EP0786159B1 - Electrical contact terminal comprising prestressed terminal blades - Google Patents

Abstract

The electrical contact element is a single piece made of folded sheet metal. The front plug-in part consists of a frame with a base (22), two cut-out sides (24a, 24b) each forming a spring blade (32, 36) in a cantilevered configuration toward the front, a front flap (34) for maintaining the respective spring blade in a prestressed state, an upper part (26), a rear part for connection to a lead, including foldable lugs (16) for crimping onto the insulating covering of a lead. The blade (36) in the region of the upper part is formed from a rear extension thereof folded inwards and frontwards at 180 DEG C. The base (22) and the sides (24a, 24b) are single-walled.

Description

The present invention relates to contact terminals electric intended to receive male contact blades. It finds an important application in the modules of electrical connection intended to receive a layer of wires, of the kind used in particular in the automotive field.

The invention relates more particularly to the terminals of one-piece electrical contact in folded sheet metal, in accordance with the preamble of claim 1.

In such a terminal according to the prior art, for example one of those described in documents EP-A-0310487 and FR-A-2 703 520, the wall of the cage is at double wall on three sides, which has the advantage of giving to the cage great rigidity, but in return increases its size in all directions. We are looking for to reduce the distribution pitch of the contact terminals in connectors, which requires minimizing the transverse dimension of the terminal in the direction of alignment terminals.

The present invention aims in particular to provide a terminal of electrical contact of the kind defined above having small transverse dimensions, and constituting a compromise satisfying between space and rigidity.

To this end, the invention notably proposes a terminal for contact of the type defined above according to the characterizing part of claim 1.

We know (EP-A-0 147 076) electrical contact terminals single wall, but with an overall constitution completely different from that of the invention.

Thanks to this constitution, the size of the terminal in the direction parallel to the bottom and the ceiling can be scaled down. Because the cage constitution is preserved, the rigidity is still high. It is further increased by local doubling of the thickness of the ceiling.

To improve rigidity and facilitate manufacturing, the flat blank intended to make the terminal is advantageously cut so that the coming into contact of the two edges side of the blank in the front part is done in a side. More precisely, in an advantageous embodiment, a lower part on one side is attached to an edge from the bottom by a 90 ° fold while the other side, the ceiling and the upper part of the first side connect to the other edge of the bottom by a 90 ° fold parallel to the first.

The upper part can in particular end towards the rear substantially in the transverse extension of the 180 ° bend of connection of the corresponding contact blade and the terminal edge of the upper part takes support against the widening edge of the lower part.

The contact terminal according to the invention advantageously comprises a self-stripping or displacement rear part insulation, intended to make an electrical connection with the wires of a conductor ribbon or a flat cable.

The present invention also aims to provide a terminal of electrical contact of the type defined above having small transverse dimensions, and having means of displacement of insulation which reinforce the terminal and present less risk of spreading than previously known.

To this end, the invention proposes a terminal whose means displacement of insulator according to claim 6.

Due to the constitution of the fork, the branches of the latter resist separation more than wings belonging to two opposite flanks. Contact with the conductive part of the wire takes place on an increased surface.

To further increase the mechanical strength of the rear part, each branch of the fork may have at its end a transverse beak directed outwards, recessed in a notch on the respective side.

In an advantageous embodiment, allowing increase the wire retention effort, the wings are folded not only towards each other, but also slightly forward. Folding at an angle of 120 ° approximately will generally give satisfactory results. However, it is still possible to carry out a simple folding at 90 °.

Such insulation displacement means can be used in terminals having a constitution of the front part different from that mentioned above.

Still other aspects of the invention will become apparent from reading of the description which follows of a particular mode of embodiment, given by way of nonlimiting example.

• la figure 1 est une vue en élévation d'une borne selon un mode particulier de réalisation de l'invention ;
• la figure 2 est une vue en perspective depuis l'avant de la figure 1 ;
• la figure 3 est une vue de dessus de la borne de la figure 1 ;
• la figure 4 est une vue en coupe suivant la ligne IV-IV de la figure 3 ;
• la figure 5 est une vue en courbe suivant la ligne V-V de la figure 4 ;
• la figure 6 est une vue en perspective depuis le dessus montrant une constitution possible de la partie arrière de la borne ; et
• la figure 7 est une vue développée d'un flan découpé destiné à constituer la borne.

The description refers to the accompanying drawings, in which:

• Figure 1 is an elevational view of a terminal according to a particular embodiment of the invention;
• Figure 2 is a perspective view from the front of Figure 1;
• Figure 3 is a top view of the terminal of Figure 1;
• Figure 4 is a sectional view along line IV-IV of Figure 3;
• Figure 5 is a curved view along the line VV of Figure 4;
• Figure 6 is a perspective view from above showing a possible constitution of the rear part of the terminal; and
• Figure 7 is a developed view of a cut blank intended to constitute the terminal.

The electrical contact terminal 10 shown in Figures 1 to 6 can be viewed as having a front part intended to receive a male contact blade 12 and a rear part constituting a crimp barrel.

The front part of terminal 10 has a cage shape having a bottom 22, two sides 24a and 24b and a ceiling 26. In the illustrated embodiment, the entire side 24b is formed by bending at 90 ° an original blank, around one of the longitudinal edges of the bottom 22. The ceiling 26 is connected to side 24b by another 90 ° fold. On the other hand, the other side 24a is not entirely formed by folding back 90 ° from the original blank around the other bottom edge 22. The blank has a rectangular notch making an edge 28 appears. This notch is filled with a fraction of the original blank located on the other side of the bottom 22, folded 90 ° around the edge of the ceiling 26. In general, the contact line 30 between the two fractions on side 24a will be approximately in the midplane on this side.

The bottom 22 is cut so as to constitute a first elastic contact blade 32 intended to rest on the blade male contact 12 when it is inserted. An extension from the bottom folded backwards constitutes a flap 34 of holding the blade 32 in preload.

A second electrical contact blade 36, arranged in face of the blade 32, is integral with the ceiling 26. It is formed from a rear extension of the blank which is folded 180 ° and curved. The rear part of the blade 36 as well formed is supported against the ceiling. Its front part has substantially the same shape as that of the blade 32 and it, too, is retained in prestress by a flap 34. A window 37 can be cut in the ceiling 26 and extend over the sides to receive a finger locking.

To facilitate the manufacture of the terminal, the edge 28 is advantageously substantially in the same transverse plane that the extension foot which will give birth to the terminal elastic 36, and therefore the 180 ° fold.

The rear part of the contact terminal has two tabs or tabs 16 which, before mounting a wire, are are located in the extension of sides 24a and 24b. They are intended to be crimped or shrunk onto the insulation of a conductor, which may belong to a ribbon cable. In sufficiently separating the sides of the front part and the rear part, it is possible to make them so simple by cutting a blank and folding.

The rear part of the terminal shown as an example further comprises, in front of the legs 16, means for displacement of insulation in two locations staggered along of the terminal.

These means include two wings 38 extending the sides 24a and 24b, formed by cutting the blank and folding at 90 ° around orthogonal lines at the bottom, oriented perpendicular to the direction of elongation of the contact and delimiting a slot of width adapted to that some thread. The edges opposite the wings can be parallel over their entire length or give the slot an entrance convergent. To facilitate the folding of the wings 38, the notches in the blank which separate them from the bottom 22 can protrude these wings forward.

In the illustrated embodiment, only the bottom of the terminal remains between the wings and the crimping lugs 16.

The insulation displacement means of the terminal shown also include a fork 40 placed in front of the wings 38 and parallel to these wings. This fork is made up by a fraction which is cut in the part of the blank which gives rise to the floor and which is folded 90 ° around of a transverse line 42. This fraction can have a width as it rests on the sides when the bollard is finished. In addition, the fork can be extended at its upper end by transverse nozzles 44 directed outwards. On the terminal finished these spouts are embedded in notches 46 made in the upper edge sides 24a and 24b. The installation thus carried out keeps the fork 40 in its nominal position even when subjected to the pressure of the insulation of a wire which is pressed in the direction of arrow f of the figure 6.

To further increase the resistance to deformation of the back, channel-shaped, bottom and sides can be deformed by punching in several places 48, as shown in Figures 1 and 3.

To constitute a terminal of the kind shown in the figures 1 to 6, we first cut a blank of the kind shown in Figure 7, where the portions which then give rise to elements of the complete terminal are designated by the same Reference number. We see in this figure that none narrow slit is only to be practiced between fractions which are, on the complete terminal, separated by a fold. The cut is relatively simple and can be executed even in sheet metal very slim.

The successive folds to be carried out emerge from the constitution of the terminal and can be carried out on a transfer line.

So that the connection between the spouts 44 and the sides 24a and 24b are comparable to an embedding, we give advantageously at the notches 46 a width slightly less than the thickness of the strip which constitutes the terminal and at least one of the edges of the notches is slightly deformed, as shown in Figure 6, before folding the sides. At during a final manufacturing step, the folding tool exerts efforts in the direction of the arrows f1 to pinch the pins 44.

By way of example, it can be indicated that the invention has allowed to make terminals intended to receive male tabs having a cross section of 0.63 x 0.63 mm, capable of be spread in steps of 2.50 mm (one tenth of an inch). A 0.15 mm strip construction is possible.

The contact terminal can be used in modules connectors of known constitution, for example of the kind described in (the document FR-A-2 703 520).

The invention is susceptible of numerous variants of production. The rear part of the terminal may have a constitution different from that which has been described is shown in Figure 6. One can for example use insulation stripping means of the kind described in the document FR-A-2656469 or FR-A-2 703 520. It is also possible to provide a rear part having just a pair of crimp tabs on the insulation a wire and a pair of crimp tabs on the conductor. The terminal can also be used on a discrete wire.

Similarly, the front part of the terminal may have a constitution different from that which has been described, by example that described in document EP-A-0310487.

Claims (12)

1. Electrical contact terminal made of a single piece of folded sheet,

   having an insertable front part constituting a cage formed from a bottom (22), two sides (24a, 24b) and a roof (26), the bottom and the roof being cut in order for each to form a resilient contact blade (32, 36), cantilevered towards the front, and of a front flap (34) for retaining the respective blade in a prestressed state,

   having a rear part for connection to a wire, having fold-down tabs (16) for crimping onto the insulation of a wire,

      characterized in that the blade (36), forming part of the roof, consists of a rear extension of the roof, folded through 180° towards the inside and towards the front, and in that the bottom (22) and the sides (24a, 24b) are single-walled.
2. Terminal according to Claim 1, characterized in that a lower part of a first side (24a) is joined to one edge of the bottom (22) by a 90° fold while the other side (24b), the roof (26) and the upper part of the first side (24a) are joined to the other edge of the bottom by a 90° fold parallel to the first 90° fold.
3. Terminal according to Claim 2, characterized in that the said upper part terminates towards the rear approximately in the transverse extension of the 180° fold for connection to the corresponding contact blade and the terminal edge of the upper part bears against the edge of a widening of the lower part.
4. Terminal according to Claim 1, 2 or 3, characterized by a window (37) for housing a locking finger made in the roof.
5. Terminal according to any one of the preceding claims, characterized in that the rear part carries insulation displacement means (38, 40).
6. Terminal according to Claim 5, characterized in that the insulation displacement means comprise:

   on the one hand, two flanges (38) formed by folding terminal parts of the two sides (24a, 24b) of the cage towards each other, the said flanges defining a slot parallel to the sides,

   on the other hand, a fork (40), placed in front of the flanges and parallel to these flanges, formed by folding a rear extension of a bottom (22) of the cage through 90° about a transverse line, and bearing on the sides.
7. Terminal according to Claim 6, characterized in that the arms of the fork (40) have, at their end, an outwardly facing transverse nose (44) fitted into a notch (46) in the respective side (24a, 24b).
8. Terminal according to Claim 7, characterized in that the said notches (46) have a width which is slightly less than the thickness of the fork.
9. Terminal according to Claim 6, 7 or 8, characterized in that the two flanges (38) are folded, towards each other and also forwards, so as to increase the retention force on the wire.
10. Terminal according to Claim 9, characterized in that the flanges (38) are folded through approximately 120°.
11. Terminal according to any one of Claims 6 to 10, characterized by recesses at the base of the flanges, at the point where they join the bottom (22).
12. Terminal according to any one of Claims 6 to 11, characterized, between the flanges (38) and the fork (40), by puncturing elements (48) on the bottom and on the sides.

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