Abstract:
A terminal fitting includes an open-barrel shaped electric wire crimping section for connecting a conductor of an electric wire to the terminal fitting by crimping. The electric wire crimping section has a clamping region in a range except for both ends of the electric wire crimping section in a wiring direction of the conductor. A fixing portion is formed by displacing a part of the clamping region of the electric wire crimping section to the conductor. Locking portions are disposed at both sides of the fixing portion in the wiring direction of the conductor with the fixing portion being located between them respectively. The locking portions are configured for coupling the fixing portion and a remainder of the electric wire crimping section to each other in a step-like way.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a terminal fitting. 
     2. Description of the Related Art 
     In Japanese Patent Application Laid-Open No. 2005-222815, a terminal fitting having an electric wire crimping section for connecting an electric wire to the terminal fitting by crimping is disclosed. In this terminal fitting, the construction in which the groove is formed on the contact surface of the electric wire crimping section which contacts the conductor of the electric wire is adopted. In this construction, the periphery of the conductor is caught by the groove. Thereby the conductor-fixing force of the electric wire crimping section is enhanced. 
     In Japanese Patent Application Laid-Open No. 2008-262842, there is disclosed a terminal fitting having the electric wire crimping section constructed of the substrate part where an electric wire is placed and a pair of barrel pieces projected from both sides of the substrate part and crimped from the outside to the core exposed to the outside at the end of the electric wire. In this construction, by crimping both barrel pieces to the core, the terminal fitting is electrically connected to the electric wire. 
     In the terminal fitting described in Japanese Patent Application Laid-Open No. 2005-222815, the depth of the groove is limited to the range of the sheet thickness of the electric wire crimping section. Thus the groove has a small locking area in locking the conductor thereto. Therefore when the electric wire crimping section is thin, there is a case in which a sufficient conductor-fixing force cannot be obtained. 
     In the terminal fitting described in Japanese Patent Application Laid-Open No. 2008-262842, by forming the concave portion which decreases the sheet thickness of the barrel pieces on the inner surfaces thereof and disposing the core along the inner surface of the concave portion, it is possible to enhance the core-retaining force of both barrel pieces and improve the reliability in the connection between the terminal fitting and the electric wire. But in this case, when the crimping force of both barrel pieces is set high, the barrel pieces spread with a crimping operation. Therefore there is a great reduction in the sheet thickness of portions of the barrel pieces disposed at a position corresponding to the position of the concave portion. Thereby there occurs a problem that the strength of the electric wire crimping section becomes short. 
     The present invention has been completed based on the above-described situation. It is an object of the present invention to improve the conductor-fixing force of an electric wire crimping section. It is another object of the present invention to secure the strength of the electric wire crimping section. 
     SUMMARY OF THE INVENTION 
     To achieve the above-described or other objects, the invention provides a terminal fitting comprising an open-barrel shaped electric wire crimping section for connecting a conductor of an electric wire to the terminal fitting by crimping, the electric wire crimping section having a clamping region in a range except for both ends of the electric wire crimping section in a wiring direction of the conductor; a fixing portion formed by displacing a part of the clamping region of the electric wire crimping section to the conductor; and a plurality of locking portions disposed at both sides of the fixing portion in the wiring direction of the conductor with the fixing portion being located therebetween respectively and having a form of coupling the fixing portion and a remainder of the electric wire crimping section to each other in a step-like way. 
     According to the above-described construction, in a state in which the conductor is crimped to the electric wire crimping section, the conductor is caught by the locking portion. Thereby the electric wire crimping section has an improved conductor-fixing force. In addition, because the thickness of the electric wire crimping section is not decreased, the strength thereof can be securely obtained. 
     Each locking portion has a thickness in a direction in which the electric wire crimping section is displaced to the conductor, and the thickness may be set larger than that of the fixing portion. According to the above-described construction, even though a large clamping force is set in crimping the wire barrel part to the conductor, the thick locking portion little deforms. Thus there is no decrease in the locking area of the locking portion in locking the conductor thereto. 
     The fixing portion may have an end surface disposed nearly along the wiring direction of the conductor. Thereby the conductor is disposed along the end surface of the fixing portion. 
     A cut-into portion projected to the conductor like a rib may be formed on the end surface of the fixing portion. Thereby the fixing portion locks the conductor thereto owing to the operation of the cut-into portion which cuts into the periphery of the conductor. Thus the fixing portion has a high fixing force. 
     The electric wire crimping section may have a substrate part on which the conductor is plated; and a pair of barrel pieces, projected from both sides of the substrate part, which are crimped to the conductor from an outside. The fixing portion is formed on the barrel pieces. A concave portion concave to an inner surface of each of the barrel pieces is formed at a portion, of an outer surface of each of the barrel pieces thereof, which corresponds to the fixing portion; and a convex portion projected to the conductor is formed at a position, of an inner surface of each of the barrel pieces, which corresponds to the fixing portion with the convex portion and the concave portion being disposed back to back. Because the convex portion projected to the conductor is formed on the inner surface of each of the barrel pieces, it is possible to enhance the conductor-holding force of each barrel piece and improve the connection reliability between the terminal fitting and the electric wire. Further the concave portion is formed on the outer surface of each of the barrel pieces, and the convex portion is formed on the inner surface of each barrel piece with the convex portion and the concave portion being disposed back to back. Therefore compared with a case in which only the concave portion which decreases the sheet thickness of both barrel pieces is formed thereon, the strength of both barrel pieces is properly secured. This operation and effect are similar to those of the first embodiment of the invention described above. 
     The convex portion and the concave portion may be formed on only the barrel pieces. The convex portion and the concave portion are formed efficiently on the barrel pieces which apply a high crimping force to the conductor. Therefore it is possible to prevent the construction from becoming complicated more than necessary. 
     The convex portion and the concave portion may be formed in the shape of a striate extending in a direction intersecting with a direction in which the conductor is wired. This construction further enhances the core-retaining force of the barrel piece. 
     The present invention also provides a method of producing a method of producing a terminal fitting having a substrate part supporting an electric wire; and a pair of barrel pieces projected from both sides of the substrate part. A conductor exposed to an outside at an end of the electric wire is placed on the substrate part. Both barrel pieces are crimped to the conductor placed on the substrate part. Outer surfaces of the barrel pieces are stricken as soon as a crimping operation is performed or after the crimping operation finishes to form a concave portion concave toward an inner-surface of each of the barrel pieces on the outer surface of each barrel piece and a convex portion projected to the conductor at a position, of the inner surface of each of the barrel pieces, where the convex portion and the concave portion are disposed back to back. Because the convex portion and the concave portion are formed as soon as the caulking crimping operation is performed or after the crimping operation finishes, both barrel pieces crimped to the conductor is effectively prevented from undergoing deformation of opening outward owing to spring back. 
     According to the present invention, it is possible to improve the conductor-fixing force of the electric wire crimping section. It is also possible to secure the strength of the electric wire crimping section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view showing a state in which an electric wire is crimped to a terminal fitting of an embodiment 1 of the present invention. 
         FIG. 2  is a plan view showing a state in which the electric wire is crimped to the terminal fitting. 
         FIG. 3  is a plan view showing the configuration of an electric wire crimping section of a metal plate. 
         FIG. 4  is a sectional view taken along a line X-X of  FIG. 3 . 
         FIG. 5  is a plan view showing the configuration of an electric wire crimping section of a metal plate in an embodiment 2. 
         FIG. 6  is a sectional view taken along a line Y-Y of  FIG. 5 . 
         FIG. 7  is main parts-broken away side view showing a terminal fitting of an embodiment 3. 
         FIG. 8  is a main parts-depicted plan view showing the terminal fitting. 
         FIG. 9  is a main parts-depicted plan view showing a terminal fitting of an embodiment 4. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment 1 
     The embodiment 1 of the present invention is described below with reference to  FIGS. 1 through 4 . A terminal fitting  10  of the embodiment 1 is of a female type formed by bending a metal plate  10 P punched in a predetermined configuration. A front part of the terminal fitting  10  is formed as a prism-shaped terminal fitting connection section  11 . The terminal fitting connection section  11  has a known form functioning as a connection means to be connected to a long and narrow tab (not shown in the drawings) of a male mating terminal fitting. 
     A rear part of the terminal fitting  10  is formed as an open barrel-shaped electric wire crimping section  12 . A front end of an electric wire  30  is connected to the electric wire crimping section  12  by crimping. The electric wire  30  is constructed of a conductor  31  serving as a core consisting of a twisted wire formed by twisting a plurality of thin metal wires together and an insulating coating  32  surrounding the conductor  31 . At the front end of the electric wire  30 , to connect the electric wire  30  to the terminal fitting  10 , the insulating coating  32  is removed in advance to expose the front end of the conductor  31  to the outside. As materials of the conductor  31 , copper, a material (for example, aluminum) having a higher rigidity than the copper, and a material (for example, aluminum) having a lower conductivity than the copper are used. In the embodiment 1, the conductor  31  made of aluminum or an aluminum alloy is used. 
     A front part of the electric wire crimping section  12  is formed as a wire barrel part  13  to which the conductor  31  is connected. A rear part of the electric wire crimping section  12  is formed as an insulation barrel part  14  to which a portion, of the front end of the electric wire  30 , where the insulating coating  32  surrounding the conductor  31  is not removed is connected. The wire barrel part  13  has a form in which a pair of symmetrical barrel pieces  16  is extended from left and right side edges of a bottom plate portion  15 . The electric wire  30  crimped to the wire barrel part  13  is pressurized with the electric wire  30  being entirely surrounded with the bottom plate portion  15  and a pair of the barrel pieces  16  and electrically conductively fixed to the wire barrel part  13  by a fixing force generated by the pressurization. 
     In a crimped state, the projected front end of the conductor  31  is positioned forward from the front edge of the barrel pieces  16 . In the longitudinal direction of a wire barrel (barrel piece  16 ), the range of a clamping region  17  to be clamped by a crimper of an applicator (not shown in the drawings) is limited to a range except the front and rear ends of the barrel piece  16 . The front and rear edges of the clamping region  17  are formed as an oblique (tapered) bellmouth  18  such that the front and rear edges of the clamping region  17  are slightly diametrically larger than the clamping region  17 . Because the bellmouth  18  is formed by limiting the range of the clamping region  17  to the above-described range, the front and rear edges of the inner periphery of the barrel piece  16  do not cut the thin metal wires composing the conductor  31 . 
     A fixing portion  20  and a locking portion  21  are formed on the wire barrel part  13 . The fixing portion  20  has a wall-like form formed by displacing a portion, of the wire barrel part  13 , which is disposed within the range of the clamping region  17  in the longitudinal direction of the wire barrel part  13  to the conductor  31  (to inner peripheral surface) and has a flat end surface along the direction in which the conductor  31  is wired. The conductor  31  is disposed along the end surface of the fixing portion  20 . In a state of the flat metal plate  10 P before it is bent, the fixing portion  20  is parallel with a region (hereinafter referred to as non-fixing portion  22 ) of the wire barrel part  13  other than the fixing portion  20 . A region in which the fixing portion  20  is formed in a left-to-right direction (circumferential direction in crimped state) covers a range from a position inward (side of bottom plate portion  15 ) from a rising edge of one of the barrel pieces  16  to a position inward (side of bottom plate portion  15 ) from a rising edge of the other of the barrel pieces  16 , including the bottom plate portion  15 . The fixing portion  20  is rectangular. A thickness dimension Ta of the fixing portion  20  is uniform in the entire region thereof and equal to a thickness dimension Tb of the non-fixing portion  22 . 
     The locking portion  21  has a form in which front and rear edges of the fixing portion  20  and the non-fixing portion  22  are coupled to each other in a step-like way and left and right edges of the fixing portion  20  and the non-fixing portion  22  are coupled to each other in a step-like way. In other words, the locking portion  21  forms a continuous rectangular frame over the entire periphery of the fixing portion  20 . In a direction in which the fixing portion  20  is displaced, namely, inward and outward directions, a thickness dimension Tc of the locking portion  21  is larger than the thickness dimension Ta of the fixing portion  20  and the thickness dimension Tb of the non-fixing portion  22 . Although the thickness dimension Tc of the locking portion  21  is smaller than twice the thickness dimension Ta of the fixing portion  20 , the thickness dimension Tc thereof may be larger than twice the thickness dimension Ta of the fixing portion  20 . An inner surface (surface of locking portion  21  opposed to conductor  31 ) of the locking portion  21  is continuous with an inner surface (surface of fixing portion  20  which contacts conductor  31 ) of the fixing portion  20  with an inner surface of the locking portion  21  flush with that of the fixing portion  20 . An outer surface of the locking portion  21  is continuous with an outer surface of the non-fixing portion  22  with the outer surface of the locking portion  21  flush with that of the non-fixing portion  22 . In the longitudinal direction of the locking portion  21 , the locking portion  21  is positioned within the range of the clamping region  17 . 
     In a state in which the conductor  31  is crimped to the wire barrel part  13 , the inner surface of the fixing portion  20  and that of the locking portion  21  closely contact the peripheral surface of the conductor  31 , whereas a rectangular frame-shaped region, of the inner surface of the non-fixing portion  22 , which is disposed in the vicinity of the locking portion  21  does not contact the conductor  31 . In the crimped state, an edge-like corner disposed on the inner surface of the locking portion  21  cuts into the periphery of the conductor  31 . Owing to the cut-into operation, a large locking area is secured between the conductor  31  and the wire barrel part  13  in a radial direction of the terminal fitting  10 . Thereby a fixing force is enhanced between the wire barrel part  13  and the conductor  31  in the longitudinal direction of the terminal fitting  10 . 
     Even though a large clamping force is set in crimping the wire barrel part  13  to the conductor  31 , the thick locking portion  21  is difficult to have collapse deformation. Thus there is no decrease in the locking area of the locking portion  21  in relation to the conductor  31 . Even though the fixing portion  20  has deformation of curving outward in relation to the locking portion  21  owing to a reaction force applied to the fixing portion  20  from the conductor  31 , the thick locking portion  21  little deforms. Therefore there is no fear that the locking area of the conductor  31  in relation to the locking portion  21  decreases. Further because it is unnecessary to form a concave portion which decreases the thickness of the electric wire crimping section  12  on the inner surface thereof, the strength of the entire electric wire crimping section  12  is ensured. 
     Embodiment 2 
     The embodiment 2 of the present invention is described below with reference to  FIGS. 5 and 6 . The construction of a fixing portion  43  formed on a wire barrel part  42  of an electric wire crimping section  41  of a terminal fitting  40  of the embodiment 2 is different from the fixing portion  20  of the terminal fitting  10  of the embodiment 1. Because other constructions of the embodiment 2 are the same as those of the embodiment 1, the same parts of the embodiment 2 as those of the embodiment 1 are denoted by the same reference numerals as those of the embodiment 1, and the description of the constructions, operation, and effect of the embodiment 2 is omitted herein. 
     A fixing portion  43  and a locking portion  44  both similar to those of the embodiment 1 are formed on the wire barrel part  42  of the embodiment 2. A cut-into portion  45  projected to the conductor  31  is formed on an end surface of the fixing portion  43 . The cut-into portion  45  is formed by press work of striking the fixing portion  43  from its outer surface. The cut-into portion  45  extends in a circumferential direction (direction parallel with rising direction of barrel piece  16  from bottom plate portion  15 ) intersecting with the axis of the conductor  31 . A plurality of the cut-into portions  45  is arranged in parallel at certain intervals in the longitudinal direction of the terminal fitting  40 . Each of the cut-into portions  45  is approximately triangular in section. In a state in which the conductor  31  of the electric wire  30  is crimped to the wire barrel part  42 , the cut-into portion  45  cuts into the periphery of the conductor  31 . Thereby the fixing portion provides a high fixing performance. 
     In the embodiments 1 and 2, aspects described below are included in the technical scope of the present invention. 
     (1) In the embodiments 1 and 2, the region in which the fixing portion is formed is disposed within the range inward from the outer edge of the electric wire crimping section. But according to the present invention, the region in which the fixing portion is formed may reach the outer edge of the electric wire crimping section. 
     (2) In the embodiments 1 and 2, one fixing portion is formed on the electric wire crimping section. But according to the present invention, a plurality of the fixing portions may be formed on the electric wire crimping section. 
     (3) In the embodiments 1 and 2, description has been made on an example in which the terminal fitting is used as a female terminal fitting. But the terminal fitting of the present invention can be also used as a male terminal fitting. 
     Embodiment 3 
     The embodiment 3 of the present invention is described below with reference to  FIGS. 7 and 8 . A terminal fitting  110  of the embodiment 3 is connected to the end of an electric wire  190  and accommodated inside a connector housing not shown in the drawings. In that state, the terminal fitting  110  is fitted on a mating connector not shown in the drawings. Thereby the terminal fitting  110  is conductively connected with a mating terminal fitting not shown in the drawings. The terminal fitting  110  is integrally formed by punching a conductive metal plate consisting of copper or a copper alloy into a predetermined configuration and thereafter bending it and has a band plate-shaped substrate part  111  extended longitudinally over the entire length of the terminal fitting  110 . 
     A connection part  112 , bent in the shape of a prism, which receives the mating terminal fitting and is electrically connected thereto is provided at a front end of the substrate part  111 . A pair of outwardly projected open barrel-shaped holding pieces  113  which is to be crimped to a coating  191  disposed at the end of the electric wire  190  from the outside is provided at both side edges (both edges in widthwise direction orthogonal to extended direction) of a rear end of the substrate part  111 . After both holding pieces  113  are crimped to the coating  191 , both holding pieces  113  are turned along the peripheral surface of the coating  191  of the electric wire  190  and thereafter the front ends thereof are butted to each other at approximately the central portion of the substrate part  111  in the widthwise direction thereof, as shown in  FIG. 8 . Between the connection part  112  and both holding pieces  113  in the longitudinal direction of the terminal fitting  110 , there is provided at both side edges of the substrate part  111  a pair of outwardly projected open barrel-shaped barrel pieces  114  which is to be crimped from the outside to a conductor  192  consisting of a core exposed to the outside at the end of the electric wire  190 . Both barrel pieces  114  are crimped to the conductor  192  of the electric wire  190  in such a way that the barrel pieces  114  cut deep into approximately the central portion of the conductor  192  in the widthwise direction thereof. After the barrel pieces  114  are crimped to the conductor  192 , the front ends of the barrel pieces  114  are butted to each other at approximately the central portion of the substrate part  111  in the widthwise direction thereof. The electric wire crimping section of the present invention is constructed of the substrate part  111  and the barrel pieces  114 . 
     The electric wire  190  is wired in the lengthwise direction (longitudinal direction) of the substrate part  111  and constructed of the conductor  192  formed by twisting wires consisting of aluminum or an aluminum alloy together and the coating  191 , made of an insulating resin, which covers the conductor  192 . 
     A fixing portion  119  is formed on both barrel pieces  114  by displacing a part of both barrel pieces  114  to the conductor  192 . As shown in  FIG. 7 , a pair of the fixing portions  119  is disposed on the barrel pieces  114  at the middle thereof in the longitudinal direction thereof by longitudinally spacing the fixing portions  119  at a certain interval and extends linearly widthwise. A concave portion  115  concave to an inner surface of each barrel piece  114  is formed at a position, of an outer surface thereof, corresponding to the position of each fixing portion  119 . Each concave portion  115  is a striate extending widthwise and V-shaped in section. As shown in  FIG. 8 , the concave portions  115  are straight and disposed in parallel with each other with each concave portion  115  stretching over both barrel pieces  114 . A convex portion  116  projected to the conductor  192  is formed at a position, of the inner surface of each of the barrel pieces  114 , corresponding to the position of each fixing portion  119  with the convex portion  116  and the concave portion  115  disposed back to back. Each convex portion  116  extends linearly widthwise and V-shaped in section. The convex portions  116  are straight in parallel with each other with each convex portion  116  stretching over both barrel pieces  114 . Briefly the convex portion  116  has a configuration matching that of the concave portion  115 . Therefore including portions corresponding to the convex portion  116  and the concave portion  115 , each of the barrel pieces  114  has almost the same thickness over the entirety thereof. The convex portion  116  and the concave portion  115  are formed on only both barrel pieces  114  and not formed on the connection part  112 , the substrate part  111 , and both holding pieces  113 . The fixing portion  119  and portions of each of the barrel pieces  114  disposed forward and rearward therefrom are coupled to each other with a locking portion  118  in a step-like way. 
     The method of producing the terminal fitting  110  of the embodiment 3 and the operation and effect thereof are described below. 
     After the coating  191  disposed at the end of the electric wire  190  is peeled to expose the conductor  192  to the outside, the electric wire  190  is placed on the upper surface of the substrate part  111 . Thereafter both barrel pieces  114  and both holding pieces  113  are crimped to the conductor  192  and the coating  191  respectively by using unshown jigs such as an anvil and a crimper. As a result, both barrel pieces  114  incline inward, and the front ends thereof cut into the central portion of the conductor  192  in the widthwise direction thereof from the outer side (upper side). Thereby the terminal fitting  110  and the electric wire  190  are electrically connected to each other. Convexities, formed at positions of the inner surface of the jig, corresponding to both barrel pieces  114  press the outer surfaces of both barrel pieces  114  with a movement of the jig. As a result, the concave portion  115  is formed on the outer surfaces of both barrel pieces  114  and the convex portion  116  is formed on the inner surfaces thereof and eventually the fixing portion  119  and the locking portion  118  are formed. Thereafter the convex portion  116  of the locking portion  118  cuts into the surface of the conductor  192  like an edge. Thereby the conductor  192  is tightly crimped to the barrel pieces  114 . In this case, even though an oxide film consisting of aluminum oxide is formed on the surface of the conductor  192 , the convex portion  116  destroys the oxide film mechanically as soon as the convex portion  116  is formed by molding. Thus good connection reliability between both barrel pieces  114  and the conductor  192  is securely obtained. 
     In the above-described case, because a force is applied to both barrel pieces  114  in the thickness direction thereof owing to the caulking operation, both barrel pieces  114  are spread, there is a possibility that the strength of a portion, of each of the barrel pieces  114 , corresponding to the concave portion  115  decreases. But according to the embodiment 3, the concave portion  115  and the convex portion  116  are formed on both barrel pieces  114  at back to back positions. Thus compared with a case in which only the concave portion  115  which decreases the sheet thickness of both barrel pieces  114  is formed thereon, the sheet thickness of both barrel pieces  114  does not greatly decrease, and in addition the convex portion  116  keeps an elongation amount of both barrel pieces  114  low. Consequently the strength of both barrel pieces  114  is properly secured. 
     Because the convex portions  116  and the concave portions  115  are formed on only both barrel pieces  114 , i.e., the convex portions  116  and the concave portions  115  are formed efficiently at portions which apply a high crimping force to the conductor  192 . Therefore it is possible to avoid the terminal fitting  110  from having a complicated construction more than necessary. 
     Further because the convex portion  116  and the concave portion  115  are formed in the shape of the striate extending in the direction intersecting with the direction in which the conductor  192  is wired, the conductor-retaining force of the barrel piece is further enhanced. 
     Further because the convex portion  116  and the concave portion  115  are formed as soon as the crimping operation is performed, both barrel pieces  114  crimped to the conductor  192  is effectively prevented from undergoing deformation of opening outward owing to spring back. 
     Embodiment 4 
       FIG. 9  shows the terminal fitting  110  of the embodiment 4. The disposition of the fixing portion  119  and that of the locking portion  118 , namely, the disposition of the convex portion  116  and that of the concave portion  115  are different from those of the embodiment 3. That is, the concave portion  115  has first concave portions  115 A arranged in parallel with each other on one of the outer surfaces of both barrel pieces  114  and second concave portions  115 B arranged in parallel with each other on the other of the outer surfaces of both barrel pieces  114 . The first concave portions  115 A and the second concave portions  115 B are extended linearly in the widthwise direction of both barrel pieces  114  and disposed in a zigzag pattern such that the first concave portions  115 A and the second concave portions  115 B are alternately formed on the outer surfaces of both barrel pieces  114  in the longitudinal direction thereof. The unshown convex portion  116  has also first convex portions and second convex portions at positions back to back in relation to the positions of the first concave portions  115 A and the second concave portions  115 B. 
     In the embodiments 3 and 4, aspects described below are included in the technical scope of the present invention. 
     (1) The convex portion and the concave portion may be formed on the inner and outer surfaces of both barrel pieces by striking the outer surfaces of both barrel pieces after both barrel pieces are crimped to the conductor. 
     (2) The configuration of the convex portion and that of the concave portion are arbitrarily selected. For example, they may be rectangular U-shaped in section. 
     (3) The number of the convex portions and that of the concave portions are arbitrarily selected and may be singular or not less than three. 
     (4) The terminal fitting may be a male terminal fitting having a male tab projected forward. 
     (5) The electric wire may be a copper electric wire having a conductor formed by twisting a plurality of wires consisting of copper or a copper alloy together.