FR2818819A1 - Cable anchorage and joint comprises tubular alloy body which is drawn over cable to form extended shrink fit sleeve on cable - Google Patents

Abstract

The sleeve comprises a tubular body (2) made of ductile metal alloy which is electrically conducting. An extended section (15) of the tubular body is capable of being deformed by drawing a ring along the surface. This process shrinks radially and extends axially the body in order to fit around a bare conductor cable. The sleeve comprises a tubular body (2) made of ductile metal alloy which is electrically conducting. On the outside of the tubular body there is a external channel (8) in which a drawing ring (9) is fitted. An extended section (15) of the tubular body is capable of being deformed, the deformation of this section ensuring the shrinking of this section around a conductor which has been introduced within the axial hole through the body. The channel receiving the drawing ring is formed near to one end of the body so that an extended chamber is formed in order to accommodate the strands of the inserted conductor. A support ring (6) is attached to the tube at the end remote from the external channel.

Description

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 The invention relates to a stretchable sleeve for suspension, anchoring or joining, for a bare composite electrical conductor.

 To reduce line losses in high voltage power lines, it is envisaged to use bare conductors called high temperature, made of composite materials and for example composed of a core formed by a complex of aluminum wires mixed with ceramic fibers, such as alumina, and peripheral strands formed by strands of aluminum or aluminum alloy.

 Currently, the suspension or anchoring of the electrical conductors, respectively under pylons or on a support, as well as the end-to-end junction of the conductors, is carried out with sleeves, compressible or stretchable, comprising a tubular body of metal alloy ductile and conductor of electricity, able to be connected to the conductor by plastic deformation on the latter. In the suspension or anchoring sleeves, this tubular body is secured to hooking means and, optionally, to a bypass plate.

 The British document GB-A-902 197 describes a first sleeve-conductor connection technique consisting in shrinking the tubular body on a composite conductor, by means of jaws with hexagonal internal profile, tightened radially on the conductor by a portable press. This technique does not allow perfect control of the radial forces exerted on the conductor, so that the constriction of the body on the conductor can, when it is composite, locally cause the rupture of the ceramic fibers of the core and weaken the resistance of the core to the longitudinal tensile forces exerted on it, by the arrow and the weight of the driver. In addition, after tightening, the conductor remains subjected to localized and heterogeneous tightening stresses.

 Another technique described in EP13655 consists in shrinking the tubular body on the conductor by drawing by means of a ring with frustoconical bore which, disposed in a groove of the tubular body, is displaced longitudinally over a part of the latter having an external diameter larger than the smallest inner diameter of the ring. If this technique is suitable for conductors in which the different strand layers and the core have similar elongation rates, it is not suitable for composite conductors with a ceramic core in which the elongation rate of the core is almost zero compared to that of the outer strand layers in

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 aluminum or aluminum alloy. Indeed, during the stretching of the tubular body by displacement of the frustoconical ring and because of the high rate of elongation of the aluminum alloy strands compared to the low elongation of the ceramic fibers of the core, the strands made of aluminum alloy subjected to the longitudinal component of the radial tightening force exerted by the moving ring elongate more than the fibers of the core, each forming a loop around this core and forming, together , a protrusion having several times the nominal diameter of the cable and called a bird cage.

 The object of the present invention is to provide a stretchable sleeve which can be shrunk on a composite conductor, without damage to its components, and without forming a bird cage.

entre, d'une part, cette gorge de dépôt et de départ de la bague d'étirage, et d'autre part, une gorge de fin d'étirage disposée en aval de l'extrémité interne de la zone d'emmanchement du conducteur dans l'alésage axial du corps, de manière à former, dans cet alésage axial et lors de l'étirage s'effectuant en allant de la gorge de départ à la gorge de fin d'étirage, une chambre d'accueil des brins du conducteur ayant le plus grand allongement. To this end, in the stretchable sleeve according to the invention, the groove for depositing and leaving the stretching ring is formed near one of the ends of the tubular body, while the stretchable part of the body extends

between, on the one hand, this groove for depositing and leaving the drawing ring, and on the other hand, a groove at the end of drawing arranged downstream of the internal end of the conductor fitting zone in the axial bore of the body, so as to form, in this axial bore and during the stretching taking place going from the starting groove to the end of stretching groove, a reception chamber for the strands of the conductor with the greatest elongation.

 Thus, the arrangement of a groove at the end of the stretching on the stretching body, beyond the fitting area of the conductor, makes it possible to form in the bore of the body a chamber in which the strands having the most large elongation, undergo no stress and can move freely, without affecting the connection of the tubular body with them and without forming unsightly protuberance. Furthermore, each strand of the conductor can be lengthened, depending on the friction, independently of the elongation of the neighboring strands.

 In one embodiment relating to the suspension and anchoring sleeves, the groove for depositing and leaving the drawing ring is formed near the end of the body which is opposite the end of this same body which is integral with the attachment means, while the end of stretching groove is disposed near the end of the body provided with the attachment means and above the reception chamber.

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 It should be noted that, with this anchoring or suspension sleeve, the stretching is carried out from the free end towards the end provided with the hooking means, that is to say in the opposite direction. of the direction of stretching described in document EP-A-13655.

 In its application to a junction sleeve, the end of stretching groove is disposed near the central part of the tubular body, and above a reception chamber which, formed in the central part of the bore of this body tubular, is common to the two halves of the body, halves each comprising, near their free end, a groove for depositing and leaving a ring, and, between this starting groove and the end of stretching groove, a portion stretchable, the shrinking of which is effected by moving the corresponding drawing ring, going from the starting groove towards the end of the drawing groove.

 Here again, the starting and ending stretching grooves are arranged in such a way that the constriction of each half of the sleeve is carried out in the direction of the reception chamber in order to accumulate therein the ends of the strands having a greater great elongation.

 The invention will be better understood with the aid of the description which follows with reference to the appended diagrammatic drawing representing, by way of examples, several embodiments of the sleeve according to the invention.

tandis que l'autre moitié est rétreinte sur le conducteur. FIGS. 1 and 2 are views in longitudinal section of a first embodiment of an anchoring sleeve, respectively before and after stretching,
FIG. 3 is a view in longitudinal section of another embodiment of an anchoring sleeve before stretching,
FIG. 4 is a view in longitudinal section of a junction sleeve, half of which is awaiting fitting of a conductor,

while the other half is shrunk on the conductor.

In the embodiment shown in Figures 1 and 2 and corresponding to an anchoring sleeve, the sleeve is essentially constituted by a tubular body 2, metallic and electrically conductive, and for example of aluminum alloy. This body 2 is traversed longitudinally by an axial bore 3. One of the ends of the body is constricted at 4 on the crenellated tenon 5 of a hooking ring 6. This end is also secured to a branch plate 7.

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Near its other end, the body has a groove 8 for receiving and leaving a drawing ring 9 in two parts. This ring has a frustoconical bore whose angle at the top has a value less than 150, and for example is 8. The groove 8, which is intended to receive and support the two parts of this ring as long as the sleeve has not been subjected to the drawing operation, is itself frustoconical, but with an even smaller angle, so as to facilitate the start of the stretching operation.

 The tubular body 2 is provided, near the end with the hooking means 6, with a groove 12 with a flat bottom, the diameter of the groove bottom is less than the smallest diameter of the ring 8. This groove, said end of stretching, is arranged substantially at the internal end, materialized by the dashed line 13, of the fitting area of the conductor 14 in the bore 3. In practice, the groove 12 is arranged so to be downstream of the fitting area.

 The part 15 of the tubular body disposed between the groove 8 and the groove 12 constitutes the part which is stretchable and curable on the conductor 14 fitted into the bore 3.

 To ensure the connection of the body 2 with the conductor 14, the ring 9 is moved on the part 15 in the direction of the arrow 16, that is to say going from the groove 8 to the groove 12. This movement of the ring creates radial forces on the material constituting the part 15 which is thus forced to be inserted between the external strands of the conductor 14, strands reflecting these radial forces on the axis 11 of the conductor.

pour exercer une contrainte qui, homogène sur toute la périphérie de la partie 15 mais aussi sur toute la longueur de cette partie, a une valeur suffisante pour assurer le rétreint de cette partie 15 sans endommager l'âme du conducteur. In known manner, the smallest diameter of the ring is determined

to exert a stress which, homogeneous over the entire periphery of the part 15 but also over the entire length of this part, has a sufficient value to ensure the constriction of this part 15 without damaging the core of the conductor.

direction des moyens d'accrochage 6 en étirant la partie 15. Ces forces d'allongement se communiquent aux brins externes et internes de l'âme 11 du conducteur 14, brins qui, selon leur taux d'allongement, s'allongent plus ou moins. Comme montré à la figure 2, les brins 19 ayant un plus grand allongement pénètrent progressivement dans une chambre d'accueil 17 qui est Simultaneously, by the conical shape of the bore 10 of the ring 9, but also by the movement of the ring 9, the latter exerts, on the part 15, longitudinal forces which tend to move its constituent material in

direction of the attachment means 6 by stretching the part 15. These elongation forces are communicated to the external and internal strands of the core 11 of the conductor 14, strands which, depending on their elongation rate, elongate more or less . As shown in FIG. 2, the strands 19 having a greater elongation progressively enter a reception chamber 17 which is

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 formed in bore 3, below the groove 12. To improve the perception in the drawing of the differential elongation between metal strands and strands with ceramic fibers, the strands are shown parallel to the longitudinal axis of the bore 3, even when they are in a helix. The length S of the reception chamber 17 is determined so that, at the end of stretching, that is to say when the ring 9 occupies the position shown in phantom in Figure 2, the strands having the most large elongation, are completely contained in the chamber 17, without coming into contact against any abutment means.

 Thanks to this arrangement, each of the strands of the conductor moves freely as a function of its rate of elongation and of the stresses to which it is subjected and, by the orientation of this elongation in the direction of chamber 17, does not risk participating in the formation of a bird cage, that is to say an unsightly external growth and presenting technical problems.

 After stretching, the two-part ring 9 is removed.

 It appears from the above that the sleeve, according to the invention, makes it possible to obtain, by stretching, the desired radial stress to ensure the maintenance of the conductor, without risk of damaging the ceramic fibers of the core, while avoiding the consequences of the elongation differential between the components of the composite conductor.

 The embodiment shown in FIG. 3 differs from the previous one by the fact that the fixing means are no longer constituted by a ring 6, but by a plate 18, monolithic with the tubular body 2.

Except for this difference, the anchoring sleeve is in all respects similar to the previous one, since it includes, like it, a groove 8 for depositing and leaving the drawing ring 9, a stretchable part 15, a groove 12 for end of stretching, and a chamber 17 for receiving the strands of conductor having the greatest elongation.

 FIG. 4 represents a junction sleeve which is composed of two identical halves A and B arranged symmetrically with respect to a transverse axis x'x. Each of the halves comprises, as in the previous embodiments, a groove 8a for depositing and starting for a drawing ring 9, a stretchable part 15a, and an end of stretching groove 12a disposed downstream of the internal end 13a of the conductor engagement zone in the corresponding half A or B of the tubular body 2a.

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 Compared to the previous embodiments, the axial bore 3a is continuous over the entire length of the sleeve and therefore goes from the free end of half A to the free end of half B, passing through a central bearing 20 used to hold the sleeve during stretching.

 In FIG. 4, half A is shown in the standby position for engaging a conductor, while half B is shown after stretching, the conductor 14 being constricted by the tubular body 2a. In this junction sleeve, the reception chamber 17a is common to the two halves of the sleeve and therefore extends, over a length Sa on either side of the central part of this sleeve.

 As in the previous embodiments, the constriction is carried out by successively moving the drawing rings 9a going from the free end towards the center of the sleeve and provides the same results, namely assurance of obtaining a radial stress acceptable on the conductor, and in particular on its core, and elimination of any bird cage formation at one or the other of the ends of the junction sleeve.

d'éviter le cintrage des parties 15a, c'est-à-dire supprime tous risques de conformation du manchon en banane.Using draw rings also has the advantage

to avoid the bending of the parts 15a, that is to say eliminates all risks of conformation of the sleeve into a banana.

Claims (3)

 between, on the one hand, this groove (8, 8a) for depositing and leaving the drawing ring (9), and, on the other hand, a groove (12) for the end of drawing arranged downstream of the internal end (13) of the fitting area of the conductor (14) in the axial bore (3.3a) of the body (2.2a), so as to form, in this axial bore and during the stretching taking place from the starting groove (8) to the groove (12) at the end of the stretching, a chamber (17,17a) for receiving the strands (19) of the conductor having the greatest elongation.

 CLAIMS 1. Stretchable sleeve for suspension, anchoring or joining for electrical conductor, composite and bare, comprising a tubular body (2,2a) of ductile metal alloy and conductor of electricity, whether or not secured to hooking means (6) to a support, said body being provided, locally, on the one hand, with an external groove (8) constituting the deposition and departure zone of a drawing ring (9) with frustoconical bore (10) , and on the other hand, a stretchable part (15) of larger diameter than the small internal diameter of the ring (9) and whose deformation, by the movement of the ring (9), ensures the constriction of this part of the body on the conductor (14) introduced into the axial bore (3) of this body, characterized in that the groove (8) for depositing and leaving the drawing ring (9) is formed near one end of the tubular body, while the stretchable part (15,15a) of the body (2,2a) extends 2. Anchoring and suspension sleeve according to claim 1, characterized in that the groove (8) for depositing and leaving the drawing ring (9) is provided near the end of the body (2) which is opposite the end of this same body which is integral with the hooking means (6), while the groove (12) for end of stretching is arranged near the end of the

 body provided with attachment means (6) downstream of the reception chamber (17). 3. Junction sleeve according to claim 1, characterized in that the groove (12a) at the end of the stretching is arranged near the central part of the tubular body (2a) and above a reception chamber (17a ) which, formed in the central part of the bore (3a) of the tubular body, is common to the two halves (A and B) of the body, halves each comprising, near its free end, a groove (8a) for depositing and at the start of a ring (9), and between this groove (8a) and the groove (12a) at the end of stretching, a stretchable part (15a) whose shrinking is effected by displacement of the stretching ring ( 9) corresponding from the starting groove (8a) to the end of stretching groove (12a).