A shielding terminal and a mounting method therefore

Abstract: [Object] To further strengthen a fastening force of a shielding terminal to a shielded cable. [Solution] A locking member 14 is mounted in an area extending from an opening 22 of a covering wall portion 21 to an outer crimping portion 23 of an outer terminal 12, and is fixed with respect to the outer terminal 12 so as not to come out downward and move forward and backward by mounting plates 41 wrapping around the outer crimping portion 23. At this stage, a locking edge 45 at the leading end of the locking member 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 locking member 14 to prevent such a movement.

Description: The present invention relates to a shielding terminal to be connected with an end of a shielded cable and to a mounting method therefor. A shielding terminal shown in FIGS. 8 and 9 is known as a shielding terminal of this type. This terminal is provided with an inner terminal "a" to be connected with a mating terminal and an outer terminal "c" accommodating the inner terminal "a" with a dielectric element "b" provided therebetween. 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". Such a construction is disclosed in Japanese Unexamined Utility Model Publication No. 5-27983 and other publications. It is one of essential points for the shielding terminal of this type to have a large fastening force to the shielded cable "d" in order to prevent the shielded cable d" from being detached from the shielded terminal when a pulling force acts on the shielded cable "d". Conventionally, biting blades have been formed to project from the outer surface of the inner terminal "a" to prevent such a detachment by causing the biting blades to bite in the inner surface of the dielectric element "b". US 5,624,278 discloses an electric wire connector having an insulating member which has a through hole running in the axial direction and a transverse hole provided between exterior and the through hole in a different direction from the axis of the through hole, a contact which is inserted in the through hole and which has a fitting structure in a position matching an inside opening, i.e. the opening on the through hole side of the transverse hole and a position restricting member which is inserted through an outside opening, i.e. the opening on the outer side of the transverse hole to be fitted in the fitting structure of the contact to restrict the position of the contact. EP 0 981 180 discloses a shielded connector, wherein a rear opening, for putting a shielded wire through, of a shielding terminal is closed so as to improve electrical shield. The shielded connector includes: an inner terminal connected to an inner conductor of a shielded wire with a shielding member; an inner housing to accommodate the inner terminal; a shielding terminal to cover the inner housing and to be connected to the shielding member of the shielded wire; an outer housing to accommodate the shielding terminal; a lid member provided at a rear opening of the shielding terminal integrally therewith through a hinge; and a pressure contact portion formed on the lid member so as to press the shielding member of the shielded wire, wherein the inner terminal is electrically shielded. The shielded connector further includes a spacer having an engaging plate to lock the shielding terminal to the outer housing, which engaging plate has a pressing portion to press the lid member on the shielding member of the shielded wire. However, in conventional shielding terminals, a groove is formed behind the biting blades biting in the inner surface, and no sufficient force to prevent the detachment can be obtained due to a possibly insufficient degree of engagement. Thus, there is a demand for a further improvement. 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 allowing for a larger fastening force of the shielding terminal to a shielded cable. This object is solved according to the invention by a shielding terminal according to claim 1 and by a method for mounting a shielding terminal according to claim 8. Preferred embodiments of the invention are subject of the dependent claims. According to the invention, there is provided a shielding terminal to be connected with an end of a shielded cable, comprising: an inner terminal to be connected with a core of the shielded cable, an outer terminal to be connected with a shield layer of the shielded cable while at least partly accommodating the inner terminal with a dielectric element provided between the inner and outer terminals, and a locking member mountable in or on the outer terminal for locking the inner terminal so as not to come out, where the locking member comprises latching means for latching the locking member with the inner and/or outer terminals. Even if a force acts to move the inner terminal to come out of the dielectric element such as when the core is pulled, the inner terminal is locked by the locking member mounted in the outer terminal, thereby being effectively prevented from coming out of the dielectric element. Therefore, a fastening force to the shielded cable can be strengthened. According to a preferred embodiment of the invention, there is provided a shielding terminal to be connected with an end of a shielded cable formed by concentrically arranging a core and a braided wire with an insulating layer provided therebetween and covering the outer surface of the braided wire by a sheath, comprising: an inner terminal to be connected with the core, an outer terminal to be connected with the braided wire while accommodating the inner terminal with a dielectric element provided between the inner and outer terminals, and a locking member mounted in the outer terminal for locking the inner terminal so as not to come out. Preferably, an opening is formed in part of a circumferential surface of the outer terminal, the locking member at least partly being mounted or mountable in the opening. Since the locking member is mounted in the opening formed in the circumferential surface of the outer terminal, it prevents the shielding terminal from becoming larger. Further preferably, a shield plate is mounted on or provided in the locking member, the shield plate being preferably 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. Further preferably, the locking member is formed with a locking edge being engageable for locking with a rear portion of the inner terminal, preferably of a connection portion thereof. Further preferably, the latching means comprise hooking portions engageable with at least one crimping portion of the outer terminal. Most preferably, the locking member comprises a locking means for coming into engagement with a sheath of the shielded cable and/or with the dielectric member. According to the invention, there is further provided a method of mounting or assembling or connecting a shielding terminal, in particular according to the invention or an embodiment thereof, with an end of a shield cable, comprising the following steps: connecting an inner terminal with a core of the shielded cable, connecting an outer terminal with a shield layer of the shielded cable while at least partly accommodating the inner terminal with a dielectric element provided between the inner and outer terminals, and mounting a locking member in or on the outer terminal for locking the inner terminal so as not to come out, the method further comprising the step of latching the locking member, which comprises latching means, with the inner and/or outer terminals. According to a further preferred embodiment of the invention, the locking member is mounted in an opening formed in part of a circumferential surface of the outer terminal. Preferably, a shield plate is mounted on or provided in the locking member, the shield plate being preferably connected with the shield layer and/or the outer terminal. 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 in which: FIG. 1 is an exploded perspective view of one embodiment of the present invention, FIG. 2 is an exploded side view partly in section of this embodiment, FIG. 3 is a front view of a locking member, FIG. 4 is a vertical section showing a mounting operation of the locking member, FIG. 5 is a vertical section showing an assembled state of a shielding terminal and a shielded cable, FIG. 6 is a rear view showing the assembled state, FIG. 7 is a bottom view showing the assembled state, and FIGS. 8 and 9 are a perspective view and a plan view of a prior art shielding terminal connected with a shielded cable. Hereinafter, one embodiment of the present invention is described with reference to FIGS. 1 to 7. In this embodiment is shown a female shielding terminal 10, which is used by being crimped or folded or bent into connection with an end of a shielded cable 1. The shielded cable 1 has a known structure, i.e. a core 2 e.g. formed by bundling a plurality of strands, an insulating layer 3, a shield layer such as a braided wire 4 or a shield film (not shown) and a sheath 5 e.g. made of a rubber or the like are concentrically arranged in this order from the innermost side as shown in FIGS. 1 and 2. In this embodiment, an end of the shielded cable 1 is processed by stripping an end of the sheath 5 off, at least partly folding the thus exposed section of the braided wire 4 substantially back on the sheath 5, and cutting an exposed end of the insulating layer 3 off to at least partly expose the core 2. 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. The inner terminal 11 is formed into a female terminal e.g. by bending a metallic plate, a connecting portion 15 preferably in the form of a substantially rectangular tube is formed at its leading end side, and a pair of transversely arranged inner crimping pieces 16 to be crimped or folded or bent into connection with the core 2 of the shielded cable 1 are formed behind or adjacent to the connecting portion 15. A preferably pair of left and right resilient or elastic contact pieces 17 to be connected with a tab (not shown) of a mating male inner terminal are formed at the left and right side surfaces of the connecting portion 15. The preferably two elastic contact pieces 17 cantilever forward and are bent so that the facing surfaces thereof at the leading end bulge out inwardly. They are resiliently or elastically deformable in such directions that their leading ends move toward and away from each other, and the tab of the mating terminal is insertable therebetween. The bottom wall of the rear end of the connecting portion 15 is cut off, and one or more biting blades or tooth or projections 18 are formed at the bottom edges of the left and side walls of this rear end. When the dielectric element 13 is at least partly pressed in, these biting blades 18 bite in the bottom wall thereof. The outer terminal 12 is likewise formed e.g. by bending a metallic plate and is comprised of an accommodating portion 20 in the form of a large substantially rectangular tube, a covering wall portion 21 whose walls are substantially closed except the bottom wall, and an outer crimping portion 23 to be crimped or folded or bent into connection with a folded section of the braided wire 4 of the shielded cable 1. The portions 20, 21, 23 are formed in this order from the leading end side. The outer crimping portion 23 is provided with a pair of transversely arranged outer crimping pieces 24, which are at least partly wound or folded on or around the folded section of the braided wire 4 preferably such that an end of one crimping piece 24 is placed substantially over that of the other. The crimped outer crimping portion 23 has an upper surface which is an arcuate surface having a small curvature, a bottom surface which is substantially semicircular, and left and right surfaces substantially parallel to each other. 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 portion 21. The dielectric element 13 is made of an insulating material such as a synthetic resin, and acts to electrically insulate the inner and outer terminals 11, 12 from each other. The dielectric element 13 has a shape mating or conforming to the inner and outer terminals 11, 12 and preferably is in the form of a substantially rectangular tube having a thick wall and fittable into the front end of the accommodating portion 20 of the outer terminal 12, and an accommodating hole 28 into which the connecting portion 15 of the inner terminal 11 is to be at least partly accommodated is defined inside the dielectric element 13. A flange 29 to be brought into abutment against the front edge of the accommodating portion 20 of the outer terminal 12 is formed at the front surface of the dielectric element 13, and a terminal insertion opening 30 into which the tab of the mating terminal is to be inserted is defined at the front end of the accommodating hole 28. Further, a lower half of the rear end of the dielectric element 13 is cut off so as to conform to the configuration of the accommodating portion 20 of the outer terminal 12. A metal locking portion 32 is formed in the upper surface of the accommodating portion 20 of the outer terminal 12 preferably by making a cut in the upper surface and bending a cut portion inward in such a manner as to extend obliquely backward, whereas a locking hole 33 into which the metal locking portion 32 of the outer terminal 12 is fittable is formed in the upper surface of the dielectric element 13. The locking member 14 is made e.g. of a synthetic resin material and mounted in an area substantially extending from an opening 22 of the covering wall portion 21 of the outer terminal 12 to the outer crimping portion 23. The locking member 14 includes a base plate 40 which is substantially narrow in forward and backward or longitudinal directions and whose front portion is so narrowed as to be substantially closely fitted or fittable into the opening 22 of the covering wall portion 21 (see FIG. 7). A pair of mounting plates 41 project at angle different from 0° or 180°, preferably substantially normal to or stand up from the opposite side edges of the rear end of the base plate 40. The mounting plates 41 are so formed as to substantially surround the crimped outer crimping portion 23 from its bottom surface to its left and right side surfaces, and hooking portions 42 engageable with the left and right corners of the upper surface of the crimped outer crimping portion 23 are formed at the upper ends of the mounting plates 41 preferably by bending. The mounting plates 41 are resiliently or elastically deformable such that their upper ends move toward and away from each other. On the other hand, a front end portion of the base plate 40 is formed to be thicker than a rear end portion, and the rear end of the upper surface of this front end portion is stepped to form a stepped portion which serves as a locking step 44 for coming into engagement with the end (covered by the folded section of the braided wire 4) of the sheath 5 of the shielded cable 1 and the front part of the crimped outer crimping portion 23. A front half of the front end portion of the base plate 40 is substantially thinned in the widthwise center of its lower surface to form a gate portion. The upper edge of the front surface of this gate portion serves as a locking edge 45 engageable with the bottom end 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 portion are engageable with the edges of the lower surfaces of the dielectric element 13 and the accommodating portion 20 of the outer terminal 12 which edges are left by cutting off the portions of the dielectric element 13 and the accommodating portion 20. A pair of left and right side walls 48 stand from the left and right side edges of the front end portion 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 at least partly accommodated between the two side walls 48. Next, the function of this embodiment is described. The shielding terminal 10 is connected with the end of the shielded cable 1 in a following procedure. The end of the shielded cable 1 is processed as described above. First, the inner crimping pieces 16 of the inner terminal 11 are crimped or folded or bent into connection with the end of the core 2. Then, the dielectric element 13 is at least partly inserted into the accommodating portion 20 of the outer terminal 12 preferably from front. The dielectric element 13 is pushed in while resiliently or elastically deforming the metal locking portion 32, which is elastically restored preferably substantially to its original shape to fit into the locking hole 33 when the flange 29 comes into contact with the front edge of the accommodating portion 20 as shown in FIG. 4, with the result that the dielectric element 13 is fixed at the front end of the accommodating portion 20. Subsequently, the inner terminal 11 is at least partly 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 fixed in the accommodating portion 20 by catching the inner terminal 11 using a jig inserted through the opening 22 of the covering wall portion 21. At this stage, the biting blades 18 are pressed against the bottom wall of the accommodating hole 28 to bite therein. As a result, the inner terminal 11 is partly locked. Then, the outer crimping pieces 24 of the outer terminal 12 are crimped and at least partly wound around or on the folded section of the braided wire 4, thereby being fastened to the folded section of the braided wire 4 and the end of the sheath 5. At this time, the outer crimping pieces 24 are more strongly fastened by the projections 25 biting in the braided wire 4. Finally, as indicated by an arrow of FIG. 4, the locking member 14 is mounted in the area extending from the opening 22 of the covering wall portion 21 of the outer terminal 12 to the outer crimping portion 23. More specifically, when the opposite side walls 48 on the base plate 40 are inserted into the opening 22 of the covering wall portion 21, the opposite mounting plates 41 are moved along the crimped outer crimping portion 23 while widening a spacing therebetween. When the side walls 48 are inserted to such a degree as to come into contact with the ceiling surface of the accommodating portion 20 of the outer terminal 12, the hooking portions 42 of the mounting plates 41 pass the corners of the upper surface of the outer crimping portion 23, whereby the hooking portions 42 are engaged with the corners of the upper surface of the outer crimping portion 23 while the mounting plates 41 are restored as shown in FIG. 6. Preferably simultaneously, the locking step 44 is engaged with the end of the sheath 5 and the front part of the outer crimping portion 23; the rear edges of the side walls 48 are engaged with the front end of the sheath 5; the left and right side edges 46 at the front surface of the gate portion are engaged with the cut-off portions of the dielectric element 13 and the outer terminal 12 from behind; and/or the front ends of the side walls 48 are engaged with the rear end of the upper part of the dielectric element 13. In this way, the locking member 14 is fixed in the outer terminal 12 so as not to come out downward and move forward and backward while covering the opening 22 of the covering wall portion 21 of the outer terminal 12 and the outer crimping portion 23. At this time, the locking edge 45 at the leading end of the locking member 14 faces the bottom end of the rear end of the connecting portion 15 of the inner terminal 11 so as to be engageable therewith for locking. Thus, even if the inner terminal 11 tries to come out of the dielectric element 13 upon action of a pulling force on the core 2 of the shielded cable 1, such a movement is hindered by the engagement of the rear end of the connecting portion 15 with the locking edge 45 of the locking member 14. As described above, according to this embodiment, a so-called "double-locking construction" is realized by providing the locking member 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. Further, since the locking member 14 is mounted mainly by being fitted in the opening 22 of the covering wall portion 21, it prevents the entire shielding terminal 10 from becoming larger despite additional provision of the locking member 14. 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. (1) 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 an other shield wall, the shield plate can also be provided at the opening of the covering wall portion where no shield member has been present, with the result that a shielding performance can be improved. (2) Although the female shielding terminal is illustrated in the foregoing embodiment, the present invention is similarly applicable to male shielding terminals. LIST OF REFERENCE NUMERALS 1 shielded cable 2 core 3 insulating layer 4 braided wire 5 sheath 10 shielding terminal 11 inner terminal 12 outer terminal 13 dielectric element 14 locking member 15 connecting portion 21 covering wall portion 22 opening (of the covering wall portion) 23 outer crimping portion 41 mounting plate 42 hooking portion 45 locking edge 46 side edge 48 side walls

Claims: A shielding terminal (10) to be connected with an end of a shielded cable (1), comprising: an inner terminal (11) to be connected with a core (2) of the shielded cable (1), an outer terminal (12) to be connected with a shield layer (3) of the shielded cable (1) while at least partly accommodating the inner terminal (12) with a dielectric element (13) provided between the inner and outer terminals (11,12), and a locking member (14) mountable in or on the outer terminal (12) for locking the inner terminal (11) so as not to come out characterized in that the locking member (14) comprises latching means (42; 45) for latching the locking member (14) with the inner and/or outer terminals (11, 12). A shielding terminal according to claim 1, wherein an opening (22) is formed in part of a circumferential surface of the outer terminal (12), the locking member (14) being at least partly mountable in the opening (22). A shielding terminal according to one or more of the preceding claims, wherein a shield plate is mounted on or provided in the locking member (14), the shield plate being preferably connectable with the shield layer (4) and/or the outer terminal (12). A shielding terminal according to one or more of the preceding claims, wherein the locking member (14) is formed with a locking edge (45) being engageable for locking with a rear portion of the inner terminal (11), preferably of a connection portion (15) thereof. A shielding terminal according to claim 4, wherein the latching means (42; 45) comprise hooking portions (42) engageable with at least one crimping portion (23) of the outer terminal (12). A shielding terminal according to one or more of the preceding claims, wherein the locking member (14) comprises a locking means (44; 46; 48) for coming into engagement with a sheath (5) of the shielded cable (1) and/or with the dielectric member (13). A method of mounting a shielding terminal (10) with an end of a shield cable (1), comprising the following steps: connecting an inner terminal (11) with a core (2) of the shielded cable (1), connecting an outer terminal (12) with a shield layer (3) of the shielded cable (1) while at least partly accommodating the inner terminal (12) with a dielectric element (13) provided between the inner and outer terminals (11, 12), and mounting a locking member (14) in or on the outer terminal (12) for locking the inner terminal (11) so as not to come out, characterized in that the method further comprises the step of latching the locking member (14), which comprises latching means (42; 45), with the inner and/or outer terminals (11, 12). A method according to claim 7, wherein the locking member (14) is mounted in an opening (22) formed in part of a circumferential surface of the outer terminal (12). A method according to claim 7 or 8, wherein a shield plate is mounted on or provided in the locking member (14), the shield plate being preferably connected with the shield layer (4) and/or the outer terminal (12).

Inventors: KOIDE TAKASHI, KOIDE, TAKASHI
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 2001
Main classification: H01R9
IPC codes: H01R9, H01R13, H01R24, H01R103