EP0058112A2 - Sheathing for assuring the centering of a cable core in its covering, a cable containing such a device, and the method of its manufacture - Google Patents

Sheathing for assuring the centering of a cable core in its covering, a cable containing such a device, and the method of its manufacture Download PDF

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Publication number
EP0058112A2
EP0058112A2 EP82400168A EP82400168A EP0058112A2 EP 0058112 A2 EP0058112 A2 EP 0058112A2 EP 82400168 A EP82400168 A EP 82400168A EP 82400168 A EP82400168 A EP 82400168A EP 0058112 A2 EP0058112 A2 EP 0058112A2
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EP
European Patent Office
Prior art keywords
cable
core
fin
envelope
coating
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.)
Granted
Application number
EP82400168A
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German (de)
French (fr)
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EP0058112A3 (en
EP0058112B1 (en
Inventor
Jean-Pierre Hulin
Jean-Claude Staath
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Lignes Telegraphiques et Telephoniques LTT SA
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Lignes Telegraphiques et Telephoniques LTT SA
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Publication of EP0058112A2 publication Critical patent/EP0058112A2/en
Publication of EP0058112A3 publication Critical patent/EP0058112A3/en
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Publication of EP0058112B1 publication Critical patent/EP0058112B1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/06—Insulating conductors or cables
    • H01B13/10—Insulating conductors or cables by longitudinal lapping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
    • H01B7/18—Protection against damage caused by wear, mechanical force or pressure; Sheaths; Armouring

Definitions

  • the present invention relates to a coating intended to ensure the centering of a cable core in its envelope, a cable comprising such a device and its manufacturing process.
  • the present invention thus relates to a coating which ensures the centering of a cable core in its envelope and which at the same time ensures mechanical decoupling between the cable core and its envelope.
  • the coating according to the invention consists of a sheath provided with at least one elastic fin, so that the mechanical stresses are supported by the envelope and the sheath without being retransmitted to the actual core of the cable.
  • the invention also relates to a method of manufacturing such a coating in which the edges of at least one are brought into coincidence.
  • ribbon over a predetermined width, around the core of a cable and. where said edges are joined together on at least part of said width so as to produce at least one elastic fin.
  • FIG. 1 represents a cable described in the aforementioned French patent 1,593,816. It comprises a core 1 coated with ribbons 2 made of plastic material and of a sheath 3 also made of plastic material provided with fins 4 which are longitudinal or not very long, called to delimit empty spaces 6 between the sheath 3 and its metallic envelope.
  • the metal casing 5 is tightened fairly tightly on the bearing ends of the fins 4 so as to prevent the cable from slipping inside its casing.
  • this rigid anchoring does not provide satisfactory centering, because it transmits to the core of the cable all the stresses to which the envelope is subjected during the unwinding and winding of the cable or when the cable is in operation.
  • FIG. 2 represents a cable according to the invention, the core 7 of which is surrounded by a covering 8 provided with elastic fins 10 and an envelope 12, possibly wavy. Spaces 11 remain between the covering 8 and the casing 12 and the fins 10 have a height p at least equal to the dimension of the spaces 11 in a radial direction, hereinafter referred to as depth, which corresponds to the play existing between the core of the cable and its envelope.
  • the centering of the core relative to the envelope loppe is not a centering imposed by a mechanical blocking, but a self-centering which is achieved by the elastic recovery of the fins 10 when they are moved from a state of equilibrium.
  • the self-centering of the core thereof makes it possible to avoid constraints due to the winding or unwinding lengths which would be different for an off-center core and envelope .
  • the connection between the core and its envelope is achieved simply by the friction forces between the fins and the internal face of the envelope, the mechanical and / or thermal stresses to which the envelope is susceptible to be submitted to the operating site will result in a relative translation of the envelope and the core without, however, this being subject to constraints. Indeed, the only forces present in practice are those corresponding to the friction of the core with respect to the envelope or to an ovalization of the envelope, and the stresses which result therefrom are almost entirely absorbed by the fin (s).
  • a polypropylene covering 0.2 mm thick and fins 0.4 mm in diameter have been used. thickness and 1 mm in height, this height being at least equal to the depth of the spaces 11.
  • the respective thicknesses of a coating of high density polyethylene and fins are, for example, 0.1 mm and 0.2 mm and on the other hand the height of the fins is 0.4 mm.
  • the play existing between the core of the cable and its envelope is generally determined by the maximum ovalization to which the envelope is likely to be subjected during the use of the cable or by the necessary average play between the core of the cable and its envelope, which makes it possible to determine the minimum height of the fins.
  • the specifications of the cable in question make it possible to determine ner the maximum eccentricity tolerated for the cable core with respect to its envelope.
  • any eccentricity results, during the winding and unwinding operations, by a different length due to the fact that the winding radii are not entirely identical, which generates stresses at the core of the cable.
  • the setting of a maximum offset value makes it possible to correlatively limit the stresses undergone by the cable core. This is important in the case of optical fiber cables, the optical fibers being able to withstand only low stresses. Otherwise, their performance will deteriorate.
  • the definition of the maximum tolerated eccentricity then makes it possible to choose the nature of the material of the fins according to its modulus of elasticity E as well as the thickness of the fins so that the weight of the core produces at rest only one offset less than the maximum tolerated offset.
  • the frictional forces between the covering fin (s) and the cable envelope are sufficient to prevent relative sliding of the core and the envelope when the cable is vertical, and / or presence of vibrations when the cable is laid.
  • the height of the fin (s) will be chosen greater than the clearance existing between the core of the cable and its casing so that the 10 "fin or fins (FIG. 4 b ) have an initial deformation, with or without prestressing when the casing is laid, thus creating in the first case a prestressing force increasing the friction (the folding of the fins has been exaggerated in FIG. 4 b).
  • fins of section other than rectangular in order to obtain a structure of equal resistance, for example by extrusion. It is thus possible to use fins with a truncated parabolic profile or else with a trapezoidal profile. The calculation is then done according to the same laws.
  • FIG. 3 illustrates a method of manufacturing a coating according to the invention, in which ribbons 18 disposed on coils 14, here 4 in number, distributed around the core 7 to be coated, are brought into coincidence on their edges, over a width corresponding to the desired height for the fins, their edges then being welded at this level.
  • the core is animated by an axial translational movement along arrow F and the ribbons 18 see their edges brought into contact at 21 as they unfold, at the level of grooves 20 formed on the face internal of a guide cylinder 19, the axis of which is the axis of movement of the core 7.
  • heads or pairs of welding heads are arranged which weld the portions of ribbon brought into contact by the grooves 20.
  • the cylinder 19 is replaced by pairs of rollers with axes parallel to the axis of movement of the core 7 of the cable, and which are spaced so as to pinch two thicknesses of ribbons 18.
  • pairs of rollers will be used per groove 10 and the tape portions will be welded between the two pairs of rollers.
  • a covering 8 made from ribbons welded at their edges will have the shape shown in FIG. 2, that is to say that the edges of the ribbon 18 are integral on a thinner part corresponding to approximately two thicknesses of the ribbon up to 'to a projecting portion forming a thicker portion 9 which has a diameter slightly greater than the average diameter of the coating 8.
  • a covering 8 provided with elastic fins 10 can be produced by extrusion in a extruder through a head whose profile corresponds to that of the covering 8.
  • a covering 8 produced by extrusion has been shown in partial section and comprising fins 10 'profiled from a wide portion 22, which connect them to the cylindrical contour of the coating, to a narrow portion 23 at their ends, for example according to a truncated or trapezoidal parabolic profile.
  • the fins 10 can be longitudinal. They can also be helical or with alternating pitch: in the case of manufacture from strips, all of the coils 14 and the guide cylinder 19, or the pairs of rollers, will be given a corresponding movement around the axis of movement of the core 7; or else the core 7 will be rotated about its axis of movement, for example by rotating a coil which receives it and / or a reel which delivers it, around an axis perpendicular to its longitudinal axis. In the case of manufacture by extrusion, the extrusion apparatus will be rotated or else, as mentioned above, the core of the cable.
  • the centering of the cable in its envelope can be carried out using an envelope provided with a single fin, preferably helical or with alternating pitch.
  • a propeller or an alternating pitch will have a fairly short pitch, for example of the order of magnitude of the coating diameter, so that the eccentricity of the cable core, which will be compensated at worst half a step further by the elastic recovery of the fin, is corrected effectively.
  • the space or clearance existing between the cylindrical part of the covering 8 and the casing 12 is greater than the space or the clearance which is tolerated between the core of a cable and its outer casing in the cable technique in general, and in particular in the case of a cable as described in French patent 1,593,816. This greater play is used for the self-centering that the coating according to the invention allows.
  • the depth of the fin or fins is periodically variable between a maximum value and a minimum value, this variation being out of phase in the case of several fins.
  • the drums 14 are mounted on an eccentric, the eccentricity of which corresponds to the amplitude of variation of the depth of the fins and the speed of rotation of which will define the pitch of the variation, in relation to the speed of travel of the cable core.
  • a extruder will be used provided with a variable extrusion profile at the level of the fins, the variation being controlled for example by an eccentric.
  • the variation in depth of the fins will make it possible to have an extra length of the core of the cable inside the envelope, the core of the cable coated with its fin sheath being positioned in a helix due to the periodic variation of the depth. fins, and therefore around an average position corresponding to centering.
  • the pull on the envelope will produce a slight elongation thereof (for example of the order of 0.5%), so that after unwinding, the lengths of the cable and core will be equal.
  • the core of the cable will no longer necessarily be centered, which is only of little importance for a laid cable. Indeed, only mechanical (ovalization of the envelope) and / or thermal stresses will be undergone by the cable, and for these the precise centering of the core is not important.
  • the invention is not limited to the embodiments described. above. Thus, it is not necessary that the fins are made of the same material as the cylindrical part of the coating 8. On the other hand, the fins, whether or not made of the same material as the coating 8 in its cylindrical part, can be reinforced with one or more elastic tapes.

Abstract

1. A covering for ensuring the centering of a cable (7) core in its sheath (12) and comprising at least one elastic fin (10), characterized in that the fin (10) is of periodically variable height.

Description

La présente invention a pour objet un revêtement destiné à assurer le centrage d'une âme de câble dans son enveloppe, un câble comportant un tel dispositif et son procédé de fabrication.The present invention relates to a coating intended to ensure the centering of a cable core in its envelope, a cable comprising such a device and its manufacturing process.

On sait déjà du brevet français 1 593 816 déposé par la Demanderesse que l'on peut disposer à l'intérieur d'une enveloppe métallique, notamment ondulée, une gaine rainurée réalisée par extrusion et qui sert à la fois d'écran thermique et de verrouillage entre gaine et enveloppe. Toutefois, étant donné que le verrouillage est obtenu par écrasement par l'enveloppe des ailettes de la gaine rainurée, le centrage par verrouillage n'est pas en pratique très satisfaisant notamment du fait qu'il retransmet à l'âme du câble toutes les contraintes auxquelles son enveloppe est soumise. Ceci représente un inconvénient assez gênant, notamment dans le cas des câbles à fibres optiques.It is already known from French patent 1,593,816 filed by the Applicant that it is possible to have inside a metallic envelope, in particular corrugated, a grooved sheath produced by extrusion and which serves both as a heat shield and to locking between sheath and enclosure. However, since the locking is obtained by crushing by the envelope of the fins of the grooved sheath, the centering by locking is not in practice very satisfactory in particular because it retransmits all the stresses to the core of the cable to which its envelope is subjected. This represents a rather annoying drawback, in particular in the case of optical fiber cables.

La présente invention a ainsi pour objet un revêtement qui assure le centrage d'une âme de câble dans son enveloppe et qui assure en même temps un découplage mécanique entre l'âme du câble et son enveloppe.The present invention thus relates to a coating which ensures the centering of a cable core in its envelope and which at the same time ensures mechanical decoupling between the cable core and its envelope.

Le revêtement selon l'invention est constitué par une gaine pourvue d'au moins une ailette élastique, de telle sorte que les contraintes mécaniques soient supportées par l'enveloppe et la gaine sans être retransmises à l'âme proprement dite du câble.The coating according to the invention consists of a sheath provided with at least one elastic fin, so that the mechanical stresses are supported by the envelope and the sheath without being retransmitted to the actual core of the cable.

L'invention concerne également un procédé de fabrication d'un tel revêtement où on amène en coïncidence les bords d'au moins un . ruban sur une largeur prédéterminée, autour de l'âme d'un câble et . où on solidarise entre eux lesdits bords sur au moins une partie de ladite largeur de manière à réaliser au moins une ailette élastique.The invention also relates to a method of manufacturing such a coating in which the edges of at least one are brought into coincidence. ribbon over a predetermined width, around the core of a cable and. where said edges are joined together on at least part of said width so as to produce at least one elastic fin.

L'invention sera mieux comprise à la lecture de la description ci-dessous donnée à titre d'exemple non limitatif et en se référant aux dessins ci-ann-exés où :

  • - la figure 1 représente en coupe une gaine de l'art antérieur,
  • - la figure 2 représente en coupe un revêtement suivant l'invention,
  • - la figure 3 représente un dispositif destiné à la fabrication d'un revêtement selon un mode de réalisation de l'invention,
  • - la figure 4a représente en coupe un détail d'un revêtement extrudé selon l'invention,
  • - la figure 4b représente une variante d'une ailette suivant l'invention.
The invention will be better understood on reading the description below given by way of nonlimiting example and with reference to the drawings below, where:
  • FIG. 1 represents in section a sheath of the prior art,
  • FIG. 2 represents in section a coating according to the invention,
  • FIG. 3 represents a device intended for the manufacture of a coating according to an embodiment of the invention,
  • FIG. 4a represents in section a detail of an extruded coating according to the invention,
  • - Figure 4b shows a variant of a fin according to the invention.

La figure 1 représente un câble décrit dans le brevet français 1 593 816 précité. Il comporte une âme 1 revêtue de rubans 2 en matière plastique et d'une gaine 3 également en matière plastique munie d'ailettes 4 longitudinales ou à pas très long, appelées à délimiter des espaces vides 6 entre la gaine 3 et son enveloppe métallique .FIG. 1 represents a cable described in the aforementioned French patent 1,593,816. It comprises a core 1 coated with ribbons 2 made of plastic material and of a sheath 3 also made of plastic material provided with fins 4 which are longitudinal or not very long, called to delimit empty spaces 6 between the sheath 3 and its metallic envelope.

L'enveloppe métallique 5 est serrée assez fortement sur les extrémités portantes des ailettes 4 de manière à éviter le glissement du câble à l'intérieur de son enveloppe. Ainsi qu'il a été dit plus haut, cet ancrage rigide n'assure pas un centrage satisfaisant, car il retransmet à l'âme du câble toutes les contraintes auxquelles l'enveloppe est soumise lors du déroulage et de l'enroulage du câble ou lorsque le câble est en exploitation.The metal casing 5 is tightened fairly tightly on the bearing ends of the fins 4 so as to prevent the cable from slipping inside its casing. As was said above, this rigid anchoring does not provide satisfactory centering, because it transmits to the core of the cable all the stresses to which the envelope is subjected during the unwinding and winding of the cable or when the cable is in operation.

La figure 2 représente un câble selon l'invention dont l'âme 7 est entourée d'un revêtement 8 pourvu d'ailettes 10 élastiques et d'une enveloppe 12 éventuellement ondulée. Des espaces 11 subsistent entre le revêtement 8 et l'enveloppe 12 et les ailettes 10 ont une hauteur p au moins égale à la dimension des espaces 11 dans une direction radiale, dénommée ci-dessous profondeur, laquelle correspond au jeu existant entre l'âme du câble et son enveloppe.FIG. 2 represents a cable according to the invention, the core 7 of which is surrounded by a covering 8 provided with elastic fins 10 and an envelope 12, possibly wavy. Spaces 11 remain between the covering 8 and the casing 12 and the fins 10 have a height p at least equal to the dimension of the spaces 11 in a radial direction, hereinafter referred to as depth, which corresponds to the play existing between the core of the cable and its envelope.

Selon l'invention, le centrage de l'âme par rapport à l'enveloppe est non pas un centrage imposé par un blocage mécanique, mais un auto-centrage qui est réalisé grâce à la reprise élastique des ailettes 10 lorsqu'elles sont écartées d'un état d'équilibre. Lorsqu'on enroule ou lorsqu'on déroule le câble, l'auto-centrage de l'âme de celui-ci permet d'éviter des contraintes dues aux longueurs d'enroulement ou de déroulement qui seraient différentes pour une âme et une enveloppe décentrées. D'autre part, étant donné que la liaison entre l'âme et son enveloppe est réalisée simplement par les forces de frottement entre les ailettes et la face interne de l'enveloppe, les contraintes mécaniques et/ou thermiques auxquelles l'enveloppe est susceptible d'être soumise sur le site d'exploitation se traduiront par une translation relative de l'enveloppe et de l'âme sans que toutefois celle-ci soit soumise à des contraintes. En effet, les seules forces présentes en pratique sont celles correspondant au frottement de l'âme par rapport à l'enveloppe ou à une ovalisation de l'enveloppe, et les contraintes qui en résultent sont presque entièrement absorbées par la ou les ailettes.According to the invention, the centering of the core relative to the envelope loppe is not a centering imposed by a mechanical blocking, but a self-centering which is achieved by the elastic recovery of the fins 10 when they are moved from a state of equilibrium. When the cable is wound or unwound, the self-centering of the core thereof makes it possible to avoid constraints due to the winding or unwinding lengths which would be different for an off-center core and envelope . On the other hand, since the connection between the core and its envelope is achieved simply by the friction forces between the fins and the internal face of the envelope, the mechanical and / or thermal stresses to which the envelope is susceptible to be submitted to the operating site will result in a relative translation of the envelope and the core without, however, this being subject to constraints. Indeed, the only forces present in practice are those corresponding to the friction of the core with respect to the envelope or to an ovalization of the envelope, and the stresses which result therefrom are almost entirely absorbed by the fin (s).

A titre d'exemple, pour un câble de télécommunication dont l'enveloppe a un diamètre extérieur de 15 mm, on a mis en oeuvre un revêtement en polypropylène de 0,2 mm d'épaisseur et des ailettes de 0,4 mm d'épaisseur et de 1 mm de hauteur, cette hauteur étant au moins égale à la profondeur des espaces 11. Pour un câble à fibres optiques de 4 mm de diamètre entouré d'une enveloppe métallique, les épaisseurs respectives d'un revêtement en polyéthylène haute densité et des ailettes sont, à titre d'exemple, de 0,1 mm et 0,2 mm et d'autre part la hauteur des ailettes est de 0,4 mm.By way of example, for a telecommunication cable whose envelope has an outside diameter of 15 mm, a polypropylene covering 0.2 mm thick and fins 0.4 mm in diameter have been used. thickness and 1 mm in height, this height being at least equal to the depth of the spaces 11. For a fiber optic cable of 4 mm in diameter surrounded by a metallic envelope, the respective thicknesses of a coating of high density polyethylene and fins are, for example, 0.1 mm and 0.2 mm and on the other hand the height of the fins is 0.4 mm.

1 Pour déterminer les ailettes, on prendra en compte un certain nombre de paramètres. 1 To determine the fins, a number of parameters will be taken into account.

Le jeu existant entre l'âme du câble et son enveloppe est en général déterminé par l'ovalisation maximale à laquelle l'enveloppe sera susceptible d'être soumise lors de l'utilisation du câble ou par le jeu moyen nécessaire entre l'âme du câble et son enveloppe, ce qui permet de déterminer la hauteur minimale des ailettes.The play existing between the core of the cable and its envelope is generally determined by the maximum ovalization to which the envelope is likely to be subjected during the use of the cable or by the necessary average play between the core of the cable and its envelope, which makes it possible to determine the minimum height of the fins.

Le cahier des charges du câble considéré permet de déterminer l'excentrement maximal toléré pour l'âme du câble par rapport à son enveloppe. Ainsi qu'il a été dit plus haut, tout excentrement se traduit, lors des opérations d'enroulage et de déroulage, par une longueur différente due au fait que les rayons d'enroulement ne sont pas tout à fait identiques, ce qui engendre des contraintes au niveau de l'âme du câble. La fixation d'une valeur maximale d'excentrement permet de limiter corrélativement les contraintes subies par l'âme du câble. Ceci est important dans le cas des câbles à fibres optiques, les fibres optiques ne pouvant supporter que des contraintes peu élevées. Dans le cas contraire, en effet, leurs performances se détériorent.The specifications of the cable in question make it possible to determine ner the maximum eccentricity tolerated for the cable core with respect to its envelope. As mentioned above, any eccentricity results, during the winding and unwinding operations, by a different length due to the fact that the winding radii are not entirely identical, which generates stresses at the core of the cable. The setting of a maximum offset value makes it possible to correlatively limit the stresses undergone by the cable core. This is important in the case of optical fiber cables, the optical fibers being able to withstand only low stresses. Otherwise, their performance will deteriorate.

La définition de l'excentrement maximal toléré permet alors de choisir la nature du matériau des ailettes selon son module d'élasticité E de même que l'épaisseur des ailettes de telle sorte que le poids de l'âme ne produise au repos qu'un excentrement inférieur à l'excentrement maximal toléré.The definition of the maximum tolerated eccentricity then makes it possible to choose the nature of the material of the fins according to its modulus of elasticity E as well as the thickness of the fins so that the weight of the core produces at rest only one offset less than the maximum tolerated offset.

En effet, les lois connues de la mécanique permettent de déterminer la géométrie à donner aux ailettes en fonction de la masse linéique du câble et du jeu moyen entre l'âme du câble et son enveloppe. L'effort de compression que subira l'ailette devra être en tout point inférieur à la charge critique d'Euler Pc de manière à éviter le flambage. On se limitera en pratique à une charge au repos inférieure à 0,7 fois la charge critique d'Euler. La méthode de Dutheil permet de calculer la déformation résultante. La déformation maximale lorsque le câble est au repos en position horizontale devra correspondre à un excentrement inférieur à l'excentrement maximal toléré.Indeed, the known laws of mechanics make it possible to determine the geometry to be given to the fins as a function of the linear mass of the cable and of the average clearance between the core of the cable and its envelope. The compression force that the fin will undergo must be at all points below the critical load of Euler Pc so as to avoid buckling. In practice, we will limit ourselves to a load at rest less than 0.7 times the critical load of Euler. The Dutheil method makes it possible to calculate the resulting deformation. The maximum deformation when the cable is at rest in the horizontal position must correspond to an eccentricity less than the maximum tolerated eccentricity.

Enfin, il est également préférable que les forces de frottement entre la ou les ailettes du revêtement et l'enveloppe du câble soient suffisantes pour empêcher un glissement relatif de l'âme et de l'enveloppe lorsque le câble est vertical, et/ou en présence de vibrations lorsque le câble est posé.Finally, it is also preferable that the frictional forces between the covering fin (s) and the cable envelope are sufficient to prevent relative sliding of the core and the envelope when the cable is vertical, and / or presence of vibrations when the cable is laid.

Selon un mode de réalisation avantageux, la hauteur de la ou des ailettes sera choisie supérieure au jeu existant entre l'âme du câble et son enveloppe de telle sorte que la ou les ailettes 10" (figure 4b) présentent une déformation initiale, avec ou sans précontrainte lors de la pose de l'enveloppe, créant ainsi dans le premier cas une force de précontrainte augmentant les frottements (le repliement des ailettes a été exagéré à la figure 4 b).According to an advantageous embodiment, the height of the fin (s) will be chosen greater than the clearance existing between the core of the cable and its casing so that the 10 "fin or fins (FIG. 4 b ) have an initial deformation, with or without prestressing when the casing is laid, thus creating in the first case a prestressing force increasing the friction (the folding of the fins has been exaggerated in FIG. 4 b).

La déformation et le moment fléchissant des ailettes sont alors également donnés par des relations connues et on veillera dans ce cas également à rester assez nettement en deçà de la charge critique d'Euler.The deformation and the bending moment of the fins are then also given by known relations and in this case we will also take care to remain fairly clearly below the critical load of Euler.

Dans tous les cas, il peut être avantageux d'utiliser des ailettes de section autre que rectangulaire pour obtenir une structure d'égale résistance, par exemple par extrusion. On peut ainsi utiliser des ailettes à profil parabolique tronqué ou bien à profil trapézoïdal. Le calcul se fait alors selon les mêmes lois.In all cases, it may be advantageous to use fins of section other than rectangular in order to obtain a structure of equal resistance, for example by extrusion. It is thus possible to use fins with a truncated parabolic profile or else with a trapezoidal profile. The calculation is then done according to the same laws.

La figure 3 illustre un procédé de fabrication d'un revêtement suivant l'invention, dans lequel des rubans 18 disposés sur des bobines 14, ici au nombre de 4, réparties autour de l'âme 7 à revêtir, sont amenés en coïncidence sur leurs bords, sur une largeur correspondant à la hauteur désirée pour les ailettes, leurs bords étant ensuite soudés à ce niveau. Pour ce faire, l'âme est animée d'un mouvement de translation axial suivant la flèche F et les rubans 18 voient leurs bords mis en contact en 21 au fur et à mesure de leur déroulement, au niveau de rainures 20 ménagées sur la face interne d'un cylindre-guide 19 dont l'axe est l'axe de déplacement de l'âme 7. A la sortie du cylindre-guide 19, sont disposées des têtes ou des paires de têtes de soudure venant effectuer la soudure des portions de ruban mises en contact par les rainures 20. Il va de soi qu'on peut utiliser seulement un ruban posé par exemple en hélice et réaliser de ce fait une seule ailette.FIG. 3 illustrates a method of manufacturing a coating according to the invention, in which ribbons 18 disposed on coils 14, here 4 in number, distributed around the core 7 to be coated, are brought into coincidence on their edges, over a width corresponding to the desired height for the fins, their edges then being welded at this level. To do this, the core is animated by an axial translational movement along arrow F and the ribbons 18 see their edges brought into contact at 21 as they unfold, at the level of grooves 20 formed on the face internal of a guide cylinder 19, the axis of which is the axis of movement of the core 7. At the outlet of the guide cylinder 19, heads or pairs of welding heads are arranged which weld the portions of ribbon brought into contact by the grooves 20. It goes without saying that it is possible to use only a ribbon laid, for example in a helix, and thereby make a single fin.

A titre de variante, le cylindre 19 est remplacé par des paires de rouleaux d'axes parallèles à l'axe de déplacement de l'âme 7 du câble, et qui sont espacés de manière à pincer deux épaisseurs de rubans 18. Par exemple, on utilisera deux paires de rouleaux par rainure 10 et la soudure des portions de ruban sera effectuée entre les deux paires de rouleaux.As a variant, the cylinder 19 is replaced by pairs of rollers with axes parallel to the axis of movement of the core 7 of the cable, and which are spaced so as to pinch two thicknesses of ribbons 18. For example, two pairs of rollers will be used per groove 10 and the tape portions will be welded between the two pairs of rollers.

Un revêtement 8 fabriqué à partir de rubans soudés au niveau de leurs bords aura la forme représentée à la figure 2 c'est-à-dire que les bords de ruban 18 sont solidaires sur une partie plus mince correspondant à environ deux épaisseurs du ruban jusqu'à une portion en saillie formant une portion plus épaisse 9 qui se présente sur un diamètre légèrement supérieur au diamètre moyen du revêtement 8.A covering 8 made from ribbons welded at their edges will have the shape shown in FIG. 2, that is to say that the edges of the ribbon 18 are integral on a thinner part corresponding to approximately two thicknesses of the ribbon up to 'to a projecting portion forming a thicker portion 9 which has a diameter slightly greater than the average diameter of the coating 8.

Un revêtement 8 pourvu d'ailettes élastiques 10 peut être réalisé par extrusion dans une boudineuse à travers une tête dont le profil correspond à celui du revêtement 8. Ainsi, à la figure 4 a on a représenté en coupe partielle un revêtement 8 réalisé par extrusion et comportant des ailettes 10' profilées depuis une portion large 22, qui les raccordent au contour cylindrique du revêtement, jusqu'à une portion étroite 23 au niveau de leurs extrémités par exemple selon un profil parabolique tronqué ou trapézoïdal.A covering 8 provided with elastic fins 10 can be produced by extrusion in a extruder through a head whose profile corresponds to that of the covering 8. Thus, in FIG. 4 a, a covering 8 produced by extrusion has been shown in partial section and comprising fins 10 'profiled from a wide portion 22, which connect them to the cylindrical contour of the coating, to a narrow portion 23 at their ends, for example according to a truncated or trapezoidal parabolic profile.

Les ailettes 10 peuvent être longitudinales. Elles peuvent être aussi hélicoïdales ou à pas alterné : dans le cas d'une fabrication à partir de bandes, l'ensemble des bobines 14 et le cylindre-guide 19, ou les paires de rouleaux, seront animés d'un mouvement correspondant autour de l'axe de déplacement de l'âme 7; ou bien l'âme 7 sera mise en rotation autour de son axe de déplacement, par exemple en faisant tourner une bobine qui la reçoit et/ou un touret qui la débite, autour d'un axe perpendiculaire à son axe longitudinal. Dans le cas d'une fabrication par extrusion, on fera tourner l'appareillage d'extrusion ou bien, comme mentionné ci-dessus, l'âme du câble.The fins 10 can be longitudinal. They can also be helical or with alternating pitch: in the case of manufacture from strips, all of the coils 14 and the guide cylinder 19, or the pairs of rollers, will be given a corresponding movement around the axis of movement of the core 7; or else the core 7 will be rotated about its axis of movement, for example by rotating a coil which receives it and / or a reel which delivers it, around an axis perpendicular to its longitudinal axis. In the case of manufacture by extrusion, the extrusion apparatus will be rotated or else, as mentioned above, the core of the cable.

Le centrage du câble dans son enveloppe peut être effectué en utilisant une enveloppe pourvue d'une seule ailette, de préférence hélicoïdale ou à pas alterné. Une hélice ou un pas alterné aura un pas assez court, par exemple de l'ordre de grandeur du diamètre du revêtement, de telle sorte que l'excentrement de l'âme du câble, qui sera au pire compensée un demi-pas plus loin par la reprise élastique de l'ailette, soit corrigé efficacement.The centering of the cable in its envelope can be carried out using an envelope provided with a single fin, preferably helical or with alternating pitch. A propeller or an alternating pitch will have a fairly short pitch, for example of the order of magnitude of the coating diameter, so that the eccentricity of the cable core, which will be compensated at worst half a step further by the elastic recovery of the fin, is corrected effectively.

Ainsi qu'il apparaît de la description et des exemples ci-dessus, l'espace ou jeu existant entre la partie cylindrique du revêtement 8 et l'enveloppe 12 est supérieur à l'espace ou au jeu qui est toléré entre l'âme d'un câble et son enveloppe extérieure dans la technique des câbles en général, et notamment dans le cas d'un câble tel que décrit dans le brevet français 1 593 816. Ce jeu plus important est mis à profit pour l'auto-centrage que permet le revêtement selon l'invention.As appears from the description and examples above, the space or clearance existing between the cylindrical part of the covering 8 and the casing 12 is greater than the space or the clearance which is tolerated between the core of a cable and its outer casing in the cable technique in general, and in particular in the case of a cable as described in French patent 1,593,816. This greater play is used for the self-centering that the coating according to the invention allows.

Selon une variante de réalisation de l'invention, la profondeur de la ou des ailettes est variable périodiquement entre une valeur maximale et une valeur minimale, cette variation étant déphasée dans le cas de plusieurs ailettes. Ainsi, dans le cas d'une fabrication à l'aide de rubans posés en long (cf: figure 3), les tourets 14 sont montés sur un excentique dont l'excentrement correspondra à l'amplitude de variation de la profondeur des ailettes et dont la vitesse de rotation définira le pas de la variation, en relation avec la vitesse de défilement de l'âme du câble. Dans le cas d'une réalisation par extrusion, on utilisera une boudineuse pourvue d'un profil d'extrusion variable au niveau des ailettes, la variation étant commandée par exemple par un excentrique.According to an alternative embodiment of the invention, the depth of the fin or fins is periodically variable between a maximum value and a minimum value, this variation being out of phase in the case of several fins. Thus, in the case of manufacture using ribbons laid lengthwise (cf. FIG. 3), the drums 14 are mounted on an eccentric, the eccentricity of which corresponds to the amplitude of variation of the depth of the fins and the speed of rotation of which will define the pitch of the variation, in relation to the speed of travel of the cable core. In the case of production by extrusion, a extruder will be used provided with a variable extrusion profile at the level of the fins, the variation being controlled for example by an eccentric.

La variation de profondeur des ailettes permettra de disposer une surlongueur de l'âme du câble à l'intérieur de l'enveloppe, l'âme du câble revêtue de sa gaine à ailettes se positionnant en hélice du fait de la variation périodique de la profondeur des ailettes, et par conséquent autour d'une position moyenne correspondant à un centrage. Lors du déroulage du câble en vue de sa pose, la traction sur l'enveloppe produira un léger allongement de celle-ci (par exemple de l'ordre de 0,5%), ce qui fait qu'après déroulage, les longueurs du câble et de l'âme se trouveront égales. L'âme du câble ne sera alors plus forcément centrée ce qui n'est que de peu d'importance pour un câble posé. En effet, seules des contraintes mécaniques (ovalisation de l'enveloppe) et/ou thermiques seront subies par le câble, et pour celles-ci le centrage précis de l'âme n'est pas important.The variation in depth of the fins will make it possible to have an extra length of the core of the cable inside the envelope, the core of the cable coated with its fin sheath being positioned in a helix due to the periodic variation of the depth. fins, and therefore around an average position corresponding to centering. When unwinding the cable for laying, the pull on the envelope will produce a slight elongation thereof (for example of the order of 0.5%), so that after unwinding, the lengths of the cable and core will be equal. The core of the cable will no longer necessarily be centered, which is only of little importance for a laid cable. Indeed, only mechanical (ovalization of the envelope) and / or thermal stresses will be undergone by the cable, and for these the precise centering of the core is not important.

L'invention ne se limite pas aux modes de réalisation décrits . ci-dessus. Ainsi, il n'est pas nécessaire que les ailettes soient réalisées dans le même matériau que la partie cylindrique du revêtement 8. D'autre part, les ailettes, qu'elles soient ou non réalisées dans le même matériau que le revêtement 8 en sa partie cylindrique, peuvent être renforcées par un ou plusieurs rubans élastiques.The invention is not limited to the embodiments described. above. Thus, it is not necessary that the fins are made of the same material as the cylindrical part of the coating 8. On the other hand, the fins, whether or not made of the same material as the coating 8 in its cylindrical part, can be reinforced with one or more elastic tapes.

Claims (9)

1. Revêtement destiné--à assurer le centrage d'une âme de câble dans son enveloppe et comportant au moins une ailette, caractérisé en ce que ladite ailette (10) est élastique.1. Coating intended - to ensure the centering of a cable core in its envelope and comprising at least one fin, characterized in that said fin (10) is elastic. 2. Revêtement selon la revendication 1, caractérisé en ce que ladite ailette (10) comporte une portion épaisse (9,22) qui la raccorde au contour cylindrique du revêtement (8) et devient plus mince au niveau de son extrémité.2. Coating according to claim 1, characterized in that said fin (10) has a thick portion (9,22) which connects it to the cylindrical contour of the coating (8) and becomes thinner at its end. 3. Revêtement selon l'une des revendications 1 ou 2, caractérisé en ce qu'il comporte au moins un ruban (18) dont les bords sont solidarisés entre eux sur une partie de leur largeur.3. Coating according to one of claims 1 or 2, characterized in that it comprises at least one ribbon (18) whose edges are secured to each other over part of their width. 4. Revêtement selon l'une des revendications précédentes, caractérisé en ce qu'au moins une ailette est en polypropylène ou en polyéthylène haute densité ou en polyester.4. Coating according to one of the preceding claims, characterized in that at least one fin is made of polypropylene or high density polyethylene or polyester. 5. Câble caractérisé en ce qu'il comporte un revêtement selon l'une des revendications précédentes, et une enveloppe (12) entourant celui-ci.5. Cable characterized in that it comprises a coating according to one of the preceding claims, and an envelope (12) surrounding the latter. 6. Câble selon la revendication 5, caractérisé en ce que la hauteur d'au moins une ailette (10) est supérieure au jeu existant entre l'âme et l'enveloppe du câble.6. Cable according to claim 5, characterized in that the height of at least one fin (10) is greater than the play existing between the core and the envelope of the cable. 7. Dispositif selon l'une des revendications précédentes, caractérisé en ce qu'au moins une ailette (10) est de hauteur périodiquement variable.7. Device according to one of the preceding claims, characterized in that at least one fin (10) is of periodically variable height. 8. Procédé de fabrication d'un câble comportant un dispositif de centrage de son âme, caractérisé en ce qu'il consiste à former un revêtement en amenant en coïncidence les bords d'au moins un ruban sur une largeur donnée autour de l'âme du câble, à solidariser entre eux lesdits bords sur au moins une partie de ladite largeur de manière à réaliser au moins une ailette élastique (10), et à disposer une enveloppe (12) autour du revêtement (8).8. A method of manufacturing a cable comprising a device for centering its core, characterized in that it consists in forming a coating by bringing the edges of at least one ribbon in coincidence over a given width around the core. of the cable, securing together said edges over at least a portion of said width so as to produce at least one elastic fin (10), and to have an envelope (12) around the covering (8). 9. Procédé selon la revendication 8, caractérisé en ce que ladite largeur donnée est périodiquement variable, de manière à faire varier la hauteur de l'ailette (10).9. Method according to claim 8, characterized in that said given width is periodically variable, so as to vary the height of the fin (10).
EP19820400168 1981-02-06 1982-01-29 Sheathing for assuring the centering of a cable core in its covering, a cable containing such a device, and the method of its manufacture Expired EP0058112B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8102413 1981-02-06
FR8102413A FR2499757A1 (en) 1981-02-06 1981-02-06 COATING FOR PROVIDING THE CENTERING OF A CABLE CORE IN ITS ENVELOPE, CABLE COMPRISING SUCH A DEVICE AND METHOD OF MANUFACTURING THE SAME

Publications (3)

Publication Number Publication Date
EP0058112A2 true EP0058112A2 (en) 1982-08-18
EP0058112A3 EP0058112A3 (en) 1982-09-08
EP0058112B1 EP0058112B1 (en) 1985-10-09

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Application Number Title Priority Date Filing Date
EP19820400168 Expired EP0058112B1 (en) 1981-02-06 1982-01-29 Sheathing for assuring the centering of a cable core in its covering, a cable containing such a device, and the method of its manufacture

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Country Link
EP (1) EP0058112B1 (en)
JP (1) JPS57151904A (en)
CA (1) CA1188137A (en)
DE (1) DE3266727D1 (en)
FR (1) FR2499757A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR837031A (en) * 1937-04-30 1939-02-01 Materiel Telephonique Electric cables with coaxial conductors
DE937172C (en) * 1952-10-22 1955-12-29 Hirschmann Richard Fa Guide body for guiding high-frequency ribbon cables in pipes
GB918794A (en) * 1960-07-04 1963-02-20 Raymond Charles Mildner Improvements in or relating to co-axial cables
DE2421173A1 (en) * 1974-05-02 1975-11-20 Kabel Metallwerke Ghh HF coaxial cable with seam welded outer sheath - and solid insulation having expansion grooves, allows relief of pressure on sheath

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR837031A (en) * 1937-04-30 1939-02-01 Materiel Telephonique Electric cables with coaxial conductors
DE937172C (en) * 1952-10-22 1955-12-29 Hirschmann Richard Fa Guide body for guiding high-frequency ribbon cables in pipes
GB918794A (en) * 1960-07-04 1963-02-20 Raymond Charles Mildner Improvements in or relating to co-axial cables
DE2421173A1 (en) * 1974-05-02 1975-11-20 Kabel Metallwerke Ghh HF coaxial cable with seam welded outer sheath - and solid insulation having expansion grooves, allows relief of pressure on sheath

Also Published As

Publication number Publication date
EP0058112A3 (en) 1982-09-08
FR2499757B1 (en) 1983-09-09
EP0058112B1 (en) 1985-10-09
CA1188137A (en) 1985-06-04
JPS57151904A (en) 1982-09-20
FR2499757A1 (en) 1982-08-13
DE3266727D1 (en) 1985-11-14

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