Abstract:
A densely populated micro miniature connector includes a plug and a receptacle configured to securely mate with each other. Connector plugs include an insert assembly having at least one double-ended pin, a housing, and a coupling ring. Connector receptacles include an insert assembly having at least one spring probe and a housing. The double-ended pin contacts the spring probe when the plug and the receptacle are connected.

Description:
TECHNICAL FIELD 
       [0001]    The present application relates generally to cylindrical connectors having high performance capabilities for both general purposes and harsh environments. Generally, the connectors are used for low voltage data transmission. 
       BACKGROUND OF THE INVENTION 
       [0002]    Cylindrical connectors are typically used to join lengths of wires and to produce precision alignment of the wires for low voltage data transmission. Cylindrical connectors may be used, for example, in military applications, shipboard, aerospace applications, harsh environments, telecommunications, and armored applications. Conventional cylindrical connectors, such as MIL-DTL-38999 cables, include a plug and a receptacle, each having an insert assembly into which contacts are installed. Each individual contact is connected to a wire so precise alignment of the wires is possible when a plug contact is aligned with a receptacle contact. The insert assemblies require a contact retainer (or retaining ring) and a contact shoulder for each individual contact to lock each contact in place. However, only a limited number of contacts may be included in a connector of a given size due to the added size of including a retainer and shoulder for each contact; therefore, only a limited number of wires may be joined in a given cylindrical connector. For example, an insert assembly with shell size  13  has a diameter of about 0.522 inches and includes 22 contacts, while an insert assembly with shell size  17  has a diameter of about 0.772 inches and includes 55 contacts. Furthermore, insertion forces resulting from insertion and removal of contacts into conventional insert assemblies having retainers drag on the contacts and eventually lead to wear on the contacts. 
         [0003]    Therefore, a need exists for an improved connector that includes more contacts in a given area to join more wires than conventional cylindrical connectors of the same size. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention relates to cylindrical connectors having an increased number of contacts in a given area over conventional cylindrical connectors. Thus, a greater number of wires may be joined using smaller connectors. The cylindrical connectors of the present invention include a plug and a receptacle. The receptacle includes an insert assembly having at least one spring probe. The plug includes an insert assembly having a doubled-ended pin configured to contact the spring probe upon mating of the plug and receptacle. The plug insert assembly includes an interface seal, a front insert, a rear insert, and a seal, each having an opening through which at least one doubled-ended pin, conductive tube, and/or contact pin is inserted. The geometry of each opening is such that the double-ended pin is held in place without the use of a retainer. The doubled-ended pin may have a generally pointed tip and extends slightly beyond the end of the plug insert assembly. The plug insert assembly is positioned within a housing that is positioned within a coupling ring. The receptacle insert assembly includes a front insert, a rear insert, and a seal, each having an opening through which at least one spring probe, conductive tube, and/or contact pin is inserted. The geometry of each opening is such that the spring probe is held in place without the use of a retainer. The spring probe is enclosed within the receptacle insert assembly. The spring probe has a beveled tip configured to receive the generally pointed tip of the plug double-ended pin when mated with the plug insert assembly. The receptacle insert assembly is positioned within a housing configured to engage and lock with the connector plug. 
         [0005]    The geometry of the insert assemblies of the connectors allows for the inclusion of increased contacts in a given area over conventional connectors due to the elimination of the retainer required for conventional contacts. Furthermore, insertion forces that lead to wear of conventional contacts are minimized since the need for a contact retainer is eliminated. 
         [0006]    These and other aspects, objects, features and embodiments of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrated embodiments exemplifying the best mode for carrying out the invention as presently perceived. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The present invention may be better understood by reading the following description of non-limitative embodiments with reference to the attached drawings wherein like parts of each of the several figures are identified by the same reference characters, and which are briefly described as follows. 
           [0008]      FIG. 1A  is a perspective view of a plug according to an exemplary embodiment. 
           [0009]      FIG. 1B  is an exploded sectional view of the insert assembly of the plug of  FIG. 1A  according to an exemplary embodiment. 
           [0010]      FIG. 1C  is a sectional view of the housing and insert assembly of the plug of  FIG. 1A  according to an exemplary embodiment. 
           [0011]      FIG. 1D  is an exploded sectional view of the plug of  FIG. 1A  according to an exemplary embodiment. 
           [0012]      FIG. 2A  is a perspective view of a receptacle according to an exemplary embodiment. 
           [0013]      FIG. 2B  is an exploded sectional view of the insert assembly of the receptacle of  FIG. 2A  according to an exemplary embodiment. 
           [0014]      FIG. 2C  is an exploded sectional view of the receptacle of  FIG. 2A  according to an exemplary embodiment. 
           [0015]      FIG. 3A  is a sectional view of a connector showing the plug of  FIG. 1A  and receptacle of  FIG. 2A  disconnected according to an exemplary embodiment. 
           [0016]      FIG. 3B  is a sectional view of the connector of  FIG. 3A  showing the plug of  FIG. 1A  and receptacle of  FIG. 2A  partially connected according to an exemplary embodiment. 
           [0017]      FIG. 3C  is a sectional view of the connector of  FIG. 3A  showing the plug of  FIG. 1A  and receptacle of  FIG. 2A  fully connected according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The invention provides connectors for joining two lengths of wires. The connectors have high performance capabilities for both general purposes and harsh environments. Generally, connectors of the present invention include a plug and a receptacle, each having an insert assembly with increased contact density over conventional connectors. 
         [0019]    Referring to  FIG. 1A , a plug  100  includes an insert assembly  102 , a housing  104 , and a coupling ring  106 . Insert assembly  102  is disposed within housing  104 . Coupling ring  106  is configured to receive housing  104 , yet is capable of rotating independently of housing  104 . 
         [0020]      FIG. 1B  illustrates an expanded view of the insert assembly  102  of plug  100 . Insert assembly  102  is generally cylindrical. Insert assembly  102  includes an interface seal  108  coupled to a front insert  110 , which is coupled to a rear insert  112 , which is coupled to a seal  114 . Interface seal  108 , front insert  110 , rear insert  112 , and seal  114  may be coupled together by any means known to one having ordinary skill in the art. 
         [0021]    Interface seal  108  includes an opening  116  through which a front end  118  of a double-ended pin  120  may be inserted and compression sealed therein. In some embodiments, interface seal  108  may include a protrusion  109  extending therefrom and surrounding double-ended pin  120  upon insertion. Interface seal  108  may be fabricated from any sealing material. Suitable sealing materials include, but are not limited to, any materials suitable for fabricating grommet seals. 
         [0022]    Double-ended pin  120  includes a front end  118  having a generally pointed tip. However, one having ordinary skill in the art will recognize that the tip of double-ended pin  120  may be configured any number of ways as long as contact with a receptacle is possible. Double-ended pin  120  extends at least partially beyond a front end of insert assembly  102  and interface seal  108  ( FIG. 1C ) for insertion into a receptacle  200 . In some exemplary embodiments, double-ended pin  120  may be a beryllium copper double-ended pin. In other exemplary embodiments, double-ended pin  120  may be a stainless steel double-ended pin. One having ordinary skill in the art will recognize other suitable conductive materials for fabricating double-ended pin  120 . 
         [0023]    Front insert  110  includes an opening  122  through which a portion of a conductive tube  124  is inserted. In some embodiments, conductive tube  124  may be a copper tube; however, one having ordinary skill in the art will recognize other suitable conductive materials for fabrication of conductive tube  124 . A rear end  128  of double-ended pin  120  is positioned within the portion of conductive tube  124  disposed in opening  122 , while a central portion  126  of double-ended pin  120  is positioned directly within opening  122 . Central portion  126  of double-ended pin  120  has an outer diameter that is greater than the inner diameter of conductive tube  124 , thus preventing double-ended pin  120  from entirely being pushed into conductive tube  124 . Opening  122  has a diameter  122 d that is smaller than the outer diameter of central portion  126  of double-ended pin  120 , and prevents double-ended pin  120  from entirely being pushed out of opening  122 . Because double-ended pin  120  is retained within insert assembly  102  via central portion  126 , the need for the retainer required for insert assemblies having conventional contacts is eliminated. Thus insert assembly  102  may house more contacts (double-ended pins) per unit area than realized with conventional insert assemblies. Front insert  110  also may include a recess  130  designed to mate with a recess mating portion  132  of rear insert  112 . Front insert  110  may be fabricated from a non-conductive material, such as a glass-filled polymer or other suitable non-conductive material. For example, in some embodiments, front insert  110  may comprise poly-phenylene sulphide (PPS). 
         [0024]    Rear insert  112  includes an opening  134  through which a portion of conductive tube  124  is inserted. A front portion  136  of a contact pin  138  ( FIG. 1D ) is positioned within the portion of the conductive tube  124  within opening  134 . Rear insert  112  may be fabricated from a non-conductive material. Suitable examples of non-conductive materials include, but are not limited to, glass-filled polymers such as PPS. In some embodiments, contact pin  138  may be a beryllium copper wire crimped pin contact. 
         [0025]    Seal  114  is a grommet seal fabricated from a fluorosilicone rubber. Seal  114  includes an opening  140 , wherein at least a portion  142  of opening  140  has a diameter smaller than the outer diameter of conductive tube  124 . A rear portion  144  of contact pin  138  is positioned within opening  140  and sealed therein and includes an outer diameter greater than the portion  142  of opening  140 , thus preventing contact pin  138  from entirely being pushed into conductive tube  124  ( FIG. 1D ). In some embodiments, portion  142  of opening  140  may be positioned around a wire (not shown) and also prevents contact pin  138  from being pushed out of insert assembly  102  ( FIG. 1C ). Generally, a user may crimp a wire (not shown) into the rear portion  144  of contact pin  138  prior to insertion into insert assembly  102 . 
         [0026]      FIG. 1C  refers to insert assembly  102  and housing  104  of plug  100 . Housing  104  of plug  100  includes a cavity and is configured to house insert assembly  102  therewithin, as well as to be positioned at least partially within coupling ring  106  ( FIG. 1D ). Housing  104  includes a key  146  designed to fit and engage a key way of a mating receptacle  200  ( FIG. 2A ) to facilitate quick alignment and connection of the plug  100  and receptacle  200  by a user. In some embodiments, an electromagnetic interference (EMI) spring  148  may be included. When a plug  100  and mating receptacle  200  are connected, EMI spring  148  compresses and surrounds the mating connections of plug  100  and receptacle  200 , thus maintaining the electrical potential around the connections to avoid discharge into air gaps around the connectors. In other words, the inclusion of EMI spring  148  results in a connection such that the plug and receptacle units become a Faraday cage. 
         [0027]    Housing  104  also includes a ledge  150  that functions to position housing  104  within coupling ring  106  at a certain depth (which may vary from plug to plug). Additional grooves, such as groove  152 , may be include on the exterior of housing  104  as needed to facilitate coupling housing  104  to the interior of coupling ring  106 . Housing  104  may further include interior threads  154 . To facilitate coupling insert assembly  102  to housing  104 , a bonding ring  156  may be bonded to the exterior of seal  114  by any means known to one having ordinary skill in the art. Bonding ring  156  also includes exterior threads  158 . Exterior threads  158  mate with interior threads  154  of housing  104  and secure insert assembly  102  within housing  104 . 
         [0028]      FIG. 1D  refers to an exploded view of plug  100 . Coupling ring  106  includes a cavity and is configured to receive housing  104  therewithin, yet is capable of rotating independently of housing  104 . Once insert assembly  102  and housing  104  are inserted, a spiral retaining ring  160  positioned in groove  152  secures housing  104  to coupling ring  106 . In some embodiments, assorted washers and springs  162 , such as anti-rotational spring  164 , may be included as ratchet systems. Coupling ring  106  also may include threads  166  for matingly engaging a receptacle  200  ( FIG. 2A ). 
         [0029]    Referring to  FIG. 2A , a receptacle  200  includes an insert assembly  202  disposed within a housing  204 . Receptacle  200  is configured to mate with plug  100  as described below. 
         [0030]      FIG. 2B  refers to insert assembly  202 . Insert assembly  202  is generally similar to insert assembly  102 , with the difference being in the design of the front insert. Insert assembly  202  is generally cylindrical, and includes a front insert  206  coupled to a rear insert  208 , which is coupled to a seal  210 . Front insert  206 , rear insert  208 , and seal  210  may be coupled together by any means known to one having ordinary skill in the art. Rear insert  208  is similar to rear insert  112 , and seal  210  is similar to seal  114 . Front insert  206  includes an opening  212  into which a spring probe  214  is inserted, and spring probe  214  does not protrude outwardly from insert assembly  202 . In some embodiments, as shown in the Figures, opening  212  may include a portion having angled walls, or chamfer  212   c , and spring probe  214  may be recessed below the surface of front insert  206  and chamfer  212   c.    
         [0031]    Spring probe  214  includes a central portion  216  and a front end  218 . Spring probe  214  includes a spring (not shown) that may be disposed within central portion  216  and positioned proximate to front end  218 . Front end  218  acts as a plunger and may depress into central portion  216  upon force. Front end  218  of spring probe  214  includes a beveled tip configured to receive the tip of double-ended pin  120 . The spring in spring probe  214  allows the front end  218  to retract upon force from the front end  118  of double-ended pin  120  protruding out of plug  100  when plug  100  mates with receptacle  200 . In some embodiments, spring probe  214  may be a gold-plated beryllium copper double-ended pin, such as the Series S, Size 00, G Plating, 1.3 Spring Force probe commercially available from Interconnect Devices, Inc. In other embodiments, spring probe  214  may be a gold-plated double-ended pin having a stainless steel internal spring, such as the Series S, Size 00, G Plating, 1.6 Spring Force probe commercially available from Interconnect Devices, Inc. 
         [0032]    A portion of a conductive tube  220  (similar to conductive tube  124 ) is partially inserted into opening  212 . At least a portion of spring probe  214  is positioned within the portion of conductive tube  220  that is partially inserted into opening  212 . Central portion  216  of spring probe  214  has an outer diameter that is greater than the inner diameter of conductive tube  220 , thus preventing spring probe  214  from entirely being pushed into conductive tube  220 . Because spring probe  214  is retained within insert assembly  202  via central portion  216 , the need for the retainer required for insert assemblies having conventional contacts is eliminated. Thus, insert assembly  202  may house more contacts (spring probes) per unit area than realized with conventional insert assemblies. 
         [0033]    Front insert  206  may include a recess  222  designed to mate with a recess mating portion  224  of rear insert  208 . Front insert  206  may be fabricated from a non-conductive material, such as a glass-filled polymer. In some embodiments, front insert  206  may comprise PPS. 
         [0034]    A front portion  236  of contact pin  238  ( FIG. 2C ) is positioned within the portion of the conductive tube  220  within an opening  226  of rear insert  208 . A rear portion  244  of contact pin  238  is positioned within opening  228  of seal  210  and sealed therein. Generally, a user may crimp a wire (not shown) into the rear portion  244  of contact pin  238  prior to insertion into insert assembly  202 . 
         [0035]      FIG. 2C  refers to an exploded view of receptacle  200  showing insert assembly  202 , housing  204 , contact pin  238 , and bonding ring  156 . Housing  204  of receptacle  200  is configured to house insert assembly  202  within. A bonding ring  156  may be used to secure insert assembly  202  within housing  204  similar to the way insert assembly  102  is secured to housing  104 . Housing  204  includes a key way  230  designed to receive and matingly engage key  146  of plug  100  and to secure the plug  100  and receptacle  200  together. Housing  204  may further include a mounting surface  232  for mounting receptacle  200  to a surface or box (not shown). 
         [0036]    Referring to  FIGS. 3A-3C , a connector  300  of the present invention includes a plug  100  and a receptacle  200 .  FIG. 3A  refers to plug  100  and receptacle  200  disconnected.  FIG. 3B  refers to plug  100  partially connected to receptacle  200 , whereby front end  118  of double-ended pin  120  enters opening  212  of front insert  206  of receptacle  200 . At this stage, front end  118  of double-ended pin  120  may or may not be in contact with front end  218  of spring probe  214 , and therefore conductive contact may not be achieved. Referring to  FIG. 3C , when plug  100  completely mates with receptacle  200 , protrusion  109  of interface seal  108  enters the chamfer  212   c  of front insert  206  and spring action allows compression of spring probe  214  to achieve definite conductive contact and an environmental seal between plug  100  and receptacle  200 , and coupling ring  106  rotates independently and locks the plug  100  and receptacle  200  in place. Coupling ring  106  and anti-rotational spring  164  may aid in preventing coupling ring  106  from accidentally unlocking or unthreading after plug  100  and receptacle  200  are engaged. Thus, an improved connector is realized achieving similar environmental performance levels of conventional connectors, while having an increased contact number per unit area. For example, an insert assembly with shell size  13  has a diameter of about 0.522 inches and can include 55 contacts according to an exemplary embodiment of the invention, while an insert assembly with shell size  17  has a diameter of about 0.772 inches and can include 139 contacts. Additionally, the inclusion of the spring probe  214  eliminates the insertion forces that were present in conventional connectors. 
         [0037]    Therefore, the present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those having ordinary skill in the art having the benefit of the teachings herein. Having described some exemplary embodiments of the present invention, it is believed that the use of alternate housing configurations and coupling rings is within the purview of those having ordinary skill in the art. Additionally, while the present application generally illustrates cylindrical insert assemblies, housings, and coupling rings, it is understood that a number of other non-circular configurations may be used. Furthermore,  FIGS. 1B-1D ,  2 B- 2 C, and  3 A- 3 C illustrate connector units having a single double-ended pin and/or spring probe for convenience. However, it is understood that multiple double-ended pins and/or spring probes may be included within the insert assemblies by duplicating the items in a desired pattern, as limited by the cross-sectional area of the insert assemblies. 
         [0038]    Additionally, certain alternative exemplary embodiments are within the scope of the present invention. For example, the spring probe in the receptacle may extend beyond the corresponding front insert, and the double-ended pin in the plug may be recessed within the corresponding front insert by modifying the design of the front inserts accordingly. Furthermore, the spring probe can be used in the plug instead of the receptacle, and the double-ended pin can be used in the receptacle instead of the pin. 
         [0039]    While numerous changes may be made by those having ordinary skill in the art, such changes are encompassed within the spirit of this invention as defined by the appended claims. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present invention. The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.