Terminal hardware for flat-type conductor and a method of making a terminal conductor

Terminal hardware for a flat-type conductor is provided which can provide a high contact pressure between the terminal hardware and the conductor and a superior holding power against a tension tending to separate the terminal hardware from the conductor. At a terminal end of the flat-type conductor, the conductor is exposed on an upper surface. A base plate is formed to extend from a rear end of the terminal hardware, and a top plate is provided so as to face the base plate and be capable of being opened and closed. A pair of crimping portions are provided at opposite side edges of a rear end of the base plate. Further, both the base plate and the top plate have undulating portions, respectively. The terminal end of the flat-type conductor is inserted between the base plate and the top plate. The pair of crimping portions pierces the insulation sheet of the flat-type conductor from one side toward the other. Then, the terminal end of the flat-type conductor is sandwiched between the base plate and the top plate from both of the upper and lower surfaces, and is compressed. At the same time, the pair of the crimping portions is crimped. Accordingly, a portion of the flat-type conductor where the conductor is provided is bent and sandwiched between the base plate and the top plate contacts the conductor.

BACKGROUND OF THE INVENTION
 1. Field of Invention
 The present invention relates to a terminal hardware used to connect to a
 terminal of a flat-type conductor, and to a method of making the terminal
 hardware.
 2. Description of Related Art
 A flexible flat cable (FFC) and a flexible printed circuit (FPC) are known
 as flat-type conductors. For example, a construction of an FFC is
 described as follows. Plural strips of conductors are aligned in parallel
 and covered and pressed by insulating sheets from both upper and lower
 sides. Thus, the FFC is formed to have a flexible ribbon-shape. There are
 two methods to connect terminal hardware to each of the conductors of the
 FFC as described above: a method that connects the terminal hardware to
 the conductor covered by the insulating sheet, and a method that connects
 the terminal hardware to the conductor exposed on one side by peeling the
 insulating sheet of the terminal.
 The latter method is disclosed in Japanese Utility Model Laid-Open
 Publication No. Sho. 63-73862, for example. As shown in FIG. 16, at the
 terminal of FFC 1, a predetermined amount of an insulating sheet 2 on the
 upper side is peeled, and a conductor 3 is exposed on the upper side.
 Terminal hardware 4 having a base plate 6 extending from a rear side of a
 connection portion 5 is provided to be connected to another terminal
 hardware. Further, a top plate 7 is integrally formed with the base plate
 6 so as to face the base plate 6 and to be capable of being opened and
 closed with respect to the base plate 6. Claws 8 are provided at opposite
 side edges of the open end of the top plate 7.
 A portion of the exposed conductor 3 is inserted between the base plate 6
 and the top plate 7. The claws 8 pierce the FFC 1 and are crimped on the
 lower side to opposite side edges of the base plate 6. Thus, the FFC 1 is
 sandwiched between the base plate 6 and the top plate 7, and the top plate
 7 is pressed against the conductor 3 to establish connection.
 However, in the above-described method, since the entire surface of the
 flat-shaped top plate 7 contacts the conductor 3, the contact pressure
 becomes low. Thus, the reliability of electrical contact is poor.
 Further, when a tension is applied in a longitudinal direction of the FFC
 1, there is a possibility that the claws 8 separate from the FFC 1
 (insulating sheet 2) and the terminal hardware becomes separated from the
 FFC 1, since the claws 8 are caught by the FFC 1 only at a portion where
 the claws pierce the FFC.
 When a terminal hardware is connected to the conductor 3, which is exposed
 at a surface, there is a way to avoid the claws 8 piercing the FFC. In
 this case, the terminal of FFC is formed to have a comb-shape so that each
 portion where the conductor 3 is exposed is left as a tooth portion. The
 claws 8 hold the tooth portions of the comb-shape and are crimped thereto
 to fix the terminal hardware to the terminal of the FFC. However, the
 terminal hardware 4 is more easily separated from the terminal
 particularly in this case.
 The present invention is provided to eliminate the above-described
 drawbacks. An objective of the present invention is to provide a terminal
 hardware for a flat-type conductor having a high contact pressure between
 a conductor and the terminal hardware, and a superior holding force
 against a tension to separate the terminal hardware from the terminal.
 SUMMARY OF THE INVENTION
 To achieve the above and/or other goals, the present invention provides a
 terminal hardware connected to a terminal end of a flat-type conductor
 having a conductor exposed on one surface. The terminal hardware includes
 a pair of plates that face each other and receive the conductor
 therebetween, and a crimping portion that projects from a side edge of one
 of the pair of the plates and that is bendable and crimpable to a side
 edge of the other one of the pair of the plates. The pair of plates
 respectively has first and second undulating portions. The first and
 second undulating portions undulate in a longitudinal direction of the
 pair of the plates and are configured to be in contact with each other.
 Preferably, the crimping portion is a pair of crimping portions.
 According to the features of the present invention, since the exposed
 surface of the conductor contacts one of the pair of the plates while the
 conductor is bent in an undulating-shape, high contact pressure can be
 achieved. In addition, since the terminal hardware of the present
 invention having undulating plates can provide a wider contact area than
 the terminal hardware with flat plates having the same total length, a
 stable electrical connection can be achieved. Further, since the pair of
 the plates bend the conductor in an undulating-shape and contacts
 therewith, an area of the conductor with a total width can be used to hook
 the terminal conductor. Accordingly, the holding power against a tension
 to separate the terminal hardware from the terminal can be increased.
 In another aspect of the present invention, the first and second undulating
 portions are configured to fit against each other without a gap when the
 flat-type conductor is not inserted therebetween. In this case, when the
 flat-type conductor is inserted between the pair of the plates, the first
 and the second wave portions do not fit against each other. Thus, the
 flat-type conductor has portions having different amounts of compression
 between the pair of the plates. In particular, at a portion where an
 amount of compression is great, the contact pressure between the conductor
 and the plate facing the exposed surface of the conductor becomes high.
 Accordingly, the reliability of electrical contact can be improved.
 Further, the holding power against a tension to separate the terminal
 hardware from the terminal can be further increased.
 In another aspect of the present invention, the terminal hardware further
 includes a cut-in projection provided on one of the pair of plates that
 faces the exposed surface of the conductor. The cut-in projection
 forcefully presses against and bites into the conductor. According to this
 feature of the invention, the contact pressure and holding power against a
 tension to separate the terminal hardware from the terminal can further be
 improved.
 The cut-in projection can be formed by cutting an edge of a triangle in one
 of the pair of the plates and by embossing the triangle in a wedged-shape.
 The cut edge is perpendicular to the longitudinal direction of the pair of
 the plates and is located forwardly in a direction to which the terminal
 hardware is separated from the terminal of the flat-type conductor.
 According to another feature of the present invention, the surface
 projecting in a wedged-shape of the cut-in projection is perpendicular to
 a direction of a tension tending to separate the terminal hardware from
 the terminal and forcefully presses against and bites into the conductor.
 Thus, the holding power against the tension tending to cause separation
 can be further increased.
 In another aspect of the present invention, the pair of plates is formed
 unitarily and in one piece so as to be able to be opened and closed. Thus,
 the number of components can be reduced and it becomes easy to handle the
 terminal hardware.
 Preferably, the first and second undulating portions include a ridge and
 two troughs provided at opposite sides of the ridge in the longitudinal
 direction of the pair of the plates.
 Alternatively, the first and second undulating portions can include two
 troughs spaced in the longitudinal direction of the pair of plates.
 Further, a first cut-in projection can be provided between two troughs,
 and a second cut-in projection is provided at a rear end of the pair of
 plates. Furthermore, a first pair of crimping portions can be provided on
 opposite side edges between the two troughs, and a second pair of crimping
 portions can be provided on opposite side edges at a rear end of the pair
 of plates.
 Preferably, the cut-in projection is located at substantially the same
 position in the longitudinal direction of the pair of plates as a position
 of the crimping portion.
 In another aspect of the present invention, a method for making a terminal
 hardware is provided. The method includes punching out a blank from a
 metal plate. The metal plate has a base plate portion, a tab portion
 extending from one end of the base plate portion, a top plate portion
 parallel to the base plate portion and a folding portion which projects
 from side edge of a connection point of the base plate portion and the tab
 portion and connecting the base plate portion and the top plate portion,
 and a crimping portion projected from a side edge of one of the base plate
 portion or the top plate portion. The method further includes folding the
 folding portion so that the top plate portion faces the base plate portion
 and can be opened and closed at an end of the top plate portion, forming
 the base plate portion and the top plate portion with undulations, and
 bending the crimping portion to project toward the other of the base plate
 portion and the top plate portion.
 Further, the method can include forming a cut in the top plate on a line
 perpendicular to the longitudinal direction of the top plate portion, and
 embossing a triangle portion of the top plate portion to configure a
 wedge-shaped portion extending toward the bottom plate portion. The
 triangle portion includes the cut as one side and an apex directed toward
 an end of the top plate portion in a longitudinal direction of the top
 plate portion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
 In the following, embodiments of the present invention are described with
 reference to figures.
 A first embodiment of the present invention is explained with reference to
 FIGS. 1 through 5.
 In FIG. 1, a flexible flat cable (FFC) 10 is shown as an example of a
 flat-type conductor. Plural strips of conductors 11 are aligned in
 parallel and spaced at predetermined distances. The plural strips of
 conductors 11 are covered and pressed by insulating sheets 12 from both
 upper and lower sides. Thus, the FFC is formed to have a flexible
 ribbon-shape. Predetermined areas of the insulating sheet on an upper side
 are peeled off at a terminal end of the FFC 10. Thus, conductors 11 are
 aligned while the upper surfaces are exposed. The insulating sheet may be
 peeled off on both the upper and lower sides.
 The terminal hardware 20 of the present embodiment is a male terminal
 hardware and is made of a metal plate having superior conductivity by
 press molding, for example. The terminal hardware 20 includes a tab 21,
 which is configured to be engaged with a female terminal hardware, and a
 base plate 22 extending from the rear end of the tab 21. The terminal
 hardware 20 further includes a top plate 23 facing the base plate 22. A
 blank for forming the terminal hardware 20 is shown in FIG. 2. The blank
 has the tab 21 and the base plate 22 formed as a single strip. The top
 plate 23 is provided parallel to the base plate 22 via a folding portion
 24, which projects from a side edge at a proximal end of the tab 21 (i.e.
 the connection point between the tab 21 and the base plate 22). The pair
 of crimping portions 26 project from opposite side edges of the base plate
 22. The blank may be formed, for example, by punching from the metal
 plate. When the folding portion 24 is tightly folded twice as shown in
 FIG. 1, the top plate 23 faces the base plate 22 and can be opened and
 closed at the rear end (right side in FIG. 1). Then, the base plate 22 and
 the top plate 23 are formed with complementary undulations, for example,
 by pressing. Finally, the crimping portions are bent toward the top plate
 22 to extend upwardly from the base plate.
 A portion of the top plate 23 faces the base plate 22 so as to be able to
 be opened and closed and is about the same length as the length of the
 conductor 11 exposed. Further, the widths of the base plate 22 and the top
 plate 23 are set slightly wider than the width of the conductor 11. The
 pair of crimping portions 26 project upwardly from opposite side edges at
 the rear end of the base plate 22. The tip of each crimping portion is
 formed to be sharp.
 Further, the base plate 22 and top plate 23 have undulating portions 30.
 Each undulating portion includes a large ridge 31 approximately at the
 center in the longitudinal direction and small troughs 32 at the base of
 both sides of the ridge 31. The undulating portions of the base plate 22
 and top plate 23 are formed so as to tightly engage with each other almost
 without a gap when the terminal of the FFC 10 is sandwiched therebetween.
 In the following, a connection process of the first embodiment is
 explained.
 As shown in FIGS. 1 through 3, the top plate 23 of the terminal hardware is
 opened upwardly. Under this condition, the FFC 10 is inserted between the
 base plate 22 and the top plate 23, while the terminal hardware 20 is
 aligned with the conductor 11. Next, the pair of the crimping portions 26
 formed on the base plate 22 pierces the insulating sheet 12 upwardly.
 Then, the terminal on the FFC 10 is sandwiched between the base plate 22
 and the top plate 23 and is pressed therebetween. Then, the pair of the
 crimping portions 26 is bent inwardly and is crimped to opposite side
 edges of the top plate 23 at the rear end. Accordingly, as shown in FIGS.
 4 and 5, the base plate 22 and the top plate 23 hold the conductor 11
 therebetween and are closed together to be connected with each other.
 According to the first embodiment, since the conductor 11 is sandwiched
 between the base plate 22 and the top plate 23, both of which have
 undulating portions 30, the conductor 11 is also bent in the same
 undulating-shape. In other words, since the bent top plate 23 contacts the
 conductor 11 so as to be engaged with the conductor 11, high contact
 pressure can be achieved and consequently a stable electrical connection
 can be achieved.
 Further, the FFC 10 as described above is used in such a way that the
 terminal hardware 20 connected to the terminal is stored in a cavity of a
 connector housing (not shown). A tension toward the rear end (direction of
 the arrow in FIG. 4) may be applied to the FFC 10. However, according to
 the present embodiment, since the top plate 23 and the base plate 22 bend
 the FFC 10 in an undulating-shape and engage with the FFC 10, a firm
 engagement can be provided. Thus, the holding power against the tension to
 separate increases. Accordingly, the terminal hardware 20 is prevented
 from easily separating from the terminal of the FFC 10.
 FIGS. 6 through 8 show a second embodiment of the present invention. The
 second embodiment can be called a modification of the first embodiment.
 Therefore, in the following explanation, the different portions have been
 mainly explained. The same numerals as in the first embodiment are given
 to portions having the same functions as that of the first embodiment, and
 a repetition of the explanation thereof is omitted.
 In the terminal hardware 20A of the second embodiment, the base plate 22A
 and the top plate 23A facing the base plate 22A respectively have
 undulating portions 30A in the same manner as the first embodiment.
 However, as shown by the broken line in FIG. 6, the terminal hardware 20A
 is formed so that the undulating portions 30A fit to each other without a
 gap, when the base plate 22A and the top plate 23A contact each other
 without inserting the terminal of the FFC 10 therebetween.
 In the second embodiment, as in the first embodiment, as shown in FIG. 6,
 the terminal of FFC 10 is inserted between the top plate 23A and the base
 plate 22A, while the top plate 23A is opened upwardly. Then, as shown in
 FIG. 7, the top plate 23A and the base plate 22A are closed and press the
 terminal of FFC 10. As described above, the undulating portions 30A of the
 base plate 22A and the top plate 23A are formed in a shape to fit to each
 other when the FFC 10 is not inserted therebetween. Thus, when the
 terminal of the FFC 10 is inserted between the base plate 22A and the top
 plate 23A, the FFC 10 is deformed and compressed. In more detail, as shown
 in FIG. 8, where the original thickness of the conductor 11 is as shown by
 the broken line, an amount of compression of the conductor 11 is
 relatively small at the vicinity of the ridge 31 and trough 32 of the
 undulating portion 30A, while an amount of compression is larger at the
 other wide areas. Accordingly, as a whole, a high contact pressure can be
 achieved between the top plate 23A and the conductor 11 at the wide areas,
 and thus, reliability of the electric connectivity can be improved.
 Next, the third embodiment of the present invention is explained with
 reference to FIGS. 9 through 14. In the following, portions that are
 different from the first embodiment are mainly explained. The same
 numerals as in the first embodiment are given to portions having the same
 functions as those of the first embodiment, and a repetition of the same
 explanation is omitted.
 In the terminal hardware 20B of the third embodiment, the base plate 22B
 and the top plate 23B respectively have undulating portions 40, each of
 which includes two troughs 41 spaced in a longitudinal direction. Two
 pairs of crimping portions project upwardly from opposite side edges of
 the flat portion 42 at the rear end and from opposite side edges of the
 flat portion 42 between the two troughs of the base plate 22B,
 respectively.
 The top plate 23B includes two cut-in projections 44 respectively provided
 on the flat portions 42 at the front and rear side of the rear side trough
 41. In more detail, as shown in FIG. 10, each cut-in projection 44 forms a
 triangle having an apex directed rearwardly in the plane of the flat
 portion 42. One side 45 in FIG. 10 of the triangle, which is perpendicular
 to the longitudinal direction of the top plate 23, is cut off, and the
 flat portion 42 of the triangle is embossed to have a wedged-shape
 extending toward the bottom side. As shown in FIG. 11, which is a
 perspective view from the bottom side, a cut end 46, which is shaped as a
 downward triangle, projects in a direction perpendicular to the
 longitudinal direction of the top plate 23B.
 When the terminal hardware 20B of the third embodiment is connected to the
 terminal of FFC 10, as shown in FIGS. 9 and 12, while the top plate 23B is
 opened with respect to the base plate 22B, the terminal of FFC 10 is
 inserted between the base plate 22B and the top plate 23B. Then, the two
 pairs of the crimping portions 26 projecting from the base plate 22B
 pierce the insulating sheet 12 upwardly so that the terminal of the FFC 10
 is sandwiched between and pressed by the base plate 22B and the top plate
 23B. At the same time, as shown in FIGS. 13 and 14, the two pairs of the
 crimping portions 26 are respectively bent inwardly and are crimped to
 opposite side edges of the flat portions 42 of the top plate 23 to
 complete the connection.
 Thus, according to the third embodiment, as well as in the first and the
 second embodiments, the conductor 11 contacts the top plate 23B while the
 conductor 11 is bent. In particular, a high contact pressure can be
 achieved at the vicinity of the troughs 41 of the top plate 23B.
 Further, when the FFC 10 is sandwiched between the top plate 23B and the
 base plate 22B, the cut-in projections 44 forcefully press against and
 bite into the conductor 11. Accordingly, a hook can be provided against a
 direction of a tension tending to separate the terminal hardware from the
 terminal. In addition, the cut end 46, which is perpendicular to the
 longitudinal direction of the top plate 23B, is provided in the front side
 of the cut-in projection 44. The cut end 46 forcefully presses against and
 bites into the conductor 11. Accordingly, the holding power of the FFC 10
 against the tension further increases.
 Further, since the above-described cut-in projections 44 can provide high
 contact pressure between the top plate 23B and the conductor 11, it is
 efficient to improve reliability of the electrical connectivity.
 FIG. 15 shows a fourth embodiment of the present invention. In the fourth
 embodiment, the shape of the terminal end of the FFC 10A is changed. Here,
 the terminal end of the FFC 10A is formed in a comb-shape by leaving only
 portions of insulation where the conductors 11 are provided.
 When the terminal hardware 20 of the first embodiment is connected to the
 FFC 10A, the crimping portions 26 provided on the base plate 22 hold the
 comb-tooth portion 14 and are crimped to the opposite side edges of the
 top plate 23 to be fixed with each other. In this case, since the crimping
 portion 26 is not required to pierce the insulating sheet 12, the
 connecting operation of the terminal hardware becomes easier. Further, a
 possibility to damage the FFC 10A can be reduced.
 Since the comb-tooth portion 14 is bent in an undulating-shape, and the
 undulating-shaped portion engages with the base plate 22 and the top plate
 23, the holding power against the tension tending to separate the terminal
 hardware from the terminal can be increased.
 The terminal hardware 20B of the third embodiment can also be connected to
 the FFC 10A. Since the two pairs of crimping portions 26 simply hold the
 comb-tooth portion 14, the crimping portions 26 cannot provide a holding
 power against the tensile direction. However, in addition to the
 comb-tooth portion 14 being bent in an undulating-shape to be engaged with
 the top plate 23B and the base plate 22B, the cut-in projections 44
 forcefully press against and bite into the conductor 11. Accordingly, the
 holding power against a tension tending to separate the terminal hardware
 from the terminal can be achieved sufficiently.
 It is noted that the present invention is not limited by the embodiments
 explained above using the description and drawings, but the following
 embodiments, for example, can also be included in the scope of the present
 invention. Further, in addition to the following, the present invention
 can be embodied with a variety of changes in so far as it does not depart
 from the subject of the present invention.
 (1) The embodiments described above have a top plate unitarily provided
 with the base plate, and have an advantage that the handling of the
 terminal hardware is convenient and easier. However, it is possible to
 provide the top plate separately from the base plate.
 (2) The terminal hardware can be connected with the terminal so that the
 top plate and the base plate are reversed. In this case, the base plate
 contacts the conductor.
 (3) The crimping portions can be provided on the top plate instead of the
 base plate. Further, the crimping portion can be provided only at one side
 edge of the top or bottom plate, instead of a pair of them provided on
 opposite side edges.
 (4) In the embodiments described above, the widths of the base plate and
 the top plate are wider than the width of the conductor. However, the
 widths of the base plate and the top plate can be narrower than the
 conductor so that the crimping portions pierce the conductor.
 (5) In the embodiments described above, the tips of the crimping portions
 have sharp points to pierce the FFC easily. However, when the crimping
 portion holds the comb-tooth portion as shown in the fourth embodiment,
 the sharp points are not required.
 (6) a female-type terminal hardware can be provided according to the
 present invention as well as the male-type terminal hardware.
 (7) The terminal hardware of the present invention can be used with
 flat-type conductor, such as an FPC (flexible printed circuit), which has
 a conductor covered by insulating layers, formed in a flat-shape and
 exposed at a terminal end, as well as the FFC explained in the embodiment
 described above, as an example.
 It is noted that the foregoing examples have been provided merely for the
 purpose of explanation and are in no way to be construed as limiting of
 the present invention. While the present invention has been described with
 reference to certain embodiments, it is understood that the words which
 have been used herein are words of description and illustration, rather
 than words of limitation. Changes may be made, within the purview of the
 appended claims, as presently stated and as amended, without departing
 from the scope and spirit of the present invention in its aspects.
 Although the present invention has been described herein with reference to
 particular means, materials and embodiments, the present invention is not
 intended to be limited to the particulars disclosed herein; rather, the
 present invention extends to all functionally equivalent structures,
 methods and uses, such as are within the scope of the appended claims.
 The present disclosure relates to subject matter contained in priority
 Japanese Application No. HEI 11-301326, filed on Oct. 22, 1999, which is
 herein expressly incorporated by reference in its entirety.