Patent Publication Number: US-6217378-B1

Title: Universal serial bus connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an electrical connector, and in particular to a low profile, completely enclosed universal serial bus (USB) connector. 
     2. The Prior Art 
     A universal serial bus (USB) connector is commonly used in computer systems and networks. FIG. 1 shows a conventional USB connector which comprises an insulative body  5  having a top wall, a bottom wall and side walls for receiving and retaining contact elements  7  therein. A shielding casing  6  comprises top, bottom and side sections enclosing the insulative body  5  for protecting the contact elements  7  from electromagnetic interference (EMI). The shielding casing  6  is stamped from a metal sheet and the bottom section thereof forms boardlocks  61  engaging with holes defined in a circuit board  8  for retaining the USB connector on the circuit board  8 . An example of the conventional USB connector is disclosed in Taiwan Patent Nos. 85212192 and 86207969. 
     The boardlocks  61  of the conventional USB connector are stamped on the bottom section of the connector thereby partially exposing the insulative body  5 , leading to the deterioration of EMI protection properties. Furthermore, arranging the boardlocks  61  on the bottom side of the connector hinders the possibility of reducing the overall height of the connector above the circuit board  8 . 
     Moreover, the contact elements  7  of the conventional USB connector are inserted into the insulative body  5  in a direction substantially parallel to a mating force applied thereto when engaging with a mating connector. This may result in displacement of the contact elements during engagement with the mating connector. 
     It is thus desirable to have an electrical connector that overcomes the problems mentioned above. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide an electrical connector comprising an insulative body completely enclosed by a shielding casing. 
     Another object of the present invention is to provide an electrical connector that has a low profile when mounted to a circuit board. 
     A further object of the present invention is to provide an electrical connector comprising contact elements that soundly withstand a mating force applied thereto by a mating connector. 
     To achieve the above objects, an electrical connector in accordance with the present invention comprises a shielding casing having a top section and a bottom section connected to each other by a rear section and two side sections to define an interior space therebetween. The shielding casing defines a front opening for receiving a mating connector in the interior space. Each side section has a projection transversely extending in opposite directions and forming a board lock. An insulative body is fixed in the interior space and spaced from the top, bottom and side sections of the shielding section for receiving the mating connector. The insulative body retains contact elements therein for electrically engaging with contacts of the mating connector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the accompanying drawings, in which: 
     FIG. 1 is a front view of a conventional USB connector mounted on a circuit board; 
     FIG. 2A is a perspective view of an electrical connector constructed in accordance with the present invention; 
     FIG. 2B is another perspective view of the electrical connector of the present invention; 
     FIG. 3A is an exploded view of the electrical connector of the present invention; 
     FIG. 3B is another exploded view of the electrical connector of the present invention; 
     FIG. 3C is a further exploded view of the electrical connector of the present invention; and 
     FIG. 4 is a front view of the electrical connector of the present invention mounted on a circuit board. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings and in particular to FIGS. 2A and 2B, a universal serial bus (USB) connector constructed in accordance with the present invention comprises a conductive shielding casing  1  having a top section  11  and a bottom section  12  connected by a rear section  13  to define an interior space therebetween for receiving an insulative body  2 . The shielding casing  1  defines a front opening  10  for releasably receiving a mating connector (not shown). 
     As shown in FIGS. 3A,  3 B and  3 C, the shielding casing  1  is made by stamping and bending a metal sheet to form the top section  11 , the rear section  13  and the bottom section  12 . Top and bottom flanges (not labeled) extend from opposite edges of the top and bottom sections  11 ,  12  and contact each other to form side sections  14  of the shielding casing  1 . Each top flange extending from the top section  11  has a first transverse extension  140  offset from and substantially parallel to the top section  11 . Each bottom flange extending from the bottom section  12  has a second transverse extension  141  offset from and substantially parallel to the bottom section  12 . The first transverse extensions  140  overlap the corresponding second transverse extensions  141  to form side projections of the shielding casing  1 . Each second transverse extension  141  forms two opposite tabs  143  which are bent to overlap and thus secure the first transverse extension  140  to the second transverse extension  141 . Preferably, each first transverse extension  140  defines a pair of recesses  144  in opposite edges thereof for receiving the tabs  143  of the second transverse extension  141 . Each second transverse extension  141  further forms a pair of spaced resilient barbs  142  to serve as a boardlock which, as shown in FIG. 4, is received in a corresponding hole  40  defined in a circuit board  4  for mounting the connector to the circuit board  4 . 
     The top section  11  and the bottom section  12  of the shielding casing  1  form resilient arms  110  having an inward projection  111  extending into the interior space of the shielding casing  1  for engaging with the mating connector and thus mechanically retaining the mating connector and establishing electrical engagement therebetween for grounding purposes. 
     The insulative body  2  defines a plurality of grooves  210  in a face  21  thereof for receiving contact elements  3  therein. The insulative body  2  is spaced from the top section  11 , the bottom section  12  and the side sections  14   47  of the shielding casing  1  for receiving the mating connector therein to establish electrical connection between the contact elements  3  and the mating connector. 
     The insulative body  2  comprises a back plate  20  in which channels  200  are defined corresponding to and in communication with the grooves  210 . Each channel  200  has two opposite inside faces  203  each defining a slit  202  therein. 
     Each contact element  3  comprises a mating section  30  and a mounting section  32  offset from and substantially parallel to the mating section  30 . A retention section  31  substantially normal to both the mating section  30  and the mounting section  32  is formed therebetween. The retention section  31  has two side projections  33  interferentially received and retained in the slits  202  of the corresponding channel  200  with the mounting section  32  extending beyond the back plate  20  through the channel  200  and the mating section  30  received in the groove  210 . 
     Since the retention section  33  is substantially normal to the mating section  30 , a mating force applied to each contact element  3  while engaging the mating connector with the USB connector is substantially normal to the back plate  20  and absorbed thereby. Thus, the contact element  3  is firmly retained and will not be displaced by the mating force. 
     The shielding casing  1  forms an opening  132  (FIG. 2B) between the rear section  13  and each side section  14  for receiving a lateral end of the back plate  20  with the back plate  20  abutting against an inside face of the rear section  13  thereby securely fixing the insulative body  2  in the shielding casing  1 . The back plate  20  of the insulative body  2  forms a top block  201  and two bottom blocks  203  which are respectively received in openings  131 ,  133  defined in the top section  11  and the bottom section  12  of the shielding casing  1  for retaining the insulative body  2  in the shielding casing  1 . The back plate  20  further comprises a rear block  204  received in an opening  130  defined in the rear section  13  of the shielding casing  1  for further retaining the insulative body  2  in the shielding casing  1 . The mounting sections  32  of the contact elements  3  extend beyond the casing  1  through the rear opening  130 . 
     Preferably, the mounting sections  32  of the contact elements  3  lie in the same plane as the second transverse extensions  141  of the shielding casing  1  whereby when the connector is mounted to the circuit board  4  with the second transverse extensions  141  supported on the circuit board  4 , the mounting sections  32  of the contact elements  3  are positioned to be surface mountable on the circuit board  4 . 
     The transverse extensions  140 ,  141  allow the connector to be mounted to an edge of the circuit board  4  thereby reducing the height of the connector above the circuit board  4  and forming a low profile connector configuration as shown in FIG.  4 . Furthermore, forming boardlocks on the second transverse extensions  141  rather than on the bottom section  12  of the shielding casing  1  allows the connector to be entirely enclosed by the shielding casing  1  thereby more fully eliminating electromagnetic interference. 
     Although the present invention has been described with reference to the preferred embodiment, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.