EP3303687B1 - Unit for producing an assembly - Google Patents

Description

The invention relates to an installation for manufacturing an assembly of wire elements.

A tire for heavy goods vehicles with a radial carcass reinforcement is known from the state of the art. Such a tire comprises a radial carcass reinforcement anchored in two beads and surmounted radially by a crown reinforcement itself surmounted by a tread which is joined to the beads by two sidewalls.

In such a tire, the crown reinforcement comprises a working reinforcement, a hooping reinforcement, a protective reinforcement, and optionally, a triangulation reinforcement. The relative arrangement of these reinforcements with respect to each other may vary. Generally, the protective reinforcement is the radially outermost reinforcement, the working reinforcement is the radially innermost reinforcement, the hooping reinforcement being arranged between the protective reinforcement and the working reinforcement.

Each armature comprises a single or several layers. Each ply comprises reinforcing elements arranged side by side parallel to each other. The reinforcing elements make an angle which varies according to the reinforcement to which the layer belongs. Each reinforcing element comprises one or more assemblies of wire elements, each assembly comprising several single metal wires assembled together, either by cabling or by twisting.

Known from the state of the art is an assembly of wire elements comprising a single layer of wire elements, here three wires, having a diameter of 0.26 mm wound together in a helix at a pitch of 5 mm. This assembly is designated by the designation “3.26” in accordance with the usual nomenclature.

In order to ensure the proper functioning of each reinforcement, and in particular of the hooping and protection reinforcements, it is desired to be able to control the structural elongation of these assemblies of wire elements, and quite particularly to be able to obtain a high structural elongation when this is proves necessary. The use of a conventional twisting process makes it possible to obtain a structural elongation at most equal to 0.5% for the cable 3.26 described above.

In order to increase the value of the structural elongation, several methods and installations are known from the state of the art for manufacturing an assembly of wire elements comprising a single layer of several wire elements wound together in a helix. Such processes and installations are in particular described in the document EP0143767 . During these processes, in order to obtain the highest possible structural elongation, the wire elements are individually preformed, then the preformed wire elements are assembled by wiring.

To this end, the installation comprises supply means and individual preforming means for each wire arranged in a rotating nacelle arranged upstream of the assembly point of the wire elements together. The heavier the feed and preforming means, the more the nacelle must be dimensioned so as to mechanically resist the inertia generated by the mass of the assembly of the nacelle, the feed means and the preforming means. In order to limit this inertia, it is therefore necessary to work at relatively low speeds of rotation, which limits the productivity of the installation.

In addition, this step of preforming the wire elements does not make it possible to achieve high structural elongations. Indeed, the use of an assembly method using a step of preforming the wires makes it possible to obtain a structural elongation at most equal to 2.0% for the cable 3.26 described above.

Other methods of assembly by twisting and cabling of the wire elements are known from DE4019584 .

The object of the invention is to obtain assemblies of wire elements having a high structural elongation and this, by using a more productive installation than that of the state of the art.

To this end, the subject of the invention is an installation for manufacturing an assembly of wire elements wound together in a helix according to claim 1.

Thanks to the installation according to the invention, it is possible, if necessary, to obtain a relatively high structural elongation and this with a relatively high productivity.

Indeed, thanks to the assembly means by twisting, it is not necessary that the means located upstream of the assembly point be arranged 2015PAT00178WO in a rotating nacelle unlike an assembly by wiring. The assembly means of the installation according to the invention can then be dimensioned independently of the assembly speed. Thus, it is possible to use means for supplying each wired element with a relatively high capacity (and therefore relatively heavy) which makes it possible to stop the installation less often.

In addition, the preforming and twisting means can be dimensioned independently of each other, in particular as regards their bulk and their mass. Unlike an installation comprising assembly means by wiring in which the mass and the size of the means located upstream of the assembly point must be as low as possible, the installation according to the invention makes it possible to use large varieties of means without being limited by the bulk or the mass of the preforming and twisting means.

Finally, the individual twisting means of each wire element being arranged upstream of the individual preforming means, no action is taken on the curvature of the wire elements obtained during and after the preforming step using the individual preforming means. Indeed, the individual preforming step taking place downstream of the individual twisting step, the twisting cannot eliminate the helix subsequently created by the preforming. The assemblies obtained after the assembly step have significant aeration linked to the preservation of the curvature of the preformed wire elements. This aeration makes it possible to obtain assemblies having a significant structural elongation if this proves to be necessary.

Contrary to the state of the art in which the wire elements are assembled by wiring and in which the wire elements do not undergo torsion around their own axis (due to a synchronous rotation before and after the point of assembly) , the installation according to the invention comprises individual twisting means for each wire element allowing each wire element to undergo individual twisting around its own axis. During this individual torsion, each wire element is plastically deformed and a residual torque is generated within each wire element. Also, during this step of individual twisting of each wire element, each wire element is then balanced by untwisting so as to cancel out this residual torque. Thus, after the individual twisting step and before the individual preforming step, each filamentary element is twisted and balanced.

By wire element, we mean any slender element of great length relative to its cross section, regardless of the shape of the latter, for example circular, oblong, rectangular or square, or even flat, this wire element possibly being for example twisted or wavy. When it is circular in shape, its diameter is preferably less than 3 mm.

By helical preformation is meant a three-dimensional helix inscribed in a cylinder having a main axis defining the axis of the helix. The three-dimensional helix defines a trajectory whose projection on a plane orthogonal to its helix axis is a circle and whose projection on a plane parallel to its helix axis is a sinusoid. Preferably, the assembly means comprise a distributor and an assembly grain.

Advantageously, the installation comprises means for maintaining the rotation of the assembly arranged downstream of the assembly grain.

In one embodiment, the assembly means comprise a lyre arranged downstream of the assembly grain.

Preferably, the assembly means comprise a nacelle arranged downstream of the assembly grain carrying means for storing the assembly.

Advantageously, the nacelle carries assembly balancing means.

Optionally, the installation comprises means for supplying at least the first and second wire elements arranged upstream of the twisting means.

According to the invention, the assembly of wire elements comprises a single layer formed by the wire elements of the assembly. In this embodiment, the assembly has no central core arranged around which the wire elements of the layer would be wound.

In another embodiment which does not fall within the scope of the invention and is present only by way of illustration, the assembly of wire elements comprises a layer of wire elements wound together in a helix around a central core.

In a variant which does not fall within the scope of the invention and is present only by way of illustration, the method comprises a step of assembling the layer of wire elements wound together in a helix around the central core so that the the central core has a substantially non-zero torsion.

In this variant which is not part of the invention and is only present by way of illustration, in the case where the central core is textile and whose substantially non-zero torsion does not impact the torsion balancing of the assembly. By substantially non-zero is meant that the core has a torsion greater than 10 turns per meter.

By textile, it is meant that the central core is non-metallic. Blade central can then comprise a single elementary textile monofilament or else several multifilament textile strands comprising several elementary textile monofilaments. In a variant, the transitional core comprises a single multifilamentary strand called surtors comprising several elementary monofilaments. In a variant, the transitional core comprises several multifilament strands, each called a twist, each comprising several elementary monofilaments and assembled together in a helix to form a twist.

Advantageously, the or each textile material of each elementary textile monofilament is chosen from a polyester, a polyamide, a polyketone, a polyvinyl alcohol, a cellulose, a mineral fiber, a natural fiber or a mixture of these materials.

Among the polyesters, mention will be made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), polypropylene terephthalate (PPT) or polypropylene naphthalate (PPN). Among the polyamides, mention will be made of an aliphatic polyamide such as nylon or an aromatic polyamide such as aramid. Among the polyvinyl alcohols, mention will be made of ^Kuralon® . Among the celluloses, mention will be made of rayon. Among the mineral fibers, mention will be made of glass and carbon fibers. Among the natural fibers, mention will be made of hemp or flax fibers.

In a variant which does not fall within the scope of the invention and is present only by way of illustration, the method comprises a step of assembling the layer of wire elements wound together in a helix around the central core so that the the central core has substantially zero torsion. This variant is used in particular in the case where the central core is metallic and whose substantially non-zero torsion would significantly impact the torsion balancing of the assembly. By substantially zero, it is meant that the core has a torsion of less than 10 turns per meter.

Advantageously, the layer comprises between 2 and 9 wire elements, preferably between 5 and 9 wire elements. By between 2 and 9 wire elements, it is understood that the layer can comprise 2, 3, 4, 5, 6, 7, 8 or 9 wire elements. In an assembly of the state of the art comprising at least 5 non-preformed wire elements, one of the wire elements is positioned in the center of the assembly. The invention advantageously makes it possible to solve this problem regardless of the number of wire elements of the assembly.

Preferably, the helix angle of at least each first and second wire element is between 10° and 25°. The helix angle is equal, in a projection plane of the helix through which its longitudinal axis passes, to the angle measured between the projection of the longitudinal axis on the projection plane and the tangent at the projection of the helix at the point of intersection of the projection of the helix and the projection of the longitudinal axis.

Preferably, the pitch P of the helix of at least each first and second wired element is such that P=k1.d in which d is the diameter of each first and second wired element with k1 ranging from 15 to 50. The helix pitch P is equal to the distance, along the axis of the wired element, that a point of the neutral fiber of the wired element travels after having traveled a complete revolution of the circle described by the neutral fiber.

Preferably, the diameter D of the helix of at least each first and second wired element is such that D=k2.d in which d is the diameter of each first and second wired element with k2 ranging from 2 to 5. The helix diameter D is equal to the diameter of the circle described by the neutral fiber F of each wire element. We can also determine the helix diameter D as being equal to the distance separating the centers of two diametrically opposed wire elements within the assembly A.

Such angles, pitch P and helix diameters D are compatible with use of the assembly in pneumatics.

In one embodiment, each first and second wired element consists of a single metallic elementary monofilament.

In another embodiment, each first and second wire element consists of a strand comprising several elementary metal monofilaments. Thus, for example, each wire element comprises a strand of several elementary monofilaments. Each strand preferably comprises one or more layers of elementary monofilaments wound together in a helix.

In these two embodiments, each elementary monofilament is preferably metallic. By metallic, is meant by definition an elementary monofilament consisting mainly (that is to say for more than 50% of its mass) or entirely (for 100% of its mass) of a metallic material. Each elementary monofilament is preferably made of steel, more preferably of pearlitic (or ferrito-pearlitic) carbon steel, hereinafter referred to as "carbon steel", or even stainless steel (by definition, steel comprising at least 10.5% of chromium).

When a carbon steel is used, its carbon content (% by mass of steel) is preferably between 0.5% and 0.9%. A steel of the steel cord type with normal resistance (called "NT" for "Normal Tensile") or high resistance (called "HT" for "High Tensile") is preferably used, the tensile strength (Rm) of which is preferably greater than 2000 MPa, more preferably greater than 2500 MPa and less than 3500 MPa (measurement carried out in tension according to ISO 6892-1 of 2009).

In a preferred embodiment, the diameter of the or each elementary monofilament ranges from 0.05 mm to 0.50 mm, preferably from 0.10 mm to 0.40 mm and more preferably from 0.15 mm to 0. 35mm.

The invention makes it possible to manufacture an assembly of wire elements wound together in a helix.

Advantageously, the assembly of wire elements has a structural elongation greater than or equal to 3.0%, preferably 4.0% and more preferably 5.0% measured according to standard ASTM A931-08.

The invention makes it possible to obtain a tire comprising an assembly of wire elements as defined above.

Such a tire is intended in particular to equip motor vehicles of the tourism type, SUV ( "Sport Utility Vehicles" ) , two wheels (in particular bicycles, motorcycles), airplanes, such as industrial vehicles chosen from vans, "heavyweight" - it i.e. metro, bus, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering machinery -, other transport or handling vehicles.

Preferably, the tire comprises a tread and a crown reinforcement arranged radially inside the tread. The crown reinforcement preferably comprises a working reinforcement and a protective reinforcement, the protective reinforcement being interposed radially between the tread and the working reinforcement. In a preferred embodiment, each protective ply comprising one or more reinforcing elements, called protective elements, each protective reinforcing element comprises an assembly as described above.

According to an optional characteristic of the tire, the protective reinforcing element or elements make an angle at least equal to 10°, preferably ranging from 10° to 35° and more preferably from 15° to 35° with the circumferential direction of the tire.

According to another optional characteristic of the tire, each working ply comprising reinforcing elements, called working, the working reinforcing elements make an angle at most equal to 60°, preferably ranging from 15° to 40° with the direction circumferential of the tire.

In a preferred embodiment, the crown reinforcement comprises a hooping reinforcement comprising at least one hooping ply. In a preferred embodiment, each hooping ply comprising one or more reinforcing elements, called hooping, each hooping element comprises an assembly as described above.

According to an optional characteristic of the tire, the hooping reinforcing element or elements make an angle at most equal to 10°, preferably ranging from 5° to 10° with the circumferential direction of the tire.

In a preferred embodiment, the carcass reinforcement is arranged radially inside the crown reinforcement.

Advantageously, the carcass reinforcement comprises at least one carcass ply comprising reinforcing elements, called carcass elements, the carcass reinforcing elements forming an angle greater than or equal to 65°, preferably 80° and more preferably ranging from 80° to 90° with respect to the circumferential direction of the tire.

• la figure 1 est un schéma d'une installation selon un premier mode de réalisation et permettant de mettre en œuvre un procédé selon un premier mode de réalisation et de fabriquer l'assemblage de la figure 2 ;
• la figure 2 est une vue en coupe perpendiculaire à l'axe de l'assemblage (supposé rectiligne et au repos) d'un assemblage fabriqué au moyen de l'installation de la figure 1;
• la figure 3 est une vue d'un fil de l'assemblage de la figure 2 projeté sur un plan parallèle à l'axe de l'assemblage ;
• la figure 4 est un schéma d'une installation selon un deuxième mode qui ne relève pas l'invention et n'est présent qu'à titre illustratif et permettant de mettre en œuvre un procédé de fabriquer l'assemblage de la figure 5 ;
• la figure 5 est une vue en coupe perpendiculaire à l'axe de l'assemblage (supposé rectiligne et au repos) d'un assemblage selon un mode qui ne relève pas l'invention et n'est présent qu'à titre illustratif fabriqué au moyen de l'installation de la figure 4 ;
• la figure 6 est un schéma d'une installation selon un troisième mode qui ne relève pas l'invention et n'est présent qu'à titre illustratif permettant de mettre en œuvre un procédé de fabriquer l'assemblage de la figure 7 ;
• la figure 7 est une vue en coupe perpendiculaire à l'axe de l'assemblage (supposé rectiligne et au repos) d'un assemblage selon un troisième mode qui ne relève pas l'invention et n'est présent qu'à titre illustratif fabriqué au moyen de l'installation de la figure 6.

The invention will be better understood on reading the following description, given solely by way of non-limiting example and made with reference to the drawings in which:

• the figure 1 is a diagram of an installation according to a first embodiment and making it possible to implement a method according to a first embodiment and to manufacture the assembly of the picture 2 ;
• the figure 2 is a cross-sectional view perpendicular to the axis of the assembly (assumed straight and at rest) of an assembly fabricated by means of the installation of the figure 1 ;
• the picture 3 is a view of a wire assembly of the figure 2 projected onto a plane parallel to the assembly axis;
• the figure 4 is a diagram of an installation according to a second mode which does not fall within the scope of the invention and is present only by way of illustration and making it possible to implement a method of manufacturing the assembly of the figure 5 ;
• the figure 5 is a cross-sectional view perpendicular to the axis of the assembly (assumed straight and at rest) of an assembly according to a mode which does not fall within the scope of the invention and is present only for illustrative purposes manufactured by means of the installing the figure 4 ;
• the figure 6 is a diagram of an installation according to a third mode which does not fall within the scope of the invention and is present only by way of illustration making it possible to implement a method of manufacturing the assembly of the figure 7 ;
• the figure 7 is a sectional view perpendicular to the axis of the joint (assumed rectilinear and at rest) of an assembly according to a third mode which is not part of the invention and is present only by way of illustration manufactured by means of the installation of the figure 6 .

We represented on the figure 1 an installation for manufacturing an assembly A of wire elements wound together in a helix. This installation, in accordance with the invention, is designated by the general reference 10.

• des moyens 12 d'alimentation de M éléments filaires 14,
• des moyens 16 de retordage individuel de chaque élément filaire 14 agencés de façon à retordre chaque élément filaire 14 séparément les uns des autres,
• des moyens 18 de préformation individuelle de chaque élément filaire 14 agencés en aval des moyens de retordage et de façon à préformer chaque élément filaire 14 retordu séparément les uns des autres,
• des moyens 20 d'assemblage des éléments filaires 14 ensemble en hélice pour former l'assemblage A agencés en aval des moyens de préformation et de façon à former l'assemblage d'éléments filaires,
• des moyens 24 d'entretien de la rotation de l'assemblage A autour de son axe,
• des moyens 26 d'équilibrage de l'assemblage A, et
• des moyens 28 de stockage de l'assemblage A.

The installation 10 comprises, from upstream to downstream considering the running direction of the wire elements:

• means 12 for supplying M wire elements 14,
• means 16 for individually twisting each wire element 14 arranged so as to twist each wire element 14 separately from each other,
• means 18 for individually preforming each wire element 14 arranged downstream of the twisting means and so as to preform each wire element 14 twisted separately from each other,
• means 20 for assembling the wire elements 14 together in a helix to form the assembly A arranged downstream of the preforming means and so as to form the assembly of wire elements,
• means 24 for maintaining the rotation of assembly A around its axis,
• means 26 for balancing the assembly A, and
• means 28 for storing assembly A.

The installation 10 also comprises means for guiding, unwinding and pulling the wire elements and the assembly conventionally used by those skilled in the art, for example pulleys and capstans.

The supply means 12 comprise a coil 30 for storing each wire element. For reasons of clarity of the figures, only two wire elements 14 have been shown therein and therefore only the corresponding means.

The means 16 for individually twisting each wire element 14 comprise a twister 32, also commonly called a “twister” by those skilled in the art, for example a twister with two pulleys.

The means 18 for individually preforming each wire element 14 comprise, for example, a roller preforming device 34 as described in US5533327A Where US4566261A .

The assembly means 20 comprise a distributor 36 and, downstream, an assembly grain 38.

The means 24 for maintaining the rotation are arranged downstream of the assembly grain 38 and comprise a twister 40, for example a twister with two pulleys making it possible to maintain the rotation of the assembly A respectively around the main direction of the rotation. assembly A.

Downstream of the means 24 for maintaining the rotation and the assembly grain 38, the assembly means 20 comprise a yoke 42 as well as a nacelle 44 carrying the balancing means 26 and the storage means 28. The yoke 42 and the nacelle 44 are rotatably mounted so as to impose the pitch of the assembly A.

The balancing means 26 comprise a twister 46, for example a twister with four pulleys.

The storage means 28 here comprise a coil 48 for storing assembly A.

We represented on the figures 2 and 3 the assembly A according to the first embodiment of the invention manufactured by means of the installation of the figure 1 .

Assembly A comprises, here consists of, a single layer 50 formed by the M wire elements of the assembly. The M wire elements are wound together in a helix. Layer 50 comprises between 2 and 9 wireframe elements 14. Here, layer 50 comprises, here consists of, M wireframe elements 14 (M=6). Assembly A of the picture 2 lacks a central core.

Each wire element 14 comprises, here consists of a single elementary metal monofilament of circular section, here in carbon steel, having a diameter ranging from 0.05 to 0.50 mm, preferably ranging from 0.10 mm to 0. 40 mm and preferably from 0.15 to 0.35 mm. here equal to 0.26 mm.

Assembly A has a structural elongation greater than or equal to 2.0% measured according to standard ASTM A931-08. Advantageously, it has a structural elongation greater than or equal to 3.0%, preferably 4.0% and more preferably 5.0% measured according to standard ASTM A931-08.

Each wire 14 is preformed by means of individual preforming means 18. Each wire 14 follows a trajectory having the shape of a three-dimensional helix characterized by a helix angle a, a helix pitch P and a helix diameter D.

As illustrated on the picture 3 , the helix angle a is equal, in a projection plane of the helix through which its longitudinal axis passes, to the angle measured between the projection of the longitudinal axis on the projection plane and the tangent to the helix projection at the point of intersection of the helix projection and the longitudinal axis projection. The helix angle a of each wire element 14 is between 10° and 25°.

As illustrated on the figures 2 and 3 , the helix diameter D is equal to the diameter of the circle described by the neutral fiber F of each wire element 14. It is also possible to determine the helix diameter D as being equal to the distance separating the centers of two diametrically opposed wire elements within the assembly A. The diameter D of the helix of each wire element 14 is such that D=k2.d in which d is the diameter of each wire element 14 with k2 ranging from 2 to 5.

As illustrated on the figures 2 and 3 , the helix pitch P is equal to the distance, along the axis of the wired element, that a point of the neutral fiber F of the wired element travels after having traveled a complete turn of the circle described by the neutral fiber F. The pitch P of the helix of at least each first and second wire element 14 is such that P=k1.d in which d is the diameter of each wire element 14 with k1 ranging from 15 to 50.

Assembly A is used in particular in tires and more preferably in tire protection or hooping plies as described previously.

We will now describe a method of manufacturing the assembly A according to a first embodiment, implemented by means of the installation 10.

First of all, the wire elements 14 are individually unwound from the supply means 12, here the coils 30.

Then, the method includes a step of individually twisting each wire element 14. Thus, each wire element 14 is twisted individually and separately from the others. The individual twisting step of the wire elements 14 is carried out thanks to the twisters 32. During this twisting step, each wire element 14 is subjected to a twist around its own axis, then each wire element 14 is balanced in torsion. After the individual twisting step, each wire element 14 is therefore twisted and balanced in torsion.

Next, the method comprises a step of individually preforming each filamentary element 14 previously twisted into a helix. Thus, each wire element 14 previously twisted is preformed individually and separately from the others. The individual preforming step of the wire elements 14 is carried out thanks to the preformers 34.

Then, the method comprises a step of assembling together the twisted and preformed wire elements 14 to form the assembly A of wire elements 14. The assembly step is carried out using the distributor 36, the assembly grain 38 but also thanks to the means arranged downstream of the assembly grain 38 which are the lyre 42 and the nacelle 44.

Then, the method comprises a step of maintaining the rotation of assembly A around its running direction. This maintenance step is carried out rotation thanks to the twister 40.

Then, the method also includes a step of balancing the assembly A. This balancing step is carried out downstream of the assembly step thanks to the twister 46.

Finally, assembly A is stored in storage reel 48.

We have illustrated on the figure 4 and 5 an installation and an assembly A in accordance with a second mode which is not part of the invention and is present only by way of illustration.

Items similar to those shown on the figures 1 to 3 are designated by identical references.

Unlike the first embodiment, the installation of the figure 4 further comprises means 12 for storing wire elements 14, means 50 for supplying a central core 15.

Thus, as illustrated in the figure 5 , the assembly A comprises, here consists, of a layer of M wire elements wound together in a helix around the central core 15 comprising N textile wire element(s) 17. The assembly A is here such that M=6 and N=1. As a variant, it could be provided that N>1, for example N=2 or 3.

Each textile thread element 17 here comprises several multifilament strands, each called a twist, each comprising several elementary monofilaments and assembled together in a helix to form a twist. The elementary monofilaments are textile, here in PET.

Unlike the method according to the first embodiment, the assembly step is a step of assembling the wire elements 14 and the central core 15. The assembly step is carried out so that the core central 15 has a substantially non-zero torsion. This torsion is substantially equal to the torsion imposed by the lyre 42, the supply means 50 being fixed with respect to the assembly grain 38.

We have illustrated on the figure 6 and 7 an installation and an assembly A in accordance with a third embodiment which does not fall within the scope of the invention and is present only by way of illustration. Elements similar to those shown in the preceding figures are designated by identical references.

Unlike the second embodiment, the installation of the figure 6 comprises, in addition to the means 50 for supplying the central core 15, means 52 for rotating the means 50. In this case, these means for rotation include a nacelle 54.

Thus, as illustrated in the figure 7 , the assembly A comprises, here consists, of a layer of M wire elements wound together in a helix around the central core 15 comprising N metal wire element(s) 17. The assembly A is here such that M=6 and N=1. As a variant, it could be provided that N>1, for example N=2 or 3.

Each metallic wire element 17 is here an elementary metallic monofilament, for example a steel wire with a diameter of between 0.05 mm and 0.50 mm, here equal to 0.20 mm.

Unlike the method according to the second embodiment, the assembly step is performed so that the central core 15 has substantially zero torsion. This substantially zero torsion is obtained by synchronizing the rotation of the lyre 42 and the rotation of the supply means 50.

The invention is not limited to the embodiments described above.

Indeed, it is possible to envisage exploiting the invention with wire elements each comprising several elementary metallic monofilaments. Each wire element then consists of a strand comprising the elementary metal monofilaments. Once assembled, the wire elements or strands form a multi-strand cable.

Claims (7)

1. Unit for producing an assembly (A) of filamentary elements (14) wound together in a helix, characterized in that it comprises:

   - means (16) of twisting at least first and second filamentary elements (14), arranged in such a way as to twist the first and second filamentary elements (14) separately from one another in such a way that each filamentary element (14) is plastically deformed,

   - means (18) of preforming at least the first and second twisted filamentary elements (14) into a helix, arranged downstream of the twisting means and so as to preform the twisted first and second filamentary elements (14) separately from one another,

   - means (20) of assembling at least the first and second twisted and preformed filamentary elements (14), arranged downstream of the preforming means and in such a way as to form the assembly (A) of filamentary elements (14); in which the assembly (A) of filamentary elements (14) comprises a single layer (50) formed by the filamentary elements (14) of the assembly (A).
2. Unit according to Claim 1, in which the assembly means (20) comprise a distributor (36) and an assembly guide (38).
3. Unit according to the preceding claim, comprising means (24) of maintaining the rotation of the assembly (A) which are arranged downstream of the assembly guide (38).
4. Unit according to Claim 2 or 3, in which the means of assembly comprise a bow (42) positioned downstream of the assembly guide (38).
5. Unit according to any one of Claims 2 to 4, in which the means of assembly (20) comprise a pod (44) arranged downstream of the assembly guide (38) bearing means (28) of storing the assembly (A).
6. Unit according to the preceding claim, in which the pod (44) bears means (26) of balancing the assembly (A).
7. Unit according to any one of the preceding claims, comprising means (12) of feeding at least the first and second filamentary elements (14) arranged upstream of the twisting means (16).

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