Connector with contact

A connector (1) having a contact (2) for being crimped by one side thereof onto a conductor (3) of a cable (4) is provided on the other side with an elastic tongue (7) which can contact a printed circuit introduced in such connector. The elastic tongue is allowed a wide displacement, due to the structure of the arm (6) which joins the elastic tongue to the insulation displacement device (8-10) held by a blade (5) of the contact (2).

The invention relates to a connector having a contact. More particularly,
 it finds use in the field of connections, of telephony and computer
 applications, particularly of the RJ45 type. In prior art, in order to
 electrically connect two elements, for instance a cable and a printed
 circuit, two complementary connectors are used, each comprising a contact
 complementary to the other. These two contacts are to be connected
 together. Each contact is connected by a first end to one of the two
 elements, and has, at the other end, a rigid surface to be applied to the
 one of the complementary contact. The invention provides a single contact,
 comprised in a single connector, which may be directly connected to the
 two elements to be electrically connected. The interest of the invention
 lies in that a lower number of components is needed to connect two
 elements together.
 In prior art, a first contact is connected to a first element. This first
 element is, for instance, a cable. The first contact is comprised in a
 first connector. This first contact includes an insulation displacement
 device, to allow electric connection thereof to the conductors of the
 cable. It also has a free edge for contacting a second contact. The edge
 of the first contact is a flat and rigid surface. The second contact is
 connected to a second element. This second element is, for instance, the
 metal plating of a printed circuit. In this case, the second contact is
 fastened to this second element by welding. The second contact is
 comprised in a second connector, complementary to the first connector. It
 also has accessible flat and rigid surfaces, which may contact the edge of
 the first contact.
 Prior art connectors involve a first dimensional problem. In fact, prior
 art connectors are composed of many components: at least two complementary
 connectors and two contacts being allowed to be connected together. The
 provision of two connectors implies a construction which is incompatible
 with the miniaturization of the assembly.
 The number of components of the assembly implicitly requires a number of
 actions for assembling such connection device and for making the
 connection. In fact, contacts have to be inserted into a connector,
 connectors have to be connected to the elements and finally, connectors
 have to be connected together.
 Also, a prior art RJ45 connector cannot allow to reversibly connect two
 elements like a cable and a printed circuit. In fact, the printed circuit
 is flat and rigid. It has no cavity allowing to accommodate the RJ45
 connector which also has flat and rigid contacts. Further, even when the
 printed circuit has a device for fastening a RJ45 connector, the quality
 of electric connections between two flat contacts is not assured. In fact,
 if a gap or clearance exists between the contact of the connector and the
 metal plating of the printed circuit, which is not foreseen by the
 fastening device, the connection will not be effected. Such a connector
 does not allow direct connections to printed circuits whose flatness is
 imperfect. If a jaw is provided as a fastening device, carried by the
 connector for accommodating the printed circuit, the thickness variation
 of printed circuits is such that electric contact is not effectively
 ensured.
 It is an object of the invention to obviate the above drawbacks by
 providing a single connector comprising a contact which may be
 electrically connected by its ends to two elements. The contact
 particularly allows a first end to be connected to a cable thanks to an
 insulation displacement device for insulator removal. At a second end, the
 contact has an elastic tongue which allows to force said tongue against a
 rigid and flat element, e.g. a printed circuit. The elastic tongue is a
 device which allows to ensure a reliable electric connection to a rigid
 element. This second rigid and flat element is thereby connected to the
 cable.
 Also, the contact in accordance with the invention has a joint for
 connecting these two ends. This joint allows, on the one hand, to dispose
 the elastic tongue in the connector, in a location wherein it will be free
 and capable to contact a printed circuit. Further, this joint allows a
 wider displacement of the elastic tongue with respect to the contact body.
 The contact thus conceived may be adapted to contact several different
 types of rigid and flat elements, other than printed circuits, or printed
 circuits with different thicknesses.
 A RJ45 plug, wherein this contact is inserted, is designed to fit into a
 receptacle. Such receptacle has a printed circuit projecting out of one of
 its apertures. Here, the printed circuit is held perpendicular to the
 plane formed by the aperture. The tongue of this contact is forced against
 the metal plating of the printed circuit upon introduction of the printed
 circuit in the aperture. The curve followed by the tongue ensures electric
 connection to the metal plating, while admitting a slight variability of
 the circuit position, as well as a slight variation of its thickness.
 Therefore, the invention addresses a connector having a contact which
 comprises a body provided at one end with a rigid blade holding an
 insulation displacement means for connection to a conductor of a cable,
 characterized in that it has an elastic tongue at a second end, and an arm
 joining the rigid blade to the elastic tongue.

A connector 1 in accordance with the invention, as shown in FIG. 3,
 comprises a contact 2 mounted onto the conductors 3 of a cable 4. The
 contact 2, as shown in FIG. 1, has a rigid blade 5 joined to an elastic
 tongue 7 by an arm 6. The contact 2 is flat and preferably cut out flat
 into a metal sheet, which allows to effectively control its elasticity,
 hence the pressure force on the printed circuit. In one example, the
 contact is 0.25 mm thick. The blade 5 is placed at a first end of the
 contact 2. The blade 5 has a first tooth 8 and a second tooth 9. The teeth
 8 and 9 are separated by a recess 10. The teeth 8 and 9 rise up on the
 blade 5, in the plane of the contact 2. They rise up parallel to an axis
 11. The blade 5 has an overall parallelepiped shape. The recess 10
 accommodates a conductor 3 of the cable 4, whereas the teeth 8 and 9
 penetrate such conductor 3 and divide its wires. The teeth 8 and 9 and the
 blade 5 are more resistant than the conductors 3. In fact, when pressure
 is applied on an edge 12 of the contact 2, the blade 5 and the teeth 8 and
 9 remain intact, and penetrate a sheath of the conductors 3. The contact 2
 is preferably made from a phosphor bronze alloy, obtained by die forming.
 The teeth 8 and 9 are sharp-edged so as to contact the (invisible) core of
 the conductor 3. The edge 12 is perpendicular to the plane formed by the
 contact 2. In FIG. 3, the contact 2 is inserted into the connector 1 by
 applying a force, parallel to the plane thereof, on the edge 12. This
 force is applied, for instance, by a crimping clamp. The assembly is
 conducted in two steps. First, the contact is mounted in a narrow housing
 for the body of the connector 1, in a preloaded position. In this
 position, a space for introducing the conductors 3 remains open. In order
 to keep the contact in this preloaded state, the blade has deformations
 over its plane, i.e. one or more bosses 13 resting against the walls of
 the narrow housing. Then, the contacts 2 are sunk from their preloaded
 position into the conductors 3 of the cable 4, previously introduced into
 a cavity 14 of the connector 1. Hence, the connector 1 is electrically
 connected to the cable 4.
 The arm 6, as shown in FIG. 1, extends from the blade 5. A first segment 15
 of this arm 6 extends perpendicular to the axis 11 of the blade 5. In FIG.
 1, the arm 6 forms a bend 16 delimiting a second segment 17 of the arm 6.
 The segment 17 extends parallel to the axis 11. The segment 17 has a
 variable width. It particularly has a narrower part 18. Such narrower part
 18 is situated after a wider part of the segment 17. The segment 17
 borders one side of the blade 5. In one example, the segment 17 is longer
 than the blade 5 topped by the teeth 8 and 9.
 The segment 17 forms, at an end 19 opposite to the bend 16, a second bend
 20. The bend 20 is such that a part 21 of the arm 6 folds along and
 parallel to, the end 19 of the segment 17. This part 21 is short and
 defines a loop, immediately after the bend 20, by a third bend 22. This
 bend 22 delimits a second part 23 of the arm 6. This part 23 extends
 perpendicular to the axis 11. The bend 22 covers an angle of about
 90.degree.. The part 23 has a length defined to be smaller than the depth
 of a cavity 24, as shown in FIG. 3, for housing the arm 6. The part 23 is
 delimited by a fourth bend 25, covering about 90.degree., opposite to the
 bend 22. The part 23 determines a last segment 26 of the arm 6. The
 segment 26 is thus substantially parallel to the axis 11. In short, the
 arm 6 is composed of segments 15, 17, 21, 23 and 26, and also comprises
 bends 16, 20, 22 and 25. The multiply bent structure provides an increased
 stiffness, hence a controlled elasticity of the arm 6, while admitting a
 wide displacement thereof.
 The elastic tongue 7 is joined to the segment 26 of the arm 6 by a last
 bend 27. The elastic tongue 7 has a curved shape. The curve of the elastic
 tongue 7 forms a contact bend. This contact bend 28 is oriented parallel
 to the axis 11. The elastic tongue 7 is shorter than the portion 23. Also,
 the elastic tongue 7 extends below the portion 23.
 The elastic tongue schematically has a v shape, the vertex of the v being
 the contact bend 28. Here, the vertex of the v is oriented opposite to the
 tips formed by the teeth 8 and 9. The contact bend 28 is designed to
 contact a contact of a connector which is complementary thereto, in the
 broad sense. This complementary connector may be a receptacle adapted to
 the connector 1. The considerable displacement of the flexible tongue 7
 allows to fill the clearance which can exist between these two connectors.
 When a printed circuit, as shown in FIG. 3, is inserted into the cavity 24,
 the metal plating of the printed circuit can contact the contact bend 28
 of the elastic tongue 7. The cavity 24 has a height 29, which enables the
 introduction of a printed circuit having a thickness below said height 29.
 The cavity 24 has a lower edge for accommodating a printed circuit. Prior
 to the introduction of the printed circuit, the contact bend 28 protrudes
 inside the cavity 24. The height 29 reduced by the contact bend 28, which
 protrudes inside the cavity 24, is shorter than the typical thickness of a
 printed circuit. As a variant, the contact bend 28 is engaged in a groove
 of the lower edge 30 through which the contact 2 has been inserted. In the
 latter case, the segment 26 is slanted to allow the tongue 7 to be lifted
 upon introduction of the printed circuit.
 When a printed circuit is inserted into the cavity 24, it forces the
 contact bend 28, hence the assembly consisting of the elastic tongue 7 and
 of the arm 6 upwards, to find the space to accommodate its thickness
 inside the cavity 24. The introduction of a printed circuit generates a
 stress oriented in one direction 31, which is the same as the direction
 wherein the teeth 8 and 9 extend parallel to the axis 11. The elastic
 tongue 7 and the arm 6 are deformed by this stress, resulting in an
 elevation 32 of the contact bend 28. The elevation 32 transmitted to the
 different bends 27, 25, 22 and 20 results in an overall rotation of the
 arm 6. The contact 2 as shown in FIG. 1 provides a wider displacement and
 an increased stiffness, because the oriented stress 31 is transmitted to
 all the bends formed by this contact 2.
 Since the contact is cut out flat, the contact bend 28 is sharp enough to
 penetrate a tin-plated contact area of the printed circuit, thereby
 generating a high-quality tight electric connection.
 In a first variant of the contact 2, as shown in FIG. 2a, the arm 6 only
 has the segment 15 and the bend 27. Here, the arm 6 has no intermediate
 bends between the blade 5 and the elastic tongue 7. The arm 6 therefore
 consists of the segment 15, extending from the blade 5 perpendicular to
 the axis 11. In this case, the arm 6 is straight, and the bend 27 forms a
 90.degree. lower angle, so that the tongue 7 folds over the arm 6. The arm
 6 also has, in the median part thereof, a narrower part 18.
 A further characteristic of this variant is that it provides a contact bend
 28 oriented in the same direction as the teeth 8 and 9. So, the connector
 1 has a contact bend 28 whose displacement will occur in the lower part
 30. Hence, the contact bend 28 can contact the metal plating of the
 printed circuit oriented towards the lower face 30. However, the contact 2
 may be introduced into a part opposite to the lower part 30. This variant
 allows a poor flexibility, the admitted flexibility of the contact 2 lying
 in the bend 27 and in the contact bend 28. The displacement admitted by
 this contact 2 is narrower than the displacement 32 admitted by the
 contact as shown in FIG. 1. The contact 2 as shown in FIG. 2a tolerates a
 smaller difference between thicknesses of the different printed circuits,
 which may be introduced into the cavity 24. However, this structure is
 less fragile and more compact. Typically, the latter type of contact is
 connected to the conductors of the cable upon molding of the body of the
 connector 1. Nevertheless, this contact may also be inserted into the
 connector 1. In this case, it is inserted by one front face 33
 perpendicular to the lower part 30, introduced on the side of the cavity
 24. The contact 2 is then kept inside the cavity 24 by means of a mortise
 34 formed in the blade 5. This mortise 34 is fitted with a tenon held by
 the connector body. The mortise 34 is situated opposite to the point
 whereat the segment 15 is inserted into the blade 5. Bosses like 13 may be
 provided to keep the contact inside the cavity 24.
 A further variant of the contact 2 is shown in FIG. 2b. In this variant,
 the contact 2 has an arm 6 which is slightly different from the arm 6 as
 shown in FIG. 1. Here, the arm 6 of the contact 2 does not have the bends
 22 and 25. Further, it does not have the segments 23 and 26. The bend 20
 forms a right angle, so that the segment 21 which is defined from the bend
 20 is approximately perpendicular to the axis 11. This arm 6 is composed
 of the segments 15, 17 and 21, and comprises the bends 16, 20 and 27. The
 bend 27 delimits the arm 6 of the elastic tongue 7. The bend 27 is
 oriented so that the elastic tongue 7 folds below the segment 21 of the
 arm 6. Here, the bend 28 held by the elastic tongue 7 is oriented in the
 same direction as in FIG. 1. However, the displacement of the elastic
 tongue 7 is narrower than the one obtained with the contact as shown in
 FIG. 1, because the structure of the arm 6 is less flexible. Particularly,
 the bend 27 readily abuts against the ceiling of the cavity 24. The latter
 variant is less flexible. In fact, the arm 6 has a lower number of bends
 than the arm 6 as shown in FIG. 1. Like in FIG. 2a, this variant of the
 contact 2 has a lower tolerance with respect to the intrinsic variation
 which may exist between the thicknesses of printed circuits. The pressure
 force on the printed circuit is increased. This variant is preferably
 suitable for applications wherein a considerable insertion force is
 required, and the number of couplings has to be small.
 The connector 1, as shown in FIG. 3, is of the RJ45 type, hence it has an
 elastic lever 35 above the cavity 24. This elastic lever 35 may be lowered
 to allow the introduction of the connector 1 inside an aperture of a
 receptacle containing a printed circuit to be connected to said connector.
 The metal plating to be connected to the connector can be placed on an
 upper or lower face of the printed circuit. According to the type of
 contacts as shown in FIGS. 1, 2a or 2b, the connection will be effected on
 one of the two faces of the printed circuit. Therefore, there may be
 provided connectors 1 comprising the different kinds of contacts 2,
 particularly in the case of double-faced printed circuits. The contacts 2
 are each inserted into an individual narrow cell of the connector 1.