FR2835959A1 - Flat cable for electromagnetic applications, uses ribbon cable with transverse grooves in insulation to allow cable to fold into zigzag shape as it twists - Google Patents

Abstract

The flat cable (1) is made up of multiple rectangular section conductors (2) embedded in an insulating material (1a,1b) to form a flat ribbon cable. Sloping transverse grooves in the insulation, regularly distributed along the length of the cable, allow the cable to fold, so that it can be twisted into a zigzag.

Description

<Desc / Clms Page number 1>

The present invention relates to a flat cable.

 For certain electromagnetic applications, for example, "Airbag" system, pretensioner for seat belts and others, it is necessary to twist the supply conductors which excludes the possibility of using flat cables, that is to say flat conductors embedded in a thickness of insulating material. However, such flat cables are often more practical to use, because they are laid out in layers and allow easier wiring.

 One of the aims of the present invention is to allow, for these electromagnetic applications, the use of flat cables.

 The flat cable according to the invention is of the type comprising a series of flat, parallel conductors embedded in a thickness of insulating material, said flat cable being characterized in that it is bent along a series of transverse lines so as to obtain a substantially zigzag configuration.

 Such a flat cable, thus bent, can replace the twisted conductors normally used.

 According to a particular characteristic, the transverse lines are parallel and inclined in order to form, along the two edges, alternate internal acute angles.

 Finally, according to a last characteristic, the folding is carried out in the same direction along all the folding lines.

<Desc / Clms Page number 2>

 The invention will now be described in more detail with reference to particular embodiments given by way of example only and shown in the accompanying drawings.

 Figure 1 shows a flat cable used to make twisted cables.

 Figure 2 shows in plan the formation of fold lines for the realization of a twisted flat cable.

 Figure 3A is a perspective view showing the flat cable being folded.

 Figure 3b is a plan view showing the finished twisted flat cable.

 Figure 4 shows schematically in plan an alternative embodiment of a flat cable twisted during its development.

 Figure 5A and 5B respectively show the embodiment and the flat twisted cable obtained from the bending shown in Figure 4.

 In Figure 1, there is shown a flat cable 1 with two faces 1a and 1b and comprising a series of parallel flat conductors 2 embedded in a thickness of insulating material.

 According to the embodiment of FIGS. 2,3A and 3B, on the face 1a of the flat cable 1, virtual fold lines 4,5, 6,7 and 8 are drawn which extend

<Desc / Clms Page number 3>

 transversely to the longitudinal axis of the ribbon cable.

 Lines 4 and 5 delimit between them a band 9, lines 5 and 6 a band 10, lines 6 and 7 a band 11 and lines 7 and 8 a band 12, the reference 13 designating an extreme band.

 In this embodiment, the flat cable is folded along line 4 so that the strip 9 is applied against the face 1a and folded in opposite directions along the line 5 so that the face 1b of the strip 10 is folded against the side Ib of the strip 5.

 The flat cable is folded along line 6 so that the strip 11 is, on the side of the side 1a, partially applied against the strip 10 on the side of the side 1a, while along the line 7, the flat cable is folded so that the strip 12 is, on the side of the side Ib, applied against the strip 11 on the side of the side Ib.

 The strip 13 is folded along the line 8 and applied against the strip 12 on the side of the face 1a.

 The flat cable can thus include a series of folds taking, after line 8, the same folds as those corresponding to lines 4,5, 6 etc.

 Figures 4,5A and 5B show an alternative embodiment in which the flat cable designated as a whole by the reference 15 has two faces 15a and 15b.

<Desc / Clms Page number 4>

 The flat cable 15 comprises a series of lines 16 to 20 extending parallel and transversely so as to form, on the side of the two longitudinal edges of said flat cable, internal alternate angles 21, 22 of the order of 20 to 300.

 The different lines delimit between them bands 23 to 28.

 The flat cable is folded so that the strip 24, after folding along the line 16, is applied by the face 15a against the face 15a of the strip 23, the strip 25 after folding along the line 17 against the strip 24 on the side of the face 15a and so on, that is to say that all the strips are folded in the same direction along the fold lines. A substantially zigzag configuration is thus obtained, the re-entrant and salient angles of which can be more or less pronounced depending on the inclinations given in lines 16 to 20.

 Of course, the invention is not limited to the embodiments which have just been described and shown. Many detailed modifications can be made without departing from the scope of the invention.

Claims (3)

1. Flat cable comprising a series of parallel flat conductors (2), embedded in a thickness of insulating material, characterized in that it is folded along a series of transverse lines (4,5, 6,7, 8 ) so as to obtain a substantially zigzag configuration.  2. Flat cable according to claim 1, characterized in that the transverse lines (16 to 20) are parallel and inclined so as to form, along the two edges, alternate internal acute angles (21,22).  3. Flat cable according to claims 1 and 2, characterized in that the folding is carried out in the same direction along all the folding lines (16 to 20).