Patent Publication Number: US-8123542-B2

Title: Contact and connector including the contact

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a contact and a connector including the same. 
     2. Description of the Related Art 
     Conventionally, there has been disclosed a conductive terminal (contact) including a contact portion, a mounting portion, a body portion connecting the contact portion and the mounting portion, and a holding portion disposed between the contact portion and the mounting portion (see e.g. Japanese PCT application translation Publication No. 2005-525684). 
     The conductive terminal is inserted into a housing from a rear side of the housing, whereby the holding portion of the conductive terminal is held in the housing. 
     The holding portion of the conductive terminal extends in the inserting direction of the conductive terminal. Further, the holding portion has an opening and a slot extending in the inserting direction of the conductive terminal, for adjusting the impedance of the conductive terminal. 
     The connector including the above-described conductive terminal suffers from the problem that the holding portion of the conductive terminal is formed with the opening and the slot, as described above, and hence the holding force of the holding portion for holding the conductive terminal in the housing is weak. Therefore, there is a fear that the conductive terminal moves from a predetermined position in the housing or comes off the housing due to some cause. Further, the holding portion forms a stub, which makes it difficult to obtain desired impedance. In designing a terminal such that a desired impedance is obtained, it is troublesome to adjust the impedance. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of these circumstances, and an object thereof is to provide a contact which is capable of facilitating the adjustment of impedance and ensuring a high holding force when the contact is held in a housing, and a connector including the contact. 
     To attain the above object, in a first aspect of the present invention, there is provided a contact comprising a contact portion that is capable of being brought into contact with one object to be connected, a press-fitting portion that is press-fitted into a housing, a connecting portion connected to said press-fitting portion, said connecting portion extending from a rear end of said press-fitting portion in an inserting direction of said press-fitting portion, toward a rear side in the inserting direction, a spring portion connected to said contact portion for pressing said contact portion against the one object to be connected, said spring portion having said press-fitting portion connected thereto, and being bent in a manner folded back from said rear end of said press-fitting portion in the inserting direction toward a front side in the inserting direction, and a terminal portion connected to said connecting portion, for being connected to the other object to be connected. 
     With the arrangement of the contact according to the present invention, as described above, the spring portion is bent in a manner folded back from the rear end of the press-fitting portion in the inserting direction toward the front side in the inserting direction, and the connecting portion extends from the rear end of the press-fitting portion in the inserting direction of the press-fitting portion toward the rear side in the inserting direction. This makes it possible to reduce the size of the press-fitting portion in the inserting direction. As a consequence, it is not necessary to form openings or slots in the press-fitting portion. 
     Preferably, said press-fitting portion has a protrusion that bites into the housing when said press-fitting portion is press-fitted into the housing. 
     Preferably, said press-fitting portion is a substantially rectangular plate portion extending in a direction orthogonal to the inserting direction of said press-fitting portion and a direction of thickness of said press-fitting portion. 
     More preferably, a connecting end of said spring portion via which said spring portion is connected to said press-fitting portion is positioned toward one longitudinal end of said press-fitting portion; a connecting end of said connecting portion via which said connecting portion is connected to said press-fitting portion is positioned toward the other longitudinal end of said press-fitting portion; and said connecting portion and said spring portion are arranged with a predetermined gap therebetween. 
     Preferably, the contact is formed by pressing a metal plate. 
     In a second aspect of the present invention, there is provided a connector including the contact described above. 
     According to the present invention, it is possible to facilitate the adjustment of impedance, and ensure a high holding force when the contact is held in the housing. 
     The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a front view of contacts and a connector including the same, according to an embodiment of the present invention; 
         FIG. 1B  is a plan view of the connector shown in  FIG. 1A ; 
         FIG. 1C  is an enlarged side view of the connector shown in  FIG. 1A ; 
         FIG. 2  is an enlarged cross-sectional view taken on line II-II of  FIG. 1A ; and 
         FIG. 3  is a perspective view of an upper contact appearing in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described in detail with reference to the drawings showing preferred embodiments thereof. 
     First, a connector including a contact according to an embodiment of the present invention will be described with reference to  FIGS. 1A to 3 . 
     The connector is a card edge connector for connecting a module substrate (one object to be connected), such as a graphic card substrate, not shown, to a motherboard (the other object to be connected) e.g. of a personal computer or a printer, and more particularly a narrow-pitch card edge connector compatible with high-speed signals. 
     Referring to  FIGS. 1A ,  1 B and  1 C, the connector is comprised of upper contacts (contact)  3 , lower contacts  4  and a housing  5 . 
     As shown in  FIGS. 2 and 3 , each upper contact  3  includes a contact portion  31 , a spring portion  32 , a press-fitting portion  33 , a connecting portion  34 , and a terminal portion  35 . The upper contact  3  is formed by pressing a metal plate (not shown). 
     The contact portion  31  is brought into contact with a pad (not shown) formed on the upper surface of the module substrate. 
     The spring portion  32  is substantially J-shaped, and has one end thereof connected to the contact portion  31 . The spring portion  32  presses the contact portion  31  against the pad formed on the upper surface of the module substrate. 
     The press-fitting portion  33  has a substantially rectangular shape. More specifically, the press-fitting portion  33  is a substantially rectangular and elongated plate extending in a direction DH (direction of the height of the press-fitting portion  33 ) orthogonal to a direction DI in which the press-fitting portion  33  is inserted into a holding hole portion  52   b , referred to hereinafter, of the housing  5 , and a direction DT of the thickness of the press-fitting portion  33 . The direction DH of the height of the press-fitting portion  33  is parallel to the longitudinal direction of the press-fitting portion  33 . The press-fitting portion  33  has a lower portion formed with a substantially wedge-shaped protrusion  33   a . The other end (connecting end) of the spring portion  32  is connected to an upper portion of a rear end  33   b  of the press-fitting portion  33  in the inserting direction DI of the press-fitting portion  33 . The other end of the spring portion  32  extends in a direction opposite to the inserting direction DI, from an upper end surface  33   c  of the press-fitting portion  33 , with a portion stepped downward therefrom. The contact portion  31  is positioned forward of the press-fitting portion  33  in the inserting direction DI, and upward of the press-fitting portion  33  in the direction DH of the height thereof. The spring portion  32  is bent from the rear end  33   b  of the press-fitting portion  33  in the inserting direction DI in a manner folded back toward a front side in the inserting direction DI. The press-fitting portion  33  is press-fitted into an associated one of the holding hole portions  52   b  of the housing  5 . When the press-fitting portion  33  is press-fitted into the associated holding hole portion  52   b , the protrusion  33   a  bites into the inner surface of the holding hole portion  52   b , which makes the press-fitting portion  33  difficult to be pulled out from the holding hole portion  52   b.    
     The connecting portion  34  has a substantially rectangular shape. One end (connecting end) of the connecting portion  34  is connected to a lower portion of the rear end  33   b  of the press-fitting portion  33  in the inserting direction DI. The connecting portion  34  is a substantially rectangular and horizontally oriented plate extending in the inserting direction DI. The connecting portion  34  has a connection mark  34   a  indicating that the connecting portion  34  was connected to a carrier (not shown). The connecting portion  34  and the spring portion  32  are arranged with a predetermined gap  36  therebetween. 
     The terminal portion  35  is substantially L-shaped, and is connected to the other end of the connecting portion  34 . The terminal portion  35  is soldered to a pad (not shown) on the motherboard. 
     The width of the spring portion  32  in the direction DH of the height thereof and the width of the connecting portion  34  in the direction DH of the height thereof are substantially equal to each other. 
     Further, the width of the press-fitting portion  33  in the inserting direction DI and the width of the connecting portion  34  in the direction DH of the height thereof are substantially equal to each other. 
     As shown in  FIG. 2 , each lower contact  4  has a contact portion  41 , a terminal portion  43 , and so forth. 
     The contact portion  41  is brought into contact with a pad (not shown) formed on the lower surface of the module substrate. 
     The terminal portion  43  is soldered to a pad (not shown) on the motherboard. 
     Since the lower contact  4  is by far smaller than the upper contact  3 , the impedance matching therebetween does not present a serious problem. The lower contact  4  does not have such a press-fitting portion, a spring portion, and the like, as shaped in the upper contact  3 . 
     The housing  5  is made of a resin having insulation properties. As shown in  FIG. 2 , the housing  5  has a receiving portion  51  formed in a front portion thereof. The receiving portion  51  receives a front end of the module substrate. The front end of the module substrate is configured to be pivotally movable in the receiving portion  51  about the contact portions  41  within a predetermined range of angles. 
     A plurality of first contact-accommodating chambers  52  are formed at equally-spaced intervals in a rear portion of the left half of the housing  5  (the left half of the housing  5  as viewed in  FIG. 1A ) and a rear portion of the right half of the housing  5  (the right half of the housing  5  as viewed in  FIG. 1A ) in a contact arrangement direction DC. A front portion of each first contact-accommodating chamber  52  communicates with the receiving portion  51 , and a rear portion thereof faces the outside of the housing  5 . The first contact-accommodating chamber  52  includes a spring portion-accommodating portion  52   a , the holding hole portion  52   b  and a hollow portion  52   c . The spring portion-accommodating portion  52   a  accommodates an associated one of the spring portions  32  of the upper contact  3 , and has a capacity large enough not to hinder the elastic deformation of the accommodated spring portion  32 . Each press-fitting portion  33  of the upper contact  3  is press-fitted into an associated one of the holding hole portions  52   b  along the inserting direction DI. When the press-fitting portions  33  are inserted into the holding hole portions  52   b , the upper contacts  3  are held in the housing  5 . Each hollow portion  52   c  is interposed between an associated one of the holding hole portions  52   b  and the receiving portion  51 . 
     Referring to  FIG. 1A , second contact-accommodating chambers  53  are formed at equally-spaced intervals in a front portion of the left half of the housing  5  and a front portion of the right half thereof in the contact arrangement direction DC. Although the arrangement pitch of the second contact-accommodating chambers  53  is equal to the arrangement pitch of the first contact-accommodating chambers  52 , the second contact-accommodating chambers  53  and the first contact-accommodating chambers  52  are displaced from each other in the contact arrangement direction DC by half the arrangement pitch. Each lower contact  4  is accommodated in an associated one of the second contact-accommodating chambers  53 . 
     As shown in  FIGS. 1A ,  1 B and  1 C, the opposite ends of the housing  5  in the longitudinal direction thereof are formed with holddown-mounting portions  54 , respectively. Holddowns  7  are mounted on the holddown-mounting portions  54 , respectively. 
     A positioning boss  55  is formed on a lower surface of one longitudinal end of the housing  5 , and a positioning boss  56  is formed on a lower surface of the other longitudinal end of the housing  5 . The positioning boss  55  is thinner than the positioning boss  56 . 
     Next, a description will be given of an example of a method of using the above connector. 
     First, the respective terminal portions  35  of the upper contacts  3 , the respective terminal portions  43  of the lower contacts  4 , and the holddowns  7  are soldered to pads on the motherboard, respectively, to thereby mount the connector on the motherboard. 
     Next, the front end of the module substrate is obliquely inserted into the receiving portion  51  of the connector. After the insertion, the module substrate is pivotally moved about the respective contact portions  41  of the lower contacts  4  such that the front end of the module substrate is moved upward. When the module substrate becomes substantially parallel to the motherboard, the module substrate is brought into abutment with partition walls of the first contact-accommodating chambers  52  whereby the pivotal motion of the module substrate is stopped. In this state, each spring portion  32  is pressed upward by the front end of the module substrate to be elastically deformed, and the contact portion  31  of each upper contact  3  is pressed against an associated one of the pads on the upper surface of the module substrate by the spring force of the spring portion  32 . Further, the contact portion  41  of each lower contact  4  is in contact with an associated one of the pads formed on the lower surface of the module substrate. 
     As a consequence, the module substrate and the motherboard are electrically connected to each other via the upper contacts  3  and lower contacts  4  of the connector. 
     Further, as described above, the spring portion  32  of each upper contact  3  is bent in a manner folded back from the rear end  33   b  of each press-fitting portion  33  in the inserting direction DI toward the front side in the inserting direction DI, and the connecting portion  34  of the upper contact  3  extends from the rear end  33   b  of the press-fitting portion  33  in the inserting direction DI toward the rear side in the inserting direction DI, whereby the connector is configured to prevent the press-fitting portions  33  from forming stubs. This enables reduction of the size of each press-fitting portion  33  in the inserting direction DI. As a consequence, it is not necessary to form an opening or a slot in the press-fitting portion  33 . 
     According to the present embodiment, since the press-fitting portion  33  is prevented from forming a stub, it is possible to facilitate the adjustment of impedance of the contact  3 . Further, since there is no need to form any opening or slot in the press-fitting portion  33 , it is possible to ensure a high holding force when the contact  3  is held in the housing  5 . 
     As described hereinabove, according to the present embodiment, it is possible to facilitate the adjustment of impedance of the contact  3  and ensure a high holding force when the contact  3  held in the housing  5 . 
     Further, in designing a contact such that a desired impedance is obtained, it is possible to facilitate the adjustment of the impedance. 
     It should be noted that although in the present embodiment, the contacts are provided for a board-to-board connector, the scope of application of the present invention is not limited to the board-to-board connector. 
     It is further understood by those skilled in the art that the foregoing are the preferred embodiments of the present invention, and that various changes and modification may be made thereto without departing from the spirit and scope thereof.