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EP0833994A1 - Multilayer cable sheath, method for making same and machine therefor - Google Patents

Multilayer cable sheath, method for making same and machine therefor

Info

Publication number
EP0833994A1
EP0833994A1 EP96922920A EP96922920A EP0833994A1 EP 0833994 A1 EP0833994 A1 EP 0833994A1 EP 96922920 A EP96922920 A EP 96922920A EP 96922920 A EP96922920 A EP 96922920A EP 0833994 A1 EP0833994 A1 EP 0833994A1
Authority
EP
European Patent Office
Prior art keywords
sheath
strips
plastic
strip
assembly
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP96922920A
Other languages
German (de)
French (fr)
Inventor
Pierre Boitel
Michel Cornu
Carlos De La Fuente
Jean-François Nieto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Freyssinet International STUP SA
Original Assignee
Freyssinet International STUP SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Freyssinet International STUP SA filed Critical Freyssinet International STUP SA
Publication of EP0833994A1 publication Critical patent/EP0833994A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
    • E04C5/08—Members specially adapted to be used in prestressed constructions
    • E04C5/10—Ducts

Definitions

  • the present invention relates to a cable sheath, in particular a prestressing sheath or a shroud sheath, its manufacturing process and the machine for implementing said process.
  • Prestressing ducts which are intended to be embedded in concrete structures and to receive the prestressing cables of these structures, must meet several requirements:
  • these plastic sheaths generally have, as protruding relief, grooves on their outer surface. These corrugations do not make it possible to fix sheath fittings by screwing.
  • threaded portions are generally provided at the ends of the sheaths, these threaded portions generally being produced by molding.
  • this implementation prevents the sizing on site of these sheaths to any desired length.
  • special sleeves are provided, in the form of half-shells which are assembled after the installation of the sheaths. This implementation also causes an increase in manufacturing costs.
  • plastic sleeves Another disadvantage of plastic sleeves is that it is difficult to find a plastic material which simultaneously fulfills all the above-mentioned requirements.
  • the present invention aims to provide a cable sheath meeting the above requirements by eliminating the aforementioned drawbacks.
  • the present invention therefore aims to provide an improved cable sheath which is waterproof and resistant, which has a minimum wall thickness, which has low friction inside, and which can effect the transfer of the prestressing forces to the concrete. .
  • the present invention aims to provide an improved cable sheath which has a structure such that the above requirements are each optimally fulfilled.
  • the present invention also aims to provide such an improved cable sheath, the manufacture of which is simple, rapid and economical.
  • the present invention also aims to provide such an improved cable sheath which can be manufactured in situ at any desired length.
  • the present invention also aims to provide such an improved cable sheath made essentially of plastic.
  • the present invention therefore relates to a cable sheath comprising a multi-layer structure comprising at least two continuous superimposed layers of plastic material, each consisting of a strip arranged in a helix and the lateral edges of which are respectively joined with tight junctions.
  • This multi-layer structure has many advantages. Thus, it is possible to easily vary the thickness of the wall of the sheath by modifying the number of layers, these may each have very small thicknesses, which largely eliminates the winding difficulties due to memory. shape of plastics. On the other hand, it is possible to incorporate layers of different materials, each layer having particular properties.
  • the multi-layer structure can comprise more than two plastic layers.
  • the invention provides a cable sheath made entirely of plastic.
  • said at least two plastic layers are welded to each other at at least one point, advantageously along a line, for example by thermal welding. This characteristic makes it possible to make irreversible connections between the layers and guarantees repeatability and homogeneity of the sheath.
  • the cable sheath has on its outer surface at least one continuous helical thread.
  • the presence of the helical thread or continuous spiral makes it possible to fix duct fittings by simple screwing.
  • the fact that the thread extends continuously over the entire sheath makes it possible to cut the latter to any desired length.
  • the rigidity of the sheath can be modified.
  • an insert such as a metal wire, is arranged in the multi-layer structure of the sheath, in particular in at least one longitudinal rib of at least one strip.
  • This insert can act to reinforce the rigidity of the sheath or possibly be a heating insert.
  • a particularly suitable use of the sheath according to the invention is the use as a prestressing sheath.
  • the sheath according to the invention can also be used as a shroud sheath.
  • the advantageous presence of a continuous spiral net on the outer surface of the sheath has in this case aerodynamic advantages with respect to the wind as well as rainwater which can flow more easily by being channeled, and the multilayer structure makes it possible to produce an outer layer having any practical or aesthetic characteristic desired.
  • the present invention further relates to a method of manufacturing a cable sheath, comprising the following steps:
  • the method comprises the step of welding at least one point said at least two superimposed layers of plastic.
  • this welding is carried out thermally along a continuous helical line, which provides improved sealing of the sheath.
  • the method comprises, before the step of assembling, of forming at least one longitudinal rib in each strip.
  • the invention further relates to a machine for implementing the method comprising at least two reels for receiving strip rolls to supply said at least two strips, and an assembly device for assembling the strips in a helical manner so their respective lateral edges are joined.
  • the assembly device comprises a fixed cylindrical mandrel, which may comprise at least one continuous spiral thread on its outer surface, on which a respective longitudinal rib of each strip formed is wound helically. beforehand by means of a corresponding rib forming module, the winding being advantageously carried out by means of driving rollers and / or pressers.
  • the assembly device comprises two rotary cylindrical mandrels, around which the strips are wound in a helix, the assembly formed by said two rotary mandrels being itself rotary.
  • the winding is also advantageously carried out by means of driving rollers and / or pressers.
  • This variant makes it possible to produce ducts of oblong cross section.
  • FIG. 1 is a schematic view in longitudinal section of the wall of a sheath with a multi-layer structure according to the invention
  • FIG. 2 represents a part of the assembly device according to the invention and schematically illustrates the manner in which the sheath with a multi-layer structure according to the invention is assembled
  • FIG. 3 is a schematic view of a machine for implementing the method of manufacturing a sheath with a multi-layer structure according to the invention, said machine incorporating a first variant of the assembly device
  • Figure 4 is a view similar to Figure 3, the machine incorporating a second variant of the assembly device.
  • the sheath 1 comprises a multi-layer structure which can for example comprise three superimposed layers 10a, 10b, 10c.
  • the number of layers 10 which is at least two is not limited and the embodiment of the sheath comprising three layers as shown in the figures only represents an advantageous embodiment.
  • the three-layer structure is advantageous when the sheath is used as a prestressing sheath because, to obtain the minimum wall thickness required, that is to say approximately 2 millimeters before the cables are tensioned, it is possible to in this case use layers of material having a standard thickness of about 0.7 millimeter.
  • the thickness of the wall may be less or more, and the number of layers may therefore be different.
  • the sheath with a multi-layer structure comprises at least one layer of plastic material.
  • said sheath comprises at least two layers of superimposed plastic material, which makes it possible to bind them intimately together as will be explained later on in the description of the process for manufacturing the sheath.
  • sheath with a multi-layer structure comprising three layers 10a, 10b, 10c made of plastic, but it is clear that the sheath may comprise a layer made of a other material, such as fiberglass or metal, for example.
  • a particularly advantageous characteristic of the sheath with a multi-layer structure of the present invention lies in the possibility of choosing each layer in a particular material having particular intrinsic characteristics, so that each layer of the multi-layer structure fills a special function.
  • the layer 10a located inside the sheath can be made of a material which has a low friction during the tensioning of the prestressing cables, for example Teflon or graphite high density polyethylene (HDPE).
  • the second layer 10b that is to say the one which is directly superimposed on said first inner layer 10a, can for example be made of a material having a relatively high rigidity.
  • the outer layer 10c can be made of a material having characteristics of good resistance to ultraviolet rays.
  • This multi-layer structure also allows the cable sheath according to the invention to be suitable for other uses than that of prestressing sheath.
  • a sheath can be used as a shroud sheath.
  • the characteristics required for the inner 10a and outer 10c layers of the sheath are not necessarily the same as those of a prestressing sheath, it is then possible to choose different materials for the layers constituting said sheath.
  • the outer layer 10c can for example be made of a colored material to meet aesthetic requirements, said colored material also having good resistance to ultraviolet rays to guarantee good hold. in colour.
  • each layer 10 of the sheath is continuous, that is to say that each layer of the sheath forms a closed sleeve 10, the multi-layer structure therefore being a superposition of several of these individual sleeves 10a , 10b, 10c.
  • each layer 10 of the sheath is formed from a strip or strip of material 11, which is assembled in such a way that its lateral edges 12, 13 are contiguously adjacent to form said sleeve.
  • said lateral edges 12a, 13a; 12b, 13b; 12c, 13c of each strip l ia, l lb, 1 le of plastic material, which are contiguously adjacent after their assembly, are thermally welded together to form a layer of sheath of homogeneous and waterproof plastic.
  • these zones of thermal welding 17 of the lateral edges of each plastic strip are offset from one layer to the other axially along the sheath 1. This additionally ensures perfect sealing of the multi-layer structure of the sheath, these zones 17 of relatively weak sealing of the different layers of sheath not being located opposite one another.
  • the sheath 1 has on its outer surface at least one continuous helical or spiral thread 15.
  • This spiral thread 15 acts in particular to fulfill the above-mentioned requirement for transfer of forces to concrete, after hardening cement grout.
  • this continuous spiral thread 15 outside the sheath is formed by one or more longitudinal ribs 14a, 14b, 14c formed in each strip l ia, llb, the ie constituting said multi-layer structure.
  • Said longitudinal ribs 14a, 14b, 14c of the different strips are preferably equidistant so as to be superposed on each other during the assembly of said sheath.
  • each strip 1a, 1lb are preferably equidistant so as to be superposed on each other during the assembly of said sheath.
  • the sheath 1 therefore has on its outer surface three continuous helical threads 15. This characteristic is particularly advantageous when the sheath has a circular cross section, because it allows the fitting of sheath fittings by simple screwing on said threads. spirals 15, at the ends of the sheath 1.
  • the width of the different strips l ia, l lb, l ie forming the multi-layer structure as well as the number and / or the distance between the longitudinal ribs 14a, 14b, 14c formed in each of said strips l ia, l lb, l ie can be variable, which advantageously makes it possible to modulate the rigidity of said sheath 1.
  • an insert 19 is arranged in the multi-layer structure of the sheath.
  • This insert 19, which may for example be a metal wire, can serve to further strengthen the rigidity of said sheath, but it can also act as a heating insert by passing an electric current through it.
  • said insert 19 acts to heat the sheath in the event of an extremely low temperature, thus making it possible to inject the cement slurry even in cold weather.
  • This insert or metal wire is advantageously disposed in one or more of said longitudinal ribs 14a, 14b, 14c of one or more of said strips 11a, 11b, 1e. In this case, it extends over the entire length of the sheath in a spiral manner.
  • the sheath according to the invention can have a circular cross section, but it can also have a different cross section and in particular oblong, as visible in FIG. 4. This implementation ensures, in certain applications, a better distribution of prestressing forces, especially in thin structures.
  • the invention also relates to the method of manufacturing a sheath with a multi-layer structure as described above.
  • This method essentially comprises assembling in a spiral by superimposing said strips by means of an assembly device 20. The assembly is carried out so that the respective lateral edges of each strip are joined to form continuous sheath layers .
  • at least one of said strips l ia, l lb, l ie is made of plastic and according to a preferred aspect of the manufacturing process, at least two of said strips l ia, l lb, l ie are made of plastic to form at least two superimposed layers of plastic in the multi-layer structure of the sheath.
  • Each strip l ia, l l b, 1 le is fed from a roll or a reel
  • rib forming in which at least one longitudinal rib 14a, 14b, 14c is respectively formed in said strip l ia, l lb, 1 le.
  • modules 40 are adapted to form ribs 14a, 14b, 14c which are identical in the different strips constituting the multi-layer structure and advantageously include heating means making it possible to deform the material to form said ribs l ia, llb, linked in each strip respective.
  • Said strips 11a, 11b, 1 constituting the multilayer structure are then assembled, preferably simultaneously as visible in FIGS. 3 and 4, by means of an assembly device 20. This assembly is preferably carried out by winding in spiral each of said strips so that their longitudinal ribs 1a, 1lb, 1 are superimposed. Said strips thus form the different layers 10a, 10b, 10c of the multi-layer structure of the sheath.
  • said assembly device 20 comprises a fixed cylindrical mandrel 21 which in this example comprises at least one continuous helical or spiral thread 22 on its outer surface.
  • the assembly device 20 is suitable for assembling a sheath with a multi-layer structure having a substantially circular cross section.
  • the mandrel 21 comprises a continuous spiral thread 22 for each longitudinal rib 14a, 14b, 14c of the different strips l ia, l lb, Uc.
  • the strips each have three longitudinal ribs as well as the mandrel.
  • each of said longitudinal ribs 14a, 14b, 14c of each of said strips comes to engage on a respective spiral thread 22 of the mandrel 21, during assembly.
  • This assembly is advantageously done by helically winding said strips around said mandrel 21. As visible in FIG. 3, this winding is preferably carried out by means of driving rollers 25 which are advantageously arranged in an inclined manner to follow said continuous spiral threads 22 of mandrel 21 and which are rotated by a suitable device 26.
  • These rollers 25 act in particular to guide the strips so that their longitudinal ribs 14a, 14b, 14c engage on said spiral threads 22 of the mandrel 21.
  • Each strip l ia, llb, l ie therefore wraps around said mandrel 21 to form a layer 10a, 10b, 10c of the multi-layer structure of the sheath 1, this winding being carried out in such a way that the lateral edges 12a, 13a; 12b, 13b; 12c, 13c of each strip 1a, llb, lie are adjacent to each other in a contiguous manner after winding around said mandrel 21.
  • Figure 2 in which we also see that the winding of three strips 1 la, l lb, l ie is produced in such a way that these overlap with their lateral edges offset axially.
  • the method advantageously provides for having a heating module 30 for each strip of plastic material, intended in particular to heat its lateral edges 12a, 13a; 12b, 13b; 12c, 13c.
  • a heating module 30 for each strip of plastic material, intended in particular to heat its lateral edges 12a, 13a; 12b, 13b; 12c, 13c.
  • the adjacent heated edges of each plastic strip are thermally welded together by means of said drive rollers 25 which, in this case, also act as pressure rollers. This characteristic makes it possible to obtain with each plastic strip a tight and homogeneous plastic layer.
  • each of said heating modules 30 is further intended to locally heat so-called melting zones 18 in each strip so that, during winding, said respective heated zones 18 of two strips, which overlap during said winding , are pressed against each other by means of said pressure rollers 25, so that said superimposed layers formed by said two strips are intimately linked in these melting zones 18.
  • melting zones 18 in each strip so that, during winding, said respective heated zones 18 of two strips, which overlap during said winding , are pressed against each other by means of said pressure rollers 25, so that said superimposed layers formed by said two strips are intimately linked in these melting zones 18.
  • the spiral ribs no longer serve to ensure the transfer of the forces to the concrete. We can then dispense with it. Note, however, that these ribs participate in obtaining good rigidity of the sheath.
  • Figure 4 is shown a second variant of the assembly device 20 described above.
  • the assembly device 20 does not include a fixed mandrel, but two rotary cylindrical mandrels 23a, 23b which may each include one or more continuous spiral threads (not shown) on their outer surface.
  • the assembly formed by said two rotary mandrels 23a and 23b is itself rotary around an axis.
  • the strips are wound around said two mandrels 23a, 23b to form a sheath with a multi-layer structure having an oblong cross section.
  • the sheath with a multi-layer structure advantageously passes through a cooling module 60 in order to freeze the shape of said sheath 1. Since the heating modules 30 only act locally, that is to say on the lateral edges and in particular melting zones of each strip, this cooling is not essential and in any case does not need to be particularly important. Then, the sheath with a multi-layer structure preferably passes through a cutting module 70 in which said sheath is cut to any desired length.
  • the manufacturing process described above therefore has very significant advantages which are:
  • the sheath obtained has a multi-layer structure, which implies the advantages mentioned above, namely in particular that according to the desired characteristics, the number of layers and / or the material of the strips constituting the layers can be modified very simply.
  • the machine for implementing this process is simple and space-saving and therefore allows manufacturing on site, that is to say on site, of the sheath with a multilayer structure of the invention.
  • the sheath obtained with this process may include one or more continuous spiral threads on its outer surface which allows sheath connections to be made by simply screwing in suitable sleeves, whatever the desired length of the sheath.
  • the cutting module makes it possible to cut the sheath obtained to any desired length.
  • the fact that this process can be implemented on site possibly makes it possible to produce ducts of great length, which is impossible when the ducts have to be transported from the factory to the site.
  • the machine for implementing the process for manufacturing the sheath according to the invention also makes it possible to carry out said sites on site. connection sleeves which are screwed onto the ends of said sheaths to connect the latter.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Insulated Conductors (AREA)
  • Laminated Bodies (AREA)
  • Manufacturing Of Electric Cables (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)

Abstract

A cable sheath (1) with a multilayer structure comprising at least two continuous stratified plastic layers (10a, 10b) each consisting of a helical strip (11a, 11b) with respective contiguous side edges (12a, 13a; 12b, 13b) sealed together.

Description

GAINE DE CABLE A STRUCTURE MULTI-COUCHE, SON PROCEDE DE FABRICATION ET MACHINE POUR METTRE EN OEUVRE CE PROCEDE MULTI-LAYERED CABLE SHEATH, MANUFACTURING METHOD THEREOF, AND MACHINE FOR CARRYING OUT SAID METHOD
La présente invention concerne une gaine de câble, notamment une gaine de précontrainte ou une gaine de hauban, son procédé de fabrication et la machine pour mettre en œuvre ledit procédé.The present invention relates to a cable sheath, in particular a prestressing sheath or a shroud sheath, its manufacturing process and the machine for implementing said process.
Les gaines de précontrainte, qui sont destinées à être noyées dans des ouvrages en béton et à recevoir les câbles de précontrainte de ces ouvrages, doivent répondre à plusieurs exigences :Prestressing ducts, which are intended to be embedded in concrete structures and to receive the prestressing cables of these structures, must meet several requirements:
- elles doivent satisfaire à certaines caractéristiques d'étanchéité à l'eau,- they must meet certain waterproof characteristics,
- elles doivent avoir une forte résistance à l'abrasion et aux contraintes mécaniques, - elles doivent avoir une épaisseur de paroi minimale pour éviter d'être percées lors de la mise en tension des câbles,- they must have a high resistance to abrasion and to mechanical stresses, - they must have a minimum wall thickness to avoid being pierced during the tensioning of the cables,
- elles doivent assurer un faible frottement lors de la mise en tension des câbles,- they must ensure low friction when tensioning the cables,
- elles doivent permettre le transfert des forces de précontrainte à la structure par l'intermédiaire du coulis de ciment durci, injecté postérieurement à la mise en tension, en comportant un relief sur leur surface extérieure.- They must allow the transfer of the prestressing forces to the structure via the hardened cement grout, injected after the tensioning, with a relief on their outer surface.
Il est connu de réaliser des gaines de précontrainte en métal, notamment en acier. Une technique simple consiste à enrouler en hélice un feuillard métallique, en agrafant les bords du feuillard adjacents après l'enroulement. Cette technique présente l'avantage de réaliser une gaine pouvant comporter une nervure spiralée sur sa surface extérieure permettant de fixer des raccords de gaines par simple vissage aux extrémités desdites gaines. Toutefois, ces gaines métalliques présentent l'inconvénient de rouiller facilement, ce qui peut entraîner des détériorations locales et donc des pertes d'étanchéité et/ou de solidité. Pour surmonter cet inconvénient, il est possible de revêtir le feuillard métallique d'une couche de protection, ce qui augmente toutefois considérablement le coût de fabrication.It is known to produce prestressing sheaths in metal, in particular in steel. A simple technique consists of winding a metal strip helically, stapling the edges of the adjacent strip after winding. This technique has the advantage of producing a sheath which may have a spiral rib on its outer surface making it possible to fix sheath fittings by simple screwing at the ends of said sheaths. However, these metal sheaths have the disadvantage of rusting easily, which can cause local deterioration and therefore loss of tightness and / or solidity. To overcome this drawback, it is possible to coat the metal strip with a protective layer, which however considerably increases the manufacturing cost.
Une autre solution pour surmonter cet inconvénient est de réaliser des gaines en plastique. Toutefois, en raison de l'épaisseur minimale de paroi de gaine requise (environ 2 millimètres) et de la mémoire de forme des matières plastiques appropriées, pour pouvoir utiliser le procédé de fabrication des gaines métalliques mentionné ci-dessus, il faut chauffer l'ensemble du feuillard en plastique, l'enrouler, souder les bords adjacents et refroidir la gaine rapidement, ce qui est long et implique un coût énergétique très élevé. Ce procédé de fabrication est par conséquent trop coûteux et ne peut pas être réalisé in situ, c'est-à-dire sur le chantier. Il est par conséquent nécessaire de fabriquer ces gaines en plastique, par exemple par extrusion ou moulage, dans des machines compliquées et coûteuses et de les transporter sur le chantier à partir du lieu de fabrication, ce qui est- également très coûteux, notamment à cause de leur volume encombrant. D'autre part, un transport des gaines empêche de réaliser des gaines de grandes dimensions en longueurs droites.Another solution to overcome this drawback is to produce plastic sheaths. However, due to the minimum sheath wall thickness required (about 2 millimeters) and the shape memory of the appropriate plastics, in order to be able to use the manufacturing process of the metal sheaths mentioned above, it is necessary to heat the whole plastic strip, wind it, weld the adjacent edges and cool the sheath quickly, which is long and involves a very high energy cost. This manufacturing process is therefore too expensive and cannot be carried out in situ, that is to say on the site. It is therefore necessary to manufacture these plastic sheaths, for example by extrusion or molding, in complicated and expensive machines and to transport them to the site from the place of manufacture, which is also very expensive, in particular because of their bulky volume. On the other hand, transporting the sheaths prevents the production of large sheaths in straight lengths.
Par ailleurs, ces gaines en plastique comportent généralement, en tant que relief saillant, des annelures sur leur surface extérieure. Ces annelures ne permettent pas de fixer des raccords de gaine par vissage. Pour surmonter cet inconvénient, on prévoit généralement des parties filetées aux extrémités des gaines, ces parties filetées étant généralement réalisées par moulage. Outre la hausse des coûts de fabrication, cette mise en œuvre empêche le dimensionnement sur le chantier de ces gaines à une longueur quelconque souhaitée. Alternativement, on prévoit des manchons spéciaux, en forme de demi-coquilles qui sont assemblés après la pose des gaines. Cette mise en œuvre provoque également une hausse des coûts de fabrication.Furthermore, these plastic sheaths generally have, as protruding relief, grooves on their outer surface. These corrugations do not make it possible to fix sheath fittings by screwing. To overcome this drawback, threaded portions are generally provided at the ends of the sheaths, these threaded portions generally being produced by molding. In addition to the increase in manufacturing costs, this implementation prevents the sizing on site of these sheaths to any desired length. Alternatively, special sleeves are provided, in the form of half-shells which are assembled after the installation of the sheaths. This implementation also causes an increase in manufacturing costs.
Il existe des machines pour fabriquer par extrusion des gaines en plastique comportant un filet spirale sur leur surface extérieure. Ces machines sont toutefois très compliquée et très coûteuse et ne peuvent pas être utilisées in situ. Les inconvénients précités ne sont donc pas éliminés.There are machines for making plastic sleeves by extrusion with a spiral thread on their outer surface. These machines are however very complicated and very expensive and cannot be used in situ. The aforementioned drawbacks are therefore not eliminated.
Un autre inconvénient des gaines en plastique est qu'il est difficile de trouver un matériau plastique remplissant simultanément toutes les exigences susmentionnées.Another disadvantage of plastic sleeves is that it is difficult to find a plastic material which simultaneously fulfills all the above-mentioned requirements.
La présente invention a pour but de fournir une gaine de câble répondant aux exigences susmentionnés en éliminant les inconvénients précités.The present invention aims to provide a cable sheath meeting the above requirements by eliminating the aforementioned drawbacks.
La présente invention a donc pour but de fournir une gaine de câble améliorée qui est étanche et résistante, qui a une épaisseur de paroi minimale, qui présente un faible frottement à l'intérieur, et qui peut réaliser le transfert des forces de précontrainte au béton. En particulier, la présente invention a pour but de fournir une gaine de câble améliorée qui a une structure telle que les exigences précitées soient chacune remplies de manière optimale.The present invention therefore aims to provide an improved cable sheath which is waterproof and resistant, which has a minimum wall thickness, which has low friction inside, and which can effect the transfer of the prestressing forces to the concrete. . In particular, the present invention aims to provide an improved cable sheath which has a structure such that the above requirements are each optimally fulfilled.
La présente invention a également pour but de fournir une telle gaine de câble améliorée dont la fabrication est simple, rapide et économique.The present invention also aims to provide such an improved cable sheath, the manufacture of which is simple, rapid and economical.
La présente invention a encore pour but de fournir une telle gaine de câble améliorée pouvant être fabriquée in situ à une longueur quelconque souhaitée.The present invention also aims to provide such an improved cable sheath which can be manufactured in situ at any desired length.
La présente invention a encore pour but de fournir une telle gaine de câble améliorée réalisée essentiellement en matière plastique.The present invention also aims to provide such an improved cable sheath made essentially of plastic.
La présente invention a donc pour objet une gaine de câble comportant une structure multi-couche comportant au moins deux couches continues superposées en matériau plastique, constituée chacune d'un feuillard disposé en hélice et dont les bords latéraux sont respectivement jointifs avec jonctions étanches. Cette structure multi-couche implique de nombreux avantages. Ainsi, il est possible de varier aisément l'épaisseur de la paroi de la gaine en modifiant le nombre de couches, celles-ci pouvant avoir chacune des épaisseurs très faibles, ce qui élimine en grande partie les difficultés d'enroulement dues à la mémoire de forme des matières plastiques. D'autre part, il est possible d'incorporer des couches de matières différentes, chaque couche ayant des propriétés particulières.The present invention therefore relates to a cable sheath comprising a multi-layer structure comprising at least two continuous superimposed layers of plastic material, each consisting of a strip arranged in a helix and the lateral edges of which are respectively joined with tight junctions. This multi-layer structure has many advantages. Thus, it is possible to easily vary the thickness of the wall of the sheath by modifying the number of layers, these may each have very small thicknesses, which largely eliminates the winding difficulties due to memory. shape of plastics. On the other hand, it is possible to incorporate layers of different materials, each layer having particular properties.
La structure multi-couche peut comporter plus de deux couches en matière plastique. En particulier, l'invention fournit une gaine de câble entièrement en matière plastique. De préférence, lesdites au moins deux couches en matière plastique sont soudées l'une à l'autre en au moins un point, avantageusement suivant une ligne, par exemple par soudure thermique. Cette caractéristique permet de réaliser des liaisons irréversibles entre les couches et garantit une répétabilité et une homogénéité de la gaine.The multi-layer structure can comprise more than two plastic layers. In particular, the invention provides a cable sheath made entirely of plastic. Preferably, said at least two plastic layers are welded to each other at at least one point, advantageously along a line, for example by thermal welding. This characteristic makes it possible to make irreversible connections between the layers and guarantees repeatability and homogeneity of the sheath.
De préférence, la gaine de câble comporte sur sa surface extérieure au moins un filet hélicoïdal continu. La présence du filet hélicoïdal ou spirale continu permet de fixer des raccords de gaine par simple vissage. De plus, le fait que le filet s'étend en continu sur toute la gaine permet de couper celle-ci à une longueur quelconque souhaitée. En outre, selon le pas dudit filet spirale, la rigidité de la gaine peut être modifiée.Preferably, the cable sheath has on its outer surface at least one continuous helical thread. The presence of the helical thread or continuous spiral makes it possible to fix duct fittings by simple screwing. In addition, the fact that the thread extends continuously over the entire sheath makes it possible to cut the latter to any desired length. In addition, depending on the pitch of said spiral net, the rigidity of the sheath can be modified.
Selon un aspect de l'invention, un insert, tel qu'un fil métallique, est disposé dans la structure multi-couche de la gaine, notamment dans au moins une nervure longitudinale d'au moins un feuillard. Cet insert peut agir pour renforcer la rigidité de la gaine ou éventuellement être un insert chauffant.According to one aspect of the invention, an insert, such as a metal wire, is arranged in the multi-layer structure of the sheath, in particular in at least one longitudinal rib of at least one strip. This insert can act to reinforce the rigidity of the sheath or possibly be a heating insert.
Une utilisation particulièrement appropriée de la gaine selon l'invention est l'utilisation en tant que gaine de précontrainte. Toutefois, la gaine selon l'invention peut aussi être utilisée en tant que gaine de hauban. La présence avantageuse d'un filet spirale continu sur la surface extérieure de la gaine présente dans ce cas des avantages aérodynamiques vis-à-vis du vent ainsi que de l'eau de pluie qui peut s'écouler plus facilement en étant canalisée, et la structure multi- couche permet de réaliser une couche extérieure présentant toute caractéristique pratique ou esthétique souhaitée.A particularly suitable use of the sheath according to the invention is the use as a prestressing sheath. However, the sheath according to the invention can also be used as a shroud sheath. The advantageous presence of a continuous spiral net on the outer surface of the sheath has in this case aerodynamic advantages with respect to the wind as well as rainwater which can flow more easily by being channeled, and the multilayer structure makes it possible to produce an outer layer having any practical or aesthetic characteristic desired.
La présente invention a en outre pour objet un procédé de fabrication d'une gaine de câble, comprenant les étapes suivantes :The present invention further relates to a method of manufacturing a cable sheath, comprising the following steps:
- fournir au moins deux feuillards en matière plastique,- provide at least two plastic straps,
- assembler en hélice, en les superposant au moyen d'un dispositif d'assemblage, chacun desdits feuillards, de telle sorte que ses bords latéraux respectifs soient jointifs pour former une gaine à structure multi-couche comportant au moins deux couches en plastique.- Assemble in a helix, by superimposing them by means of an assembly device, each of said strips, so that its respective lateral edges are joined to form a sheath with a multi-layer structure comprising at least two plastic layers.
De préférence, le procédé comporte l'étape de souder en au moins un point lesdites au moins deux couches superposées en matière plastique. Avantageusement, cette soudure est réalisée thermiquement le long d'une ligne continue en hélice, ce qui fournit une étanchéité améliorée de la gaine.Preferably, the method comprises the step of welding at least one point said at least two superimposed layers of plastic. Advantageously, this welding is carried out thermally along a continuous helical line, which provides improved sealing of the sheath.
De préférence, le procédé comporte, avant l'étape d'assembler, de former au moins une nervure longitudinale dans chaque feuillard.Preferably, the method comprises, before the step of assembling, of forming at least one longitudinal rib in each strip.
L'invention a en outre pour objet une machine pour mettre en œuvre le procédé comprenant au moins deux bobines pour recevoir des rouleaux de feuillard pour fournir lesdits au moins deux feuillards, et un dispositif d'assemblage pour assembler les feuillards en hélice de telle sorte que leurs bords latéraux respectifs soient jointifs.The invention further relates to a machine for implementing the method comprising at least two reels for receiving strip rolls to supply said at least two strips, and an assembly device for assembling the strips in a helical manner so their respective lateral edges are joined.
Selon une première variante de l'invention, le dispositif d'assemblage comporte un mandrin cylindrique fixe, qui peut comporter au moins un filet spirale continu sur sa surface extérieure, sur lequel vient s'enrouler en hélice une nervure longitudinale respective de chaque feuillard formé prélablement au moyen d'un module de formage de nervure correspondant, l'enroulement étant réalisé avantageusement au moyen de galets entraîneurs et/ou presseurs. Cette variante permet de réaliser des gaines de section transversale sensiblement circulaires. Selon une seconde variante de l'invention, le dispositif d'assemblage comporte deux mandrins cylindriques rotatifs, autour desquels viennent s'enrouler en hélice les feuillards, l'ensemble formé par lesdits deux mandrins rotatifs étant lui-même rotatif.According to a first variant of the invention, the assembly device comprises a fixed cylindrical mandrel, which may comprise at least one continuous spiral thread on its outer surface, on which a respective longitudinal rib of each strip formed is wound helically. beforehand by means of a corresponding rib forming module, the winding being advantageously carried out by means of driving rollers and / or pressers. This variant makes it possible to produce substantially circular cross-section sheaths. According to a second variant of the invention, the assembly device comprises two rotary cylindrical mandrels, around which the strips are wound in a helix, the assembly formed by said two rotary mandrels being itself rotary.
L'enroulement est également réalisé avantageusement au moyen de galets entraîneurs et/ou presseurs. Cette variante permet de réaliser des gaines de section transversale oblongue.The winding is also advantageously carried out by means of driving rollers and / or pressers. This variant makes it possible to produce ducts of oblong cross section.
D'autres caractéristiques et avantages apparaîtront au cours de la description détaillée suivante, donnée à titre d'exemple non limitatif, en regard des dessins joints, sur lesquels : la figure 1 est une vue schématique en coupe longitudinale de la paroi d'une gaine à structure multi-couche selon l'invention, la figure 2 représente une partie du dispositif d'assemblage selon l'invention et illustre schématiquement la manière dans laquelle la gaine à structure multi- couche selon l'invention est assemblée, la figure 3 est une vue schématique d'une machine pour mettre en œuvre le procédé de fabrication d'une gaine à structure multi-couche selon l'invention, ladite machine incorporant une première variante du dispositif d'assemblage, et la figure 4 est une vue similaire à la figure 3, la machine incorporant une seconde variante du dispositif d'assemblage.Other characteristics and advantages will appear during the following detailed description, given by way of nonlimiting example, with reference to the accompanying drawings, in which: FIG. 1 is a schematic view in longitudinal section of the wall of a sheath with a multi-layer structure according to the invention, FIG. 2 represents a part of the assembly device according to the invention and schematically illustrates the manner in which the sheath with a multi-layer structure according to the invention is assembled, FIG. 3 is a schematic view of a machine for implementing the method of manufacturing a sheath with a multi-layer structure according to the invention, said machine incorporating a first variant of the assembly device, and Figure 4 is a view similar to Figure 3, the machine incorporating a second variant of the assembly device.
En référence à la figure 1 , la gaine 1 selon l'invention comporte une structure multi- couche pouvant par exemple comporter trois couches superposées 10a, 10b, 10c. Bien entendu, le nombre de couches 10 qui est d'au moins deux n'est pas limité et la forme de réalisation de la gaine comportant trois couches telle que représentée sur les figures ne représente qu'un exemple de réalisation avantageux. La structure à trois couches est avantageuse lorsque la gaine est utilisée en tant que gaine de précontrainte car, pour obtenir l'épaisseur de parois minimales requise, c'est-à-dire environ 2 millimètres avant la mise sous tension des câbles, on peut dans ce cas utiliser des couches de matière ayant une épaisseur standard d'environ 0,7 millimètre. Evidemment, si la gaine de câble selon l'invention n'est pas destinée à être utilisée en tant que gaine de précontrainte, l'épaisseur de la paroi peut être inférieure ou supérieure, et le nombre de couches peut par conséquent être différent.With reference to FIG. 1, the sheath 1 according to the invention comprises a multi-layer structure which can for example comprise three superimposed layers 10a, 10b, 10c. Of course, the number of layers 10 which is at least two is not limited and the embodiment of the sheath comprising three layers as shown in the figures only represents an advantageous embodiment. The three-layer structure is advantageous when the sheath is used as a prestressing sheath because, to obtain the minimum wall thickness required, that is to say approximately 2 millimeters before the cables are tensioned, it is possible to in this case use layers of material having a standard thickness of about 0.7 millimeter. Obviously, if the cable sheath according to the invention is not intended to be used as a prestressing sheath, the thickness of the wall may be less or more, and the number of layers may therefore be different.
Selon un aspect de l'invention, la gaine à structure multi-couche comporte au moins une couche en matériau plastique. De préférence, ladite gaine comporte au moins deux couches en matériau plastique superposées, ce qui permet de les lier intimement ensemble comme cela sera expliqué ultérieurement lors de la description du procédé de fabrication de la gaine.According to one aspect of the invention, the sheath with a multi-layer structure comprises at least one layer of plastic material. Preferably, said sheath comprises at least two layers of superimposed plastic material, which makes it possible to bind them intimately together as will be explained later on in the description of the process for manufacturing the sheath.
La description détaillée de l'invention qui sera faite en référence aux dessins concerne plus particulièrement une gaine à structure multi-couche comportant trois couches 10a, 10b, 10c en matière plastique, mais il est clair que la gaine peut comporter une couche réalisée en un autre matériau, tel que de la fibre de verre ou du métal, par exemple.The detailed description of the invention which will be made with reference to the drawings relates more particularly to a sheath with a multi-layer structure comprising three layers 10a, 10b, 10c made of plastic, but it is clear that the sheath may comprise a layer made of a other material, such as fiberglass or metal, for example.
En fait, une caractéristique particulièrement intéressante de la gaine à structure multi-couche de la présente invention réside dans la possibilité de choisir chaque couche dans un matériau particulier ayant des caractéristiques intrinsèques particulières, de sorte que chaque couche de la structure multi-couche remplit une fonction particulière. Par exemple, la couche 10a située à l'intérieur de la gaine peut être réalisée en un matériau qui présente un faible frottement lors de la mise en tension des câbles de précontrainte, par exemple en Teflon ou en polyéthylène haute densité (PEHD) graphité. La seconde couche 10b, c'est-à-dire celle qui est directement superposée sur ladite première couche intérieure 10a, peut elle, par exemple, être réalisée en un matériau présentant une rigidité relativement élevée. La couche extérieure 10c peut être réalisée en un matériau présentant des caractéristiques de bonne résistance aux rayons ultra-violets. Ceci s'avère avantageux notamment lorsque les gaines sont stockées sur un chantier situé dans un pays chaud. Un ramolissement et une déformation de la gaine à cause des rayons solaires peuvent ainsi être limités. Cette structure multi-couche permet également à la gaine de câble selon l'invention d'être adaptée à d'autres utilisations que celle de gaine de précontrainte. Ainsi, une telle gaine peut être utilisée en tant que gaine de hauban. Dans ce cas, les caractéristiques requises pour les couches intérieure 10a et extérieure 10c de la gaine ne sont pas forcément les mêmes que celles d'une gaine de précontrainte, on peut alors choisir des matériaux différents pour les couches constituant ladite gaine. Ainsi, dans une gaine de hauban, la couche extérieure 10c peut par exemple être réalisée en un matériau de couleur pour répondre à des exigences d'esthétique, ledit matériau de couleur présentant également une bonne résistance aux rayons ultra-violets pour garantir une bonne tenue en couleur.In fact, a particularly advantageous characteristic of the sheath with a multi-layer structure of the present invention lies in the possibility of choosing each layer in a particular material having particular intrinsic characteristics, so that each layer of the multi-layer structure fills a special function. For example, the layer 10a located inside the sheath can be made of a material which has a low friction during the tensioning of the prestressing cables, for example Teflon or graphite high density polyethylene (HDPE). The second layer 10b, that is to say the one which is directly superimposed on said first inner layer 10a, can for example be made of a material having a relatively high rigidity. The outer layer 10c can be made of a material having characteristics of good resistance to ultraviolet rays. This is beneficial especially when the sheaths are stored on a site located in a hot country. Softening and deformation of the sheath due to the sun's rays can thus be limited. This multi-layer structure also allows the cable sheath according to the invention to be suitable for other uses than that of prestressing sheath. Thus, such a sheath can be used as a shroud sheath. In this case, the characteristics required for the inner 10a and outer 10c layers of the sheath are not necessarily the same as those of a prestressing sheath, it is then possible to choose different materials for the layers constituting said sheath. Thus, in a shroud sheath, the outer layer 10c can for example be made of a colored material to meet aesthetic requirements, said colored material also having good resistance to ultraviolet rays to guarantee good hold. in colour.
Selon l'invention, chaque couche 10 de la gaine est continue, c'est-à-dire que chaque couche de la gaine forme un manchon fermé 10, la structure multi-couche étant par conséquent une superposition de plusieurs de ces manchons individuels 10a, 10b, 10c. Comme visible sur les figures, chaque couche 10 de la gaine est constituée à partir d'un feuillard ou bande de matière 11 , qui est assemblé de telle manière que ses bords latéraux 12, 13 sont adjacents de manière jointive pour former ledit manchon. Selon une caractéristique de l'invention, lesdits bords latéraux 12a, 13a ; 12b, 13b ; 12c, 13c de chaque feuillard l ia, l lb, 1 le en matière plastique, qui sont adjacents de manière jointive après leur assemblage, sont soudés ensemble thermiquement pour former une couche de gaine en plastique homogène et étanche. De préférence, ces zones de soudure thermique 17 des bords latéraux de chaque feuillard en matière plastique sont décalées d'une couche à l'autre axialement le long de la gaine 1. Ceci assure de manière supplémentaire une étanchéité parfaite de la structure multi-couche de la gaine, ces zones 17 de relative faiblesse d'étanchéité des différentes couches de gaine n'étant pas situées les unes en regard des autres.According to the invention, each layer 10 of the sheath is continuous, that is to say that each layer of the sheath forms a closed sleeve 10, the multi-layer structure therefore being a superposition of several of these individual sleeves 10a , 10b, 10c. As can be seen in the figures, each layer 10 of the sheath is formed from a strip or strip of material 11, which is assembled in such a way that its lateral edges 12, 13 are contiguously adjacent to form said sleeve. According to a characteristic of the invention, said lateral edges 12a, 13a; 12b, 13b; 12c, 13c of each strip l ia, l lb, 1 le of plastic material, which are contiguously adjacent after their assembly, are thermally welded together to form a layer of sheath of homogeneous and waterproof plastic. Preferably, these zones of thermal welding 17 of the lateral edges of each plastic strip are offset from one layer to the other axially along the sheath 1. This additionally ensures perfect sealing of the multi-layer structure of the sheath, these zones 17 of relatively weak sealing of the different layers of sheath not being located opposite one another.
Selon un exemple d'application de l'invention, la gaine 1 comporte sur sa surface extérieure au moins un filet hélicoïdal ou spirale continu 15. Ce filet spirale 15 agit notamment pour remplir l'exigence précitée de transfert des efforts au béton, après durcissement du coulis de ciment. De préférence, ce filet spirale 15 continu extérieur de la gaine est formé par une ou plusieurs nervures longitudinales 14a, 14b, 14c ménagées dans chaque feuillard l ia, l l b, l ie constituant ladite structure multi-couche. Lesdites nervures longitudinales 14a, 14b, 14c des différents feuillards sont de préférence équidistantes de telle manière à se superposer les unes aux autres lors de l'assemblage de ladite gaine. Ainsi, dans l'exemple représenté sur la figure 1, chaque feuillard 1 la, 1 lb, . l ie constituant respectivement les couches 10a, 10b, 10c de la gaine 1 comporte trois nervures longitudinales de forme identique qui se superposent lors de l'assemblage en spirale desdits feuillards, tel que cela sera décrit ultérieurement en référence au procédé. Dans cet exemple de réalisation, la gaine 1 comporte donc sur sa surface extérieure trois filets hélicoïdaux continus 15. Cette caractéristique est particulièrement avantageuse lorsque la gaine a une section transversale circulaire, car elle permet de fixer des raccords de gaine par simple vissage sur lesdits filets spirales 15, aux extrémités de la gaine 1.According to an example of application of the invention, the sheath 1 has on its outer surface at least one continuous helical or spiral thread 15. This spiral thread 15 acts in particular to fulfill the above-mentioned requirement for transfer of forces to concrete, after hardening cement grout. Preferably, this continuous spiral thread 15 outside the sheath is formed by one or more longitudinal ribs 14a, 14b, 14c formed in each strip l ia, llb, the ie constituting said multi-layer structure. Said longitudinal ribs 14a, 14b, 14c of the different strips are preferably equidistant so as to be superposed on each other during the assembly of said sheath. Thus, in the example shown in Figure 1, each strip 1a, 1lb. l ie constituting respectively the layers 10a, 10b, 10c of the sheath 1 comprises three longitudinal ribs of identical shape which are superimposed during the spiral assembly of said strips, as will be described later with reference to the process. In this exemplary embodiment, the sheath 1 therefore has on its outer surface three continuous helical threads 15. This characteristic is particularly advantageous when the sheath has a circular cross section, because it allows the fitting of sheath fittings by simple screwing on said threads. spirals 15, at the ends of the sheath 1.
La largeur des différents feuillards l ia, l lb, l ie formant la structure multi-couche ainsi que le nombre et/ou l'écart entre les nervures longitudinales 14a, 14b, 14c formées dans chacun desdits feuillards l ia, l lb, l ie peuvent être variables, ce qui permet avantageusement de moduler la rigidité de ladite gaine 1.The width of the different strips l ia, l lb, l ie forming the multi-layer structure as well as the number and / or the distance between the longitudinal ribs 14a, 14b, 14c formed in each of said strips l ia, l lb, l ie can be variable, which advantageously makes it possible to modulate the rigidity of said sheath 1.
Selon un autre aspect avantageux de l'invention, un insert 19 est disposé dans la structure multi-couche de la gaine. Cet insert 19, qui peut par exemple être un fil métallique, peut servir à renforcer de manière supplémentaire la rigidité de ladite gaine, mais il peut aussi agir en tant qu'insert chauffant en faisant passer un courant électrique à travers lui. Dans ce cas, ledit insert 19 agit pour chauffer la gaine en cas de température extrêmement basse permettant ainsi d'injecter le coulis de ciment même par temps froid. Cet insert ou fil métallique est avantageusement disposé dans une ou plusieurs desdites nervures longitudinales 14a, 14b, 14c de l'un ou de plusieurs desdits feuillards lia, llb, l ie. Dans ce cas, il s'étend sur toute la longueur de la gaine de manière spiralée.According to another advantageous aspect of the invention, an insert 19 is arranged in the multi-layer structure of the sheath. This insert 19, which may for example be a metal wire, can serve to further strengthen the rigidity of said sheath, but it can also act as a heating insert by passing an electric current through it. In this case, said insert 19 acts to heat the sheath in the event of an extremely low temperature, thus making it possible to inject the cement slurry even in cold weather. This insert or metal wire is advantageously disposed in one or more of said longitudinal ribs 14a, 14b, 14c of one or more of said strips 11a, 11b, 1e. In this case, it extends over the entire length of the sheath in a spiral manner.
Comme mentionné ci-dessus, la gaine selon l'invention peut avoir une section transversale circulaire, mais elle peut aussi avoir une section transversale différente et notamment oblongue, comme visible sur la figure 4. Cette mise en œuvre assure, dans certaines applications, une meilleure répartition des forces de précontrainte, notamment dans les structures minces.As mentioned above, the sheath according to the invention can have a circular cross section, but it can also have a different cross section and in particular oblong, as visible in FIG. 4. This implementation ensures, in certain applications, a better distribution of prestressing forces, especially in thin structures.
L'invention concerne également le procédé de fabrication d'une gaine à structure multi-couche telle que décrite précédemment. Ce procédé comprend essentiellement d'assembler en spirale en les superposant lesdits feuillards au moyen d'un dispositif d'assemblage 20. L'assemblage est réalisé de telle sorte que les bords latéraux respectifs de chaque feuillard soient jointifs pour former des couches de gaines continues. Comme mentionné précédemment, au moins un desdits feuillards l ia, l lb, l ie est en matière plastique et selon un aspect préféré du procédé de fabrication, au moins deux desdits feuillards l ia, l lb, l ie sont en matière plastique pour former au moins deux couches superposées en plastique dans la structure multi-couche de la gaine. Chaque feuillard l ia, l l b, 1 le est alimenté à partir d'un rouleau ou d'une bobineThe invention also relates to the method of manufacturing a sheath with a multi-layer structure as described above. This method essentially comprises assembling in a spiral by superimposing said strips by means of an assembly device 20. The assembly is carried out so that the respective lateral edges of each strip are joined to form continuous sheath layers . As mentioned previously, at least one of said strips l ia, l lb, l ie is made of plastic and according to a preferred aspect of the manufacturing process, at least two of said strips l ia, l lb, l ie are made of plastic to form at least two superimposed layers of plastic in the multi-layer structure of the sheath. Each strip l ia, l l b, 1 le is fed from a roll or a reel
50a, 50b, 50c et pénètre avantageusement d'abord dans un premier module 40 dit de formage de nervures, dans lequel au moins une nervure longitudinale 14a, 14b, 14c est formée respectivement dans ledit feuillard l ia, l lb, 1 le. Ces modules 40 sont adaptés à former des nervures 14a, 14b, 14c identiques dans les différents feuillards constituant la structure multi-couche et comportent avantageusement des moyens de chauffage permettant de déformer la matière pour former lesdites nervures l ia, llb, lie dans chaque feuillard respectif. Lesdits feuillards 1 la, ilb, 1 le constituant la structure multi- couche sont ensuite assemblés, de préférence simultanément comme visible sur les figures 3 et 4, au moyen d'un dispositif d'assemblage 20. Cet assemblage est réalisé de préférence en enroulant en spirale chacun desdits feuillards de telle sorte que leurs nervures longitudinales 1 la, 1 lb, 1 le se superposent. Lesdits feuillards forment ainsi les différentes couches 10a, 10b, 10c de la structure multi-couche de la gaine.50a, 50b, 50c and advantageously first enters a first module 40 called rib forming, in which at least one longitudinal rib 14a, 14b, 14c is respectively formed in said strip l ia, l lb, 1 le. These modules 40 are adapted to form ribs 14a, 14b, 14c which are identical in the different strips constituting the multi-layer structure and advantageously include heating means making it possible to deform the material to form said ribs l ia, llb, linked in each strip respective. Said strips 11a, 11b, 1 constituting the multilayer structure are then assembled, preferably simultaneously as visible in FIGS. 3 and 4, by means of an assembly device 20. This assembly is preferably carried out by winding in spiral each of said strips so that their longitudinal ribs 1a, 1lb, 1 are superimposed. Said strips thus form the different layers 10a, 10b, 10c of the multi-layer structure of the sheath.
Selon une première variante de l'invention, ledit dispositif d'assemblage 20 comporte un mandrin cylindrique fixe 21 qui comporte dans cet exemple au moins un filet hélicoïdal ou spirale continu 22 sur sa surface extérieure. Dans ce cas, le dispositif d'assemblage 20 est adapté à assembler une gaine à structure multi-couche ayant une section transversale sensiblement circulaire. Comme visible sur la figure 2, le mandrin 21 comporte un filet spirale continu 22 pour chaque nervure longitudinale 14a, 14b, 14c des différents feuillard l ia, l lb, Uc. Ainsi dans l'exemple représenté, les feuillards comportent chacun trois nervures longitudinales de même que le mandrin. Ainsi, chacune desdites nervures longitudinales 14a, 14b, 14c de chacun desdits feuillards vient s'engager sur un filet spirale 22 respectif du mandrin 21 , lors de l'assemblage. Cet assemblage se fait avantageusement par enroulement en hélice desdits feuillards autour dudit mandrin 21. Comme visible sur la figure 3, cet enroulement est effectué de préférence au moyen de galets entraîneurs 25 qui sont avantageusement disposés de manière inclinée pour suivre lesdits filets spirales continus 22 du mandrin 21 et qui sont entraînés en rotation par un dispositif 26 approprié. Ces galets 25 agissent notamment pour guider les feuillards de façon à ce que leurs nervures longitudinales 14a, 14b, 14c s'engagent sur lesdits filets spirales 22 du mandrin 21. Chaque feuillard l ia, llb, l ie s'enroule donc autour dudit mandrin 21 pour former une couche 10a, 10b, 10c de la structure multi-couche de la gaine 1 , cet enroulement se faisant de telle manière à ce que les bords latéraux 12a, 13a ; 12b, 13b ; 12c, 13c de chaque feuillard 1 la, llb, lie soient adjacent l'un à l'autre de manière jointive après enroulement autour dudit mandrin 21. Ceci est visible en particulier sur la figure 2 sur laquelle on voit également que l'enroulement des trois feuillards 1 la, l lb, l ie est réalisé de telle sorte que ceux-ci se superposent avec leurs bords latéraux décalés axialement. De préférence, après le formage des nervures longitudinales 14a, 14b, 14c au moyen des modules de formage 40 respectifs, et avant l'enroulement au moyen dudit dispositif d'assemblage 20, le procédé prévoit avantageusement de disposer un module de chauffage 30 pour chaque feuillard en matière plastique, destiné notamment à chauffer ses bords latéraux 12a, 13a ; 12b, 13b ; 12c, 13c. De cette manière, lors de l'enroulement autour du mandrin 21, les bords adjacents chauffés de chaque feuillard en matière plastique sont soudés ensemble thermiquement au moyen desdits galets d'entraînement 25 qui, dans ce cas, agissent également en tant que galets presseurs. Cette caractéristique permet d'obtenir avec chaque feuillard en matière plastique une couche en plastique étanche et homogène.According to a first variant of the invention, said assembly device 20 comprises a fixed cylindrical mandrel 21 which in this example comprises at least one continuous helical or spiral thread 22 on its outer surface. In this case, the assembly device 20 is suitable for assembling a sheath with a multi-layer structure having a substantially circular cross section. As can be seen in FIG. 2, the mandrel 21 comprises a continuous spiral thread 22 for each longitudinal rib 14a, 14b, 14c of the different strips l ia, l lb, Uc. Thus in the example shown, the strips each have three longitudinal ribs as well as the mandrel. Thus, each of said longitudinal ribs 14a, 14b, 14c of each of said strips comes to engage on a respective spiral thread 22 of the mandrel 21, during assembly. This assembly is advantageously done by helically winding said strips around said mandrel 21. As visible in FIG. 3, this winding is preferably carried out by means of driving rollers 25 which are advantageously arranged in an inclined manner to follow said continuous spiral threads 22 of mandrel 21 and which are rotated by a suitable device 26. These rollers 25 act in particular to guide the strips so that their longitudinal ribs 14a, 14b, 14c engage on said spiral threads 22 of the mandrel 21. Each strip l ia, llb, l ie therefore wraps around said mandrel 21 to form a layer 10a, 10b, 10c of the multi-layer structure of the sheath 1, this winding being carried out in such a way that the lateral edges 12a, 13a; 12b, 13b; 12c, 13c of each strip 1a, llb, lie are adjacent to each other in a contiguous manner after winding around said mandrel 21. This is visible in particular in Figure 2 in which we also see that the winding of three strips 1 la, l lb, l ie is produced in such a way that these overlap with their lateral edges offset axially. Preferably, after the forming of the longitudinal ribs 14a, 14b, 14c by means of the forming modules 40 respective, and before winding by means of said assembly device 20, the method advantageously provides for having a heating module 30 for each strip of plastic material, intended in particular to heat its lateral edges 12a, 13a; 12b, 13b; 12c, 13c. In this way, during the winding around the mandrel 21, the adjacent heated edges of each plastic strip are thermally welded together by means of said drive rollers 25 which, in this case, also act as pressure rollers. This characteristic makes it possible to obtain with each plastic strip a tight and homogeneous plastic layer.
De préférence, chacun desdits modules de chauffage 30 est en outre destiné à chauffer localement des zones 18 dites de fusion dans chaque feuillard de sorte que, lors de l'enroulement, lesdites zones chauffées respectives 18 de deux feuillards, qui se superposent lors dudit enroulement, sont pressées l'une contre l'autre au moyen desdits galets presseurs 25, de sorte que lesdites couches superposées formées par lesdits deux feuillards sont liées intimement dans ces zones de fusion 18. On obtient ainsi des liaisons irréversibles entre les différentes couches de la structure multi-couche ce qui garantit une parfaite homogénéité de la gaine 1.Preferably, each of said heating modules 30 is further intended to locally heat so-called melting zones 18 in each strip so that, during winding, said respective heated zones 18 of two strips, which overlap during said winding , are pressed against each other by means of said pressure rollers 25, so that said superimposed layers formed by said two strips are intimately linked in these melting zones 18. This gives irreversible connections between the different layers of the multi-layer structure which guarantees perfect homogeneity of the sheath 1.
Dans certaines applications où la gaine n'est pas noyée dans le béton, les nervures spirales ne servent plus à assurer le transfert des efforts au béton. On peut alors s'en dispenser. On notera cependant que ces nervures paticipent à l'obtention d'une bonne rigidité de la gaine.In certain applications where the sheath is not embedded in the concrete, the spiral ribs no longer serve to ensure the transfer of the forces to the concrete. We can then dispense with it. Note, however, that these ribs participate in obtaining good rigidity of the sheath.
Sur la figure 4 est représentée une seconde variante du dispositif d'assemblage 20 décrit ci-dessus. Dans cette variante, le dispositif d'assemblage 20 ne comporte pas un mandrin fixe, mais deux mandrins cylindriques rotatifs 23a, 23b pouvant chacun comporter un ou plusieurs filets spirales continus (non représentés) sur leur surface extérieure. L'ensemble formé par lesdits deux mandrins rotatifs 23a et 23b est lui-même rotatif autour d'un axe. Ainsi, les feuillards s'enroulent autour desdits deux mandrins 23a, 23b pour former une gaine à structure multi-couche ayant une section transversale oblongue.In Figure 4 is shown a second variant of the assembly device 20 described above. In this variant, the assembly device 20 does not include a fixed mandrel, but two rotary cylindrical mandrels 23a, 23b which may each include one or more continuous spiral threads (not shown) on their outer surface. The assembly formed by said two rotary mandrels 23a and 23b is itself rotary around an axis. Thus, the strips are wound around said two mandrels 23a, 23b to form a sheath with a multi-layer structure having an oblong cross section.
Une fois que les différents feuillards ont été assemblés pour former la gaine à structure multi-couche, celle-ci traverse avantageusement un module de refroidissement 60 pour figer la forme de ladite gaine 1. Etant donné que les modules de chauffage 30 n'agissent que localement c'est-à-dire sur les bords latéraux et dans des zones de fusion particulières de chaque feuillard, ce refroidissement n'est pas indispensable et n'a en tout cas pas besoin d'être particulièrement important. Ensuite, la gaine à structure multi-couche traverse de préférence un module de coupe 70 dans lequel ladite gaine est sectionnée à une longueur quelconque souhaitée. Le procédé de fabrication décrit ci-dessus présente donc des avantages très importants qui sont :Once the various strips have been assembled to form the sheath with a multi-layer structure, the latter advantageously passes through a cooling module 60 in order to freeze the shape of said sheath 1. Since the heating modules 30 only act locally, that is to say on the lateral edges and in particular melting zones of each strip, this cooling is not essential and in any case does not need to be particularly important. Then, the sheath with a multi-layer structure preferably passes through a cutting module 70 in which said sheath is cut to any desired length. The manufacturing process described above therefore has very significant advantages which are:
- la gaine obtenue comporte une structure multi-couche, ce qui implique des avantages mentionnés précédemment, à savoir notamment que selon les caractéristiques souhaitées, le nombre de couches et/ou la matière des feuillards constituant les couches peuvent être modifiés très simplement.- The sheath obtained has a multi-layer structure, which implies the advantages mentioned above, namely in particular that according to the desired characteristics, the number of layers and / or the material of the strips constituting the layers can be modified very simply.
- la machine pour mettre en œuvre ce procédé est simple et peu encombrante et autorise donc une fabrication sur site, c'est-à-dire sur chantier, de la gaine à structure multi- couche de l'invention. - la gaine obtenue avec ce procédé peut comporter un ou plusieurs filets spirales continus sur sa surface extérieure ce qui permet d'effectuer des raccords de gaine par simple vissage de manchons appropriés, quelque soit la longueur souhaitée de la gaine.- The machine for implementing this process is simple and space-saving and therefore allows manufacturing on site, that is to say on site, of the sheath with a multilayer structure of the invention. - The sheath obtained with this process may include one or more continuous spiral threads on its outer surface which allows sheath connections to be made by simply screwing in suitable sleeves, whatever the desired length of the sheath.
- le module de coupe permet de couper la gaine obtenue à une longueur quelconque souhaitée. Le fait que ce procédé peut être mis en œuvre sur chantier permet éventuellement de réaliser des gaines de grandes longueurs ce qui est impossible lorsque les gaines doivent être transportées de l'usine au chantier.- the cutting module makes it possible to cut the sheath obtained to any desired length. The fact that this process can be implemented on site possibly makes it possible to produce ducts of great length, which is impossible when the ducts have to be transported from the factory to the site.
- les coûts énergétiques dudit procédé sont faibles en raison du chauffage en des points localisés uniquement.- The energy costs of said process are low due to the heating at localized points only.
- en remplaçant simplement le mandrin fixe de la première variante du dispositif d'assemblage par un mandrin ayant un diamètre extérieur légèrement supérieur, la machine pour mettre en œuvre le procédé de fabrication de la gaine selon l'invention permet aussi de réaliser sur site lesdits manchons de raccord qui se vissent sur les extrémités desdites gaines pour raccorder celles-ci. - by simply replacing the fixed mandrel of the first variant of the assembly device by a mandrel having a slightly larger outside diameter, the machine for implementing the process for manufacturing the sheath according to the invention also makes it possible to carry out said sites on site. connection sleeves which are screwed onto the ends of said sheaths to connect the latter.

Claims

Revendications : Claims:
1.- Gaine de câble (1) de précontrainte, caractérisée en ce qu'elle comporte une structure multi-couche comportant au moins deux couches continues superposées (10a,1.- Cable sheath (1) of prestressing, characterized in that it comprises a multi-layer structure comprising at least two continuous superposed layers (10a,
10b) en matériau plastique, constituée chacune d'un feuillard (l ia, 1 lb) disposé en hélice et dont les bords latéraux (12a, 13a ; 12b, 13b) sont respectivement jointifs avec jonctions étanches.10b) of plastic material, each consisting of a strip (l ia, 1 lb) arranged in a helix and whose lateral edges (12a, 13a; 12b, 13b) are respectively contiguous with tight junctions.
2.- Gaine de câble selon la revendication 1 , dans laquelle lesdites au moins deux couches (10a, 10b) en matière plastique sont soudées l'une à l'autre en au moins un point (18).2.- cable sheath according to claim 1, wherein said at least two layers (10a, 10b) of plastic are welded to each other at at least one point (18).
3.- Gaine de câble selon la revendication 1 ou 2, comportant sur sa surface extérieure au moins un filet hélicoïdal continu (15).3.- Cable sheath according to claim 1 or 2, comprising on its outer surface at least one continuous helical thread (15).
4.- Gaine de câble selon l'une quelconque des revendications précédentes, dans laquelle un insert (19), tel qu'un fil métallique, est disposé dans la structure multi-couche de la gaine, notamment dans au moins un filet hélicoïdal (15).4. Cable sheath according to any one of the preceding claims, in which an insert (19), such as a metal wire, is arranged in the multi-layer structure of the sheath, in particular in at least one helical thread ( 15).
5.- Procédé de fabrication d'une gaine de câble, caractérisé en ce qu'il comprend les étapes suivantes : fournir au moins deux feuillards (l ia, 11 b) en matière plastique, assembler en hélice, en les superposant au moyen d'un dispositif d'assemblage (20), chacun desdits feuillards (1 1 ), de telle sorte que ses bords latéraux respectifs (12, 13) soient jointifs pour former une gaine (1) à structure multi- couche comportant au moins deux couches en plastique.5.- A method of manufacturing a cable sheath, characterized in that it comprises the following steps: supply at least two strips (l ia, 11 b) of plastic material, assemble in a helix, superimposing them by means of 'An assembly device (20), each of said strips (1 1), so that their respective lateral edges (12, 13) are joined to form a sheath (1) with a multilayer structure comprising at least two layers in plastic.
6.- Procédé selon la revendication 5, dans lequel l'étape d'assembler comporte en outre de souder en au moins un point ( 18) lesdites au moins deux couches superposées en plastique de la gaine.6. The method of claim 5, wherein the step of assembling further comprises welding at least one point (18) said at least two superimposed plastic layers of the sheath.
7.- Procédé selon la revendication 6, comportant, avant l'assemblage, l'étape de chauffer localement des zones de fusion (18) des feuillards en matière plastique, l'étape d'assembler comportant en outre de presser les zones de fusion chauffées (18) respectives des feuillards en matière plastique qui se superposent lors de l'assemblage, de sorte que lesdites couches superposées en plastique de la gaine sont soudées dans ces zones de fusion. 7. A method according to claim 6, comprising, before assembly, the step of locally heating melting zones (18) of plastic strips, the assembling step further comprising pressing the melting zones. heated (18) respective plastic strips which overlap during assembly, so that said superimposed plastic layers of the sheath are welded in these melting zones.
8.- Procédé selon l'une quelconque des revendications 5 à 7, comportant, avant l'assemblage, l'étape de chauffer les bords latéraux (12, 13) de chaque feuillard (11) en matière plastique, l'étape d'assembler comportant en outre de presser lesdits bords latéraux chauffés de chaque feuillard en matière plastique lorsqu'ils sont adjacents, pour les souder ensemble thermiquement ( 17) pour former une couche de gaine en plastique homogène et étanche.8.- Method according to any one of claims 5 to 7, comprising, before assembly, the step of heating the lateral edges (12, 13) of each strip (11) of plastic, the step of assembly comprising further pressing said heated side edges of each plastic strip when they are adjacent, to weld them together thermally (17) to form a layer of sheath of homogeneous and waterproof plastic.
9.- Procédé selon l'une quelconque des revendications 5 à 8, comportant, avant l'assemblage, l'étape de former au moins une nervure longitudinale (14) dans chaque feuillard (11), et l'étape d'assembler comprend d'enrouler en hélice les feuillards (11) de telle sorte que les au moins une nervures longitudinales (14) de chaque feuillard (11) respectif se superposent pour former au moins un filet hélicoïdal continu (15) sur la surface extérieure de la gaine ( 1).9.- Method according to any one of claims 5 to 8, comprising, before assembly, the step of forming at least one longitudinal rib (14) in each strip (11), and the step of assembling comprises wind helically the strips (11) so that the at least one longitudinal ribs (14) of each respective strip (11) overlap to form at least one continuous helical thread (15) on the outer surface of the sheath (1).
10.- Machine pour mettre en œuvre le procédé selon l'une quelconque des revendications 5 à 9, caractérisée en ce qu'elle comprend au moins deux bobines (50) pour recevoir des rouleaux de feuillard pour fournir lesdits au moins deux feuillards (1 la, l lb), et un dispositif d'assemblage (20) pour assembler les feuillards en hélice de telle sorte que leurs bords latéraux respectifs (12a, 13a ; 12b, 13b) soient jointifs.10.- Machine for implementing the method according to any one of claims 5 to 9, characterized in that it comprises at least two reels (50) for receiving strip rolls to supply said at least two strips (1 la, l lb), and an assembly device (20) for assembling the helical strips so that their respective lateral edges (12a, 13a; 12b, 13b) are contiguous.
I L- Machine selon la revendication 10, dans laquelle le dispositif d'assemblage (20) comporte un mandrin cylindrique fixe (21) autour duquel viennent s'enrouler en hélice les feuillards (11).I L- Machine according to claim 10, wherein the assembly device (20) comprises a fixed cylindrical mandrel (21) around which are wound helically the strips (11).
12.- Machine selon la revendication 11, dans laquelle le dispositif d'assemblage (20) comporte deux mandrins cylindriques rotatifs (23a, 23b) autour desquels viennent s'enrouler en hélice les feuillards (11), l'ensemble formé par lesdits deux mandrins rotatifs (23a, 23b) étant lui-même rotatif.12.- Machine according to claim 11, wherein the assembly device (20) comprises two rotary cylindrical mandrels (23a, 23b) around which come to wind helically the strips (11), the assembly formed by said two rotary mandrels (23a, 23b) being itself rotary.
13.- Machine selon la revendication 11, comportant en outre un module de formage de nervure (40) pour chaque feuillard, destiné à former au moins une nervure longitudinale (14) dans chaque feuillard (11), avant son assemblage, ledit mandrin cylindrique fixe (21) comportant au moins un filet hélicoïdal continu (22) sur sa surface extérieure, sur lequel vient s'enrouler une nervure longitudinale (14) respective de chaque feuillard (11). 13.- Machine according to claim 11, further comprising a rib forming module (40) for each strip, intended to form at least one longitudinal rib (14) in each strip (11), before its assembly, said cylindrical mandrel fixed (21) comprising at least one continuous helical thread (22) on its outer surface, on which is wound a longitudinal rib (14) respective of each strip (11).
EP96922920A 1995-06-19 1996-06-13 Multilayer cable sheath, method for making same and machine therefor Withdrawn EP0833994A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9507290 1995-06-19
FR9507290A FR2735511B1 (en) 1995-06-19 1995-06-19 MULTI-LAYERED CABLE SHEATH, MANUFACTURING METHOD THEREOF, AND MACHINE FOR CARRYING OUT SAID METHOD
PCT/FR1996/000905 WO1997000361A1 (en) 1995-06-19 1996-06-13 Multilayer cable sheath, method for making same and machine therefor

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EP0833994A1 true EP0833994A1 (en) 1998-04-08

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EP (1) EP0833994A1 (en)
JP (1) JPH11508005A (en)
AU (1) AU709765B2 (en)
CA (1) CA2225166A1 (en)
FR (1) FR2735511B1 (en)
NO (1) NO975904L (en)
WO (1) WO1997000361A1 (en)

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FR2781829B1 (en) 1998-07-29 2000-10-13 Freyssinet Int Stup IMPROVED CABLE SHEATH
CN1366570A (en) * 2000-04-20 2002-08-28 钢弦器材株式会社 Sheath pipe, sheath pipe manufacturing method, and sheath pipe manufacturing apparatus
US6705351B2 (en) * 2002-03-26 2004-03-16 Wellstream International Limited Flexible pipe and method of fabricating same using overlapping layers
EP2657407B1 (en) * 2010-12-21 2015-10-28 Solana Techno Corporation Wrapping wire with c-shaped cross-section, and cable wrapping structure and method using the same
CN103924515A (en) * 2014-04-11 2014-07-16 浙江省交通规划设计研究院 Protecting steel wire for main cable of suspension bridge
CN107090771A (en) * 2017-04-19 2017-08-25 柳州市邱姆预应力机械有限公司 Separate type hot-cast anchor rope and preparation method

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FR1222347A (en) * 1958-04-28 1960-06-09 Stup Procedes Freyssinet Machine for manufacturing sheaths for cables or bars and sheaths manufactured by this device
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JPH11508005A (en) 1999-07-13
FR2735511B1 (en) 1997-08-29
CA2225166A1 (en) 1997-01-03
NO975904D0 (en) 1997-12-16
AU6361796A (en) 1997-01-15
AU709765B2 (en) 1999-09-09
NO975904L (en) 1998-02-18
WO1997000361A1 (en) 1997-01-03
FR2735511A1 (en) 1996-12-20

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