WO2014013141A1

WO2014013141A1 - Fibre application machine with means of transporting fibres on continuous belts

Info

Publication number: WO2014013141A1
Application number: PCT/FR2013/000173
Authority: WO
Inventors: Yvan Hardy; Alexander Hamlyn; Johann Caffiau
Original assignee: Coriolis Composites
Priority date: 2012-07-17
Filing date: 2013-07-04
Publication date: 2014-01-23
Also published as: FR2993491A1; FR2993491B1

Abstract

The present invention relates to a fibre application machine for producing parts made up of composite materials, a method for producing a preform and a method of producing a part made up of composite material. The machine comprises transport means to transport fibres from storage means to an application head, which comprises at least one continuous belt (3, 4) extending between the head and the fibre storage means, mounted between an upstream return system (38, 48) and a downstream return system (39, 49), said continuous belt comprising an outgoing strand (32, 42) against which a fibre can come into contact without sliding.

Description

FIBER APPLICATION MACHINE WITH CONTINUOUS BAND FIBER DELIVERY MEANS

The present invention relates to a fiber application machine for producing parts made of composite material, and more particularly means for conveying particular fibers of such a machine for conveying fibers from fiber storage means to the head. application. The present invention also relates to a method of producing a preform by applying fibers to a tool, and to a method of producing a composite material part from such a preform.

Fiber application machines are known for the contact application on a draping tool, such as a male or female mold, of a wide band formed of one or more continuous fibers, also called continuous bits, in particular ribbon type flat fibers, dry or impregnated with thermosetting or thermoplastic resin, especially carbon fibers consisting of a multitude of carbon threads or filaments. These machines, called fiber placement machines, conventionally comprise a system for moving a fiber application head, said head comprising a so-called application roller or compaction, intended to come into contact against the mold to apply the strip, and guiding means for guiding the fiber or fibers on said roll. These machines further include fiber storage means, and routing means for conveying fibers from said storage means to the head.

In the case of a strip _s formed of several flat fibers, the guidance system of these machines make it possible to cause the fibers on the roll in the form of a web, wherein the fibers are arranged substantially parallel edge to edge, or with a defined spacing between two adjacent fibers. The head conventionally comprises, as described in particular in patent document WO2008132299, cutting means for individually cutting each fiber, re-routing means for rerouting each fiber that has just been cut, in order to be able to stop and resume at any time. applying a fiber, as well as choosing the width of the band, and locking means for blocking a fiber that has just been cut.

The fiber conveying means conventionally comprise, as described for example in patent document EP 1 719 610, pulley systems arranged along the various axes of displacement of the displacement system. These pulley systems are complex in design, tend to become clogged, and bulky and heavy, which limits draping speeds.

It has also been proposed, particularly in document WO2008 / 122709, to use routing means comprising flexible tubes extending storage means to the application head, each flexible tube being able to receive a fiber in its internal passage. The flexible tubes have a length and flexibility sufficient not to limit the movement of the head movement system. Each flexible tube may be provided with a longitudinal flexible blade of rectangular cross section, said flexible blade being disposed substantially parallel to the transport plane of the fiber received in the internal passage of the flexible tube.

Such flexible tubes are simple routing means of design, space and reduced costs, allowing in particular to obtain high speeds of scrolling, to deport the storage means relative to the displacement system, and to simplify the application head displacement system, in particular to use a displacement system such as a poly-articulated arm type six-axis robot. In the case of pre-impregnated fibers, it is preferable to cool the fibers in the tubes, in order to prevent clogging of the tubes, and to limit the friction between the fibers and the tubes.

In order to improve the sliding of the fibers in the tubes, and to prevent the filaments of the fibers from separating as they pass through the tubes, in particular in the case of dry fibers, fluidization means are advantageously provided for fluidizing the fibers during their transport in the tubes, these means comprising an air injection system and / or a vibrating system.

The purpose of the present invention is to propose a new solution for conveying the fibers to the head, which allows in particular to easily convey different types of fibers, dry or impregnated with resin, without damaging them.

For this purpose, the present invention provides a fiber application machine comprising

a fiber application head, comprising for example an application roller and fiber guiding means on said application roller,

fiber storage means disposed at a distance from said head, and

routing means for conveying the fibers of said storage means to the application head,

characterized in that said conveying means comprise at least one endless belt, extending between the head and the fiber storage means, mounted between an upstream return system disposed on the side of the storage means and a return system downstream disposed on the side of the head, said endless band comprising a forward strand against which a fiber is adapted to come into contact, substantially without slipping.

According to one embodiment, said routing means comprise at least one pair of endless belts extending between the head and the fiber storage means, comprising

a first endless band mounted between first upstream return means of the upstream return system, and first downstream return means of the downstream return system, and

a second endless band mounted between second upstream return means of the upstream return system, and second forward return means of the downstream return system,

the first endless belt and the second endless belt having inner strands or strands going parallel to each other and arranged vis-à-vis, able to receive between them, substantially without sliding, at least one fiber.

According to the invention, for its delivery of the storage means to the head, each fiber passes on the forward strand of an endless band, and preferably between the strands go of two endless bands. Such conveying means according to the invention allow the transport of a large variety of fibers, without deterioration of the fibers, or means of routing. The endless belts make it possible, in particular, to convey fragile flat fibers, such as dry carbon fibers, avoiding the separation of the filaments constituting it, especially when the fibers are formed from a unidirectional slit band, commonly called "slit". tape ". These endless belts also make it possible to convey so-called hard fibers, such as glass fibers, without deterioration of the endless belts. Such routing means make it possible to route fibers over a long distance.

The non-slip contact between the fiber and the one or more strands results from the long length of the strands going, and / or portion (s) curved (s) of strand go and / or pressing means, for example of galet type, at which the fiber is pinched against the strand to go or between the strands go. The fiber may be in contact with the one or more strands going their entire length, or only on one or more portions of strand go.

The endless belts may extend from the storage means to the head or to only part of the path between the storage means and the head. Preferably, especially in the case of a movable head mounted on a displacement system, for example at the end of a poly-articulated arm, the endless band or bands extend at least from the head, the system downstream discharge gear mounted on the head. Depending on the type of movement of the head, the fibers are in contact only by one of their faces against the conveying means. In such a case, the routing means may comprise only one endless band for routing a fiber.

Preferably, the endless belts extend storage means to the head. In a variant, the routing of each fiber from the storage means to the head is carried out by several pairs of endless belts, for example two pairs of endless belts, the fiber passing between the endless strands of endless belts. first pair then in between the strands go bands of a second pair.

The application machine according to the invention can be

a tape placement machine for application in contact with a wide band formed of a broad ribbon-like fiber or bit; a so-called fiber placement machine for application in contact with a wide band formed of several fibers or wicks, in particular of the ribbons type, or

a machine for non-contact application, for example a filamentary winding machine for applying a strip formed of one or more ribbon-type fibers.

The machine is preferably a fiber placement machine, comprising a fiber placement head with a compaction roller, the machine preferably comprising a head displacement system.

According to one embodiment, the downstream return system is mounted on the head, the upstream return system being disposed at a distance from the head, at said storage means or between said storage means and the head.

According to one particular feature, the one or more strands go into the internal passage of a flexible main tube, preferably of rectangular cross-section. In the case of a pair of endless bands, the strands go from the first and second endless bands pass in the same main tube. The main tube ensures the maintenance vis-à-vis the two strands go, and the lateral maintenance of the fiber between the two strands go. When draping, only the forward strands are in sliding contact with the main tube. During their transport, the fibers are perfectly isolated from the outside, and do not rub against any element. Preferably the conveying means comprise for each pair of endless belts a main tube receiving the strands go endless belts.

According to another particularity, the return strand or strands each pass through the internal passage of a flexible secondary tube, preferably of rectangular cross-section. In the case of a pair of endless belts, the return strand of the first band passes into the internal passage of a first flexible second tube, and the return strand of the second endless band passes into a second flexible secondary tube. Preferably, the conveying means comprise, for each pair of endless belts, two secondary tubes each receiving the return strand of the endless belts. These conveying means comprising endless bands combined with tubes in which are placed the Go strands, and preferably back strands, makes it possible to provide simple and easy fiber routing from the storage means to the head, in particular when the head is moved relative to the storage means via a machine moving system. The flexible tubes have a length and flexibility sufficient to not limit the movements of the displacement system.

According to one embodiment, the main tube and the secondary tube or tubes are placed in a so-called holding tube or guiding tube, flexible, preferably annealed, so that said holding tube maintains the main tube and the tube or tubes against each other, while preferably allowing a relative longitudinal movement of the main tube and the secondary tubes relative to each other. In the case of a pair of endless belts, the holding tube holds the first and second secondary tubes on either side of the main tube.

According to one embodiment, the conveying means comprise at least one longitudinal flexible blade of rectangular cross section, associated with the main tube, said flexible blade being disposed substantially parallel to the transport plane of the fiber received in the internal passage of the main tube for example between two strands go. The flexible blade associated with each tube limits or prevents the transverse bending of the main tube in the plane of the blade, which makes it possible to eliminate, or at least limit, the risks of overturning the one or more of the forward strands and the fiber arranged in the internal passage of the flexible tube parallel to the blade, in particular during certain movements of the displacement system, due to excessive bending of the tubes and / or excessive friction or strands go into the tubes. The main tube can perform bending movements in a direction perpendicular to the plane of the blade and twisting movements to allow movement of the fiber placement head in all directions. The retention of the blade against the main tube is provided by the holding tube. The blade is held directly against the main tube, or indirectly against the main tube, with a secondary tube interposed between the blade and the main tube. According to one embodiment, the flexible blade is placed between the main tube and a secondary tube. The blade flexible extends over substantially the entire length of the main tube, the main tube and the flexible blade being assembled by their end portions to fastening systems so as to allow a relative longitudinal displacement of the flexible blade relative to the first tube flexible. According to one embodiment, the flexible blade is fixedly assembled by its end portions to the fastening systems, the main tube and the possible secondary tubes are assembled with a longitudinal freedom of movement by at least one of its portions. end to one of the fastening systems.

According to one embodiment, for the application of a strip formed of several fibers, the conveying means are capable of conveying a plurality of fibers, and comprise an endless band or a pair of endless bands by fiber. In the case of endless belt pairs, the forward strands of each pair of strips receive a fiber between them, and preferably a main tube is associated with each pair of endless belts to receive the forward strands, and / or two tubes. secondary are associated with each pair of endless bands to receive back strands.

According to one embodiment, the rerouting means comprise for each fiber a pair of endless belts, a main tube for receiving the strands go, secondary tubes for receiving the return strands, a holding tube for receiving the main tube and the secondary tubes and at least one flexible blade.

According to another embodiment, in particular in the case of a head displaceable in one direction, or in two perpendicular directions, the main tubes and the secondary tubes for the conveyance of several endless belts, in particular of all endless belts, are placed in the same holding tube, the same flexible blade can be used for several pairs of endless belts, especially for all endless belts.

According to one embodiment, the machine comprises rerouting means able to act on at least one forward strand and / or a return strand of an endless band to drive said strand, and thus cause the fiber in contact with said strand without end, for example to reroute the fiber just cut to the roll, or to reroute the fiber from the storage means to the head. The rerouting means according to the invention act on the endless belts, without direct contact with the fibers, thus avoiding any deterioration of the latter during their rerouting.

According to one embodiment, the rerouting means comprise pulleys and / or motorized rollers of the downstream return system.

According to another embodiment, the aforementioned conveying tubes are replaced by pulleys or cylinders. For each fiber, the conveying means comprise at least one endless band, the endless band being supported by its face opposite the fiber against one or more rolls or pulleys arranged between the upstream and downstream return systems. In the case of pairs of endless belts, the endless belts are able to bear against their face opposite the fiber against one or more rollers or pulleys arranged between the upstream and downstream return systems.

According to one embodiment, in the case of pairs of endless belts, said redirection means are arranged in the head, and act on the two ends of endless belts, upstream of the downstream return system of the two endless belts .

According to another embodiment, said rerouting means are arranged at a distance from the head, on the side of the upstream return system, and preferably act on the return strand of an endless band. The re-routing means and deported from the head can limit the size and complexity of the head.

The rerouting means may comprise a counter-roller and a drive roller arranged facing each other, on either side of the forward strands or said return strand, the counter-roller being operable between a rest position and an active position to press the two strands go or said return strand against the drive roller to drive them positively and thus reroute the fiber.

According to another embodiment, the rerouting means comprise a rerouting conveyor and two clamping members arranged on either side of a strand of the rerouting conveyor and the return strand of the endless belt, in Particular of the return strand of one of the two endless bands of the pair, the two members being operable between an inactive position and an active clamping position in which the two members are able to clamp between them the strand of the conveyor and the strand back to positively drive the strand back via the conveyor routing. This arrangement ensures a precise re-routing of the fibers via the endless belts, without friction between the re-routing system and the endless belts, and thus without deterioration of the endless belts.

According to one embodiment, the machine comprises locking means capable of blocking, preferably individually, each fiber that has just been cut. According to one embodiment, the downstream return system is placed on the head, the machine comprises locking means are capable of pinching the strands go to block the fiber placed between them.

According to one embodiment, when the rerouting means act the return strand of one of the endless belts, a tensioning system is associated with the rerouting means, in order to tension the return strand between the locking means and the rerouting means. before the rerouting operation, and thus ensure a re-routing of the fibers to a precise length.

According to one embodiment, the machine comprises a tension limiter system comprising at least one cylinder on which the endless belt passes, or at least one of the endless belts of each pair of endless belts, and means for driving to rotate said cylinder so that the peripheral speed of the cylinder is greater than the speed of travel of the fiber at the head, so as to limit the call voltage of the fiber at the head to a value substantially constant, regardless of the speed of travel of the fiber.

According to one embodiment, the upstream return system forms the cylinder or cylinders of said voltage limiter system.

According to one embodiment, the voltage limiter system comprises a plurality of cylinders parallel to each other, on which the forward strands of each pair of endless belts are able to partially wind up, the drive means being able to drive in rotation. said cylinders, at substantially the same speed, said driving means being controlled by a control unit of the machine, so that the peripheral speeds of the rolls are greater than the speeds of travel of the fibers at the application roller, to exert a tensile force on the fibers coming from the storage means, in order to limit the fiber call voltage at the application roller to a substantially constant value, regardless of the speed of travel of the fibers. The drive means are controlled so that the peripheral speed of the rolls is greater by 20 to 40%, for example by about 30%, at the higher fiber running speed.

According to one embodiment, the machine comprises cutting means capable of cutting, preferably individually, each fiber. These cutting means can be placed conventionally in the head. According to another embodiment, the downstream return system is placed in the head, the machine comprises cutting means adapted to cut preferably individually, each fiber upstream of the upstream return system. The cutting means and deported from the head can limit the size and complexity of the head.

The fibers can thus be cut upstream of the endless belts, away from the head, and successive fiber sections, of lengths less than that of the forward strands, can be routed via the endless belts.

According to one embodiment, the machine comprises means for heating the one or more strands used for conveying each fiber, in order to preheat the fiber conveyed by said at least one strand, the endless band (s) being preferably metallic . The heating means comprise, for example, one or more heating rollers over which the endless belts pass, said rollers being arranged on the side of the storage means and possibly forming part of the upstream return system. This preheating makes it possible to soften the resin of pre-impregnated fibers or the binder of dry fibers, in order to promote the adhesion of the strips together during the draping. Additional heating means, known per se, may further be provided at the head to heat the fibers before application and / or bands already applied to the mold. According to one embodiment, the machine comprises a displacement system for moving the fiber application head.

The present invention also relates to a process for producing a preform comprising the conveyance of fibers from storage means to a fiber application head, and the application of said fibers by the application head to a tooling relative movement of the head relative to the tooling, characterized in that for the routing of each fiber, said fiber is brought into contact, substantially without slipping, with the strand to go of at least one band. Preferably, said fiber is in non-slip contact with the forward strand of at least one endless band. According to one embodiment, said fiber is interposed between the two strands go opposite a pair of strips, preferably a pair of endless bands, said fiber being in substantially no slip contact with said two strands.

According to embodiments,

the rerouting of a fiber is carried out by the strip or the pair of strips, by action on at least one of the strands of a strip, and / or

during draping, the fiber is positively driven by the band or the pair of strips in order to limit the call voltage of the fiber at the level of the application roll of the head, and / or

- The blocking of a fiber after a cutting operation is performed by the band, preferably by pinching at least one of the strands of one of the endless bands, in particular by pinching the two strands go, and / or

heating the fiber during its routing by heating the strand or strands to soften the resin and / or the binder of the fiber.

The fibers applied may be dry fibers, dry fibers provided with a binder conventionally called "binder", to impart a stickiness to the fibers during draping, such as so-called powdered fibers or veiled fibers, and / or fibers. pre-impregnated with a thermoplastic or thermosetting resin. The fibers are continuous and preferably comprise a multitude of continuous or non-continuous yarns or filaments. The present invention also relates to a method of producing a composite material part comprising a step of curing a preform obtained according to the method defined above, after a possible step of adding resin to the preform. In the case of a lay-up of fibers pre-impregnated with resin, the preform, said pre-impregnated, is subsequently cured or polymerized by passing through an oven to obtain a piece of composite material. In the case of dry fibers, with or without a binder, resin is injected or infused into the dry preform prior to the hardening step.

The invention will be better understood, and other objects, details, features and advantages will become more clearly apparent from the following detailed explanatory description of particular embodiments currently preferred of the invention, with reference to the accompanying schematic drawings, on which ones :

FIG. 1 is a diagrammatic perspective view of conveying means according to a first embodiment of the invention for conveying a fiber from storage means to a head of a fiber placement machine;

- Figure 2 is a schematic longitudinal sectional view of the conveying means of Figure 1;

- Figure 3 is a schematic cross-sectional view of the conveying means of Figure 1;

- Figure 4 is a schematic view similar to that of Figure 2 illustrating a first embodiment;

- Figure 5 is a schematic view similar to that of Figure 2 illustrating a second embodiment;

FIGS. 6 to 10 are diagrammatic views of means for conveying a fiber placement machine for conveying a fiber from the storage means to a head according to other embodiments;

- Figure 11 is a schematic perspective view of conveying means according to the invention for a fiber application machine comprising a movable head in two orthogonal directions; and,

- Figure 12 is a partial cross-sectional view of Figure 11 at the holding sheath. Figures 1 to 3 illustrate the routing means according to the invention for routing a fiber in a fiber placement machine, as described for example in the patent document WO2008132299. The placement machine comprises a displacement system formed for example of a poly-articulated arm, of the six-axis robot type, mounted to move on a linear axis, a placement head mounted on the end wrist of the poly-articulated arm, fiber storage means, and routing means for conveying fibers from said storage means to the head. The head, diagrammatically shown as 1 in FIG. 2, comprises, in known manner, an application roll adapted to come into contact with a mold for applying a strip formed of a plurality of fibers.

The machine is intended for the application of flat fibers, for example carbon fiber type F, packaged in the form of coils. The storage means are formed of a creel, schematically represented under reference 2 in Figure 2, to receive the coils. Each coil is mounted on a mandrel of the creel, advantageously motorized or equipped with a closed loop automatic braking system according to the tension of the fiber. The creel is also mounted on a follower carriage, mounted on the linear axis and mechanically connected to the carriage carrying the robot.

For each fiber F, the conveying means comprise two endless belts 3 and 4, also called endless belts or straps, each forming a closed loop, extending from the creel to the head, and between which the unrolled fiber passes from a coil.

A first endless belt 3 is mounted between one of the first upstream return means, mounted on the creel 2, and formed of an upstream pulley 38, and first downstream return means mounted on the head 1 and formed of a pulley. downstream 39. A second endless belt 4 is mounted between second upstream return means mounted on the creel 2, formed of an upstream pulley 48, and second downstream return means, mounted on the head 1, and formed of A downstream pulley 49. The upstream pulleys 38, 48 are here mounted idler about parallel axes Al, A2 of rotation, and the downstream pulleys 39, 49 are mounted idle about axes A3, A4 parallel rotation. Each endless band 3, 4 has a strand said outer or return 31, 41, and a strand, said inner or go 32, 42 which extend between its pulleys downstream and upstream. The strands go 32, 42 strips are arranged vis-à-vis and are substantially parallel to each other. The unwinding fiber of the spool passes between the two strands going endless belts. The upstream pulleys are arranged symmetrically on either side of a plane of symmetry, so that at the output of the upstream pulleys, the forward strands are arranged vis-a-vis, but without being pinched between the two upstream pulleys. .

The forward strands 32, 42 pass into the internal passage of a first flexible conveying tube, said main 51, extending from the creel 2 to the head 1. The main tube has a rectangular cross-section wall, with two small sides 511a and two long sides 511b. The wall has a substantially planar inner surface and outer surface.

The return strands 31, 41 each pass through the internal passage of a so-called secondary flexible conveying tube 52, 53, extending from the creel to the head. Each secondary tube has a wall, of rectangular cross section, inner and outer surfaces substantially flat, for example identical to that of the main tube, with two small sides 521a, 531a and two long sides 521b, 531b.

The main tube 51 and the secondary tubes 52, 53 are placed in a so-called flexible holding tube 54, the main tube being positioned between the two secondary tubes. A flexible stiffening blade 55, 56, also called foil, is interposed between the main tube and each secondary tube. The flexible blades are metallic and also extend from the creel to the head. The holding tube is here a corrugated tube, of substantially rectangular section, with outer rings projecting outwardly of the annular tube and inner rings projecting inwardly of the annular tube. The holding tube extends over most of the conveying tubes. The holding tube keeps the flexible blades 55, 56 and the conveying tubes 51, 52, 53 flat against each other, the blades substantially parallel to the outer surfaces of the long sides 511b, 521b, 531b of the tubes. routing, while permitting relative longitudinal sliding of the flexible blades and conveying tubes relative to the other. The flexible blades 55, 56 have a width less than or equal to that of a long side, preferably less. The dimensions of the holding tube are defined so as to allow a slight relative transverse displacement of the flexible blades with respect to the routing tubes, as well as a relative displacement in rotation of the blades with respect to the conveying tubes, but limited to a few degrees, the blades remaining positioned between the long sides of the routing tubes.

The metal blades prohibit transverse bending of the main tube and the secondary tubes in the plane of the blades, but allows longitudinal bending of the conveying tubes in a direction perpendicular to the plane of the blade, as well as torsions of the conveying tubes.

For each fiber F, the conveying means comprise a pair of endless belts 3, 4, a holding tube 54 in which are placed a main tube 51 for the passage of the forward strands 32, 42 and a fiber, two secondary tubes 52, 53 for the passage of the return strands, and two flexible blades 55, 56. At the creel, the upstream pulleys 38 of the first, endless belts 3 are mounted idle about the same axis of rotation Al, and the pulleys at 48 of the second endless belts 4 are mounted idle about the same axis of rotation A2. Figures 1 and 2 are schematic views of the means for conveying a fiber. In practice, the routing tubes 51, 52, 53 are curved and have a length and flexibility sufficient to not limit the movements of the robot. During movements of the robot for fiber placement operations, the flexible tubes will deform by bending perpendicularly to the plane of the blade and / or twist, so that the strands go endless belts and the fiber F, as well as the return strands, stay flat, parallel to the long sides of the delivery tubes and flexible blades.

The holding tubes are gathered in a bundle, and can be placed in the internal passage of a flexible sheath, as described in patent WO2010 / 049424. This sheath is optionally cooled by cooling means placed in the cabinet of the creel, able to inject a cold gas into said internal passage of said sheath to cool and maintain the fibers at a low temperature, at which the fibers remain low tack.

The routing tubes of each fiber are fixed at the end to the creel and the head respectively by upstream and downstream fastening systems respectively shown in Figure 2, schematically, under the references 21 and 11. To allow longitudinal displacement relative to each other between the conveying tubes and the flexible blades, each conveying tube is assembled in a fixed manner, namely fixed without freedom of movement, by its end portion to the upstream fastening system 21, and assembled in a movable manner. longitudinal translation, namely fixed with a freedom of longitudinal displacement, by its other end portion to the downstream fastening system 11. One of the associated blades is fixedly assembled by its end portions to the upstream and downstream fastening systems. The other flexible blade is fixedly assembled by an end portion to the upstream fastening system 21, and movably in longitudinal translation by its other end portion to the downstream fastening system 11.

On the side of the creel, the fiber is engaged substantially parallel to the two strands go, according to the plane of symmetry on either side of which are arranged the upstream pulleys.

The head comprises in known manner guide means for guiding the fibers entering the head to the roll in the form of a band. These guide means are arranged so that each fiber exiting the downstream pulleys 39, 49 is disposed, substantially parallel to the forward strands, in the plane of symmetry on either side of which are disposed the two downstream pulleys.

The head conventionally comprises cutting means (not shown) capable of cutting, preferably individually, the fibers upstream of the application roller relative to the direction of travel of the fibers. Said cutting means comprise blades actuated by actuating systems between a rest position and an active cutting position. The blades optionally abut against counter-tools in their active cutting position.

The head further comprises rerouting means (not shown) arranged upstream of the cutting means, acting directly on the fibers, to reroute each fiber that has just been cut in order to be able to stop and resume the application of a band at any time, as well as to choose the width of the band. These rerouting means comprise counter rollers actuated by actuating systems between a rest position and an active position for pressing the fibers against at least one drive roller.

The head further comprises locking means arranged upstream of the cutting means, capable of blocking, preferably individually, the fibers that have just been cut. Said locking means comprise locking pads actuated by actuating systems between a rest position and an active locking position.

During draping, the fiber passes between the two strands go and drives the latter two, substantially without sliding. The endless belts 3, 4 are mounted on their pulleys upstream and downstream in an unstretched manner, so that a soft strand is formed on the side of the downstream pulleys, as illustrated in FIGS. 1 and 2. This assembly is not tensioned. allows to limit the wear of endless belts.

For example, the endless belts 3, 4 are made of a polymer material such as a polyester, a composite material, for example formed of carbon fibers and thermoplastic resin, such as a PEEK resin, or metal, and preferably have a width greater than that of the fiber to be conveyed. The routing tubes 51, 52, 53 are for example made of a polymeric material, such as a high-density polyethylene (HDPE) natural, comprising an antistatic adjuvant. The flexible holding tubes are made of a polymeric material, such as a polyurethane or a polyamide.

FIG. 4 illustrates an alternative embodiment of means for conveying a fiber, in which the downstream pulleys 139, 149 constitute means for rerouting the fiber.

On the creel side 102, the upstream pulleys 138, 238 are of tensioning pulley type, as illustrated by the arrows referenced F1, so that the endless belts 103, 104 are mounted taut on their upstream and downstream pulleys. For each pair of endless belts, the downstream pulley 139 of the first endless belt 103 is mounted at the end of the rod of a pneumatic cylinder said rerouting, as schematically illustrated by the arrow F2, to be moved between a rest position in which said downstream pulley 139 is spaced from the downstream pulley 149 of the second endless belt 104, and a active position in which the downstream pulley 139 comes to press its endless belt 103 against the other endless belt 104, and thus pinch the fiber between the two bands. The downstream pulley 149 of the second endless belt is adapted to be rotated by a motor, as illustrated by the arrow F3. The pulleys downstream of the second endless belts are integral with the same axis which is rotated by a motor. To convey a fiber from the creel to the roller, or to reroute the fiber after a cutting operation performed for example by an integrated cutting system in the head 101, the downstream pulley 139 is brought into the active position to clamp the fiber between the two endless belts, so as to drive the fiber via the downstream pulley 149 driven in rotation. If the ram for rerouting a fiber is in the rest position, the second endless belt slips on its downstream pulley 149 driven in rotation

In another variant, the upstream return pulleys are means of rerouting. The downstream pulleys are idle pulleys, while one of the upstream pulleys is movable via a re-routing cylinder towards the other upstream pulley which is motorized. The re-routing system is thus deported from the head to the creel, which simplifies the design of the head, and reduces its size.

FIG. 5 illustrates an alternative embodiment in which the upstream pulleys 238, 248 are motorized and form a voltage limiter system for limiting, at the level of the application roller, the call voltage of the fibers resulting from the tension of the bands without end induced by the friction of endless belts in their conveying tubes. The endless belts 203, 204 are non-tensioned on their upstream and downstream pulleys. During draping, the traction exerted on the fiber on the side of the head 201 creates soft strands on the side of the downstream pulleys and strands stretched on the side of the upstream pulleys. The endless belts are clamped against the upstream motorized pulleys 238, 239 and are thereby rotated, thereby driving the fiber. The call voltage of the fibers at roll level is thus substantially reduced, or substantially zero. The downstream pulleys of the pairs of endless belts are mounted integral with axes A1, A2 which are rotated by a motor, so that their peripheral speed is greater, for example by 30% at the speed of travel of the fiber. faster during draping. When the traction exerted on the fiber decreases, the slack is split on both sides, the endless belts are less tight against the downstream pulleys and are in sliding contact with the latter. The endless belts are no longer driven positively by the downstream pulleys. As a variant, only one of the two upstream pulleys is rotated.

FIG. 6 illustrates an alternative embodiment in which the head 301 is equipped with rerouting means 306 acting on the upstream strands 332, 342 between which the fiber F is positioned, as well as locking means 307 also acting on said forward strands.

For each fiber, the conveying means comprise, as before, two endless belts 303, 304 each mounted between an upstream pulley 338, 339 and a downstream pulley 348, 349, a main tube 351 in which the forward strands 332, 342 pass. endless belts and the fiber to be conveyed, and secondary tubes 352, 353 in which the return strands of the endless belts pass.

The main tube 351 and the secondary tubes 352, 353 may also be placed in the same annular tube (not shown), one or more flexible stiffening blades may further be interposed between said tubes. The tubes are fixed as previously to upstream and downstream fastening systems 311, 312.

The upstream pulleys 338, 348 are arranged in or against the cabinet of the creel in which are placed the bobbins B of fibers. The upstream pulleys 338, 348 are also motorized and form a voltage limiter system, as in the variant of FIG.

For each fiber, the rerouting means 306, of a type known per se, comprise a counter-roller and a drive roller arranged opposite each other, on either side of the strands, at the outlet of the main tube. and upstream of the downstream pulleys. The counter-roller is mounted at the end of the rod of a pneumatic cylinder to be actuated between a rest position and an active position to press the two strands. to go against each other, and against a training roller. The drive roller is rotated by a motor and can be associated with several counter rollers for the rerouting of several fibers independently of one another.

For each fiber, the blocking means 307 comprise a blocking stud, mounted at the end of a pneumatic cylinder, and a locking counter-tool, the pad and the counter-tool being arranged opposite each other, on both sides of the strands go.

The blocking means and the rerouting means do not come into direct contact with the fibers, which limits the risk of deterioration of fibers during their blocking and re-aging.

FIG. 7 illustrates another variant embodiment comprising, as before, a first pair of endless belts 403a, 404a each mounted between an upstream pulley 438a, 448a at the level of the creel 402 and a downstream pulley 439a, 449a at the head 401. The machine further comprises a second pair of endless belts 403b, 404b disposed in the creel 402 between the upstream pulleys 438a, 448a of the first pair of endless belts and the reel B. These endless belts 403b, 404b are each mounted between an upstream pulley 438b, 448b and a downstream pulley 439b, 449b. This second pair of endless belts is associated with a voltage limiter system 408 acting on its forward strands, so that the fiber entering the first pair of endless belts has a reduced voltage.

This voltage limiter system, the principle of which is described in document WO2006 / 092514, comprises a set of motorized cylinders 481, rotatably mounted parallel to one another, on which the forward strands of the endless pairs of bands pass without going around it. . The cylinders are rotated by a single motor. The fiber F, unwound from a bobbin B of the creel passes between the forward strands 432b, 442b of the two endless belts, the fiber being initially introduced between the two upstream pulleys 438b, 448b. The cylinders are driven at a continuously regulated speed to be substantially greater at any time, for example by 30%, at the speed of travel of the fastest fiber. As a variant, the rolls are driven at a constant speed, as soon as the machine is started up, which will be determined according to the planned draping sequences.

The cylinders may include annular grooves for receiving the forward strands of endless belt pairs, the forward strands coming directly into contact with the cylinders. Alternatively, to limit the wear of the endless belts on the rollers, belts may be mounted around each cylinder 481 so that a belt is interposed between the forward and the cylinder ends, each belt being adapted to adhering to a strand go and being driven more or less by the cylinder depending on the pressure exerted by the strands go on the belt, said pressure being proportional to the call voltage on the fiber. Each belt may be looped on a sliding path using crescent shaped discs as described in the aforementioned patent document. When the fiber is stopped, the pressure exerted by the strands on a belt is zero, the belt is then in sliding contact with the cylinder. As the fiber advances, the strands go to exert a pressure on the belt such that the belt is then driven by the cylinder, with a slippage between the belt and the cylinder proportional to the pressure exerted by the forward strands. The relative velocity between the cylinder and the belt is therefore proportional to the pressure exerted, the relative velocity between the belt and the strands being zero or very low.

Compared to the voltage limiter system described in the aforementioned document, the fibers are no longer in direct contact with the rolls or the belts. The fibers are isolated between the strands go, without sliding, and are thus protected from any deterioration.

The first pair of endless belts 403a, 404a is identical to that of the variant of FIG. 6. The upstream pulleys 438a, 448a are also motorized and form a tension limiter system. The fiber exiting the downstream pulleys 439b, 449b of the first pair of endless belts passes between the upstream pulleys to be conveyed to the head between the forward strands 442a, 432a. Advantageously, the same motor serves to drive the upstream pulleys 448a, 438a of the first pair of endless belts and the cylinders 481 of the voltage limiter system. The head 401 is also equipped with means of rerouting 406 and locking means 407 acting on the strands go endless bands of the first pair.

The voltage limiting system 408 which limits the voltage of the fiber entering the first pair of endless belts, combined with the motorized upstream pulleys of the first pair which limit the tension in the endless bands of the first pair, reduce the call voltage of the fiber at the head.

FIG. 8 illustrates an alternative embodiment that differs from the variant of FIG. 7 in that the rerouting means 506 are offset in the creel 502 and act on the return strand 531a of the one 503a of the endless belts 504a. , 503a of the first pair.

For each fiber, the rerouting means 506 comprise a counter-roller and a drive roller arranged facing each other, on either side of the return strand 531a of the strip 503a, at the outlet of the secondary tube 553 and upstream of the upstream pulley 538a. The counter-roller is mounted at the end of the rod of a pneumatic cylinder to be actuated by a cylinder-type actuating system between a rest position and an active position to press the return strand against a drive roller. . At the output of the secondary tube, the return strand passes on two intermediate return pulleys 536a, 537a, before passing on the upstream pulley 538a. The counter-roller and the associated drive roller act on the portion of the return strand extending between the two intermediate pulleys.

To ensure a better accuracy in the rerouting, a tensioning system 509 is able to act on said return strand 531a between the rerouting means 506 and the upstream pulley 538a to tension the return strand between the downstream pulley 539a and the rerouting means 506 when the blocking means 507 block the forward strands 532a, 542a and the fiber F. This tensioning system comprises a clamping system comprising two members 591, 592 between which the return strand 531a passes. The two members are operable between an inactive position, in which the members are spaced apart from each other, and an active clamping position in which the two members are able to clamp between them the return strand. The clamping system is mounted mobile in translation, parallel to the return strand and is adapted to be operated by a displacement system 593, for example of the jack type pneumatic, to stretch the strand back. To reroute a fiber just cut through cutting means of the head, and blocked via the locking means, the members of the clamping system are operated in the active position to pinch the return strand, and the cylinder 593 is actuated to stretch the strand back. The counter-roller is maneuvered in active position and simultaneously, the organs are maneuvered in the inactive position.

FIG. 9 illustrates another variant of embodiment which differs from that of FIG. 7 in that it comprises a single pair of endless belts 603, 604, including the upstream pulleys 638, 648 and the downstream pulleys 639, 349. are mounted idle about axes, without drive, and that a voltage limiter system 608, similar to that described with reference to Figure 7, acts on the forward strands 632, 642 endless bands, èn output pulleys upstream 638, 648, and before entering the main tube 651.

Furthermore, diverting means 606 and an associated tensioning system 609 act on the return strand 631 of one of the two endless belts 603 at the outlet of the secondary tube 653 and upstream of the upstream pulley 638.

In this embodiment, the re-routing means 606 comprise, for each fiber,

an endless belt 661, also called a rerouting conveyor, having a so-called active strand 661a, which extends parallel to the return bristle 631 of the endless belt 603, and

a clamping system 662 comprising two members 663 664 between which the active strand 661a of the redirecting conveyor passes and the return strand 631 of the endless band.

The clamping system is mounted movable in translation, parallel to the active strand 661a, between an initial position and an end position. The two members are operable between an inactive position, in which the members are spaced from each other and an active clamping position in which the two members are able to clamp between them the active strand and the return strand. The conveyor is preferably driven continuously.

During draping, the members 662, 663 are in the inactive position, the return strand extends parallel to the active strand of the conveyor, without being in contact with the latter. The clamping system is in the initial position shown in Figure 9.

To reroute a fiber, the tensioning system 609 is actuated to tension the return strand, the locking means 607 being in the active blocking position. The members 662, 663 are maneuvers in the active position to clamp the return strand and the active strand and, simultaneously, the clamping members of the tensioning system are operated to their inactive position and the locking means are returned to the rest position. The conveyor drives the return strand and thus redirects the fiber placed between the strands to go. When the tightening system reaches its end position, the organs are maneuvered in the inactive position. A jack system 665 is then actuated to return the clamping system to its initial position. The stroke between the initial position and the end position corresponds, for example, to the distance for the rerouting of a fiber from the roller cutting system.

According to one embodiment, the two members 662, 663 are mounted on a support slidably mounted on a rail parallel to the active strand, one of the members is fixedly mounted on this support while the other is a movable member. The members are for example formed of a fixed abutment and a diaphragm cylinder optionally equipped with a pressure plate.

The machine comprises a pair of endless fiber belts, and a clamping system and a pair of endless belt re-routing conveyor. Rerouting conveyors were driven by one engine. Alternatively, the machine comprises a re-routing conveyor for a plurality of endless belts, and a clamping system for each endless belt.

According to an alternative embodiment, the cutting means are arranged in the creel, upstream of the upstream pulleys. The rerouting system can be used to route several fiber sections arranged one behind the other between the two forward strands.

The routing via the pair of endless belts also makes it possible to convey up to the head two successive fibers edge to edge, or overlapping, thereby allowing reel changes without complex splicing operations. FIG. 10 illustrates an embodiment variant in which for each fiber, the conveyor means comprise a single pair of endless belts 703, 704, each endless belt is mounted between an upstream pulley 738, 748 at the level of the creel 702, and a downstream pulley 739, 749 at the head 701. As previously described, the forward strands 732, 742 pass through a main tube 751 and the return strands 731, 741 each pass through a secondary tube 752, 753.

The machine comprises a tension limiter system 708, placed in an intermediate unit 707, and acting on the strands going between the creel and the head. To do this, between the head and the intermediate unit, the forward and return strands pass in a first section 751a of the main tube and first sections 752a, 753a of secondary tubes, these first sections 751a, 752a, 753a being assembled. at the end on the one hand to a downstream fastening system 711 of the head and on the other hand an upstream fastening system 771a of the intermediate unit. Between the intermediate unit and the creel, the forward and return strands pass into a second section 751b of main tube and second sections 752b, 753b of secondary tubes, these second sections being assembled at the end on the one hand to a system Upstream attachment 771b of the intermediate unit and secondly an upstream fastening system 721 of the creel.

The intermediate unit 707 is disposed between the creel and the head, in an intermediate position, fixed or movable relative to the creel and / or the head. For example, the head is mounted on the wrist of a robot mounted on a linear axis, the intermediate unit is mounted on the base of the robot and the creel is positioned fixedly relative to the ground, close of the rail. The first sections of main and secondary tubes are collected and placed in a sheath extending from the head to the intermediate unit. The second sections of main and secondary tubes pass through a cable chain, which extends along the rail, and which optionally contains the electric and pneumatic cables for controlling the robot and the head.

The forward strands 732, 742 leaving the second section 751b of the main tube pass between the cylinders 781 of the voltage limiter system, before entering the first section 751a of the main tube. The intermediate unit includes redirection means 706 and a tensioning system 709 associated, arranged between the first section and the second section of a secondary tube, and acting on the return strand 731 of one of the strips leaving a first section of secondary tube, before entering the second section of secondary tube. As illustrated in FIG. 10, the other return strand 741 may be placed in a continuous secondary tube extending from the head to the creel, the first and second sections then extending between the upstream and downstream attachment systems of the intermediate unit, to join and form said continuous secondary tube.

FIGS. 11 and 12 illustrate means for conveying a fiber application machine comprising, as before, for each fiber, a pair of endless belts 803, 804, each endless belt being mounted between an upstream pulley 838, 848 mounted on the creel and a pulley downstream 839, 849 mounted on the head. The forward strands 832, 842 pass through main tubes 851 and back strands 831, 841 into secondary tubes 852, 853.

The main tubes are in the form of a sheet of main tubes connected in pairs by their small sides. Two plies of similar secondary tubes are used for the return strands of the two endless belts.

The machine is planned here to drape a wide band of 32 wicks. The upstream pulleys of the pairs of endless belts are rotatably mounted around the axis A1, A2, and the downstream pulleys are mounted around axis of rotation A3 and A4. In this embodiment, the axes A1 to A4 remain substantially parallel to each other during draping operations. The movement system of the machine allows a relative movement of the head relative to the creel, in directions Z and X which are perpendicular to each other and to the axes Al-A4.

The sheet of main tubes is placed between the two plies of secondary tubes by interposing large blades 855, 856 flexible metal. The assembly is placed in a holding sheath 854.

Although the invention has been described in connection with various particular embodiments, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention.

Claims

A fiber application machine comprising a fiber application head (1, 201, 301, 401, 501, 601, 701), fiber storage means (2, 202, 302, 402, 502, 602). , 702) arranged at a distance from said head, and routing means for conveying the fibers of said storage means to the application head, characterized in that said conveying means comprise at least one endless band (3, 4, 103, 104, 203, 204, 303, 304, 403a, 403b, 404a, 404b, 603, 604, 703, 704, 803, 804), extending between the head and the fiber storage means, mounted between an upstream return system and a downstream return system, said endless band comprising a forward strand against which a fiber is able to come into contact without sliding.

2. Machine according to claim 1, characterized in that said conveying means comprise at least one pair of endless belts extending between the head and the fiber storage means, of which

a first endless band (3; 103; 203; 303; 403a; 403b;

603; 703; 803) mounted between first upstream return means (38, 138, 238, 338, 438a, 438b, 638, 738), and first downstream return means (39, 139, 239, 339, 439a, 439b, 639, 739),

a second endless band (4; 104; 204; 304; 404a, 404b;

604; 704; 804) mounted between second upstream return means (48, 148, 248, 348, 448a, 448b, 648, 748), and second downstream return means (49, 149, 249, 349, 449a, 449b, 649, 749),

the first endless band and the second endless band having forward strands (32, 42; 332, 342; 432a, 442a, 432b, 442b; 632, 642; 732, 742; 832, 842) parallel to each other and arranged in a screwed configuration; - Opposite, able to receive between them, without sliding, at least one fiber (F).

3. Machine according to claim 1 or 2, characterized in that the downstream return system is mounted on the head.

4. Machine according to one of claims 1 to 3, characterized in that, or the strands go (32, 42; 332, 342; 432a, 442a 432b, 442b; 632, 642; 732, 742; 832, 842; ) pass through a flexible main tube (51, 351, 651, 751a, 751b, 851).

5. Machine according to claim 4, characterized in that the return strand or strands (31, 331, 431a, 431b, 631, 731, 831, 41, 341, 441a, 441b, 641, 741, 841) each pass into a secondary tube (52, 352, 752a, 752b, 852; 53, 353, 753a, 753b, 853) flexible.

6. Machine according to claims 4 and 5, characterized in that the main tube (51, 351, 651, 751a, 751b, 851) and the secondary tube or tubes are placed in a flexible holding tube (54, 854), so that said holding tube holds the main tube and the secondary tube or tubes against each other, while allowing relative longitudinal movement of the main tube and the secondary tube or tubes relative to one another.

7. Machine according to one of claims 4 to 6, characterized in that the conveying means comprise at least one blade (55, 56; 855, 856) longitudinal flexible, said flexible blade being disposed substantially parallel to the transport plane fiber received in the inner passage of the main tube (51, 851).

8. Machine according to one of claims 1 to 7, for the application of a strip formed of several fibers, characterized in that the conveying means are capable of conveying a plurality of fibers, and comprise an endless band or a pair of endless bands by fiber.

9. Machined according to one of claims 1 to 8, characterized in that it comprises means of redirection (139, 149; 306; 406; 506; 606; 706) able to act on at least one strand go and / or a return strand of an endless belt for driving said strand, and thereby driving the fiber into contact with said endless belt.

10. Machine according to claims 2, 3 and 9, characterized in that said redirecting means (138, 148; 306, 406) are arranged in the head, and act on the two strands go endless belts.

11. Machine according to claim 9, characterized in that said rerouting means (139, 149; 306; 406; 506; 606; 706) are arranged at a distance from the head, on the side of the upstream return system, and act on the strand back of an endless band.

12. Machine according to one of claims 1 to 11 in combination with claim 2, characterized in that the return system downstream is placed on the head, the machine comprises locking means (307, 407, 507) capable of clamping the forward strands (332, 432; 432a, 442a; 532a, 542a) to block the fiber placed between them.

13. Machine according to one of claims 1 to 12, characterized in that it comprises a voltage limiting system (408; 608; 708) comprising at least one cylinder (238, 248; 338, 348; 481, 781). over which the endless belt passes, and drive means for rotating said cylinder so that the peripheral speed of the cylinder is greater than the speed of travel of the fiber at the head.

14. Machine according to claim 13, characterized in that the upstream return system (238, 248; 338, 348) forms the cylinder or cylinders of said voltage limiter system.

15. Machine according to one of claims 1 to 14, characterized in that it comprises a displacement system for moving the fiber application head, said displacement system being adapted to perform a relative movement of said head relative to said storage means.

16. Machine according to one of claims 1 to 15, characterized in that the downstream return system is placed in the head, the machine comprises cutting means adapted to cut each fiber upstream of the upstream return system.

17. Machine according to one of claims 1 to 16, characterized in that it comprises heating means or strands go.

18. Process for producing a preform comprising

the routing of fibers from storage means to a fiber application head, said storage means being disposed at a distance from said head, and

the application of said fibers by the application head to a tool by relative displacement of the head relative to the tooling, characterized in that, for the routing of each fiber, said fiber is brought into contact, substantially without slip, with the strand go from at least one band.

19. A method of producing a composite material part characterized in that it comprises a step of hardening a preform obtained according to claim 18, after a possible step of adding resin to the preform.