Insulation-piercing connector

Abstract: An insulation-piercing connector includes a connector main body made of an insulating support block having inclined bases inclined in the same direction and a reverse direction and contacts embedded therein to expose contact tails. The contact tails are arranged in first, second, third and fourth rows in parallel with and spaced from each other and staggered or shifted from each other. A cover includes inclined bases inclined in reverse directions to those of the mating inclined bases of the connector main body and receiving slots for receiving the contact tails of the connector main body. Inclined surfaces of the inclined bases of the connector main body and the cover are curved surfaces. The first and second rows and the third and fourth rows of the contact tails are arranged in symmetry with respect to tops of the curved surfaces, respectively. The inclined bases of the connector main body and the cover are provided with protrusions for guiding the connection wires.

Description: This invention relates to an electrical connector whose contacts are connected to connection wires in an insulation-piercing system, and more particularly to an arrangement of contacts and configuration of connection wire receiving portions of a connector main body and urging portions of a cover. There have been many ways for connecting wires and contacts of a connector, such as soldering, wrapping, crimping and insulation-piercing method and the like. In the insulation-piercing method among these ways, a connection wire 3 is forced by means of a cover B into the tail 2 of a contact fixed to an insulating support block 1 of a connector main body A. The tail 2 has a piercing groove 2a at its center and oblique blades 2b on both sides thereof as shown in Fig. 1a. As a result, the coating 3a of a connection wire 3 is cut by the oblique blades 2b to the core 3b of the connection wire 3. Thereafter, the connection wire 3 is forced into the piercing groove 2a so that the contact tail 2 is connected to the core 3b of the connection wire 3. With development of electronics, electronic parts have been required to be highly dense and miniaturized year by year. According to these requirements, an insulation-piercing connector has been proposed in Japanese Patent Application No. 63-253,419 and in EP-A-323 340 as shown in Fig. 2a and 2b. Fig. 2a illustrates a connector main body A in a perspective view, while Fig. 2b illustrates in a perspective view a cover B of the connector turned upside down in order to clearly show its characteristic parts. Referring to Figs. 2a and 3a, the connector main body A includes a plurality of insulation-piercing contact tails (referred to hereinafter as "contact tails") 2 arranged in first, second, third and fourth rows 2A₁, 2A₂, 2B₁ and 2B₂ in parallel and spaced from each other. Moreover, connection wire support inclined bases 3C and 3D for supporting connection wires are arranged on the upper surface of the insulating support block 1 so that the inclined bases 3C and 3D are within the width of the contact tails, and surfaces of the inclined bases 3C and 3D are inclined in reverse directions. Between two inclined bases 3C inclined in the same direction is arranged one inclined base 3D inclined in the reverse direction which is positioned at the center of a contact tail forming the first row 2A₁. Moreover, the contact tails forming the second row 2A₂ are so fixed to the insulating support block 1 that centers of these contact tails are positioned at centers between the contact tails forming the first row 2A₁, and within the width of each of the contact tails are arranged two inclined bases 3D inclined in the same direction and one inclined base 3C inclined in the reverse direction. Further, the contact tails forming the third and fourth rows 2B₁ and 2B₂ are fixed to the insulating support block 1 so as to be shifted by one inclined base 3C and extend over two inclined bases 3D so that the contacts of the third and fourth rows are staggered or alternately shifted. Heights and inclinations of the inclined bases are so selected that only piercing grooves of the contact tails 2 to be connected with the connection wires 3 project upwardly beyond the inclined bases, whereas other contact tails 2 do not project beyond the inclined bases. Referring to Fig. 2b, the cover B includes inclined bases 3E and 3F for supporting connection wires, which are adapted to be inserted between the inclined bases 3C and 3D of the connector main body A and inclined in direction reverse to the inclined directions of the inclined bases 3C and 3D. The cover B further includes receiving slots 5 for receiving the contact tails 2 projecting from the connector main body A. Reference numerals 4A and 4B denote hooks and anchoring members for locking the connector main body A and the cover B. With this arrangement, connection wires, for example, connection wires 3A and 3B of a flat cable 3 (Fig. 3b) are arranged on the surfaces of the inclined bases 3C and 3D, and the cover B is arranged over the connector main body A and forced toward the main body A. As a result, the flat cable 3 is connected to the contacts 2 forming the contact tail rows 2A₁, 2A₂, 2B₁ and 2B₂ as shown in Figs. 1b and 3a. However, the above insulation-piercing connector of the prior art involves the following problems to be solved. Figs. 4a, 4b and 4c illustrate a relationship in height between the contact rows 2A₁, 2A₂, 2B₁ and 2B₂ of the contact tails 2 of the prior art connector shown in Figs. 2a and 2b. (1) As shown in Fig. 4a illustrating the assembled contact main body A and cover B, piercing depths are different as indicated by a and b between the contact rows 2A₁ and 2B₂ arranged on the outer side and the contact rows 2A₂ and 2B₁ on the inner side. Therefore, there is a difference in piercing force by which the core 3b of the connection wire is forced into the piercing groove 2a. Consequently, when a connector is miniaturized, the contacts on the inner side become short resulting in less reliability in connection. (2) When the flat cable 3 shown in Fig. 3b is arranged on the inclined bases 3C and 3D of the connector main body, and the cover B is then arranged thereon and forced toward the connector main body A. As a result, the connection wires 3A are pushed upwardly and connection wires 3B are pushed downwardly so that the contact tails pierce into the connection wires 3A and 3B. In the prior art, a torn length c of the flat cable 3 shown in Fig. 4c is long. Therefore, this connector does not fulfill the requirement of miniaturization. It is an object of the invention to provide an improved insulation-piercing connector which eliminates the disadvantages of the prior art and which improves the reliability in connection and fulfills the requirement of miniaturization. The above object can be accomplished by the measures according to the invention as defined in claim 1. The connector of the invention comprises in particular: (1) Connection wire connecting portions of inclined bases 3C, 3D, 3E and 3F of a connector main body A and a cover B are curved. The connection wire connecting portions are positioned at locations where cores 3b of the connection wires 3 are connected to contact tails. (2) Rows 2A₁ and 2A₂ of the contact tails are arranged at equal distances 1 from tops of the curved portions. Likewise, rows 2B₁ and 2B₂ of the contact tails are arranged at equal distances 1 from tops of the curved portions. (3) Protrusions for guiding the connection wires are provided at out going ends of the inclined bases of the connector main body and the cover. For example, as shown in Fig. 5b, the rows 2A₁ and 2A₂ of the contact tails 2 are arranged in symmetry with respect to the tops of the curved portions C of the inclined bases of the connector main body, while the rows 2B₁ and 2B₂ are arranged in symmetry with respect to the tops of the curved portions D of the inclined bases of the connector main body. Moreover, as shown in Fig. 5a, the cover B is provided with the curved portions E and F which are compatible with the curved portions C and D of the connector main body A when the cover B is arranged on the connector main body A. With the above arrangement according to the invention, the following significant effects can be brought about. (1) Heights of the contact tails 2 forming the rows 2A₁ and 2A₂ and the rows 2B₁ and 2B₂ can be substantially equal. Moreover, piercing distances of cores of the connection wires 3 can be substantially equal as shown by d in Fig. 5c. (2) As shown in Fig. 5c, the protrusions C', D', E' and F' for guiding the connection wires 3 prevent the out going portions of the connection wires from being pushed too far upwardly and downwardly when the cover B is forced toward the connector main body A after the connection wires are arranged between the connector main body A and the cover B. Therefore, torn lengths of the flat cable 3 at its out going portions can be shortened as shown by e in Fig. 5c in comparison with those in the prior art. The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings. Figs. 1a and 1b are explanatory views for the insulation-piercing method of connecting wires to contacts of a connector of the prior art; Figs. 2a and 2b; 3a and 3b; and 4a, 4b and 4c are views for explaining insulation-piercing connections of the prior art; and Figs. 5a, 5b and 5c; and 6a and 6b are views for explaining the insulation-piercing connector according to the invention. Figs. 6a and 6b illustrate in perspective views a connector main body A and a cover B of one embodiment of the invention, respectively. Referring to Fig. 6a, the connector main body A includes an insulating support block 1 having hooks 4A for locking with the cover B. The support block 1 includes connection wire support inclined bases 3C and connection wire support inclined bases 3D inclined in reverse directions to the inclined bases 3C. The support block 1 further includes insulation-piercing contact tails 2 having an equal height and an equal width. As above described, contact tails in rows 2A₁ and 2A₂, and 2B₁ and 2B₂ are arranged in a manner so that they are staggered or alternately shifted. Moreover, the contact tail rows 2B₁ and 2B₂ are shifted relative to the contact tail rows 2A₁ and 2A₂ by the width of one inclined base. Furthermore, the contact tails and the inclined bases are arranged in the following manner. Two inclined bases 3C inclined in the same direction and one inclined base 3D inclined in the reverse direction are arranged within the width of each of the contact tails forming the contact rows 2A₁ and 2A₂. The one inclined base 3D is at a center between the two inclined bases 3C. Two inclined bases 3D and one inclined base 3C are arranged within the width of each of the contacts tail forming the contact tail rows 2B₁ and 2B₂. Moreover, inclinations and heights of the inclined bases are so determined that only piercing grooves 2a of the contact tails to be connected with connection wires project beyond the inclined bases upwardly, whereas other contact tails do not project beyond the inclined bases. This construction is substantially the same as those of the prior art. According to the invention curved portions C and D are provided on the inclined bases 3C and 3D for supporting connection wires on the side of the connector main body A. As can be seen from Figs. 5a-5c, the curved portions are provided at locations corresponding to the cable core connected positions. Moreover, the first and second rows 2A₁ and 2A₂ are located in symmetry with respect to the tops of the curved portions C, while the third and fourth rows 2B₁ and 2B₂ are located in symmetry with respect to the tops of the curved portions D. As shown in Fig. 6, the curved portions of the inclined bases are preferably circular arcuate surfaces. Connection wire guide protrusions C' and D' for guiding connection wires are provided at out going ends of the inclined bases 3C and 3D at least the inclined bases 3C. These protrusions are preferably wormed as extensions of surfaces of the curved portions provided on the inclined bases because a flat cable can be readily deformed without difficulty. Referring to Fig. 6b, the cover B includes anchoring members 4B for locking with the connector main body A, and connection wire support inclined bases 3E and 3F for supporting the connection wires, which are inclined in directions reverse to those of the inclined bases 3C and 3D of the connector main body A. The cover B further includes receiving slots 5 for receiving the contact tails 2, and connection wire guide protrusions E' and F' having curved surfaces for guiding the connection wires (protrusions F' are not shown in the drawing). A flat cable 3 having a plurality of connection wires arranged in a plane is then arranged on the connector main body A, and the cover B is arranged over the connector main body A and forced toward the connector main body A. When the anchoring members 4B of the cover B are locked by the hooks 4A of the connector main body A, the projecting contact tails penetrate into the receiving slots 5 so that the connection wires 3A and 3B of the flat cable 3 are forced into the piercing apertures 2a of the contact tails 2 to be connected with the contacts. At the same time, the connection wires 3A are embraced and securely held to be prevented from removing from connector by means of the inclined bases 3C and 3E and 3D and 3E of the connector main body A and the cover B. Moreover, the connection wire guide protrusions C' and D' and E' and F' serve to guide the connection wires 3A and 3B so that torn lengths of the flat cable are shortened. Instead of providing on extensions of the curved portions, the connection wire guide protrusions of the connector main body A and the cover B may be provided on flat portions of out going ends as shown in dash lines in Fig. 5. If the out going lines of the connection wires are only one side, the connection wire guide protrusions may be provided only on this side. As can be seen from the above explanation, the connector concerning the present invention includes contacts arranged in four rows staggered and adapted to be connected with connection wires in insulation-piercing method by the use of inclined bases for supporting the connection wires. By making equal respective heights and respective piercing depths of the contact tails, the connector according to the invention is high in reliability in connection to wires and accomplishes miniaturization of connector owing to shortened torn lengths of a flat cable.

Claims: A insulating-piercing connector including a connector main body (A), and a cover (B), and insulating piercing contacts provided in four parallels and spaced rows (2A1, 2A2, 2B1, 2B2) in an insulating support block (1) of the connector main body, said insulating support block including connection wire support inclined bases (3C,3D), said bases being alternately inclined in one direction and then the reverse direction and disposed at a regular distance from one another, each of the contact tails (2) forming said four rows being disposed so that three of said bases in succession are arranged within the width of the contact tail, each of the contact tails forming the second row being arranged so that its center-line is positioned at the center between the centre-lines of the contact tails forming the first row, the contact tails forming the third and fourth rows being shifted by one inclined base from each other, and the heights and inclinations of the inclined bases being selected so that only the parts of the contact tails to be connected with connection wires (3A,3B) project beyond the surfaces of the inclined bases, and the cover includes connection wire support inclined bases (3E,3F) inclined in the reverse direction to those of the connection wire support inclined bases of the connector main body, and includes slots (5) for receiving the contact tails projecting beyond the inclined bases of the connector main body, characterized in that connection wire connecting portions of the inclined bases of the connector main body and those of the cover are formed as curved surfaces (C,D,E,F), and said first and second rows , and likewise said third and fourth rows, of the contact tails are arranged in symmetry with respect to the centers of the curved surfaces thereof, and in that the connection wire support inclined bases of the connector main body and those of the cover are provided with connection wire guide protusions (C',D',E'.F') for guiding the connection wires. An insulation-piercing connector as set forth in claim 1, wherein said curved surfaces (C, D, E, F,) of the connection wire support bases (3C, 3D, 3E, 3F) are circular arcuate surfaces. An insulation-piercing connector as set forth in claim 1, wherein said contact tails (2) have substantially the same width and are fixed to the insulating block (1) to be the same height. An insulation-piercing connector as set forth in claim 1, wherein said connection wire guide protrusions (C', D', E'. F') are formed by smooth extensions of the curved surfaces of the connection wire support inclined bases (3C, 3D, 3E, 3F).

Inventors: IGARASHI YOSHIAKI C O DAIICHI, SAITO YUKIO C O DAIICHI DENSHI, IGARASHI, YOSHIAKI, SAITO, YUKIO, IGARASHI, YOSHIAKI, C/O DAIICHI DENSHI KOGYO K.K., SAITO, YUKIO, C/O DAIICHI DENSHI KOGYO K.K.
Applicants: DAIICHI DENSHI KOGYO, DAIICHI DENSHI KOGYO KABUSHIKI KAISHA
Application year: 1991
Main classification: H01R4
IPC codes: H01R4, H01R12