EP4551745A1 - Braiding machine with a reserve zone - Google Patents

Abstract

The invention relates to a braiding machine comprising: - a plurality of yarn feed spindles (30) movable along a guide path (100) so as to participate in the braiding, and - a reserve zone (20) able to receive at least one spindle (30) such that its participation in the braiding is interrupted.

Description

Description

Title of the invention: Braiding machine with a reserve zone

Technical area

The present invention relates to braiding machines allowing the production of braided structures, and more particularly braided tubular structures having strong variations in section.

Prior art

A braiding machine conventionally comprises a plate having circuits, called guide paths, which intersect each other and along which yarn supply spindles connected to a drawing point of the machine are moved. These thread supply spindles therefore intersect regularly to create a braid. Generally speaking, the formation of the braid can be carried out on a form, called a conformation mandrel, which moves during the formation of said braid: we then speak of “over-braiding”. The movement of the spindles along the guide paths is conventionally carried out by means of notched wheels driven in rotation and preferably arranged in one or more concentric circles. Such braiding machines are for example described in documents FR 2 804 133 and US 8 347 772.

When we wish to manufacture a braided structure having strong variations in section with a machine of the prior art, we note that the braided structure obtained does not have uniform braiding. Indeed, in the areas of the braid having a large section, the density of wires is lower or even insufficient, or the angles between the braided wires are greater, in comparison with the areas of the braid of smaller section.

Presentation of the invention

The present invention aims to remedy the aforementioned drawbacks by proposing a braiding machine capable of producing a uniform braided structure despite strong variations in section. To this end, according to a first aspect of the invention, the invention proposes a braiding machine comprising: - a plurality of wire feed spindles connected to guide supports and movable along a guide path so as to participate in braiding, all or part of the spindles being integral with a positioning element cooperating with a support corresponding and removable guide relative to the latter,

- a plurality of reserve supports located outside the guide path, said reserve supports being able to receive wire feed spindles placed in reserve so as to interrupt their participation in braiding, the positioning elements being able to cooperate with the reserve media to achieve this reserve.

Thus, the use of spindles capable of cooperating with movable guide supports along the guide path makes it possible to easily remove or add spindles to the braiding, without requiring complex operations such as dismantling the plate of the braiding machine.

Such a system of cooperation between the positioning elements and the guide supports therefore makes it possible to easily vary the number of wire supply spindles participating in the braiding of the braided structure. Thus, the number of spindles participating in the braiding can be adapted to the section of the structure to be braided in order to obtain a constant thread density and angle values between the threads despite variations in section.

Thus, when it is desired to reduce the section of the braided structure, spindles are removed from the guide path in order to interrupt their participation in braiding, by separating the positioning elements of said spindles from the guide supports. The number of braided wires is therefore reduced, which makes it possible to avoid a notable increase in the density of wires, or even an undesired reduction in the angles between the braided wires, at the level of the area of lower section. On the contrary, when it is desired to increase the section of the braided structure, spindles are added to the main guide path, by mounting the positioning elements of said spindles with the guide supports present on the guide path. We therefore increase the number of braided wires, which makes it possible to avoid a notable reduction in the density of wires, or even an undesired increase in the angles between the braided wires, at the level of the zone of weakest section. The braiding weave therefore remains identical and uniform over the entire braided structure thus obtained.

The use of reserve supports makes it possible to easily store the spindles in a reserve area, in particular the spindles which have been removed from the guide path in order to interrupt their participation in the braiding, and/or the spindles which are intended to be added on the guide path to participate in braiding.

According to a particular embodiment of the invention, the machine comprises a reserve support drive system capable of driving at least part of the reserve supports circumferentially to the guide path.

The reserve supports go around the outer edge of the guide path, or go around the inner edge of the guide path.

The use of a reserve zone comprising at least one movable part in rotation circumferentially to the guide path makes it possible to limit the appearance of singularities in the braiding. Indeed, when a spindle has just been removed from the guide path in order to interrupt participation in the braiding of the thread coming from said spindle, the thread coming from said spindle is still in the process of intertwining. When the thread is being intertwined, it is neither braided and tightened with the other threads, nor free. There is therefore a transition stage in which the thread no longer participates in the braiding, but is still in the process of intertwining, so that part of the thread is completely braided and tightened with the other threads, part of the thread is being intertwined and part of the thread is free. This transition stage ends when the part of the thread which was being intertwined is completely braided and tightened with the other threads, that is to say that the thread only includes a completely braided and tightened part, and a free part that is not braided and not intertwined.

If the spindle removed from the guide path is directly positioned on a fixed reserve support in relation to the movable guide supports, the wire coming from said spindle is suddenly stopped while it may be in the process of intertwining, this which can lead to unwanted tensions in the threads or to singularities in the braiding. In order to accompany the thread during the transition stage, that is to say when it is still in the process of intertwining and no longer participates in braiding, the spindle from which said thread comes can be positioned on a mobile reserve support. Said mobile reserve support thus makes it possible to extend the movement of the spindle in the clockwise or counterclockwise direction, until at least the end of the transition stage. When the transition step is completed, the movement of the movable reserve support can be interrupted, the spindle can be moved to a fixed part of the reserve zone and/or the thread coming from said spindle can be cut.

According to another particular embodiment of the invention, the drive system for the reserve supports comprises at least a first ring circumferential to the guide path and capable of rotating in a first direction of rotation and at least a second ring circumferential to the guide path and capable of rotating in a second direction of rotation opposite to the first direction of rotation, each first or second crown carrying one or more reserve supports.

The first and second rings surround the outer edge of the guide path, or go around the inner edge of the guide path.

Thus, it is possible to simultaneously support in their transition stage threads from spindles which rotated clockwise on the guide path and threads from spindles which rotated counterclockwise.

According to another particular embodiment of the invention, the reserve supports are present around the guide path.

By placing the reserve zone, and any circumferential reserve rings, on the periphery of the guide path, access to the spindles present in the reserve zone is facilitated.

According to another particular embodiment of the invention, the machine further comprises a shaping mandrel on which the braiding is intended to be carried out.

The presence of a shaping mandrel makes it easier to braid the structure, the shape of the shaping mandrel providing support on and around which the wires can be braided with the desired section. According to another particular embodiment of the invention, the machine comprises an overall drive system comprising the reserve support drive system and a guide support drive system, the overall drive system being configured so that the angular speed of at least part of the reserve supports is a function of the angular speed of at least part of the guide supports so that the movement of at least part of the reserve supports accompanies the movement of 'at least part of the guide supports.

According to another particular embodiment of the invention, the overall drive system comprises a transmission system configured to transmit the movement of a guide support drive system to the reserve support drive system.

Preferably, the drive system for the reserve supports is a pinion/rack system. Preferably, the guide support drive system is a system of notched wheels driven in rotation by a gear train. Preferably, the transmission system is a belt system connecting the gear train of the guide support drive system to the pinion/rack system of the reserve support drive system. Indeed, this overall drive system has the advantage of being robust and allowing high braiding speeds.

According to another particular embodiment of the invention, the machine further comprises a robotic arm configured to move at least one spindle between a guide support and a reserve support.

According to another particular embodiment of the invention, the machine further comprises a cutting device configured to cut a wire coming from a feed spindle whose positioning element cooperates with a reserve support.

The invention also relates to a method for braiding a braided structure comprising a first zone having a first section and a second zone having a second section different from the first section, the method implementing a machine according to the first aspect of the invention and comprising:

- braiding the first zone of the braided structure with a first number of wire feed spindles movable along the guide path, and

- braiding the second zone of the braided structure with a second number of wire feed spindles movable along the guide path, the second number of spindles being different from the first number of spindles thanks to the movement of spindles between the supports guide and the reserve supports by cooperation of the positioning element of said spindles moved with the guide or reserve supports.

The invention also proposes, according to a second aspect of the invention, a braiding machine comprising:

- a plurality of wire feed spindles movable along a main guide path so as to participate in braiding, characterized in that it further comprises:

- a reserve zone adjacent to the main guide path and comprising at least one secondary guide path capable of receiving at least one spindle and maintaining it in the reserve zone so as to interrupt its participation in braiding, each secondary guide path being associated with at least one switching element which is movable between a first position preventing communication between the main guide path and the secondary guide path, and a second position authorizing this communication and configured to allow a passage of at least a spindle between the main guide path and the secondary guide path.

The reserve area may be located on the outer edge side of the main guide path, or on the inner edge side of the main guide path. According to one example, the reserve zone can surround the outer edge of the main guide path, or go around its inner edge.

The presence of the reserve zone makes it possible to vary the number of thread supply spindles participating in the braiding of the braided structure. Thus, the number of spindles participating in the braiding can be adapted to the section of the structure to be braided in order to obtain constant thread density and angle values between the threads despite variations in section.

Thus, when it is desired to reduce the section of the braided structure, spindles are removed from the main guide path in order to interrupt their participation in braiding. The number of braided wires is therefore reduced, which makes it possible to avoid a notable increase in the density of wires, or even an undesired reduction in the angles between the braided wires, at the level of the area of lower section. On the contrary, when we wish to increase the section of the braided structure, we move spindles present in the reserve zone in order to add them to the main guide path. We therefore increase the number of braided wires, which makes it possible to avoid a notable reduction in the density of wires, or even an undesired increase in the angles between the braided wires, at the level of the zone of lower section. The braiding weave therefore remains identical and uniform over the entire braided structure thus obtained.

According to a particular embodiment of the invention, the machine further comprises a shaping mandrel on which the braiding is intended to be carried out.

The presence of a shaping mandrel makes it easier to braid the structure, the shape of the shaping mandrel providing support on and around which the wires can be braided with the desired section.

According to another particular embodiment of the invention, the reserve zone is formed by a plurality of reserve regions distributed along the main guide path, each reserve region comprising a secondary guide path separated from the secondary guide paths from other reserve regions.

According to another particular embodiment of the invention, the machine comprises a plurality of main notched wheels configured to be rotated in order to circulate the feed spindles along the main guide path, said machine further comprising one or more secondary notched wheels in the reserve zone, each secondary guide path in the reserve zone being associated with at least secondary notched wheel configured to be rotated in order to circulate at least one feed spindle along said secondary guide path.

According to another particular embodiment of the invention, the machine comprises at least one rotation decoupling system configured to make the rotation of at least one secondary notched wheel independent of the rotation of the main notched wheels.

According to another particular embodiment of the invention, at least part of the switching elements are movable in translation to move from the first to the second position.

According to another particular embodiment of the invention, at least part of the switching elements can rotate to move from the first to the second position.

According to another particular embodiment of the invention, the machine further comprises a control unit configured to actuate the switching element.

According to another particular embodiment of the invention, the machine further comprises a cutting device configured to cut a wire coming from a feed spindle present in the reserve zone.

The invention also relates to a method of braiding a braided structure comprising a first zone having a first section and a second zone having a second section different from the first section, the method using a machine according to the second aspect of the invention and comprising:

- braiding the first zone of the braided structure with a first number of movable wire feed spindles along the main guide path, and

- braiding the second zone of the braided structure with a second number of wire feed spindles movable along the main guide path, the second number of spindles being different from the first number of spindles thanks to the passage of spindles between the main guide path and the reserve zone by actuation of the switching element.

Brief description of the drawings [Fig. 1] Figure 1 is a three-dimensional view of a braiding machine according to the first aspect of the invention.

[Fig. 2] Figure 2 is a detail in top view of the braiding machine of Figure 1.

[Fig. 3] Figure 3 is an exploded schematic view of a spindle cooperating with a guide support.

[Fig. 4] Figure 4 is a schematic view of the operating mechanisms of the braiding machine of Figures 1 and 2.

[Fig. 5] Figure 5 is a schematic view of the machine of Figures 1 and 2 when braiding a portion of braid of large section.

[Fig. 6] Figure 6 is a schematic view of the machine of Figures 1 and 2 during braiding of a portion of braid of progressive section.

[Fig. 7] Figure 7 is a schematic view of the machine of Figures 1 and 2 when braiding a portion of braid of small section.

[Fig. 8] Figure 8 is a schematic view of a braiding machine according to the second aspect of the invention when braiding a part of braid of large section.

[Fig. 9] Figure 9 is a schematic view of the braiding machine of Figure 8 when braiding a part of braid of small section.

[Fig. 10] Figure 10 is a schematic view of a portion of the plate of the braiding machine of Figures 8 and 9 comprising notched wheels.

[Fig. 11] Figure 11 is a schematic view of a switching element movable in translation in its second position according to a first embodiment.

[Fig. 12] Figure 12 is a schematic view of a switching element movable in translation in its first position according to a second embodiment.

[Fig. 13A] Figure 13A is a schematic view of a switching element movable in translation in its second position according to a third embodiment. [Fig. 13B] Figure 13B is a schematic view of the switch element of Figure 13A in its first position.

[Fig. 14] Figure 14 is a schematic view of a rotating movable switch element according to a fourth embodiment.

[Fig. 15] Figure 15 is a schematic view of a rotating movable switch element according to a fifth embodiment.

[Fig. 16] Figure 16 is a schematic view of a rotating movable switch element according to a sixth embodiment.

Description of embodiments

A first aspect of the invention is presented in relation to Figures 1 to 7.

Figures 1 and 2 schematically illustrate an example of a braiding machine according to the first aspect of the invention making it possible to produce a braided structure.

The braiding machine comprises a plate 1 and a plurality of wire feed spindles 30. The plate 1 is preferably horizontal, in order to facilitate its maintenance and that of the wire feed spindles 30. However, we do not leave the framework of the invention if the plate 1 is vertical or inclined.

The plate 1 comprises a braiding zone 10. The braiding zone 10 comprises a guide path 100 and a plurality of guide supports 51 capable of cooperating with said guide path 100, and therefore capable of moving along the path guide 100. Preferably, the guide path 100 is machined in the mass of the plate 1 in the form of grooves, having for example a substantially rectangular section, open towards the outside, and inside which the supports move guide 51.

Each guide support 51 comprises a guide face 51a and a mounting face 51b opposite the guide face 51a. The guide face 51a is capable of cooperating with the guide path 100. In particular, the guide face 51a of the guide support 51 comprises a projecting relief configured to move at inside the groove of the guide path 100. Preferably, all the guide supports 51 present in the braiding zone 10 are identical.

Preferably, the braiding machine comprises a conforming mandrel 5, which is a shape on which the intertwined threads come to rest to form the tight braid. In this case, the braiding machine makes it possible to carry out so-called “over-braiding” processes. The braiding machine according to the invention is particularly interesting in the case where it is desired to produce a braid having significant variations in section, and more precisely a braid whose perimeter of the section varies significantly. Unless otherwise stated, the sections are taken perpendicular to a longitudinal axis of the braided structure. Consequently, the advantages provided by the braiding machine according to the invention are particularly remarkable when said braiding machine comprises a conforming mandrel 5 whose shape has strong variations in thickness.

The braiding machine further comprises at least one drawing point located at a distance from the plate 1, and to which the threads coming from the supply spindles 30 movable along the guide path 100 are connected.

The braiding machine also includes a reserve zone 20 circumferential to the braiding zone 10, which comprises a plurality of reserve supports 52. In the example illustrated in Figures 1 and 2, the reserve zone 20 is present around the outer edge of the braiding zone 10, which allows easier access to said reserve zone 20. However, we do not depart from the scope of the invention if the reserve zone 20 goes around the inner edge of the braiding zone braiding 10. Preferably, the reserve zone 20 is located in the same plane as the braiding zone 10. Preferably, the reserve zone 20 is adjacent to the guide path 100.

The reserve zone 20 is presented here in the form of several circumferential and concentric rings 21, 22, 23. Each crown 21, 22, 23 comprises at least one reserve support 52. Each reserve support 52 comprises a mounting face 52b. Preferably, all the reserve supports 52 present in the reserve zone 20 are identical. As illustrated in Figure 3, each wire feed spindle 30 comprises a holding portion 34 intended to accommodate a spool of wire, extended by a positioning element 35. The positioning element 35 is integral with the spindle 30. L the positioning element 35 is configured to cooperate with the guide supports 51 and with the reserve supports 52. In particular, the positioning element 35 comprises a mounting face 35b opposite the holding portion 34, which is configured to cooperate with the mounting face 51b of the guide supports 51 and with the mounting face 52b of the reserve supports 52.

In particular, the mounting face 35b of the positioning element 35 may comprise a groove, and the mounting faces 51b and 52b of the guide supports 51 and reserve 52 may comprise a projecting relief, the groove of the mounting face 35b of the positioning element 35 being configured to cooperate with the projecting relief of the mounting faces 51b and 52b of the guidance supports 51 and 52. The reverse is also possible.

Thus, each spindle 30 can be mounted on a guide support 51, by making the mounting face 35b of said spindle 30 cooperate with the mounting face 51b of said guide support 51, and can be mounted on a reserve support 52, in causing the mounting face 35b of said spindle 30 to cooperate with the mounting face 52b of said reserve support 52. Preferably, all the spindles 30 can be mounted on all the guide supports 51 and on all the reserve supports 52. Preferably , the mounting faces 51b of the guide supports 51 and the mounting faces 52b of the reserve supports 52 are identical.

The spindles 30 mounted on the guide supports 51 in the braiding zone 10 can participate in braiding, that is to say that the thread or threads coming from the bobbins of said spindles 30 mounted on the guide supports 51 can be braided. Thus, the spindles 30 mounted on the guide supports 51 are movable along the guide path 100.

The guide path 100 is configured to be traveled in a first direction of rotation, for example in the clockwise direction, by a first plurality of spindles 30 and in a second direction of rotation, for example in the counterclockwise direction, by a second plurality of bobbins 30 in order to carry out the braiding. Thus, a first plurality of guide supports 51 is configured to be movable at least in the clockwise direction and a second plurality of guide supports 51 is configured to be movable at least in the counterclockwise direction.

In the example illustrated in Figures 1 and 2, the guide path 100 comprises two sub-guide paths 110 and 120 which intersect regularly, the first sub-guide path 110 being configured to be traversed by the first plurality of guide supports 51 on which the first plurality of spindles 30 are mounted and the second sub-path 120 being configured to be traversed by the second plurality of guide supports 51 on which the second plurality of spindles 30 are mounted. of course not within the scope of the invention if the guide path comprises more than two sub-paths, for example if one wishes to produce a braided structure comprising several layers or having a complex binding weave, such as for example interlock braiding .

The braiding machine according to the invention comprises in a well-known manner a system for driving the guide supports 51. Preferably and in a well-known manner, the braiding zone 10 of the plate 1 comprises a plurality of notched wheels 11 configured to be rotated in order to circulate the wire feed spindles 30 along the guide path 100, as illustrated in Figures 1 and 2. Each notched wheel 11 preferably comprises four notches. The notched wheels 11 are preferably rotated in a well-known manner via gear trains controlled by one or more motors, the gear trains being preferably located on the face of the plate 1 opposite the face comprising the guide path 100 and the notched wheels 11. For example, the reserve area 20 does not include notched wheels, and the reserve supports 52 are not driven by notched wheels.

The braiding machine according to the invention preferably comprises a system for driving the reserve supports 52, capable of driving at least part of the reserve supports 52 circumferentially to the guide path 100. In the example illustrated in Figures 1 at 4, the rotational drive system of the reserve supports 20 comprises at least one circumferential ring 21, 22 movable in rotation circumferentially to the braiding zone 10, that is to say movable in rotation along the inner or outer edge of the guide path 100. The zone of reserve 20 further preferably comprises at least one fixed circumferential crown 23.

Preferably, the reserve zone 20 comprises at least a first circumferential ring 21 movable in a first direction of rotation, for example movable in the clockwise direction, and at least one second circumferential ring 22 movable in a second direction of rotation opposite to the first direction of rotation, for example movable counterclockwise.

The first circumferential ring(s) 21 movable in the clockwise direction can accompany the movement of the first plurality of guide supports 51 movable on the guide path 100 in the clockwise direction, and consequently the movement of the first plurality of spindles 30 mounted on the first plurality of guide supports 51 and therefore movable clockwise. Consequently, if one wishes to remove from the braiding a spindle 30 movable in the clockwise direction to place it in the reserve zone 20, for example to produce a portion of the braided structure of smaller section, but without risking that the wire from said movable spindle 30 does not create a singularity in the braiding or an undesired tension, it is possible to arrange said spindle 30 on the first crown 21 movable in the clockwise direction by making the positioning element 35 of said spindle 30 cooperate with a reserve support 52 present on the first crown 21. Thus, the thread coming from said spindle 30 will remain mobile in the clockwise direction in order to accompany the end of its braiding to the braided structure in progress, even if the spindle 30 has been removed from the braiding area and no longer participates in braiding.

Comparably, the second circumferential ring(s) 22 movable in the counterclockwise direction can accompany the movement of the second plurality of guide supports 51 movable on the guide path 100 in the counterclockwise direction, and consequently the movement of the second plurality spindles 30 mounted on the second plurality of guide supports 51 and therefore move counterclockwise. Consequently, if one wishes to remove from the braiding a spindle 30 movable in the counterclockwise direction to place it in the reserve zone 20, for example to produce a portion of the braided structure of smaller section, but without risking that the wire from said movable spindle 30 does not create a singularity in the braiding or an undesired tension, it is possible to arrange said spindle 30 on the second movable crown 22 in the counterclockwise direction by making the positioning element 35 of said spindle 30 cooperate with a reserve support 52 present on the second crown 22. Thus, the thread coming from said spindle 30 will remain mobile in the counterclockwise direction in order to accompany the end of its braiding to the braided structure in progress, even if the spindle 30 has been removed from the braiding area and no longer participates in braiding.

Thus, preferably, the movable circumferential crowns 21 and 22 are preferably intended to accommodate the spindles 30 temporarily and for a short duration, before said spindles 30 are arranged on the fixed crown(s) 23 for a longer duration. . The movable circumferential crowns 21 and 22 then correspond to a transition zone between the braiding zone 10 and the fixed parts of the reserve zone 20. Preferably, the arrangement of a spindle 30 on one of the movable crowns 21, 22 is therefore only provisional, for a duration preferably corresponding to the duration necessary for the thread coming from said spindle, which is in the process of intertwining with the other threads at the moment when said spindle is removed from the braiding zone, is entirely braided to the braided structure to be created. This greatly reduces the risk of singularities in the final braided structure.

As illustrated in the example of Figure 4, the machine according to the invention preferably comprises an overall drive system which comprises on the one hand the drive system 71 of the guide supports 51 and on the other hand the system drive 73, 74, 76, 21, 22 of the reserve supports 52.

In the example illustrated in Figures 1 to 4, the rotation drive system of the movable crowns 21 and 22, which belongs to the reserve support drive system 52, can be mechanically linked to the rotation drive system notched wheels 11, which belongs to the drive system of the guide supports 51. For example, as illustrated in Figure 4, the rotational drive system 71 of each notched wheel 11, preferably in the form of gears, is connected by a belt 72 to a pinion 73 belonging to the reserve zone 20. The movable crowns 21, 22 each comprise a circumferential rack 74, 76 actuated directly or indirectly by the pinion 73. Thus, in the example illustrated in Figure 4, the movement of the drive system 71 guide supports 51 is transmitted to the drive system 21, 22, 73, 74, 76 of the reserve supports 52 by means of a movement transmission system in the form of a belt 72.

Preferably, in order to further limit the risk of singularity in the braiding following a change in the number of spindles 30 participating in the braiding, the overall drive system is configured so that the angular speed of at least part of the braid supports reserve 52 is a function of the angular speed of at least part of the guide supports 51, so that the movement of at least part of the reserve supports 52 accompanies the movement of at least part of the guide supports 51. Preferably, the angular speed of at least part of the reserve supports 52 is equal to the angular speed of at least part of the guide supports 51, that is to say that at least part of the supports reserve 52 travels the same angular extent relative to the central axis of the machine as at least part of the guide supports for a given duration. The central axis of the machine can be defined for example as the axis passing through the drawing point or through the center of the shaping mandrel of the machine, and passing through the center of the main guide path. The angular velocity is expressed in radians per second and the angular extent in radians, the reference center being a point on the central axis of the braiding machine.

Thus, at least part of the guide supports makes a complete turn along the guide path 100 when at least part of the guide supports 51 makes a complete turn of the guide path 100.

In the example illustrated in Figures 1 to 4, the movable rings 21, 22 make a complete revolution around the guide path 100 when at least part of the spindles 30 make a complete revolution of the guide path 100. Thus, THE spindles 30 present on the first crown 21 movable in the clockwise direction follow the movement of the spindles 30 movable in the clockwise direction on the guide path 100, and the spindles 30 present on the second crown 22 movable in the counterclockwise direction follow the movement of the spindles 30 movable in the counterclockwise direction on the guide path 100. The reduction ratio between the rotation of the notched wheels 11 and the rotation of each circumferential ring 21, 22 must therefore preferably correspond to half the value of the number of notched wheels 11 per circumferential row. In the example illustrated in Figure 1, the braiding machine comprises a single row of notched wheels 11 comprising sixteen notched wheels 11. Thus, the value of the reduction ratio between the rotation of each gear 71 of said notched wheels 11 and the rotation of the rack 74, 76 of each movable crown 21, 22 will be eight.

The transfer of the spindles 30 between the braiding zone 10 and the reserve zone 20, or between the different parts or circumferential crowns 21, 22, 23 of the reserve zone 20, can be carried out manually or by one or more robotic arms 8 including a hooking and unhooking clamp. These robotic arms 8 are for example fixed around the braiding zone 10 and the reserve zone 20.

The braiding machine can also include a cutting system 9 configured to cut the threads coming from the spindles 30 arranged in the reserve zone 20, and in particular the threads coming from the spindles 30 arranged in the fixed parts of the reserve zone 20, in order to avoid any risk of entanglement of one of the threads not participating in braiding with the threads participating in braiding.

We will now describe in relation to schematic figures 5 to 7 an example of a braiding process according to the first aspect of the invention for the production of a braided structure 300 having significant variations in section, and more precisely significant variations in the perimeter of the section. Thus, the braided structure 300 to be produced comprises in its length a first zone having a first section perimeter, a transition zone, and a second zone having a second section perimeter, the second perimeter being different from the first perimeter. In the example illustrated in Figures 5 to 7, the first perimeter is greater than the second perimeter and the zone of transition presents a section whose perimeter decreases regularly between the first zone and the second zone.

In the example illustrated in Figures 5 to 7, the braiding is carried out on a conforming mandrel 5 which generally has the shape of the braided structure 300 to be produced. We do of course not depart from the scope of the invention if the braiding is not carried out on a conforming mandrel. The threads from the spools of the thread feed spindles are attached to a pulling point.

We begin by producing the first zone of the braided structure 300 by circulating a first number of thread supply spindles 30 along the guide path 100, inside the braiding zone 10. Thus, the threads 31 from the coils carried by this first number of spindles 30 intertwine around the conforming mandrel 5 so as to produce the first zone of the braided structure 300, as illustrated in Figure 5.

In order to produce the transition zone of the braided structure 300 whose perimeter of the section decreases while maintaining a density of threads and angles between the threads similar to the density of threads and the angles between the threads of the first zone of the braided structure 300, wire supply spindles 30 are gradually taken out of the braiding zone 10 to put them in the reserve zone 20. Thus, these supply spindles 30 are removed from the guide path 100 manually, or from automatic manner. Preferably, as illustrated in Figure 6, a robotic arm 8 as described above grasps a spindle 30 to be removed from the guide path 100 and separates it from the guide support 51 on which it was mounted by separating the positioning element 35 of said spindle 30 of the mounting surface 51b of the guide support 51. Then, the robotic arm 8 moves the spindle 30 towards the reserve zone 20, to mount it with one of the reserve supports 52 present in the reserve zone 20 by assembling the positioning element 35 of said spindle 30 with the mounting face 52b of said reserve support 52.

In the example illustrated in Figure 6, in order to produce the transition zone then the second zone of the braided structure 300, the robotic arms 8 gradually remove part of the spindles 30 moving in a clockwise direction on the guide path 100 and part of the spindles 30 movable in the direction counterclockwise on the guide path 100. The spindles 30 movable in the clockwise direction which are removed are then arranged on the reserve supports 52 of the first crown 21 movable in the clockwise direction and the spindles 30 movable in the counterclockwise direction which are removed are then arranged on the reserve supports 52 of the second crown 22 movable in the counterclockwise direction. When a part of the spindles 30 is arranged on the movable crowns 21 and 22, the threads 32 coming from said spindles 30 arranged on the movable crowns 21 and 22 no longer participate in the braiding but are in a transition stage, that is to say say that they are still in the process of intertwining with other threads without yet being completely braided and tightened. The rotation of the movable crowns 21, 22 makes it possible to accompany this transition step of the threads 32 coming from the spindles 30 coming out of the guide path 100 and the braiding zone 10.

When the thread 32 coming from a spindle 30 placed on a movable ring 21 or 22 has completed the transition step, that is to say it is no longer in the process of intertwining, the spindle 30 can be removed from the movable crown 21 or 22 to be placed on the fixed circumferential crown 23, manually or automatically. Preferably, as illustrated in Figure 7, the robotic arm 8 grasps a spindle 30 to be removed from a movable crown 21 or 22 and separates it from the reserve support 52 on which it was mounted by separating the positioning element 35 from said spindle 30 of the mounting surface 52b of the reserve support 52. Then, the robotic arm 8 moves the spindle 30 towards the fixed crown 23, to mount it with one of the reserve supports 52 present on said fixed crown 23 by assembling the positioning element 35 of said spindle 30 with the mounting face 52b of said reserve support 52 of the fixed crown 23. The wires 33 coming from the spindles arranged on the fixed crown 23 can be cut by the cutting device 9, in order to avoid any risk of entanglement of one of the threads 33 not participating in braiding with the threads 31 participating in braiding.

When the braiding of the transition zone of the structure 300 is completed, there remains only a second number of spindles 30 movable along the guide path 100, inside the braiding zone 10. In the example illustrated on the Figures 5 to 7, the second number of movable spindles 30 is less than the first number of movable spindles 30 during braiding of the first zone.

The second number of spindles 30 movable on the guide path 100 then makes it possible to braid the second zone of the braided structure 300, the wires 31 coming from the coils carried by this second number of spindles 30 intertwining around the conforming mandrel 5 as illustrated in Figure 7 to produce the braided structure 300.

In a variant not illustrated, it is possible to produce a braided structure having in its length a first zone having a first section perimeter, a transition zone and a second zone having a second section perimeter, as in the example illustrated in the figures 5 to 7, but further comprising a second transition zone and a third zone having a third section perimeter. The third perimeter of the third section is here greater than the second perimeter of the second section, and may also be less than or greater than the first perimeter of the first section. We of course do not depart from the scope of the invention if the third section perimeter is less than the first and second section perimeters.

In this variant, the first zone, the transition zone and the second zone are produced as described previously. In order to produce the second transition zone of the braided structure, located in the extension of the second zone and whose perimeter of the section increases, while maintaining a density of threads and angles between the threads similar to the density of threads and at the angles between the threads of the first zone and the second zone already braided, spindles supplying threads present in the reserve zone are gradually transferred to the braiding zone to make them participate in braiding.

Thus, these supply spindles are removed from the fixed crown of the reserve zone manually, or automatically. Preferably, a robotic arm as described above grasps a spindle to be removed from the fixed crown and separates it from the reserve support on which it was mounted by separating the positioning element of said spindle from the mounting surface of the reserve support. Then, the robotic arm moves the spindle towards one of the moving parts of the zone of reserve, to mount it with one of the reserve supports present on the first or second movable crown by assembling the positioning element of said spindle with the mounting face of said reserve support. In our variant example, in order to create the second transition zone then the third zone of the braided structure, the robotic arms place part of the spindles present on the fixed crown on the movable crown in the clockwise direction and part of the spindles present on the fixed crown on the movable crown counterclockwise.

When the threads coming from the spindles positioned on the movable crowns accompany the movement of the threads during braiding, the robotic arm(s) gradually move the spindles arranged on the movable crown in a clockwise direction on the guide sub-path(s) traveled by guide supports in the clockwise direction, and the spindles arranged on the movable ring in the counterclockwise direction on the guide sub-path(s) traversed by the guide supports in the counterclockwise direction, by mounting the positioning element of said spindles with the mounting faces of said guide supports not carrying spindles. Thus, the threads coming from the spindles mounted on the guide supports participate in the braiding.

The prior passage of the thread supply spindles over moving parts of the reserve zone before their participation in braiding makes it possible to facilitate the introduction into the braiding of the threads from said added spindles.

When the braiding of the second transition zone of the structure is completed, there is therefore a third number of spindles, greater than the second number of spindles, movable along the guide path, inside the braiding zone.

The third number of mobile spindles on the guide path then makes it possible to braid the third zone of the braided structure, the threads coming from the coils carried by this third number of spindles intertwining around the shaping mandrel.

The term “yarn” used in the present application can designate a single thread or a single fiber, but can also designate a wick or a braid. In particular, the threads may be carbon fibers, ceramic fibers, or a mixture of carbon fibers and ceramic fibers. The braided structure according to the method of the invention can be a fibrous structure, which could possibly be consolidated or densified by a matrix in order to form the fibrous reinforcement of a part made of composite material. The braided structure according to the process of the invention can thus form, for example, all or part of the fibrous reinforcement of a part made of composite material for the automobile, aeronautics or space industries. In particular, the braided structure obtained could form, for example, the fibrous reinforcement of a divergent or a rocket engine nozzle.

The braided structure according to the method of the invention can also allow the formation of straps or ropes.

A second aspect of the invention is presented in relation to Figures 8 to 16.

Figures 8 and 9 schematically illustrate an example of a braiding machine according to the second aspect of the invention making it possible to produce a braided structure. The braiding machine comprises a plate 61 and a plurality of thread feed spindles 63. The plate 61 is preferably horizontal, in order to facilitate its maintenance and that of the thread feed spindles 63. However, one does not leave the framework of the invention if the plate 61 is vertical or inclined.

The plate 61 comprises a braiding zone 610 and a reserve zone in the form of several reserve regions 620 distributed along the outer edge of the braiding zone 610, and separated or not from each other. We of course do not depart from the scope of the invention if the reserve zone does not belong to the plate comprising the braiding zone.

We do of course not depart from the scope of the invention if the braiding machine only has a single continuous reserve zone circumferential to the braiding zone. We also do not depart from the scope of the invention if the circumferential reserve zone is movable in rotation around the braiding zone, for example in the case where the reserve zone is a continuous crown movable in rotation around the zone braiding. The reserve zone, in the form or not of several disjointed regions, is preferably located on the outside of the braiding zone 610, that is to say around the main guide path 6100, in order to facilitate its accessibility. . However, we do not depart from the scope of the invention if the reserve zone, in the form or not of several disjointed regions, is located inside the braiding zone 610.

The braiding zone 610 includes a main guide path 6100. The wire feed spindles 63 movable along this main guide path 6100 participate in the braiding of the braided structure. The main guide path 6100 is therefore configured to be traveled in a clockwise direction by a first plurality of zones 63, and in an anti-clockwise direction by a second plurality of zones 63. In the example illustrated in Figures 8 and 9 , the main guide path 6100 comprises two sub-guide paths 6110 and 6120 which regularly intersect, the first sub-guide path 6110 being configured to be traversed by the first plurality of spindles 63 and the second sub-path 6120 being configured to be traversed by the second plurality of spindles 63. We of course do not depart from the scope of the invention if the main guide path comprises more than two sub-paths, for example if we wish to produce a braided structure comprising several layers or having a complex binding weave, such as for example interlock braiding.

The reserve regions 620 each include a secondary guide path 6200. Unlike the wire feed spindles 63 present in the braiding zone 610, the wire feed spindles 63 present in the secondary guide path 6200 of these reserve regions 620, or more generally of the reserve zone, do not participate in the braiding of the braided structure. Each secondary guide path 6200 is therefore configured to maintain one or more feed spindles in one of the reserve regions 620, that is to say outside the braiding zone 610 and the main guide path 6100. Preferably, there is no direct communication between the different secondary guide paths.

Each thread supply spindle 63 carries a spool of braiding threads and includes a guide support capable of moving along the guide paths main 6100 and secondary 6200. In a well-known manner, each coil of braiding threads is connected to a tension management and thread return system.

The braiding machine further comprises at least one drawing point located at a distance from the plate 61, and to which the wires from the bobbins carried by the mobile feed spindles 63 are connected along the main guide path 6100.

Preferably, the braiding machine comprises a shaping mandrel 65, which is a shape on which the intertwined threads come to rest to form the tight braid. In this case, the braiding machine makes it possible to carry out so-called “over-braiding” processes. The braiding machine according to the invention is particularly interesting in the case where it is desired to produce a braid having significant variations in section, and more precisely a braid whose perimeter of the section varies significantly. Consequently, the advantages provided by the braiding machine according to the invention are particularly remarkable when said braiding machine comprises a conforming mandrel 65 whose shape has strong variations in thickness.

Preferably, the main 6100 and secondary 6200 guide paths are machined in the mass of the plate 61 in the form of grooves, having for example a substantially rectangular section, open towards the outside, and inside which the supports move guiding the feed spindles 63.

Preferably and in a well-known manner, the braiding zone 610 of the plate 61 comprises a plurality of main notched wheels 611 configured to be rotated in order to circulate the wire feed spindles 63 along the main guide path 6100, as shown in Figure 10.

Preferably, each reserve region 620 of the plate 61 also comprises at least one secondary notched wheel 622 configured to be rotated in order to circulate one or more wire feed spindles 63 in the secondary guide path 6200 of said reserve region 620, as illustrated in Figure 10. Preferably, each reserve region 620 and each secondary guide path 6200 comprises a single secondary notched wheel 622. Preferably, each secondary notched wheel 622 is adjacent to a wheel has main notch 611. When a spindle 63 is maintained in the reserve zone 620, on a secondary guide path 6200, there is preferably no passage of the spindle 63 from one notched wheel 622 to another. Thus, preferably, the spindle can circulate along the secondary guide path 6200, but only over a region of limited angular extent.

As illustrated in Figure 10, each main notched wheel 611 or secondary 622 preferably comprises four notches. The main notched wheels 611 or secondary 622 are preferably rotated in a well-known manner via gear trains controlled by one or more motors.

Preferably, each secondary notched wheel 622 of the braiding machine is linked to a rotation decoupling system, configured to make the rotation of said secondary notched wheel 622 independent of the rotation of the adjacent main notched wheel 611.

Each secondary guide path of the reserve zone is linked to the braiding zone 610 via a switching element. This switching element is movable between a first position making it possible to isolate the secondary guide path 6200 from said reserve zone 620 of the main guide path 6100, and a second position making it possible to connect the secondary guide path 6200 to said zone reserve 620 to the main guide path 6100, in order to allow the passage of at least one supply spindle 63 between the main guide path 6100 and the secondary guide path 6200. Thus, two branches 6101 and 6102 of the guide path main guide 6100 and two branches 6201 and 6202 of secondary guide path 6200 open onto each switching element.

Several types of switching element are possible in the context of the present invention.

According to a first embodiment of the invention, the switching element is movable in translation, in accordance with the examples illustrated in Figures 10 to 12. In the example illustrated in Figures 10 and 11, the switching element 641 is in the form of a flat solid movable in translation in a direction of translation D _T I tangent to the junction between the reserve zone 620 and the braiding zone 610. The switching element 641 comprises grooves 6411, 6412, 6413 and 6414 of substantially rectangular section, open towards the outside, and configured to allow the passage of a spindle guide support d food 63.

The switching element 641 comprises a first groove 6411, a second groove 6412, a third groove 6413 and a fourth groove 6414. As illustrated in Figures 10 and 11, the first groove 6411 and the second groove 6412 do not have any common intersection, so that when the switching element 641 is in its first position, the first groove 6411 belongs entirely to the main guide path 6100 and the second groove 6412 belongs entirely to the secondary guide path 6200. Thus, when the switching element 641 is in its first position, the first groove 6411 connects the two branches 6101 and 6102 of the main guide path 6100 and the second groove 6412 connects the two branches 6201 and 6202 of the secondary guide path 6200.

As illustrated in Figures 10 and 11, the third groove 6413 and the fourth groove 6414 of the switching element 641 intersect, so that when the switching element 641 is in its second position, illustrated in the figure 11, the third groove 6413 connects the first branch 6101 of main guide path 6100 to the second branch 6202 of secondary guide path 6200 and the fourth groove 6414 connects the second branch 6102 of main guide path 6100 to the first branch 6201 of secondary guide path 6200.

Preferably, the first and second grooves 6411 and 6412 have a curved trajectory, while the third and fourth grooves 6413 and 6414 have a rectilinear trajectory.

In the example illustrated in Figure 12, the switching element 642 is in the form of a flat solid movable in translation in a direction of translation D _T 2 perpendicular to the junction between the reserve zone 620 and the braiding zone 610. The switching element 642 comprises grooves 6421, 6422, 6423 and 6424 of Tl substantially rectangular section, open towards the outside, and configured to allow the passage of a feed spindle guide support 63.

The switching element 642 comprises a first groove 6421, a second groove 6422, a third groove 6423 and a fourth groove 6424. As illustrated in Figure 12, the first groove 6421 and the second groove 6422 are isolated from each other. the other and do not have a common intersection, so that when the switching element 642 is in its first position, illustrated in Figure 12, the first groove 6421 belongs entirely to the main guide path 6100 and the second groove 6422 belongs entirely to the secondary guide path 6200. Thus, when the switching element 642 is in its first position, the first groove 6421 connects the two branches 6101 and 6102 of the main guide path 6100 and the second groove 6422 connects the two branches 6201 and 6202 of secondary guide path 6200.

As illustrated in Figure 12, the third groove 6423 and the fourth groove 6424 of the switching element 642 intersect, so that when the switching element 642 is in its second position, the third groove 6423 connects the first branch 6101 of main guide path 6100 to the second branch 6202 of secondary guide path 6200 and the fourth groove 6424 connects the second branch 6102 of main guide path 6100 to the first branch 6201 of secondary guide path 6200.

Preferably, the first and second grooves 6421 and 6422 have a curved trajectory, while the third and fourth grooves 6423 and 6424 have a rectilinear trajectory.

In the example illustrated in Figures 13A and 13B, the switching element 643 is in the form of two flat solids 643a, 643b movable in translation in a direction of translation perpendicular to the junction between the reserve zone 620 and the braiding zone 610, the first solid 643a translating in a direction opposite to the second solid 643b. Each solid 643a, 643b of the switching element 643 has a rounded edge opposite a straight edge. When the switching element 643 is in the first position, the straight edge of the first solid 643a is in contact with the right edge of the second solid 643b, so that the rounded edge of the first solid 643a defines part of the guide path main 6100 by connecting the two branches 6101 and 6102 of the main guide path 6100 and so that the rounded edge of the second solid 643b defines part of the secondary guide path 6200 by connecting the two branches 6201 and 6202 of the secondary guide path 6200 When the switching element 643 is in the second position, the rounded edge of the first solid 643a is in contact with one of the walls of the main guide path 6100 and the rounded edge of the second solid 643b is in contact with the one of the walls of the secondary guide path 6200, so that the gap generated between the right edge of the first solid 643a and the right edge of the second solid 643b allows the passage of a feed spindle 63 of the first branch 6101 of main guide path 6100 to the second branch 6202 of secondary guide path 6200, and from the second branch 6102 of main guide path 6100 to the first branch 6201 of secondary guide path 6200.

According to a second embodiment of the invention, the switching element is movable by rotation, in accordance with the examples illustrated in Figures 14 to 16.

In the example illustrated in Figure 14, the switching element 644 is in the form of a flat circular solid movable in rotation along an axis of rotation perpendicular to the plate 61. The switching element 644 comprises grooves 6441, 6442, 6443 and 6444 of substantially rectangular section, open towards the outside, and configured to allow the passage of a feed spindle foot 63.

The switching element 644 comprises a first groove 6441, a second groove 6442, a third groove 6443 and a fourth groove 6444. As illustrated in Figure 14, the first groove 6441 and the second groove 6442 do not have an intersection common, so that when the switching element 644 is in its first position, the first groove 6441 belongs entirely to the main guide path 6100 and the second groove 6442 belongs entirely to the secondary guide path 6200. Thus, when the switching element 644 is in its first position, the first groove 6441 connects the two branches 6101 and 6102 of the main guide path 6100 and the second groove 6442 connects the two branches 6201 and 6202 of the secondary guide path 6200.

As illustrated in Figure 14, the third groove 6443 and the fourth groove 6444 of the switching element 644 intersect, so that when the switching element 644 is in its second position, illustrated in Figure 14, the third groove 6443 connects the first branch 6101 of the main guide path 6100 to the second branch 6202 of the secondary guide path 6200 and the fourth groove 6444 connects the second branch 6102 of the main guide path 6100 to the first branch 6201 of the guide path secondary guidance 6200.

Preferably, the first and second grooves 6441 and 6442 have a curved trajectory, while the third and fourth grooves 6443 and 6444 have a rectilinear trajectory.

In the example illustrated in Figure 15, the switching element 645 is in the form of a flat solid of generally triangular shape connected by a pivot connection to the plate 61 and movable in rotation along an axis of rotation perpendicular to the plate 61. When the switching element 645 is in the first position, the tip of the flat solid is positioned between the main guide path 6100 and the secondary guide path 6200, so that a first edge of the flat solid defines a part of the main guide path 6100 by connecting the two branches 6101 and 6102 of the main guide path 6100 and that a second edge of the flat solid, opposite the first edge of said solid, defines a part of the secondary guide path 6200 by connecting the two branches 6201 and 6202 of secondary guide path 6200. When the switching element 645 is in the second position, the tip of the flat solid is positioned in contact with one of the walls of the main guide path 6100, or in contact with one of the walls of the secondary guide path 6200 as illustrated in Figure 15. When the tip of the flat solid is positioned in contact with one of the walls of the main guide path 6100, the gap released between said flat solid and the secondary guide path 6200 allows the passage of a supply spindle 63 between the first branch 6201 of the secondary guide path 6200 and the second branch 6102 of the main guide path 6100. When the tip of the flat solid is positioned in contact with one of the walls of the secondary guide path 6200, as illustrated in Figure 15, the distance cleared between said flat solid and the main guide path

6100 allows the passage of a supply spindle 63 between the second branch 6202 of the secondary guide path 6200 and the first branch 6101 of the main guide path 6100.

In the example illustrated in Figure 16, the switching element 646 is in the form of four flat solids 646a, 646b, 646c, 646d of generally triangular shape and movable in rotation along an axis of rotation perpendicular to the plate 61 The first solid 646a is present on the second branch 6102 of the main guide path 6100. The second solid 646b is present on the second branch 6202 of the secondary guide path 6200. The third solid 646c is present on the first branch 6201 of the path secondary guide 6200. The fourth solid 646d is present on the first branch 6101 of the main guide path 6100.

Thus, when the switching element 646 is in the first position, the first solid 646a and the fourth solid 646d each define a wall of the main guide path 6100 by blocking the passage towards the secondary guide path 6200. When the switching element 646 is in the second position, according to a first mode, the first solid 646a pivots to connect the second branch 6102 of the main guide path 6100 to the first branch 6201 of the secondary guide path 6200, the second solid 646b and the third solid 646c being positioned so as to authorize this connection, as illustrated in Figure 16. According to a second mode, the fourth solid 646d pivots to connect the first branch

6101 from the main guide path 6100 to the second branch 6202 of the secondary guide path 6200, the second solid 646b and the third solid 646c being positioned so as to authorize this connection.

In each of the preceding examples, the switching element can be controlled manually, for example by means of a joystick, or automatically, for example by means of a control unit configured to actuate said switching element.

The switching element(s) can be connected to the gear system allowing the movement of the feed spindles 63, for example to the gear train driving the rotation of the notched wheels 611 or 622. The use of an element movable switch in rotation is particularly interesting in this case, this configuration allowing a simplified mechanism for actuating the switch element and easy integration under the plate 61 of the braiding machine.

We will now describe in relation to Figures 8 and 9 an example of a braiding process according to the second aspect of the invention for the production of a braided structure 6300 having significant variations in section, and more precisely significant variations in the perimeter. of the section. Thus, the braided structure 6300 to be produced comprises in its length a first zone having a first section perimeter, a transition zone, and a second zone having a second section perimeter, the second perimeter being different from the first perimeter. Unless otherwise stated, the sections are taken perpendicular to a longitudinal axis of the braided structure. In the example illustrated in Figures 8 and 9, the first perimeter is greater than the second perimeter and the transition zone presents a section whose perimeter decreases regularly between the first zone and the second zone.

In the example illustrated in Figures 8 and 9, the braiding is carried out on the conforming mandrel 65 which generally has the shape of the braided structure 6300 to be produced. We do of course not depart from the scope of the invention if the braiding is not carried out on a conforming mandrel. The threads coming from the spools of the thread supply spindles 63 are fixed to a pulling point.

We begin by producing the first zone of the braided structure 6300 by circulating a first number of wire feed bobbins 63 along the main guide path 6100, inside the braiding zone 610. Thus, the wires 631 from the coils carried by this first number of spindles 63 intermingle around the conforming mandrel 65 so as to produce the first zone of the braided structure 6300, as illustrated in Figure 8.

In order to produce the transition zone of the braided structure 6300 whose perimeter of the section decreases while maintaining a density of threads and angles between the threads similar to the density of threads and the angles between the threads of the first zone of the braided structure 6300, wire feed spindles 63 are gradually taken out of the braiding zone 610 to put them in the reserve zone 620. Thus, these feed spindles 63 leave the main guide path 6100 by means of a switching element to be maintained in a secondary guide path 6200, in order to no longer participate in the braiding of the structure 6300. Consequently, the wires 632 coming from the coils carried by the spindles 63 maintained in the reserve zone 620 are no longer braided.

These threads 632 can be cut by a cutting device (not shown) configured to cut the thread 632 coming from a feed spindle 63 present in the reserve zone 620 while the braiding operation continues, in order to avoid any risk of entanglement of one of these wires 632 not participating in braiding with the wires 631 participating in braiding.

When the braiding of the transition zone of the structure 6300 is completed, there remains only a second number of wire feed spindles 63 movable along the main guide path 6100, inside the zone of braiding 610. In the example illustrated in Figures 8 and 9, the second number of mobile feed spindles 63 is less than the first number of mobile spindles 63 during braiding of the first zone.

The second number of wire supply spindles 63 movable on the main guide path 6100 then makes it possible to braid the second zone of the braided structure 6300, the wires 631 coming from the spools carried by this second number of spindles 63 intertwining around of the conformation mandrel 65 as illustrated in Figure 9.

In a variant not illustrated, it is possible to produce a braided structure having in its length a first zone having a first section perimeter, a transition zone and a second zone having a second section perimeter, as in the example illustrated in Figures 8 and 9, but further comprising a second transition zone and a third zone having a third section perimeter. The third perimeter of the third section is here greater than the second perimeter of the second section, and may also be less than or greater than the first perimeter of the first section. We of course do not depart from the scope of the invention if the third section perimeter is less than the first and second section perimeters.

In this variant, the first zone, the transition zone and the second zone are produced as described previously. In order to produce the second transition zone of the braided structure, located in the extension of the second zone and whose perimeter of the section increases, while maintaining a density of threads and angles between the threads similar to the density of threads and at the angles between the threads of the first zone and the second zone already braided, spindles supplying threads present in the reserve zone are gradually transferred to the braiding zone to make them participate in braiding. Thus, these feed spindles leave, via a switching element, the secondary guide path in which they were held to be introduced onto the main guide path, in order to participate in the braiding of the structure. Consequently, the wires from the coils carried by the spindles added to the main guide path are braided with the wires from the coils carried by the second number of spindles already present on the main guide path.

When the braiding of the second transition zone of the structure is completed, a third number of yarn feed spindles are movable along the main guide path, within the braiding zone. The third number of spindles supplying mobile wires on the main guide path 6100 then makes it possible to braid the third zone of the braided structure, the wires coming from the spools carried by this third number of spindles intertwining around the shaping mandrel. .

The term “yarn” used in the present application can designate a single thread or a single fiber, but can also designate a wick or a braid. In particular, the threads may be carbon fibers, ceramic fibers, or a mixture of carbon fibers and ceramic fibers. The braided structure according to the method of the invention can be a fibrous structure, which could possibly be consolidated or densified by a matrix in order to form the fibrous reinforcement of a part made of composite material. The braided structure according to the process of the invention can thus form, for example, all or part of the fibrous reinforcement of a part made of composite material for the automobile, aeronautics or space industries. In particular, the braided structure obtained could form, for example, the fibrous reinforcement of a divergent or a rocket engine nozzle. The braided structure according to the method of the invention can also allow the formation of straps or ropes.

Claims

Claims [Claim 1] Braiding machine comprising: - a plurality of wire feed spindles (63) movable along a main guide path (6100) so as to participate in braiding, characterized in that it further comprises: - a reserve zone (620) adjacent to the main guide path (6100), located around the main guide path (6100), and comprising at least one secondary guide path (6200) capable of receiving at least one spindle (63 ) and to maintain it in the reserve zone (620) so as to interrupt its participation in braiding, each secondary guide path (200) being associated with at least one switching element (641, 642, 643, 644, 645 , 646) which is movable between a first position preventing communication between the main guide path (6100) and the secondary guide path (6100), and a second position authorizing this communication and configured to allow a passage of at least one spindle (63) between the main guide path (6100) and the secondary guide path (6200), and - a cutting device configured to cut a wire (632) coming from a feed spindle (63) present in the reserve zone (620) while the braiding operation continues. [Claim 2] Machine according to claim 1, said machine further comprising a shaping mandrel (65) on which the braiding is intended to be carried out. [Claim 3] Machine according to claim 1 or 2, in which the reserve region (620) is formed by a plurality of reserve regions distributed along the main guide path (6100), each reserve region comprising a path of secondary guidance (6200) separated from the secondary guide paths (6200) of the other reserve regions. [Claim 4] Machine according to any one of claims 1 to 3, said machine comprising a plurality of main notched wheels (611) configured to be rotated in order to circulate the feed spindles (63) along the main guide path (6100), said machine further comprising one or more secondary notched wheels (622) in the reserve area (620), each secondary guide path (6200) of the reserve area (620 ) being associated with at least one secondary notched wheel (622) configured to be rotated in order to circulate at least one feed spindle (63) along said secondary guide path (6200). [Claim 5] Machine according to claim 4, said machine comprising at least one rotation decoupling system configured to make the rotation of at least one secondary notched wheel (622) independent of the rotation of the main notched wheels (611). ). [Claim 6] Machine according to any one of claims 1 to 5, in which at least part of the switching elements (641, 642, 643) is movable in translation to move from the first to the second position. [Claim 7] Machine according to any one of claims 1 to 6, in which at least part of the switching elements (644, 645, 646) can rotate to move from the first to the second position. [Claim 8] Machine according to any one of claims 1 to 7, said machine further comprising a control unit configured to actuate the switching element (641, 642, 643, 644, 645, 646). [Claim 9] Method for braiding a braided structure (6300) comprising a first zone having a first section and a second zone having a second section different from the first section, the method using a machine according to any one of claims 1 to 8 and comprising: - braiding the first zone of the braided structure (6300) with a first number of wire feed spindles (63) movable along the main guide path (6100), and - braiding the second zone of the braided structure (6300) with a second number of wire feed spindles (63) movable along the main guide path (6100), the second number of spindles being different from the first number spindles thanks to the passage of spindles (63) between the main guide path (6100) and the reserve zone (620) by actuation of the switching element (641, 642, 643, 644, 645, 646). [Claim 10] Braiding machine comprising: - a plurality of wire feed spindles (30) connected to guide supports (51) and movable along a guide path (100) so as to participate in the braiding, all or part of the spindles (30) being integral with a positioning element (35) cooperating with a corresponding guide support (51) and removable relative to the latter, - a plurality of reserve supports (52) located outside the guide path (100), said reserve supports (52) being capable of receiving spindles (30) for feeding wire placed in reserve so as to interrupt their participation in braiding, the positioning elements (35) being able to cooperate with the reserve supports (52) to achieve this reserve, the braiding machine being characterized in that it comprises a drive system ( 73, 74, 76, 21, 22) reserve supports (52) capable of driving at least part of the reserve supports (52) circumferentially to the guide path (100). [Claim 11] Machine according to claim 10, in which the drive system (73, 74, 76, 21, 22) of the reserve supports (52) comprises at least a first ring (21) circumferential to the guide path ( 100) and capable of rotating in a first direction of rotation and at least one second ring (22) circumferential to the guide path (100) and capable of rotating in a second direction of rotation opposite to the first direction of rotation, each first or second crown (21, 22) carrying one or more reserve supports (52). [Claim 12] Machine according to claim 10 or 11, wherein the reserve supports (52) are present around the guide path (100). [Claim 13] Machine according to any one of claims 10 to 12, said machine comprising an overall drive system comprising the drive system (73, 74, 76, 21, 22) of the reserve supports (52) and a system drive (71) of the guide supports (51), the overall drive system being configured so that the angular speed of at least a part of the reserve supports (52) is a function of the angular speed of at least one at least a part of the guide supports (51) so that the movement of at least a part of the reserve supports (52) accompanies the movement of at least a part of the guide supports (51). [Claim 14] Machine according to claim 13, wherein the overall drive system comprises a transmission system (72) configured to transmit movement of a drive system (71) from the guide supports (51) to the system drive (73, 74, 76, 21, 22) of the reserve supports (52). [Claim 15] Machine according to any one of claims 10 to 14, said machine further comprising a shaping mandrel (5) on which the braiding is intended to be carried out. [Claim 16] Machine according to any one of claims 10 to 15, said machine further comprising a robotic arm (8) configured to move at least one spindle (30) between a guide support (51) and a reserve support (52). [Claim 17] Machine according to any one of claims 10 to 16, said machine further comprising a cutting device (9) configured to cut a wire (32, 33) coming from a feed spindle (30) of which the positioning element (35) cooperates with a reserve support (52). [Claim 18] Method for braiding a braided structure (300) comprising a first zone having a first section and a second zone having a second section different from the first section, the method using a machine according to any one of claims 10 to 17 and comprising: - braiding the first zone of the braided structure (300) with a first number of wire feed spindles (30) movable along the guide path (100), and - braiding the second zone of the braided structure (300) with a second number of wire feed spindles (30) movable along the guide path (100), the second number of spindles being different from the first number of spindles thanks to the movement of spindles (30) between the guide supports (51) and the reserve supports (52) by cooperation of the positioning element (35) of said spindles moved with the guide supports (51) or reserve (52).