Patent Publication Number: US-6338652-B1

Title: Low profile cable connector with grounding means

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part application of the application Ser. No. 09/578,349 filed May 24, 2000, and a continuation-in-part application of the application Ser. No. 09/350,942 filed Jul. 9, 1999 now U.S. Pat. No. 6,139,363. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a low profile connector for terminating a flat ribbon coaxial multiconductor cable, and particularly to a low profile connector with a modular insert subassembly and a grounding device that is easy to assemble and which establishes a grounding path between a grounding bar attached to the coaxial multiconductor cable and a shield of the connector. 
     2. Brief Description of the Prior Art 
     It is well known by those skilled in the art that, particularly for high frequency communication, a coaxial cable connector is required to terminate a coaxial multiconductor cable in order to minimize crosstalk between constituent coaxial conductors. Grounding means is required in such a connector to ground the braided coaxial conductor shields. 
     As disclosed in U.S. Pat. No. 4,781,620, a conventional flat ribbon coaxial multiconductor cable connector provides a grounding bus which connects with the coaxial braidings which shield component conductors of the coaxial multiconductor cable. The grounding bus is further connected to grounding contacts of the connector, thereby preventing crosstalk between the conductors. However, the connector is difficult to assemble because the grounding bus has to be soldered to the coaxial braiding of each conductor and to the grounding contacts. The soldering process makes assembly more complicated than a simple mechanical engagement between the grounding bus and the grounding contacts. Furthermore, the grounding bus and the grounding contacts are partially insert molded in a carrier housing. The housing must be thick enough to protect the contacts from damage, which results in a connector having large dimensions. Moreover, U.S. Pat. No. 4,781,620 provides no outer shield and thus does indicate an electrical connection between the shield around the connector. 
     Hence, an improved electrical connector is required to overcome the disadvantages of the prior art. 
     BRIEF SUMMARY OF THE INVENTION 
     A first object of the present invention is to provide a flat ribbon coaxial multiconductor cable connector with a grounding means which is easy to assemble; 
     A second object of the present invention is to provide a low profile flat ribbon coaxial multiconductor cable connector; 
     A third object of the present invention is to provide a flat ribbon coaxial multiconductor cable connector which has a shield electrically mating with a grounding means interior to the cable connector to establish a grounding path therebetween. 
     To achieve the above-mentioned objects, a cable connector for terminating a coaxial multiconductor cable set includes a housing, a conductive shield surrounding the housing, an insert incorporating a plurality of terminals therein, and a grounding plate fixed between the housing and the insert. 
     The coaxial multiconductor cable set comprises a plurality of wires and a grounding bar electrically connected to a length of bared braiding of each wire. 
     The housing provides a body and a mating tongue extending forwardly from the body. The body includes a front wall, a pair of sidewalls, and a top wall, together defining an opening therebetween. A pair of opposite notches is defined in the top wall. The mating tongue defines a plurality of depressions and passageways respectively in opposite sides thereof in communication with the opening. 
     The shield has a pair of fingers stamped in an upper surface thereof. 
     The insert comprises an insulative base from which the conductive terminals project forwardly in a row. A groove is defined along a length of the base for inserting the grounding bar of the cable set into, thereby forming a subassembly of the insert and the coaxial multiconductor cable set. A plurality of recesses are formed in the base and intersecting the groove. Each wire is received in a respective recess and connects with a corresponding terminal. 
     The grounding plate provides a plurality of grounding pads extending forward from a strip thereof and a pair of arms extending rearward from the strip. 
     During assembly, the shield is first mounted to the housing. The grounding plate is then simultaneously inserted into the housing with the subassembly of the insert and the coaxial multiconductor cable set so that the grounding pads of the grounding plate extend into corresponding depressions of the housing and the terminals of the insert extend into corresponding passageways of the housing. The arms of the grounding plate are located above the insert, thereby allowing for engagement with the grounding bar secured in the insert. The fingers of the shield protrude through the notches of the top wall of the housing to contact the arms of the grounding plate, thereby establishing an electrical path from the shield to the grounding bar via the grounding plate. In addition, a bottom side of the insert is coplanar with a bottom side of the sidewalls of the housing, thereby functioning as a bottom wall of the housing. Therefore, the height of the cable connector is minimized. 
     Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of an electrical cable connector with a cable set in accordance with a first embodiment of the present invention; 
     FIG. 2 is a perspective view of a bottom of a housing of the cable connector of FIG. 1; 
     FIG. 3 is a partially assembled view of the cable connector of FIG. 1; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  of FIG. 3; 
     FIG. 5 is an assembled view of FIG. 1; 
     FIG. 6 is a cross-sectional view taken along line  6 — 6  of FIG. 5; 
     FIG. 7 is a perspective view of a bottom of a grounding plate in accordance with a second embodiment of the present invention; and 
     FIG. 8 is a perspective view of a bottom of a grounding plate in accordance with a third embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a cable connector assembly  100  of the present invention includes an electrical cable connector  1  and a flat ribbon coaxial multiconductor cable set  40 . The cable connector  1  comprises a dielectric housing  10 , a conductive shield  60  for shielding the housing  10 , a metal grounding plate  30 , and an insert  20  incorporating a plurality of conductive terminals  22  therein. 
     The coaxial multiconductor cable set  40  consists of a plurality of wires  401  and a conductive grounding bar  50 . Each wire  401  includes a core conductor  424  which is shielded by a braiding  420  (see FIGS.  4  and  6 ). A layer of insulation (not labeled) isolates the core conductor  424  from the respective braiding  420 . The grounding bar  50  electrically connects with the braidings  420 . Each wire  401  is striped at a distal end thereof to expose a length of the braiding  420  and a separate length of the core conductor  424 . Details of the cable set  40  are disclosed in a U.S. application titled “MICRO CONNECTOR ASSEMBLY AND THE METHOD OF MAKING THE SAME”, which was filed on Jul. 9, 1999 and has an application Ser. No. 09/350,942. The Ser. No. 09/350,942 application is incorporated herein by reference. 
     The housing  10 , further referring to FIG. 2, consists of an elongate body  11  and a mating tongue  18  extending forward from a front end of the body  11 . The body  11  includes a top wall  12 , a pair of sidewalls  13 , and a front wall  14 , with an opening  15  defined therebetween for accommodating the insert  20  and the grounding plate  30 . The top wall  12  has a pair of notches  121  in a rear edge proximate the sidewalls  13 . A step-shaped channel  131  is defined in an inner side of each sidewall  13  in communication with the opening  15 . The front wall  14  defines a plurality of holes  141  therethrough, each in communication with a corresponding passageway  181  defined in a lower side of the mating tongue  18  for extensions of the terminals  22 . A slit  143  is further defined in the front wall  14  in communication with the opening  15  and a plurality of depressions  183  defined in an upper side of the mating tongue  18 . A pair of indents  125  and blocks  135 , as shown in FIG. 1, is provided respectively on the top wall  12  and on the sidewalls  13  of the housing  10 . 
     The shield  60  provides a pair of fingers  62  stamped downwardly from a top side thereof. Each finger  62  forms an arcuate free end for resiliently and reliably pressing against the grounding plate  30 . A pair of cutouts  66  is defined in lateral sides of the shield  60 , and a pair of tongues  64  is stamped in the top side of the shield  60  proximate to corresponding cutouts  66 . A pair of tails  68  respectively extends from lateral rear edges of the shield  60  for latching the shield  60  to the housing  10 . 
     The insert  20  includes an elongate dielectric base  21 , from which the conductive terminals  22  forwardly extend in a row. The base  21  forms a row of projections  211  and a row of ribs  213  on an upper side thereof. Each projection  211  aligns with a rib  213  in a rear to front direction, whereby a recess  216  is defined between neighboring projections  211  and ribs  213 . A groove  215  lengthwise extends between the rows of projections  211  and ribs  213  and intersects the recesses  216  for receiving the grounding bar  50  of the coaxial multiconductor cable set  40  therein. The terminals  22  are arranged to align with and are exposed at respective recesses  216 . Step-shaped flanges  218  are formed on lateral sides of the base  21  of the insert  20 . 
     The grounding plate  30 , in a first embodiment shown in FIG. 1, has an elongate strip  31 , a pair of L-shaped arms  33  extending rearward from opposite ends of the strip  31 , and a plurality of grounding pads  35  extending forward from a front edge of the strip  31  at equal intervals. The grounding plate  30  is preferably planar. Each arm  33  has a contacting section  331  parallel to the strip  31  and defines a space  37  between the contacting section  331  and the strip  31 . It is noted that the space  37  is designed for preventing the bared core conductors  424  from inadvertently engaging with the grounding plate  30  when debris is carelessly left between the ribs  213 , which would cause a short circuit between the bared core conductors  424  and the grounding plate  30 . An embossment  332  is formed on an underside of each contacting section  331 . 
     The coaxial multiconductor cable set  40  is adapted to be assembled to the insert  20  to provide a subassembly  90  such that each wire  401  is retained in a corresponding recess  216  and each core conductor  424  is soldered to a corresponding terminal  22 . The grounding bar  50  fits in the groove  215  of the base  21 . 
     In assembly, the shield  60  is first mounted to enclose the housing  10  from a rear end of the housing  10  to a position where the tongues  64  and the cutouts  66  of the shield  60  respectively mate with the indents  125  and the blocks  135  of the housing  10 . The grounding plate  30  and the subassembly  90 , which consists of the insert  20  and the coaxial multicondutor cable set  40 , are simultaneously inserted into the opening  15  of the housing  10 , the grounding plate  30  being above the subassembly  90 , so that the terminals  22  of the insert  20  extend through the holes  141  into corresponding passageways  181 , the grounding pads  35  of the grounding plate  30  extend through the slit  143  into the depressions  183  of the mating tongue  18 , and the fingers  62  of the shield  60  press against the contacting sections  331  of the grounding plate  30  through the notches  121  of the housing  10 . Finally, the tails  68  of the shield  60  are inwardly bent to retain the insert  20  and the grounding plate  30  in the opening  15 . 
     FIGS. 3 and 4 clearly show an engagement between the grounding plate  30 , the insert  20 , and the housing  10 , the shield  60  being removed for simplicity. The grounding pads  35  extend into the depressions  183  of the mating tongue  18  for connection with grounding pins of a mating connector (not shown), and the arms  33  of the grounding plate  30  lie against the top wall  12  and the contacting sections  331  are received beneath corresponding notches  121 . Lateral front edges of the strip  31  of the grounding plate  30  abut against lateral rear sides of the front wall  14  of the housing  10  for positioning the grounding plate  30  in proper position. At the same time, the grounding plate  30  is positioned over the insert  20  such that the embossments  332  formed on the underside of the contacting sections  331  are brought into electrical connection with the grounding bar  50  fixed in the insert  20 . A grounding path from the braidings  420  of respective wires  401  through the grounding bar  50  to the grounding plate  30  is thus established to ground the braidings of the coaxial multiconductor cable set  40  to an external ground circuit. Since the grounding plate  30  is facilely inserted into the housing  10 , rather than insert molded, the assembly of the connector  1  is less complicated and less expensive. 
     Moreover, the flanges  218  of the insert  20  are fixed in the channels  131  of the sidewalls  13  while a bottom side  217  of the insert  20  flushes with bottom sides of the sidewalls  13 . The flat bottom side  217  of the insert  20  thus acts as the bottom of the housing  10 , thereby reducing the height of the cable connector  1 . 
     FIGS. 5 and 6 show the shield  60  enclosing the housing  10 . The fingers  62  of the shield  60  protrude through the notches  121  of the housing  10  to electrically and mechanically contact with the contacting sections  331  of the arms  33  of the grounding plate  30 . The shield  60  is, therefore, grounded through the grounding plate  30  with the grounding bar  50  and the braidings  420  of the wires  401 . 
     FIG. 7 shows a perspective view of a bottom of a grounding plate  70  in accordance with a second embodiment, which includes an inclined strip  731 , a pair of arms  733  projecting rearward respectively from opposite ends of the strip  731 , and a plurality of grounding pads  735  forward extending from a front edge of the strip  731  at equal intervals. The strip  731  interconnects the arms  733  with the grounding pads  735 . Like the first embodiment, each arm  733  provides an embossment  732  on an underside thereof for reliably engaging with the grounding bar  50  when the grounding plate  70  is mounted between the insert  20  and the housing  10 . 
     In a third embodiment shown in FIG. 8, the grounding plate  80  provides a pair of arms  833  and a plurality of grounding pads  835  respectively extending from opposite edges of a strip  831 . A protrusion  832  connects a free end of each arm  833  with the strip  831  for touching the grounding bar  50  when the grounding plate  80  is mounted between the insert  20  and the housing  10 . 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.