EP0067780B1 - Bent end piece for electrical connections - Google Patents

Description

The present invention relates to bent end pieces, more generally called lugs, attached to the ends of electrical conductors to ensure the connection between a distribution source and a device for use. The invention relates, more particularly, to the bent ends of the above type which are used in the electrical ignition harnesses of engines and, more especially still, the ignition harnesses of internal combustion and spark ignition engines , especially for motor vehicles.

In the above technical field, it sometimes happens that the connection between the supply harness and either the coil, or the distributor, or the spark plugs, is effected by means of lugs or bent end pieces when the overall dimensions or the space available require it. Such end caps are completed by caps made of elastic material, such as an elastomer, provided for enclosing the conductive wire and the complementary connection member of the terminal to achieve a sealed association with infiltration and water splashes and having, in addition, an electrical insulation capacity.

The tips, which are currently used in the above framework, are parts obtained by stamping. Such end pieces have a bent L-shaped shape, generally at a right angle, comprising a branch for connection with the wire of the bundle and a connection branch. Such a conformation is, in particular, chosen so that the end pieces can also constitute traction members on which the forces to be developed are applied when it comes to disconnecting the wire with either the coil, the distributor, or the candle.

In general, such tips give satisfaction for the above functions. However, it has been found that such lugs do not lend themselves at all to the mounting of an elastomer cap when producing a bundle wire. Indeed, the angled shape at right angles prevents easy sliding of the cap on the terminal and the wire. To equip a complete wire, it is therefore mandatory to choose one of the following two methods.

The first consists of threading the bent cap onto the conductive wire, then ensuring the crimping or adaptation of a ferrule on the wire, then bringing the cap back into position on the ferrule. After which the assembly formed is checked and, if the wire thus formed does not meet the desired electrical characteristics, all of the elements must be rejected.

Such a solution is not satisfactory and cannot be accepted because, if an advantage lies in the simplest way of equipping the wire with a cap, it must be remembered that the caps of the two ends of a wire represent a cost important economic and that it cannot therefore be retained, nor envisaged, to reject such an assembly.

The second solution consists in crimping the lugs at the ends of a wire, then in threading the caps by subjecting them to a radial deformation sufficient to make them pass, without damage, the bent edge of the lugs.

If, from a technical point of view, such a way of proceeding can be envisaged, experiments have shown that it leads to imposing on the caps such a constraint that this results in permanent deformation of at least one of the ends of the caps. The functions of waterproofing and electrical insulation are thus altered, to the point of rendering the wire practically unusable. In addition, the edge of the bent terminal forms a cutting part causing the cap to tear.

Consequently, the current known methods do not allow the equipment of a wire to be produced satisfactorily.

The present invention aims to remedy the above drawbacks and proposes, for this purpose, a new terminal or a new elbow connector for electrical connection whose structure and conformation make it possible to obtain an easy relative sliding of the cap on the terminal, then on the cable.

The object of the invention thus makes it possible to carry out the manufacture of an ignition harness wire by first crimping the lugs or end caps on a wire, by controlling the electrical function of the latter and by equipping then such a wire, insofar as it meets the desired standards, with the protective and sealing caps.

It thus becomes possible to carry out mass production, at high flow rate, of conductive wires, in particular for ignition beams, by reducing any scrap to the minimum value and by ensuring the fitting and equipping of the elastomer caps so , if not easy, at least fast, safe, without risk of tearing and without risk of permanent deformation altering the quality of the finished product.

Another object of the invention is to provide a bent terminal or an electrical connection end piece which has mechanical resistance characteristics in relation to the particular application envisaged. In other words, the object of the invention is to provide a bent lug or an electrical connection cap capable of withstanding a tensile force applied to one of the constituent branches without permanent deformation of its own structure, nor degradation of the quality of crimping on the conductive wire, or of the electrical quality of contact of its connection branch.

• - possédant une section sensiblement égale à celle de la branche de connexion,
• - ayant un rayon de courbure, pris au niveau de la génératrice interne, de l'ordre de une à trois fois le diamètre de la branche de connexion, et
• - s'inscrivant dans le prolongement de ladite branche.

To achieve the above object, the invention is characterized in that the end piece comprises a connecting part formed by a tubular segment of generally toric shape:

• - having a section substantially equal to that of the connecting branch,
• - having a radius of curvature, taken at the level of the internal generator, of the order of one to three times the diameter of the connection branch, and
• - part of the extension of said branch.

• la fig. 1 est une perspective d'une des formes de réalisation de l'objet de l'invention,
• la fig. 2 est une perspective illustrant la position finale de l'objet selon la fig. 1 avant utilisation,
• la fig. 3 est une perspective montrant une variante de réalisation de l'un des éléments constitutifs de l'objet de l'invention,
• la fig. 4 est une perspective illustrant la position finale de l'objet selon la fig. 3 avant utilisation,
• les fig. 5 et 6 sont des perspectives montrant un développement de l'invention, de façon analogue à l'exemple selon les fig. 3 et 4,
• les fig. 7, 8 et 9 sont des perspectives illustrant trois autres réalisations possibles de l'objet de l'invention,
• la fig. 10 est une perspective mettant en évidence un détail de construction de l'objet selon la fig. 9,
• la fig. 11 est une vue en plan illustrant une découpe de métal permettant de réaliser, après formage, les objets selon les fig. 9 et 10.

Various other characteristics of the object of the invention emerge from the detailed description given below with reference to the appended drawings which show, by way of examples, embodiments of the object of the invention:

• fig. 1 is a perspective of one of the embodiments of the subject of the invention,
• fig. 2 is a perspective illustrating the final position of the object according to FIG. 1 before use,
• fig. 3 is a perspective showing an alternative embodiment of one of the constituent elements of the object of the invention,
• fig. 4 is a perspective illustrating the final position of the object according to FIG. 3 before use,
• fig. 5 and 6 are perspectives showing a development of the invention, similar to the example according to FIGS. 3 and 4,
• fig. 7, 8 and 9 are perspectives illustrating three other possible embodiments of the subject of the invention,
• fig. 10 is a perspective showing a construction detail of the object according to FIG. 9,
• fig. 11 is a plan view illustrating a metal cut-out making it possible to produce, after forming, the objects according to FIGS. 9 and 10.

According to the exemplary embodiment illustrated in FIG. 1, the angled electrical connection end piece, generally designated by the reference 1, comprises a branch 2, called crimping, on an electrical conductor 3, such as that shown in broken lines and forming part, for example preferred, of an ignition harness of a heat engine.

For the above purpose, the crimping branch 2 comprises a part 4, of substantially semi-cylindrical section, extended by two crimping tabs 5 which can be folded and folded down to be tightened and ensure mechanical resistance with the conductor 3 and indirectly make electrical contact.

The crimping branch 2 is connected, by a connecting part 6, to a branch 7 called connection, to a complementary terminal not shown. The complementary terminal can be carried, in particular, by a coil or an electrical distributor of an ignition system controlled by an internal combustion engine of the explosion type, such as those fitted to motor vehicles or by the olive. of a candle. For the above purpose, the branch 7 is preferably of the substantially tubular type comprising a part 7a elastically deformable in the radial direction to facilitate adaptation, mounting, maintenance, as well as the electrical connection with a complementary terminal which can be of the male or female type. The elastically deformable part 7a is constituted by two legs 8a which are separated with respect to two homologous legs 8b constituting a rigid part 7b for connection with the connecting part 6.

According to the invention, the connecting part 6 is constituted by a curved segment having, at least locally, a section substantially equal to that of the connecting branch 7. The curved segment is further defined by a radius R of center O which , taken at the level of the internal radius of the torus, has a measurement of the order of one to three times the diameter of the section of the branch 7. In addition, the curved segment fits exactly, preferably, in the extension of connection branch 7.

According to the illustrated embodiment, the curved segment, constituting the connecting part 6, is provided to delimit, at least locally, an envelope of generally toric shape. For this purpose, the connecting part or curved segment comprises a half-shell 9, of substantially semi-cylindrical section, which came directly from stamping during the shaping of the branches 2 and 7. The semi-cylindrical half-shell 9 has curved longitudinal edges 10 and 11, located in the same plane passing, substantially, through the base of the legs 5 and / or 8a-8b.

One of the edges of the half-shell 9, for example the edge 10, is associated with a complementary part constituted by a complementary half-shell 12, also of semi-cylindrical shape, which is connected, retained or attached to the half -shell 9 by means of a bridge 13. In the embodiment, the half-shell 12 is of the open semi-tubular type and results from a stamping operation carried out, starting from the same blank , to form the assembly described above.

The reconstitution of the connecting part 6 with a view to the formation of the toric envelope is obtained by subjecting the half-shell 12 to a folding operation in the direction of the arrow f,. This operation is carried out around or in association with the bridge 13, so as to bring the longitudinal edges 14 and 15 in abutment and in coincidence with the edges 10 and 11 of the half-shell 9.

This reconstruction phase is illustrated in fig. 2 which shows that the connecting part 6 is, in fact, in the form of a curved segment forming part of the extension of the branch 7 and defining, up to the conductor 3, a continuous toric envelope from the branch connection to conductor 3, in the example illustrated.

The above embodiment therefore makes it possible to thread an elastomeric cap on the branch 7 and to make it travel relative to the endpiece until it is partially threaded on the conductor 3. Indeed , the curved segment 6 does not have any protrusion or roughness having the effect of requiring a significant distension incompatible with the elastic limit of the cap or behaving like an element or obstacle of a constraining or blunt nature causing the deterioration of the cap by friction or by cutting or removal of the constituent material thereof.

The connection end piece, as described above, therefore makes it possible to envisage the manufacture of an ignition beam wire by initially proceeding to the cut to length of the conductor 3, with the crimping of the end end piece (s). , to control electrical properties ques then, then, to the mounting of the caps intended to definitively equip such a wire.

Fig. 3 shows an alternative embodiment according to which it is intended to constitute the curved segment 6 by means of a half-shell 16 of the semi-tubular toric type formed, as said previously, between the branches 2 and 7. According to this exemplary embodiment , the edges 10 and 11 of the half-shell 16 form grooves 17 and 18 opening outwards and formed, for example, by folding and cross-folding the edges 10 and 11.

The curved segment 6 also includes a complementary part formed by an independent half-shell 19 whose edges 14 and 15 are folded inwards, towards one another.

The two separate elements, as said above, are fitted by engagement of the folded edges 14 and 15 inside the grooves 17 and 18 by involving an elastic deformation operation either of the grooves 17 and 18, or of the edges 14 and 15. Fig. 4 shows that, in such an embodiment, the half-shell 19 makes it possible to reconstitute the curved segment so that the latter delimits an O-ring envelope, of substantially constant section, with the same characteristics as those of the previous example.

Fig. 5 shows an alternative embodiment according to which the curved segment 6 comprises a half-shell 20, of the type of that of FIG. 1. One of the edges of the half-shell 20, for example the outer lognitudinal edge 10, is associated, by a connecting bridge 21, with a half-shell 22 comprising a tubular semi-cylindrical part 23 extended by an appendage semi-frustoconical 24 which extends opposite the branch 2.

To reconstitute the segment 6 as described in the previous examples, the half-shell 22 is folded, in the direction of the arrow f ₁ , around the bridge 21, so that the part 23 is brought to locally reconstitute a toric tubular envelope with the half-shell 20. In this state, represented by FIG. 6, the free longitudinal edge 25 of the part 23 comes to bear on the internal longitudinal edge 11 of the half-shell 20.

Examination of fig. 6 shows that, during assembly, the routing of the cap causes the latter to cooperate with the appendix 24 during engagement on the connecting portion 6. The appendix 24 gradually restores the section of the segment 6 which can thus be crossed more easily by the cap.

Fig. 7 shows another exemplary embodiment according to which the curved segment comprises a half-shell 26, of the type of the half-shell 16. The half-shell 26 has edges 10 and 11 folded back towards one another in the diametrical plane. The reconstruction of the envelope, of substantially toroidal shape, defining the curved segment 6, is obtained, in this example, by using a complementary part formed by a section of toroidal rod 27 made of any suitable material, in particular semi plastic -rigid. The section of flange 27 comprises, in a substantially diametral plane, two longitudinal grooves 28 and 29 provided to receive the folded edges 10 and 11. The reconstitution of the toroidal envelope can be obtained by axial sliding of the section of flange 27 to the inside of the half-shell 26 or by radial penetration with elastic relative deformation of the material constituting the latter and / or of the edges 10 and 11. In certain cases, it may also be provided for a complementary crimping operation aimed at ensuring , by permanent deformation, the engagement of the pre-frayed edges 10 and 11 inside the complementary grooves 28 and 29.

An alternative embodiment of the form described above is shown in FIG. 8. According to this example, the element complementary to the half-shell 26 is constituted by a segment or section of helical spring 30 which is arranged, inside the shell 26, to be maintained and immobilized therein in order to reconstitute the 'O-ring constituting the curved segment 6. The immobilization of the segment or section of helical spring 30 can be obtained, in particular, by means of hooks 31 which are formed, from the longitudinal edges of the half-shell 26, in the connection zones between the latter and the branches 2 and 7. Preferably, the helical spring, chosen to assume the above function, is of the type of those having contiguous turns in a state of rest and in a rectilinear conformation.

Figs. 9 and 10 illustrate a particularly advantageous embodiment according to which the curved segment 6 always involves a half-shell 32 which is completed by tongues 33, of generally radial arrangement, of generally trapezoidal shape, the large base of each of which coincides with the longitudinal edge external to the center O, called, after shaping, to represent the edge 10 of the previous examples. These tongues 33 are rolled and folded over the longitudinal edge 11. FIGS. 9 and 10 show that the tongues 33 reconstitute together, with the half-shell 32, the toroidal envelope for connection between the branch 7 and the branch 2.

Fig. 11 shows an exemplary embodiment involving an L-shaped starting blank 34 in a plane. The blank 34 comprises, at a branch of the L, two legs 5 directed opposite one another with respect to an axis of symmetry A-A ', which form, with the common trunk 35, the branch of crimping 2. On the other branch of L, the common trunk 35 forms, with the legs 8a and 8b, the connecting branch 7. The outer periphery of the common trunk 35, between the legs 5 and 8b and shown in phantom , is extended by the tongues 33 in radial arrangement. The tongues 33 have a length such that after forming and rolling to reconstitute the O-ring, they come exactly on the edge 11.

It should be noted that the curved segment 6 is always constituted by a half-shell having a direct connection with the branches 2 and 7. In this way, this half-shell offers a resis high mechanical strength and can withstand, without risk of deformation, the tensile forces exerted on one of the branches or on the other in the direction of separation of the latter, in particular during maneuvers and manipulations aimed at ensuring the disconnection of branch 7 with respect to the complementary element of the distributor or of the member for using the electrical energy distributed.

By way of indication, the terminal described above is produced by cutting and stamping using a tool to be followed from a blank of suitable raw material, such as brass, zinc-plated steel, stainless steel.

In the example of figs. 7 and 8, the complementary part can be made of polyamide or of another plastic or elastomer material suitable as far as the flange 27 is concerned, and as steel or brass wire as regards the spring 30.

The invention is not limited to the examples shown and described above, since various modifications can be made without departing from its scope.

Claims (9)

1. Elbow-shaped electrical connector of the type comprising a securing branch (2) ensuring electrical connection with a conductor (3), a branch (7) substantially tubular and forming socket, elastically deformable radially for connection with a complementary terminal and an elbow-shaped part (6) of connection between said branches, characterized in that said connecting part is constituted by a curved segment defining, at least locally, a casing of general annular shape:

- of cross-section substantially equal to that of the connecting branch,

- of radius of curvature (R) taken at the level of the inner generating line of between one and three times the diameter of the connecting branch, and

- being an extension of said branch.

2. Connector according to Claim 1, characterized in that the curved segment is constituted by a half-shell (9) which is semi-annular and integral with the branches and is joined to a complementary part (12) reconstituting the casing.

3. Connector according to Claim 2, characterized in that the complementary part is constituted by a semi-annular half-shell, connected (13) to the half-shell integral with the branches with which it defines a tubular casing which joins up with the connecting branch.

4. Connector according to Claim 3, characterized in that the connection between the two half-shells is made by at least one bridge part (13).

5. Connector according to Claim 2 or 3, characterized in that the complementary part is formed by a half-shell (19) constituted by an independent part having longitudinal edges (14, 15) which are turned inwardly and cooperate with complementary grooves (17, 18) provided on the longitudinal edges of the half-shell integral with the branches.

6. Connector according to Claim 2, characterized in that the complementary part is formed by a half-shell constituted by a semi-cylindrical portion (23) extended by a half-truncated appendage and connected by at least one bridge part (21) to the half-shell integral with the branches.

7. Connector according to Claim 2, characterized in that the complementary part is formed by a coil spring portion inserted and immobilized in the half-shell integral with the branches.

8. Connector according to Claim 2, characterized in that the complementary part is formed by a helical spring portion (30) inserted and immobilized in the half-shell integral with the branches.

9. Connector according to Claim 1 or 2, characterized in that the curved segment is constituted by a half-shell integral with the branches and by tongue pieces (33) extending from the outer edge of said half-shell, said tongue pieces being rolled over towards the center of the torus until they contact with the inner edge of said half-shell.

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