FR2591809A1 - Socket contact member for a multi-contact self-stripping connector for flat cables and process for manufacturing such a connector - Google Patents

Abstract

a. Socket contact member for a self-stripping connector. b. It is characterised in that the socket contact part 24 includes two branches 25, 26 having contact surfaces 27, 28 over at least a part of the main faces in order to interact with the main contact surfaces of the pin contact member, at least one of the branches 25, 26 being moved away from the other branch by elastically pressing against the contact surfaces of the pin contact member. c. The invention relates to multi-contact connectors.

Description

"Female contact member for a multi-contact insulation displacement connector for flat cable and method of manufacturing such a connector".

 The present invention relates to a female contact member for a self-stripping connector with multiple contacts, member cut from a sheet of conductive metal and comprising, on the one hand, a fork-shaped part whose branches are intended to pierce the material synthetic of the ribbon cable with several conductors to overlap a conductor and make electrical contact therewith and, on the other hand, a female contact part intended to cooperate with the male contact member, homologous, of a connector to male contacts.

 According to French Patent No. 73 40 294, an electrical connector is known for a flat cable with several conductors. This connector consists of two parts, one being a base, the other the cover joined to each other by elastic hooking lugs.

 These two parts are joined with the interposition of the flat cable.

 The base includes housings distributed along a geometry suitable for receiving contact members; the latter consist of a metal part comprising a fork-shaped part with two teeth whose ends are pointed and sharp and a contact part.

 The fork is intended to pierce the cable to the right of the conductor with whom contact must be made. This fork cuts the cable insulation and meets the conductor by establishing electrical contact.

 The various contact members are placed in the receptacles of the base then the cable is positioned above the base and the cover having holes corresponding to those of the base is pressed on the cable and the base. so that the forks' branches penetrate the flat cable.

 The length of the fork legs being greater than the thickness of the cable to ensure good contact, the projecting ends of the fork teeth come into the housings of the cover.

 The other part of the contact members protrudes from the base and forms the rods of the male contacts.

 This prior technique does not address the problem of female contact parts but especially the principle of the contact fork.

 The question of female contacts has been addressed in US Patent No. 3,820,058. In this prior art, the female contact member, consisting of a part cut from a strip, comprises a fork-shaped part of the above type , as well as a female contact part. The female contact part is constituted by two bars integral with a strip folded over the fork-shaped part.

The two contact tabs of this female contact part apply to the contact rod of the male part. The production of such a female contact member is relatively complex and costly. In addition, the member is not located in a plane, which requires a mold of very complex shape with also very complex positioning of the contact members for overmolding the connector or part of it.

 A connector is also known according to US Patent No. 3,912,854. In fact, the technique described in this patent relates to the installation of the self-stripping forks of the female contacts. This document is included in the present description by way of reference describing this process.

 This technique is also explicitly described in French patent FR-1 567 642 which relates to multiple connectors with insulation-displacement contacts for flat cables, in particular, the installation of such a connector in two parts on a flat cable with multiple conductors.

 The main difficulty of the contact members for connectors of the type of those mentioned above is the positioning of the contact members in the housings of the base. Indeed, these contact members, of very small dimensions, must be placed in the housings of the base, generally in two rows, the axis of each fork being offset by -l / 4 of pitch relative to the axis of the contact part.

 During their installation, the contact members remain attached by a weak connecting strip, which can be achieved when stamping the members in the metal strip. Then detach the connecting strip from the contacts. These are inserted into the cable and carry out the self-stripping at the same time as the mold is closed. After this installation, the base is injected into the mold, which is thus overmolded on the contact members and on the cable.

 One such known technique uses a flat contact member of the type mentioned in the preamble.

The storytelling organ also consists of a female contact part constituted by two branches in the shape of
U whose ends of the branches are rounded in shape to form the contact surfaces for the male contact member.

 As these are contact members which must be flat to allow simplified positioning in the mold used to overmold the base on the cable, the contact surfaces of these female contact members are located on the branches.

 However, these cut surfaces are irregular while the main faces of these contact members, which correspond to the laminated faces, are not used for contact.

 In addition, due to this shape and the arrangement of the contact members in rows in the base, the contact surfaces are supported on the secondary surfaces of the contact plugs constituting the male members. Indeed, male contact member in general a rod of square section, terminated by a pyramid point. This male contact member has two main surfaces and two auxiliary surfaces. The main surfaces correspond to the laminated faces of the blank used to make these rods while the auxiliary surfaces are not laminated and are therefore irregular.

 The cooperation of the contact surfaces of the female part and the contact surfaces of the male part results in a contact whose contact resistance is high and which is outside the standards required by many industries.

 The present invention aims to remedy these drawbacks and proposes to create a self-stripping female contact member for multiple contact connector, which is of a particularly simple embodiment, of an easy and simple implementation, by particularly for the overmolding of the corresponding part of the connector and which ensures excellent contact, satisfying the requirements and, in particular, the various standards relating to contact resistance.

 To this end, the invention relates to a contact member of the above type, characterized in that the female contact part comprises two branches having contact surfaces on at least part of their main faces to cooperate with the main surfaces contact of the male contact member, homologous, at least one of the branches being separated from the other so that the two contact surfaces are separated so as to allow the introduction of the rod of the contact member male and the elastic bearing of the contact surfaces of this female contact member, against the main contact surfaces of the male contact member.

 This member can be cut flat and keep this shape during molding, which facilitates the automatic positioning of the contact members in the mold. As after molding, one or both branches of the connector are spaced from each other by a sufficient distance for the insertion of the plug, the contact surfaces are formed by the main surfaces of the part , i.e. laminated surfaces. In addition, this form of contact member makes it possible to apply the contact surfaces against the main faces of the contact plugs. There is therefore, for these contact members, a double improvement in contact, making these contact members conform to current standards.

 The contact members are particularly simple to manufacture and to assemble.

 The contact members have, thanks to their branches, an excellent elasticity which is preserved over time. and is not very sensitive to fatigue. The pressure exerted on the contact plug is regular and practically symmetrical.

 In addition, the curvature of the branches is made at the base of the branch so that this camber does not influence the quality of the contact surface.

 According to another characteristic, the two branches are L-shaped whose large parts have different lengths and whose small parts constitute the contact surfaces.

 This embodiment is particularly simple.

 According to another characteristic, one of the branches has two U-shaped legs, the middle part of which constitutes the contact surface and the other I-shaped branch is placed between the two legs of the first branch.

 This characteristic is particularly advantageous for having good pressure on the contact surfaces, and this without causing a larger bulk of the part since one of the branches fits into the other.

 According to another characteristic, the two branches are offset asymmetrically relative to the plane of the contact member, one of the branches remaining in the plane and the other being offset relative thereto.

 According to a characteristic of the invention, the two branches of the female contact part are offset substantially by the same distance relative to the plane of the contact member before deformation.

 According to another characteristic, the contact surfaces of the branches of the female contact part are constituted by elements of a very conductive metal such as gold, of an encrusted coating, made of such a metal.

 It is particularly advantageous to be able not only to benefit from the quality of the condition of the main surfaces but also from the excellent conductivity of a noble metal without it being necessary for all the faces of the part to be covered with a such expensive metal or without requiring complicated operation.

 Finally, the invention also relates to a method of manufacturing an insulation displacement connector for a flat cable with multiple conductors, method according to which, after fixing in the overmolding mold of the female contact members and placing of the flat cable, then racking in of the corresponding parts of the female contact members, synthetic material is injected to overmold the contactor base, a process characterized in that the contact surfaces are produced on the main faces of the branches of the female contact members, cut to flat, and after overmolding of the base, at least one of the branches is curved to separate one of the contact surfaces from the other to allow the insertion of the male plugs.

 This process is particularly simple to implement since it does not require any particular mold and the only additional tool required is a bending tool} which is of particularly simple construction and implementation, does not not slowing the molding yield since the bending is done outside the mold and in masked time.

The present invention will be described in more detail with the aid of the accompanying drawings in which
- Figure 1 is a perspective view, schematic, very simplified of a female contact member for self-stripping connector, according to the prior art, and a conductor overlapped by this contact member.

 - Figure 2 is a schematic view of the general arrangement of the elements of a connector with respect to a ribbon cable.

 - Figure 3 is a detail view on an enlarged scale corresponding to Figure 2 respecting the orientation of this figure.

 - Figure 4 is a plan view of a first embodiment of a female contact member according to the invention.

FIG. 5 is a plan view of a second embodiment of a female contact member according to the invention,
- Figure 6 is a side view of a female contact member according to the invention, and the connector base, molded onto the contact member and a cable conductor.

 - Figure 7 is a sectional view corresponding to Figure 6 but showing the female contact member after shaping of its branches.

 - Figure 8 shows in sectional view a connector with two rows of female contact members and a connector with two rows of body contact members.

 - Figure 9 is a view similar to that of Figure 7 but in which the female contact members have undergone a symmetrical bending with respect to their plane.

 - Figures lOA, lOB show two stages of manufacture of the end of the branches of a female contact member.

 - Figure lOC shows another step of manufacturing the conductive surfaces of the branches of a female contact member according to the invention, resulting in the same structure as that shown in Figure lOB.

 FIG. 1 shows a known female contact member 1 for a self-stripping connector with multiple contacts. This member cut from a sheet of conductive metal has a part 2 in the form of a fork which overlaps a conductor 3 of a ribbon cable after the points 4 of the member 2 in the form of a fork have pierced and torn the plastic insulator constituting the coating part of the conductors of the ribbon cable (not shown); thus this fork-shaped part 2 overlaps the conductive member 3 by releasing the latter so that there is electrical contact between the conductor 3 and the member 1.

 The second part 5 of the contact member is the female contact part comprising two U-shaped arms 6, 7, the ends of which have domed parts 8, 9 for the contact surfaces 10, 11 intended to be applied against the male contact member. These contact surfaces 10, 11 are formed on the edge of the part. However, these surfaces 10, 11 and more generally the edge of the part, constitute auxiliary surfaces whose finish is relatively poor, unlike the main faces which correspond to the faces of the metal sheet from which this member has been cut. 1. The main faces are in fact the laminated faces, perfectly flat and have no deformation or roughness.

 The female contact members 1 such as that shown in FIG. 1, are cut into strips and remain connected to one another for their placement in the molds used to mold the base of synthetic material securing the female contact members and the conductors of the ribbon cable.

 FIG. 2 shows a ribbon cable 12 with several conductors as well as the arrangement of the female connector and the location of the plugs 13 of the male connector.

The conductors of the cable 12 are shown schematically and by dashed lines. In reality, the number of cable conductors is much greater.
It should also be noted that the female contact members are distributed in several rows, here 2 in number, with a staggered offset since the space available would not be sufficient to juxtapose the contact members. The arrangement of the plugs of the male contact members corresponds to those of the female members.

 According to FIG. 2, the branches 6, 7 of the female contact members are applied against the lateral faces of the male contact members 13. The female contact members are aligned in the two rows of locations since these members are held by a part of the mold used for overmolding the base on the contact members and on the cable.

 FIG. 3 shows in an enlarged manner the relative arrangement of the female and male contact members without the orientation of FIG. 3 having been changed with respect to the orientation adopted in FIG. 2.

 The male contact member 13 has two main faces 14, 15 and two auxiliary faces 16, 17. This figure also shows the two branches 6, 7 of the female contact member as well as the contact surfaces 10, 11 of these branches.

 By examining both Figures 2 and 3, we note that the surfaces 16, 17 of the male conductive members 13 are the auxiliary surfaces which are turned towards each other for the different male contact members.

 The other surfaces 14, 15 or main surfaces are the laminated surfaces of the strip from which the plugs constituting the male contact members have been cut, the lateral surfaces 16, 17 being the cut surfaces.

 The main surfaces are very regular surfaces presenting a perfect state to establish a good contact. On the other hand, the auxiliary surfaces 16, 17 have a relatively irregular state and are unsuitable for contact. Resistance measures have confirmed this situation.

 However, according to the prior art and the known female member shown in FIG. 1, the electrical contact between the two branches of this contact member and the corresponding male plug, takes place on the one hand, on the contact surfaces 10 , 11 corresponding to the wafer or to the thickness of the female contact member 1 and, on the other hand, due to the necessary arrangement of the female contact members relative to the ply of multiple conductors, the contact surfaces 10, 11 can only come into contact with the auxiliary surfaces 16, 17 of each cut male contact member.

 There is therefore a double accentuation of the bad contact, which results in a significant resistance of passage which is outside the standards of practically all the user countries.

 In FIG. 4, a female contact member 20 according to the invention, cut from a sheet or strip, consists of a fork portion 21 whose branches 22, 23 pointed with preferably sharp edges serve to place and cut the plastic material of the cable to establish contact with the corresponding conductor.

 The second part 24 of this contact member is the female contact part intended to cooperate with the main faces of a male contact plug.

 This part 24 consists of two branches 25, 26 each terminated by a contact surface 27, 28. These surfaces are produced on one or the other of the main faces of the contact member, that is to say tell the laminated surfaces of the sheet from which this piece was cut. According to this first embodiment, the branches 25, 26 are not of the same length and the ends of the branches are turned towards each other so that the contact surfaces 27, 28 are aligned along the corresponding axis AA to the position of the plug.

 FIG. 5 shows another variant of female contact member 30 for a self-stripping connector. This member also comprises a part 31 in the form of a fork and a female contact part 32, with two branches 33, 34. The branch 34 is in the form of an I or tongue and the branch 33 is in the form of an inverted U surrounding the branch 34. This branch 33 has two legs 35, 36.

 The contact surface 37 is at the end of the branch 34 while the contact surface 38 of the branch 33 is the junction of the two legs 35, 36.

 Figures 6 and 7 show the two main phases of manufacturing a connector using a female contact member according to the invention, whether it is the embodiment according to Figure 4 or that of Figure 5.

 FIG. 6 shows the arrangement of a row of contact members 40 and the base 41 molded onto the cable 42. In this position, at the outlet of the mold, the members 40 are still flat, the branches carrying the surfaces of contact 43, 44 are in the same plane.

 Figure 7 shows the result of the second main phase of manufacturing a connector. The branch carrying the contact surface 44 has been arched relative to the branch of the contact surface 43, so that the two surfaces 43, 44 are sufficiently spaced apart to allow the insertion of the plug, while exerting a sufficient pressure. The axis B-B of the male plug has been represented in this figure. Although the deformation is limited to a single branch asymmetrically deformed, it is also possible to arch the two branches and in particular symmetrically.

It should be noted that the arching is done on the branch part outside the contact surface
Figures 8 and 9 show two female connectors 50, 60 comprising a base 51, 61 molded onto the cable 70, a connector cover 52, 62 and a portion 53, 63 of the male connector.

 In the case of FIG. 6, the female contact members 54 are bent asymmetrically with respect to the plugs 55 whereas in FIG. 9, the bend is symmetrical for the branches of the contact members 64 with respect to the plugs 65.

 FIGS. 10A, B, C show stages for manufacturing the contact surfaces of the female contact members according to the invention.

 According to FIG. 10A, the two faces 80, 81 of a metal sheet 82 or of a ribbon are partially covered with a highly conductive coating, for example gold. This coating is produced only at the location of the contact surfaces of the members which are cut from this sheet or strip.

 There is thus obtained, after cutting, the part 83 shown in FIG. 10B, which is a section through the parts of the branches carrying the contact surfaces 84, 85, 86, 87 of which only the surfaces 84, 87 or 85, 86 will be used after bending.

 FIG. 10C shows a variant according to which the contact surfaces consist of incrustations 91, 92, 93, 94 made of noble metal and then the members are cut out as above.

 The female contact members for insulation displacement connectors, according to the invention, are implemented in a particularly advantageous manner since they can be fixed in molds for overmolding the cable to produce the base of the connector. After this molding, according to the invention, one or both of the branches of these contact members are arched, which can then be applied perfectly against the main faces of the plugs of the male contacts.

Claims (6)

 10) Female contact member for a self-stripping connector with multiple contacts, member cut from a sheet of conductive metal and comprising, on the one hand, a fork-shaped part whose branches are intended to pierce the synthetic material of the cable in sheet with several conductors, to overlap a conductor and make electrical contact therewith and, on the other hand, a female contact part intended to cooperate with the male contact member, homologous to a connector with male contacts , characterized in that the female contact part (24, 30) has two branches (25, 26, 34, 35, 36) having contact surfaces (27, 28, 37, 38) on at least part of their main faces to cooperate with the main contact surfaces (14, 15) of the male contact member (13), homologous, at least one of the branches (25, 26, 34, 35,  36) being separated from the other so that the two contact surfaces are separated so as to allow the introduction of the rod (13) of the male contact member and the elastic bearing of the contact surfaces (27, 26, 37, 38) of this female contact member, against the main contact surfaces (14, 15) of the male contact member.  20) Contact member according to claim 1, characterized in that the two branches (25, 26) are L-shaped whose large parts have different lengths and whose small parts constitute the contact surfaces (27, 28) .  30) Contact member according to claim 1, characterized in that one of the branches (35, 36) is with two U-shaped legs, the middle part (38) constituting the contact surface and the other branch ( 34) in the shape of an I, is placed between the two legs (35, 36) of the first branch.  40) Contact member according to any one of claims 1 to 3, characterized in that the two branches are offset asymmetrically with respect to the plane of the contact member (54), one of the branches remaining in the plane and the other being offset from it.  5) Contact member according to any one of claims 1 to 3, characterized in that the two branches of the female contact part are offset substantially by the same distance from the plane of the contact member (64) before deformation .  6) Contact member according to claim 1, characterized in that the contact surfaces of the branches of the female contact part (80, 81, 84-87, 91-94) are constituted by elements of a very conductive metal , like gold, of an encrusted coating. made of such a metal.  70) Method for manufacturing a self-stripping connector for a flat cable with multiple conductors, method according to which, after fixing in the overmolding mold of the female contact barley and placing of flat cable, then plugging in of the corresponding parts of the female contact members, synthetic material is injected to overmold the base of the contactor, process characterized in that the contact surfaces are produced on the main faces of the branches of the female contact members, cut flat, and after overmolding of the base, at least one of the arms is arched to separate one of the contact surfaces from the other to allow the insertion of the male plugs.