Abstract:
The electrical contact includes a wire crimping portion receiving an electrical wire, a cylindrical power contact portion for connection with a complementary contact. The power contact portion comprises includes a body mechanically retained on the wire crimping portion and spring legs depending from the body and to be contacted with the complementary contact. The electrical contact further includes an electrically insulating cover covering the spring legs. The cover additionally includes fool proof features to prevent incorrect assembly of the cover into passages of the housing.

Description:
FIELD OF THE INVENTION 
     The instant invention relates to electrical contacts, sets of electrical contacts, for instance for connector used in motorized vehicles, products and assemblies comprising such electrical contacts, their methods of manufacture and methods of electrical connection. 
     BACKGROUND OF THE INVENTION 
     Electrical connectors are used for connecting electrical appliances together. For example, in the automotive industry, electrically powered cars (or partly electrically powered cars, such as so-called “hybrid” cars) are emerging as an interesting alternative to the fuel-only vehicles. This requires new generations of connectors for supplying electrical motors with higher voltages than those required for appliances such as window-lifters, radio, etc. . . . ). 
     A certain class of electrical connectors usable in this context is made as an electrically insulating housing comprising three ways. In each of these ways, an electrical contact which is crimped on a cable is inserted. 
     An example of electrical contact is describes for instance in DE 1 02 11 634. This contact comprises a wire crimping portion crimped on an electrical wire and a power contact portion having a cylindrical shape for accommodating a complementary contact. The power contact portion is provided with a barrel with a plurality of contact blades elastically curved toward the central and longitudinal axis of the cylindrical power contact portion. 
     After its crimping on the wire, this contact is integrally incorporated in an insulating plastic housing comprising two separate top and bottom parts mechanically locked to one another. 
     The instant invention has notably for object to make easier the manufacturing of such a contact. 
     SUMMARY OF THE INVENTION 
     To this aim, it is provided an electrical contact according to claim  1 . 
     With these features, the electrical contact is provided with a plurality of spring legs integral with the power contact portion. This ensures direct paths for the current as well as a large surface of electrical connection between the contact and its mating contact. Further, a cover will protect the spring legs against any damage that might occur during handling, transportation or storage occurring between the manufacturing of the contact, and its insertion in the housing. Thought, the number of parts of the contact is reduced with regard to the contact disclosed in DE 1 02 11 634, making the manufacturing process easier. 
     In some embodiments, one might also use one or more of the features as defined in the dependent claims. 
     Such contacts could alternatively be used for other applications than the electrical automotive application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics and advantages of the invention will readily appear from the following description of one of its embodiments, provided as a non-limitative example, and of the accompanying drawings. 
       On the drawings: 
         FIG. 1  is a schematic representation of a manufacturing apparatus, 
         FIG. 2  is a perspective view of a product obtained at the output of the crimping portion forming station of the apparatus of  FIG. 1 , 
         FIG. 3  is another partial perspective of the product of  FIG. 2 , 
         FIG. 4   a  is a perspective view with roughly the same orientation as  FIG. 2  of a cover according to a first embodiment, 
         FIG. 4   b  is another perspective view of the cover of  FIG. 4   a,    
         FIG. 5  is a perspective view of the product output from a first assembly station of the apparatus of  FIG. 1 , 
         FIG. 6  is a perspective view of a product output from a power contact portion forming station of the apparatus of  FIG. 1 , 
         FIG. 7  is a partial sectional view of an electrical contact obtained from the apparatus of  FIG. 1 , taken along line VII-VII of  FIG. 8 , 
         FIG. 8  is a perspective view of a product output from the apparatus of  FIG. 1 , 
         FIG. 9  is an exploded view of an electrical connector assembly incorporating electrical contacts, 
         FIG. 10  is a sectional view along line X-X on  FIG. 9  of a fool-proofing body of an electrical connector of the assembly of  FIG. 9 , 
         FIG. 11   a  is a rear view of the three covers used in the connector of  FIG. 9 , 
         FIG. 11   b  is a schematic cross section of the three fool-proofing bodies of the connector of  FIG. 9 , and 
         FIG. 12  is a sectional view along line X-X on  FIG. 9 , of the partly assembled electrical connector assembly. 
     
    
    
     On the different figures, the same reference signs designate like or similar elements. 
     DETAILED DESCRIPTION 
       FIG. 1  schematically shows an apparatus  1  for the manufacture of an electrical contact. The apparatus comprises, for example, a crimping portion forming station  2 , a first assembly station  3 , a power contact portion forming station  4  and a second assembly station  5 . The crimping portion forming station  2 , the first assembly station  3  and the second assembly station  5  are for example disposed in line and adapted to perform series of operations continuously on a blank  6  of material. The blank  6  is for example provided in a shape of a continuous strip  7  to which are connected, through respective connecting portions  8 , pieces  9  to be formed. These pieces  9  are electrically conducting, for example metallic or of a metallic alloy such as a copper alloy. For example, the blank  6  as represented on  FIG. 1  was previously obtained by forming from a plane conductive thin plate. 
     The crimping portion forming station  2  needs not to be described in more details. It is sufficient to explain that it is suitable for forming, from each piece  9 , the first piece  10  as shown on  FIGS. 2 and 3 . 
     This first piece  10  comprises a wire crimping portion  11  which is directly connected to the strip  7  through the connection portion  8 , and a retention portion  12  which will be described in detail. 
     The wire crimping portion  11  comprises a partly cylindrical barrel  13  of axis X, from which extend upwardly and outwardly on  FIG. 3  two crimping wings  14 , which, at this stage of the manufactured process, are still in the uncrimped configuration. The barrel  13  and the crimping wings  14  together define a receiving space  15  for receiving the end of an electrical wire extending along a first longitudinal direction identical to the axis X. 
     The retention portion  12  comprises a flat platform or flange  60  from which a mechanical retention feature  16  projects upwardly. In the present example, it is shaped as a ring  16  extending circumferentially about a second longitudinal axis Y. In the present example, the axis Y is orthogonal to a plane defined by the first longitudinal direction X and the direction Z of extension of the strip  7 . However, the present invention could be used also for other orientations of the second longitudinal axis Y, in particular when the axis Y is parallel to the axis X. 
     The platform  60  also comprises a second mechanical retention feature  17 , which is, in the present example, performed as a tab  17  at the end of the platform  60  opposite to the end of the piece  10  connected to the strip  7 . 
     An intermediate portion  18  is provided between the wire crimping portion  11  and the retention portion  12  for connecting these two portions together. This intermediate portion  18  can for example be designed as a stepped portion for placing the ring  16  in a plane above the wire crimping portion  11 . Yet, other geometries are possible, which will depend on the configuration of the electrical connector, and the available space. 
     In the apparatus of  FIG. 1 , the product of  FIGS. 2 and 3  exits the crimping portion forming station  2  to enter a first assembly station  3 . This station also comprises a dispenser  19  (see  FIG. 1 ) of covers  20 . One embodiment of a cover is shown on  FIGS. 4   a  and  4   b . The first assembly station  3  is adapted to assemble a cover  20  to each of the first pieces  10  as obtained from the crimping portion forming station and as shown on  FIGS. 2 and 3 . 
     The covers  20  are made of an electrically insulating material such as, for example, a suitable plastic and might have been moulded to the shape shown on  FIGS. 4   a  and  4   b . Each cover  20  comprises a connecting portion  21  which is for example designed as a platform extending mainly in the reference plane P formed by the axis X and Z, and a protecting portion  22  comprising a cylindrical body  23  and a collar  24 . The top end of the cylindrical body is connected to the bottom face of the platform  21 , whereas the collar  24  is formed at the bottom end of the body  23 . The cylindrical body extends along the longitudinal axis Y and has an external wall  23   a  and an internal wall  23   b  which defines an inside space  25 . 
     The rear end of the platform  21  comprises two legs  26  symmetrical with respect to the X axis and which define, between them, an insertion opening  27 . The two legs  26  are connected together by a bridge  28  which extends over the insertion opening  27 . The insertion opening  27  comprises a first narrow space  29   a  and a broad space  29   b  closer to the axis of the cylindrical body, so that faces  30 , which face frontward, define mechanical locking features for engagement with complementary mechanical locking feature of the connector (to be explained later in relation to  FIG. 10 ). 
     The bridge  28  comprises a downward facing face  31  which defines a mechanical locking feature with the first piece  10  as will be explained below in relation to  FIG. 7 . 
     The lateral sides  32  of the bridge  28  are provided with specific geometrical features to provide a fool-proofing feature for engagement with a complementary fool-proofing feature of the connector, as will be explained later in relation to  FIGS. 10 to 11   b.    
     In the first assembly station  3 , the cover  20  which has just been described is assembled with the first piece  10  which was described before, by any suitable way. For example, as shown on  FIG. 5 , the cover is slid along the axis X toward the first piece  10 . The tab  17  of the retention portion  12  of the first piece  10  is inserted in the space  29   a  and  29   b  until the top face of the tab  17  is in contact with the downward facing face  31  of the bridge  28  (see also  FIG. 7 ). The top face of the platform  21  is thus below the bottom face of the platform  60  of the first piece  10 . 
     Referring back to  FIG. 1 , a second blank  106  is introduced into the power contact portion forming station  4  of the apparatus  1 . The second blank  106  is, for example, of similar design as the blank  6 , and comprises a strip  107  extending along a longitudinal direction Z and to which pieces  109  are connected through connecting portions  108 . However, other embodiments are possible. The power contact portion forming station  4  is suitable to form any of the pieces  109  to a power contact portion  33  such as shown on  FIG. 6 . Such a power contact portion is for example obtained by forming (stamping) a flat piece  109  and then rolling it to the desired geometry, or by any other suitable way. 
     As shown on  FIG. 6 , the power contact portion  33  is a cylinder of circular cross-section and comprises a body  34  from which extend a plurality of (for example 8) spring legs  35  sensibly along the longitudinal axis Y. The legs  35  extend sensibly downward from the body  34  and inward toward a point of contraflexure  36  from which they are flared outward to their tip. The internal face at the point of contraflexure forms a protrusion which projects inside an internal space  61  for receiving a complementary electrical contact therein. This complementary electrical contact is preferably of diameter greater than the internal diameter of the power contact portion  33  at the level of the protrusions so that the legs will be resiliently biased in contact with this complementary electrical contact upon its insertion in the internal space. 
     In the present example where the power contact portion  33  is manufactured from rolling a metal blank, a gap  37  may exist between the two longitudinal edges which are brought close to each other during the rolling operation. This gap  37  may be closed, for example, by welding, or by any other suitable means. 
     Referring back to  FIG. 1 , the product, shown on  FIG. 5 , comprising a strip of first pieces  10  of metal carrying a respective cover, is moved from the first assembly station  3  to the second assembly station  5 . Simultaneously, the power contact portion  33  is moved from the power contact portion forming station  4  to the second assembly station  5  to be inserted along the axis Y, from the top, through the ring  16  and the cover  20 . The external surface of the body  34  biases in electrical contact with the inner face of the ring  16  for electrical communication between these two pieces. The spring legs  35  are totally enclosed in the cover  20 . The body  34  can be welded, if necessary, to the ring  16 , or only retained by friction, or any other means. It should be noted that, after the power contact portion  33  has been inserted, it is no longer possible to remove the cover  20  from the electrical contact by sliding along direction X. 
       FIG. 8  shows the product which is output from the second assembly station  5  shown schematically on  FIG. 1 . This product comprises a longitudinal strip  7  to which are connected a plurality of electrical contacts  38 . For example, the electrical contacts  38  are all identical. In another example, these electrical contacts  38  have different covers having different colours and/or fool-proofing features (see below  FIGS. 11   a  and  11   b  for more details about this). The product shown on  FIG. 8  can be provided to a third party for cable assembly and terminal insertion in connectors. In alternative, the individual electrical contacts  38  could be separated from the strip  7  before being provided to a cable assembler or a harness maker. As an alternative, the electrical contacts are not necessarily manufactured as two separate conductive pieces. An integral piece comprising a power contact portion and a wire crimping portion might be used. 
     An example of a suitable connector for use with the electrical contacts as described above is shown in exploded partial view on  FIG. 9 .  FIG. 9  shows a first electrical connector  39  and a second complementary electrical connector  139  to be mated with. 
     The first electrical connector  39  is for example made as a dielectric housing  40  defining a plurality of pathways  41   a ,  41   b ,  41   c  which are electrically isolated from one another and extend with a right angle (between axis X and axis Y). Namely, a first end of these openings is provided on a front face of the connector  39 , while a second end thereof is provided on its bottom face (not visible on  FIG. 9 ), facing the second connector  139 . 
     As shown on the left side of  FIG. 9 , three electrical contacts  38   a ,  38   b ,  38   c  are provided which are manufactured according to the above mentioned process. These three terminals differ from one another by each having a different cover  20   a ,  20   b ,  20   c . The wire crimping portion  11  of each electrical contact is crimped on a respective electrical wire  42  for placing the wire in electrical communication with the electrical contact  38 . This can, for example, be performed by folding the crimping wings of the electrical contact on the wire, with a suitable tool comprising a stamping element and an anvil. An insulating joint  43  is slid along the sheath of each wire  42  to the position of  FIG. 9  and a grid  44  is placed by inserting the wire  42  through the respective openings  45  of the grid. The grid has locks  46  for engagement with complementary locks  47  of the first connector  39  to lock the grid onto the first connector  39 . In this locked position, the joints  43  are circumferentially pressed by internal walls  48  of the first connector  39 , and longitudinally pressed between the grid  44  and respective fool-proofing bodies  49  of the respective pathway  41 . This will be described in relation to  FIG. 10 . 
     The electrical contact  38  is mechanically retained in the housing  40  of the first connector by mechanical engagement of the hook  54  with the faces  30  of the cover (see  FIG. 4   a ). 
     Referring back to  FIG. 9 , the second electrical connector  139  may for example comprise three cylindrical chimneys  50 , cylindrical of circular cross-section of diameter greater than the outer diameter of the covers  20 . An electrical contact  51  is provided for each respective chimney  50 . These electrical contacts  51  may, for example, comprise a first end  51   a  which extends in the chimney  50 , and an opposite second end  51   b  for connection to an electrical appliance. 
       FIG. 10  shows a sectional view through the pathway  41   b . Only the fool-proofing body  49   b  delimiting this pathway is depicted. As explained above, this body  49  has an aperture  52  on the one hand, for receiving the electrical contact  38 , and another aperture  53  in its bottom face for receiving the electrical contact  51  of the complementary connector. A locking tool  54  is provided on the back face of the body  49   b , for example as a hook extending from this back face toward the aperture  52  and having a catching portion  55  born by a resilient arm  56 . 
     The body  49   b  has a fool-proofing relief  57  in the top left corner of its profile, which is provided with a given geometry. The body  49   b  is for example made from moulded plastic and may for example be provided with a pigment of a first colour. 
     It is locked to the housing  40  of the first electrical connector through any suitable means, such as spring lances  58  which engage with complementary features  59  ( FIG. 12 ) of the internal faces of the housing  40 . 
     As shown on  FIG. 11   a  and  11   b , each of the covers  20  has a different fool proofing feature  32  with a specific geometry. Further, although this is not visible on  FIG. 11   a , each of the covers may incorporate a respective pigment so that they all have different colours. As shown on  FIG. 11   b , the fool-proofing bodies  49  all have a different fool proofing geometry  57 . Further, they all include a different pigment, which provides different colours. For example, the colour of one of the bodies  49  is associated to, preferably is the same as, the colour of a respective cover. Further, the geometries  32  and  57  are chosen so that, among the three covers of  FIG. 11   a , only one can enter a respective body  49 , and is prevented to enter the other bodies. Further, each body can receive only one of the covers. Preferably, the cover which is allowed to be inserted in a respective box is provided with a colour associated to the colour of that box. 
     The connector assembly is shown on  FIG. 12  with the complementary connector  139  partly assembled. As shown, each electrical contact  38  is a right-angled contact in that its two connection axes X and Y are perpendicular to one another. The cover  20  is guided into a respective chimney  50  and the complementary electrical contact  51  is placed in electrical contact with the power contact portion  33  of the electrical contact  38 .