Patent Publication Number: US-6659813-B2

Title: Male contact and method of manufacturing the same

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a male contact having a male contact section formed by bending both sides of a metal plate inward, and a method of manufacturing the same. 
     DESCRIPTION OF THE PRIOR ART 
     The contacts shown in FIG. 6 (see Japanese Patent Application Laid-Open No. H7-192793) and FIG. 7 (see Japanese Patent Application Laid-Open No. H8-162191) are known as conventional male contacts that have male contact sections formed by bending both sides of a metal plate inward. 
     Shown in FIG.  6 (A), male contact  100  comprises a male contact section  101  that contacts a mating terminal (not shown), an electrical wire termination portion  102  connected to an electrical wire (not shown), and a securing portion  103  disposed between the male contact section  101  and the electrical wire termination portion  102  that is attached to a connector housing (not shown). Shown in FIG.  6 (B), the male contact section  101  is formed by bending both sides of a stamped metal plate  104  so that joining faces  105  are positioned on an upper side in the approximate center with respect to the direction of width of the metal plate  104 . The cross-sectional shape of the male contact section  101  is a substantially oval shape in the direction of width. Upper and lower surfaces of the male contact section  101  form substantially flat contact surfaces  106 ,  107 , respectively, that contact a mating female contact (not shown). Curved sections  108  are formed on the four corners of the cross-sectional plane of the male contact section  101 . The radius of the curved sections  108  is substantially equal to the thickness of the metal plate  104 . 
     Shown in FIG.  7 (A), male contact  200  comprises a male contact section  201  that contacts a mating terminal (not shown), an electrical wire termination portion  202  connected to an electrical wire (not shown), and a securing portion  203  disposed between the male contact section  201  and electrical wire termination portion  202  that is secured to a connector housing (not shown). Shown in FIG.  7 (B), the male contact section  201  is formed by bending one side of a stamped metal plate  204  so that joining faces  205  are positioned at a side portion with respect to the direction of width of the metal plate  204 . The cross-sectional shape of the male contact section  201  is a substantially oval shape in the direction of width. Upper and lower surfaces of the male contact section  201  form substantially flat contact surfaces  206 ,  207 , respectively, that contact a mating female contact (not shown). Curved sections  208  are formed on the four corners of the cross-sectional plane of the male contact section  201 . The curved sections  208  have a radius that is greater than the thickness of the metal plate  204 . 
     Electrical connectors, such as the male contacts  100 ,  200  shown in FIGS. 6 and 7, are commonly used in industrial fields, such as the automotive field. In recent years there has been a demand for multi-pole connectors. As a result of this demand for multi-pole connectors, a need has arisen for contacts having male contact sections with a small width, for example 0.64 mm square posts. 
     When male contact sections are formed with a small width, by bending both sides of a stamped metal plate  104  or one side of a metal plate  204  in the same manner as the male contact sections  101 ,  201  of the male contacts  100 ,  200 , an insufficient area of contact with the mating female contact (not shown) arises due to the fact that the curved sections  108 ,  208  formed on the four corners of the cross-sectional plane of the male contact sections  101 ,  201  have radii substantially equal to the thicknesses of the metal plates  104 ,  204 . If a sufficient area of contact with the mating female contact (not shown) can not be obtained, the contact pressure between the contacts is unstable, resulting in unstable contact. 
     It is therefore desirable to provide a male contact having a sufficient area for contact with a mating female contact in cases where the width of the male contact section formed by bending both sides of a metal plate inward is small. It is further desirable to develop a method of manufacturing the same. 
     SUMMARY OF THE INVENTION 
     This and other objects of the present invention are solved by a contact part having an electrical wire termination portion, a metal contact part, and a securing portion disposed between the male contact section and the electrical wire termination portion. The male contact section is formed from a metal plate and has a rectangular cross-sectional shape. Curved sections are formed at corners of the cross-sectional shape that have a radius that is equal to or less than ⅓ of the thickness of the metal plate. 
     The male contact section is formed by bending both sides of the metal plate inward, and then shaping the cross-sectional shape into a substantially rectangular shape by forging so that the curved sections on the four corners of the cross-sectional plane have a radius that is equal to or less than ⅓ of the thickness of the metal plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a first side of a male contact of the present invention; 
     FIG. 2 is a perspective view of a second side of the male contact shown in FIG. 1; 
     FIG. 3 is an enlarged sectional view along line  3 — 3  of FIG. 1; 
     FIG. 4 shows a method of manufacture of the male contact section, FIG.  4 (A) shows the shapes of the dies and punches from a first step to a fourth step, and FIG.  4 (B) shows the process of deformation of the male contact section formed by the respective steps from the first step to the fourth step; 
     FIG. 5 shows the method of manufacture of the male contact section in FIG. 4, FIG.  5 (A) shows the shapes of the dies and punches from a fifth step to an eighth step, and FIG.  5 (B) shows the process of deformation of the male contact section formed by the respective steps from the fifth step to the eighth step; 
     FIG. 6 shows a first example of a conventional male contact, FIG.  6 (A) shows a perspective view, and FIG.  6 (B) shows a sectional view along line  6 B— 6 B of FIG.  6 (A); and 
     FIG. 7 shows a second example of a conventional male contact, FIG.  7 (A) shows a perspective view, and FIG.  7 (B) shows a sectional view along line  7 B— 7 B of FIG.  7 (A). 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 show a male contact  1  having a male contact section  2 , an electrical wire termination portion  3 , and a securing portion  4 . The male contact section  2  contacts a mating female contact (not shown). The electrical wire termination portion  3  is connected to an electrical wire (not shown). The securing portion  4  is secured to a connector housing (not shown) and disposed between the male contact section  2  and the electrical wire termination portion  3 . 
     The individual components of the male contact  1  will now be described in greater detail. Shown in FIGS. 1 and 2, the electrical wire termination portion  3  has a wire barrel  31  and an insulation barrel  32 . The wire barrel  31  is crimped to a core wire of the electrical wire (not shown). The insulation barrel  32  is crimped to a covering of the electrical wire (not shown). 
     Shown in FIGS. 1 and 2, the securing portion  4  has a contact lance  43 . The contact lance  43  extends upward at an inclination toward the electrical wire termination portion  3  from a portion that is bent inward from an upper edge of a first side wall  41  of the securing portion  4 . The contact lance  43  is secured to the connector housing wall (not shown) when the male contact  1  is received in a terminal accommodating hole of the connector housing (not shown). A lance protecting wall  44  extends upward from an upper edge of a second side wall  42  of the securing portion  4 . The lance protecting wall  44  prevents the electrical wire (not shown) from becoming entangled with the contact lance  43  during assembly. Shown in FIG. 2, a lower-side top plate  45  extends inward from the upper edge of the first side wall  41  and closes off a lower portion of the contact lance  43 . An upper-side top plate  46  extends inward from the upper edge of the second side wall  42  to superimpose the lower-side top plate  45 . A double locking member (not shown) engages with end surfaces of the lower-side top plate  45  and upper-side top plate  46  on the side of the electrical wire termination portion  3  when the male contact  1  is accommodated in the connector housing (not shown). The upper-side top plate  46  is installed because a sufficient margin for engagement with the double locking member can not be ensured by the lower-side top plate  45  alone. 
     FIG. 3 shows a sectional view of the male contact section  2 . The male contact section  2  is formed by bending both sides of a stamped metal plate  21  inward and then shaping the cross-sectional shape into a substantially rectangular shape by forging. The male contact  2  is formed so that the curved sections  25  on the four corners of the cross-sectional plane have a radius R that is equal to or less than ⅓ of the thickness t of the metal plate  21 . In the cross section of the male contact section  2 , the width w of the male contact section  2  is slightly greater than the thickness h, however, the cross-sectional shape is extremely close to square. As a result, the width w of the male contact section  2  is smaller than the widths of the conventional tab type male contact sections  101 ,  201  shown in FIGS. 6 and 7. The joining faces  22  on both sides of the metal plate  21  are positioned on the upper side in the approximate center with respect to the direction of width of the metal plate  21 . The upper and lower surfaces of the male contact section  2  form substantially flat contact surfaces  23 ,  24 , respectively, that contact the mating female contact (not shown). 
     A method used to manufacture the male contact section  2  will now be described in greater detail with reference to FIGS. 4 and 5. FIG. 4 illustrates the first through fourth steps used to manufacture the male contact section  2 , and FIG. 5 illustrates the fifth through eighth steps used to manufacture the male contact section  2 . The second through seventh steps represent bending processes, and the eighth step represents a forging process. 
     Shown in FIG. 4, in a first step a stamped metal plate  21  is placed on a die  50  having a flat surface. The metal plate  21  is pressed from above by a punch  51  having a plurality of projecting ribs  51   a  on a bottom surface to form a plurality of linear recessed parts  21   a  in an upper surface of the metal plate  21 . 
     In a second step, the metal plate  21  is placed on a recessed part  50   a  of a die  50 . The metal plate  21  is pressed from above by a punch  52  having a width smaller than the width of the recessed part  50   a.  The punch  52  has a tip end having a flat surface so that a pair of first bent parts  21   b  that extend upward are formed on both edges of the metal plate  21 . 
     In a third step, the metal plate  21  is placed on a recessed part  50   b  formed on a surface of a die  50 . The recessed part  50   b  has relatively gradual inclined surfaces formed on both sides. The metal plate  21  is pressed from above by a punch  53  having inclined surfaces on both sides and a tip end having a flat surface, so that the areas between the metal plate  21  and the pair of first bent parts  21   b  located on both edges of the metal plate  21  are bent slightly upward to form a pair of second bent parts  21   c.    
     In a fourth step, the metal plate  21  is placed on a recessed part  50   c  formed on a surface of a die  50 . The recessed part  50   c  has inclined surfaces formed on both sides that are somewhat steeper and deeper than the inclined surfaces of the recessed part  50   b.  The first bent parts  21   b  of the metal plate  21  are pressed from above by a punch  54  having a V-shaped recessed part  54   a  formed on a tip end, so that the pair of second bent parts  21   c  are caused to bend toward each other. 
     Shown in FIG. 5, in a fifth step the metal plate  21  is placed on a recessed part  50   d  formed on a surface of a die  50 . The recessed part  50   d  has inclined surfaces that are somewhat steeper than the inclined surfaces of the recessed part  50   c  and has the same depth as the recessed part  50   c.  The first bent parts  21   b  of the metal plate  21  are pressed from above by a punch  55  having a V-shaped recessed part  55   a  formed in a tip end so that the inclination of both side surfaces is somewhat more gradual than in the V-shaped recessed part  54   a  to bend the pair of second bent parts  21   c  so that the pair of second bent parts  21   c  are caused to bend closer toward each other. 
     In a sixth step, the metal plate  21  is placed on a recessed part  50   e  formed on a surface of a die  50 . The recessed part  50   e  has inclined surfaces formed on both sides that are somewhat steeper than the inclined surfaces of the recessed part  50   d,  and has the same depth as the recessed part  50   d . The first bent parts  21   b  of the metal plate  21  are pressed from above by a punch  56  having a V-shaped recessed part  56   a  formed on a tip end and side surfaces having an inclination somewhat more gradual than in the V-shaped recessed part  55   a,  so that the pair of second bent parts  21   c  are caused to bend closer toward each other. 
     In a seventh step, the metal plate  21  is placed on a die  50  having a flat surface. The side surfaces of the pair of second bent parts  21   c  are pressed by a punch  57  having a pair of pressing plates  57   a  that can pivot about the respective axes  57   b  until the total width wl formed by the side surfaces is substantially equal to the width w of the male contact section  2  following working. 
     In an eighth step, the metal plate  21  is placed inside a recessed part  50   f  formed on a top surface of a die  50 . The recessed part  50   f  has vertical surfaces on both sides and a width slightly greater than w 1 . The pair of first bent parts  21   b  are struck from above by a punch  58  with a tip end having a flat surface and a width slightly smaller than the width of the recessed part  50   f,  so that the male contact section  2  is formed with a substantially rectangular cross-sectional shape. 
     Shown in FIG. 3, the male contact section  2  manufactured as described herein has a substantially rectangular cross-sectional shape in which curved sections  25  formed on the four corners of the cross-sectional plane of the male contact section  2  have a radius R that is equal to or less than ⅓ of the thickness t of the metal plate  21 . Accordingly, even in cases where the width w of the male contact section  2  is small, the contact surfaces  23 ,  24  that contact the mating female contact (not shown) can be made broad, so that a sufficient area of contact with the mating female contact (not shown) can be obtained. 
     Furthermore, in the method of manufacturing the male contact of the present invention, the male contact section is formed by bending both sides of a metal plate inward, and then shaping the cross-sectional shape into a substantially rectangular shape by forging so that the curved sections on the four corners of the cross-sectional plane have a radius that is equal to or less than ⅓ of the thickness of the metal plate. Accordingly, a male contact which makes it possible to obtain a sufficient area of contact with the mating female contact can easily be manufactured even in cases where the width of the male contact section formed by bending both sides of a metal plate inward is small. 
     The foregoing illustrates some of the possibilities for practising the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.