Abstract:
A shielding terminal has a lock ( 14 ) mounted in an area extending from an opening ( 22 ) of a covering wall ( 21 ) to an outer crimping portion ( 23 ) of an outer terminal ( 12 ), and is fixed with respect to the outer terminal ( 12 ) by mounting plates ( 41 ) wrapping around the outer crimping portion ( 23 ). At this stage, a locking edge ( 45 ) at the leading end of the lock ( 14 ) faces a bottom end of the rear end of a connecting portion ( 15 ) of an inner terminal ( 11 ) so as to be engageable therewith for locking. Accordingly, even if the inner terminal ( 11 ) tries to come out of a dielectric element ( 13 ) upon action of a pulling force on a core ( 2 ) of a shielded cable ( 1 ), the rear end of the connecting portion ( 15 ) comes into contact with the locking edge ( 45 ) of the lock ( 14 ) to prevent such a movement.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a shielding terminal to be connected with an end of a shielded cable and to a method for mounting a shielding terminal to an end of a shielded cable.  
           [0003]    2. Description of the Related Art  
           [0004]    A known shielding terminal is illustrated in FIGS. 8 and 9 and has an inner terminal “a” for connection with a mating terminal, an outer terminal “c” that accommodates the inner terminal “a” and a dielectric element “b” provided between the inner and outer terminals “a” and “c”. The inner terminal “a” is crimped into connection with an end of a core “e” of a shielded cable “d”, and the outer terminal “c”” is crimped into connection with ends of a braided wire “f” and a sheath “g”.  
           [0005]    A shielding terminal of the type shown in FIGS. 8 and 9 must have a large fastening force to the shielded cable “d” to prevent the shielded cable “d” from being detached from the shielding terminal in response to a pulling force on the shielded cable “d”. Conventionally, biting blades have been formed to project from the outer surface of the inner terminal “a”. The biting blades bite in the inner surface of the dielectric element “b” to prevent the shielded cable “d” from being detached from the shielding terminal.  
           [0006]    The conventional shielding terminal has a groove formed behind the biting blades in the inner surface of the dielectric element. Thus, sufficient force to prevent the detachment may not be obtained due to a possible insufficient degree of engagement. Accordingly, there is a demand for a further improvement.  
           [0007]    The present invention was developed in view of the above situation and an object thereof is to provide a shielding terminal and a mounting method that achieve a larger fastening force of the shielding terminal to a shielded cable.  
         SUMMARY OF THE INVENTION  
         [0008]    The invention is directed to a shielding terminal that can be connected with an end of a shielded cable. The shielding terminal comprises an inner terminal for connection with a core of the shielded cable and an outer terminal for connection with a shield layer of the shielded cable. The outer terminal at least partly accommodates the inner terminal with a dielectric element provided between the inner and outer terminals. The shielding terminal further comprises a lock mountable in or on the outer terminal for preventing the inner terminal from coming out.  
           [0009]    A force may act to move the inner terminal out of the dielectric element, such as when the core is pulled. However, the inner terminal is locked in the outer terminal by the lock and is prevented from coming out of the dielectric element. Therefore, a fastening force to the shielded cable can be strengthened.  
           [0010]    A preferred embodiment of the shielding terminal is constructed for connection with an end of a shielded cable that comprises a core, an insulating layer surrounding the core, a braided wire surrounding the insulating layer and a sheath on the outer surface of the braided wire. The shielding terminal comprises an inner terminal to be connected with the core and an outer terminal to be connected with the braided wire. The outer terminal accommodates the inner terminal and a dielectric element that is provided between the inner and outer terminals. A lock is mounted in the outer terminal to prevent the inner terminal from coming out of the outer terminal. More particularly, an opening may be formed in part of a circumferential surface of the outer terminal, and the lock may be mounted at least partly in the opening. The lock mounted in the opening in the circumferential surface of the outer terminal prevents the shielding terminal from becoming larger.  
           [0011]    A shield plate may be mounted on or provided in the lock. The shield plate preferably is connectable with the shield layer and/or the outer terminal. A shielding performance can be improved by providing the shield plate in the opening where no shield member has been present.  
           [0012]    The lock preferably is formed with a locking edge that can be locked with a rear portion of the inner terminal, and preferably with a connection portion of the inner terminal.  
           [0013]    The lock preferably comprises latching means for latching the lock with the inner and/or outer terminals. The latching means may comprise hooks that engage at least one crimping portion of the outer terminal.  
           [0014]    The lock may comprise locking means for engagement with a sheath of the shielded cable and/or with the dielectric member.  
           [0015]    The invention also is directed to a method for mounting, assembling or connecting a shielding terminal with an end of a shield cable. The method comprises connecting an inner terminal with a core of the shielded cable. The method then comprises connecting an outer terminal with a shield layer of the shielded cable and at least partly accommodating the inner terminal with a dielectric element provided between the inner and outer terminals. The method then includes mounting a lock in or on the outer terminal for preventing the inner terminal from coming out.  
           [0016]    The lock preferably is mounted in an opening formed in part of a circumferential surface of the outer terminal.  
           [0017]    Preferably, a shield plate is mounted on or in the lock. The shield plate preferably is connected with the shield layer and/or the outer terminal. 
       
    
    
       [0018]    These and other objects, features and advantages of the present invention will become apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings.  
       BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is an exploded perspective view of one embodiment of the present invention.  
         [0020]    [0020]FIG. 2 is an exploded side view partly in section of this embodiment.  
         [0021]    [0021]FIG. 3 is a front view of a lock member.  
         [0022]    [0022]FIG. 3A is front view of an alternative to the lock shown in FIG. 3.  
         [0023]    [0023]FIG. 3B is a cross sectional view taken a long line  3 B- 3 B in FIG. 3A.  
         [0024]    [0024]FIG. 4 is a vertical section showing a mounting operation of the locking member.  
         [0025]    [0025]FIG. 5 is a vertical section showing an assembled state of a shielding terminal and a shielded cable.  
         [0026]    [0026]FIG. 6 is a rear view showing the assembled state.  
         [0027]    [0027]FIG. 7 is a bottom view showing the assembled state.  
         [0028]    [0028]FIGS. 8 and 9 are a perspective view and a plan view of a prior art shielding terminal connected with a shielded cable. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]    A female shielding terminal in accordance with the invention is identified by the numeral  10  in FIGS.  1 - 7 . The female shielding terminal  10  can be crimped, folded or bent into connection with an end of a shielded cable  1 . The shielded cable  1  has a known structure with a core  2  formed by bundling a plurality of strands. An insulating layer  3  surrounds the core  2 , and a shield layer, such as a braided wire  4  or a shield film surrounds the insulating layer  3 . A sheath  5  made of a rubber or the like surrounds the braided wire  4 , as shown in FIGS. 1 and 2. An end of the shielded cable  1  is processed by stripping off an end of the sheath  5 . The exposed section of the braided wire  4  then is folded back on the sheath  5 , and an exposed end of the insulating layer  3  is cut off to expose the core  2 .  
         [0030]    The shielding terminal  10  is comprised of an inner terminal  11 , an outer terminal  12 , a dielectric element  13  and a locking member  14 , as shown in FIGS. 1 and 2.  
         [0031]    The inner terminal  11  is formed by bending a metallic plate, and includes opposite front and rear ends. A substantially rectangular tubular female connecting portion  15  is formed at the front end, and transversely arranged inner crimping pieces  16  are formed behind the connecting portion  15  for crimped connection with the core  2  of the shielded cable  1 . Contact pieces  17  are formed at opposite side surfaces of the connecting portion  15 , and are configured for connection with a tab (not shown) of a mating male inner terminal. The contact pieces  17  cantilever forward and are bent so that facing surfaces at the leading ends of the contact pieces  17  bulge inwardly. The contact pieces  17  are resiliently or elastically deformable in directions that cause their leading ends to move toward and away from each other as the tab of the mating terminal is insertable therebetween.  
         [0032]    The bottom wall of the rear end of the connecting portion  15  is cut off, and one or more biting blades  18  are formed at the bottom edges of the left and right side walls near the rear end. The biting blades  18  bite in the bottom wall of the dielectric element  13  when the connecting portion  15  is pressed into the dielectric element.  
         [0033]    The outer terminal  12  also is formed by bending a metallic plate and has opposite front and rear ends. A large substantially rectangular tubular accommodating portion  20  is formed at the front end of the outer terminal  12 , and a covering wall  21  is formed rearward of the accommodating portion  20 . The covering wall  21  is closed on three sides, but has an open bottom. An outer crimping portion  23  is formed to the rear of the covering wall  21  and can be crimped, folded or bent into connection with a folded section of the braided wire  4  of the shielded cable  1 . The outer crimping portion  23  has two transversely arranged outer crimping pieces  24  that are wound or folded at least partly around the folded section of the braided wire  4  such that an end of one crimping piece  24  is placed substantially over the end of the other. The crimped outer crimping portions  23  have an arcuate upper surface with a small curvature, a substantially semicircular bottom surface, and substantially parallel left and right surfaces.  
         [0034]    Wedge-shaped projections  25  are formed at the base ends of the two outer crimping pieces  24  and on the outer crimping piece  24  which is placed more inside the other in its wound state. Further, stabilizers  26  project laterally outward from the bottom edges of the left and right side walls of the covering wall  21 .  
         [0035]    The dielectric element  13  is made of an insulating material, such as a synthetic resin, and electrically insulates the inner and outer terminals  11 ,  12  from each other. The dielectric element  13  has a shape that conforms to the inner and outer terminals  11 ,  12  and preferably is in the form of a substantially rectangular tube with a thick wall that can be fit into the front end of the accommodating portion  20  of the outer terminal  12 . An accommodating hole  28  is defined inside the dielectric element  13 , and is dimensioned to accommodate the connecting portion  15  of the inner terminal  11 . A flange  29  is formed at the front surface of the dielectric element  13  and can be brought into abutment against the front edge of the accommodating portion  20  of the outer terminal  12 . A terminal insertion opening  30  is defined at the front end of the accommodating hole  28  for receiving the tab of the mating terminal. Further, the lower half of the rear end of the dielectric element  13  is cut off to conform to the configuration of the accommodating portion  20  of the outer terminal  12 .  
         [0036]    A metal lock  32  is formed by cutting the upper surface of the accommodating portion  20  of the outer terminal  12  and bending the cut portion inward and obliquely backward. Additionally, a lock hole  33  is formed in the upper surface of the dielectric element  13  for receiving the metal lock  32  of the outer terminal  12 .  
         [0037]    The lock  14  is made e.g. of a synthetic resin and is mounted in an area that extends substantially from an opening  22  of the covering wall  21  of the outer terminal  12  to the outer crimping portion  23 . The lock  14  includes a narrow base plate  40  and has a front portion that is sufficiently narrow to be fit closely into the opening  22  of the covering wall  21  (see FIG. 7). Two mounting plates  41  project substantially normal to the opposite side edges of the rear end of the base plate  40 . The mounting plates  41  are formed to surround the crimped outer crimping portion  23  from its bottom surface to its left and right side surfaces. Hooks  42  extend inward at the upper ends of the mounting plates  41  and engage the left and right corners of the upper surface of the crimped outer crimping portion  23 . The mounting plates  41  are resiliently or elastically deformable such that their upper ends move toward and away from each other.  
         [0038]    The base plate  40  is thicker at the front end than at the rear end, and a locking step  44  is defined at the rear of the upper surface of the front end. The locking step  44  engages the end of the sheath  5  of the shielded cable  1  that is covered by the folded section of the braided wire  4  and engages the front part of the crimped outer crimping portion  23 .  
         [0039]    A front half of the front end of the base plate  40  is thinned in the widthwise center of its lower surface to form a gate. The upper edge of the front surface of this gate defines a locking edge  45  that is engageable with the bottom of the rear end of the connecting portion  15  of the inner terminal  11 . Further, left and right side edges  46  of the front surface of the gate engage edges left by cutting off the portions of the dielectric element  13  and the accommodating portion  20  of the outer terminal  12 , as shown in FIG. 5.  
         [0040]    Left and right side walls  48  stand from the left and right side edges of the front end of the base plate  40 , and a portion of an assembly of the inner terminal  11  and the shielded cable  1  from the end of the insulating layer  3  to the inner crimping pieces  16  can be accommodated between the side walls  48 .  
         [0041]    The end of the shielded cable  1  is processed as described above, and the inner crimping pieces  16  of the inner terminal  11  are crimped, folded or bent into connection with the end of the core  2 . The dielectric element  13  then is inserted into the accommodating portion  20  of the outer terminal  12  from the front. The insertion of the dielectric element  13  deforms the metal lock  32 . However, the metal lock  32  is restored resiliently toward its original shape to fit into the locking hole  33  when the flange  29  contacts the front edge of the accommodating portion  20 , as shown in FIG. 4. As a result, the dielectric element  13  is fixed at the front end of the accommodating portion  20 .  
         [0042]    Subsequently, the inner terminal  11  is inserted into the accommodating portion  20  of the outer terminal  12  from behind, and is pushed into the accommodating hole  28  of the dielectric element  13  that is fixed in the accommodating portion  20 . More particularly, the inner terminal  11  is pushed by a jig inserted through the opening  22  of the covering wall  21 . At this stage, the biting blades  18  press against and bite into the bottom wall of the accommodating hole  28 . As a result, the inner terminal  11  is partly locked.  
         [0043]    The outer crimping pieces  24  of the outer terminal  12  then are crimped and wound at least partly around the folded section of the braided wire  4  for fastened to the folded section of the braided wire  4  and the end of the sheath  5 . At this time, the projections  25  bite into the braided wire  4  to achieve a stronger fastening of the outer crimping pieces  24 .  
         [0044]    Finally, as indicated by the arrow in FIG. 4, the lock  14  is mounted in the area extending from the opening  22  of the covering wall  21  of the outer terminal  12  to the outer crimping portion  23 . More particularly, the opposite side walls  48  on the base plate  40  are inserted into the opening  22  of the covering wall  21 . Simultaneously, the opposite mounting plates  41  move along the crimped outer crimping portion  23  and widen the spacing between the opposed mounting plates  41 . When the side walls  48  are inserted sufficiently to contact the ceiling surface of the accommodating portion  20  of the outer terminal  12 , the hooks  42  of the mounting plates  41  pass the corners of the upper surface of the outer crimping portion  23 . Thus, the hooks  42  engage the corners of the upper surface of the outer crimping portion  23  and the mounting plates  41  are restored as shown in FIG. 6. Preferably simultaneously, the locking step  44  engages the end of the sheath  5  and the front part of the outer crimping portion  23 ; the rear edges of the side walls  48  engage the front end of the sheath  5 ; the left and right side edges  46  at the front surface of the gate engage the cut-off portions of the dielectric element  13  and the outer terminal  12  from behind; and the front ends of the side walls  48  engaged the rear end of the upper part of the dielectric element  13 .  
         [0045]    In this way, the lock  14  is fixed in the outer terminal  12  and will not move downward, forward or backward. Additionally, the lock  14  covers the opening  22  of the covering wall portion  21  of the outer terminal  12  and the outer crimping portion  23 .  
         [0046]    At this time, the locking edge  45  at the leading end of the lock  14  faces and lockingly engages the bottom end of the rear end of the connecting portion  15  of the inner terminal  11 . Thus, a pulling force on the core  2  of the shielded cable  1  is resisted by the engagement of the rear end of the connecting portion  15  with the locking edge  45  of the lock  14  to prevent the inner terminal  11  from coming out of the dielectric element  13 .  
         [0047]    As described above, a “double-locking construction” is realized by providing the lock  14  for locking the inner terminal  11  in the outer terminal  12 . This effectively prevents the inner terminal  11  from coming out of the dielectric element  13  and strengthens a fastening force to the shielded cable  1 .  
         [0048]    Further, the lock  14  is mounted mainly by being fitted in the opening  22  of the covering wall  21 . Thus, the lock  14  prevents the entire shielding terminal  10  from becoming larger despite the provision of the lock  14 , as shown in FIGS. 3A and 3B.  
         [0049]    The shielding performance of the terminal  10  can be improved by incorporating at least one shield into the lock  14 . The shield may be disposed at portions of the lock  14  that will engage the shield layer  4  of the shielded cable  1  and/or the outer terminal  12 . For example, a metal coating  47  can be applied to lower surface regions of the base plate  40 , outer surface regions of the mounting plates  41  and upper and outer surface regions of the hooks  42 . Thus, a continuous shielding will extend across the open bottom of the covering wall  21  and substantially continuously between the accommodating portion  20  and the crimping pieces  24 . Alternatively, a separate metal plate (not shown) can be insert molded into the lower portions of the lock  14  for extending across the open bottom of the covering wall  21 .  
         [0050]    The present invention is not limited to the above described and illustrated embodiments. For example, following embodiments are also embraced by the technical scope of the present invention as defined in the claims. Beside the following embodiments, various changes can be made without departing from the scope and spirit of the present invention as defined in the claims.  
         [0051]    If a metallic plate is mounted as a shield plate in the locking member and part thereof is electrically connected with the outer terminal or another shield wall, the shield plate can also be provided at the opening of the covering wall portion where no shield member has been present. As a result, shielding performance can be improved.  
         [0052]    Although the female shielding terminal is illustrated in the foregoing embodiment, the present invention is similarly applicable to male shielding terminals.