Patent Publication Number: US-8979602-B2

Title: Electrical male terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application under 35 U.S.C. §371 of PCT Application Number PCT/IB2011/002077 having an international filing date of Aug. 5, 2011, which designated the United States, which PCT application claimed the benefit of PCT Application Number PCT/IB2010/002447, filed Aug. 20, 2010, the entire disclosure of each of which are hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to electrical male terminals and methods of manufacturing such electrical male terminals. 
     BACKGROUND OF THE INVENTION 
     An electrical male connector comprises usually an insulator housing accommodating one or more assemblies of a male terminal mating adapted to mate with a complementary electrical female terminal. 
     For automotive applications in particular, connectors are submitted to vibrations, sometimes amplified by vibration resonances with the electrical cables linked to such connectors. It is of paramount importance to maintain a high quality of the electrical contact between terminal surfaces belonging to the female terminal and terminal surfaces belonging to the male terminal during the whole life of the vehicle. 
     For such terminals, it is also a requirement to reduce the size of such male/female terminal assemblies without reducing the electrical connection performances. 
     Usually, for automotive applications, an electrical male terminal comprises a wire connecting portion adapted to be crimped or soldered or attached by any adapted means to an electrical wire. Such a male terminal usually also comprise a positioning portion adapted to locate properly and lock the electrical male terminal into a surrounding housing. Further, such a male terminal comprises a mating portion adapted to electrically contact a corresponding mating female terminal. 
     Such electrical male terminal may be obtained from a metal sheet which is deformed to obtain the desired form and targeted dimensions. 
     A goal of the invention is to provide an electrical male terminal improving the current capability, while complying with the geometric requirements of the positioning portion. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a preferred embodiment, the invention provides an electrical male terminal which is designed to be inserted in a housing. It comprises a positioning portion with locking means adapted to interact with the housing. 
     It is formed from a single metal plate. It extends substantially along a longitudinal axis. This terminal comprises a positioning portion and a mating portion. 
     The mating portion is defined as the portion of the male terminal which will be in electrical contact during the mating process of a male and female terminal. 
     The mating portion has two substantially parallel contact surfaces adapted to be in electrical contact with respectively two surfaces of the female terminal during this mating process. 
     The mating portion has a mating portion seam between two folded portions of the metal plate which is not located on the contact surfaces. 
     Such a feature allows improving the current capability, while complying with the geometric requirements of the positioning portion. Indeed, due to the folding process, a joint, sometimes also called a “seam”, creates a groove or another kind of surface irregularity between two regions or portions of the folded metal sheet. Such seam may create bad contacts that are detrimental to the electrical connexion over time. The invention removes the seam from the contact surface while keeping the possibility to meet the geometric requirements of the positioning portion. 
     According to another aspect of the invention, the invention is directed to a method of manufacturing such a electrical male terminals. 
     Further, according to another aspect of the invention, the invention is directed to an assembly along a metal strip of several electrical male terminals as above defined. 
     In some other embodiments, one might also use one or more of the features as defined in dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       Other characteristics and advantages of the invention will readily appear from the following description of some of its embodiments, provided as a non-limitative example, and of the accompanying drawings. 
       On the drawings: 
         FIG. 1  is a perspective view of an electrical male terminal according to an embodiment the invention, 
         FIGS. 2A and 2B  show cross sections of the terminal of  FIG. 1 , with respect to lines IIA and IIB of  FIG. 1 , 
         FIG. 3  is a perspective view of a unitary stamped metal plate adapted to form the terminal of  FIG. 1 , 
         FIG. 4A-4C  are diagrams illustrating the method of manufacturing the terminal of  FIG. 1 , according to different sections respectively with respect to lines IVA, IVB, IVC of  FIGS. 1 and 3 , 
         FIG. 5  is a diagram similar to  FIG. 4A , illustrating a variant of the embodiment of  FIG. 1 , 
         FIG. 6  shows an assembly of several terminals as the one of  FIG. 1 , and 
         FIG. 7  is a partial cross-section of an assembly of the male terminal of  FIG. 1  and a corresponding female terminal. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows an electrical male terminal  10  extending generally along a longitudinal axis (X). This terminal comprises a wire crimping portion  52  adapted to receive an electrical wire  6  (shown in phantom line) which can be crimped within the wire crimping portion  52  as well known in the art thus not described in details here. The wire crimping portion  52  exhibits first legs  54  adapted to be crimped around the metal core of the wire  6  and second legs  55  adapted to be crimped around the insulation layer of the wire  6 . 
     The terminal also comprises a positioning portion  51 , extending from the wire crimping portion  52  along the longitudinal axis (X). The positioning portion  51  is linked to the wire crimping portion  52  by an attachment junction  56 . The wire crimping portion  52  has a cross-section perpendicular to the longitudinal axis (X) which has a generally rectangular shape with a top face  21 , a bottom face  22 , parallel and opposed to the top face  21 , and side faces  23 , 24  (visible on  FIG. 4C ). The side faces  23 ,  24  are perpendicular to and adjacent to the top and bottom faces ( 21 ,  22 ). The positioning portion  51  further comprises locking means, for instance a locking window  9  open in the top face  21 . The positioning portion  51  is adapted to position and lock the electrical male terminal  10  properly in a surrounding housing (not shown). 
     The terminal further comprises a mating portion  1 , adapted to electrically mate and connect with a corresponding female terminal  4  (shown partially in  FIG. 7 ). The mating portion  1  extends along the longitudinal axis (X) and comprises a top contact surface  31  parallel to the top face  21  of the positioning portion  51 , a bottom contact surface  32  opposed to the top surface  31 , and side portions ( 14 ,  15 ), adjacent to the top and bottom surfaces ( 31 ,  32 ). The mating portion  1  has a cross section, perpendicular to the longitudinal axis (X), defining a male terminal width W 1  and a male terminal thickness E 1  (cf.  FIG. 2A ). 
     The terminal further comprises a transition portion  2 , extending between the positioning portion  51  and the mating portion  1  along the longitudinal axis (X). The transition portion  2  has a first end adjacent to a respective end of the positioning portion  51  with a tapered section  25 . The tapered section  25  corresponds to a matching cross section the surface of which decreases from the first end towards a portion of the transition portion  2  having a cross-section substantially equal to the cross-section of the mating portion  1 . 
     Referring now to  FIG. 1 ,  FIG. 2A ,  FIG. 2B  and  FIG. 7 , the mating portion  1  comprises a first seamless strip  11  and a second seamless strip  12 . Both of the first and second seamless strips  11 ,  12  have a width W 1  corresponding to the mating portion width W 1 . They form surfaces which are respectively adapted to bear on and to contact a first and second female terminal surfaces  41 ,  42  of the female terminal  4 . The second seamless strip  12  is opposed to the first seamless strip  11 . Consequently, the mating portion  1  is interposed between first and second parallel female terminal surfaces  41 ,  42 . 
     In the present embodiment, the mating portion  1  further comprises a third metal strip  13  interposed between the first and second seamless strips ( 11 ,  12 ). The width of the third metal strip  13  is smaller than the width of the first seamless strip W 1  and it corresponds to W 1  minus the thickness of the first seamless strip  11 . 
     In this embodiment, the first, second and third seamless strips  11 ,  12 ,  13  are substantially flat, and have a substantially constant and identical thickness (about E 1 / 3  in the illustrated example). 
     In this embodiment the mating portion  1  is made of a metal sheet  20  (copper, aluminum, metal alloy, etc.). This metal sheet  20  is folded and exhibits a seam or joint ( 17 ,  17 A,  17 B,  17 C) after folding. This seam  17  comprises a mating portion seam  17 A, located in the mating portion  1 , which is parallel to the longitudinal axis (X), and located on one of the side portions ( 14 ,  15 ). 
     The seam  17  also comprises a positioning portion seam  17 C located on the top face  21  of the positioning portion  51 . 
     The seam  17  further comprises transition portion seam  17 B extending from the mating portion seam  17 A to the a positioning portion seam  17 C. 
     In this embodiment, the transition portion seam  17 B comprises a transverse portion  17 T which is perpendicular to the longitudinal axis (X), the transverse portion  17 T having two ends, a first end adjacent to the mating portion seam  17 A, and a second end adjacent to a quarter of circle, the quarter of circle joining the transverse portion  17 T to the rest of the following transition portion seam  17 B which is located at the median longitudinal line of the top surface  31 , as also clearly illustrated on  FIG. 2B . 
     As illustrated in particular in  FIG. 2B , a portion  13 B of the third metal strip  13  extends in the transition portion  2  up to the tapered section  25 , under the two adjacent halves  18 ,  19  located on top on the third metal strip  13   
     As illustrated in particular in  FIG. 2A , the second seamless strip  12  is linked to the first seamless strip  11  by a first curved side portion  14  having a C-shaped cross section, and the third seamless strip  13  is linked to the second seamless strip  12  by a second curved side portion  15  having a C-shaped cross section. 
     Therefore, the mating portion  1  and the transition portion  2 , excepted the tapered section  25 , comprise a three-layer configuration with the three seamless strips  11 ,  12 ,  13  which are superimposed. The three-layer configuration of the mating portion  1  provides it with a good mechanical strength and in particular a good robustness against flexion and torsion forces. This further provides the male terminal  10  with a good electrical current capability. 
     The surfaces  31 ,  32  are free from any seam or joint which is beneficial to improve the terminal surface with the corresponding contact surfaces of the female terminal  4 . 
     Instead of a locking window  9  as mentioned above the positioning portion  51  may have any other locking means, for example a locking leg protruding from a top face  21 , a side face  23 ,  24 , or a bottom face  22 . Such a locking means is adapted to engage a complementary locking means in the surrounding housing (not shown) to retain the male terminal  10  in an appropriate position. 
     The positioning portion seam  17 C intersects the locking window  9 . Advantageously, it corresponds to the median longitudinal line of the top face  21 . Therefore, the positioning portion  51  has a symmetry plane parallel to a vertical XZ plane running through the longitudinal axis (X). 
     According to another aspect of the invention, as illustrated on  FIG. 6 , it is provided a product  3  comprising a linking strip  5  extending along the transverse direction (Y) and a plurality of male terminals  10  as defined above, each one of which being mechanically attached to the linking strip  5 . 
     According to another aspect of the invention, a method of manufacturing is provided in order to produce a male terminal  10  as described above. 
     Usually the male terminals  10  are manufactured by batches, i.e. a large plurality of electrical male terminals  10  being attached to the already mentioned linking strip  5 . 
     Starting with a bare metal sheet having the desired thickness, a stamping operation is used to output a plurality of flat stamped metal sheets  20  as the one illustrated in  FIG. 3 . The plurality of identical stamped metal sheets  20  are attached along a linking strip  5  at predetermined positions. 
     The forming process comprises a succession of forming operations, which will be explained hereafter with the help of  FIGS. 3 ,  4 A,  4 B and  4 C. 
     The unitary stamped metal sheet  20  has a flat surface and comprises a first portion  61  adapted to form the wire crimping portion  52 , a second portion  62  adapted to form the positioning portion  51 , a third portion  63  adapted to form the transition portion  2 , and a fourth portion  64  adapted to form the mating portion  1 . 
     From another point of view, the unitary stamped metal sheet  20  comprises a first member  71  extending along the longitudinal axis (X), adapted to form the third metal strip  13 , a second member  72  also extending along the longitudinal axis (X), and adapted to form the second seamless strip  12  and one half  18  of the top surface of the transition portion  2  and one side  24  of the positioning portion  51 , a third member  73  also extending along the longitudinal axis (X), and adapted to form the second half  19  of the top surface of the transition portion  2  and the other side  23  of the positioning portion  51 , and a fourth member  74  adapted to form, in the mating portion  1 , the second seamless strip  12  and, in positioning portion  51 , the bottom face  22 . 
     The forming process comprises for example as illustrated on  FIGS. 4A-4C , at least the following operations:
         (a) folding the first member  71  substantially with a 180-degree angle around a first folding axis (F 1 ) parallel to the longitudinal axis, the first member  71  forming the third metal strip  13  (see the top sketch of  FIG. 4A ),   (b) folding the second member  72 , in the mating portion  1 , with a substantially 180-degree angle around a second folding axis (F 2 ) parallel to the longitudinal axis, the second member  72  carrying the first member  71 ; this result in a three-layer configuration in the mating portion  1  as illustrated in the middle sketch of  FIG. 4A ,   (c) folding the second member  72 , in the positioning portion  51 , with a 90-degree angle around the second folding axis (F 2 ),   (d) folding the third member  73 , in the positioning portion  51 , with a 90-degree angle around a third folding axis (F 3 ) parallel to the longitudinal axis as illustrated in the bottom sketch of  FIG. 4B .       

     Further forming step(s) are necessary to obtain the desired form, in particular for the positioning portion  51 . As illustrated in  FIG. 4C , additional folding steps allow folding both halves  210 ,  220  toward the horizontal plane XY, to result in forming the top face  21  of the positioning portion  51 . 
     When all forming steps are performed, it is provided, as illustrated in  FIG. 6 , a product  3  comprising a linking strip  5  and a plurality of electrical male terminals  10  as described above. 
     Further, one or more male terminals  10  can be detached from the product  3  by cutting or breaking the attachment bridge  57  (cf.  FIGS. 1 and 6 ). Further, a resulting individual male terminal  10  can be crimped on a wire  6  as mentioned above. 
     The seam  17  may be located elsewhere within the top face  21 , for example on a side portion. The seam  17  may also comprise different curved portions. The locking window  9  may be located elsewhere, for example in the side faces  23 ,  24 , and of course there may be several locking windows. 
       FIG. 7  shows an assembly of electrical terminals comprising a male terminal  10  as described above, and a corresponding female terminal  4  (only partially shown in  FIG. 7 ). The female terminal  4  comprises a first and a second elastic members  43 ,  44  having respectively a first and a second female terminal surfaces  41 ,  42  adapted to bear respectively on the top and bottom surfaces  31 ,  32  of the mating portion  1 . 
     The tip  100  of the mating portion  1  comprises a bevel shape comprising a first bevel section  110  belonging to the first seamless strip  11 , a second bevel section  120  belonging to the second seamless strip  12  and a third bevel section  130  belonging to the third seamless strip  13 . 
     The absence of seam  17  on the surfaces  31 , 32 , 41 , 42  improves the quality of the electrical contact, and suppresses the risk of mechanical damage during mating or unmating, thereby ensuring an increased lifetime of the terminals. 
     In a variant of the above embodiment, illustrated in  FIG. 5 , the first member  28  is slightly narrower than the first member  71  of the preferred embodiment, while all the other aspects are similar to the preferred embodiment. Therefore, the third metal strip  13  is reduced to a folded side rib  29  that defines the thickness E 1  of the mating portion  1 . 
     Furthermore, an additional spacer  63  can be inserted between first and second seamless strips  11 ,  12 , as shown in  FIG. 5 . This additional spacer  63  can be a tooling extension that will not remain the terminal, or can be an additional part remaining in the male terminal  10 . In this variant, it should be noted that the thickness of the seamless strips  11 ,  12  can be different from E 1 / 3 : the thickness of the additional spacer  63  and or the side rib  29  can be greater or smaller than E 1 / 3 . The thickness of the metal sheet  20  can be for example reduced, regardless of the target thickness E 1  for the mating portion  1 .