FR2747829A1 - QUARTER COMPRISING ADDED ISOLATED CONDUCTORS - Google Patents

Abstract

The quad comprises four insulated conductors joined to each other to form an assembly comprising an external and curvilinear contour covered by a mass of dielectric material (3).

Description

The present invention relates to a fourth.

  There are known star quads used in telecommunication power lines. The star quads consist of two pairs of insulated conductors arranged at the top of a square, the two conductors of a

  same pair being arranged along a diagonal of the square.

  We know that the relative positioning of the conduits

  The tors forming a fourth star is essential to obtain specific capacitive and inductive couplings on which the quality of information transmission depends. These couplings must be carried out all the more precisely if it is desired to pass a large flow of information. Any lack of symmetry in the fourth results in parasitic couplings causing transmission errors which can only be corrected at the expense

  the speed of the information transmitted.

  Furthermore, to ensure satisfactory transmission, the conductors must be twisted and the pitch must be all the shorter as the requested flow is

Student.

  As an example, local networks are asked to transmit speeds of 150 Mbits / s or even

  more by signals at frequencies of 100 MHz or more.

  Are known, in particular from document FR-A-2,144,573, star quads comprising insulated conductors arranged in a cylindrical tube of extruded synthetic material. In order for the conductors to be properly held, in particular during the handling of wiring during which several fourths are brought together to form a cable, it is necessary that the tube is fairly rigid and thick enough. Quarters of known structure are

therefore of an ill-easy handling.

  Document DE-A-25 16 830 also discloses a fourth star in which non-insulated conductors are arranged in cells of a central rod and held in place in these cells by extruding around the conductors a dielectric material in which the conductors are drowned. As in the previous case, it is necessary to maintain the conductors according to a precise arrangement, to provide a large layer of dielectric material so that the quarter obtained is difficult to handle during a wiring operation associating several quarters . In addition, it is difficult to maintain the conductors in a precise position in the bottom of the cells during the extrusion operation of the

dielectric material.

  Furthermore, double pair quads are known in which four insulated conductors are twisted in pairs generally arranged in a double tube for

make a fourth.

  According to the invention there is provided a fourth comprising

  both four insulated conductors, in which the conduc-

  isolated teurs are joined to each other to form a unit comprising a curvilinear external contour covered

  by a mass of dielectric material.

  Thus, by following the curvilinear external contour of all the insulated conductors joined together, the mass of dielectric material ensures that the insulated conductors are held in a precise position and the fourth keeps flexibility due to the absence of dielectric material in the cavity central delimited by adjacent conductors.

  Other features and advantages of the

  vention will appear on reading the description which will

  follow a particular non-limiting embodiment of the invention, with reference to the attached single figure which is a very enlarged sectional view of a quarter star

according to the invention.

  Referring to the figure, the fourth star according to the invention comprises, in a manner known per se, four conductors 1 isolated by a solid or cellular dielectric material 2 such as polyethylene, polypropylene, polyvinyl chloride or a fluorinated polymer. When making the fourth star, the four insulated conductors are twisted while being guided for maintenance.

  nite precisely at the top of a square.

  According to the invention the insulated conductors are joined to each other to form an assembly having a curvilinear external contour which is covered by a mass of dielectric material 3, the central cavity 4 between the

  contiguous conductors not being filled with dielect material

  stick. The fourth according to the invention is for example produced by first forming all of the insulated conductors joined together. This set is obtained by twisting four insulated conductors, which can easily

  be obtained on a traditional wiring machine.

  The assembly thus obtained is then passed through an extrusion head while maintaining the assembly according to the desired twisting pitch. The insulated conductors then remain suitably joined to each other and the material

  extruded dielectric covers the curved external contour

  gene of the assembly without entering the cavity 4. If it is desired to make a watertight quarter it is also possible

  plan to introduce into the cavity 4 a waterproofing material

  chewiness such as a fat which ensures filling of the

  cavity 4 without reducing the flexibility of the fourth obtained.

  Of course, the invention is not limited to the embodiment described and it is possible to add to it

  variant embodiments without departing from the scope of the invention

  tion as defined by the claims.

  In particular, it is possible to provide a metallic strip laid lengthwise or helically around the quarter to improve the crosstalk with adjacent quads and to provide protection against radiation from the cable or

  against external disturbances.

  Although the invention was more specific-

  ment described in relation to a fourth star, it

  also applies to a fourth double pair.

Claims (1)

CLAIM   1. Quarter comprising four insulated conductors, characterized in that the insulated conductors are joined to each other to form an assembly comprising a curvilinear external contour covered by a mass of dielectric material (3).