EP0812034B1 - Female electrical contact terminal having a reinforced transition zone - Google Patents

Abstract

The connector is formed from a single thin metal sheet. The connector has a rear section which can be crimped onto an electrical wire (20) and an extension forming a squared section (26) with a central male plug receptor. The connector section has a window hole (70) at the start of the extension, leaving an outer joining section similar to a saddle shape.

Description

The present invention relates to a terminal one-piece female electrical contact, sheet metal cut and formed, intended to receive a male contact. It relates more particularly to a terminal of the type comprising a front body in the form of a cage having a bottom, an upper wall, and two side walls having each an internal tab which is connected to them by a 180 ° fold and which has a front part overhang constituting a contact blade.

We already know contact terminals of the above type defined, which can be manufactured by cutting, folding, forming and possibly rolling a wafer strip much more economically than low-cut terminals. In return, the contacts existing in cut and formed sheet metal have a certain number of drawbacks. If the contact blades are initially resting against each other and oppose a high force at their spacing, which is favorable to ensuring high contact pressure a good quality electrical connection, the strength is important and there is a risk difficult introduction. This first drawback can become serious if many contact terminals are provided in the same connector. If, on the contrary, the blades are initially separated, the pressure exerted by each contact blade can in some cases be insufficient to ensure a good electrical connection.

A solution to this technical problem has been brought in patent application FR-A-2621180 which describes a female contact terminal which at the same time guarantees a satisfactory electrical connection and provides guidance of male contact during its introduction. Therefore each side wall has a folded flap at the front inward, holding the contact blade in bending preload in a position where it is out of contact with the other contact blade.

Many of the bent sheet metal contact terminals existing to date also present a risk crushing during handling in production or from harness manufacturers. This is particularly the case for female electrical contact terminals in the form of a cage but single wall like those described in patents US-A-4453799 or EP-A-0697752, or those having non-prestressed contact blades which do not participate not to the stiffness of the cage as described for example in patent application FR-A-2627020.

Single or double wall electrical terminals must also resist any tearing action or shearing of the metal strip constituting them. This is how, due to the cuts, forming, folding of these thin sheets, the intersections of cutting lines can shear, tear under the action of a lateral mechanical thrust exerted on a wall or parallel to it.

This risk is particularly high in thinned areas such as the transition area between the rear part for connection to an electric wire and the front part constituted by the cage, or even in the cage windows provided to allow attachment of the terminal in the plastic boxes of the connectors receiving these bounds.

Finally, the risk of the forceful introduction of a male contact, the sizing would be greater than the internal dimensions of the cage and which would therefore apply pressure, on the contact blades, higher than the pressure of the elastic deformation threshold of the metal constituting the contact blade, which would cause definitive deterioration of the blade having then reached its plastic deformation threshold.

These drawbacks become particularly important when, for economic reasons, the manufacturers looking for solutions to reduce costs without penalizing quality, plan to reduce the thickness of the strip constituting the single plate of electrically conductive metal.

The invention thus relates to a contact terminal female electric obtained from a single plate of electrically conductive metal having a portion rear allowing its connection by crimping with a electrical wire, a transition zone and a front part in the form of a cage made up of a bottom, two side walls provided with means guiding a male contact during its insertion and means of fixing this cage in housings of connection, of two upper half-walls for which the walls of the cage extend into the part close to the transition zone by two branches square-shaped.

The branches of the square can also define with the side walls an opening allowing the passage of a blocking device secondary.

In a particular embodiment the brackets can define a passage between them which positions the end of the wire to be crimped.

la figure 1 est une vue en perspective montrant une borne de contact électrique femelle selon l'invention;

la figure 2 est une vue en plan d'une plaquette destinée à être pliée pour constituer la borne de l'invention;

les figures 3A et 3B sont des vues en coupe de la partie avant en forme de cage;

la figure 4 est une coupe partielle d'une borne positionnée dans un isolant;

les figures 5 et 5A sont deux vues en perspective avec une partie arrachée montrant la borne de la figure 1;

les figures 6 et 6A sont deux vues en perspective avec une partie arrachée montrant un autre détail de la borne de la figure 1;

la figure 7 est une vue en plan d'une plaquette destinée à être pliée pour constituer une borne de l'art antérieur.

The invention will be better understood on reading the following description of a particular embodiment of the invention, given by way of non-limiting example. The description refers to the accompanying drawings, in which:

Figure 1 is a perspective view showing a female electrical contact terminal according to the invention;

Figure 2 is a plan view of a plate intended to be folded to form the terminal of the invention;

FIGS. 3A and 3B are sectional views of the front part in the form of a cage;

Figure 4 is a partial section of a terminal positioned in an insulator;

Figures 5 and 5A are two perspective views with a part broken away showing the terminal of Figure 1;

Figures 6 and 6A are two perspective views with a part broken away showing another detail of the terminal of Figure 1;

Figure 7 is a plan view of a plate intended to be folded to form a terminal of the prior art.

The terminal whose final constitution is shown in Figures 1 and 3 to 6, made from a plate of the kind shown in Figure 2, is intended to be inserted in a connector housing whose constitution general can be classic. Terminal 10 is one piece, it can be viewed as having a front body 11 intended to receive a male contact 12 and a part rear or crimp barrel 14. These two parts are separate by a transition zone 15. The barrel 14 has two sets of tabs 16 and 18, respectively intended for be crimped onto the core and the sheath of an electric wire 20.

The body of terminal 10 has a cage shape having a bottom 22 and two sides 24. Each side 24 is double. It includes an outer wall 26 and a tongue internal 28. Each external wall 26 is produced by 90 ° folding of the original plate according to one of the lines 30 indicated by dashed lines in FIG. 2. The internal tongue 28 is connected to the external wall 26 by a 180 ° bend along the edge indicated at 32 in the figure 2. The set of two walls and tabs 26 and 28 have a fold at right angles along the lines designated by 34 in Figure 2.

As seen in Figure 2 each tab internal 28 is only connected to the external wall corresponding 26 as in its rear part. The part front of each internal tab 28 thus constitutes a contact blade 29 elastic support generating pressure on the surface of male contact 12 when this is inserted.

In another embodiment not shown, each contact blade 29 could be split by a slit over part of its length from the free end, this allows a more regular support but however, this splitting is not essential. Mon contacts (or both) could be devoid of slot. Conversely, it would be possible to plan more a slot in each contact blade.

Between the wall 26 and the tongue 28 a part of wall close to the 180 ° fold constitutes a half ceiling of cage. In the embodiment shown, the cut of the original plate leaves tabs 40 in abutment support against one another and constituting a continuous ceiling in the cantilevered area of the slats 29. This last solution limits the risks for hooking terminals together when they are bundled or loose and provides protection complete with contact blades.

Each contact blade 29 advantageously has a shape of the kind shown in Figures 3 and 4. The part in overhang, forming electrical contact, represents a little more than half the total length of the internal tab 28 and it is shaped so as to have an inward camber. It presents plus a thickened bend 27 directed towards the other blade of contact, in the immediate vicinity of its free end. The elastic force due to the bending of the contact blade 29 and tending to bring two blades close together, is absorbed by a flap 46 of the outer wall 26 corresponding, folded back. This flap 46 which also allows the guiding of the male contact during its insertion, thus retains the contact blade 29 in bending preload in a position close to the outer wall 26 to which it is linked, i.e. in a position where she is out of touch with the other contact blade 29 opposite it. We see on the Figure 1 that the fold of the flaps is in front of the end edges of the side walls of the cage and is of rounded shape, which facilitates the introduction of the terminal in the insulator 51 of a connector housing, not represented, and limits the risks of deterioration of this insulating. To further reduce the risk when the introduction, the edges of the bottom and the ceiling can be softened.

In the outer walls 26 are provided openings 50 intended to allow the immobilization of the terminal in an insulator 51 using a finger lock 52 which can have any of constitutions used at present. In the mode shown in FIG. 4, this finger is made up by an elongated beam formed during the molding of the insulator, having a lug 53 directed inwards of the insulation cell and which can engage in the window 50. Because the beam 52 extends forward from lug 53, it is possible to unlock the terminal by driving a tube through the front passage 54 of the insulation (delimited by an annular lip having a breach allowing the mounting of the tongue 52), this tube coming to slip between the side of the terminal and the beam. Due to the symmetrical location of the two windows 50, the terminal can occupy either of two positions symmetrical in the cell of the insulation.

As can be seen in Figures 2 to 4, the window 50 has on one of its sides a portion of wall which during production allows the realization a deformation of the strip so as to form a fold 55. This fold 55 defines a shoulder whose surface 56 is designed to cooperate with the upper bearing surface 57 of lug 53 allowing the fixing of the terminal in the insulation cell.

It will be noted that the end of this deformation 55 is oriented inward and constitutes a stop acting on the outer surface of the contact blade 29 so as to avoid any risk of exceeding the elastic limit of said blade.

This layout, combined with the layout described above according to which the flap 46 retains in bending preload contact blade 29, allows thus to control the contact pressure of the blade on continuous male contact, i.e. throughout the life of the terminal, each time it is inserted.

The advantage of such an arrangement allows thanks to the two deformations, namely the flap 46 and the fold 55, the definition of a game delimiting the displacement of the contact blade 29 between a so-called passive position when it is retained by the flap 46 and that no male contact is inserted and a so-called active position when it limits the maximum gap of the blade under the effort created by the introduction of male contact.

As can be seen in FIG. 3, the folds 55 of the two external walls 26 converge in the same plane horizontal so that the contact points between the male contact 12 and the contact blades 29 on the one hand and between the contact blades 29 and the folds 55 else share define a space that eliminates any possibility introduce a male contact not conforming to the dimensions of the female terminal.

As described in Figure 4, the fold 55 has a double orientation. The first folding orients the part of strip precut to the center of the terminal, then a second operation turns 180 ° the same part of strip towards the outside of the terminal thus reinforcing the mechanical strength of the shoulder formed by fold 55. It will also be noted that the lower surface 56 of the fold 55 has a large bearing surface on the surface upper 57 of lug 53 which avoids any risk of shear of the wafer despite the decrease in the thickness of the strip. This surface 56 is substantially greater than the bearing surface 57 so as to that the force exerted is as homogeneous as possible on these surfaces and does not generate an overhang.

The respective plans of the bearing surfaces complementary 56 and 57 define an angle α with the plane perpendicular to the longitudinal axis of the terminal, so that their respective opposite slopes create a self-engagement effect between the terminal and the insulator. AT as an example the value of the angle α of the surface 57 of the lug is between 1 ° and 45 ° and so preferential has a value of 15 °.

Referring to FIG. 7, it will be noted that the windows 50a made in the terminal walls electrics of the prior art can obviously include the folds 55 although these walls are simple.

FIGS. 5 and 5A show a device for consolidation of terminal 10. Indeed, in order to compensate for the decrease in the thickness of the insert, the flap 46 has a width L substantially equal to the internal width defined by the terminal walls one folded over so that the side edges of the flaps 46 come to bear on the inner surface of the bottom and upper half-walls of the terminal. In addition these walls are provided with openings 60 in which engage pins 61 formed on the ends of the lateral edges of the flaps 46.

Besides the fact that the flaps 46 are thus solidly fixed, this consolidation of the cage forming terminal 10 also allows bracing of the walls of this cage and prevents accidental crushing.

Note that the fixing of the flaps 46 in the cage can be made by a single stud 61 provided on one or the other of the lateral edges of the flap 46.

Figures 6 and 6A show another arrangement able to reinforce the mechanical rigidity of the bollard by general.

Indeed between the front body 11 of the terminal 10 and the crimp barrel 14 there is a so-called transition zone 15 which can undergo deformations or misalignments prejudicial to the installation of the terminals in the insulators.

In these figures, we see that this area of transition is reduced in size. Indeed the walls 26 of the front body 11 are extended by two branches 71 and 72 in the form of a square which define with the bottom 22 and the wall 26 an opening 70 thus constituted by 4 sides cooperating together in the consolidation of this area partially hollowed out. Note that the opening 70 allows the introduction of any lateral locking device secondary of the terminal in a connector housing. he should also be noted that between the two brackets each arranged on a wall 26 is provided a space 73 allowing the positioning of the end of any wire to crimp slightly exceeding the required dimensions, thus avoiding this wire to push the terminal beyond the standards required for the correct positioning of the bollard in its insulator.

We will now give a brief description of a possible terminal manufacturing process according to the invention, making it possible to obtain the terminals in strips supply of an automatic crimping machine on sons.

In the case of the terminals of the invention intended for automotive, manufacturing is done by cutting and forming (folding) of alloy strips copper having a thickness of 0.29 mm. To a first workstation, the strip is cut to give birth of successive platelets of the kind shown in Figure 2, connected together by a connecting strip 66. The fold lines, indicated in dashed lines on Figure 2, can be marked with the press. The blades of contacts 29 are shaped by bending and striking and the flaps 46 are formed. As shown in Figure 4, there is advantageous to give to the set, constituted by the flaps and the free end part of the contact blades 29, a slope, for example of about 15 °, which facilitates the introduction of male contact.

The 180 ° fold between the tabs and the walls internal and external and the 90 ° fold inwards separating the part of the internal tongue belonging to the side and that belonging to the ceilings are formed; simultaneously the pins 61 penetrate into the windows 60 and the walls formed come into contact with the edges of the flaps 46.

The invention is not limited to modes individuals of achievement who have been represented and described as examples. She is likely to many variations. For example, it is possible to constitute a terminal whose faces are not exactly parallel but have a slope; a notch allowing the passage of the male blade at an angle, which is required for certain sealing embodiments, intended to receive a sealing tongue can be formed in front of the contact ceiling. He must be understood that the scope of this patent extends to such variants thus more generally than at all others remaining within the framework of equivalences, such as defined in the appended claims.

Claims (3)

1. A female electrical contact terminal obtained from a single plate of electrically conducting metal, comprising a back part (14) which makes possible its connection, by means of crimping, with an electric wire (20), a transition zone (15) and a front part in the form of a cage (10) consisting of a base (22), of two lateral walls (26) fitted with a means of guidance of a male contact (12) during its insertion and a means of fixing the said cage in connection casings, two upper half-walls, characterised by the fact that the walls (26) of the cage extend into the part which is close to the transition zone (15) by two branches (71,72) in the shape of a square.
2. A female electrical contact terminal according to Claim 1, characterised by the fact that the branches (71,72) of the square, constitute, together with the lateral walls (26), an opening (70), which allows the passage of a secondary locking device.
3. A female electrical contact terminal according to Claim 1, characterised by the fact that the squares together form a passage (73) in which is positioned the end of the wire to be crimped.

Images