EP0278295A1 - Miniature connector and its production process - Google Patents

Abstract

A connector has a plug and a socket. The plug is provided with at least one male contact member composed of two resilient foils in the shape of spoons. Each of these foils is mounted in a floating manner in the insulating block of the plug. The socket has a female contact member which is rigidly mounted in the insulating block. Thus, when the connector is plugged in, the contact element of the plug can align with the contact element of the socket by which it is then positioned. The connector can be executed with a distance between the contact sets of only 1.27 mm (0.05 inches). The connector is useful with surface mounting technology.

Description

The present invention relates to a miniature connector, in particular for printed circuits and to a method of manufacturing such a connector.

More particularly, the invention aims to create a connector for printed circuits provided with components called "Surface Mounted Devices" or "S.M.D." (surface mount components or SMD) and produced using a recent assembly technique. According to this technique, the electronic components placed on the printed circuit do not include connection wires requiring drilling in the circuit plate, but they are provided with flat contact pads intended for soldering. The solder material is formed by a paste made of a regular round or elliptical tin granule and it is deposited on the plate at the places where solderings must be made. After installation in the appropriate places on the circuit board, the components are then connected to the conductors of the printed circuit by heating in a steam bath brought to 200 ° C., for example. This operation melts the microbeads of tin which then link the studs of the component to the printed conductors with which the component must make contact.

Printed circuits made according to this technique can house more components per unit area than conventional circuits, in particular due to the fact that the components can be smaller. Other advantages of S.M.D. are better circuit reliability and shorter switching times.

However, to the knowledge of the Applicant, there has hitherto been no satisfactory connector whose construction allows use with circuits of the SMD type. The reasons are probably that it is necessary to considerably miniaturize the contacts while taking into account the fact that, unlike other SMD components, the connector must be subjected to mechanical stress (shock, vibration) while ensuring reliable electrical contact.

In general, one of the difficulties encountered in producing miniature multi-contact connectors lies in obtaining good alignment between the male and female contact elements, when the connectors are connected. two parts of the connector on top of each other. In fact, the smaller the dimensions, the more the inevitable manufacturing inaccuracies risk disturbing the alignment of the contact elements and increasing the relative lateral deviation of a female element and a male element. When the pitch between two adjacent contacts is only 1.27 mm, it has been found that the conventional arrangements usually provided to overcome this difficulty are no longer sufficient, since even a single connection of the connector can then cause a break in one or more contact elements. Such a break is easily explained if we consider that the contact elements have an extremely small width and thickness (resp. 1 mm and 0.1 mm in practice, for example).

The invention aims to solve this problem.

Its subject is therefore a miniature connector comprising a male plug comprising at least one contact member mounted in a first insulating block, a female socket comprising at least one contact member mounted in a second assemblable insulating block, for connecting the plug. on the socket, with the first insulating block, via said contact members, characterized in that said socket has, for each contact member of said plug, a receptacle whose wall is fixed in the socket block and formed at least partially by a portion of the contact member of the socket, and in that said contact member of the plug comprises two elastic conjugate parallel lamellae mounted floating in the block of the plug and extending partially outside this block for their engagement in said receptacle, said elastic strips being immobilized in the connector exclusively by clamping their free end portions in said receptacle tackle by virtue of antagonistic forces generated by the elasticity of the lamellae.

Because, according to these characteristics, the contact member of the plug occupies a rigid position only with respect to the second insulating block after connection of the two parts of the connector, this contact member assumes the appropriate position by absorbing any misalignment by relative to the contact member of the socket, in which the female contact member is, on the contrary, always rigidly positioned.

The invention will be better understood on reading the following description of an embodiment of the invention.

• - la figure 1 est une vue partielle en coupe du connecteur miniature suivant l'invention;
• - la figure 2 est une vue en coupe de ce même connecteur, suivant la ligne II-II de la figure 1;
• - la figure 3 représente, par une vue en perspective, deux lamelles élastiques conjuguées utilisées pour l'organe de contact de la fiche du connecteur;
• - les figures 4 et 5 sont des vues en coupe prises respective­ment suivant les lignes IV-IV et V-V de la figure 3;
• - la figure 6 est une vue en coupe du connecteur suivant l'invention dans sa configuration non-assemblée, l'échelle étant réduite par rapport à celle de la figure 1;
• - la figure 7 est une vue en coupe à la même échelle que la figure 6 du connecteur assemblé;
• - la figure 8 représente une portion de bande métallique, découpée et mise en forme, cette bande étant destinée à la mise en oeuvre du procédé de fabrication du connecteur suivant l'invention;
• - la figure 9 est une vue en coupe suivant la ligne IX-IX de la figure 8;
• - la figure 10 montre la superposition de quatre bandes du type représenté à la figure 8, cet agencement permettant d'obtenir un pas normalisé de 1,27 mm entre les contacts du connecteur;
• - les figures 11 et 12 sont des vues en coupe prises respecti­vement selon les lignes XI-XI et XII-XII de la figure 10.

In the accompanying drawings, given solely by way of example:

• - Figure 1 is a partial sectional view of the miniature connector according to the invention;
• - Figure 2 is a sectional view of the same connector, along the line II-II of Figure 1;
• - Figure 3 shows, in a perspective view, two elastic conjugate strips used for the contact member of the connector plug;
• - Figures 4 and 5 are sectional views taken respectively along lines IV-IV and VV of Figure 3;
• - Figure 6 is a sectional view of the connector according to the invention in its non-assembled configuration, the scale being reduced compared to that of Figure 1;
• - Figure 7 is a sectional view on the same scale as Figure 6 of the assembled connector;
• - Figure 8 shows a portion of metal strip, cut and shaped, this strip being intended for the implementation of the method of manufacturing the connector according to the invention;
• - Figure 9 is a sectional view along line IX-IX of Figure 8;
• - Figure 10 shows the superposition of four strips of the type shown in Figure 8, this arrangement to obtain a standardized pitch of 1.27 mm between the connector contacts;
• - Figures 11 and 12 are sectional views taken respectively along lines XI-XI and XII-XII of Figure 10.

We will first refer to Figures 1 to 7 which show the preferred construction of the miniature connector according to the invention.

The latter essentially comprises two parts, one constituting a plug 1 and the other a socket 2, and at least one set of contacts 3 composed of a male contact member 4 and a female contact member 5.

When the miniature connector comprises several sets of contacts 3, these are preferably juxtaposed so as to be able to be plugged in common. Considering FIG. 1, this juxtaposition can be carried out in the plane of the paper (solution which is not shown) or else perpendicular to the plane of the drawing (solution adopted here and visible in FIG. 2).

We will first describe the socket 2 which comprises two insulating blocks 2a and 2b made of a plastic material and assembled by ultrasound for example.

The insulating block 2a, close to the plug 1, has for each set of contacts 3 a frustoconical orifice 6 defining an axis XX and flaring in the direction of this plug 1. The block 2b, distant from the plug 1, has a cavity cylindrical 7, coaxial with the frustoconical orifice 6. The female contact member 5 is taken between the blocks 2a and 2b during the assembly of the socket 2. This contact member 5 is formed by a metal strip 8 in the form L whose longest branch 8a is clamped between blocks 2a and 2b and whose short branch 8b extends along the outer surface of block 2b. To accommodate the metal strip 8 in the socket 2, the block 2b has two grooves 9a and 9b intended to receive the branches 8a and 8b of the strip 8 respectively.

About halfway along the branch 8a, the metal strip 8 has a circular orifice 10 which is connected, on the face of this branch opposite to the block 2a, to a barrel 11 which is pushed back into the material of the strip and which extends into the cylindrical cavity 7.

The block 2a also has a peripheral clearance 12 interrupted at one of the small faces of this block by a positioning lug 13 (Figure 2).

The construction of sheet 1 is as follows.

It also comprises two blocks 1a and 1b made of insulating material and joined together by ultrasound, the joint plane of the two blocks being oriented perpendicularly to the joint plane of the blocks 2a and 2b of the socket 2. In other words, the joint plane of the plug 1 contains the axis XX, while that of the socket 2 is perpendicular to this axis.

Considering the card in its assembled configuration, it has a passage 14 whose section is of variable dimensions along the axis X-X, while having a rectangular shape over its entire length. On the side of the socket 2, the passage comprises first of all a part 15 which narrows towards the outside, this part being connected to a middle part 16 which constitutes a cavity from two opposite walls from which extend positioning pins 17. The middle part 16 is connected to an end part 18 of the passage 14.

The male contact member 4 comprises two elastic conductive strips 19a and 19b which are of identical shape and which extend in an antagonistic position relative to one another in the passage 14.

The figures show that each elastic strip has the overall shape of a spoon with a spoon 20 and a sleeve 21 folded so as to form an intermediate strip 22a and a rear strip 22b connected to each other by a recess 23.

The spoon 20 has an edge whose front part 20a is rounded and constitutes a support zone for the elastic strip and whose side parts 20b are rectilinear. These lateral parts 20b are connected by curved portions 20c to raised lateral edges 24 of the intermediate strip 22a.

In longitudinal section, that is to say as shown in FIG. 1, the bottom of the spoon 20 is inclined forward relative to the plane (perpendicular to the plane of the drawing in FIG. 1) containing the surfaces 25 through which the rear strips 22b are applied to each other when the connector is in its connected configuration. This inclination is manifested both in this configuration (FIG. 1) and in the configuration disconnected from the connector (FIG. 6), although this inclination is more pronounced in the first case than in the second. The reason is that, in FIG. 6, the strips are free and their spoons separated from one another.

On the other hand, in the connected configuration of the connector, these spoons are brought closer to one another to present a portion of electrical contact surface 26 to the female contact member. The behavior of the elastic strips 19a and 19b will be explained subsequently when the connector is connected and disconnected.

The contact surface portion 26 defined on the outer face of each spoon is located approximately at the point where the latter begins to shrink backwards by connecting to the intermediate strip 22a.

Figure 4 shows the profile of the spoon at this location, while Figure 5 shows the lamella profile at the exact point of connection of the spoon to the intermediate strip.

It should be noted that the extent of the contact surface 26 is not very well defined, because given the extremely small dimensions and thickness of each strip, the deformation which it undergoes during connection can be different from one slat to another. However, the shape of the male contact member that has just been described has proved to be extremely effective in terms of the quality of the electrical contact obtained.

A holding hole 27 is provided in the intermediate strip 22a near the recess 23. It can be seen in FIG. 1 that the diameter of this hole 27 is larger than the diameter of the section of the positioning pins 17.

It can also be noted, by examining FIG. 1, that the height of the section of the end part 18 of the passage 14 is greater than the total thickness of the two rear strips 22b superimposed of the two strips 19a and 19b when these are in place in sheet 1. Similarly, the width of the rear strip 22b of each strip 19a or 19b is less, not only to the rest of this strip, but also to the width of the section of the end portion 18 from passage 14.

As a result, when the connector is disconnected, as shown in FIG. 6, the strips 19a and 19b are completely floating in the plug 1 and they are simply held by the positioning pins 17 which extend through the holes 27.

By observing FIG. 2, it can also be seen that the width of each spoon 20 at the side edge portions 20b is less than the diameter of the hole 10 and of the barrel 11 of the female contact member.

In the disconnected configuration (Figure 6), the slats 19a and 19b are floating and therefore have a certain freedom of movement. However, the strips are formed in such a way that the spoons are elastically spaced from one another, the intermediate strips 22a coming to bear against the oblique walls of the narrowing part 15 of the passage 14.

When the plug 1 is inserted into the socket 2, the spoons 20 of the pairs of strips 19a and 19b are first brought closer to one another according to the profile of the respective frustoconical entries 6 of the socket 2. During this movement , the front portions 20a of the spoons of each pair come to bear one on the other while the intermediate strips 22a emerge from the oblique walls of the narrowing part 15 of the passage 14. This operation already implies an elastic deformation of the lamellae the rear bands 22b are more and more firmly supported one on the other. Furthermore, due to the freedom of movement available to each strip, in particular in the lateral direction, it can adapt its position to that, rigid, of the corresponding female contact member.

Continuing the insertion movement, the strips 19a and 19b are then slightly deformed in the junction zone between the spoon 20 and the handle 21, the reaction to this elastic deformation being generated at the front edges 20a of the spoons 20 and by the applying the rear bands 22b to each other.

When finally the connector reaches the connected configuration represented in FIGS. 1, 2 and 7, the elastic deformation of the strips 19a and 19b is such that they are joined to the female contact member due to the pressure exerted on it by the contact zones 26 (FIGS. 3 and 4). This results in electrical contact with an extremely low contact resistance. Furthermore, all the relative position tolerances of the contact members are fully absorbed.

The arrangement according to the invention also ensures a dissociation of the elastic functions of contact on the one hand and of shock absorption, on the other hand, the first function being provided by the spoons 20 in cooperation with the female contact member and the second by the intermediate portions 22a of the strips 19a and 19b.

The plug 1 has on its face turned towards the plug 2 a cavity 28 in which the part of this plug bordered by the clearance 6 can be positioned. The edge of the plug which delimits the cavity 28 is interrupted at 29 (FIG. 2), that is to say on one of the small faces of the block of this plug to receive the positioning lug 13 provided on the socket. Thus, connector connection errors are not possible.

It can be seen that the connector which has just been described is particularly suitable for use with the technique of "Surface Mounted Devices". By way of example, FIG. 1 shows a printed circuit board P1 on which the socket 2 is mounted by means of a connection track PC on which the small branch 8b of the metal strip 8 is welded. As already indicated above, to allow welding, the socket 2 is provided with a certain amount of a paste of tin microbeads. The plate P1 being provided with all these components, it is subjected to a steam bath at 200 ° C., which melts the tin between the contact strip 8 and the conductive track PC.

Figure 1 illustrates that the connection to a printed circuit can also be carried out by a conventional solder, which is shown here by way of example as regards the plug 3. This is connected to a printed circuit board P2 crossed by the rear strips 22b of the strips 19a and 19b of each contact assembly 3. It should be noted that this way of connecting the plug 1 to a printed circuit board somewhat limits the freedom of the strips 19a and 19b in this plug.

However, the welding being carried out at the end of the rear strips 22b, this connection does not prevent the mutual positioning of the contact members at the time of connection of the connector, as just described.

Of course, the plug 1 can also be connected to the circuit board P2 by SMD technology, for this purpose it suffices to fold the free portions of the rear portions 22b against the board P2, the corresponding contacts C of which are previously filled with paste. welding. This way of mounting the plug is illustrated in dotted lines in Figure 1.

To fix the location of the connector relative to the plates P1 and P2, positioning or spacing pins 30 may have come directly from molding with the plug 1 and the socket 2.

The material chosen for the contact elements of this connector is preferably an alloy comprising in particular nickel, copper, zinc and an additive of various other materials.

A particularly suitable material is Arcap which is a composition containing 25% nickel, 56% copper, 17% zinc and 2% of various addition metals. The contact elements are preferably gold-plated to improve their conductivity. The indicated material has the advantage of being rigorously non-magnetic, having very good corrosion resistance and having a high modulus of elasticity.

It has already been indicated above that considerable difficulties arise when it is desired to manufacture a miniature connector with a pitch between the contact assemblies as small as 1.27 mm. Of course, it would be possible to cut and form each of the contact elements separately, but such a method would require considerable labor and the connector would then have a prohibitive cost price.

It is also known in the connector manufacturing technique to cut contact elements from a strip of conductive metal so that they all extend side by side and laterally from a longitudinal zone of the strip. which is only separated from the contact elements after they have been mounted in the connector fixing blocks.

However, this method cannot be transposed directly onto contacts as small as those of the connector of the present invention, since there would remain between portions of material of the strip necessary to make two adjacent contact strips of the plug, too little material to be able to cut and shape the metal.

The invention therefore also proposes to provide a method which makes it possible to overcome this manufacturing difficulty. The principle of this process is shown in Figures 8 to 12.

FIGS. 8 and 9 show a strip 31 of conductive metal already worked to form there on the one hand positioning holes 32 and on the other hand strips 19a, 19b juxtaposed and connected to the common longitudinal area 33 of the strip by primers 34. The pitch between the lamellae is twice that which must be observed between the contact assemblies 3 of the connector. In the example described here, the pitch being 1.27 mm, the centers of the holes 32 are spaced from each other by this value. The strips 19a, 19b are kept connected to the primers 34 by rupture zones 35. The spacing between the strips is sufficient to guarantee their cutting without problems in the material of the strip, that is to say here double 1.27 mm pitch.

If, according to the method of the invention, four strips thus prepared are superimposed as shown in FIGS. 10 to 12, an assembly of the opposing strips 19a, 19b is obtained, necessary for the production of a connector with a pitch of half that of the strips of the strip shown in FIG. 8, that is to say with the pitch that one wishes to obtain.

More specifically, the strips are superimposed in pairs (strips 31a and 31b) but in such a way that their strips are offset by one step between the marking holes 32 and that the concavity of their spoon 20 is turned in the same direction. The same assembly is then prepared from the strips 31c and 31d and this assembly is superimposed upside down on the first assembly. Under these conditions, the assembly obtained comprises four bands with pairs of opposing lamellae juxtaposed at a pitch of 1.27 mm.

Such an assembly cut in length to have the desired number of contact members is then placed in a mold intended for making the insulating blocks 1a and 1b. After molding, it then suffices to break the connections in the rupture zones 35 to rid the plug of the residue from the strips 31a to 31d.

The female contact elements can be produced in the same way, using, of course, each time, only two strips from which the strips 8 will have been cut and formed.

It is obvious that many variants of the invention can be imagined. For example, it is possible to choose another form of the male contact members by giving them a constant longitudinal section over their entire width in accordance with FIG. 1. Under these conditions, it is obvious that the female contact element instead of comprising a cylindrical passage can be made in the form of one or more flat plates. However, it is essential that, whatever the variant chosen, the male contact members must always remain mounted floating in the plug 1 in order to be able to adapt when the connector is connected to variations in the dimensions of the sockets.

Claims (9)

1. Miniature connector comprising a male plug (1) comprising at least one contact member (4) mounted in a first insulating block (1a, 1b), a female socket (2) comprising at least one contact member (5) mounted in a second insulating block (2a, 2b) which can be assembled, for connecting the plug to the socket, with the first insulating block (1a, 1b), by means of said contact members (4, 5), characterized in that that said socket (2) has, for each contact member (4) of said plug, a receptacle (10, 11) whose wall is fixed in the block (2a, 2b) of the socket and formed at least partially by a portion of the contact member of the socket, and in that the contact member (4) of the plug (1) comprises two parallel conjugate elastic strips (19a, 19b) mounted floating in the block (1a, 1b) of the plug (1) and extending partially out of this block for their engagement in said receptacle (10, 11) of the socket, said elastic strips (19a, 19b) being immobilized in the connector exclusively by clamping their free end portions in said receptacle (10, 11) by virtue of antagonistic forces generated by the inherent elasticity of the strips (19a, 19b). 2. Miniature connector according to claim 1, characterized in that the wall of said receptacle (10, 11) is materialized by a contact portion formed in the contact member (5) of the socket (2) and whose section is with closed curve. 3. Miniature connector according to claim 2, characterized in that the section of said receptacle (10, 11) is circular. 4. Miniature connector according to any one of claims 1 to 3, characterized in that each strip (19a, 19b) of the contact member (4) of the plug (1) comprises a first bearing portion (20a ) at its end of engagement with the contact member (5) of the socket (2), a second bearing portion (22b) at its opposite end and, in an intermediate position, a portion of contact surface ( 26) intended to establish electrical contact with the wall of said receptacle (10, 11), the support one on the other of the bearing portions (20a and 22b) corresponding to the two strips (19a, 19b) being produced by a reaction pressure on said contact surface (26) of each lamella, generated by virtue of the elasticity thereof obtained when the connector is in the connected configuration. 5. Miniature connector according to claim 4, characterized in that each strip (19a, 19b) has roughly the shape of a spoon whose spoon (20) defines said contact surface (26), whose front edge defines said first support portion and whose handle (22) defines said second support portion (22b). 6. miniature connector according to any one of claims 1 to 5, characterized in that the strips (19a, 19b) of said plug (1) extend through a passage (14) formed in said block and in that each strip (19a, 19b) has an opening (27) in which is engaged a retaining lug (17) projecting from the wall of said passage (14), and in that the dimension of said opening exceeds the transverse dimension of said lug (17). 7. Miniature connector according to claim 6, characterized in that the dimension of said passage (14) in the direction of the width of said strips (19a, 19b) exceeds this width over the entire length of this passage (14). 8. Miniature connector according to any one of the preceding claims, characterized in that said strips (19a, 19b) are made of an alloy containing 25% nickel, 56% copper and 17% zinc. 9. A method of manufacturing a miniature connector with multiple contact assembly according to any one of claims 1 to 8, characterized in that it consists in forming in a metal strip (31a to 31d) a plurality of strips (19a , 19b) arranged side by side and extending from a continuous lateral zone (33) of this strip, said strips having in this strip a spacing equal to twice the pitch of the contact assemblies in said connector, with separate from this strip four lengths having a number of lamellae corresponding to half the number of contact assemblies that the last must present, to superimpose the four lengths thus separated by alternating reversing these strips while maintaining the lamellae on the same side, offset the slats of the first and third bands respectively second and fourth bands, to mount these superimposed lengthers in a block insulating and finally to separate the portions of strip common to the respective lamellae.

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