Abstract:
A card connector assembly having intermediate contacts with dimensions corresponding to the attachment height at which an insulating housing that accommodates a card is attached to a board. Signal contacts are attached to the insulating housing and are connected to the card. A ground plate is ground-connected with the card. The contacts and the ground plate are connected to the board. Intermediate contacts are disposed in the insulating housing. One end of each of the intermediate contacts is ground-connected to the board. The ground plate is ground-connected to the board via the intermediate contacts. Accordingly, even if the attachment height at which the connector assembly is attached to the board should vary, the dimensions of the intermediate contacts can easily be adjusted to accommodate the difference in height.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a card connector assembly, and more specifically, to a board-attached type card connector assembly attached to a board.  
         DESCRIPTION OF THE PRIOR ART  
         [0002]    A conventional board-attached type card connector assembly has numerous contacts that are directly soldered to a board and disposed in an insulating housing. The insulating housing accommodates a card (memory card). The card is ground to the board via spring fingers that contact the metal surfaces (frame ground) on the side surfaces and attachment brackets that are connected to the spring fingers. The ground frame discharges any charge accumulating on the card, so that the integrated circuits (IC) in the card are protected from static electricity. One embodiment of this type of assembly is disclosed in U.S. Pat. No. 5,288,247. A second type of assembly is disclosed in Japanese Patent Application Kokai No. H8-241764. The second assembly has signal grounds located in the vicinity of the front end of the card that contact a ground plate. The ground plate is connected to the board via a flexible wiring board and relay connector. The signal contacts are similarly connected to the board via the flexible wiring board and a relay connector that is connected to the wiring board.  
           [0003]    A board mount card connector assembly requires a plurality of different attachment heights for a card connector assembly depending on the desired application. Because the parts in which the spring fingers and attachment brackets are connected cannot handle a plurality of types of card connectors with different heights, a plurality of different types of card connector assemblies and molds must be prepared according to the attachment height. Although variations in height can be handled more easily by the flexible circuit board, the number of parts required is still extensive, thereby increasing manufacturing costs.  
           [0004]    It is therefore desirable to develop an inexpensive board mount card connector assembly that can accommodate various attachment heights of the board mount card connector assembly to the board.  
         SUMMARY OF THE INVENTION  
         [0005]    This invention relates to a board mount card connector assembly having an insulating housing that accommodates a card attached to a board. Signal contacts are attached to the insulating housing and are connected to the card that is inserted into the insulating housing. A ground plate is ground-connected with the card. The contacts and the ground plate are connected to the board. Intermediate contacts are disposed in the insulating housing and have dimensions corresponding to the attachment height at which the insulating housing is attached to the board. One end of each of the intermediate contacts is ground-connected to the board. The ground plate is ground-connected to the board via the intermediate contacts. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]    [0006]FIG. 1(A) is a schematic plan view of the card connector assembly,  
         [0007]    [0007]FIG. 1(B) is a partial enlarged view showing an enlargement of the rear part of the shielding shell used in the card connector assembly, and  
         [0008]    [0008]FIG. 1(C) is a sectional view of the shielding shell along line C-C of FIG. 1 (B).  
         [0009]    [0009]FIG. 2 is a plan view of the insulating housing of the card connector assembly shown in FIG. 1.  
         [0010]    [0010]FIG. 3 is a side view of the insulating housing shown in FIG. 2.  
         [0011]    [0011]FIG. 4 is a sectional view of the insulating housing along line  4 - 4  of FIG. 2.  
         [0012]    [0012]FIG. 5 is a plan view of the ground plate.  
         [0013]    [0013]FIG. 6 is a side view of the ground plate.  
         [0014]    [0014]FIG. 7 is a plan view of the card connector assembly.  
         [0015]    [0015]FIG. 8 is a side view of the card connector assembly shown in FIG. 7.  
         [0016]    [0016]FIG. 9 is a sectional view of the card connector assembly along line  9 - 9  of FIG. 7.  
         [0017]    [0017]FIG. 10 is a plan view of a first intermediate contact used in the card connector assembly.  
         [0018]    [0018]FIG. 11 is a side view of the first intermediate contact shown in FIG. 10.  
         [0019]    [0019]FIG. 12 is a plan view of a first nut used in the card connector assembly of the present invention.  
         [0020]    [0020]FIG. 13 is a front view of the first nut shown in FIG. 12. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    Shown in FIG. 1, the assembly  1  is equipped with an insulating housing  2  that has signal contacts  6  in the rear part. A metal shielding shell (frame)  4  is attached to the front part of the housing  2 . The shell  4  is formed so that it is substantially plate-shaped, and is constructed so that a card  10  (i.e., memory or PC card) can be accommodated inside via an opening in the front part  5 . The shell  4  surrounds the card, meaning that the card can either be completely covered or partially exposed to the outside. Guides are disposed on both the left and right sides of the shell  4  to guide the card. The guides are formed by metal members that are integral parts of the shell  4  or by a synthetic resin. In this case, the left and right guides of the shell  4  guide the card  10 .  
         [0022]    An operating rod  8  is attached to the shell  4  and has a knob  12  on its tip end so that the rod  8  is free to slide. The end portion  7  of a cam bar is connected to the tip end of the operating rod  8  and is accommodated inside the housing  2  so that the cam bar is free to rotate. When the knob  12  is pushed, the cam bar is driven, ejecting the card  10  inserted into the shell  4 .  
         [0023]    The ground connection of the card  10  will now be described. A metal plate (not shown) covers the outside of the card  10 . When the card  10  is inserted into the shell  4 , the metal plate contacts spring parts  22  that protrude inside the shell  4 . Tongue parts (conductive parts)  16 , shown in FIG. 1(B), are formed by being cut and raised inside rectangular openings  17  on both sides of the shell  4  near the rear edge  18  of the shell  4 . The tongue parts  16  extend rearward and are inclined toward the housing  2 .  
         [0024]    A ground plate  20  is carried on the upper surface of the housing  2 . The shell  4  is attached to the surface of the ground plate  20 . Electrical continuity is established when the tongue parts  16  contact the ground plate  20 . Here, the surface of the ground plate  20  that contacts the tongue parts  16  acts as a conductive part. As a result, the outer surface of the card  10 , the shell  4 , and the ground plate  20  are electrically connected so that the parts form an integrated unit in electrical terms.  
         [0025]    A plurality of rectangular openings  19  is formed along the rear edge  18  of the shell  4 . To allow for the proper displacement of the tongue parts  78 , the openings  19  are formed in positions corresponding to the tongue parts  78  on the ground plate  20  (FIGS. 5 and 7). Latch parts  21  having rectangular openings  21   a  are formed by being bent toward the housing on both sides of the rear edge  18  of the shell  4  (FIG. 1(C)). The latch parts  21  engage with latching projections  122  (FIGS.  1 (A),  3  and  8 ) of the housing  2 , fastening the shell  4  to the housing  2 .  
         [0026]    The housing  2  of the assembly  1  will be described with reference to FIGS. 2 through 4. The shape of the housing  2 , as seen in a plan view, is a long, slender, substantially rectangular shape (FIG. 2). In the housing  2 , a bottom wall  24 , side walls  26  positioned on both sides of the bottom wall  24 , and a rear wall  28  connecting both side walls  26 ,  26 , are molded as an integral unit from a synthetic resin. On the rear parts of both ends of the housing  2 , rectangular attachment seats  34 , in which holes  32  are formed, are molded as integral units with the side walls  26  and rear wall  28 . The upper side of the housing  2  forms a space causing the area to the front of the rear wall  28  to be open.  
         [0027]    A recessed surface  36  formed substantially in the same plane in the upper surface of the rear wall  28 , drops slightly downward from the upper surfaces of both side walls  26  via steps  50 . Ribs  38  are formed at specified intervals on the front part of the rear wall  28  and protrude slightly from the recessed surface  36 . Three projections  40  are formed on the recessed surface  36  in positions that correspond to the gaps G between the ribs  38  and are located to the rear of the ribs  38  (below the ribs in FIG. 2). The projections  40  have a cross-sectional T shape, and have grooves  40   a  on both sides. A long, narrow extended slot  38   a  is formed along the recessed surface  36  in each rib  38  and passes through each rib  38  in the forward-rearward direction. A recessed part  42 , which is slightly lower than the recessed surface  36 , is formed in the recessed surface  36  behind each of the slots  38   a . The slots  38   a  are positioned at the same height as the recessed parts  42 . A rib  39  is caused to protrude from the rear end of the rear wall  28 . The rib  39  extends along substantially the entire length of the rear wall  28  of the housing  2   
         [0028]    A plurality of holding projections  46  are formed along the rear wall  28  on the rear end  44  of the housing  2 . Holding grooves  48  are formed between adjacent holding projections  46  and position the contacts  6 . At both ends of the row of holding grooves  48 , cut-outs  49  are formed in positions corresponding to the rear-facing surfaces  60  of the rear part of the housing  2 .  
         [0029]    Rectangular tongue parts  52  are caused to protrude inward, parallel to the bottom wall  24 , on the insides and near the tip ends of the respective side walls  26 . Rectangular protruding parts  53  that have the same height as the rectangular tongue parts  52  are formed on the respective side walls  26 . Flat projections  56  protrude from the bottom wall  24  at substantially uniform intervals. The projections  56  regulate the swinging motion of the cam bar disposed on the bottom wall  24 . A slot  58 , extending in the forward-rearward direction, is formed on the side wall  26  in the vicinity of the bottom wall  24  (FIG. 3). The cam bar protrudes from the slot  58  and is connected to the operating rod  8 .  
         [0030]    Shown in FIG. 4, recessed grooves  62  are formed at both ends of the row of holding projections  46  of the housing  2 . The recessed groves  62  extend forward (to the left in FIG. 4) parallel to the bottom wall  24  from the rear-facing surface  60  of the housing  2 . The inside surface on the lower side of the groove is formed parallel to the bottom wall  24 , while the inside surface on the upper side is formed with a taper  63  so that the groove becomes narrower moving inward. The housing  4  contains an opening  66  for insertion of the card  10  (FIG. 4). A projecting strip  68 , used to prevent erroneous insertion of the card  10 , protrudes inward and is formed from a long, slender part that extends in the forward-rearward direction on the inside surface of one side wall  26 . A second projecting strip protrudes on the opposite side wall opposite from the projecting strip  68 .  
         [0031]    The upper surface of the housing  2  carries a ground plate  20  (FIGS. 5 and 6). The ground plate  20  is substantially rectangular in shape and is formed by stamping and bending a single metal plate. A plurality of rectangular openings  76  is formed along the front edge  74  of the main surface  72  of the ground plate  20  in the vicinity of the front edge  74 . Tongue parts (contact parts)  78  are formed in the openings  76  and extend rearward. Projections  80  protrude downward from the main surface  72  (i.e., toward the housing  2 ) and are formed by stamping between adjacent openings  76 . The projections  80  limit the upward movement of the card  10  in order to prevent the card  10  from interfering with and deforming the tongue parts  78  when the card  10  is removed. The projections  80  also prevent a decrease in the strength of the ground plate  20  from the formation of numerous openings  76 .  
         [0032]    On the rear edge  82  of the ground plate  20 , an extension part  86  drops slightly toward the opposite side of the plane of the page as a result of a step part  84  formed parallel to the main surface  72  as an integral part along the rear edge  82 . T-shaped holes  88  are formed in the extension part  86  in positions corresponding to the T-shaped projections  40 . Cut-outs  90  are formed adjacent to the respective T-shaped holes  88  in positions corresponding to the slots  38   a . Anchoring parts  92  extend in the opposite direction from the extension part  86 . The anchoring parts  92  protrude into the cut-outs  90 . Grounding tongue parts  94  protrude near both ends of the rear edge  82 . The grounding tongue parts extend rearward and are then bent back forward in an approximate U shape (FIG. 6). Contact parts  96  are formed on the lower side as a result of the grounding tongue parts  94  being bent. The contact parts  96  have bent contact points  98  that are bent so that the contact points protrude downward. Rectangular recesses  100  are formed adjacent to cut-outs  102  which open to the front near both ends of the front edge  74  of the ground plate  20 .  
         [0033]    The assembly  1  in which the ground plate  20  is attached to the housing  2  will be described with reference to FIGS. 7 through 9. The assembly  1  is shown with the contacts  6  omitted.  
         [0034]    The ground plate  20  is placed on the side walls  26  and rear wall  28 . The holes  88  in the ground plate  20  are engaged by the T-shaped projections  40  of the housing  2 . The anchoring parts  92  engage with the slots  38   a  to prevent the separation of the rear edge  82  of the ground plate  20  from the housing  2 . The cut-outs  102  of the ground plate  20  engage with the protruding parts  53  of the housing  2 . The recesses  100  are engaged beneath the rectangular tongue parts  52  of the housing  2 , so that the separation of the front edge  74  of the ground plate  20  from the housing  2  in the upward direction is prevented. As a result of the engagement of the protruding parts  53  and the cut-outs  102  as well as the engagement of the extension part  86  and the rib  39 , the movement of the ground plate  20  in the forward-rearward direction is stabilised.  
         [0035]    In this case, shown most clearly in FIG. 9, the contact parts  96  of the grounding tongue parts  94  of the ground plate  20  are disposed inside the recessed grooves  62  of the housing  2 . The intermediate contacts  110  are press-fitted inside the recessed grooves  62  (FIGS. 10 and 11). Each intermediate contact  110  is formed by stamping and bending from a single metal plate, and has a long, slender, substantially rectangular press-fitting part  112 . A leg part  114  is bent downward at right angles from this press-fitting part  112  (in FIG. 11). A tine part (solder connection part)  116  is bent parallel to the press-fitting part  112  and in the opposite direction from the press-fitting part at the lower end of the leg part  114 . The leg part  114  and tine part  116  have the same width, which is narrower than the width of the press-fitting part  112 .  
         [0036]    The press-fitting part  112  has a barb  119  on each side edge  118 . The press-fitting part  112  is press-fitted in the recessed groove  62  causing the inside walls of the recessed grooves  62  and the barbs  119  to interfere and engage with each other, so that the press-fitting part is held inside the recessed groove  62 . Further, when the press-fitting part  112  is press-fitted in the recessed groove  62 , the bent contact point  98  is pushed upward and the press-fitting part  112  makes electrical contact with the bent contact point  98  (FIG. 9).  
         [0037]    The tine part  116  is positioned on the pad of a circuit trace (not shown) on the board  120  that is attached to the assembly  1 . The leg part  114  is held in the cut-out  49  of the housing  2 , so that the tine part  116  is accurately positioned on the pad. As a result, the ground plate  20  is ground-connected to the board  120  via the intermediate contacts  110 .  
         [0038]    Since the intermediate contacts  110  have relatively short dimensions, the coplanarity (i.e., the dimensional precision of the height of the tine parts  116 ) can be increased, so that the planarity with the tine parts of the contacts  6  can be increased. Further, in cases where the attachment height at which the housing  2  is attached to the board  120  varies, it is necessary to change only the shape of the contacts  6  and the dimensions of the leg parts  114  of the intermediate contacts  110 . Hence, there is no need to manufacture a plurality of different types of ground plates  20  with complicated shapes and large dimensions. The same ground plate  20  can be applied to different types of assemblies.  
         [0039]    In cases where the card  10  has signal grounds  11  near the tip end portion of the card  10  (FIG. 9), the tongue parts  78  contact the signal grounds  11 , so that a ground connection is established with the board  120  via the ground plate  20  and intermediate contacts  110 . Similarly, the grounds on the outside surface of the card  10  (i.e., the frame grounds) are ground connected to the board  120  via the intermediate contacts  110  as a result of the contact between the outside surface of the card and the spring parts  22 , and the contact between the tongue parts  16  and the ground plate  20 . In the alternative, instead of using both ground connections, either one or the other of the ground connections could be used (i.e., signal grounds and frame grounds).  
         [0040]    The support nuts  130  that are mounted on the attachment seats  34  of the housing  2  will be described with reference to FIGS. 12 and 13. Each nut  130  is carried on the corresponding attachment seat  34 . The nut  130  is fastened by means of a bolt (not shown) from the side of the board  120 , so that the attachment seat  34  and board  120  are fastened together, fastening the assembly  1  to the board  120 . The nuts  130  have a shape that is similar to the shape of the attachment seats  34  and two types of nuts are prepared in accordance with the left and right attachment seats  34  (FIG. 12 shows the nut  130  corresponding to the right-side attachment seat  34  in FIG. 2). The nut  130  is an aluminium die-cast part, and has a flat part  132  with the same shape as the attachment seat. A tubular part  134  protrudes downward from the flat part  132  as an integral part of the flat part  132  in a position corresponding to the hole  32  in the flat part  132 .  
         [0041]    The external diameter of the tubular part  134  is sized so that it may be inserted into the hole  32  of the corresponding attachment seat  34 . A female screw  136  is formed on the inside of the tubular part  134  and engages with the bolt. When the nut  130  is mounted on the attachment seat  34 , so that the tubular part  134  is inserted into the hole  32 , the nut  130  is positioned as shown by the dashed line in FIG. 4. Since the nut  130  is die-cast, the attachment strength is extremely high, and the impact resistance is large. Hence, even if a large impact is applied to the attachment part, for example as a result of a device equipped with the assembly being dropped, damage is prevented.