Abstract:
An electrical connector system includes mating pin and socket connectors each designed for increased contact density to improve performance of high-speed data transfer. The connectors include features for retaining a plurality of pin or socket contacts in a ganged, co-aligned configuration and for shielding groups of contacts from one another to reduce interference and crosstalk. The connectors further include features for providing strain relief to the internal wires and/or cables. One of the connectors may include a plug insert with cantilevered fingers extending therefrom that contact a conductive surface of the mating connector to provide a mechanical connection and a low-impedance pathway between the mating connectors for grounding and shielding. The connectors are designed to be readily assembled and disassembled for repair or rework without the use of special tools.

Description:
RELATED APPLICATION DATA 
     This application is a nonprovisional of and claims the benefit under 35 U.S.C. §119(e) from U.S. Provisional Patent Application No. 61/719,877, filed Oct. 29, 2012, and titled ELECTRICAL CONNECTOR FOR RETAINING CONTACTS, which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The field of this disclosure relates to electrical connectors and, in particular, to an electrical connector system with increased contact density and enhanced shielding devices to reduce interference and crosstalk amongst different wires of the cable and different conductors of the connector system. 
     BACKGROUND 
     Increasingly, electronic devices transmit and receive high-frequency electrical signals representing digital data. High-speed data transmission, such as so-called Ultra High-Speed (UHS) data transmission involves the transmission of data between electronic devices at rates of 1 to 10 gigabits per second using signal frequencies of 100 MHz to 500 MHz. There is a desire for future high-speed data transmission at even faster rates and at even higher frequencies. For example, UHS data transmission may be achieved over 1000BASE-T Ethernet networks using category 5, 5E, 6 or 6A cables. Such high-speed digital data networks are not confined to terrestrial applications, especially as high-speed electronics are developed for aerospace and other suitable applications. 
     High-speed digital data transmission is facilitated by a data transmission system with a relatively high signal to noise ratio. For example, one system includes a 1000BASE-T Ethernet network that includes category 5, 5E, 6 or 6A cables. Cables in such a system are designed to propagate data signals without generating or introducing appreciable noise, and are terminated by electrical connectors at either end to either connect cables together, or to connect cables to electronic devices. Electrical connectors commonly used for terrestrial applications, such as the RJ-45 style connector, have proved to be less than suitable for aerospace and other applications. In aerospace and other applications, electrical connectors are subjected to a variety of harsh environmental conditions, such as the presence of moisture, vibrations and mechanical shock, relatively high amounts of external electrical and magnetic interference, and pressure changes, all of which can detrimentally affect an electrical connector&#39;s performance, that is, its ability to transmit data signals while maintaining a relatively high signal to noise ratio. Common electrical connectors for aerospace and other suitable applications, such as the Quadrax-style connector, may work for data transfer rates less than 1 gigabit per second, but tend to exhibit, induce, generate or introduce excessive noise during high-speed data transmission at rates faster than 1 gigabit per second. 
     Because degraded performance of an electrical connector adversely affects the ability of a system to transfer data at high rates, the present inventor has recognized a need for a robust electrical connector capable of facilitating high-speed data transfer in aerospace and other suitable applications, for example, in aircraft electronic systems having performance criteria meeting gigabit data transfer standards such as 1000BASE-T. The present inventor has also recognized a need for an improved electrical connector with a streamlined design allowing for increased contact density within the connector housing and enhanced shielding capabilities to reduce interference and crosstalk. The present inventor has also recognized a need for such a connector that can be easily assembled and disassembled for repair and rework. 
     Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an electrical connector according to one embodiment. 
         FIG. 2  is an exploded view of the electrical connector of  FIG. 1 . 
         FIG. 3  is a perspective view of a plug insert of the electrical connector of  FIG. 1 . 
         FIG. 4  is a rear perspective view of a spacer of the electrical connector of  FIG. 1   
         FIG. 5  is a perspective view of an electrical connector for mating with the electrical connector of  FIG. 1 . 
         FIG. 6  is an exploded view of the electrical connector of  FIG. 5 . 
         FIG. 7  is a perspective view of a plug insert of the electrical connector of  FIG. 5 . 
         FIG. 8  is a cross-sectional view illustrating a latch mechanism of the electrical connector of  FIG. 1 . 
         FIG. 9  is a perspective view of an electrical connector according to another embodiment. 
         FIG. 10  is an exploded view of the electrical connector of  FIG. 9 . 
         FIG. 11  is a cross-sectional view of the electrical connector of  FIG. 9  illustrating an internal shell-retention mechanism. 
         FIG. 12  is a perspective view of an electrical connector for mating with the electrical connector of  FIG. 9 . 
         FIG. 13  is an exploded view of the electrical connector of  FIG. 9 . 
         FIGS. 14-15  are perspective views of an electrical connector according to another embodiment. 
         FIG. 16  is an exploded view of the electrical connector of  FIG. 14 . 
         FIG. 17  is a perspective view of a shell housing of the connector of  FIG. 14 . 
         FIGS. 18-19  are rear and front isometric views of an electrically conductive shield ferrule of the connector of  FIG. 14 . 
         FIG. 20  is a side elevation view of a shield housing of the electrical connector of  FIG. 14 . 
         FIG. 21  is a cross-sectional view of the shield housing of  FIG. 20 . 
         FIGS. 22-23  are perspective views of an electrical connector for mating with the electrical connector of  FIG. 14 . 
         FIG. 24  is an exploded view of the electrical connector of  FIG. 22 . 
         FIG. 25  is a perspective view of an electrical connector according to another embodiment. 
         FIG. 26  is an exploded view of the electrical connector of  FIG. 25 . 
         FIG. 27  is an exploded view of an electrical connector according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to the drawings, this section describes particular embodiments of various electrical connectors and their detailed construction and operation. Throughout the specification, reference to “one embodiment,” “an embodiment,” or “some embodiments” means that a particular described feature, structure, or characteristic may be included in at least one embodiment of an electrical connector. Thus appearances of the phrases “in one embodiment,” “in an embodiment,” or “in some embodiments” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the described features, structures, and characteristics may be combined in any suitable manner in one or more embodiments. In view of the disclosure herein, those skilled in the art will recognize that the various embodiments can be practiced without one or more of the specific details or with other methods, components, materials, or the like. 
     The following describes example embodiments of an electrical connector system with pairs of mating connectors (e.g., mating connectors  100 ,  200 , mating connectors  300 ,  400 , or mating connectors  500 ,  650 ). The electrical connector systems may be used to connect two cable segments together for high-speed data transfer, for example, data transferred at rates of 1 gigabit per second and faster by signals generated at frequencies ranging from approximately 100 MHz to approximately 600 MHz and faster. In the following description, particular components of each of the electrical connectors are described in detail. It should be understood that in some instances, well-known structures, materials, or operations are not shown or not described in detail to avoid obscuring pertinent aspects of the embodiments. In addition, although the embodiments may reference electrical connectors having a specific arrangement or number of pin and socket connectors (and contacts), other embodiments may include differently configured components adapted to house more or fewer pin connectors. 
     With reference to  FIGS. 1-4 , an electrical connector  100  includes a housing  138  having a central housing base  140  and a pair of interlocking exterior shells  160  for retaining pin connectors  176 ,  178  in a ganged, co-aligned configuration. Additional details relating specifically to housing  138  are discussed below with particular reference to  FIG. 2 . Electrical connector  100  also includes a spacer  118  sized to fit between the pin connectors  176 ,  178  for physically separating the pin connectors  176 ,  178  from one another and aligning the pin connectors  176 ,  178  in a desired orientation to properly engaging a mating connector  200  (see  FIG. 5 ). The spacer  118  includes a central bore  122  that receives and secures a plug insert  102 . To help retain the mating connectors  100 ,  200  in an interlocked configuration, a pin head  104  protruding from the plug insert  102  mates with a socket  208  of the mating connector  200 , as described in further detail below. 
       FIGS. 3-4  illustrate detailed views of the plug insert  102  and the spacer  118 , respectively. With particular reference to these figures, the plug insert  102  includes a cylindrically shaped central shaft  106  having a pin head  104  on one end. The pin head  104  includes an elongated channel  108  extending axially along a side surface of the pin head  104 . Channel  108  receives a corresponding ridge  210  on a plug insert  206  of mating connector  200  (see  FIG. 7 ) to help secure the connection and proper orientation between the connectors  100 ,  200  when mated. Central shaft  106  further includes a ridge  110  sized to slidably fit in a channel  120  formed within a central bore  122  of the spacer  118 . 
     The plug insert  102  and the spacer  118  each include a plurality of blades  112 ,  128 , respectively, fanning outwardly in a radial direction from the central shaft  106  and central bore  122 , respectively. A pocket  116 ,  132  is formed between each of the blades  112 ,  128  to physically separate and accommodate the pin connectors  176 ,  178  as described previously. Each of these blades  112 ,  128  includes an opening or aperture  114 ,  130  sized to receive a screw, pin, or other suitable fastener (not shown) for securing the plug insert  102  against the spacer  118  when the connector  100  is assembled. In an assembled configuration, a back end (not shown, but opposite pin head  104 ) of the central shaft  106  on plug insert  102  is inserted through central bore  122  of spacer  118  such that ridge  110  aligns with and slides into channel  120 . In such a configuration, plug insert  102  rests against or is flush with spacer  118 , with pin head  104  extending outwardly from spacer  118  and blades  112  and apertures  114  aligning with and overlying blades  128  and apertures  130 , respectively. To secure the plug insert  102  to spacer  118 , a screw or other fastener is inserted through apertures  114 ,  130 . 
     Preferably, the plug insert  102  and spacer  118  are each made of metal (e.g., aluminum), plastic, or other suitable material. The plug insert  102  and/or the spacer  118  may also be electroless nickel plated to help prevent corrosion and wear. In some embodiments, instead of the plug insert  102  and spacer  118  being formed as separate components that are thereafter attached to one another, the two components may be formed as a single monolithic structure. 
     The following sections describes additional details of the housing  138  with particular reference to  FIG. 2 . As illustrated in the exploded view, housing  138  may include a central housing base  140  and a pair of housing shells  160 . In one embodiment, housing base  140  includes four generally U-shaped seats  142 , with two seats on a top side  144  and two seats on a bottom side  146 . Each seat  142  has a plurality of channels  148  extending transversely across the seat  142  to accommodate the pin connectors  176 ,  178  when in a fully assembled configuration as further described below. Housing base  140  includes a central bore  150  extending axially through the housing  138  and sized to receive a fastener  172  (see  FIG. 2 ) for securing the components of the electrical connector  100  together. 
     Housing base  140  further includes mounting apertures  152  positioned on each of top and bottom sides  144 ,  146  and sized to receive a boss  170  for securing the housing shells  160  (as further described below) thereto. The housing shells  160  each include a pair of seats  162  having transversely oriented channels  166  (similar to seats  142  and channel  148 ) and a dividing wall  164  separating the seats  162 . Shells  160  further include fastener apertures  168  corresponding in size and location to fastener apertures  154  of central housing base  140 . Housing  138  may be made of metal, such as aluminum, plastic or other suitable materials, including insulating materials. In an assembled configuration, one of housing shells  160  is positioned on top side  144  of housing base  140  and the other housing shell  160  is positioned on bottom side  146  of housing base  140 . Thereafter, the bosses  170  on housing shells  160  are snapped into apertures  152  on housing base  140  and screws  174  (see  FIG. 2 ) are threaded through the fastener apertures  154 ,  168  to complete assembly of housing  138 . 
     With general reference to  FIGS. 2-4 , the following description relates specifically to an example process for attaching spacer  118  to housing  138  to align pin connectors  176 ,  178  according to one embodiment. As shown in  FIG. 4 , spacer  118  includes a channel  124  formed within a cylindrical shaft  126 . With reference to  FIG. 2 , a cylindrical stem  156  extends from a front end of the housing base  140  and bears a ridge  158  sized to slide within and sit in channel  124  of spacer  118 . In an assembled configuration, spacer  118  is inserted into stem  156  such its shaft  126  wraps around stem  156  and ridge  158  slides into channel  124  to retain spacer  118  against stem  156 . It should be understood that in other embodiments, the particular mating components of the electrical connector  100  may be reversed. For instance, in other embodiments, ridge  110  on plug insert  102  may instead be a channel and channel  124  on spacer  118  may instead be a mating ridge. 
     The previous sections provided some description regarding assembly of particular components of the electrical connector  100  (e.g., assembly of the housing  138 , and mounting the plug insert  102  and spacer  118  together). The following section describes an example assembly of an electrical connector  100 . In one assembly method of an electrical connector  100 , prior to assembling the housing  138  as previously described, the pin connectors  176 ,  178  are positioned on or against seats  142  of central housing base  140 . Once pin connectors  176 ,  178  are properly aligned on seats  142 , housing shells  160  are positioned around housing base  140  to enclose pin connectors  176 ,  178  therein in a ganged, coaligned configuration. Thereafter, housing  138  is assembled as previously described to secure pin connectors  176 ,  178  in position. 
     After the pin connectors  176 ,  178  are seating in the housing  138 , spacer  118  is fitted between pin connectors  176 ,  178 , with blades  128  separating the individual pin connectors  176 ,  178  from one another. When spacer  118  is properly aligned, pin connectors  176 ,  178  rest against pocket  132  of spacer  118  and are held against a collar  134  of spacer  118  (see  FIG. 4 ). Plug insert  102  may thereafter be mounted onto spacer  118  as previously described to complete assembly of the electrical connector  100 . It should be understood that the assembly order described herein is for illustration purposes only and not intended as limiting. For instance, in other assembly methods, spacer  118  and plug insert  102  may be mounted together prior to fitting spacer  118  onto central housing portion  140 . 
       FIGS. 5-7  illustrate an embodiment of an electrical connector  200  configured to mate with the electrical connector  100  of  FIG. 1 . Electrical connector  200  may include a similar or substantially identical spacer  202  and housing  204  components as described with reference to electrical connector  100 . In addition, these components may be assembled in the same or similar process as described in relation to electrical connector  100 . Accordingly, to avoid repetition, similar components will not be further described in detail with respect to electrical connector  200 . As illustrated in  FIG. 7 , electrical connector  200  includes a plug insert  206  that has a few similar components as the plug insert  102  of electrical connector  100  (e.g., fanned out blades with mounting apertures), but also includes a socket  208  instead of the pin head  104 . The socket  208  is sized to receive pin head  104  when the connectors  100 ,  200  are mated. In addition, the socket connectors  212  of the electrical connector  200  include a socket  214  sized to engage pins  180 ,  182  of pin connectors  176 ,  178 . In such a configuration, electrical connector  100  may be inserted into mating connector  200 . Once inserted, a latch mechanism  35  (described below in further detail with reference to  FIG. 8 ) locks connectors  100 ,  200  in position. 
       FIG. 8  is a cross-sectional view illustrating an integrated latch mechanism  35  of the electrical connector  100  for latching together electrical connectors. The latch mechanism  35  includes lock pawls  50  that engage a corresponding structure (not shown) on the mating connector (e.g., connector  200 ) for retaining the connectors in a locked configuration. In some embodiments, pin connectors  178  of electrical connector  100  may include a latch release button  198  to disengage the lock pawls  50  and provide for easy release of electrical connector  100  from a mating connector  200  when needed. 
     With particular reference to  FIG. 8 , pin connector  178  includes a central shaft  15  having a first channel  20  and a second channel  25  thereon. When release button  198  is depressed downwardly toward shaft  15 , an engagement bulb  30  at the end of button  198  moves into the first channel  20  and urges shaft  15  to retract inwardly against spring  45 . When shaft  15  retracts, a groove  40  on a latch mechanism  35  slides into the second channel  25  and the latch mechanism  35  collapses downward, thereby releasing pin  178  from mating connector  200  and allowing easy removal. Other latching mechanisms actuated by a side-mounted button or other means are also contemplated within the scope of the present disclosure. Additional details of example embodiments for latch mechanism  35  are described in U.S. App. Pub. No. 2012/0171884, the disclosure of which is hereby incorporated by reference. 
     In some embodiments, only some of the pin connectors (e.g., pin connector  178 ) of electrical connector  100  will incorporate latch mechanism  35  and latch release button  198 , while other pin connectors (e.g., pin connectors  8 ) will not have such locking/unlocking components. In such configurations, it may be easier to decouple electrical connector  100  from mating connector  200  since only two latch release buttons  198  will need to be depressed instead of requiring simultaneous actuation of four latch release buttons  198 . In still other embodiments, electrical connector  100  may include only one pin connector with a latch mechanism and three connectors without a latch mechanism. It should be understood that in other electrical connectors, any number of pin connectors may include a latch mechanism. 
     In some embodiments, a grip bracket  186  may be fitted on electrical connector  100  to provide easier access to and actuation of release buttons  198  (see  FIG. 2 ). Grip bracket  186  includes a round base  188  that encircles a base of pin connectors  176 ,  178  and may include pockets  189  for accommodating the pin connectors  176 ,  178 . The grip bracket  186  includes a pair of cantilevered arms  190  extending outwardly from base  188  to provide a spring-return effect. Each of arms  190  includes an outward facing end with a textured or grooved surface  196  for enhancing user grip when pinching release buttons  198 . In some configurations, a bottom surface  194  of grip bracket  186  may loosely contact (without fully depressing button  198  inwardly) or may instead overlie release buttons  198  with a small gap/clearance to separate the components. Grip bracket  186  may be formed of a plastic material or other material having suitable durability and strength characteristics. 
     In an example operation, release button  198  may be actuated by grasping and squeezing textured surface  196  on grip bracket  186 , such as between a user&#39;s thumb and forefinger. The applied force depresses the arms  190  and actuates/depresses button  198  downwardly, which retracts shaft  15  in pin connector  178  to release latch mechanism  35  as described above. 
     In other embodiments, electrical connector  100  may comprise four pin connectors (similar to pin connectors  178 ) each having a latch mechanism  35  and a release button  198 . In such embodiments, therefore, electrical connector  100  comprises four pin connectors  178  with four latch release buttons  198 . To accommodate as design with the four release buttons  198 , grip bracket  186  may include additional cantilevered arms (similar or identical to arms  190 ) so that one cantilevered arm  190  is positioned over each of the latch release button  198  to provide a convenient grasping mechanism for depressing all four latch release buttons  198  simultaneously. For instance, in an example operation, a user may grasp the grip bracket  186  in one hand and depress all four cantilevered arms at once to actuate all four latch release buttons  198 . Thereafter, the user can pull apart and disengage the electrical connectors. 
     In some embodiments, grip bracket  186  may provide an additional structure for securing spacer  118 . For instance, grip bracket  186  may include a mounting aperture  192  (see  FIG. 2 ) sized to engage a corresponding aperture  136  on spacer  118  (see  FIG. 4 ). In such embodiments, a fastener  184  may be threaded through apertures  192 ,  136  to fasten spacer  118  to grip bracket  186 . 
       FIG. 9  illustrates a perspective view of a different embodiment for an electrical connector  300  and  FIG. 10  is an exploded view of the electrical connector  300 . With particular reference to  FIG. 10 , electrical connector  300  includes a plug insert  302 , a spacer  304 , and a housing  306 , all of which may include similar and/or identical functionality and components arranged as previously described with respect to electrical connector  100 . In some embodiments, the housing  306  may include different upper and lower housing portions  308  to accommodate a shell  310  for different electrical connector types/configurations. For instance, in some embodiments, shell  310  may be compliant with a MIL-DTL-38999 connector. 
     In some embodiments, the electrical connector  300  may include a shell-retention mechanism to secure shell  310  against the housing  306 .  FIG. 11  is a cross-sectional view of the electrical connector of  FIG. 9  illustrating an example embodiment of a shell-retention mechanism. In such embodiments, the spacer  304  of the electrical connector  300  includes at least one cantilevered tang  312  (also shown in  FIG. 10 ) having a locking pawl  314  for receiving and locking the shell  310  in position. In an example assembly, shell  310  is threaded or otherwise inserted into housing  306 . Once shell  310  is in proper position, a locking screw  316  is inserted and threaded through an aperture  136  (e.g., see  FIG. 4 ) on tang  312 . Threading screw  316  into aperture  136  urges tang  312  and toward a shoulder  318  of shell  310 . Screw  316  is threaded into aperture  136  until locking pawl  314  of tang  312  is pushed far enough outward to abut and arrest shoulder  318  of shell  310 . In such a configuration, tang  312  and locking pawl  314  resist movement of shell  310  away from electrical connector  300  and housing  306  (i.e., to inhibit disengagement of the shell  310 ). To remove shell  310 , screw  316  is unscrewed, which relaxes tang  312  and collapses locking pawl  314  away from shoulder  318 . 
       FIGS. 12-13  illustrate an embodiment of an electrical connector  400  (e.g. MIL-DTL 38999 connector) configured to mate with electrical connector  300  of  FIG. 9 . Mating connector  400  includes a plug insert  402 , spacer  404 , and connectors  414  which may include the same or similar features as previously described with respect to electrical connector  200 . Housing  406  may be similar to housing  306  of electrical connector  300 . A shell  408 , including a rotatable locking ring/nut  410  may be retained by electrical connector  400  via spacer  404  and tang  412  in a similar fashion as described with respect to shell  310  as illustrated in  FIG. 11 . Shell  408  is sized to engage shell  310  of electrical connector  300  when mating connector  400  and electrical connector  300  are linked. Locking ring  410  is threaded or provided with other means, such as a bayonet mount feature, for engaging and releasably joining shells  310  and  408 . 
       FIGS. 14-24  illustrate another embodiment of a pair of mating electrical connectors  500 ,  650  designed to provide increased electrical contact density for each connector  500 ,  650  for improved performance of high-speed data transfer. In the electrical connector system, an electrical connector  500  interfaces with an electrical connector  650  to create an electrical connection between two cables (not illustrated for clarity). The following description proceed with details of the components of the electrical connector  500 , followed by details of the electrical connector  650  (which preferably includes a number of identical parts as the electrical connector  500 ), and a description of an example coupling process of the connectors  500 ,  650 . 
       FIGS. 14-15  illustrate perspective views of the electrical connector  500 , and  FIG. 16  illustrates an exploded view of the electrical connector  500  according to one embodiment. With reference to  FIGS. 14-16 , the electrical connector  500  includes multiple socket contacts  502  housed in an electrically insulating (or electrically non-conductive) sheath  504  to physically separate the socket contacts  502  from one another. The sheaths  504  are grouped together (shown in groups of four in  FIG. 16 ) and seated within an electrically conductive shield ferrule  532 . The electrical connector  500  further includes a shield housing  550  suited to receive and compress the shield ferrules  532  and align the socket contacts  502  for insertion into a plug insert  506 . Additional details regarding the insulating sheaths  504 , the shield ferrule  532 , the shield housing  550 , and the plug insert  506  are provided below. 
     As briefly described above, the insulating sheath  504  houses the socket contacts  502 . In one embodiment, the insulating sheath  504  includes an interior chamber (not shown) with a pair of longitudinal channels running along a length of the sheath  504 , the channels separated from each other by a dividing wall. A socket contact  502  is seated and secured in each of the channels, with the socket contact  502  positioned along a front face of the sheath  504 . In such embodiments, each sheath  504  houses a pair of socket contacts  502  and maintains the socket contacts  502  physically separate from one another and properly aligned for mating with the electrical connector  650 . In one embodiment, each insulating sheath  504  is molded or machined from a polymeric material, for example, fiber reinforced or unreinforced amorphous thermoplastic polyetherimide resin such as ULTEM® 1000, sold by Sabic Innovative Plastics IP B.V. Company of the Netherlands, or other suitable insulating material. Additional details of example embodiments for insulating sheaths  504  for retaining contacts are described in U.S. App. Pub. No. 2012/0171884, the disclosure of which has been previously incorporated by reference. 
     With reference to  FIG. 16 , the electrical connector  500  includes a plug insert  506  for housing and arranging the sheaths  504  and socket contacts  502 . The plug insert  506  includes a plurality of cavities  508  arranged into distinct groups (four groups of cavities  508  are illustrated in  FIG. 16 ). Each cavity  508  extends in an axial direction entirely through the plug insert  506  and has a rear opening  510  proximate a rear face  512  of the plug insert  506 , and an opposite front opening  514  in a front face  516  of the plug insert  506  (see  FIG. 15 ). The plug insert  506  further includes a conductive central core  518  extending in the axial direction through the plug insert  506  for each group of cavities  508 . Conductive fins  520  radiate from the core  518  to physically separate adjacent cavities  508  from one another and to separate the sheaths  504  when inserted into the plug insert  506  as further described below. Preferably, the cavities  508  are sized and dimensioned to accommodate and surround a substantial portion of each insulating sheath  504  when the electrical connector  500  is assembled. 
     When the sheaths  504  are inserted into the plug insert  506 , socket contacts  502  held by sheath  504  are aligned with the front openings  514  of the cavity  508  so that the socket contacts  502  can receive pin contacts  678  of the electrical connector  650  (see  FIG. 23 ). When the sheaths  504  are housed in the cavities  508 , the conductive core  518  may provide additional physical support to retain and secure the sheaths  504  in a desired alignment within the cavities  508 . 
     In some embodiments, the number and arrangement of cavities  508  within the plug insert  506  will vary depending on a number and arrangement of sheaths  504  that will be housed therein and the size of the connectors  500 ,  650 . For instance,  FIGS. 14-16  illustrate one embodiment for a MIL-DTL-38999 size 19 connector designed to accommodate a total of sixteen sheaths  504  (and 32 total electrical contacts) separated into four groups of four. To accommodate the sheaths  504 , the cavities  508  are also separated into four groups of four. In other embodiments, such as for a MIL-DTL-38999 size 25 connector, the plug insert may be larger and capable of housing thirty-two sheaths (and 64 total electrical contacts) separated into eight groups of four. In still other embodiments, other arrangements and configurations are possible depending on the size and dimensional constraints of the connectors. 
     For instance,  FIG. 27  illustrates another embodiment of an electrical connector  800 . The electrical connector  800  includes a shell  802  and a plug insert  804  with a plurality of cavities (not shown) similar to the plug insert  506  described previously with reference to  FIG. 16 . The plug insert  804  includes a single conductive central core  806  with radiating fins  808  for receiving and retaining a group of four sheaths  810 , each sheath  810  housing electrical contacts (not shown). The connector  800  further includes a shield ferrule  812  and a shield housing  814  for retaining the sheaths  810  in a ganged, co-aligned configuration as further described in detail below with reference to the electrical connector  500  illustrated in  FIG. 16 . The shell  802  and a coupling nut  816  retain the components of the electrical connector  800  in place after assembly (as further described below with reference to  FIG. 16 ). In some embodiments, the shell  802  may be sized for a MIL-DTL-38999 size 9 connector. As illustrated, the size 9 connector is designed to accommodate a total of four sheaths  810  (and 8 total electrical contacts). 
     Turning back to  FIG. 16 , preferably, the plug insert  506  includes a plurality of cantilever members or tangs  522  formed on the sides of an exterior surface  524  thereof, each tang  522  having a radially outwardly projecting portion or catch  523  located proximate a free end of the tang  522 . In some embodiments, the plug insert  506  may include a total four tangs  522  on the exterior surface  524 , with each tang  522  facing an opposite tang  522 . When the electrical connector  500  is assembled, the plug insert  506  is inserted into the shell  526 , and the catch  523  of the tang  522  snaps into a corresponding notch or slot  528  on an interior surface of the shell  526  to hold the plug insert  506  in position at a desired configuration. The flexibility of the tangs  522  allow for a less restrictive engineering tolerance of the dimensions of the plug insert  506  with respect to the shell  528 . In addition, the tangs  522  also serve as guides for arranging the plug insert  506  within the shell  528  to ensure that the socket contacts  502  align with pin contacts  652  of the mating connector  650  (see  FIG. 23 ). In other embodiments, the plug insert  506  may not have tangs  522  and the plug insert  506  may instead be press fit into the shell  528 . In such embodiments, the engineering tolerance between the plug insert  506  and the shell  528  may be more restrictive to ensure a proper fit of the plug insert  506 . 
     In some embodiments, the plug insert  506  includes a recessed surface  530  on the exterior surface  524 , the recess  530  extending on the exterior surface  524  from the front face  516  toward the tangs  522 . In some embodiments, the tangs  522  may be aligned with the recesses  530 , where the tangs  522  are centered with respect to the recess  530  (as shown in  FIG. 17 ), but other configurations are possible. As further described in detail below with reference to  FIGS. 22-24 , when the connectors  500 ,  650  are mated, the interference fit between the cantilevered fingers  676  of the electrical connector  650  (see  FIG. 23 ) and the recess  530  provide a solid mechanical connection between the connectors  500 ,  650  and maintain shielding at the mating junction against external electromagnetic interference that may otherwise interfere with the cables terminated by the connectors  500 ,  650 . 
     With particular reference to  FIGS. 16 and 18-19 , the electrical connector  500  further includes an electrically conductive, annular shield ferrule  532  for retaining the insulating sheath  504  in a ganged, co-aligned configuration. In some embodiments, as illustrated in  FIG. 16 , the shield ferrule  532  may retain four individual sheaths  504 . In other embodiments, the ferrule  532  may retain more or fewer sheaths  504  as desired. With reference to  FIGS. 18-19 , the shield ferrule  532  includes a plurality of recesses  534  formed on an internal surface proximate a front end  536 . Each recess  534  is sized to receive an end (or other portion) of the sheath  504 . When assembled, each sheath  504  may snap into or otherwise sit within the recesses  534  to retain the sheaths  504  in a ganged alignment within the cavities  508  of the plug insert  506 . In some embodiments, a radiused or chamfered surface  538  surrounds each recess  534  to accommodate the sheaths  504  and facilitate encircling the sheaths  504  with the shield ferrule  532 . 
     The shield ferrule  532  further includes a plurality of cantilevered beams  540  formed on a back end  542 , and a waist portion  544  positioned between the front and back ends  536 ,  542  of the shield ferrule  532 . The waist portion  544  preferably has a smaller outer diameter than each of the ends  536 ,  542 . In some embodiments, longitudinal slots  546  formed on the shield ferrule  532  may create the cantilevered beams  540  and provide clearance for flexing the rear end  542  of the shield ferrule  532 . Additional details relating to the function/characteristics of the cantilevered beams  540  are described below with relation to the interaction between the shield ferrule  532  and the shield housing  550  in an assembled electrical connector  500 . 
     With reference to  FIGS. 16 and 20-21 , a shield housing  550  includes a lower base  552 , an upper head  558 , and an annular lip  554  between the lower base  552  and the upper head  558 . The shield housing  550  further includes a plurality of barrels  556  projecting in an axial direction from a surface of the upper head  558 . With particular reference to  FIGS. 20-21 , a cavity  560  extends entirely through the shield housing  550  (and the barrels  556 ) in the axial direction, the cavity  560  having an opening in a rear face  564  of the shield housing  550 , and an opposite opening in a front face  568  of the shield housing  550 . With particular reference to  FIG. 20 , the lower base  552  includes an internal wall  570  that tapers inwardly to gradually narrow the size of the cavity  560 . In some embodiments, the internal wall  570  may constantly taper inwardly from the rear face  564  to a narrow point  572  of the cavity  560 . In other embodiments (as illustrated in  FIG. 21 ), the internal wall  570  may have no taper at the rear face  564 , but begin tapering inwardly at a point distal from the rear face  564 . 
     When the electrical connector  500  is assembled, the shield ferrules  532  are inserted through the cavity  560  along the rear face  564  of the shield housing  550 . As the shield ferrules  532  are inserted, the sloped internal wall  570  urges the beams  540  to flex radially inwardly and constrict or narrow the back end  542  and the waist portion  544  of the shield ferrule  532 . As described previously, the shield ferrules  532  retain a back end of the sheaths  504 . When the sheaths  504  are inserted into the plug insert  506  and the shield ferrules  532  are inserted into the cavity  560  of the shield housing  550 , this constriction of the waist portion  544  urges forward movement of the sheaths  504  within the cavity  508  so that the socket contacts  502  are urged forward against the front opening  514  of the cavity  508  (see  FIG. 16 ). The radially inward flexure of the cantilever beams  540  may also cause beams  540  to clamp around wires/cables of the electrical connector  500  running through the shield ferrule  532 . Internal grooves  548  on each of the cantilever beams  540  facilitate gripping these wires/cables and provide strain relief as the cantilever beams  540  are flexed inwardly. 
     In some embodiments, the shield housing  550  may include a seal  574  retained in an internal channel  576  underneath the lip  554  (see  FIG. 21 ). The seal  574  functions to hinder moisture, dust, or other contaminants from entering the electrical connector  500 . As is further described in detail below, to help retain the seal  574  in position, the seal  574  may be compressed into the channel  576  by the rear face  512  of the plug insert  506  when the electrical connector  500  is assembled. In addition (or in an alternative embodiment), each of the barrels  556  include a plurality of circumferential grooves  578  on the exterior surface. A moisture ingress resistant seal may be formed over the barrels  556  by an adhesive-lined heat-shrink tube (not shown) that forms O-ring like seals in grooves  578  when the adhesive melts and re-solidifies. 
     With particular reference to  FIG. 16 , the electrical connector  500  further includes a coupling nut  580  and a backshell  596 , which, together with the shell  526 , house the components of the electrical connector  500 . The coupling nut  580  includes a threaded interior surface  582  proximate a rear end  584 . The threaded interior surface  584  is threaded to a pitch size that corresponds to a threaded external surface  586  of the shell  526 . A plurality of external teeth  588  are formed along an external circumference of the coupling nut  580  adjacent a front end  590  thereof. The teeth  588  may be regularly spaced-apart features, such as a series of evenly spaced vertical grooves, ridges, or other suitable features. In some embodiments, the teeth  588  are formed at approximately 5-degree intervals along the external circumference of the front end  590  of the coupling nut  580  for a total of 72 evenly-spaced teeth. In other embodiments, the coupling nut  580  may include more or fewer teeth that may be spaced apart at different intervals as desired. As is further described in detail below, the teeth  588  rest within an internal channel  606  of the backshell  596  and help prevent undesired rotation of the coupling nut  580 . The coupling nut  580  also includes a grip surface  592 , which may have a series of recessed portions or flats  594  or other suitable elements, to provide a gripping surface for tightening the coupling nut  580  onto the shell  526  during assembly of the electrical connector  500  as is further described in detail below. 
     As illustrated in  FIG. 16 , the backshell  596  preferably includes two clamshell housing sections  598  that may be fastened or mounted together, such as by inserting and securing fasteners  600  in the mounts  602 . The housing sections  598  may each have identical features that cooperate with one another to create various components of the backshell  596  as further described below. With particular reference to  FIG. 17 , the backshell  596  includes an opening  603  on a front face  604  and the circumferential internal channel  606  (with each housing section  598  forming half of the channel  606 ) is formed adjacent to and recessed relative to the opening  603 . The backshell  596  includes a pinhole slot  605  on each of the front faces  604  of the housing sections  598 , and a second slot  607  on an interior wall  609 . The pinhole slots  605 ,  607  are coaxially aligned relative to one another and configured to receive and retain a lock pin (not shown). 
     With reference to  FIGS. 16 and 17 , when the electrical connector  500  is assembled, the housing sections  598  of the backshell  596  are positioned around either side of the front end  590  of the coupling nut  580 . The housing sections  598  are brought together so that the teeth  588  of the coupling nut  580  are positioned within the internal channel  606  of the backshell  596  and may rest against the internal wall  609 . When the housing sections  598  are brought together, the lock pins move into position between a corresponding pair of teeth  588  (e.g., the lock pin sits in a valley between adjacent teeth  588 ). In this configuration, the lock pins arrest the coupling nut  580  and prevent undesirable loosening and/or rotation of the coupling nut  580  (such as may occur in response to vibrations or other external forces) after it has been tightened onto the shell  526 . 
     Preferably, the clamshell housing  596  includes an integrally formed strain relief  608  (with each housing section  598  forming half of the strain relief  608 ) adjacent a rear end  610  to provide a biting engagement against cables or other wiring of the electrical connector  500 . As illustrated in  FIG. 16 , strain relief  608  may provide an exit pathway oriented at 90-degrees (relative to a central axis of the electrical connector  500 ) for a cable or other wiring (not shown). In other embodiments, strain relief  608  may provide a differently angled exit pathway, such as 30-degrees, 45-degrees, 60-degrees, or another angle as desired. Alternatively, the strain relief  608  may provide a straight exit pathway (i.e., aligned with the central axis of the electrical connector  500 ). 
     Preferably, plug insert  506 , shield ferrule  532 , shield housing  550 , coupling nut  580 , and clamshell housing  596  are each made from an electrically conductive material, such as silver plated T6-7075 aluminum, for example. Other suitable materials, such as gold, nickel, aluminum alloys, steel, copper may also be used to coat or plate these components. In some embodiments, the components may be made from an insulating material, such as polyetherimide or other suitable engineering plastics, that is coated or plated with an electrically conductive material, such as silver, gold, or nickel. In a preferred embodiment, the plug insert  506 , shield ferrule  532 , shield housing  550 , and coupling nut  580  are each machined or otherwise manufactured (e.g. molded, injection molded, casted, etc.) as single, monolithic structures. 
     The following description relates to an example assembly operation of the electrical connector  500 , according to one embodiment. It should be understood that the described assembly steps are for illustration purposes only and do not intend to delineate any particular order for assembling the electrical connector  500 . With particular reference to  FIG. 16 , the sheaths  504  bearing the socket contacts  502  are inserted into the cavities  508  of the plug insert  506 . The front face of the sheath  504  is inserted into the cavity  508  so that the socket contact  502  is aligned with the front opening  514  on the front face  516  of the plug insert  506  (see  FIG. 15 ). To ensure that the sheaths  504  are inserted in a proper orientation, the sheaths  504  and cavities  508  may have matching cross sections (e.g., matching kidney-shaped cross sections) or other keyed features. Once all sheaths  504  have been inserted, each group of sheaths  504  (illustrated as a group of four in  FIG. 16 ), are banded together with an individual shield ferrule  532  (a total of four shield ferrules  532  are used in this embodiment). Each sheath  504  is inserted into the recess  534  on the front end  536  of the shield ferrule  532  (see  FIG. 18 ). When fully assembled, the shield ferrule  532  may sit against the rear face  512  of the plug insert  506 . 
     The shield housing  550  is thereafter positioned over the shield ferrules  532  to retain the four ferrules  532  in position. As described previously with respect to  FIGS. 19-20 , the cantilever beams  540  of the shield ferrule  532  are inserted into the cavities  560  of the shield housing  550 . The cantilever beams  540  are constricted by the tapering internal wall  570 , which in turn constricts the waist portion  544  to urge the sheaths  504  forward into the cavities  508  of the plug insert  506  as previously described. 
     The subassembly comprising of the plug insert  506  and the shield housing  550  are then inserted and pushed into the shell  526  until the tangs  522  of the plug insert  506  snap into the notches  528  on the interior of the shell  526 . In some embodiments, the shield housing  550  may be dimensioned with respect to the interior of the shell  526  so that there is a slight interference fit (e.g., 0.001-0.002 inches) when the shield housing  550  is inserted into the shell  526 . Once the subassembly is latched and retained within the shell  526 , the coupling nut  580  is threaded onto the shell  526 . In some embodiments, the coupling nut  580  may first be threaded by hand, and then a tool (e.g., a wrench) may be used to apply a desired amount of torque to tighten the coupling nut  580 . 
     Once the coupling nut  580  is threaded onto and secured to the shell  526 , the clamshell housing sections  598  are positioned on either side of the coupling nut  580  so that the teeth  588  of the coupling nut  580  are seated within the internal channel  606  of the backshell  596  to prevent rotation or loosening of the coupling nut  580 . The clamshell housing sections  598  are then secured via the fasteners  600  to complete the electrical connector  500 . 
       FIGS. 22-24  collectively illustrate an embodiment of an electrical connector  650  that mates with the electrical connector  500 . In some embodiments, electrical connector  650  includes many identical or substantially similar components as the electrical connector  500  and may be assembled in an identical fashion. For instance, with particular reference to  FIG. 24 , the electrical connector  650  includes insulating sheaths  652 , shield ferrules  654 , a shield housing  656 , and a coupling nut  658 , each preferably having identical features and arranged in an identical configuration as the corresponding components of the electrical connector  500 . To avoid repetition, details relating to these components of the electrical connector  650  may not be further described. The following description highlights certain components and features of the electrical connector  650  that are different from the electrical connector  500 . 
     With reference to  FIG. 24 , the electrical connector  650  includes a plug insert  660  that is similar to the plug insert  506  of the electrical connector  500 . For instance, plug insert  660  includes cavities  662  separated by a central core  664  and radiating fins  666  in an identical arrangement as described with respect to plug insert  506 . In addition, plug insert  660  includes tangs  668  for snapping the plug insert  660  into position within the shell  670 , which is preferably a MIL-DTL-39999 size 19 connector shell. Plug insert  660 , however, does not include recesses  530 , but instead includes tongues  672  extending from a front end  674  of the plug insert. The tongues  672  may be divided or sectioned to form a plurality of cantilevered fingers  676  with a corresponding length to bear against the conductive recesses  530  of the plug insert  506  (see  FIG. 16 ). Preferably, the fingers  676  engage the recesses  530  with an interference fit of approximately 0.001-0.002 inches to provide a solid mechanical connection between the connectors  500 ,  650  and maintain shielding at the mating junction against external electromagnetic interference that may otherwise interfere with the cables terminated by the connectors  500 ,  650 . 
     With reference to  FIG. 24 , the insulating sheath  652  of the electrical connector  650  houses pin contacts  678  with at least a portion of the pin contacts  678  extending forwardly from an end of from the sheath  652  so that the pin contacts  678  can be inserted into the socket contacts  502  when coupling the connectors  500 ,  650 . The electrical connector  650  includes a backshell  680  that preferably has similar features to backshell  596 , including the strain relief  682 , and the internal channel  684  for retaining the coupling nut  658  in position. 
     The following section describes an example coupling of the electrical connectors  500 ,  650  according to an example embodiment. With particular reference to  FIG. 15 , electrical connector  500  includes a plurality of splines  612  on an interior surface  614  of the shell  526 . Similarly, electrical connector  650  includes a plurality of channels  686  on an interior surface  688  of the shell  670  (see  FIG. 23 ). To couple the connectors  500 ,  650 , the splines  612  of the electrical connector  500  are aligned with the channels  686  of the electrical connector  650 . The splines  612  and the channels  686  are positioned on the respective connectors  500 ,  650  to ensure that the connectors  500 ,  650  are properly oriented relative to one another so that the pin contacts  678  are aligned with the socket contacts  502  and the cantilevered fingers  676  are aligned with the recesses  530 . Once the splines  612  and channels  686  are aligned, the connectors  500 ,  650  are pushed together toward one another until the pin contacts  678  are inserted into the socket contacts  502  and the fingers  676  bear against the recesses  530 . The connectors  500 ,  650  may be disengaged by pulling the respective connectors  500 ,  650  in opposite directions. 
       FIGS. 25-26  collectively illustrate another embodiment of an electrical connector  700 . In some embodiments, the electrical connector  700  may be a PCB connector and include many substantially similar components as the electrical connector  500 . For instance, with particular reference to  FIG. 26 , the electrical connector  700  may include a plug insert  702  (similar to plug insert  506 ) that has a plurality of cavities  704  extending axially through the plug insert  702  (similar to cavities  508  of plug insert  506 ) for receiving sheaths  706  that house PCB contacts  708 . The plug insert  702  further includes conductive central cores (not shown) similar to the cores  518  of the plug insert  506 . 
     The plug insert  702  includes a plurality of cantilever members or tangs  710  formed on the sides of an exterior surface  712  thereof, each tang  710  having a radially outwardly projecting portion or catch  714  located proximate a free end of the tang  710 . When the electrical connector  700  is assembled, the plug insert  702  is inserted into the shell  716 , and the catch  714  of the tang  710  snaps into a corresponding notch or slot  718  on an interior surface of the shell  716  to hold the plug insert  702  in position. In addition, the electrical connector  700  includes a coupling nut  720  with a threaded interior surface  722  that may be threaded onto the shell  716  in a similar fashion as described with reference to  FIG. 16  and electrical connector  500 . To avoid repetition, details relating to these components of the electrical connector  700  may not be further described. 
     With reference to  FIGS. 25 and 26 , the electrical connector  700  includes a PCB contact isolator  724  for retaining and isolating the sheaths  706  and PCB contacts  708  in a ganged, co-aligned configuration. The PCB contact isolator  724  includes a plurality of conductive central cores  726  each extending in the axial direction from a surface of the PCB contact isolator  724 . Conductive fins  728  radiate from the core  726  and physically separate adjacent pairs of PCB contacts  708  from one another around the central core  726  (see  FIG. 25 ). 
     The following description relates to an example assembly operation of the electrical connector  700 , according to one embodiment. It should be understood that the described assembly steps are for illustration purposes only and do not intend to delineate any particular order for assembling the electrical connector  700 . With reference to  FIGS. 25-26 , the sheaths  706  bearing the PCB contacts  708  are inserted into the cavities  704  of the plug insert  702 . Once all sheaths  706  have been inserted, the PCB contact isolator  724  may be positioned over the sheaths  706  so that the sheaths are inserted through the openings  730  of the PCB contact isolator  724 . In this configuration, each pair of PCB contacts  708  is positioned between two fins  728  of the conductive core  726  (see  FIG. 25 ). 
     The subassembly comprising of the plug insert  702  and the PCB contact isolator  724  are then inserted and pushed into the shell  716  until the catch  714  of the tangs  710  snap into the notch  718  on the interior of the shell  716 . Once the subassembly is latched and retained within the shell  716 , the coupling nut  720  is threaded onto the shell  716  to complete the electrical connector  700 . In some embodiments, the coupling nut  720  may first be threaded by hand, and then a tool (e.g., a wrench) may be used to apply a desired amount of torque to tighten the coupling nut  720 . 
     For clarity,  FIG. 26  only illustrates two groups of sheaths  706  that may be inserted into cavities  730  of PCB contact isolator  724 . However, in the embodiment illustrated in  FIG. 26 ), the PCB contact isolator  724  may be able to accommodate eight groups of sheaths  706  (for a total of 32 sheaths and 64 PCB contacts). It should be understood that in different embodiments, the PCB contact isolator  724  may accommodate more or fewer sheaths and PCB contacts as desired. 
     Other embodiments are possible. Although the description above contains much specificity, these details should not be construed as limiting the scope of the invention, but as merely providing illustrations of some embodiments of the invention. It should be understood that subject matter disclosed in one portion herein can be combined with the subject matter of one or more of other portions herein as long as such combinations are not mutually exclusive or inoperable. 
     The terms and descriptions used above are set forth by way of illustration only and are not meant as limitations. It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention.