Process for making press-in connection type contact

Abstract: A process for making a press-in connection type contact comprising a first press-in connection terminal, a second press-in connection terminal and a third press-in connection terminal, each extending upwardly, the first terminal and the second terminal located side by side in an extending direction of a conductor, the third terminal located on an intermediate line between the first and second terminals but displaced radially of the conductor, press contacting surfaces formed respectively on opposing corners between the first and third press-in connection terminals and between the second and third press-in connection terminals and extending vertically, the conductor being able to be inserted, under pressure, into a space between the opposing press contacting surfaces of the first and third press-in connection terminals and a space between the opposing press contacting surfaces of the second and third press-in connection terminals for establishing a physical and electric connection between the contact and the conductor, the process for making a press-in connection type contact comprising the steps of splitting the first, second and third press-in connection terminals from one another by shear-cutting a plate member; extruding the third press-in connection terminal in one direction on an intermediate line between the first and second terminals radially of the conductor; forming press contacting surfaces on those corner portions of the first, second and third press-in terminals which are disposed opposite to the opposing corner portions of the first, second and third press-in terminals by swaging; and extruding the third press-in terminals in the other direction on the intermediate line between the first and second press-in terminals radially of the conductor so that the press contacting surfaces are brought to be in opposite relation.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a press-in connection type contact, in which a physical and electric connection (press-in connection) between a contact and a conductor is achieved by causing the contact to pierce through a coating of and catching the conductor. 2. Brief Description of the Prior Art U.S. Pat. No. 4,270,831 discloses a press-in connection type contact comprising a first press-in connection terminal, a second press-in connection terminal and a third press-in connection terminal, each extending upwardly, the first terminal and the second terminal located side by side in an extending direction of a conductor, the third terminal located on an intermediate line between the first and second terminals but displaced radially of the conductor, press contacting surfaces formed respectively on opposing corners between the first and third press-in connection terminals and between the second and third press-in connection terminals and extending vertically, the conductor being able to be inserted, under pressure, into a space between the opposing press contacting surfaces of the first and third press-in connection terminals and a space between the opposing press contacting surfaces of the second and third press-in connection terminals for establishing a physical and electric connection between the contact and the conductor. This contact has such advantages that the width in the implanting pitch direction of the contacts to be implanted in a row in a connector body can be reduced, in other words, the contact width in the parallel pitch direction of a multiconductor cable can be reduced, thus enabling to adequately cope with the multiconductor cable having a very small pitch arrangement, and in addition, its contact area relative to the conductor can be increased and a possible cutting of the conductor can be effectively prevented, thus ensuring a highly reliable electric connection. However, while this conventional press-in connection type contact has the advantages as outlined above, it has the following disadvantages. Since it is essential that after a plate member is shear-cut to form three terminals, the inner corner portion of the third press-in connection terminal located at the center is swaged from the inner side and thereafter the inner corner portions of the opposite first and second press-in connection terminals are swaged respectively from the inner side, thereby to form the above-mentioned respective press contacting surfaces. This procedure takes much time and labor, which results in high cost. Moreover, since the shear-cut surfaces of the three press-in connection terminals are generally on a co-plane, it is difficult to perform the swaging operation smoothly and with high precision, with respect to the inner corner portions facing this plane when the slant swaging operation is to be performed from the inner side, because of dead corners generated to the respective swaging tools. Furthermore, harmful burrs are liable to be formed on the protruding side for the swaging operation. In addition, this procedure for cutting (cornering) each short contact pin to form the press contacting surfaces is not only unsuitable for mass production line but also impractical because it takes much time for such procedure and the cost is increased. SUMMARY OF THE INVENTION The present invention has been accomplished in order to obviate the above disadvantages inherent in the prior art. It is therefore an object of the present invention to provide a process for making a press-in connection type contact, in which beautiful press contacting surfaces can be formed, with high precision and through a very simple manner, on respective inner corner portions of the three terminals. Another object of the present invention is to provide a process for making a press-in connection type contact, which is capable of enhancing the practical use thereof by making the best use of the advantage of the press-in connection type contact of the above-mentioned three terminals structure. To achieve the above objects, there is essentially provided a process for making a press-in connection type contact comprising a first press-in connection terminal, a second press-in connection terminal and a third press-in connection terminal, each extending upwardly, the first terminal and the second terminal located side by side in an extending direction of a conductor which is to be inserted, the third terminal located on an intermediate line between the first and second terminals but displaced radially with respect to the conductor which is to be inserted, press contacting surfaces formed respectively on opposing corners between the first and third press-in connection terminals and between the second and third press-in connection terminals and extending vertically, the conductor being able to be inserted, under pressure, into a space between the opposing press contacting surfaces of the first and third press-in connection terminals and a space between the opposing press contacting surfaces of the second and third press-in connection terminals for establishing a physical and electric connection between the contact and the conductor, the process for making a press-in connection type contact comprising the steps of splitting the first, second and third press-in connection terminals from one another by shear-cutting a plate member; extruding the third press-in connection terminal in one direction on an intermediate line between the first and second terminals radially with respect to the conductor which is to be inserted; forming press contacting surfaces on those corner portions of the first, second and third press-in terminals which are disposed opposite to the opposing corner portions of the first, second and third press-in terminals by swaging; and extruding the third press-in terminal in the other direction on the intermediate line between the first and second press-in terminals radially with respect to the conductor which is to be inserted so that the press contacting surfaces are brought to be in opposite relation. The process of the present invention may further comprise the steps of increasing the distance between the first press-in terminal and the second press-in terminal after the first extruding step and before the swaging step; and decreasing the distance between the first press-in terminal and the second press-in terminal after the extruding step in the other direction. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1(A) through 1(F) are side views showing a plate member and a contact for explaining the steps for carrying out a process for making a press-in connection type contact according to a first embodiment of the present invention; Figs. 2(A) through 2(F) are cross-sectional views of a plate member and a contact for explaining the steps for carrying out a process for making a press-in connection type contact according to a first embodiment of the present invention; Figs. 3(A) through 3(F) are cross-sectional views of a molding tool, a plate member and a contact for explaining the steps for carrying a process for making a press-in connection type contact according to a first embodiment of the present invention; Figs. 4(A) through 4(G) are side views of a plate member and a contact for explaining the steps for carrying out a process for making a process for making a press-in connection type contact according to a second embodiment of the present invention; Figs. 5(A) through 5(G) are cross-sectional views of a plate member and a contact for explaining the steps for carrying out a process for making a press-in connection type contact according a second embodiment of the present invention; Figs. 6(A) through 6(G) are cross-sectional views of a molding tool, a plate member and a contact for explaining the steps for carrying out a process for making a press-in connection type contact according to a second embodiment of the present invention; Fig. 7 is a perspective view of a press-in connection type contact which can be obtained in accordance with the first and second embodiments; Fig. 8 is a side view of Fig. 7; Fig. 9 is a front view of Fig. 7; and Fig. 10 is a sectional view showing the state in which the press-in connection type contact is in press-in connection with a conductor. DETAILED DESCRIPTION OF THE EMBODIMENT Figs. 1, 2 and 3 illustrate a first embodiment of the present invention, and(A) through (F) of these Figures 1, 2 and 3 respectively illustrate the corresponding steps for carrying out a process for making a press-in connection type contact according to the first embodiment. As shown in (A) and (B) of Figs. 1, 2 and 3, an unnecessary portion 2 of the plate member 1 is sheared off so that the plate member 1 may have a width dimension good enough. In (B) of Fig. 3, the reference numeral 3 denotes a shear cutter for shearing off the unnecessary portion 2. As shown in (C) of Figs. 1, 2 and 3, the plate member 1 is subjected to punching-out operation using shear-cutters 7a, 7b and 7c so as to be separated or sheared to first, second and third press-in connection terminals 4, 5 and 6 which are connected together at their basal portions. At the same time, the intermediate third press-in connection terminal 6 is extruded radially of a conductor 8 to be pressed in but on an intermediate line between the opposite first and second press-in connection terminals 4 and 5. The shear cutter for punching out the first, second and third press-in connection terminals 4, 5 and 6 is operated to shear the plate member 1 to form the first, second and third press-in connection terminals 4, 5 and 6 by knocking a sliding cutter 7c into a space between first and second stationary cutters 7a and 7b, and at the same time, extrude the third press-in connection terminal 6 toward one side on the intermediate line between the first and second press-in connection terminals 4 and 5 by the central sliding cutter 7c. Although not illustrated, it may be arranged such that the sliding cutter 7c is disposed as a stationary cutter, and the stationary cutters 7a and 7b are disposed as sliding cutters so that the first and second press-in connection terminals 45 are extruded toward one side radially of the conductor 8 from opposite sides of the third press-in connection terminal 6. In any case, the third press-in connection terminal 6 is extruded in the above-mentioned direction relative to the remaining first and second press-in connection terminals 4 and 5. As shown in (D) of Figs. 1, 2 and 3, the third press-in connection terminal 6 is further extruded in the above-mentioned direction by an extruding mold 9, so that the third press-in connection terminal 6 is separated sufficiently from the first and second press-in connection terminals 4 and 5. The required amount of extrusion of the third press-in connection terminal 6 may be appropriately set when the shear-cutting operation is made as shown in (C) of Figs. 1, 2 and 3, so that the extruding process as shown in (D) of Figs. 1, 2 and 3 can be omitted. As shown in (E) of Figs. 1, 2 and 3, those corner portions of the first, second and third press-in connection terminals 4, 5 and 6 opposite to the opposing corner portions thereof are subjected to swaging operation by using swaging molds 10a and 10b so that press contacting surfaces 4a, 5a and 6a are formed. The swaging mold 10a is of a stationary type, while the other swaging mold 10b is of a sliding type. The stationary swaging mold 10a has a female mold portion 10c for receiving therein the third press-in connection terminal 6. This female mold portion 10c is provided at a bottom surface thereof with a slant mold portion for cornering an outer corner portion of the third press-in connection terminal 6. A male mold portion 10d of the sliding swaging mold 10b is knocked into the female mold portion 10c to forcibly press the third press-in connection terminal 6 against the bottom surface of the female mold portion 10c so that the press contacting surface 6a is formed. At the same time, the second and third press-in connection terminals 5 and 6 are fitted to and supported by opposite shoulder portions at an inlet portion of the female mold portion 10c of the stationary swaging mold 10a, and the outer corner portions of the first and second press-in connection terminals 4 and 5 are swaged by the slant swaging portions which are formed on opposite sides of a basal portion of the male mold portion 10d of the sliding swaging mold 10b to form the press contacting surfaces 4a and 5a. As shown in (F) of Figs. 1, 2 and 3, the third press-in connection terminal 6 is extruded toward the opposite side of the first and second press-in connection terminals 4 and 5 (that is, toward the other side of the first and second press-in connection terminals 4 and 5 radially of the conductor 8 but on the intermediate line between the first and second press-in connection terminals 4 and 5), using the extruding mold 11, thereby to accomplish the objective press-in connection type contact. As shown in Figs. 7 through 10, in the press-in connection type contact thus constructed, the first, second and third press-in connection terminals 4, 5 and 6 are located side by side and extend upwardly from a connecting portion 12, the first and second press-in connection terminals 4 and 5 are located away from each other in an axial direction of the conductor 8 which is to be pressed therein, and the third press-in connection terminal 6 is located on an intermediate line between the first and second press-in connection terminals 4 and 5 but displaced radially of the conductor 8. The press-in connection type contact further has slant press contacting surfaces 4a and 6a formed respectively on opposing corners between the first and third press-in connection terminals 4 and 6 and extending in a vertical direction, and slant press contacting surfaces 5a and 6a formed respectively on opposing corners between the second and third press-in connection terminals 5 and 6 and extending in a vertical direction. A first press-in space 13a is formed between the press contacting surfaces 4a and 6a, while a second press-in space 13b is formed between the press contacting surfaces 5a and 6a. As shown in Fig. 10, the conductor is inserted, under pressure, into the first and second press-in spaces 13a and 13b and press-held between the press contacting surfaces 4a and 6a and between the press contacting surfaces 5a and 6a, for establishing a physical and electric connection between the contact and the conductor. More specifically, the first, second and third press-in connection terminals 4, 5 and 6 are provided with pointed ends 14, respectively, which are formed by the shear-cutting and swaging, or formed thereafter. The conductor 8 is inserted into the first and second press-in spaces 13a and 13b while allowing the coating of the conductor 8 to be pierced through by these pointed ends 14, thereby establishing the physical and electric connection. Figs. 4, 5 and 6 illustrate a second embodiment of the present invention. (A) through (F) of Figs. 4, 5 and 6 show corresponding processes to each other. In this embodiment, the processes shown in (D) and (G) are added to those of the first embodiment, and the remaining processes of this second embodiment is substantially the same to the first embodiment. Specifically, according to this second embodiment, after the first, second and third press-in connection terminals 4, 5 and 6 are formed by shearing, as shown in (D) of the respective Figures, the distance between the first and second press-in connection terminals 4 and 5 are sufficiently increased by using a dilating mold 15, and then the terminals 4, 5 and 6 are subjected to swaging as shown in (E) of the respective Figures. By making the distance between the first and second press-in connection terminals 4 and 5 longer than the final distance, the swaging operation can be performed smoothly, the swaging mold 10b can be more freely designed, and the precision of the press contacting surfaces 4a and 5a formed by swaging can be improved. As shown in (E) of the respective Figures, after the third press-in connection terminal 6 is extruded into a normal position, the distance of the first and second press-in connection terminals 4 and 5 are decreased using a reducing mold 16, so that the distance is corrected to the normal one, as shown in (G) of the respective Figures. As shown in Figs. 7 through 10, there can be obtained a press-in connection type contact having the first, second and third press-in connection terminals 4, 5 and 6 and press contacting surfaces 4a, 5a and 6a at opposite corner portions of the respective terminals as in the first embodiment. According to the present invention, there can be provided the effective press contacting surfaces to the press-in connection type contact having a three terminals structure as shown in the above-mentioned U.S. Pat. No. 4,270,831, and there can be made best use of the advantages of this contact. That is, in the process for swaging the outer corner portions of the first, second and third press-in connection terminals obliquely from the outer side in the state where the third press-in connection terminal is extruded toward one side, the swaging operation can be smoothly performed without being disturbed by the remaining press-in connection terminals, thus enabling to form beautiful press contacting surfaces with high precision. It should be understood that the present invention is not limited to the above embodiments, and various changes and modifications can be made within the scope of the invention as defined in the appended claims.

Claims: A process for making a press-in connection type contact comprising a first press-in connection terminal, a second press-in connection terminal and a third press-in connection terminal, each extending upwardly, said first terminal and said second terminal located side by side in an extending direction of a conductor which is to be inserted, said third terminal located on an intermediate line between said first and second terminals but displaced radially with respect to said conductor, press contacting surfaces formed respectively on opposing corners between said first and third press-in connection terminals and between said second and third press-in connection terminals and extending vertically, the conductor being able to be inserted, under pressure, into a space between said opposing press contacting surfaces of said first and third press-in connection terminals and a space between said opposing press contacting surfaces of said second and third press-in connection terminals for establishing a physical and electric connection between said contact and the conductor, said process for making a press-in connection type contact comprising the steps of: splitting said first, second and third press-in connection terminals from one another by shear-cutting a plate member; extruding said third press-in connection terminal in one direction on an intermediate line between said first and second terminals radially with respect to the conductor which is to be inserted; forming press contacting surfaces on those corner portions of said first, second and third press-in terminals which are disposed opposite to said opposing corner portions of said first, second and third press-in terminals by swaging; and extruding said third press-in terminal in the other direction on the intermediate line between said first and second press-in terminals radially with respect to the conductor which is to be inserted so that said press contacting surfaces are brought to be in opposite relation. A process for making a press-in connection type contact as claimed in claim 1, further comprising the steps of: increasing the distance between said first press-in terminal and said second press-in terminal after said first extruding step and before said swaging step; and decreasing the distance between said first press-in terminal and said second press-in terminal after said extruding step in the other direction.

Inventors: KANEKO TETSUYA, KANEKO, TETSUYA
Applicants: YAMAICHI ELECTRONICS CO LTD, YAMAICHI ELECTRONICS CO., LTD.
Application year: 1993
Main classification: H01R43
IPC codes: H01R43, H01R4