Abstract:
An all metal shell BNC electrical connector provides a metal shell with at least two locating holes and at least one of the locating holes receives insulators, a spring plate and a conductive plate. A metal jacket urges a resistance against the conductive plate from a receiving groove defined on the shell wall

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a connector for a signal transmission wire, and particularly to a BNC connector, which is associated with a printed circuit board and provides an all metal shell.  
           [0003]    2. Description of Related Art  
           [0004]    The signal transmission between electric apparatuses is performed by way of a connector associated with transmission wires. The present inventor has invented a connector entitled “DUAL TYPE BNC connector (ADDITION 1)” published in Taiwanese Patent Official Gazette discloses a dual type BNC connector with metal shell. The dual type BNC connector is joined to a circuit board for connecting with another connector. Referring to FIG. 1, the dual type BNC connector has a metal shell  10  and the shell  10  is provided with two parallel locating holes  11 ,  12  for engaging with two BNC plugs  13 ,  14 . The shell  10  has an insertion part  15  to be inserted into joining holes of the circuit board. The BNC connectors  13 ,  14  have lead wires  16 ,  17  thereof exposing at the rear end  18  of the shell  10 .  
           [0005]    In order to enhance the quality of signal transmitted by the BNC connector, the inventor has discovered during conducting investigation that the quality of signal transmitted by the BNC can be enhanced if the shell  10  at the rear end thereof is attached with a metal cover. Further, the output end of the connector still emits electromagnetic wave to interfere neighboring electronic electromagnetic signals in case of the connector not connecting other connectors. In order to solve the problem of electromagnetic wave interference, the U.S. Pat. No. 5,387,116 owned by the present inventor has disclosed an auto termination BNC T adapter. However, the T adapter is not possible to be inserted into the printed circuit board due to no insert part being provided so that it is not suitable for being a connector engaging with the printed circuit board in case of other signal connectors being connected to the printed circuit board. In order to improve the connector disclosed in the U.S. Pat. No. 5,387,116, the present invention has developed an all metal shell BNC electric connector, which is possible to be inserted into a socket on the printed circuit board directly.  
         SUMMARY OF THE INVENTION  
         [0006]    An object of the present invention is to provide an auto termination PCB mount connector, which has advantages such as simple construct, being easily set up, a lower cost, and conveniently engaging with the printed circuit board.  
           [0007]    Another object of the present invention is to an auto termination PCB mount connector, which is possible to reduce the interference resulting from the electromagnetic wave.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The present invention can be more fully understood by reference to the following description and accompanying drawing, in which:  
         [0009]    [0009]FIG. 1 is a sectional view of a conventional dual type BNC connector;  
         [0010]    [0010]FIG. 2 is an exploded perspective view of a BNC connector according to the present invention;  
         [0011]    [0011]FIG. 3 is a sectional view of the BNC connector shown in FIG. 2;  
         [0012]    [0012]FIG. 4 is an exploded perspective view of a BNC connector according to the present invention in another embodiment thereof;  
         [0013]    [0013]FIG. 5 is a sectional view of a BNC connector according to the present invention in another embodiment thereof;  
         [0014]    [0014]FIG. 6 is an assembled perspective view of the BNC connector shown in FIG. 2;  
         [0015]    [0015]FIG. 7 is an assembled perspective view of the BNC connector shown in FIG. 4;  
         [0016]    [0016]FIG. 8 is a perspective view of a further embodiment of BNC connector according to the present invention;  
         [0017]    [0017]FIG. 9 is perspective view of a further embodiment of BNC connector according to the present invention;  
         [0018]    [0018]FIG. 10 is a sectional view of an auto termination PCB mount connector according to the present invention in a tenth embodiment thereof;  
         [0019]    [0019]FIG. 11 is a sectional view of a BNC plug with automatic circuit structure;  
         [0020]    [0020]FIG. 12 is a sectional view of a further embodiment of BNC connector according to the present invention;  
         [0021]    [0021]FIG. 13 is a sectional view of a further embodiment of BNC connector according to the present invention;  
         [0022]    [0022]FIG. 14 is a sectional view of a further embodiment of BNC connector according to the present invention;  
         [0023]    [0023]FIG. 15 is a sectional view of a further embodiment of BNC connector according to the present invention;  
         [0024]    [0024]FIG. 16 is a sectional view of a further embodiment of BNC connector according to the present invention;  
         [0025]    [0025]FIG. 17 is a sectional view of a further embodiment of BNC connector according to the present invention;  
         [0026]    [0026]FIG. 18 is a sectional view of a further embodiment of BNC connector according to the present invention; and  
         [0027]    [0027]FIG. 19 is a sectional view of a further embodiment of BNC connector according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    Referring to FIGS. 2 and 3, a BNC connector of the present invention is different from the conventional dual type BNC connector shown in FIG. 1 in that the BNC connector of the present invention has a metal shell  20  with engaging holes  211  at a rear end  21  thereof for joining with a metal cover  22  by way of screws  212  so that the a BNC plug  23  with lead wires  231  at the rear end thereof is in a space enclosed by the metal shell  20  and the metal cover  22 . In this way, the power loss can be reduced during the BNC plug transmitting signals and it is possible to refuse electromagnetic waves emitted from other electronic components outside the BNC connector interfering the signals transmitted by the BNC plug such that signal quality transmitted by the BNC plug can be enhanced effectively. The shell  20  at a direction perpendicular to the BNC plug  23  has double-inverted hook-shaped contact pins  24  for the BNC connector being inserted into the circuit board.  
         [0029]    Referring to FIG. 4, another embodiment of the BNC connector according to the present invention is similar to the BNC connector shown in FIG. 2 and the only difference is that an projection  251  is provided to extend from the metal cover  25  for being inserted into the engaging holes at the bottom of the shell  20  directly instead of screws  212  in FIG. 2.  
         [0030]    Referring to FIG. 5, a further embodiment of the BNC connector according to the present invention provides a structure of integral lead wire  233  and terminals  234  instead of individual lead wires  231  and terminals  232  shown in FIG. 3. The lead wire  233  is tube shaped piece made of a sheet plate.  
         [0031]    Referring to FIGS. 6 and 7, the BNC plug with the lead wire at the rear end thereof arranged in the present invention is disposed in a space enclosed by the metal shell  20  and the metal cover  22  or the metal cover  25  to enhance the quality of signal transmitted by the BNC plug.  
         [0032]    Referring to FIG. 8, a further embodiment of the BNC connector according to the present invention is arranged to have a plurality of lined up locating holes  31  on the shell  30  and each of the locating holes  31  is associated with the BNC plug  32  respectively.  
         [0033]    Referring to FIG. 9, a further embodiment of the BNC connector according to the present invention is arranged to have multiple lines of locating holes  41  on the shell  40  and each of the locating holes  41  is associated with the BNC plug  42  respectively.  
         [0034]    Referring to FIG. 10, The BNC connector of the present invention can be a connector with automatic termination. The BNC plug with automatic termination has a structure including a rear insulator  60 , a front insulator  61 , a spring plate  70 , a packing ring  71 , a conductive plate  72 , a resistor  73 , an isolator  74  and a metal jacket  75  arranged in the metal shell  50 . The metal shell  50  has a shell wall  51  with a locating hole  52  passing through both ends at the inner side thereof. The locating hole  52  is divided into a large hole section  521 , a middle hole section  522  and a small hole section  523 , sequentially. The shell wall  51  at a part thereof adjacent to the small hole section  523  provides a receiving groove  511  and the receiving groove  511  communicates with a small hole  512  passing through the shell wall  51 . The shell wall  51  at the outer side thereof is joined to a metal fixing element  53  vertically and the shell  50  at the rear end thereof is attached with a metal cover  54 . The rear insulator  60  has a first guide groove  601 , a second guide groove  602  and a hole  603  with an end thereof having an engaging section  604 , which has an outer diameter larger than the rest part of the rear insulator  60 . The hole  603  communicates with the second guide groove  602 . The front isolator  61  has a pierced hole  611  and a guide groove  612 . The spring plate  70  has a tail section  701 , a slant section  702  and a touch section  703  with the slant section  702  extending a contact plate  704  and the touch section  703  having an arc bend.  
         [0035]    In case of the BNC plug with automatic termination being mounted, the spring plate  70  at the tail section  701  thereof passes through the first guide groove  601  of the rear insulator  60  and extends outward and the conductive plate  72  at an end thereof is arranged to fit with the second guide groove  602 . Then, both the slant section  702  and the touch section  703  of the spring plate  70  are received in the pierced hole  611  of the front insulator  61 , and the other end of the conductive plate  60  is arranged to fit with the guide groove  612  of the front insulator  61 . Next, the rear insulator  60  and the front insulator  61  are inserted into the shell  50  such that an end of the rear insulator  60  can extend through the small hole section  523  and it allows the hole  603  to communicate with the small hole  512  of the shell wall  51  and the engaging section  604  can fit with a lateral side of the middle hole section  522 . The front insulator  61  at an end thereof fits with the middle hole section  522  against the engaging section  604 , and the other end thereof is received in the large hole section  521 . Further, the packing ring  71  is stuffed between the outer wall of the front insulator  61  and the inner wall surface of the shell wall  51  to fix the rear insulator  60  and front insulator  61  in the shell  50 . The resistor  73  is inserted into the hole  603  of the rear insulator  60  through the small hole  512  and the insulator  74  with a central through hole fitting with the resistor  73  so as to be disposed in the small hole  512  and keep untouched with the shell wall  51 . Finally, the metal jacket  75  is pressed tightly toward the inner side of the shell  50  from the receiving groove  511  of the shell wall  51  to urge the resistor  73  against the conductive plate  72 .  
         [0036]    While the BNC plug with automatic termination of present invention is in use, the spring plate  70  has the contact plate  704  to keep contact with the conductive plate  72  in a normal state. If an inserting end of any other connector is inserted, the spring plate  70  at the touch section  703  thereof may contact the inserting end right away and the inserting end may prop up both the touch section  703  and the contact plate  704  to keep the contact plate  704  separating from the conductive plate  72 . As soon as the inserting end of the other connector is detached, the contact plate  704  of spring plate  70  may spring back to the original position thereof to contact the conductive plate  72  again such that a signal output from the spring plate  70  may be sent back to the grounded line of the printed circuit board through the conductive plate  72 , the resistor  73 , the metal jacket  75 , the metal shell  50 , and the metal fixing element  53  so as to constitute a loop automatically. Due to the resistor  73 , the loop can provide a better wave filtering function. In this way, the interference problem of the electromagnetic wave resulting from the output signal of the spring plate  70  can be reduced and a less output power loss can be lowered down too.  
         [0037]    Referring to FIG. 11, a further embodiment of the BNC connector according to the present invention provides a shell  80  with two locating holes  801 ,  802 . The locating hole  801  is associated with a BNC plug  803  without automatic termination and another locating hole  802  with the shell wall  804  at the lateral side thereof is associated with a BNC plug  805  having automatic termination as the case shown in FIG. 10. The shell  80  at the rear end thereof is associated with a metal cover  806 .  
         [0038]    Referring to FIG. 12, a further embodiment of the BNC connector according to the present invention provides two locating holes  811  and each locating hole  811  with the shell wall  812  at the lateral side thereof is associated with a BNC plug  813  having automatic termination as the case shown in FIG. 10. The shell  81  at the rear end thereof is associated with a metal cover  814 .  
         [0039]    Referring to FIGS. 13, 14 and  15 , further embodiments of the BNC connector according to the present invention provide two, six and eight locating holes on the shell respectively and each locating hole is joined to a BNC plug without automatic termination or a BNC plug with automatic termination.  
         [0040]    Referring to FIGS. 16 and 17, two further embodiments of the BNC connector according to the present invention provide the same structures as the BNC connectors shown in FIGS. 11 and 12 except no design of metal covers.  
         [0041]    Referring to FIGS. 18 and 19, two further embodiments of the BNC connector provide structures the same as the BNC connectors shown in FIGS. 16 and 17 except the shells  82 ,  83  at the outer sides thereof being covered an insulation piece  821 ,  831  on the rear sections thereof.  
         [0042]    It is appreciated that the present invention provides a BNC connector with automatic termination and a rear metal cover, which can be inserted into the a printed circuit board with less parts and easy assembly, so that it is possible to reduce the production cost. Furthermore, the circuit can provide a better wave filtering function by way of the resistance to lower down chance of being interfered by the electromagnetic wave and reduce loss of power output.  
         [0043]    While the invention has been described with reference to preferred embodiments thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention, which is defined by the appended claims.