Patent Publication Number: US-6336829-B2

Title: Electrical connector free from soldering contamination

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electrical connector to be mounted on a printed circuit board (PCB). 
     2. Field of the Invention 
     Japanese patent application Kokai No. 6-310197 discloses an electrical connector of this type. As shown in FIG. 7, a contact terminal  40  has a fixing section  41 , a contact section  42  extending downwardly from the fixing section  41 , and a terminal lead  43  extending laterally from the fixing section  41 . It is mounted over the side walls  44  and  45  of a plug cavity  47  of a connector body  46  such that the contact sections  42  are exposed within the plug cavity while the fixing sections  41  and the terminal leads  43  are outside of the plug cavity  47 . 
     In order to prevent movement of the contact sections  42 , the terminal leads  43  and fixing sections  41  are placed on the outside of the side walls  44  and  45  while the contact sections  42  are placed on the insides of the side walls  44  and  45  so that capillary effects are produced to pull the flux from the mounting area to the contact sections  42 , making unstable contact conditions. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide an electrical connector able to prevent the flux and solder from climbing from the mounting area on a PCB, thereby providing stable contact conditions. 
     According to the invention there is provided an electrical connector comprising an elongated connector body having a plug cavity for receiving a mating connector; a plurality of terminal mounting spaces provided within the plug cavity with a predetermined pitch in a longitudinal direction of the connector body; a plurality of contact terminals each having a fixing section, a terminal lead extending from one end of the fixing section, a U-shaped section extending from the other end of the fixing section, and a contact section extending from the U-shaped section; the fixing sections being mounted in the terminal mounting spaces such that the terminal leads projecting from the connector body and the contact sections facing a center of the plug cavity; and a device for preventing the contact sections from moving toward the fixing sections. 
     The terminal length between the contact section and the fixing section is large, the contact section is connected to the fixing section via the U-shaped section, the device for preventing the contact section from moving toward the fixing section and keeping it from the side wall to avoid the capillary effects thereby preventing the flux and solder from climbing from the mounting area on the PCB. 
     According to an embodiment of the invention there is provided an electrical connector comprising a plurality of partition walls to form the terminal mounting spaces with the pitch in the longitudinal direction; and the device comprises protrusions which are provided on sides of the partition walls and enter gaps between the contact sections and the fixing sections of the contact terminals. 
     The protrusions enter the gaps between the contact sections and the fixing sections to prevent the contact sections from moving toward the fixing sections and keep the contact sections from the side walls, thereby preventing the capillary effects and the flux and solder from climbing from the mounting area on the PCB, thus providing a stable contact. 
     According to another embodiment of the invention, the device comprises an inward edge extending laterally from the contact section toward the fixing section. 
     The inward edge prevents the contact section from moving toward the fixing section and keeping the contact section from the side wall, thereby avoiding the capillary effects to prevent the flux and solder from climbing from the mounting area on the PCB, providing a stable contact. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a top plan view of a receptacle connector according to an embodiment of the invention; 
     FIG. 1B is a side elevational view of the receptacle connector; 
     FIG. 2 is a sectional view taken along line  2 — 2  of FIG. 1B; 
     FIG. 3 is a sectional view taken along line  3 — 3  of FIG. 1B; 
     FIG. 4 is a perspective view of contact terminals mounted in the receptacle connector; 
     FIG. 5 is an elevational view of the contact terminal viewed from an arrow C of FIG. 4; 
     FIG. 6 is a perspective view of contact terminals according to another embodiment of the invention; and 
     FIG. 7 is a sectional view of a conventional receptacle connector. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the invention will now be described with reference to the accompanying drawings. 
     First Embodiment 
     An electrical connector according to the first embodiment of the invention is shown in FIGS. 1A and 1B, and  2 . 
     A receptacle connector  20  comprises an elongated connector body  1  with a mating connector plug cavity  2  having terminal mounting spaces  9  and a plurality of contact terminals  12  mounted on the terminal mounting spaces  9 . 
     The plug cavity  2  extends downwardly from the top face of and along the length of the connector body  1  and has left and right side walls  3  and  4 , a bottom wall  5 , and front and rear walls  6  and  7 . 
     A plurality of partition walls  8  extend inwardly from the left and right side walls  3  and  4  with a predetermined pitch along the length of the connector body  1  to form the terminal mounting spaces  9 . A plurality of terminal apertures  10  extends through the bottom wall  5  of the terminal mounting spaces  9  and the lower ends of the left and right side walls  3  and  4 . A pair of protrusions  11  extend vertically on the front and back sides  8   b  and  8   a  of each partition wall  8  but they are spaced from the printed circuit board  19 . 
     As shown in FIGS. 3 and 4, the contact terminal  12  has a fixing or press-fit section  13 , a terminal lead  14  extending laterally from the press-fit section  13 , a linking or U-shaped section  15  extending upwardly and then downwardly from the press-fit section  13 , and a contact section  16  extending downwardly from the linking section  15  and is parallel to the press-fit section  13  with a gap  17 . The width L 1  of the contact section  16  is greater than the width L 2  of the linking section  15 . The width of each extended side  16 A is (L 1 −L 2 )/2. 
     The contact terminal  12  is mounted in the terminal mounting space  9  through the terminal aperture  10  by inserting the press-fit section  13  into the terminal mounting space between the partition walls  8  such that the terminal lead  14  projects from the terminal aperture  10  and the contact section  16  faces the center of the plug cavity  2 . The protrusions  11  on the front and rear sides  8   a  and  8   b  of the partition wall  8  are inserted in the gap  17  between the contact section  16  and the press-fit section  13 . The extended sides  16 A of the contact section  16  abut against the protrusions  11  to prevent the contact section  16  from moving toward the press-fit section  13 . 
     The receptacle connector  20  is mounted on a printed circuit board  19  by inserting a positioning pin  18  into a positioning hole  19 A such that the terminal leads  14  of the respective contact terminals  12  are brought into contact with solder cream on the contact pattern of the PCB  19  and the terminal leads  14  are soldered by reflow to the contact pattern. 
     By plugging a mating plug connector into the receptacle connector  20 , the contact terminals of the plug connector are brought into contact with the respective contact terminals  12  of the receptacle connector  20 . 
     The contact sections  16  of the contact terminals  12  are pressed by the contact sections of the plug connector toward the press-fit sections  13  but unable to move toward the press-fit sections  13  because the extended sides  16 A abut against the protrusions  11 . 
     Since the press-fit section  13  and the contact section  16  of the contact terminal  12  are not exposed from the plug cavity  2  owing to the left and right side walls  3  and  4 , the adjacent contact terminals mounted on the PCB  19  are not short-circuited by a conductive foreign object, such as dirt and dust, attached to the outer side faces. 
     Since the terminal length from the press-fit section  13  to the contact section  16  of the contact terminal  12  is large and the contact section  16  is connected to the press-fit section via the U-shaped section  15  and since the protrusions  11  of the partition wall  8  enter the gaps  17  between the contact sections  16  and the press-fit sections  13  of the contact terminals  12  to prevent the contact sections  16  from moving toward the press-fit sections  13  and the contact sections  16  are spaced from the terminal leads  14 , it is possible to avoid the capillary effects, thereby preventing climbing of flux and solder from the mounting area of the PCB  19 , thus providing a stable contact. 
     The width of the contact section  16  may be equal to that of the U-shaped section  15 . In this case, the protrusions  11  may be provided only between the contact section  16  and the press-fit section  13  to prevent climbing of the flux and solder. It is preferred that the protrusions  11  are spaced from the PCB  19  to prevent climbing of the flux and solder from the mounting area. 
     The extended sides  16 A increase the contact area of the contact section  16  so that even if the plug connector is plugged in the receptacle connector  20  offset in the longitudinal direction of the connector body  1 , a reliable contact is obtained. 
     The protrusions  11  may be replaced by only one protrusion provided on either front face  8   a  or rear face  8   b  of the partition wall  8 . As shown in FIG. 4, the terminal lead  14  may extend straight from the press-fit section  13  and inserted into and soldered to a through-hole of the PCB  19 . 
     Second Embodiment 
     The second embodiment of the invention is shown in FIG.  6 . 
     The receptacle connector  20  comprises a connector body  1 - 1  with a plug cavity  2  having terminal mounting spaces  9  and a plurality of contact terminals  12 - 1 . 
     The connector body  1 - 1  is identical with the connector body  1  except for omission of the protrusions  11 . The contact terminal  12 - 1  is identical with the contact terminal  12  except that it is provided with an inward edge  21 . 
     The contact terminals  12 - 1  are inserted into the terminal mounting spaces of the contact body  1 - 1  through terminal apertures  10  by press-fitting the press-fit sections into the terminal mounting spaces  9  between partition walls  8  such that the terminal leads  14  project from the terminal apertures  10  and the contact sections  16  face the center of the plug cavity  2 . 
     The receptacle connector  20  is mounted on the PCB  10  by inserting a positioning pin  18  into the positioning hole  19 A of the PCB  19  such that the terminal leads  14  of the contact terminals  12 - 1  are brought into contact with solder cream on the contact pattern of the PCB and the terminal leads  14  are soldered by reflow to the contact pattern. 
     By plugging a mating plug connector into the receptacle connector  20 , it is possible to bring the contact terminals of the plug connector into contact with the contact terminals  12 - 1  of the receptacle connector  20 . 
     The contact sections  16  of the contact terminals  12 - 1  are pressed by the contact terminals of the plug connector toward the press-fit sections  13  but hardly able to move toward the press-fit sections because the inward edges  21  abut against the press-fit sections  13 . 
     Since the press-fit section  13  and the contact section  16  of the contact terminal  12  are not exposed from the plug cavity  2 , the adjacent contact terminals mounted on the PCB  19  are not short-circuited by a conductive foreign object, such as dirt and dust, attached to the outside of the side walls. 
     Since the length between the press-fit section  13  and the contact section  16  is large, the contact section is provided with the inward edge  21  to prevent movement of the contact section  16  toward the press-fit section  16 , and the contact section is spaced from the side walls  3  and  4 , it is possible to avoid the capillary effects, thereby preventing climbing of the flux and solder from the mounting area on the PCB  19 , thus providing a stable contact. 
     The extended sides  16 A increase the contact area of the contact section  16  so that even if the plug connector is plugged into the receptacle connector offset in the longitudinal direction of the connector body  1 , there is provided a reliable contact condition. 
     As has been described above, the electrical connector according to the invention has a long terminal length between the fixing or press-fit section and the contact section, with a linking or U-shape section linking the contact section and the press-fit section, and a stopper device for preventing the contact section from moving toward the press-fit section and the terminal lead to thereby prevent the capillary effects and climbing of the flux and solder from the mounting area on the PCB, thus providing a stable contact. 
     Since the protrusions of the partition wall enter the gap between the contact section and the press-fit section to prevent movement of the contact section toward the press-fit section and keep the contact section from the side walls to prevent the capillary effects and climbing of the flux and solder from the mounting area on the PCB, a stable contact is obtained. 
     Since the inward edge is provided for the contact section to prevent movement of the contact section toward the press-fit section and keep the contact section from the side walls, thereby preventing the capillary effects and climbing of the flux and solder from the mounting area on the PCB, a stable contact is obtained.