FR2573241A1 - NEW PEST CONTROL YARN - Google Patents

Abstract

THE IGNITION WIRE CONTAINS, IN TWO LAYERS 4, 6 OF INSULATION, A LONGITUDINAL REINFORCEMENT ELEMENT 5. ACCORDING TO THE INVENTION, THIS ELEMENT 5 IS A TAPE LAYED BETWEEN THE TWO EXTRUSION OPERATIONS FORMING THE INSULATING LAYERS 4, 6 THE OPERATION IS MUCH SIMPLER AND FASTER THAN GUIDING, AND THE STRENGTH OF THE WIRE IS IMPROVED.

Description

1. The present invention relates to the manufacture of electric cables

  insulated, and more particularly the manufacture of anti-interference wires for ignition

  internal combustion engines for cars, boats and others.

  For reasons related to anti-parasitic effects, in the ignition cables of internal combustion engines the conducting wires are not aligned in the axis of the cable, but generally arranged helically around an absorbent core. For this reason, the tensile strength of the conductor cannot be used to participate in the tensile strength of the cable (so-called anti-interference "wire"). So we have to plan

  a covering, to stabilize the insulation, ensure resistance

  tensile strength of the cable, and more particularly obtain-

  establish a good connection between the ignition wire and the

terminal in which it is set.

  Usually an anti-parasite ignition wire

  comprises, from the center outwards; a sausage in ma-

  2. radio-absorbent and insulating material extruded on a guide wire; a conductor wound in a spiral around this tube; an insulating layer, extruded around the

  conductor, & possibly with the interposition of a

  insulating absorbent che on the conductor; braided braid on the insulation; then an external insulator. The object of the present invention is in particular to obtain a better connection between. the terminal and the ignition wire on which it is crimped, and this, for the usual operating temperatures, of the order of

1200C and beyond.

  As described above, the method used

  up to now consists of sheathing in two passes and incorporating between the two layers of insulation, in general, an elastomer (EPDM, hypalon or silicone) a

  braid, or covering, in polyester.-The disadvantage of this pro-

  yielded is that the braiding operation is very slow (50 m per hour approximately) therefore tCotteuse, due to the masses of the moving parts and the kinematics of the movements

  on machines. In addition, the values obtained for the eff-

  strong pull-outs are generally only one

  low margin at the minimum value required (6 to 7 daN next

before cases).

  In accordance with the present invention,

  this braiding operation by laying lengthwise, and in con-

  tinu, of a woven ribbon, poses that a simple tool allows

  perform at the same time as the second gain pass

ge, therefore in masked time.

  Other features of the invention appear

  will appear during the description which follows, given

  by way of nonlimiting example, with reference to the attached drawings, which will make it easy to understand how the invention

can be done.

  In the drawings: FIG. 1 represents an elevation view of the end, progressively stripped in stages, of an anti-parasite ignition wire according to the invention; and

  Figures 2a and 2b are plan views re--

  presenting samples of ribbons usable in

  the process of the present invention.

  -A typical cable according to the present invention is constituted as shown in Figure 1. It comprises a central wire 1 of any fabric, including

  the function is to allow, or facilitate the extru-

  sion and handling of sausage 2, which is general-

  Now formed of a ferrite-loaded resin or elastomer. On the flange is wound in a tight pitch helix a conductive wire 3, resistant or not depending on the applications. An insulating sheath 4 is extruded by

  above. It is obvious that if there was nothing else

  this ignition wire would have no mechanical resistance

  that, and in particular, the junction at the terminal would be too fragile. This is why generally a braid is formed around this first insulating layer, then a

  second insulating layer 6 is extruded on the braid.

  The braiding operation is very slow. We know that a double crown of hobioes turns around the cable

  in manufacturing, the Coils of a crown before alter-

  natively go inside and outside the boxes

  bines of the other crown. The advance is about 50 meters an hour. It is this speed that conditions all

the production line.

  In accordance with the present invention, a woven tape 5 is laid long and continuously. A simple tool allows this operation to be carried out at the same time as the second sheathing pass, therefore in masked time. The operation is comparable to that of laying a strip in the manufacture of a coaxial cable and does not bring any slowdown, since it can be

  executed faster than any of the

  very conductive extrusion or winding operations.

  4. The ribbon is woven in advance, instead of the braid

be manufactured on site.

  This ribbon has the following characteristics:

your: -

  - It must have a breaking strength of around 15 to 20 daN and an elongation of at least%;

  - the elements that constitute it (chain and tra-

  me) must resist the deformation undergone by the cable when crimping the terminal. For this reason, a polyester fiber will be used in preference to a glass fiber;

  - the meshes must be wide enough to

  put the two layers of insulation to adhere to each other,

  especially during the second extrusion operation.

  From this point of view, a ribbon 5a, with wide meshes., As represented in FIG. 2a, should be more suitable than a ribbon with tight fine wires 5b as represented in FIG. 25; - it can be adhered in order to improve its

  adhesion with the two layers of insulation.

  The width of the ribbon can be chosen so that the two 5 ', 5 "edges of the ribbon are juxtaposed with the edge

  on board or almost, once the ribbon is placed on the iso- sheath

  underlying mantle, or a slight overlap is possible.

  As regards the terminal, the part used for crimping can be:

  is increased in length, so as to improve

  rer tightening on the wire, - either provided with pins or punctures,

  round or triangular, and long enough to cross-

  tighten the outer layer of insulation and come to anchor

in the ribbon.

  The use of a ribbon, the weaving of which is already carried out before its introduction into the structure of the 5. cU.le provides a manufacturing advantage. It also brings an improvement to the cable structure, because the resistant elements of the tape are oriented parallel

  to the axis of the cable which allows more precise control-

  the elongation qualities of the cable, and the constraints

  your applied to the absorbent medium.

  In different areas of application of the ignition of internal combustion engines, we have already used

  covered cables. If the wrapping is for resistance

  tensile strength, or the strength of a connection to a terminal or any connector, the present invention

  advantageously applies in the same way.

  The method according to the invention provides a double

  advantage: economy of manufacture, improvement of pro-

  duit. This eloquently expresses that this process was not obvious since for several decades, the ignition wires had been manufactured with a

  braid without having thought of laying a ribbon.

  It goes without saying that the embodiments described and shown are only examples and that they could be modified, in particular by substitution

  technical equivalents, without going beyond the scope of the

vention. 6.

Claims (3)

  1 - Process for manufacturing electric cable   that, in particular anti-parasitic ignition wire, in which a longitudinal de-reinforcement element and of connection to a connection element such as thimble or   connector is placed between two extruded layers of ma-   insulating sheet, characterized in that a long and continuous layer is placed on the first layer of insulation (4)   woven tape (5), then extruded over a second   go to bed (6). insulating material.   2 - Method according to claim 1, character-   laughed in that the ribbon (5a) is a. wide stitches.   3 - Electric cable, especially ignition wire   anti-parasite age, obtained in accordance with the process according to one of claims 1 or 2.