Patent Publication Number: US-6705894-B1

Title: Shielded electrical connector

Description:
FIELD OF THE INVENTION 
     This invention generally relates to the art of electrical connectors and, particularly, to a shielded electrical connector which has a pair of shielding backshell halves which may be hermaphroditic. 
     BACKGROUND OF THE INVENTION 
     A typical electrical connector includes some form of dielectric housing or insert which mounts a plurality of conductive terminals. The terminals may be terminated to discrete electrical wires or conductors of a composite electrical cable. The terminals have contact portions generally at a front mating end or face of the connector for electrically engaging the terminals of a complementary mating connector at a mating interface. 
     In many electrical connector applications, such as in the telecommunication and/or data communication industries, an electrical connector typically includes some form of metal shroud or shield surrounding the electrical terminals or a least the contact portions of the terminals at the mating interface. The shroud or shield provides electromagnetic interference and/or radial frequency interference (EMI/RFI) protection for the connector. In some connectors, the metal shroud or shield is provided by a pair of outer shell members which are interconnected about the interior dielectric and terminals of the connector. The shell members have some form of means for holding the shells together about the connector. For instance, fasteners such as screws may be used, but such fasteners require inventory maintenance and the assembly of such fasteners is not cost and time effective. Some shell halves have thin interengaging hooks, which are susceptible to breakage, and if the backshell halves are of die cast material, expensive side action molds are required in addition to a single pull mold. The present invention is directed to solving these various problems by providing a new and improved interconnection system between a pair of shell halves in such a shielded electrical connector. 
     SUMMARY OF THE INVENTION 
     An object, therefore, of the invention is to provide an electrical connector with improved backshell halves which provide easy assembly and robust retention. 
     In the exemplary embodiment of the invention, an electrical connector assembly includes an inner connector defining a front-to-rear mating axis and including a plurality of conductive terminals. An outer shell is provided about the inner connector and includes a pair of backshell halves. Each backshell half includes a latch bar extending radially of the mating axis and a latch arm extending axially of the mating axis. The latch bar and the latch arm are at opposite sides of the backshell half and are constructed to be complementarily engageable so that the axially extending latch arm of one backshell half is engaged with the radially extending latch bar of the other backshell half to latch the backshell halves together and form the outer shell about the inner connector. 
     In the preferred embodiment, the backshell halves are hermaphroditic. The backshell halves preferably are fabricated of die cast metal material, such as a zinc alloy. 
     According to one aspect of the invention, the connector assembly includes a front shell around a front mating end of the inner connector. The backshell halves include front portions embracing at least a portion of the front shell. As disclosed herein, the front portions of the backshell halves are enlarged to define cavity halves which combine to define an enlarged shell cavity for embracing the front shell. 
     According to another aspect of the invention, a pair of jack screws are journalled in the outer shell for securing the electrical connector assembly to a mating connecting device. Each backshell half includes a pair of journal portions at the opposite sides thereof, whereby the latched backshell halves combine to form a pair of journal structures for the pair of jack screws at opposite sides of the outer shell. The latch bar and the latch arm of the backshell halves are formed on the journal portions. 
     According to a further aspect of the invention, fastening means are provided rearwardly of the latch bars and the latch arms to hold the backshell halves about the inner connector. As disclosed herein, the fastening means comprise a pair of fasteners, such as bolts, at the opposite sides of the backshell halves. 
     Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: 
     FIG. 1 is a front perspective view of an electrical connector assembly embodying the concepts of the invention; 
     FIG. 2 is a view similar to that of FIG. 1, with the top backshell half removed from the remainder of the connector assembly; 
     FIG. 3 is an exploded perspective view showing the components of the connector assembly; 
     FIG. 4 is a perspective view looking at the inside of one of the hermaphroditic backshell halves; 
     FIG. 5 is a fragmented perspective view looking at the latching area between the backshell halves which form the front journal for one of the jack screws; 
     FIG. 6 is a fragmented perspective view looking at the front of the same area as FIG. 5, but at the opposite side of the connector assembly; and 
     FIG. 7 is a view somewhat similar to that of FIG. 2, but showing the top backshell half in the process of being assembled to the bottom backshell half about the inner connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in greater detail, and first to FIGS. 1-3, the invention is embodied in an electrical connector assembly, generally designated  10  (FIG.  1 ), which includes an inner connector, generally designated  12  (FIGS.  2  and  3 ), surrounded by an outer shell, generally designated  14  (FIG.  1 ). The outer shell is provided by a pair of backshell halves, generally designated  16 , along with a front shell, generally designated  18 . In the preferred embodiment, backshell halves  16  are hermaphroditic and are fabricated of die cast material, such as a zinc alloy. 
     As best seen in FIG. 3, inner connector  12  includes a dielectric wire management plate  20  having a front housing portion  22  which mounts a plurality of conductive terminals, generally designated  24 . The terminals have forwardly projecting pin portions  24   a  and rearwardly projecting tail portions  24   b  which are properly spaced on wire management plate  20 . A front pin aligner  26  of dielectric material is positioned over terminal pin portions  24   a  which extend through passages  26   a  in the pin aligner. The pin aligner is snappingly engaged with housing portion  22  of wire management plate  20  by means of a pair of top and bottom latch bosses  28  on the housing portion snapping into a pair of latch openings  30  on both the top and bottom of the pin aligner. 
     A composite electrical cable  32  includes a plurality of electrical wires  34 . Each electrical wire includes a plurality of discrete conductors  36 . The conductors are electrically connected, as by soldering, to tail portions  24   b  of terminals  24 . Alternatively, wire management plate  20  could be a circuit board, with conductors  36  connected, as by soldering, to circuit traces on the board which, in turn, are connected to terminal tails  24   b.  Inner connector  12  effectively defines a front-to-rear mating axis  38  which is generally coincident with the longitudinal central axis of electrical cable  32 . 
     Front shell  18  of electrical connector assembly  10  is fitted over the front mating end of inner connector  12  as seen best in FIG.  2 . The front shell includes an enlarged rear portion  18   a  which is sized to fit over dielectric pin aligner  26  of the inner connector. A smaller front portion  18   b  of the front shell forms a shroud which completely surrounds terminal pins  24   a  as can be seen in FIG.  2 . Therefore, when connector assembly  10  is mated with a complementary mating connector (i.e., terminal pins  24   a  are inserted into complementary female terminals), front shell  18  will surround the mating interface between the connectors. The front shell is attached to pin aligner  26  by means of a pair of latch bosses  40  on both the top and bottom of the pin aligner snap-latchingly engaging within a pair of latch apertures  42  in both the top and bottom of enlarged rear portions  18   a  of front shell  18 . 
     Before proceeding with a description of backshell halves  16 , FIGS. 1-3 show that the backshell halves, when interengaged as seen in FIG. 1, journal a pair of jack screws  46 . As is known in the art, the jack screws have serrated enlarged heads  46   a  at the rear ends thereof for manual grasping and rotating the jack screws. In addition, heads  46   a  may have slots  46   b  for receiving an appropriate tool, such as a screwdriver, for rotating the jack screws. The front distal ends  46   c  of the jack screws are externally threaded. Finally, the particular jack screws shown herein have radially projecting ring portions  46   d  at a particular location inwardly of heads  46   a.  In certain applications, the mating connector which mates with inner connector  12  is mounted in a panel, such as the rear panel of a computer or other appliance. Jack screws  46  are used to thread distal ends  46   c  into appropriate holes in the panel to secure connector assembly  10  to the panel in mating condition with the complementary mating connector. Alternatively, the jack screws could be threaded directly into a complementary mating connector. 
     Referring to FIG. 4 in conjunction with FIGS. 1-3, each hermaphroditic backshell half  16  includes a generally flat body  48  which has a pair of positioning ribs  48   a  and  48   b  at opposite sides thereof. A positioning groove  48   c  is formed outside positioning rib  48   b.  When the hermaphroditic backshell halves are assembled to each other, positioning rib  48   b  of one backshell is positioned inside positioning rib  48   a  of the other backshell half, and positioning rib  48   a  of the other backshell half moves into positioning groove  48   c  of the one backshell half. 
     Each hermaphroditic backshell half  16  includes a strain relief portion  50  projecting rearwardly of body portion  48  and die cast integrally therewith. A plurality of transversely extending strain relief ribs  50   a  clamp onto the outside of electrical cable  32  when the backshell halves are assembled as seen in FIG.  1 . Generally, fastening means are provided at the rear of the backshell halves to securely hold the backshell halves in assembly. Specifically, a free hole  50   d  is formed in a laterally extending boss  50   c  at one side of the backshell half as seen clearly in FIG. 4. A pair of diametrically opposite recesses  50   d  are formed at opposite front-to-rear sides of free hole  50   b.  A hole  50   e  is formed in another boss  50   f  projecting from the opposite side of the backshell half. A pair of positioning tabs  50   g  are located at opposite front-to-rear sides of hole  50   e.  When the backshell halves are assembled, positioning tabs  50   g  of one backshell half enter recesses  50   d  of the other backshell half, while free holes  50   b  of the respective backshell halves are aligned with holes  50   e.  Therefore, a pair of externally threaded bolts  52  (FIGS. 2 and 3) can be inserted through free holes  50   b  and threaded into holes  50   e  to securely hold the two backshell halves in assembly. 
     Still referring particularly to FIG. 4 in conjunction with FIGS. 1-3, the invention contemplates a unique latching system to latch hermaphroditic backshell halves  16  in assembly. Specifically, a latch bar  54  extends outwardly from one side of each backshell half at the front end thereof. A latch arm  56  extends forwardly of the backshell half at the opposite side thereof. In essence, latch bar  54  extends radially outwardly of mating axis  38  of the connector assembly, and latch arm  56  extends axially forwardly, generally parallel to the mating axis. With the backshell halves being fabricated of die cast metal material, it can be seen in FIG. 4 that latch bar  54  and latch arm  56  can be made thick and quite robust and not susceptible to breakage. The entire structure of backshell halves  16  allow each backshell half to be die cast by two simple separable molds. 
     FIGS. 5 and 6 show different perspective views of how latch arm  56  is formed sort of circumferentially and then extends forwardly to overlap a back side of latch bar  54 . This interengagement prevents the backshell halves from separating out of assembly in the direction of double-headed arrows “A”. 
     As best seen in FIGS. 3 and 4, the front end of each backshell half is provided with a cavity half  58  which, when the backshell halves are assembled, combine to define an enlarged shell cavity for embracing enlarged rear portion  18   a  (FIG. 3) of front shell  18 . This further facilitates holding the entire assembly together. 
     Each backshell half includes a pair of jack screw journal halves  60  at opposite sides thereof intermediate opposite front and rear ends of the backshell half. When the backshell halves are assembled as seen in FIG. 1, journal halves  60  combine to form holes  62  through which jack screws  46  are journalled intermediate opposite ends of the connector assembly. FIG. 2 shows that enlarged rings  40   d  of the jack screws are located within journal halves  60 , but the rings are larger in diameter than hole  62 . Therefore, the rings can abut opposite ends or sides of the interior of the journal halves to define front and rear limit positions of the jack screws axially thereof. 
     A pair of jack screw journal halves  66  also are formed at opposite sides of each backshell half  16  at the very front thereof. When the backshell halves are assembled as shown in FIG. 1, journal halves  66  define holes  68  through which the front externally threaded distal ends  46   c  of the jack screws extend. 
     FIGS. 1,  5  and  6  show a significant feature of the invention wherein latch bars  54  and latch arms  56  are formed at the outer surfaces of front journal halves  66  for jack screws  46 . This saves considerable axial space on the jack screw halves and thereby shortens the entire connector assembly. In other words, the latching system provided by latch bars  54  and latch arms  56  are not located at separate axial locations from front journals  66  for the jack screws. 
     Finally, FIG. 7 shows how backshell halves  16  are assembled by interengaging latch bars  54  and latch arms  56 . During assembly, inner connector  12  is terminated to electrical cable  32 , front shell  18  and jack screws  46  are assembled into one of the backshell halves as seen best in FIG.  2 . The second or top backshell half then is positioned as shown in FIG. 7 so that latch bar  54  of the top backshell half interengages beneath latch arm  56  of the bottom backshell half. This can be accomplished by cocking the top backshell half as seen in FIG.  7  and slightly lowering the backshell half. Once latch bar  54  of the top backshell half is aligned with latch arm  56  of the bottom backshell half, the top backshell half then is rotated downwardly and forwardly so that latch arm  56  moves in the direction of arrow “B” to a position beneath latch bar  54  of the bottom backshell half. Once the backshell halves are assembled and securely latched at the front ends thereof by latch bars  54  and latch arms  56 , fastening bolts  52  are used at the rear of the backshell halves to completely hold the backshell halves in the final assembly of electrical connector assembly  10 . 
     It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.