FR2510295A1 - Electric cable having parallel conductors in insulating sleeve - uses plastics sleeve with hollow centre, with profile having curved walls matching curvature of corresponding conductor - Google Patents

Abstract

The electric cable has at least two geometrically parallel conductors embedded in an insulating sleeve (3). The insulating sleeve is mfd. from a plastics material and has a central hollow passage filled with air (4). The profile of the hollow passage has at least two curved sides, each side facing a conductor and having the same direction of curvature as the conductor it faces.

Description

 The present invention relates to improvements in cables conducting electricity and its main object is to provide a particularly new structure, which makes it possible to have inside the insulating body a hollow core, preferably filled with air, located practically in its center and preferably having a symmetrical shape.

 The state of the art reveals numerous structural arrangements of bipolar or multipolar electric cables, in which at least two conductors are coated with a single insulating sheath which separates them by insulating them electrically. Knowledge of the handling of plastic insulating sheaths has made it possible to develop a wide variety of forms of said insulating sheath and the analysis of the operational capacity in the means of extruding plastic materials has made it possible to develop the structure which constitutes the main object of the present invention; this structure being characterized in that a hollow core is introduced into the cable body which allows an extremely wide range of applications, impossible to obtain with known conductors.

 The cable object of the present invention retains good flexibility characteristics and can be used to power portable electric household appliances and workshop tools and be used in the aerial laying of lines intended to power lighting fixtures.

The hollow part of the conductor cable accommodates a small steel cable which acts as a load-bearing element for transmitting the weight of the device, leaving flexible insulated conductors their specific function of transporting energy.

 Furthermore, the cable which is the subject of the present invention facilitates the separation of each of the insulated conductors without damaging the other, which occurs frequently, with the cables known above all in household applications.

 The figures of the appended drawing, given by way of nonlimiting example, will make it easy to understand how the invention can be implemented.

 Figure 1 is a cross section of a bipolar cable according to the present invention.

 FIG. 2 also shows in section a variant of the cable shown in FIG. 1.

 Figure 3 is a cross section of a three-pole cable according to the present invention.

 Figure 4 is a view similar to the previous but it illustrates a four-pole cable according to the present invention.

 In all the figures, the same reference numerals denote identical or corresponding parts of the subject of the invention, whether it is a multipolar cable or the embodiments illustrated in FIGS. 1 and 2. This cable is consisting of two conductors 1 and 2 parallel to each other and surrounded by an insulating plastic sheath 3, in the center of which a continuous air core has been formed designated by the reference 4.

 The sheath 3 can have along its opposite joins two grooves having a Y-shaped section, referenced 5, and placed symmetrically with respect to the conductors 1 and 2. These grooves facilitate in a certain way. the positioning of the conductors when one has to separate one of them to make a connection.

 The core 4 has in section a structure symmetrical with respect to the longitudinal plane of the cable. While in the embodiment shown in Figure 1 the sheath 3 is cylindrical; we see that in Figure 2 this sheath is substantially flattened. The other characteristics remain, however identical to those just described; the outline or profile of the core retaining in both cases a rectangular shape, with two parallel rectilinear sides and two curved sides whose convexity is directed towards the interior of the core.

 In the embodiments illustrated in FIGS. 3 and 4, the cable corresponds respectively to a three- and four-pole conduction, by means of conductors 1, 1 ', 2, in the first case and of conductors 1, 1', 2, 2 ', in the second case, the number of grooves 5 increasing to three and four, respectively, in order to maintain the positioning which was alluded to previously with regard to the conductors.

 In the embodiment of FIG. 3, the core has a profile in the shape of a curvilinear triangle, the convexity of which is directed towards the interior of this core and, in the embodiment of FIG. 4, this profile has the shape of a quadrilateral with curved sides whose convexity is directed towards the interior of the nucleus.

Claims (3)

R E V E N D I C A T I O N S  1.- Improvements to cables conducting electricity consisting of at least one pair of electric conductors parallel to each other and placed in an insulating sheath, characterized in that this sheath (3) is made of plastic and has in its middle, a hollow core filled with air (4) placed between the two conductors (1, 2).  2. Improvements to cables conducting electricity according to claim 1, characterized in that the profile of the cross section of this core comprises, in the vicinity of the conductors (1,2) at least two curved sides whose convexity is directed towards the inside of the core (4).  3.- Improvements to cables conducting electricity according to claim ~ l, characterized in that the sheath (3) has along at least two generators, arranged symmetrically with respect to the conductors two grooves (5) in the form of V each having their apex directed towards the inside of the sheath (3).