Abstract:
An electrical connector comprises a housing ( 12 ) and a substantially rectangular case ( 13 ) made of a metal and enclosing the housing. The rectangular case includes at least one connection portion ( 28 ) on a side of a lower surface thereof for connection with a circuit board, a resilient lock piece ( 20 ) and a pair of shield pieces ( 26 ) between the upper and lower surfaces the rectangular case for engaging a mating connector. The upper surface of the case is made flat for easy assembling with the housing. The resilient lock piece has a bending portion ( 21 ), which is bent toward an inner of the rectangular case and the shield pieces are provided on sides of the resilient lock piece.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to an electrical connector having a housing enclosed and held by a rectangular case made of a metal, especially a USB connector.  
           [0003]    2. Description of the Related Art  
           [0004]    An example of the USB connector is disclosed in Japanese Patent Application Kokai Number 3076855. The UBS connector is standardized and as shown in FIG. 2 of the reference, a receptacle connector, which is fixed to a circuit board, has a metal case of which lower surface is cut downward to provided a fixing leg and part of the upper surface is cut upward to provide a locking arm. The UBS connector shown in FIG. 2 is called a “miniature-type connector”, and has a sectional shape of substantially “T” so as to have the locking arm and a shield piece in the upper side. A plug connector of the UBS connector has a display section on which information, such as the type of the connector, is indicated, and is plugged in the receptor connector with the display section facing upward. The upper surface of the plug connector, in which the display section is provided, has an engagement window to engage the locking arm of the receptor connector.  
           [0005]    The plug connector is plugged in the receptor connector fixed on the circuit board of an electronic apparatus from an opening of a panel or case of the electronic apparatus.  
           [0006]    An electronic apparatus has a convenient direction or orientation for usage and the method of fixing the receptacle connector is changed according to the convenient direction.  
           [0007]    For example, a portable telephone is required to have a small thickness. In addition, a circuit board must be arranged in the vicinity of a display so that electronic components including the connector should be arranged on the lower surface of the circuit board. Consequently, the locking arm of the receptor connector faces downwardly so that the engaging window of the plug connector also faces downwardly. It means that the display section of the plug connector fronts to an opposite direction with the display of the portable telephone so that the user cannot see the display section of the plug connector when he/she is watching the display of the portable telephone. Even if the receptacle connector is used upside down to solve the problem, the locking arm and shield piece cannot obtain a sufficient amount of displacement because they are provided by cutting upward the upper surface of the metal case. Also, it is difficult to provide the locking arm and shield piece on the lower surface of the metal case together with the fixing legs because the fixing legs are provided there by cutting downward the metal case.  
           [0008]    When the receptacle connector is fixed to the circuit board, the receptacle connector is absorbed and held by an automatic machine for pick-up from a container and brought to a predetermined position of the circuit board for solder-connection. However, as described above, the upper surface of the metal case of the receptacle connector is provided with the locking arm so that there is no flat plane having a sufficient space for the absorption. Accordingly, a heat-resistant tape is adhered to the upper surface to enable the automatic absorption prior to the absorption and then taken off after the receptacle connector is soldered to the circuit board, which needs time and labor.  
         BRIEF SUMMARY OF THE INVENTION  
         [0009]    Accordingly, it is an object of this invention to provide an electrical connector with a rectangular case, which can be used while seeing the display and easily assembled automatically.  
           [0010]    According to an aspect of the invention, an electrical connector comprises a housing and a substantially rectangular case made of a metal and enclosing the housing, the substantially rectangular case having a front opening and including at least one connection portion provided on a side of a lower surface of the substantially rectangular case for connection with a corresponding circuit trace of a circuit board, a resilient lock piece provided between an upper surface and the lower surface of the substantially rectangular case and engage a mating connector, and a pair of shield pieces provided between the upper and lower surfaces and brought into contact with a shield case of the mating connector, wherein the upper surface is made flat, the resilient lock piece has a bending portion at the front opening of the substantially rectangular case, which is bent from the lower surface toward an inner of the substantially rectangular case, and the shield pieces are provided on sides of the resilient lock piece.  
           [0011]    According to such an electrical connector, when the display section of an electronic apparatus, such as a portable telephone, faces upward, electronic components, such as the electrical connector are positioned under a circuit board. When mounted on the circuit board, the electronic components are absorbed and transported by an automatic machine and soldered onto the circuit board at a predetermined position under the condition that the circuit board is turned upside down. The electrical connector according to the present invention is easily absorbed by the machine because the upper surface of the rectangular case is made flat.  
           [0012]    When the apparatus is used, the connector is turned over with the circuit board, from the posture when it mounted to the circuit board so that the resilient lock piece is positioned on the side of the display of the apparatus, enabling the user to plug in the mating connector watching the display thereof.  
           [0013]    The substantially rectangular case is made by bending a metal sheet around an axis of the substantially rectangular case or a plugging direction of the mating connector and has a joint of edges of the metal sheet on the upper surface. In that case, it is preferable that the joint is not present in the center of the upper surface so that the connector can be absorbed at the center by an automatic machine.  
           [0014]    It is more preferable that the substantially rectangular case is made by bending a metal sheet around an axis of the substantially rectangular case or a plugging direction of the mating connector and has a joint of edges of the metal sheet on a side surface thereof so that the upper surface has no joint and is made completely flat.  
           [0015]    Its is also preferable that the bent portion has a curvature to smoothly guide the mating connector.  
           [0016]    The substantially rectangular case can have a lower opening in at least part of the lower surface to accommodate a bottom section of the housing. The housing is made of an insulating material so that even if a circuit section is provided at a corresponding position of the circuit board, there is no risk that the circuit section is short-circuited by the close approach or contact of the bottom section of the housing to or with the circuit section. Thus, the circuit section is arranged at the corresponding position effectively.  
           [0017]    The substantially rectangular case has a projection portion extending forwardly from part of an edge of the front opening thereof. If the projection portion is inserted into a window of a front panel of the apparatus, the positioning of the connector is easily performed with respect to the window.  
           [0018]    If a lower side of the bent portion of the resilient lock piece is positioned lower than that of a plane where the housing is fixed to the circuit board, part of the thickness of the bent portion is within the thickness of the circuit board so that the influence of the thickness of the bent portion on the height of apparatus is minimized. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a perspective view of a receptacle connector according to an embodiment of the present invention and a mating plug connector prior to plug-in, with bottoms thereof facing upward.  
         [0020]    [0020]FIG. 2 is an upper perspective view of the receptacle connector of FIG. 1 FIG. 3(A) is a front view of the receptacle connector of FIG. 2.  
         [0021]    [0021]FIG. 3(B) is a sectional view of the receptacle connector of FIG. 3(A) taken along the line B-B.  
         [0022]    [0022]FIG. 4 is a perspective view of a shield case of the receptacle connector of FIG. 2.  
         [0023]    [0023]FIG. 5 is a perspective view of a housing of the receptacle connector of FIG. 2.  
         [0024]    [0024]FIG. 6 is a perspective view of a housing of a receptacle connector according to another embodiment of the present invention.  
         [0025]    [0025]FIG. 7 is a perspective view of the receptacle connector of FIG. 6 in use.  
         [0026]    [0026]FIG. 8 is a sectional view of the receptacle connector of FIG. 7.  
         [0027]    [0027]FIG. 9 is a sectional view of a receptacle connector according to still another embodiment of the present invention. FIG. 10 is a sectional view of a receptacle connector according to yet another embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    Embodiments of the present invention will now be described with reference to the accompanying drawings.  
         [0029]    [0029]FIG. 1, reference numeral  10  denotes a receptacle connector according to an embodiment of the present invention and  30  a mating plug connector to be plugged in the receptacle connector  10 .  
         [0030]    The bottom surface of the receptacle connector  10  shown in FIG. 1 faces upwardly so that it can be fixed to the lower surface of a circuit board (not shown) of an electronic apparatus. However, the receptacle connector  10  shown in FIG. 2 and after that faces downwardly to facilitate the understanding.  
         [0031]    As shown in FIGS. 1 and 2, the receptacle connector  10  comprises a housing  12 , a plurality of terminals  11  provided in the housing  12 , and a shield case  13  having a form of substantially rectangular tube (hereinafter “rectangular case”) and enclosing substantially entire part of the housing  12 .  
         [0032]    In FIGS.  2 - 5 , the housing  12  is made of an electrically insulating material and comprises a rear section  14  having a pair of shoulders  14 A at an upper side thereof, a projecting section  15  extending forwardly from the upper portion of the rear section  14 , and a bottom section  19  extending forwardly from the lower portion of the rear section  14 . Each of the shoulder  14 A has a slope  14 B and a dent  16  having a depth corresponding to the thickness of the rectangular shield case  13  between the shoulders  14 A. The rear section  14  has a hollow  17  opened rearwardly.  
         [0033]    The projecting section  15  is made small than the rear section  14  by the dimension of the thickness of the shield case  13  so that the base portion of the projecting section  15  is stepped with respect to the rear section  14 . The projecting section  15  comprises a pair of slopes  15 A extending substantially in parallel to the slopes  14 B. A plurality of terminal slots  18  extend through the projecting section  15  in the back-and-fourth direction to accommodate the terminals  11 . The terminals  11  are bent in a crank form and each terminal  11  is inserted into the terminal slot  18  from the rear side such that the front end thereof remains inside the terminal slot  18  to make a contact portion and the L-shaped rear end extends downwardly from the terminal slot  18  to make a connection portion  11 A at the substantially same level with the bottom of the housing  12 .  
         [0034]    The bottom section  19  extends forwardly from the rear section  14  in parallel with the projecting section  15  and comprises side ribs  19 A and center ribs  19 B provided at the sides and center thereof, respectively. Circular thin projection  19 D are provided in a bottom surface  19 C (upper side surface in FIG. 1) of the bottom section  19 .  
         [0035]    The shield case  13  is made by stamping a metal sheet in a predetermined unfolded form and bending or folding it in a designated way. In this embodiment, a bent portion  21  is folded inside to provide a resilient lock piece  20  before forming a shape of the rectangular shield case. Upon forming the rectangular shield case  13 , both edges of the metal sheet are stamped to have square waves so that they are joined at a joint  22  such that the square waves of both the edges fit each other. Especially, the joint  22  has a big square wave in the center to bypass the center of the upper surface of the shield case  13  (FIG. 2). That is, no joint  22  is present in the center of the upper surface. The joint  22  may be press-crushed or bent-joined or overlapped with each other to strengthen the joining force.  
         [0036]    The shield case  13  has a projection  23  in the upper surface thereof which extends rearwardly to be plugged in the dent  16  of the housing  12 , and cut-off portions  24  at sides of the projection  23  to receive the upper part and the slops  14 B of the shoulder  14 A. When the housing  12  is inserted into the shield case  13 , the upper face of the shield case  13  including the projection  23  is substantially flush with the upper part of the shoulders  14 A of the housing  12 . Also, as shown in FIG. 1, when the bottom section  19  of the housing  12  is accommodated in the open section of the bottom  25  of the shield case  13 , the bottom  25  of the shield case  13  is substantially flush with the bottom surface  19 C of the bottom section  19  of the housing  12 .  
         [0037]    The resilient lock piece  20  of the shield case  13  extends inside the shield case  13  substantially in parallel with the bottom  25  of the shield case  13  through the bent portion  21  having a curvature. A pair of shield arms  26  are provided on sides of the resilient lock piece  20 . The area including the resilient lock piece  20  and the shield arms  26  has a width smaller that that of the bent portion  21  such that the area is within the ribs  19 A provided on the sides of the bottom section  19  of the housing  12 . A U-shaped kerf  27  is provided within the area to define the resilient lock piece  20  in the inside of the U-shape. A locking hook  20 A is provided at the end of the resilient lock piece  20 . The shield arms  26  are integrally made with the resilient lock piece such that they extend forwardly from the inner part of the kerf  27  in parallel with the resilient lock piece. The shield arms  26  are provided with contact portions  26 A which is swollen at the front of S the front opening of the shield case  13  to be brought into resilient contact with a shield member of the mating connector. It is possible to make a lock piece extending outwardly or in the same direction as the shield arms by providing a kerf in a form of reverse-U.  
         [0038]    Connection legs  28  extending downwardly and supporting legs  28 A bent inside afterwards are provided at sides of the bottom surface of the shield case  13 .  
         [0039]    The housing  12  carrying the terminals  11  is assembled into the shield case  13  to provide the receptacle connector  10 . The housing  12  is inserted into the shield case  13  from the rear side of the shield case  13 . The stepped front of the rear section  14  of the housing  12  abuts against the rear end of the shield case  13  for positioning. The resilient lock piece  20  and shield arms  26  are positioned between the projecting section  15  and the bottom section  19  of the housing  12 . As describe above, the bottom section  19  of the housing  12  is flush with the bottom  25  of the bent portion  21  of the shield case  13 , and the connection portion  11 A of the terminals  11  is also positioned in the same plane.  
         [0040]    The housing  12  is supported or held by bending the supporting legs  28 A of the shield case  13  (FIG. 1).  
         [0041]    As shown in FIG. 1, the mating plug connector  30  comprises a plug projection which is enclosed by a shield case  31 . The shield case  31  has a shape suitable for plugging in the shield case  13  of the receptacle connector  10  and comprises an engaging window  32  in the upper surface thereof to engage the lock locking hook  20 A of the resilient lock piece  20  of the receptacle connector  10 . A display section  33  is provided in the upper surface of the body of the plug connector  30 .  
         [0042]    How to use the connector according to the present invention will be described below.  
         [0043]    1. The receptacle connector  10  in the posture shown in FIG. 2 is absorbed by the automatic machine with an absorber, which absorbs the connector  10  at the upper center of the connector  10 , and transported to a predetermined position of a circuit board (not shown) which has not been assembled into the electronic apparatus.  
         [0044]    2. Then, the receptacle connector  10  is connected to a predetermined position of the circuit board by soldering. That is, the connection legs  28  are inserted into holes provided in a circuit section of the circuit board and connected by soldering to the circuit section for grounding, and the connection portions  11 A of the terminals  11  are connected to corresponding circuit trances by soldering. The connection legs  28  may have a SMT shape instead of a DIP shape. Alternatively, the lower surface of the shield case  13  may be directly fixed to the grounding circuit section.  
         [0045]    3. The front opening of the receptacle connector  10  is usually positioned at the window of the panel of the electronic apparatus. For example, in case of a portable telephone, the circuit board is fixed to the telephone after turning the circuit board upside down so as to place the receptacle connector  10  under the circuit board so that the mating connector can be inserted into the receptacle connector  10  from the window with the display of the portable telephone facing upward. FIG. 1 shows the posture of the connector  10  in this condition.  
         [0046]    4. Consequently, the plug connector  30  is plugged in the receptacle connector  10  through the window of the panel of the electronic apparatus with the display section  33  thereof facing upward, thus connecting the terminals of both the connectors  10  and  30 .  
         [0047]    5. The contact portions  26 A of the shield arms  26  of the with shield case  31  of the plug connector  30  and the locking hook  20 A of the receptacle connector  10  is engaged with the engaging window of the shield case  31  to prevent the slip off of the connectors  10  and  30 .  
         [0048]    The present invention is not limited to the embodiments shown in FIGS.  1 - 6 , and various modifications are possible.  
         [0049]    For example, in FIGS. 7 and 8, a projection piece  29  extends forwardly from part of the front opening edge of the shield case  13  so that the projection piece  29  abuts against a panel window P 1  provided in a front panel P of the electronic apparatus to facilitate the positioning. Accordingly, the joint portion  22  is strengthen against the forced insertion of or strong push by the plug connector  10 .  
         [0050]    In FIG. 9, a lower side  25  of the bent portion  21  of the shield case  13  is positioned lower than that of a plane where the connector is fixed to a circuit board Q so that part of the thickness of the bent portion  21  falls into the range of the thickness of the circuit board Q, resulting in a low profile of the connector. In this case, a through space  19 E extending up to the lower part of the bottom section  10  of the housing  12  is provided between the ribs  19 A and  19 B to permit the resilient lock piece  20  to flex to the through space  19 E, thus contributing to the low profile of the housing  12 . The supporting legs  28 A of the housing  12  may extend rearwardly and bent behind the housing  12  to support the housing  12 .  
         [0051]    In FIG. 10, since the joint portion  22  of the shield case  13  is provided in the side surface of the shield case  13  instead of the upper surface thereof, no joint portion  22  is present in the upper surface. Accordingly, when absorbing the connector to assemble it the circuit board, it is not necessary to exactly adjust the absorption position at the center of the shield case  13 .  
         [0052]    As fully described above, according to the present invention, the upper surface of the shield case enclosing the housing is made flat and the resilient lock piece is provided on the side of the lower surface thereof so that the connector can be absorbed easily at the upper surface by automatic machine and even if the connector is used upside down to minimize the size of the apparatus, the mating plug connector (USB connector) can be plugged in, while watching the display portion thereof.