Patent Publication Number: US-6669502-B1

Title: High-speed axial connector

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to an axial connector for positioning and retaining wires and contacts in a fixed position. 
     Coaxial connectors have been proposed that are mountable to the ends of lines in a cable, such as one that carries one or more differential signals. For instance, quad cables are used for conveying high-speed data communications. The quad cables include one pair of transmit lines and one pair of receive lines, all of which are twisted in a helix to maintain a desired orientation with respect to one another. When a connector is attached to a quad cable, it is preferable to maintain the transmit and receive lines in a fixed geometry. The transmit and receive lines are connected to transmit and receive contacts which are located in a particular relation to one another within the connector. In the event that the spacing between, or overall geometry of, the transmit and receive lines and/or contacts is disturbed from a preferred configuration, particular receive and/or transmit lines begin to interact with one another in a detrimental manner. For example, such detrimental electromagnetic interaction may cause degradation in the signal-to-noise ratio, impedance and the like. 
     One conventional quad connector includes a tubular shell having a hollow core configured to receive a two-piece dielectric material that hold contacts connected to lines of the quad cable. The two-piece dielectric included a rear dielectric segment stacked end-to-end with a lead guide dielectric segment, where each segment is molded separately. The lead guide segment included a group of holes therethrough arranged in a pattern in which the contacts are held. Lead portions of each contact are loaded through the back end of the guide segment. Once loaded into the guide segment, the contacts have rear portions extending from the back end of the guide segment. 
     The rear dielectric segment of the two-piece dielectric is side loaded onto the rear portions of the contacts that extend from the guide segment. The rear dielectric segment is tubular in shape and includes two slots cut in the side thereof, with the slots being separated by an insulated interior wall. Rear portions of the contacts were side loaded into the slots in the split section. The slots extend along the length of the rear dielectric segment. The rear portions of the contacts are formed with a ribbed or raised peripheral segment surrounding the main body of each contact. The main body of each contact is formed with a first diameter, while the raised portion is formed with a larger second diameter. The slots cut in the split dielectric segment are notched to define a stepwise slot width having ledges dimensioned to interlock with the raised portion of each contact. 
     The interlocking relation formed between the slots and the raised portions of the contacts resists longitudinal movement of the contacts along the length of the rear split dielectric segment. The split dielectric segment abuts against the rear end of the guide dielectric segment, thereby preventing longitudinal movement of the split dielectric segment within the connector shell, which in turn prevented movement of the contacts along the length of the connector. 
     However, previously proposed connector designs have met with limited success. The interlocking features formed within the split dielectric segment and on the contacts require that the dielectric be made of two pieces, namely with a lead guide dielectric segment to align the contacts and with a rear split dielectric segment to lock the contacts at a fixed longitudinal position within the contact shell. The connectors have very small overall size and are assembled in large quantities. Hence, the use of a multi-piece dielectric unduly complicated the manufacturing process. 
     Further, previously proposed connectors have been unable to satisfactorily maintain the contacts in a desired geometry within the connector, as well as resist movement of the contacts along the longitudinal axis of the connector. 
     A need remains for an improved axial connector that may be easily and reliably manufactured with few components and that provides wire management and contact positioning and orientation. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention generally relates to a connector for conveying high-speed data signals, and more specifically to an axial connector having a dielectric member that securely positions and orients the contacts in a desired geometry within the connector. The dielectric member has a deflectable portion that securely retains contacts at a fixed longitudinal position along the connector. 
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 illustrates an exploded isometric view of a connector assembly formed in accordance with an embodiment of the present invention. 
     FIG. 2 illustrates an end isometric view of a dielectric member formed in accordance with an embodiment of the present invention. 
     FIG. 3 illustrates a side sectional view of a dielectric member taken along line  3 — 3  in FIG.  2 . 
     FIG. 4 illustrates a side view of a disassembled connector assembly and cable in accordance with an embodiment of the present invention. 
     FIG. 5 illustrates a partially assembled connector assembly and cable in accordance with an embodiment of the present invention. 
     FIG. 6 illustrates a side sectional view of a connector assembly and partially loaded cable formed in accordance with an embodiment of the present invention. 
     FIG. 7 illustrates a side sectional view of a connector assembly partially loaded with a cable in accordance with an embodiment of the present invention. 
     FIG. 8 illustrates a side sectional view of a connector assembly and fully loaded cable in accordance with an embodiment of the present invention. 
     FIG. 9 illustrates an exploded isometric view of a socket connector assembly formed in accordance with an embodiment of the present invention. 
     FIG. 10 illustrates a side sectional view taken along line  10 — 10  in FIG. 9 of a dielectric member formed in accordance with an embodiment of the present invention. 
     The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates an exploded isometric view of a connector assembly  10  formed in accordance with an embodiment of the present invention. The connector assembly  10  includes an outer shell  12  that receives therein a dielectric member  14  and a ferrule  16 . A plurality of contacts  18  are mounted to corresponding signal wires  20  and inserted through the ferrule  16  into the dielectric member  14 . The signal wires  20  are held within a cable  22 . An outer braid  24  is folded back upon the cable  22  to expose the signal wires  20  (each of which is individually insulated). 
     In certain applications, the signal wires  20  may be grouped into differential pairs and arranged in a particular geometry, such as a quadrature arrangement with a transmit pair  26  and a receive pair  28  as in the example of FIG.  1 . Alternatively, the number of signal wires  20  may be varied and the geometry thereof may be changed. By way of example only, the number of signal wires  20  may be varied to include two wires, three wires, eight wires and the like. 
     The contacts  18  are each formed with a body section  30  having a pin  32  extending from a lead end thereof. Each body section  30  has a larger diameter than the diameter of the corresponding pin  32  in order to define a shoulder  34  therebetween. The body section  30  includes a flared section  31  defining a second shoulder  35 . Each shoulder  34  and  35  may be sloped or step-wise. Each body section  30  further includes a rear socket  36  formed thereon and extending opposite to the pin  32 . The rear socket  36  is hollow and configured to receive the conductors of a corresponding signal wire  20 . The rear sockets  36  may be affixed to corresponding signal wires  20  in a variety of manners, such as soldering, crimping and the like. As a further option, the overall configuration and shape of the contacts  18  may be varied and need not include pins  32 . Instead, the contacts may include blade portions, or any other well-known contact shape. 
     The ferrule  16  includes an opening  38  therethrough and a rim  40  at the rear end of the ferrule  16 . The ferrule  16  is inserted over the contacts  18  until resting upon the cable  22 . The ferrule  16  includes an exterior wall  42  that is dimensioned to be received within braid  24  and to sandwich the braid  24  between the ferrule  16  and the outer shell  12  with the rim  40  proximate a loading end  44  of the outer shell  12 . 
     The outer shell  12  is generally tubular in shape and is formed with a mating end  46  configured to be joined with a corresponding connector assembly (such as a socket connector assembly as discussed below). The outer shell  12  includes a cavity  48  extending therethrough between the loading and mating ends  44  and  46 . The outer shell  12  includes a lead portion  50  dimensioned to be received within a mating connector assembly. A rim  52  is provided at an interface between the lead portion  50  and a body portion  54 . The body portion  54  includes an indentation formed along the length of the body portion  54 , thereby defining a keying feature  56  that projects into the cavity  48 . The keying feature  56  extends in a direction parallel to a longitudinal axis  58  of the connector assembly  10  (also referred to as the center line of the outer shell  12 ). 
     The dielectric member  14  may be a unitary structure formed from a single piece of insulative material. The dielectric member  14  includes front and rear ends  60  and  62  oriented along the longitudinal axis  58 . A plurality of contact passages  64  are formed within the dielectric member  14  and extend between the front and rear ends  60  and  62 . The contact passages  64  are formed in a predefined geometry relative to the longitudinal axis  58  of the connector assembly  10  based on the particular application and geometry of the cable  22 . A keying notch  66  is formed in the exterior of the dielectric member  14  and extends rearward from the front end  60 . The keying notch  66  is shaped to align with the keying feature  56  projecting into the cavity  48 . The dielectric member  14  includes a lead section  68  having a smaller diameter than an intermediate body section  70 . The lead section  68  extends into the lead portion of the cavity  48  within the lead portion  50  of the outer shell  12 . A rim  72  is formed on the dielectric member  14  at the interface between the lead and body sections  68  and  70 , which locates the dielectric member  14  at a predetermined depth within the outer shell  12  from the mating end  46  along the longitudinal axis  58 . The dielectric member  14  also includes a flared section  74  (also referred to as a contact gripping section) formed proximate the rear end  62 . The flared section  74  has an outer envelope with a larger diameter proximate the rear end  62  than the diameter of the body section  70 . In the example of FIG. 1, a ramped surface  76  forms a lead-in transition area between the body and flared sections  70  and  74 . Optionally, the ramped surface  76  may be formed in a stepwise manner to afford a more sharp transition, or may be more gradually sloped up to the rear end  62 . As a further option, the flared section  74  may have the same diameter throughout (or even a lesser diameter throughout) than the diameter of the body section  70 . 
     The dielectric member  14  further includes a plurality of collets  78  cut or formed therein and extending from the rear end  62  forward in a direction parallel to the longitudinal axis  58 . Optionally, the collets  78  may be cut or formed in a pie or spiral pattern with respect to the longitudinal axis  58 , and extending along the dielectric member  14 . The collets  78  in the example of FIG. 1 are evenly distributed about the perimeter of the dielectric member  14 . Alternatively, the collets  78  need not be distributed about the entire perimeter, but instead may be grouped unevenly on selected sides of the dielectric member  14 . In the example of FIG. 1, the collets  78  extend through the flared section  74  into the body section  70 . Alternatively, the collets  78  may terminate within the flared section  74  or may extend entirely or substantially through the body section  70 . 
     The collets  78  define a plurality of legs  80  that are clustered about, and extend parallel to, the longitudinal axis  58 . Each leg  80  includes a the ramped surface  78  which joins a crimping surface  82 . The legs  80  are deflectable and configured to be compressed to collapse inward radially toward the longitudinal axis  58 . As explained below in more detail, the legs  80 , when collapsed, compressably and frictionally grip the signal wires  20  to retain the contacts  18  at a particular depth relative to the mating end  46  of the outer shell  12  along the longitudinal axis  58 . Optionally, the legs  80  may be positioned and configured to directly grip and frictionally engage the body sections  30  or rear sockets  36  of the contacts  18 . When collapsed, the contact passages  64  retain the pins  32  in a predefined pattern or geometry with respect to the longitudinal axis  58 . 
     FIG. 2 illustrates an end isometric view of the dielectric member  14  with the rear end  62  visible. In the example of FIG. 2, each contact passage  64  is surrounded and defined by a pair of legs  80  and a dielectric core  84 . The dielectric core  84  has a series of radiused surfaces  86  notched in its exterior and about its perimeter. Each radiused surface  86  extends along the length of the dielectric member  14  to define one side of a corresponding contact passage  64 . Interior surfaces  88  of each leg  80  are similarly radiused or curved such that when a corresponding pair of legs  80  are compressed inward radially toward the dielectric core  84 , interior surfaces  88  of adjacent legs  80  are positioned substantially adjacent (and may abut against) one another to define a curved wall of the corresponding contact passage  64 . The dielectric core  84  separates adjacent radiused surfaces  86  with ledges  90  facing outward. The ledges  90  may be and positioned to abut against the interior surfaces  88  of the legs  80 , in order to prevent the flared section  74  from being unduly collapsed until destructably compressing the signal wires  20  and/or contacts  18 . Optionally, the interior surfaces  88  and ledges  90  may be dimensioned to avoid one another in embodiments in which it is desirable to permit the legs  80  to be compressed inward by an unlimited amount. 
     FIG. 3 illustrates a side sectional view taken along line  3 — 3  in FIG. 2 of the dielectric member  14 . As illustrated in more detail in FIG. 3, the contact passages  64  are formed with a stepwise diameter to define lead, intermediate and rear portions  92 ,  94  and  96 , respectively. The lead portions  92  have a smaller diameter than the intermediate portions  94  which in turn have a smaller diameter than the rear portions  96 . Shelves  98  and  100  are formed at the points of intersection between the lead and intermediate portions  92  and  94 , and between the intermediate and rear portions  94  and  96 , respectively. 
     With reference to FIGS. 1 and 3, the contacts  18  are inserted into the contact passages  64  until the shoulders  35  at the flared portion  31  on each contact  18  engage a corresponding shelf  100  within the contact passages  64 . The shelves  100  and shoulders  35  cooperate to locate each contact  18  at a predefined point along the length of the longitudinal axis  58  (FIG. 1) with respect to the mating end  44  of the connector assembly  10 . Optionally, the shoulder  34  on each contact  18  may also engage a corresponding shelf  98 . 
     FIG. 4 illustrates an exemplary cross-section of the outer shell  12 . The outer shell  12  is constructed with an O-crimp section  102  formed proximate the loading end  44 . The O-crimp section  102  represents a ring having a larger interior diameter than an interior ring of the body portion  54  to define a ledge  104  therebetween. The ledge  104  is configured to engage the ramped surfaces  76  on each of the legs  80  to collapse the collets  78 . 
     Next, FIGS. 4-8 are referenced to explain an exemplary order of operations through which the connector assembly  10  is connected to the cable  22 . The outer insulator on the end of the cable  22  is stripped and the braid  24  is dressed back over the outer insulator to expose a portion of the signal wires  20 . Ends of the signal wires  20  are stripped of insulation and secured within the rear sockets  36  of corresponding contacts  18 . (FIG. 4) The ferrule  16  may be slid over the cable  22  before or after stripping the insulation and before dressing back the braid  24 . 
     As shown in FIG. 5, the dielectric member  14  may be inserted into the outer shell  12  before the contacts  18  are inserted into the dielectric member  14 . Optionally, the contacts  18  may be first inserted into the dielectric member  14  which is then inserted into the outer shell  12 . As shown in FIG. 6, the contacts  18  are loaded into the contact passages  64  until the pins  32  are received within the lead portion  50  of the outer shell  12 . As shown in FIG. 7, contacts  18  are further loaded in passages  64  until fully seated relative to dielectric member  14  with shoulders  34  and  35  abutting against ledges  98  and  100 , respectively. With reference to FIG. 7, the ferrule  16  is slid forward in the direction of arrow A until the exterior wall  42  is received within the interior pocket  25  of the braid  24 . The ferrule  16  is pressed forward in the direction of arrow A relative to the outer shell  12 , thereby further engaging dielectric  14 , and therein fully loaded contacts  18 , within outer shell  12 . 
     As shown in FIG. 8, the ferrule  16  is further slid forward in the direction of arrow A with respect to the outer shell  12  until the ferrule  16  is seated within the O-crimp section  102  of the outer shell  12 . Optionally, the rim  40  may be slid forward until proximate or abutting against the loading end  44  of the outer shell  12 . By pressing the ferrule  16  forward in this manner, pressure is also applied to the dielectric member  14  which causes the ramped surfaces  76  on each leg  80  to be deflected radially inward by the ledge  104 . As the ledge  104  compresses the legs  80  inward, the interior surfaces  88  of each ledge  80  compressively and frictionally engage the signal wires  20  (and/or contacts  18 ) within corresponding contact passages  64 . The dielectric member  14  is pushed forward until the rim  72  on the dielectric member  14  seats against a ledge  73  in the cavity  48  to locate the front end  60  a defined depth from the mating end  46  of the outer shell  12 . The tips  33  of pins  32  are also a fixed distance from the front end  60 , which ensures that the pins  32  are at a known location within the outer shell  12 . The flared section  74  and ferrule  24 , when crimped by O-crimp section  102  firmly grip the signal wires  20  to resist movement in the direction of arrow B. 
     FIG. 9 illustrates a socket connector assembly  210  configured to mate with the connector assembly  10  of FIG.  1 . The socket connector assembly  210  includes an outer shell  212 , a dielectric member  214 , a ferrule  216 , socket contacts  218 , signal wires  220  and a cable  222 , aligned along a longitudinal axis  258 . The foregoing structure is designed to interconnect in a manner similar to that explained above in connection with the connector assembly  10  of FIG.  1 . The socket contacts  218  are configured slightly different from contacts  18  in that the body sections  230  include socket sections  232  on lead ends thereof having pin receptacles  233  formed therein. The pin receptacles  233  are configured to receive and form an electrical connection with the pins  32  when contacts  18  and  218  are joined. The dielectric member  214  is configured with a lead section  268  slightly longer than the lead section  68  of the connector assembly  10 . The pins  32  on contacts  18  (FIG. 1) are received within contact passages  264  of the dielectric member  214  such that the connection between pins  32  and socket sections  232  is formed within the lead section  268 . The dielectric member  214  includes a keying notch  266  formed therein and configured to align with a keying feature  256  projecting into the interior of the cavity  248  in outer shell  212 . The outer shells  12  and  212  also include keying features to insure a particular alignment therebetween when mated, in order that particular contacts  18  are adjoined with an associated socket contact  218 . 
     The outer shell  212  further includes a lead portion  250  configured to receive the lead portion  50  of connector assembly  10 . The lead portion  250  includes, within the cavity  248 , a plurality of compliant body segments  251  separated by slots  253  that are biased radially inward. The body segments  251  firmly engage the exterior of the lead portion  50 , thereby insuring a firm connection therebetween. The outer shells  12  and  212  may be conductive to afford a grounded shield surrounding the contacts  18  and  218 . Optionally, the outer shells  12  and  212  may have an insulated exterior. 
     FIG. 10 illustrates a side sectional view taken along line  10 — 10  in FIG. 9 of the dielectric member  214 . The dielectric member  214  includes contact passages  264  that may have a step-wise radius to form a shelf  300 . The shelf  300  is configured to abut against and engage a shoulder  235  (FIG. 9) at a flared portion  231  on a corresponding contact  218  to insure proper alignment along the longitudinal axis  258  of the socket contacts  218  with respect to the socket connector assembly  210  (FIG. 9) and dielectric member  214  (FIG.  10 ). The contact passage  264  further includes a front wall  265  having an opening  267  therethrough. The wall  264  forms a shelf  298  against which the lead end of the socket section  232  of each socket contact  218  may abut. 
     When the connector assembly  10  is fully mated with the socket connector assembly  210 , corresponding contact passages  64  and  264  are aligned with one another, such that center lines  106  (FIG. 3) of contact passages  64  coincide with center lines  306  (FIG. 10) of contact passages  264 . Once the flared sections  74  (FIG. 2) and  274  (FIG. 10) are collapsed, the corresponding signal wires  20  and  220  (or contacts  18  and  218 , respectively) are held in a particular orientation and alignment along the center lines  106  and  306  with respect to the longitudinal axes  58  and  258 , respectively. Hence, the connector assembly  10  and socket connector assembly  210  achieve the desired wire management and positioning and orientation of the contacts  18  and  218  and wires  20  and  220 , both radially and longitudinally with respect to the longitudinal axes  58  and  258 . 
     O-crimp sections  102  and  302  on the outer shells  12  and  212 , respectively, further compress the flared sections  74  and  274  and ferrules  16  and  216 , respectively. 
     Optionally, the dielectric member  14  may be formed with slots cut in the sides of the flared section  74  to permit the lead in portions of the contacts to be side loaded before being inserted into the body and lead sections  68  and  70  of the dielectric member  14 . When such slots are used, optionally, only a pair of collets may be cut in opposite sides of the flared section  74 . 
     Optionally, the outer shell need not be crimped onto the flared sections  74  and  274 . Instead, the flared sections  74  and  274  may be collapsed in other manners so long as the gripping force is sufficient to maintain the contacts in a stable and unmovable position with respect to each outer shell. By preventing rearward movement of the contacts when experiencing mating forces along the length of the contacts, the connector assemblies insure that the contacts (pin and receptacle) are fully joined when the outer shells are fully joined. 
     While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted 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 its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.