FR2801064A1 - METHOD AND INSTALLATION FOR THE PREPARATION OF A MULTI-DIRECTIONAL FIBROUS TABLECLOTH - Google Patents

Abstract

The subject of the invention is a method for producing a multidirectional fibrous web, in which several unidirectional fibrous webs (1) are superimposed in different directions and said unidirectional webs are connected together. The method consists in forming, from at least one cable, at least one of said unidirectional plies composed of staple fibers and independent of each other, applying said unidirectional ply to a continuous and porous support strip (12), drive in translation the assembly formed by the support strip 12 and the unidirectional ply (1) by exerting traction on this support strip, maintaining the fibers of this ply on the support strip (12), separating the ply unidirectional (1) of the support strip (12) and superimposing said unidirectional ply (1) with at least one other unidirectional ply. The invention also relates to an installation for developing a multidirectional fibrous ply.

Description

The present invention relates to a method and a

  installation for developing a multidirectional fibrous web

  tional. For the production of composite parts, it is known to use multidirectional fibrous plies formed by the superposition of several fibrous plies

  unidirectional arranged in different directions

and linked together.

  Each unidirectional sheet is formed of

  which are oriented in one direction and generally

  along the longitudinal axis of said sheet.

  This type of tablecloth is obtained for example by cra-

  quage, carding, conversion or stretching with or without ba-

  at least one cable, for example carbon.

  But, the handling of this kind of tablecloth

  unidirectional burner poses problems and a technique

  commonly used is to give enough fiber

  cohesion in order to avoid their dispersion.

  One of the means to give this cohesion to

  fibers of the unidirectional sheet consists in binding them in

  be them by threads arranged in a weft or by sewing.

  The main drawback of these techniques

  side in the fact that the connecting wires create over-

  thicknesses forming ripples that can cause

  crushing and breaking of fibers in unidirectional sheets

  when superimposing and pressing these

tablecloths against each other.

  Fiber breakage can result in

  degradation of multidirectional aquifers and consequently

  harm the mechanical properties of parts made of material

  composite obtained from these multidirectional layers-

  the. To avoid this drawback, it is also known to use binding wires made of hot-melt material which at least partially melt during the preparation of the

  composite material which reduces excess thickness

sisters.

  However, it is necessary in this case that the material

  riau component binding threads is compatible with the na-

  ture of the matrix of the composite material, which limits

the use of this technique.

  Another technique also used is

  to give cohesion to the fibers of the unidirectional sheet-

  by a slight entanglement of these fibers by the application

  cation on this sheet of water or by needling.

  However, the application of a jet of water or needles can

  drag a local disorganization of the fibers of the unidirectional sheet by creating holes which can harm the

  mechanical properties of parts made of composite material.

  Another solution is to give a cohesive

  sion to the fibers of the unidirectional sheet by the addition of a chemical bonding agent which may be eliminated, for example by spraying a liquid composition onto the sheet or passing through a bath. But, such a technique

  increases the cost price of the unidirectional sheet.

  The object of the invention is to avoid these inconveniences.

  by proposing a process and an installation for

  ration of a multidirectional fibrous web from unidirectional fibrous webs which can be manipulated prior to their superposition and which have a

good surface smoothness.

  The subject of the invention is therefore a process for producing

  boration of a multidirectional fibrous web, in the-

  which one superimposes several fibrous sheets unidirection-

  nelles in different directions and said unidirectional sheets are connected together, characterized in that: - one forms, from at least one cable, at

  at least one of said unidirectional layers composed of

  discontinuous and independent of each other, - said unidirectional ply is applied to a continuous and porous support strip, - the assembly formed by the support strip and the unidirectional ply is driven in translation by exerting traction on this strip of support and at a speed substantially equal to the speed of advance of this unidirectional ply, - the fibers of this ply are maintained on the support strip, - the unidirectional ply is separated from the support strip, - and said ply is superimposed unidirectional

  with at least one other unidirectional sheet.

  According to other characteristics of the invention:

  - Maintaining the fibers of said layer

  directional on the support strip by suction through

  towards said strip, - the fibers of the unidirectional sheet are

  in a material chosen from carbon, glass, cereals

  mics, aramids, silicon carbide or fibers

  mineral, or hot melt fibers or thermal fibers

  adhesive or any mixture of these fibers, - the support strip is made of a textile material

  made from a material chosen from polyethylene

  lene, polyamide, polyester, polypropylene or viscose.

  The invention also relates to an installation

  tion of developing a multidirectional fibrous web

  produced by superimposing unidirectional fibrous layers

  in different directions and linked between them

  , characterized in that it comprises: - means for forming, from at least one cable, at least one of said unidirectional sheets composed of staple fibers and independent of each other, - means of unwinding d 'a continuous band

  and porous, for supporting the fibers of said unidirectional sheet

  tional, - drive means in translation of

  the assembly formed by the support strip and the unidi-

  directional by exerting traction on this support strip and at a speed substantially equal to the speed of advance of this sheet after its formation, - means for holding the fibers of the unidirectional sheet on the support strip during its transport ,

  - means for separating the unidirectional sheet

  of the support strip, and means for superimposing said sheet

  unidirectional with at least one other unidirectional tablecloth

tional.

  The subject of the invention is also a sheet

  unidirectional flailer, characterized in that it is formed of staple fibers independent of each other

  others obtained from at least one cable for confection

  at least one multidirectional tablecloth.

  The invention will be better understood on reading

  the description which follows, given by way of example and

  made with reference to the accompanying drawings, in which:

  - Fig. 1 is a schematic elevational view

  lateral tion of a first embodiment of an installation

  development of a unidirectional fibrous web, - Figs. 2 and 3 are two schematic side elevational views of a second embodiment of a

  installation for developing a unidirectional fibrous web

tional,

  - Fig. 4 is a schematic perspective view

  tive of a support strip of the unidirectional fibrous web

tional.

  In Figs. 1 to 3, there is shown diagrammatically

  only two embodiments of an electrical installation

  boration of a unidirectional fibrous ply intended to form a multidirectional ply by superposition and bonding of several unidirectional plies, at least one of which is composed of staple and independent fibers

each other.

  The unidirectional fibrous web, designated

  by the reference 1, is obtained in the examples of reali-

  sation shown in the figures, by cracking at least

a cable.

  The unidirectional fibrous web can be obtained by other methods such as, for example, carding, converting or drawing with or without a bar.

  For example, the fibers of the unidi-

  are in a material chosen from carbon,

  glass, ceramics, aramids, silicon carbide

  cium or mineral fibers or hot melt fibers or

  fusible fibers or any mixture of these fibers.

  The installation according to the invention makes it possible to

  lining unidirectional fibrous webs composed of staple fibers and independent of each other, without a device for tying these fibers and therefore

  without the creation of faults which could harm the properties

  canics of composite material parts made from

  of these unidirectional fibrous sheets.

  According to a first embodiment shown in FIG. 1, the installation comprises a cracking unit for example designated as a whole by the reference 10,

  at the outlet of which the uniform fibrous web is formed

  rectionnel 1 composed of staple fibers and independent

each other.

  The installation also includes a coil 11

  carrier of a continuous and porous strip designated by the

  ference 12 and which is progressively unwound below the unidirectional ply 1 so as to form a band

  continuous support for the fibers of said unidi-

  1 for transporting and handling this

tablecloth.

  As shown in FIG. 1, the installation also includes rollers 14 for guiding the assembly

  formed by the support strip 12 and the unidirectional ply

  nelle 1, means 15 for translational drive of this assembly by exerting traction on the support strip 12

  and means 20 for holding the fibers of the uniform ply

  1 on the support strip 12 during transport. The rollers 14 are mounted free in translation and ensure the guidance of the assembly formed by the support strip 12 and the unidirectional ply 1 to the station for separating this unidirectional ply 1 from said support strip 12 o the unidirectional plies 1 are

  superimposed in different directions so as to form

  sea a multidirectional tablecloth, not shown, which is

  used for the development of composite parts.

  During its transport, the fibers of the unidirectional sheet 1 are held on the support strip 12 by the means 20 which are formed by a system

  suction 21 disposed on the path of said unidi-

  section 1 and below the support strip 12.

  For this purpose, the support strip 12 is produced

  in a porous material such as for example a textile material.

  The means 20 for holding the fibers of the unidirectional ply 1 on the support strip 12 can be

  constituted by any other system such as for example a system

  blow molding arranged above the ply 1 or also by free rotating rollers also arranged above the ply 1 and which flatten the fibers of this

ply on the support strip 12.

  As shown in Fig. 1, the installation also includes means 25 for winding the support strip 12 so as to form a reel 11 which allows the

  transport and reuse of this support strip 12.

  The means 25 for winding the support strip

  12 consist of a cylinder 26 for winding the

  said strip 12 mounted free in rotation and vertically movable

calmly.

  For this purpose, each end of the axis 27 of the cy-

  lindre 26 is mounted in a slide 28 in such a way

  that the cylinder 26 rises gradually during the in-

  rolling of the support strip 12 on said cylinder 26.

  For this, the means 15 for driving the support strip 12 act on the external face of said

  support strip 12 during its winding on the cy-

  lindre 26 so as to exert a traction only on this support strip 12 without modifying the homogeneity of the fibers of the unidirectional ply 1 during its

  transfer between the cracking unit 10 and the processing station

  ration of the multidirectional tablecloth.

  According to an embodiment shown in FIG. 1, the drive means of the assembly formed by the

  unidirectional ply 1 and the support strip 12

  an endless strip 16 forming a loop and comprising at each of its ends a roller 17. One of the rollers is motorized so as to drive this endless strip 16 in translation at a speed substantially equal to the speed

  in advance of the unidirectional sheet at the exit of the uni

cracking tee 10.

  This endless band 16 is in contact with the

  external face of the support strip 12 which allows to exert-

  cer on this support strip 12 sufficient traction

  to move the assembly formed by the unidirectional sheet-

  nelle 1 and said support strip 12.

  According to a variant, the drive means

  are formed by at least one horizontal roller, preferably

  rence by a train of rollers at least one of which is rotated at a speed substantially equal to the speed

  in advance of the unidirectional sheet after its formation.

  These rollers are in contact with the external face of the

support strip 12.

  The drive roller can be fitted with each

  one of its spike ends cooperating with the selvedges

of the support strip 12.

  According to another embodiment, the installation

  tion is divided into two parts, a first part represented

  felt in FIG. 2 and a second part shown in

Fig. 3.

  As for the previous embodiment, the first part shown in FIG. 2 comprises a cracking unit 10 for obtaining, from at least one cable,

  a unidirectional sheet 1 made up of disconti-

  naked and independent of each other and the means of unwinding a reel there of a continuous and porous strip

  to form a support for the fibers of the unidirectional sheet-

1.

  This first part also includes means 20 for holding the fibers of the unidirectional ply 1 on the support strip 12 during its transport and which

  are constituted by a suction system 21 disposed above

under the support strip 12.

  Finally, the first part of the installation includes

  carries means 30 for winding the assembly formed by the unidirectional sheet 1 and the support strip 12 so as to produce a reel 31 which can be stored and transferred in the second part of the installation to produce a multidirectional fibrous sheet with from said tablecloth

unidirectional 1.

  The support strip 12 makes it possible to protect the fibers of this sheet and to maintain the consistency of said layer.

unidirectional cable 1.

  As shown in FIG. 2, means 30

  winding of the assembly formed by the unidirectional sheet-

  nelle 1 and the support strip 12 are constituted by a cy-

  lindre 32 of winding of said assembly mounted free in rotation

  tion and movable vertically and by means 35 of-

  drag acting on the external face of the support strip

  port 12 during its winding so as to exert a

  traction only on said support strip 12.

  For this, each end of the axis 33 of the cy-

  winding strip 32 is mounted in a slide 34 which allows said cylinder 32 to move upward at

  as the coils wrap around this cy-

lindre 32.

  In the exemplary embodiment shown in FIG. 2, the drive means 35 are formed by an endless belt 36 forming a loop provided at each of its

  ends of a guide roller 37.

  One of the rollers 37 is motorized so as to drive the endless belt 36 in translation at a speed

  substantially equal to the speed of the unidirectional sheet-

after her training.

  This endless strip 36 is in contact with the external face of the support strip 12 so as to exert on this support strip 12 a traction making it possible to

form the coil 31.

  According to a variant, the drive means

  are formed by at least one horizontal roller and preferably

  rence by a train of rollers at least one of which is rotated at a speed substantially equal to the speed

  in advance of the unidirectional sheet 1 after its formation.

  The rollers are in contact with the face ex-

  dull of the support strip 12 which allows printing to

  this support strip 12 a traction to allow the

  bearing of the assembly including the unidirectional tablecloth-

nelle 1 and the support strip 12.

  The motorized roller can be provided at each of its ends with pins cooperating with the edges of the

support strip 12.

  The coil 31 thus produced is transferred to the second part of the installation, shown in FIG. 3. This second part of the installation comprises means 40 for unwinding the coil 31 and means 50

  of winding the support strip 12 to allow its re-

  use in the first part of the installation.

  The means 40 for unwinding the reel 31 are

  formed by a support consisting of two slides 41 intended

  born each to receive one end of the axis 33 of the cylinder

winding dre 32.

  Thus, the coil 31 is mounted to rotate freely in the slides 41 and can be moved vertically at

  means of a support member 45 which cooperates with the face ex-

dull support strip 12.

  According to the embodiment shown in FIG. 3, the support member 45 is formed by an endless band 46 which forms a loop provided at each of its ends

  a guide roller 47 free to rotate.

  Therefore, the endless belt 46 is free in translation and has the role of supporting the coil 31 at

during its unwinding.

  At the end of the endless belt 46, the installation

  tion comprises a suction system 21 which keeps the fibers of the unidirectional ply 1 on the support strip 12 up to the station for preparing the

  multidirectional sheet from said unidirectional sheet

tional 1.

  According to a variant, the support member 45 of the coil 31 can be formed by at least one horizontal and freely rotating roller which is in contact with the external face.

of the support strip 12.

  The means 50 for winding the support strip

  port t12 are formed by a winding cylinder 51

  carrying an axis 52 whose each end is mounted free in

rotation in a slide 53.

  Thus, the cylinder 51 is movable vertically-

* as and when the support strip is wound up

port 12.

  The winding means 50 also comprise drive means 55 acting on the external face of

  the support strip 12 during its winding.

  According to a first embodiment, the drive means consist of an endless belt 56 which forms a loop comprising at each of its ends

a guide roller 57.

  One of the rollers 57 is driven in rotation which makes it possible to exert, by means of the endless belt 55, a traction only on the support strip 12 and to move via the support strip 12 , the fibers of the unidirectional sheet of the coil 31

  to the multi-directional tablecloth workstation-

  nelle. According to a variant, the drive means 55 can be formed by at least one horizontal roller and

  preferably by a train of rollers of which at least one is

  dragged in rotation. These rollers are in contact with the external face of the support strip 12 and one of the rollers

  can be fitted at each of its ends with co-pins

  rant with the edges of the support strip 12.

  The installation may also include, at the outlet of the unit for forming the unidirectional sheet 1, means for spraying a surfactant or

  water to increase the cohesion of the unidi-

1.

  The support strip 12 is advantageously

  aligned in a porous material to allow the aspiration of the fibers of the unidirectional sheet 1 through said support strip and this porous material is preferably a textile made from a material chosen from polyethylene, polyamide, polyester, polypropylene

or viscose.

  As shown in FIG. 4, the strip

  support 12 has, on each of its edges, a bulge

  continuous reel 12a and has a slightly greater width

  less than the width of the unidirectional sheet 1.

  This support strip 12 must reconcile more

  several characteristics which are finesse, lightness, resistance, porosity to facilitate aspiration and must

  also have a slight surface roughness.

  The finesse and lightness as well as the resistance

  tance are linked and depend on the thread title and the ma-

third used.

  For example, the titles are between / 1 and 200/2, in 1 or 2 ends, in continuous thread or spun with fibers. We obtain textiles between 20 and 200g / m2 for a

thickness of the order of 1 / 10mm.

  The minimum resistance is for example gold-

  dre of 3OcN / tex and the support strip 12 present for example-

  full of square pores whose dimensions are included in-

be 2 / 10mm and 7 / 10mm.

  This support strip prevents tangling between the turns during winding and unwinding and also allows the unidirectional sheet to be moved, avoiding any traction on the fibers of this sheet so as to save them a force which can disorganize the homogeneity of the

  fibers of the unidirectional sheet.

  The unidirectional sheet thus obtained which is made up of staple and independent fibers

  another is used to form a multidirectional sheet

  by superimposing several unidirectional layers and connecting them together, for example by sewing, by

  knitting, by needling or by gluing.

  According to a variant, the porous strip can be used for transporting and / or storing at least one

  multidirectional tablecloth composed of several uni-tablecloths

  directional superimposed and not interconnected.

  The unidirectional sheet can be made at

  from several cables of the same type or of different types

férentes.

  Similarly, the multidirectional sheet can be obtained by superimposing in different directions the

  Unidirectional tablecloths of the same kind or of different natures

férentes.

Claims (28)

  1. Method for making a fibrous web   multidirectional, in which we overlap several nap-   unidirectional fibrous pes (1) in different directions and said unidirectional plies (1) are connected together, characterized in that: - at least one cable is formed at   at least one of said unidirectional layers composed of   discontinuous and independent of each other, - said unidirectional sheet (1) is applied to a continuous and porous support strip (12), - the assembly formed by the support strip (12) and the sheet is brought into translation unidirectional (1) by exerting a traction on this support strip (12) and at a speed substantially equal to the speed of advance of this unidirectional ply (1), - the fibers of this ply (1) are kept on the strip of support (12), - the unidirectional ply (1) is separated from the support strip (12), - and said unidirectional ply is superimposed   (1) with at least one other unidirectional sheet.   2. Method according to claim 1, characterized   in that the fibers of said uniform ply are maintained   directional (1) on the support strip (12) by suction across said strip.   3. Method according to claim 1 or 2, charac-   terized in that after the formation of the unidirectional sheet-   nelle (1), the fibers of said uniform sheet are sprayed   directional a surfactant or water.   4. Method according to any one of the claims   previous operations, characterized in that before the separation between the unidirectional sheet (1) and the support strip   (12), the assembly formed by the unidirectional sheet is wound   nelle (1) and the support strip (12) at a speed   roughly equal to the speed of advance of this unidirectional sheet   tional (1) after its formation, this set is stored, then the said set is unwound and, after the separation between said unidirectional sheet (1) and the support strip (12), this support strip (12) is wound at a speed   substantially equal to the speed of progress of said set corn.   5. Method according to any one of the claims   tions, characterized in that the fibers of the   said unidirectional sheet (1) are made of a material chosen from carbon, glass, ceramics, aramids, silicon carbide or mineral fibers or hot-melt fibers or fusible fibers or any mixture of these fibers.   6. Method according to any one of the claims   1 to 4, characterized in that the support strip (12) is made of a textile material.   7. Method according to claim 6, characterized in that the textile of the support strip (12) is made from a material chosen from polyethylene,   polyamide, polyester, polypropylene, viscose.   8. Method according to claim 6 or 7, charac-   terrified in that the textile has pores for example   square, with dimensions between 2 / 10mm and 7 / 10mm.   9. Method according to any one of the claims   tions 6 to 8, characterized in that the support strip (12) has on each of its selvedges a continuous bead (12a).   10. Method according to any one of the claims.   cations 6 to 9, characterized in that the support strip (12) has a width slightly greater than the width of the unidirectional band.   11. Method according to any one of the claims.   cations 1 to 5, characterized in that the unidirectional layer   nelle (1) is obtained by cracking, carding, converting or stretching with or without bar.   12. Installation for the production of a water table   multidirectional crusher produced by superposition of unidirectional fibrous layers (1) in different directions and connected to each other, characterized in that it comprises: - means (10) for forming, starting from at   at least one cable, at least one of said unidirectional layers   nelles composed of staple fibers and independent of each other, - means (11) for unwinding a continuous and porous strip, for supporting the fibers of said unidirectional sheet (1), l0 - means (15; 35; 55 ) for translational drive of the assembly formed by the support strip (12) and the unidirectional ply (1) by exerting traction   on this support strip (12) and at a substantial speed   ment equal to the speed of advance of this ply after its formation, - means (20) for holding the fibers of the unidirectional ply (1) on the support strip (12) during its transport,   - means for separating the unidirectional sheet   tional (1) of the support strip (12), - and means for superimposing said sheet   unidirectional (1) with at least one other unidi- rational.   13. Installation according to claim 12, ca-   characterized in that it comprises means (30) for winding   swimming of the assembly formed by the unidirectional sheet (1) and the support strip (12).   14. Installation according to claim 12, ca-   characterized in that it comprises means (40) for deviating   dage of a coil (31) of the assembly formed by the uniform web   directional (1) and the support strip (12).   15. Installation according to claim 12, ca-   characterized in that it includes means (25; 50) for   winding of the support strip (12).   16. Installation according to claims 12 and   13, characterized in that the means (30) for winding   all are formed by a cylinder (32; 33) of winding   ment of said assembly mounted free in rotation and movable vertically and by said drive means (35) acting on the external face of the support strip (12) at during its winding.   17. Installation according to claims 12 and   14, characterized in that the means (40) for unwinding the   coil (31) are formed by a support (41) on which the   said coil (31) is mounted free in rotation and displaceable   vertically and by a support member (45) on the face ex- dull support strip (12).   18. Installation according to claim 17, ca-   characterized in that the support member (45) is formed by a   endless band (46) free in translation.   19. Installation according to claim 17, ca-   characterized in that the support member is formed by at least   a horizontal and free rotating roller.   20. Installation according to claim 12, ca-   characterized in that the means (25; 50) for winding the support strip (12) are formed by a cylinder (26, 27;   51, 52) for winding said strip mounted free in rotation   tion and movable vertically and by said drive means (15;) acting on the external face of the strip   support (12) during its winding.   21. Installation according to claim 16 or   20, characterized in that the means (15; 55) for driving   ment are formed by an endless belt (16; 56) driven in translation at a speed substantially equal to the speed   in advance of the unidirectional sheet (1) after its formation   tion and in contact with the external face of the support strip port (12).   22. Installation according to claim 16 or   , characterized in that the means (15; 55) for driving   are formed by at least one horizontal roller and   dragged in rotation at a speed substantially (1) equal to the   advance speed of the unidirectional sheet after its formation   mation and in contact with the external face of the support (12).   23. Installation according to claim 22, ca-   characterized in that said roller is provided at each of its ends with pins cooperating with the edges of the strip of support.   24. Installation according to claim 12, characterized in that the means (20) for holding the fibers of the unidirectional sheet (1) on the support strip (12) are formed by a suction system (21) arranged   below said support strip (12).   25. Installation according to any of the   vendications 12 to 24, characterized in that it comprises means for spraying a surfactant or   water on the fibers of said unidirectional sheet (1).   26. Unidirectional fibrous web, characteristic   se in that it is formed of staple fibers and inde   dangling from each other obtained from at least   a cable for making at least one multidirectional sheet tional.   27. Tablecloth according to claim 26, character-   sée in that it is carbon fiber, glass, ce-   ramic, aramid, silicon carbide or mid-fiber   or hot-melt fibers or hot-melt fibers   sticky or any mixture of these fibers.   28. Compressed multidirectional fibrous web   nant several unidirectional layers (1) superimposed   in different and interconnected directions,   characterized in that it comprises at least one unidi-   rectionnel (1) according to claim 26 or 27.