Patent Publication Number: US-6663415-B1

Title: Electrical connector assembly with improved strain relief

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is related to U.S. Pat. application with an unknown Serial number, filed on Jul. 30, 2002 and entitled “ELECTRICAL CONNECTOR HAVING A LATCH MECHANISM”, which is assigned to the common assignee and which is hereby fully incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector assembly, and particularly to an electrical connector assembly with an improved strain relief for firmly securing a cable attached thereto. 
     2. Description of Related Art 
     When a cable or the like is terminated by an electrical connector, strain relief means are needed to minimize forces put (exerted) on the connections between the cable and the connector. Strain relief of a cable terminated to a connector requires proper compression of the cable and holds the cable firmly. 
     Referring to U.S. Pat. No. 4,842,547 issued to Defibaugh, et al. on Jun. 27, 1989, a strain relief  30  has a bight  52  and two legs  54 ,  56  extending therefrom to respective free ends thereof. Each leg  54 ,  56  include a plurality of barbs  66  formed on opposite edges thereof. As the strain relief  30  is inserted into a connector housing  12  to a predetermined position, the cable  36  is compressed into a remaining space between the strain relief  30  and an abutment surface  32  of the connector housing  12 . The barbs  66  are in penetrating contact with engagement surfaces  42 ,  44  of the connector housing  12 . However, the mount of the compression force is difficult to control. When the compression force is too small, the cable may rotate and easy to be pulled out of the connector housing  12 . 
     U.S. Pat. No. 5,383,796 issued to Bowen, et al. on Jan. 24, 1995 discloses another design of a strain relief. Bowen discloses a cable strain relief  56  includes a center section  60  adapted to embrace one side of a cable, and a pair of wing sections  62  extending from the center section  60  and having screw-receiving holes  58  in align with screw posts  38  defined on a connector housing  18 . A pair of screw posts  50  assembles to the screw posts  38  and the screw-receiving holes  58  to secure the strain relief  56  and the cable. The Bowen design is relative complicated and this increases the cost of the whole connector. Moreover such design is unfit for high speed applications because it ignores Electro Magnetic Interference shielding of the cable. 
     It is thus desirable to provide an improved strain relief of an electrical connector assembly to alleviate or even eliminate the above-discussed problem. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an electrical connector assembly with an improved strain relief, the strain relief can provide enough retaining force on a cable for securing the cable to the electrical connector. 
     To achieve the above-mentioned object, an electrical connector assembly in accordance with the present invention comprises a base, a cover assembled to the base, a cable and a U-shaped strain relief. The base has a first opening at a rear end portion thereof. A pair of channels is defined on opposite sides of the first opening. A connector subassembly comprises an insulative housing received in a front end of the base, a plurality of terminals assembled into the housing. A printed circuit board (PCB) is assembled to the housing and electrically connecting with the terminals. The cover and the base together define an interior space. The cover has a second opening corresponding to the first opening of the base. The first and second openings together define a cable receiving opening. The cable is received in the interior space from the cable receiving opening and has a metal shield enclosing thereof. The strain relief has a bight, a pair of intermediate portions extending obliquely from opposite lateral sides of the bight, and a pair of legs extending downwardly from bottom ends of the intermediate portions. The bight and the intermediate portions each have a spring tab extending inwardly and electrically connect with the metal shield of the cable. Each leg has two rows of barbs formed on opposite edges thereof. The two legs are received in the channels of the base and the barbs interferentially engage with inner surfaces of the channels. 
    
    
     Other objects, advantages and novel features of the 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 perspective view of an electrical connector assembly in accordance with the present invention; 
     FIG. 2 is an enlarged perspective view of a base shown in FIG. 1; 
     FIG. 3 is an enlarged perspective view of a cover shown in FIG. 1 from a bottom aspect; 
     FIG. 4 is an enlarged perspective view of a strain relief shown in FIG. 1; 
     FIG. 5 is an assembled view of the electrical connector assembly shown in FIG. 1; 
     FIG. 6 is a view similar to FIG. 5, with the cover being removed; 
     FIG. 7 is a top view of FIG. 6; and 
     FIG. 8 is a cross-sectional view of the electrical connector assembly taken along a line  8 — 8  of FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, an electrical connector assembly  1  in accordance with the present invention comprises a base  10 , a cover  20  for assembled to the base  10 , a pair of screws  30  for securing the cover  20  on the base  10 , a cable  40 , a strain relief  50 , and a connector subassembly  60 . 
     Referring to FIG. 2, the base  10  comprises a base plate  11  and a pair of sidewalls  12  upwardly extending from opposite lateral sides of the base plate  11 . A mating frame  13  is formed on a front end portion  15  of the base  10 . The mating frame  13  defines a connector receiving opening  133  through the front end portion  15 . The base  10  has a first opening  17  at a rear end portion  14  which is opposite to the front end portion  15 . The first opening  17  is defined by a flat bottom wall  171  and a pair of inclined lateral walls  172  connecting opposite lateral ends of the bottom wall  171 . A plurality of wedges  174  extends from the bottom wall  171  and the pair of inclined lateral walls  172  into the first opening  17 . Front sides of the wedges  174  are higher than rear sides thereof. The rear end portion  14  defines a pair of vertical channels  173 , located on opposite lateral sides of the first opening  17 . The base  10  has a semicircular shaped flange  176  formed at a rear end of the rear end portion and adjacent to the first opening  17 . The flange  176  has two arc-shaped ribs  175  extending inwardly to the first opening  17 . 
     Referring to FIG. 3, the cover  20  comprises a cover plate  21  and a pair of sidewalls  22  downwardly extending from opposite sides of the cover plate  21 . The cover  20  has a second opening  27  at a rear end portion  24 . The second opening  27  is defined by a flat top wall  271  and a pair of inclined lateral walls  272  defined on the rear end portion  24 . The pair of inclined lateral walls  272  connects opposite lateral ends of the top wall  271 . The cover  20  has a semicircular shaped flange  276  formed at a rear end of the rear end portion  24  and adjacent to the second opening  27 . The flange  276  has two arc-shaped ribs  275  extending inwardly to the second opening  27 . A more detailed description of the base  10  and the cover  20  can be found in the co-pending application. 
     Referring to FIG. 4, the U-shaped strain relief  50  is typically made of electrical conductive material with high rigidity. The strain relief  50  has a bight  51 , a pair of intermediate portions  52  extending obliquely from opposite lateral sides of the bight  51  and at an angle of about 45° with the bight  51 , and a pair of legs  54  extending downwardly from bottom ends of the intermediate portions  52 . The bight  51  and the intermediate portions  52  each have a spring tab  53  punched inwardly. Each leg  54  has two rows of barbs  55  formed on front and rear edges thereof. 
     Referring to FIG. 1, the cable  40  comprises a plurality of insulated conductors  42  arranged together with a jacket  41  enclosing thereof. The insulated conductors  42  are exposed at one end of the cable  40 . A metal shield  43  encloses the jacket  41  adjacent to the exposed portions of the insulated conductors  42 . The metal shield  43  has an expended cycle portion  431  formed adjacent to the exposed portions of the insulated conductors  42 . 
     The connector subassembly  60  comprises an insulating housing  61 , a plurality of terminals  64  is received in the housing and a printed circuit board (PCB)  63  assembled to a rear end of the housing  61 . 
     Referring to FIGS. 5-8, in assembly, the housing  61  of the connector subassembly  60  is inserted into the mating frame  13  with the PCB  63  positioned between the sidewalls  12 . The cable  40  is assembled to the base  10  with the metal shield  43  positioned in the first opening  17  and the insulated conductors  41  electrically connecting with the PCB. The metal shield  43  engages with the wedges  174  and the ribs  176 . The expended cycle portion  431  is placed inner side of the rear end portion  14 . The strain relief  50  is assembled to the base with the two legs  54  inserted into the channels  173 . The barbs  55  engage with inner walls of the channels  173 . The bight  51  and the pair of intermediate portions  52  cover on the metal shield  43  with the spring tabs  53  in contact with the metal shield  43 . The cover  20  is assembled to the base  10  with the strain relief  50  received into the second opening  27 . The bight  51  and the pair of intermediate portions  52  are respectively in contact with the flat top wall  271  and the pair of inclined lateral walls  272 . The ribs  175 ,  275  abut against rear end of the metal shield  43 . The screws  30  are assembled to the cover  20  and the base  10  to secure the cable  40  and the strain relief  50  in the cover  20  and the base  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.