A terminal fitting

Abstract: [Object] To prevent a lateral displacement of a wire resulting from pushing forces from crimping pieces. [Solution] A pair of crimping pieces 17A, 17B extend upward from opposite side edges of a bottom wall 11, and are crimped into connection with a wire placed on the bottom wall 11 W by being wound around the wire W. The pair of crimping pieces 17A, 17B are offset to each other in the longitudinal direction of the wire W. By causing the wire W to engage restricting portions 18A, 18B formed on the bottom wall 11, a lateral displacement of the wire W is restricted against pushing forces acting on the wire W from the crimping pieces 17A, 17B in directions normal to the longitudinal direction of the wire W while the crimping pieces 17A, 17B are being crimped into connection with the wire W.

Description: The present invention relates to a terminal fitting provided with a crimping portion to be crimped or bent or folded into connection with a wire. A known terminal fitting provided with a crimping portion to be crimped into connection with a wire is disclosed in USP No. 5,599,212. In this terminal fitting, the crimping portion is formed by a pair of crimping pieces extending upward from the opposite side edges of a bottom wall and is crimped into connection with a wire supplied onto the bottom wall by winding the crimping pieces around the wire. The pair of crimping pieces are offset to each other in the longitudinal direction of the wire so as to avoid a mutual interference when they are crimped. Thus, a plurality of kinds of wires having different diameters can be handled. However, if the crimping pieces are offset so that one crimping piece is crimped in one position, a fastening force is obliged to be lower as compared to a case where a pair of crimping pieces are crimped together in one position. As a countermeasure to strengthen a fastening force, it may be considered to increase a degree of deformation of the crimping pieces when they are crimped, thereby making the outer diameters of the wire and the crimping pieces smaller when the wire is fastened. However, in the case that the wire is fastened in one position by either one of the left and right crimping pieces, a lateral (direction normal to the longitudinal direction of the wire) pushing force acting on the wire from the crimping piece increases as the degree of deformation for crimping is increased. Thus, the wire is pushed sideways from its proper fastened position. As a result, the resin coating is pushed out between the leading end of the crimping piece and the side edge of the bottom wall opposite from this crimping piece. In a worst case, the pushed-out coating may be cut. From US-A-2302767 a terminal for electrical conductors and more particularly for a insulated multi-strand cord is known, having a U-shaped terminal member at which prongs are bent upwardly at right angles. The function of the prongs is to pierce an insulation on the cord and also an insulation on the individual multiple strands of the conductor and make electrical contact with the strands of the conductor as the terminal member is attached to the cord by means of a die. During the attachment overformed projections of the terminal member are bent towards the cord. The overformed projections also contact the prongs and cause the prongs to more positively engage the strands of the conductor to make a good electrical contact therewith. In view of the above situation, an object of the present invention is to prevent a lateral displacement of a wire resulting from pushing forces acting from crimping pieces. This object is solved according to the invention by a terminal fitting according to claim 1. Preferred embodiments of the invention are subject of the dependent claims. According to the invention, there is provided a terminal fitting in which at least one pair of crimping pieces extending preferably upward from the opposite side edges of a bottom wall are to be bent on, preferably wound substantially around a wire placed on the bottom wall to be crimped or bent or folded into connection with or on the wire, and are offset to each other in the longitudinal direction of the wire, comprising: restricting portions for engaging the wire placed on the bottom wall to displace the wire slightly towards a crimping piece from the transverse center position at its portion in contact with the respective restricting portion and to at least partly restrict, preferably fully restrict a lateral displacement of the wire against pushing forces which act on the wire from the crimping pieces in a direction substantially normal to the longitudinal direction of the wire while the crimping pieces are being crimped. Even if the lateral pushing forces acting on the wire from the crimping pieces are large during crimping, a lateral displacement of the wire can be prevented by the restricting portions. According to the invention, the restricting portions are offset to each other or arranged in zigzag shape by being displaced to sides opposite from the crimping pieces corresponding thereto from a transverse center position. In other words, the restricting portions comprise first and second restricting portions and the crimping pieces corresponding first and second crimping portions, the first restricting portion corresponding to the first crimping portion being displaced from the center along the longitudinal direction of the terminal fitting in a direction away from the corresponding first crimping portion. i.e. towards the side of the second crimping portion, while the second restricting portion is displaced from the center in a direction away from the corresponding second crimping portion, i.e. towards the side of the first crimping portion. Accordingly, the wire will have a zigzag or S-shape in a portion thereof corresponding to the restricting portions, when at least partly inserted into the terminal fitting. Since the restricting portions are in offset arrangement, the wire is fastened while lying in a S-shaped line. Thus, a loose movement of the wire in its longitudinal direction can be restricted even if a pulling force acts on the wire in such a direction. Preferably, the restricting portions are provided in longitudinal positions substantially corresponding to the longitudinal position of the respective crimping pieces. Further preferably, one or more of the restricting portions are provided by embossing the bottom wall and/or side wall(s) of the terminal fitting. Still further preferably, one or more of the restricting portions are provided by cutting the bottom wall and/or side wall(s) of the terminal fitting and bending the cut portion inwardly. Still further preferably, one or more of the restricting portions are provided by embossing corner portions between the bottom wall and side wall(s) of the terminal fitting. Most preferably, at least one restricting portion is formed with a locking surface to restrict a loose movement of the wire in a longitudinal direction thereof. The inventive terminal fitting may preferably take the following specific constructions. (1) The restricting portions may be formed by embossing the bottom wall. (2) The restricting portions may be formed by embossing the side walls extending upward from the side edges of the bottom walls or making cuts in portions of the side walls and bending these cut portions inwardly. (3) The restricting portions may be formed by embossing corner portions between the bottom wall and the side walls extending upward from the side edges of the bottom wall. Most preferably, the terminal fitting further comprises one or more insulation-displacement portions for cutting an insulation coating of a wire to be at least partly inserted into the terminal fitting and connecting to a core thereof. These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments. FIG. 1 is a perspective view of a first embodiment, FIG. 2 is a plan view of the first embodiment, FIG. 3 is a side view of the first embodiment, FIG. 4 is a bottom view of the first embodiment, FIGS. 5(A) and 5(B) are lateral sections showing states before and where a wire is fastened, respectively, FIGS. 6(A) and 6(B) are a partial plan view and a partial perspective view of a second embodiment, respectively, FIGS. 7(A) and 7(B) are a partial plan view and a partial perspective view of a third embodiment, respectively, and FIGS. 8(A) and 8(B) are a partial plan view and a partial perspective view of a fourth embodiment, respectively. Hereinafter, a first embodiment of the present invention is described with reference to FIGS. 1 to 5. An insulation-displacement terminal fitting T according to this embodiment is produced e.g. by applying bending and embossing to a conductive metallic plate material stamped or cut out into a specified shape. The insulation-displacement terminal fitting T is substantially narrow in forward and backward or longitudinal directions as a whole, and a pair of side walls 12 extend at an angle different from 0° or 180°, preferably substantially normal or upward from opposite side edges of a bottom wall 11 over its entire length. An engaging portion 13 for the connection with a mating male terminal fitting (not shown) is formed at a substantially front half of the terminal fitting T, a crimping portion 16 to be crimped or folded or bent into connection with or onto a wire W is formed at the rear end of the terminal fitting T, and insulation-displacement portions 15 to be connected with the wire W by insulation displacement are formed before or adjacent the crimping portion 16. The engaging portion 13 is comprised of the bottom wall 11, the side walls 12 and ceiling walls 14 which extend inwardly from the upper edges of the side walls 12 while being at least partly placed substantially one over the other, and is in the form of a substantially rectangular tube extending in forward and backward or longitudinal directions as a whole. The insulation-displacement portions 15 are formed in substantially V-shape by embossing the side walls 12 to project inwardly, and preferably two pairs of the insulation-displacement portions 15 are provided one after the other. The wire W is pushed in between the insulation-displacement portions 15 in a direction at an angle different from 0° or 180°, preferably substantially normal to the longitudinal direction thereof while having its longitudinal axis preferably oriented in forward and backward directions (direction substantially parallel to the longitudinal direction of the terminal fitting T). As the wire W is at least partly pushed in, bent projecting ends 15A of the insulation-displacement portions 15 cut an insulation or resin coating Wa of the wire W open and bite in the cut-open sections to be brought into contact with a core Wb, with the result that the wire W is or can be connected with the insulation-displacement portions 15 by insulation displacement. It should be noted that this step of insulation displacement is performed simultaneously with or before or after a crimping step to be described later. Next, the crimping portion 16 is described. The crimping portion 16 is comprised of the flat bottom wall 11, lowered rear end portions 12R of the pair of side walls 12 extending at an angle different from 0° or 180°, preferably substantially normal or upward from the opposite side edges of the bottom wall 11, and a first and a second crimping pieces 17A, 17B extending further upward from the upper edges of the rear end portions 12R of the respective side walls 12. The first crimping piece 17A is provided at the front end of the rear end portion 12R of the right (upper side in FIG. 2) side wall 12 of the terminal fitting T, whereas the second crimping piece 17B is provided at the rear end of the rear end portion 12R of the left (lower side in FIG. 2) side wall 12. In other words, the first and second crimping pieces 17A, 17B provided at the right and left sides, respectively, are offset to each other in the longitudinal direction of the wire W (in forward and backward directions), i.e. are in so-called offset arrangement. The pair of crimping pieces 17A, 17B as above are crimped as follows. The wire W is supplied between the crimping pieces 17A and 17B in a direction substantially normal to its longitudinal direction to be placed on the bottom wall 11 while having its longitudinal axis substantially oriented in forward and backward directions. Subsequently, as shown in FIG. 5(B), the crimping pieces 17A, 17B are wound or bent or folded substantially around the outer surface of the wire W while being deformed and arcuately curved inwardly. In this way, the crimping portion 16 is crimped into connection with the wire W. In the crimping step, the respective crimping pieces 17A, 17B are preferably individually crimped into connection with the wire W in two positions since the two crimping pieces 17A, 17B are in offset arrangement. However, in the case that the wire W is fastened in one position by either the right or left crimping pieces 17A or 17B, a lateral (direction normal to the longitudinal direction of the wire W; leftward direction from the first crimping piece 17A located at the right side and rightward direction from the second crimping piece 17B located at the left side) pushing force acts on the wire W from the crimping piece 17A or 17B. If there are clearances between the inner surface of the side walls 12 and the wire W, the wire W may be laterally displaced by the pushing force from the crimping piece 17A or 17B. If the wire W should be laterally displaced, the resin coating Wa of the wire W may be pushed out between the leading end of the crimping piece 17A or 17B and the upper edge of the side wall 12 at the side of the bottom wall 11 opposite from the crimping piece 17A or 17B. In a worst case, the pushed-out resin coating Wa may be cut. Accordingly, in this embodiment, a first and a second restricting portions 18A, 18B are provided on the bottom wall 11 as a means for restricting a lateral displacement of the wire W. The restricting portions 18A, 18B are preferably formed to project like a substantially triangular pyramid from the upper surface (on which the wire W is placed) of the bottom wall 11 by applying embossing to the bottom wall 11. With respect to forward and backward directions (longitudinal direction of the fastened wire W by crimping), the first restricting portion 18A is located at the substantially same longitudinal position as the first crimping piece 17A and the second restricting portion 18B is located at the substantially same longitudinal position as the second crimping piece 17B. Specifically, the first restricting portion 18A corresponding to the first crimping piece 17A at the right side is deviated to the left (away from the first crimping piece 17A) from a transverse center position, whereas the second restricting portion 18B corresponding to the second crimping piece 17B at the left side is deviated to the right (away from the second crimping piece 17B) from the transverse center position. Thus, the wire W placed on the bottom wall 11 is displaced slightly to the right (toward the first crimping piece 17A) from the transverse center position at its portion in contact with the first restricting portion 18A while being displaced slightly to the left (toward the second crimping piece 17B) from the transverse center position at its portion in contact with the second restricting portion 18B. As a result, a section of the wire W located at and near the restricting portions 18A, 18B lies in a slightly S-shaped line as shown in FIG. 2 in its fastened state by crimping. Each restricting portion 18A, 18B has three ridges: one ridge 19R extends in forward and backward or longitudinal directions, and the other two ridges 19F extend to the left and right or transverse direction from the front end of the ridge 19R. A front surface of each restricting portion 18A, 18B defined by the ridges 19F and the bottom wall 11 acts as a locking surface 19S preferably extending substantially normal to the forward and backward directions (longitudinal direction of the wire W). Next, the action of this embodiment is described. Even if the lateral (direction normal to the longitudinal direction of the wire W) pushing forces act on the wire W from the crimping pieces 17A, 17B while the crimping portion 16 is being crimped, the wire W is received by the restricting portion 18A, 18B at the side opposite from the crimping piece 17A, 17B giving the pushing force. Thus, the wire W is held substantially in its initially placed position against the lateral pushing force substantially without being laterally displaced. Further, the first restricting portion 18A located at the front side with respect to the longitudinal direction of the wire W is displaced to the left from the transverse center position, the second restricting portion 18B located at the rear side with respect to the longitudinal direction of the wire W is displaced to the right from the transverse center position, and the two restricting portions 18a, 18B are in offset arrangement along the lateral and/or longitudinal direction. Accordingly, the wire W is fastened by crimping while its longitudinal axis lies in a substantially S-shaped line. Therefore, even if a pulling force acts in the longitudinal direction of the wire W, a loose movement of the wire W in its longitudinal direction is restricted by the engagement with the two restricting portions 18A, 18B. Particularly, since the restricting portions 18A, 18B are substantially in the form of a triangular pyramid and the front surfaces thereof act as the locking surfaces 19S extending substantially normal to the longitudinal direction of the wire W, the resin coating Wa of the wire W is hooked by the locking surfaces 19S while a top portion 19 T of the restricting portions 18A, 18B bite in it when a backward pulling force acts. Thus, a loose movement of the wire W can be highly effectively restricted against the pulling force. Next, a second embodiment of the present invention is described with reference to FIG. 6. The second embodiment differs from the first embodiment in the construction of the restricting portions. Since the other construction is similar or same as in the first embodiment, no description is given on the structure, action and effects thereof by identifying it by the same reference numerals. Restricting portions 21A, 21B of the second embodiment are formed by embossing bottom end portions (portions near the bottom wall 11) of the side walls 12 to project inwardly. It should be noted that the positional relationship between the first and second crimping pieces 17A and 17B and the one between the first and second crimping pieces 21A and 21B with respect to forward and backward directions and transverse direction are the same as in the first embodiment. Next, a third embodiment of the present invention is described with reference to FIG. 7. The third embodiment differs from the first embodiment in the construction of the restricting portions. Since the other construction is similar or same as in the first embodiment, no description is given on the structure, action and effects thereof by identifying it by the same reference numerals. Restricting portions 22A, 22B of the third embodiment are formed by embossing corner portions between the bottom wall 11 and the side walls 12 standing from the side edges of the bottom walls 11 to project inwardly. It should be noted that the positional relationship between the first and second crimping pieces 17A and 17B and the one between the first and second crimping pieces 22A and 22B with respect to forward and backward directions and transverse direction are the same as in the first embodiment. Next, a fourth embodiment of the present invention is described with reference to FIG. 8. The fourth embodiment differs from the first embodiment in the construction of the restricting portions. Since the other construction is similar or same as in the first embodiment, no description is given on the structure, action and effects thereof by identifying it by the same reference numerals. Restricting portions 23A, 23B of the fourth embodiment are formed by making cuts in portions of the side walls 12 standing from the side edges of the bottom wall 11 and bending cut portions inwardly. The restricting portions 23A, 23B are substantially rectangular when viewed from the front (in the substantially same direction as the longitudinal direction of the wire W) and extend in a direction at an angle different from 0° or 180°, preferably substantially normal to the side walls 12 and the bottom wall 11. It should be noted that the positional relationship between the first and second crimping pieces 17A and 17B and the one between the first and second crimping pieces 23A and 23B with respect to forward and backward directions and transverse direction are the same as in the first embodiment. The present invention is not limited to the above described and illustrated embodiment. For example, the 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 of the present invention as defined in the claims. (1) Although the present invention is applied to the terminal fitting provided with an insulation displacement portion and a crimping portion in the foregoing embodiment, it is also applicable to terminal fittings not provided with an insulation displacement portion and a crimping portion. (2) Although the restricting portion is provided in positions displaced to the right or left from the transverse center position in the foregoing embodiment, it may be provided in the transverse center position according to the present invention. (3) Although the restricting portions are formed by embossing the bottom wall in the foregoing embodiment, they may be formed by making cuts in portions of the bottom wall and bending cut portions inwardly according to the present invention. (4) Although the invention has been described with reference to embodiments in which there are provided restricting portions of the same type, it is to be understood that two different types of restricting portions according to the first to fourth embodiment may be used in the same terminal fitting. LIST OF REFERENCE NUMERALS T terminal fitting 11 bottom wall 12 side wall 17A first crimping piece 17B second crimping piece 18A first restricting portion 18B second restricting portion 19S locking surface 21A, 22A, 23A first restricting portion 21B, 22B, 23B second restricting portion

Claims: A terminal fitting (T) in which at least one pair of crimping pieces (17) extending preferably upward from the opposite side edges of a bottom wall (11) are to be bent on, preferably wound substantially around a wire (W) to be placed on the bottom wall (11) to be crimped into connection with the wire (W), and are offset to each other in the longitudinal direction of the terminal fitting (T), characterized by : restricting portions (18; 21; 22; 23) for engaging the wire (W) placed on or close to the bottom wall (11) whereby the restricting portions (18; 21; 22; 23) are offset to each other by being displaced to sides opposite from the crimping pieces (17) corresponding thereto from a transverse center position to displace the wire (W) slightly towards a crimping piece (17) from the transverse center position at its portion in contact with the respective restricting portion (18; 21; 22; 23) and to at least partly restrict a lateral displacement of the wire (W) against pushing forces which act on the wire (W) from the crimping pieces (17) in a direction substantially normal to the longitudinal direction of the wire (W) while the crimping pieces (17) are being crimped. A terminal fitting according to claim 1, wherein the restricting portions (18; 21; 22; 23) are provided in longitudinal positions substantially corresponding to the longitudinal position of the respective crimping pieces (17). A terminal fitting according to one or more of the preceding claims, wherein one or more of the restricting portions (18; 21) are provided by embossing the bottom wall (11) and/or side wall(s) (12) of the terminal fitting (T). A terminal fitting according to one or more of the preceding claims, wherein one or more of the restricting portions (23) are provided by cutting the bottom wall (11) and/or side wall(s) (12) of the terminal fitting (T) and bending the cut portion inwardly. A terminal fitting according to one or more of the preceding claims, wherein one or more of the restricting portions (22) are provided by embossing corner portions between the bottom wall (11) and side wall(s) (12) of the terminal fitting T). A terminal fitting according to one or more of the preceding claims, wherein at least one restricting portion (18; 21; 22; 23) is formed with a locking surface (19S) to restrict a loose movement of the wire (W) in a longitudinal direction thereof. A terminal fitting according to one or more of the preceding claims, further comprising one or more insulation-displacement portions (15) for cutting an insulation coating (Wa) of a wire (W) to be at least partly inserted into the terminal fitting (T) and connecting to a core (Wb) thereof.

Inventors: AOYAMA MASAHIKO, KOJIMA EIJI, AOYAMA, MASAHIKO, KOJIMA, EIJI
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 2001
Main classification: H01R4
IPC codes: H01R4