits could of course be used in other sectors where it is desired to have tubular, cylindrical or variable-shaped structures, for example conical.

The presence of the straight wire inside the knitted fabric also allows the porosity of the latter to be modulated at will by varying the weft density.

Claims (6)

1 / Improved process allowing the production of a mesh structure having a "jersey" type texture on a rectilinear loom with picked stitches, characterized in that: - the rectilinear loom used is selected from among the looms of the double needle bed type, allowing a transfer of stitches from one needle bed to another; - knitting is carried out from two threads (F) and (T), one (F) working in a jersey weave, and the other (T) being woven and not meshed with the needles; - the knitting cycle or ratio is three round trips of the yarn distribution carriage and control of the movements of the needles, and is such that: . a row of jersey is made on the needles of a needlework; . during the return of the carriage, a selection, according to a predetermined sequence, of stitches from the jersey row previously carried out is transferred to the other needle bed; . during the second trip, the second thread (T) is deposited in a rectilinear fashion on the flanges of the transferred stitches extending between the two needle beds and, immediately after removal, the said stitches are transferred to their original needles in the first needle bed, . during the second return of the carriage, a jersey row is made in the other direction, . during the third round, we carry out the transfer of part of the jersey stitches thus produced on the needles of the other needle bed and, . during the third return, the second wire (T) is deposited in a rectilinear fashion on the flanges of the transferred stitches extending between the two needle beds, and immediately after removal, the transfer of said stitches to their original needle bed. 2 / A method according to claim 1, characterized in that the yarn F in jersey is always distributed on the same needle bed. 3 / A method according to claim 1, characterized in that the jersey yarn F is distributed alternately on the two needle beds of the loom, each row of jersey being made so that, according to a predetermined frequency, a needle of the needle bed on which form the jersey is not supplied with thread to allow the transfer of a mesh formed on the corresponding needle of the opposite needle bed. 4 / knitted article obtained by the implementation of the method according to one of claims 1 to 3, characterized in that it has a jersey-like structure, each row of which comprises a straight wire (T) trapped between the flanges of some stitches. 5 / knit according to claim 4, characterized in that it has a planar configuration. 6 / knit according to claim 4, characterized in that it is in a tubular form of constant or variable section.

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