EP1851835B1 - Female electrical contact comprising spring contact plates - Google Patents

Abstract

The invention relates to a female electrical contact including a housing which is cut and folded from a metal strip and which includes at least one contact plate which extends along the longitudinal axis (A) of the housing and which is equipped with a section that is in contact with a complementary contact pin. According to the invention, the contact plate includes part for connecting to the housing and a free end. The invention also includes a spring element which is cut from the extension of the contact plate prior to folding, such as to form a counter plate after folding. The spring element and the plate are provided, for example, on either side of the above-mentioned connection part.

Description

The present invention relates to a female electrical contact with spring contact blades.

The female contacts comprising a cage of quadrilateral section and provided with internal contact blades made by folding cutting a metal strip intended to make an electrical contact by cooperation with complementary pin contacts frequently include a spring element additional to the contact blade allowing to guarantee a sufficient contact pressure when coupling said female contacts and said pin contacts.

This spring element, which is applied to a portion of the contact blade, is either cut and folded into the metal strip for making the cage, or a spring element attached and inserted into the cage.

An embodiment of a female cage contact provided with internal spring contact blades comprising a complementary spring element is described in the document JP 9-232021 .

According to an embodiment described in this document, a contact blade pre-cut spring in the metal strip and folded from the rear to the front of the cage is prestressed by a spring element itself cut into the strip and folded from the front of the cage to the back of the cage.

In an alternative embodiment described in this document, a spring element, cut and folded from the back to the front, comes, when inserting a pin contact, resting on a folded contact blade of the back to the front.

This spring element is however spaced from the contact blade in the absence of the complementary pin contact.

According to this same embodiment, a folded structure from the front of the cage protects the blade during the introduction of a complementary pin contact. This structure is however not in contact with the free end of the blade.

The document US-B-6428366 shows a contact according to the preamble of claim 1.

The present invention aims to improve the spring leaf contacts in particular by ensuring a significant contact pressure by applying a preload on the spring blade, while retaining reduced outside contact dimensions and limiting the number of folds required.

To do this, the present invention mainly relates to a female electrical contact with a cut cage folded from a metal strip and comprising at least one contact blade, extending along a longitudinal axis of the cage, and provided with a contact section with a complementary contact pin, the contact blade comprising a connection part to the cage and a free end, characterized in that it comprises a spring element cut in extension of said contact blade before folding and forming against -blade after folding.

More particularly, the spring element and the blade are formed on either side of the connecting portion.

Thus, the blade and the blade against are cut in extension in the same sheet, one being folded over the other to be fully enclosed in the cage after folding.

• en figure 1: une vue de côté en coupe d'un contact femelle selon l'invention en vis à vis d'une broche complémentaire;
• en figure 2: une vue en perspective trois quart arrière du contact de la figure 1;
• en figure 3: une partie de feuillard découpée pour réaliser le contact de la figure 1;
• en figures 4A à 4D: des vues en perspective de stades successifs de réalisation du contact de la figure 1;
• en figures 5A à 5C: des vues de côté des stades de fabrication des figures 4C et 4D et d'une étape de repli d'un rabat selon l'invention.

Other features and advantages of the invention will be better understood on reading the following description of a nonlimiting exemplary embodiment of the invention with reference to the figures which represent:

• in figure 1 : A side view in section of a female contact according to the invention with respect to a complementary pin;
• in figure 2 : a three-quarter perspective view of the contact of the figure 1 ;
• in figure 3 : a part of strip cut to realize the contact of the figure 1 ;
• in Figures 4A to 4D : perspective views of successive stages of realization of the contact of the figure 1 ;
• in FIGS. 5A to 5C : side views of the manufacturing stages of Figures 4C and 4D and a folding step of a flap according to the invention.

The cage electrical contact represented in figure 1 is intended to receive a complementary pin 4. This cut contact bent from a metal strip 1 shown in FIG. figure 3 comprises at least one contact blade 2, extending along a longitudinal axis A of the cage.

The contact blade is made in the strip consisting of a metal alloy having good electrical characteristics and a sufficient stiffness so that the blade has spring qualities guaranteeing a pressure of important contact on the complementary spindle 4. The alloys corresponding to these characteristics are, for example, nickel-copper or non-nickel-plated copper-aluminum alloys.

The contact and in particular the cage are made by successive folding of the strip 1.

The cage is formed by successive bends in sequence and, following the folding on the Figure 4A there is in the following order: a strip in which the blade and the blade are made, a strip intended to produce an upper wall 14 carrying the blade, a strip for a first lateral wall 15 of the cage, a lower wall 13 of the cage carrying a boss 12 and a strip intended to form at least part of a second side wall 16 of the cage.

The folding of the strip 1 begins with the formation of the curvature of the blade 2 and against the blade formed by the spring element 7 as shown in FIG. Figures 4B and 4C .

Then, the connecting portion 5 is folded laterally on a wall 14 of the cage once the element bears against the blade 2, as shown in FIG. Figures 4D .

From this moment the blade and the blade against are protected by the wall 14 and formed permanently, the against blade being trapped between the wall 14 and the blade 2.

According to this embodiment, the blade and the blade against are cut on an outer edge of the strip to be found after folding fully enclosed in the cage.

The rest of the folding is then performed around a lower wall 13, which is extended by a segment 21 for connecting a cable, by a first folding forming, on one side of this lower wall 13, the upper wall 14 carrying the blade, a second folding forming a first lateral wall 15 and, on the other side of this lower wall 13, at least part of a second lateral wall 16.

To make the electrical contact, the blade is provided with a contact section 3 with the complementary contact pin 4.

In the case of the example described, the pin, once introduced into the cage, is pinched between the contact blade and a boss 12 made in a floor 13 of the cage, this floor extending in this example by the part of connection 21 to a traditional cable that will not be more explicit here.

The contact blade 2, made by folding cut, is finally disposed under the wall 14 opposite the floor of the cage 13.

In the direction of the longitudinal axis of the cage, from the rear to the front, the blade comprises an end or part 5 of connection to the cage, a contact section 3 and a free end 6, the contact section 3 being an intermediate portion of the blade between the end of connection to the wall 14 and the free end 6.

The contact according to the invention comprises, in parallel with said blade 2, a spring element 7 comprising an end 8 of connection to the cage, which in the example is attached to the connection part 5 to the cage of the blade 2, an intermediate portion 9 along the blade and a free end 10 applied to a face of the blade opposite to the face of the blade intended to come into contact with the complementary pin.

This spring element is shaped to push the blade in the direction perpendicular to the longitudinal axis A of the cage towards the inside of the cage.

The female contact 2 according to the invention further comprises a flap 11 which extends the front of the wall 14 of the cage carrying the blade 2 and which is folded towards the inside of the cage so that the flap is applied on the free end 6 of the blade to bring it back to said wall 14.

According to the example described, the contact comprises a single blade 2 facing the boss 12 disposed on a wall 13 of the cage opposite the blade 2 relative to said axis A.

The cage must have a good resistance in bending or torsion and, according to a particular embodiment, the wall 14 carrying the blade comprises at least one folded lateral part 18, 19, represented in particular in figure 4D and forming a complementary element of the wall 16.

In addition, to close the cage, said second side wall 16 is extended laterally by a crenel 17, embedded between two folded side portions 18, 19 of the wall 14 carrying the blade to stiffen the cage.

Returning to figure 1 it is noted that the spring element 7 comprises, close to its connection end to the cage, a boss 20 bearing against the wall 14 of the cage carrying the blade 2.

This boss 20 makes it possible to fix with precision the point of articulation of the spring element 7 and thus to limit the fluctuations of the stiffness of the latter, which could appear because of the manufacturing differences.

Advantageously, the spring element 7 is curved with a radius of curvature smaller than the radius of curvature of the blade, which, at least in the absence of complementary pin contact, makes it possible to ensure that the spring element bears against the blade 2 by its free end 10 and not by any portion of its length, so that the active length of the spring element is well determined.

In addition, to increase the contact pressure, the contact section 3 with the pin contact 4 is reduced. To do this, the contact section of the blade has a curved contact zone.

According to the example, the end 10 of the spring element 7 is applied to the blade 2 in the rear part of said contact zone with respect to the insertion direction D of the complementary pin contact 4.

According to the example, the blade and the spring element extend from the rear towards the front (the spindle receiving part) of the cage the connection ends of the spring and the blade 5, 8 being rear ends of the spring and the blade, the free ends of the spring and the blade 6, 10 extending from the rear of the cage towards the front of the cage.

The realization of the cage is more particularly represented in Figures 4A to 4D and 5A to 5C .

The realization of the female contact is specified below.

Starting from the cutting of the strip represented in Figure 4A in the first place and according to the Figure 4B , the blade is curved in shape and folded to deviate from the plane of the strip.

This folding is performed so that the blade deviates from a distance C1 of the wall 14 carrying the blade 2, this distance being represented on the Figure 5A in side view.

As represented in Figures 4C and 5A the spring element is then bent and folded 180 ° to constrain the blade to move away from the wall by a distance C2 greater than the distance C1.

In this position, the spring member applies pressure to the blade forcing it into the cage.

In the particular case of the example shown, the blade assembly, spring element is folded at 180 ° on the lower face of the wall 14 as shown in FIG. figure 4D to position the blade and the spring element as shown in Figure 5B .

Finally and according to the Figure 5C , the flap 11 is applied against the end 6 of the blade on the face opposite to the face of the blade receiving the spring element to bring the blade to a distance C3 of said wall, the distance C3 being less than the distance C2 so that the pressure applied to the blade by the spring element is increased and so that the position of the blade in the cage is established precisely with respect to the internal dimensions of the cage and the insertion axis D of the pin contact 4.

After these operations, the strips to form the walls of the cage are folded in sequence and the slot 17 is itself folded to close the cage.

Thus, the contact according to the invention remains small because of the small number of necessary bends, the contact pressure is important because of the presence of a counterblade made by a spring element trapped between the wall bearing the blade contact and the latter and the folded cage has no openings or protruding parts that can injure the joints through which the contact must be positioned in the context of applications of automotive connections.

The invention is not limited to the example shown and is applicable in particular to a contact having two contact blades facing each other.

Claims (11)

1. A female electrical contact with housing cut and folded from a metal sheet (1) and comprising at least one contact plate (2), extending along a longitudinal axis (A) of the housing, and, provided with a section (3) for contact with a complementary contact pin (4), the contact plate comprising a part (5) for connecting to the housing and a free end (6), having a spring element (7) cut out in lengthways extension of said contact plate before folding and forming a counter-plate after folding, characterized in that free ends (6, 10) of the spring and the plate extend, after folding, from the back to the front of the housing.
2. The contact according to claim 1, further characterized in that spring element (7) and plate (2) are created on either side of connecting part (5).
3. The contact according to claim 1 or 2, further characterized in that the spring element comes to be supported on the plate by means of folding at 180°.
4. The contact according to one of claims 1 to 3, further characterized in that connecting part (5) is folded laterally onto a wall (14) of the housing after the spring element rests on plate (2).
5. The contact according to one of claims 1 to 4, further characterized in that it has a single plate (2) facing a boss (12) positioned on a wall (13) of the housing opposite plate (2) with regard to said axis (A).
6. The contact according to claim 5, further characterized in that the housing is created by folding metal sheet (1) around a lower wall (13) to form an upper wall (14) bearing the plate and a first lateral wall (15) on one side of this lower wall (13) and at least part of a second lateral wall (16) on the other side of this lower wall (13), the plate and the counter-plate being cut out of an outer edge of the metal sheet so as to be entirely enclosed in the housing after folding.
7. The contact according to one of the preceding claims, further characterized in that spring element (7) is imprisoned between a wall (14) of the housing and plate (2) and, near the part for connecting to the housing, has a boss (20) for support against wall (14) of the housing bearing plate (2) and forming a stiffener.
8. The contact according to one of the preceding claims, further characterized in that spring element (7) is curved along a radius of curvature smaller than the radius of curvature of the plate so that, at least in the absence of the complementary contact pin, only a free end (10) of the spring element rests against plate (2).
9. The contact according to one of the preceding claims, further characterized in that contact section (3) of the plate has a curved contact zone, end (10) of spring element (7) being applied onto plate (2) at the rear part of said contact zone relative to direction (D) for insertion of complementary contact pin (4).
10. The contact according to one of the preceding claims, further characterized in that said ends for connecting the spring and the plate (5, 8) are rear ends of the spring and the plate.
11. The contact according to one of the preceding claims, further characterized in that it has a flap (11), extending the front of a wall (14) of the housing bearing plate (2) and is folded back toward the inside of the housing, the flap being applied onto free end (6) of the plate to bring it towards said wall (14) counteracting the force applied onto plate (2) by spring element (7).

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