Insulation displacement connector

Abstract: An electrical connector (100′) has a plurality of contacts (10) positioned in a dielectric housing (20′) for terminating respective electrical wires (1) and a plurality of wire retaining grooves (70) on the housing (20′) for receiving and retaining respective electrical wires (1). Each groove (70) is provided with projections (72a,72b) on respective sidewalls (74). The projections (72a,72b) are positioned at different depths relative to each other.

Description: The invention relates to electrical connectors and more particularly to wire retaining means on such connectors. Connectors have widely been used for conveniently connecting and disconnecting a large number of signal lines. Among many connectors, insulation displacement connectors are known for making electrical connection between the conductor of an insulated electrical wire and a contact by simply forcing the insulated electrical wire into such contact, to break the insulation, thereby eliminating the need for stripping the insulation at the end of the insulated electrical wire in order to solder or crimp the conductor to the contact. Illustrated in Figure 4 is an exploded perspective view of one example of one such conventional insulation displacement connector 100. A large number of contacts 10 are inserted in a large number of grooves 21 provided in a housing 20 at a predetermined pitch. Although not shown in Figure 4, the grooves 21 are also provided in the lower side of the housing 20 to receive contacts 10 from below. The contacts 10 are provided with mating sections 11 at their front portions for making electrical contact with contacts of another matable connector (not shown) and insulation displacement connection (IDC) sections 12 at their rear portions for receiving sections 1a of the insulated electrical wires 1 (see Figure 1) for electrically engaging conductors 2 of the insulated electrical wires 1. On pushing the insulated electrical wires 1 into V-grooves 12a of the IDC sections 12, the insulation layers 3 are severed for making electrical contact with conductor 2. Sections 1b of electrical wires 1 are pushed into wire retention grooves 22 in housing 20 simultaneously with the insertion of end sections 1a into IDC sections 12 of the contacts 10, thereby securing the insulated electrical wires 1 in connector 100. The housing 20 including the insulated electrical wires 1 connected to the contacts 10 in the manner described above is coupled to another housing 30. The assembly is then sandwiched between upper and lower covers 40 (only lower cover is shown in Figure 4) before being covered with a metal cover 50 from the front end to complete the insulation displacement connector 100. Illustrated in Figure 5 is a front view of the electrical wire retention grooves 22 of housing 20 for the insulation displacement connector 100 of Figure 4 as seen from the ends of electrical wires 1. There are formed projections 23 in each electrical wire retention groove 22 adjacent to its entrance in such a manner as to limit the width of the entrance smaller than the diameter of the electrical wire 1. The electrical wires 1 are forced into the respective grooves 22 through the narrower entrance and are retained in the grooves 22 by downwardly facing shoulders 23a of projections 23. Illustrated in Figure 6 is a simplified view of electrical wire 1 just before being inserted into the IDC section 12 of the contact and in the wire retention groove 22 in housing 20. The electrical wire 1 is placed over the IDC section 12 and the wire retention groove 22 and is then inserted into the IDC section 12 and the electrical wire retention groove 22 by tool 60. The insertion tool 60 has grooves 61, 62 at positions corresponding to the IDC section 12 and the electrical wire retention groove 22 so that the electrical wire 1 is pushed down at both sides of both the IDC section 12 and the electrical wire retention groove 22. As described hereinbefore, the electrical wires 1 are inserted and held in the electrical wire retention grooves 22. However, the grooves 22 are forced to widen their entrances by the electrical wires 1 hitting the projections (see Figure 5) when the electrical wires 1 are being inserted in the electrical wire retention groove 22 by the insertion tool 60. This tends to deform the housing 20 downwardly at and near its center portion of the back end portion (lower right portion in Figure 4) as shown by an arrow A. If such deformation occurs, not only the electrical wire retention grooves 22 but also the contacts 10 tend to move in the direction as shown by an arrow B in Figure 6. There may be an instance that the IDC sections 12 move beyond the groove 61 in the insertion tool 60 as shown by the dashed line C. If the insertion tool 60 is operated to push down the electrical wires 1 under this condition, the IDC sections 12 are crushed by the insertion tool 60 and no proper electrical connections can be made between corresponding conductors 2 of the electrical wires 1 and the contacts 10. Also, widening the electrical wire retention grooves 22 may cause misalignment between the pitch of the electrical wires 1 and the IDC sections 12 of the contacts 10 disposed in the housing 20. This may result in the electrical wires 1 riding over the blades 12b of the IDC sections 12 of the contacts 10 (see Figure 4) and cutting the conductors 2 by blades 12b when the electrical wires 1 are pushed down. Illustrated in Figure 7 is a cross section view of another conventional electrical wire retention grooves 22′. The provision of projections 24 extending downwardly at a certain slope as illustrated in Figure 7 rather than the simple projections 23 in Figure 5 may be effective to solve the above problem because the deformation of such projections 24 during insertion of the electrical wires in the grooves 22′ absorbs the force which would otherwise widen grooves 22′. However, in order to enjoy the effectiveness of such downward projections 24, such projections must have a proper length thereby requiring higher raised portions 26 to form the electrical wire retention grooves 22′ and making the insulation displacement connector bulky. There are increasing needs for compact connectors having a large number of signal carrying contacts at a small pitch therebetween. In this case, the width of each raised portion 26 must be small and forming such slanted downward projections is increasingly difficult. In the light of the above problems, it is proposed to provide the present device which is intended to provide an electrical connector free from such deformation and suitable for miniaturization. The present invention consists in an electrical connector as defined in claim 1. A connector according to the preamble of claim is disclosed in DE-U-8617650. US-A-4 653 831 discloses an electrical connector having a plurality of wire retention grooves, facing side walls of which have inwardly extending projections spaced longitudinally apart from each other. Embodiments of the present invention will now be described with reference to Figures 1 to 3B of the accompanying drawings, in which: FIGURE 1 is a perspective view of a part of the housing as well as electrical wires and contacts of the insulation displacement connector according to one embodiment of this invention; FIGURE 3 is a front view of the electrical wire retention grooves of Figure ; FIGURES 3A and 3B are respectively plan and front views of the electrical wire retention grooves of the insulation displacement connector according to another embodiment of the present invention; FIGURE 4 is an exploded perspective view of one example of conventional insulation displacement connectors; FIGURE 5 is a front view of the electrical wire retention grooves in the housing of the insulation displacement connector of Figure 4; FIGURE 6 is a simplified drawing of an electrical wire just before being inserted in the IDC section of the contact and the electrical wire retention groove in the housing; and FIGURE 7 is another example of conventional electrical wire retention grooves. Illustrated in Figure 1 is a perspective view of a part of housing 20′ as well as electrical wires 1 and contacts 10 of one embodiment of the insulation displacement connector 100′. The housing 20′ is equivalent to the housing 20 in Figure 4 and therefore no detailed description is required. The electrical wires 1 are forced into the IDC sections 12 of the contacts 10 disposed in the grooves 21′ and also in the electrical wire retention grooves 70. Figure 2 is a front view of the electrical wire retention grooves 70 illustrated in Figure 1. There are provided a pair of projections 72a, 72b on both sidewalls 74 of each retaining groove 70 at different depth positions. The electrical wires 1 tend to widen the electrical wire retention grooves 70 upon hitting the projections 72a, 72b. The projections 72a, 72b, however, being shifted in the direction of insertion, thereby minimizes the force which would otherwise widen the grooves 70 and thus effectively avoid the aforementioned problems associated with the deformation of the conventional housing grooves 22. Also, the electrical wire retention grooves 70 are simple in shape as compared with the electrical wire retention grooves 22′ in Figure 7 and are simpler to manufacture. Illustrated in Figures 3A and 3B are plan and front views of electrical wire retention grooves 80 in accordance with another embodiment of connector 100′. The projections 82a,82b provided on both sidewalls 84 of the electrical wire retention grooves 80 are not only shifted in the depth direction but also in the length direction (vertical direction in Figure 3A) of the electrical wire retention grooves 80. In this particular configuration, the force to widen the electrical wire retention grooves 80 during insertion of the electrical wire 1 therein is further distributed to suppress deformation of the housing. As described in detail hereinbefore, the insulation displacement connector according to the present device features the provision of the projections on the both sidewalls of each electrical wire retention groove at different depth positions therealong. The force to widen each electrical wire retention groove during insertion of the electrical wires into the electrical wire retention grooves is effectively distributed to minimize deformation of the housing. Also the wire retention grooves are simple and suitable for miniature connectors.

Claims: An electrical connector (100′) of the type having a dielectric housing (20′) a plurality of contacts (10) disposed in the housing (20′) and having termination means (12) for electrically terminating respective electrical wires (1) and further the housing (20′) including a plurality of wire retention grooves (70,80) for receiving respective electrical wires (1), wherein inwardly extending projections (72a,72b,82a,82b) are provided on facing side walls (74,84) of each groove (70,80) with respective projections (72a,72b,82a,82b) in each groove (70,80) being positioned at a different depth relative to each other, characterized in that said projections (72a,72b,82a,82b) are arcuate. The electrical connector (100) according to claim 1 further characterized in that respective projections (82a,82b) are spaced longitudinally apart relative to each other.

Inventors: KASHIWA YOICHI, KASHIWA, YOICHI
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1990
Main classification: H01R23
IPC codes: H01R12, H01R4, H01R13, H01R9