Abstract:
A high density electrical interconnect is disclosed that uses a bayonet action to mate a plug having a plurality of contacts to receptacle having a plurality of spring contacts. The plurality of contacts may be a plurality of pin contacts, printed circuit board traces, or flexible film contacts. The spring contacts are preloaded to reduce the insertion force required to mate the plug and receptacle.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to electrical connectors, and more particularly, to a coupling mechanism and contact configuration for an electrical connector having a high density of contacts. 
       BACKGROUND OF THE INVENTION 
       [0002]    High density electrical connectors having a large number of contacts are used in a wide variety of applications. High density connectors are desirable because they reduce connector sizes, thereby requiring less overall space and eliminating excess bulk. This is highly advantageous in many applications, such as medical, aircraft and aerospace applications, where cost, space and weight savings are at a premium. A typical type of electrical connector assembly of the character described is a circular connector assembly which includes a male plug connector and a female receptacle connector. A coupling ring is rotatably mounted about one of the connectors for rotatably coupling the connectors in mating interengagement. The coupling system may utilize, for example, bayonet type or screw-thread type shells. Small high density contacts interconnect when the plug and receptacle connectors are rotatably mated. 
         [0003]    As the density and number of electrical contacts used in such applications increases, problems arise upon mating of the connectors due to the high insertion force required to mate the high number of contacts. The high insertion forces required to mate the high number of contacts, especially in environments where the connectors are not easily accessed, or in a blind mating condition, or where the connectors must be cycled repeatedly, or where cost must keep the design complexity of the connector to a minimum, has presented a problem for current connector design. Therefore, there is a need for an improved high density connector having lower required insertion force during mating. 
       SUMMARY OF THE INVENTION 
       [0004]    In an exemplary embodiment of the invention, an electrical connector is disclosed that includes a plug and a receptacle. The plug includes a plug housing having a plug contact sub-assembly support structure, at least one plug contact sub-assembly disposed within the plug contact sub-assembly support structure, a plug housing shell attached to a rear portion of the plug housing and disposed around the plug contact sub-assembly support structure, and a plurality of contacts received and supported in the plug contact sub-assembly. The receptacle includes a receptacle housing having a receptacle contact sub-assembly support structure, a receptacle contact sub-assembly disposed within the receptacle contact sub-assembly support structure, a receptacle housing shell attached to a rear portion of the receptacle housing, and a plurality of spring contacts received and supported in the receptacle contact sub-assembly. The plurality of spring contacts may be preloaded with an opening force. 
         [0005]    The plug may further include bayonet slots disposed upon an outer surface of the plug housing, and the receptacle may further include a coupling ring disposed around the receptacle housing. The bayonet slots and coupling ring are configured to axially draw the plug into a fully mated position with the receptacle when the coupling ring is rotated. 
         [0006]    Further aspects of the method and system are disclosed herein. The features as discussed above, as well as other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of an exemplary mated electrical connector according to the invention. 
           [0008]      FIG. 2  is a perspective view of the unmated electrical connector of  FIG. 1 . 
           [0009]      FIG. 3  is a perspective view of an exemplary embodiment of plug according to the invention. 
           [0010]      FIG. 4  is an exploded view of the plug of  FIG. 3 . 
           [0011]      FIG. 5  is a rear view of the plug housing of the plug of  FIG. 4 . 
           [0012]      FIG. 6  is a perspective view of the plug contact sub-assembly of  FIG. 4 . 
           [0013]      FIG. 7  is an exploded view of the plug contact sub-assembly of  FIG. 6 . 
           [0014]      FIG. 8  is a perspective view of another exemplary plug contact sub-assembly according to the invention. 
           [0015]      FIG. 8A  is an exploded view of the contact sub-assembly of  FIG. 8 . 
           [0016]      FIG. 9  is a rear view on another exemplary plug housing according to the invention. 
           [0017]      FIG. 10  is a perspective view of another exemplary plug contact sub-assembly according to the invention. 
           [0018]      FIG. 10A  is an exploded view of the plug contact sub-assembly of  FIG. 10 . 
           [0019]      FIG. 10B  is a perspective view of a flexible film, shown in a flat state, used in the plug contact sub-assembly of  FIG. 10 . 
           [0020]      FIG. 11  is a front perspective view of an exemplary receptacle according to the invention. 
           [0021]      FIG. 12  is an exploded view of the receptacle of  FIG. 11 . 
           [0022]      FIG. 13  is a rear view of an exemplary receptacle housing according to the invention. 
           [0023]      FIG. 14A  is a perspective view of an exemplary spring contact sub-assembly according to the invention. 
           [0024]      FIG. 14B  is an exploded view of the spring contact sub-assembly of  FIG. 14A . 
           [0025]      FIG. 14C  is a cross-sectional view of  FIG. 14A  taken along line  14 C- 14 C. 
           [0026]      FIG. 14D  is an expanded view of a portion of  FIG. 14C  with a plug contact inserted. 
           [0027]      FIG. 15  is a cross sectional view of the mated connector of  FIG. 1  taken along line  15 - 15 . 
       
    
    
       [0028]    Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. 
         [0030]    An exemplary embodiment of an electrical connector  100  according to the present invention is shown in  FIGS. 1 and 2 . The electrical connector  100  is shown mated in  FIG. 1  and unmated in  FIG. 2 . The electrical connector  100  includes a plug  102  and a receptacle  104 . The plug  102  and receptacle  104  are configured to be releasably mated, as will be described in further detail below. The plug  102  and receptacle  104  are mechanically coupled by the use of a coupling ring  108  carried by the receptacle  104 . The plug  102  includes a plug housing  110  having an outer surface  111 . The outer surface  111  has bayonet slots  112  (two additional bayonet slots are equally radially spaced, but not shown, on the housing  110 ) disposed thereupon for receiving corresponding bayonet pins  113  ( FIG. 12 ) disposed within the coupling ring  108  as would be appreciated by one of ordinary skill in the art. In this exemplary embodiment, the housing  110  has three radially disposed bayonet slots  112  and corresponding bayonet pins  113 , however, other embodiments may use one or more bayonet slots  112  and corresponding bayonet pins  113  to secure the plug  102  and receptacle  104 . The plug  102  is drawn axially into fully mated engagement with the receptacle  104  as shown in  FIG. 2  by engagement between the bayonet pins  113  of the coupling ring  108  and the bayonet slots  112  of the plug  102  as the coupling ring  108  is rotated. In other embodiments, other locking and/or camming mechanisms may be used in place of the coupling ring  108  and bayonet slots  112  to secure and/or assist in the mating of the plug  102  and receptacle  104 . The non-conductive components of the electrical connector may be molded from any thermoplastic or similar material as would be appreciated by one of ordinary skill in the art. Additionally, any conductive component may be formed from any conductive material as would be appreciated by one of ordinary skill in the art. 
         [0031]      FIGS. 3 and 4  show plug  102  in greater detail. The plug  102  includes a plug housing  110 , a plug housing shell  114 , a flexible cable connector  116 , and at least one plug contact sub-assembly  144 . The plug housing shell  114  includes a first plug housing shell portion  114   a  and a second plug housing shell portion  114   b.  The second plug housing shell portion  114   b  includes posts  120  and the first plug housing shell portion  114   a  includes corresponding openings (not shown) for securing the second plug housing shell portion  114   b  to the first plug housing shell portion  114   a.  In alternative embodiments, the first plug housing shell portion  114   a  and the second plug housing shell portion  114   b  may be provided with any corresponding combinations of tabs, slots, pins, screws, openings or other similar fasteners to secure the first plug housing shell portion  1   14   a  and the second plug housing shell portion  1   14   b  together as would be appreciated by one of ordinary skill in the art. In another embodiment, the plug housing shell  114  may be a single molded structure. 
         [0032]    The plug housing shell  114  further includes an outer surface  122  and an inner surface  124 . The plug housing shell  114  also includes a front engaging portion  126  having tabs  128  disposed thereupon (a similar tab  128  is present but not shown on the opposite side of the plug housing shell  114 ). The tabs  128  engage corresponding slots  130  (a similar slot  130  is present but not shown on the opposite side of the plug housing  110 ) in the plug housing  110  to secure the plug shell housing  114  to the plug housing  110 . In alternative embodiments, the plug housing shell  114  and the plug housing  110  may be provided with any corresponding combinations of tabs, slots, pins, openings or other similar fasteners to secure the plug housing  110  and the plug housing shell  114  together as would be appreciated by one of ordinary skill in the art. Furthermore, in other embodiments, the engaging portion  126  may be provided over the plug housing  110  instead of being received within the plug housing  110  as in the exemplary embodiment. 
         [0033]    The plug housing shell  114  further includes a rear opening  132  for receiving and securing flexible cable connector  116 . In this exemplary embodiment, the flexible cable connector  116  includes a generally circular groove  134  that is secured in the rear opening  132  when the first shell portion  114   a  and the second shell portion  114   b  are assembled to each other. The flexible cable connector  116  may be of any length, and may be terminated and/or connected to another electrical device or connection (not shown) as would be appreciated by one of ordinary skill in the art. In another embodiment, the flexible cable connector  116  and the plug housing shell  114  may be otherwise configured with clamps, pins, slots or other fasteners to secure the flexible cable  116  to the plug housing shell  114 . Additionally, while the rear opening  132  and groove  134  are shown having a generally circular geometry, it should be appreciated by one of ordinary skill in the art that the rear opening  132  and groove  134  may have any shape, including, but not limited to square, rectangular, and oval. In addition, flexible cable connector  116  may include a keying feature  137 . In operation, a cable or wire having a plurality of conductors (not shown) would be provided through the flexible cable connector  116  and terminated to pads, traces, the plurality of contacts  150  ( FIG. 3 ) and/or other termination features on a surface including a top surface, bottom surface and/or edge surface as would be appreciated by one of ordinary skill in the art. 
         [0034]    As can be further seen in  FIGS. 3 and 4 , the plug housing  110  further includes a front plug housing surface  134  having contact assembly slots  136  therethrough, and a contact sub-assembly support structure  138 . A rear view of the plug housing  110  showing greater detail of the contact assembly support structure  138  is shown in  FIG. 5 . As can be seen in  FIG. 5 , the contact assembly support structure  138  includes guide rails  140  and slot supports  142  configured to receive and support plug contact sub-assemblies  144 . In this exemplary embodiment, the plug  102  contains four contact sub-assemblies  144 , and the contact assembly support structure  138  is configured with guide rails  140  and a slot support  142  to support each contact sub-assembly  144 . In another embodiment, the plug housing  110  may be provided with one or more slots  136 , with guide rails  140  and slot supports  142  to receive and support a corresponding number of slots  136 . In yet another embodiment, not all slots  136 , guide rails, and slot supports  142  may necessarily support a sub-assembly  144 , or in other words, be left open. In another embodiment, interior surfaces  115  of the plug housing  110 , including the front plug housing surface  134  and the contact assembly support structure  138  may be plated with an electrically shielding material. 
         [0035]    A plug contact sub-assembly  144  is shown in greater detail in  FIGS. 6 and 7 . The plug contact sub-assembly  144  includes a plug sub-assembly base  146 , a plug contact support housing  148 , a plurality of plug contacts  150 , and a plug contact alignment spacer  152 . In this exemplary embodiment, the plurality of plug contacts  150  are a plurality of stitched contacts, however, in other embodiments of the invention described below, other contacts which may be used in the invention as described. The plug sub-assembly base  146  may be a printed circuit board. The plug contact support housing  148  includes a plurality of openings  154  and a plurality of micro-channels  156  for receiving and supporting the plurality of contacts  150 , respectively. The plurality of plug contacts  150  are further received through another plurality of openings  158  in the plug contact alignment spacer  152  prior to the plurality of plug contacts  150  being received through yet another plurality of openings  160  in the plug sub-assembly base  146 . The plug contact alignment spacer  152  serves as an alignment aid for receiving and retaining the plurality of plug contacts  150  in the plug sub-assembly base  146 . In another embodiment, the plug contact alignment spacer  152  may be formed by overmolding the plug contacts  150  to form a plug contact alignment spacer assembly (not shown) including the plurality of contacts  150 . After the plurality of plug contacts  150  are received through the plurality of openings in the plug sub-assembly base  146 , the plurality of plug contacts  150  are terminated to pads, traces or other conductive paths (not shown) of the plug sub-assembly base  146 . The conductive paths may be present on a top surface  162 , a bottom surface (not shown), and interior surface (not shown), an edge surface  164 , or any combination thereof of the plug sub-assembly base  146 . A plurality of conductors (not shown) provided to the plug  102  through the flexible cable connector  116  are correspondingly terminated to the conductive paths and/or plurality of contacts  150  as would be appreciated by one of ordinary skill in the art. 
         [0036]      FIGS. 8 and 8A  show another exemplary plug contact sub-assembly  800  that may be used with the plug  102 . Plug contact sub-assembly  800  includes a printed circuit board (PCB)  810  and an optional overmold  830 . The PCB includes a plurality of contacts  820  disposed on a top surface  825 . The plurality of contacts  820  are terminated to pads, traces or other conductive paths (not shown) of the PCB  810 . The conductive paths may be present on a top surface  825 , a bottom surface (not shown), and interior surface (not shown), an edge surface  812 , or any combination thereof. A plurality of conductors (not shown) provided to the plug  102  through the flexible cable connector  116  are correspondingly terminated to the conductive paths and/or plurality of contacts  820  as would be appreciated by one of ordinary skill in the art. The PCB  810  includes through holes  827  for receiving projections  828  of the overmold  830  to attach to the overmold  830  to the PCB  810 . Overmold  830  protects the plurality of spring contacts  200  ( FIG. 14B ) from damage and wear during the mating and unmating of the plug  102  and the receptacle  104 . 
         [0037]    In order to use the plug contact sub-assembly, the plug housing  110  is modified by replacing the plug contact assembly support structure  138  ( FIG. 5 ) with another plug contact assembly support structure  905  as shown in  FIG. 9 . As can be seen in  FIG. 9 , the plug contact assembly support structure  905  includes a plurality of support walls  910  and insertion slots  915 . Support walls  910  include retention tabs  930  for supporting and securing plug contact sub-assembly  800  ( FIG. 8 ). In another embodiment, the plug housing  110  may be provided with one or more insertion slots  915  and corresponding support walls  910  corresponding to the number of plug contact sub-assemblies  800  used. 
         [0038]      FIGS. 10 and 10A  show yet another alternative plug contact sub-assembly  1000 . Plug contact sub-assembly  1000  includes a support board  1010  and a flexible film contact assembly  1020 . Flexible film contact assembly  1020  includes a first surface  1022  having a plurality of contacts  1040  disposed thereupon. The flexible film contact assembly  1020  also includes a second surface (not shown) opposite side surface  1022 . The flexible film contact assembly  1020  further includes a plurality of conductive traces (not shown) providing an electrical path between the plurality of contacts  1040  and a plurality of contact pads  1050 . The plurality of conductive traces may be disposed on the first surface  1022 , second surface, between the first surface and the second surface, or any combination thereof. The plug contact sub-assembly  1000  is formed by applying the flexible film contact assembly  1020  to the support board  1010 . The flexible film contact assembly  1020  may be applied to the support board  1010  by gluing or other known fastening methods. The plug contact sub-assembly  1000  is supported in the plug housing  110  by the plug contact assembly support structure  910  shown in  FIG. 9 . 
         [0039]      FIGS. 11 and 12  show receptacle  102  in greater detail. Receptacle  102  includes a receptacle housing gasket  109 , a receptacle housing  162 , a coupling ring  108 , a receptacle housing shell  164 , a flexible cable connector  166 , and at least one receptacle contact sub-assembly  168 . The receptacle housing gasket  109  provides an environmental seal between the receptacle  104  and the plug  102 . The receptacle housing gasket  109  may be formed of any elastomeric material as would be appreciated by one of ordinary skill in the art. In another embodiment, when an electrical shield material is used as discussed below, the receptacle housing gasket may be formed by a conductive elastomeric material to provide both electrical conduction/EMI protection and environmental seal, or may be formed of a compliant metal if an environmental seal is not required. 
         [0040]    In addition, in an another embodiment when the receptacle shell  164  and/or the receptacle housing  162  is provided with a plated electrical shield coating (not shown) as discussed in the additional embodiments discussed below, the plug housing gasket  109  can provide an electrical pathway between the receptacle shielding and the plug shielding. 
         [0041]    The receptacle housing shell  164  includes a first receptacle housing shell portion  164   a  and a second receptacle housing shell portion  164   b.  The second receptacle housing shell portion  164   b  includes tabs  170  and openings  172  and the first receptacle housing shell portion  164   a  includes corresponding slots (not shown) and pins (not shown) for securing the second receptacle housing shell portion  164   b  and the first receptacle housing shell portion  164   a  together. In alternative embodiments, the first receptacle housing shell portion  164   a  and the second receptacle housing shell portion  164   b  may be provided with any corresponding combinations of tabs, slots, pins, screws, openings or other similar fasteners to secure the first receptacle housing shell portion  164   a  and the second receptacle housing shell portion  164   b  together as would be appreciated by one of ordinary skill in the art. In another embodiment, the receptacle housing shell  164  may be a single structure. 
         [0042]    The receptacle housing shell  164  further includes an outer surface  174  and an inner surface  176 . Receptacle contact sub-assembly support surfaces  177  are disposed on the inner surface  176 . The receptacle housing shell  164  also includes a front engaging portion  178  having tabs  180  disposed thereupon (a similar tab  180  is present but not shown on the opposite side of the receptacle housing shell  164 ). The tabs  180  engage corresponding slots  182  (a similar slot  182  is present but not shown on the opposite side of the receptacle housing  162 ) in the receptacle housing  162  to secure the receptacle shell housing  164  to the receptacle housing  162 . In alternative embodiments, the receptacle housing shell  164  and the receptacle housing  162  may be provided with any corresponding combinations of tabs, slots, pins, openings or other similar fasteners to secure the receptacle housing  162  and the receptacle shell housing  164  together as would be appreciated by one of ordinary skill in the art. Furthermore, in other embodiments, the engaging portion  178  may be provided over the receptacle housing  162  instead of being received within the receptacle housing  162  as in the exemplary embodiment. 
         [0043]    The receptacle housing shell  164  further includes a rear opening  184  for receiving and securing flexible cable connector  166 . In this exemplary embodiment, flexible cable connector  166  includes a generally circular groove  186  that is secured in the rear opening  184  when the first receptacle housing shell portion  164   a  and the second receptacle housing shell portion  164   b  are assembled to each other. In other embodiments, the flexible cable connector  166  and the plug housing shell  164  may be otherwise configured with clamps, pins, slots or other fasteners to secure the flexible cable connector  166  to the receptacle housing shell  164 . Additionally, while the rear opening  184  and groove  186  are shown having a generally circular geometry, it should be appreciated by one of ordinary skill in the art that the rear opening  184  and groove  186  may have any shape, including, but not limited to square, rectangular, and oval. In another embodiment, groove  186  may contain a keying feature (not shown), with the rear opening  184  having a corresponding mating keying feature (not shown). In operation, a cable or wire having a plurality of conductors (not shown) would be provided through the flexible cable connector  166  and terminated to the plurality of spring contacts  200  ( FIG. 14A ) and/or other termination features as described below. 
         [0044]    As can be further seen in  FIGS. 11 and 12 , the receptacle housing  162  further includes a front receptacle housing surface  190  having spring contact assembly slots  192  therethrough. A rear view of the receptacle housing  162  showing the spring contact assembly slots  192  is shown in  FIG. 13 . As can be seen in  FIG. 13 , the spring contact assembly support slots  192  includes guide rails  194  configured to receive and support a spring contact sub-assembly  168 . In this exemplary embodiment, the receptacle  102  includes four spring contact sub-assemblies  188 . In another embodiment, the receptacle housing  162  may be provided with one or more slots  192  to receive and support a corresponding number of spring contact sub-assemblies  168 . In yet another embodiment, not all slots  192  may necessarily support a spring contact sub-assembly  168 , or in other words, be left open. 
         [0045]    A spring contact sub-assembly  168  is shown in greater detail in  FIGS. 14A ,  14 B and  14 C. The spring contact sub-assembly  168  includes a sub-assembly base  196 , a contact support housing  198 , a plurality of spring contacts  200 , and a contact alignment spacer  202 . The spring contact sub-assembly  168  may include an optional spring contact assembler  204 . The sub-assembly base  196  includes a top surface  212 , a bottom surface (not shown), and an edge surface  216 . In another embodiment, the spring contact assembler  204  may also be overmolded with the plurality of spring contacts  200 . The contact support housing  198  includes a retaining surface  206  ( FIG. 14D ) for receiving and supporting the plurality of spring contacts  200  in a preloaded configuration. The retaining surface  206  forces the plurality of spring contacts  200  open beyond the spring contacts natural free state but not to the total amount of travel when mated with the corresponding plurality of plug contacts  150 . The plurality of spring contacts  200  are further received through a plurality of openings  208  in the contact alignment spacer  202  prior to the plurality of spring contacts  200  being received through yet another plurality of openings  210  in the sub-assembly base  196 . The contact alignment spacer  202  serves as an alignment aid for receiving the plurality of spring contacts  200  in the sub-assembly base  196 . After the plurality of spring contacts  200  are received through the plurality of openings  210  in the sub-assembly base  196 , the plurality of spring contacts  200  are terminated to traces, contact pads, conductive paths (not shown), and/or any combination thereof provided on the top surface  212 , bottom surface (not shown) and/or edge surface  216  and/or any combination thereof of the sub-assembly base  196 . A plurality of conductors (not shown), provided to the receptacle  104  through flexible cable connector  166 , would correspondingly be terminated to the traces, contact pads, conductive paths, the plurality of spring contacts  200  or any combination thereof as would be appreciated by one of ordinary skill in the art. 
         [0046]      FIG. 14D  shows an enlarged view of a portion of  FIG. 14C  including a contact  150  inserted therein. As can be seen in  FIG. 14D , the spring contact  200  has been expanded by receiving contact  150  so as to disengage the spring contact  200  from the retaining surface  206 , thereby assuring a positive electrical connection between the contact  150  and spring contact  200 . 
         [0047]    A cross sectional view  4 - 4  of the mated connector  100  of  FIG. 1  taken along line  15 - 15  is shown in  FIG. 15 . As can be seen in  FIG. 15 , when the plug  102  and receptacle  104  are mated, contacts  150  are mated to corresponding spring contacts  200 . 
         [0048]    While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.