Connector for flat cable

Abstract: The number of lead wires is to be increased without increasing the width of a connector (20) for a flat cable. A flat shaped housing (10) of the connector is provided with a slit-like opening (11). As a first group of electrodes, an earthing plate (12) is provided on a bottom surface (11a) in the opening (11), and as a second group of electrodes, electrodes (13) are arranged between the earthing plate (12) and a ceiling surface (11b) of the opening (11). A retainer plate (20) has a thin plate part (21) which can be inserted in between the electrodes (13) and the ceiling surface (11b). The thin plate part (21) has a ribs (25, 26, 27) projecting to the side of the electrodes (13). When the retainer plate (20) is inserted in between the electrodes (13) and the ceiling surface (11b), the ribs (25, 26, 27) project between the electrodes (13) to guide a flat cable (30) to be inserted into the opening (11) benath the thin plate part (21) to the underside or lower face of the electrodes (13). Thereafter, when the retainer plate (20) is pushed in, contact areas of the flat cable (30) become conductive on both surfaces, namely with the earthing plate (12) on the side of the lower surface and with the electrodes (13) on the upper surface. This makes it possible to increase the number of the lead wires without increasing the width of the connector or the cable.

Description: The present invention relates to a connector for a flat cable, and more particularly, to a connector for a flat cable for connecting the ends of a flat cable which is formed in a film state according to the preamble of claim 1. A conventional connector for a flat cable is shown in Fig. 4. In Fig. 4, a housing 1 having a slit-like opening has a plurality of electrodes 3 on an inner peripheral surface 2 which extends in the direction of the housings width. A retainer plate 4 is formed as a thin plate which can be inserted into the housing 1 and has a section substantially in form of a wedge. A flat cable 5 is formed by holding a plurality of flat lead wires with a film. At the foremost end part, each lead wire is exposed at one surface by peeling off the film. With the exposed lead wires directed to the side of the electrode 3, the flat cable 5 in film form is inserted into the housing 1, and the retainer plate 4 is inserted along the side surface of the flat cable 5 being opposite to the lead wires. As the wedge shaped retainer plate 4 is pushed in, the exposed lead wires of the flat cable 5 are pressed against the electrodes 3 and electrically connected therewith under a predetermined contact pressure. In the conventional connector for a flat cable as described above, each of the electrodes 3 is disposed in a manner to face only one surface of the flat cable 5, and the number of the lead wires is limited depending from the width of the flat cable 5. Thus, in order to increase the number of the lead wires, the width of the flat cable 5 has to be increased. Document EP 0 601 577 A discloses an electrical connection element of a connector for electric ribbon wire. There, the ribbon wire having an exposed portion on one side thereof which may be inserted into the connector. Then, a retainer is pushed from a provisionally retained position deeper into the housing of the connector to the completely retained position so that the tape wire is wedged by the wedge portion into a firm contact with a contact surface formed on the lower side of a projection of an upper arm of the electrical connection element to achieve an electrical contact. In view of the problems as described above, the present invention has been made, and its object is to provide a connector for a flat cable wherein the number of the lead wires can be increased without increasing the width of the flat cable. This object is solved by a connector for a flat cable as defined in claim 1. Accordingly, the first electrode arrangement is held along one, e. g. the lower, of the two broad width inner peripheral surfaces in the housing having a slit-form opening, and the group of second electrodes is held in a distance thereto along the other, the upper, inner peripheral surface. Accordingly, by inserting a flat cable having lead wires on both surfaces between the first electrodes and the second electrodes, and then inserting the retainer plate between the group of second electrodes and the other inner peripheral surface to make an electric contact, electric conduction can be obtained to both faces or sides of the flat cable. As a gap is formed between the group of second electrodes and the upper inner peripheral surface, there is a possibility for the flat cable to go into the gap during inserting. However, on the surface of the retainer plate facing towards the group of second electrodes there is formed the rib which enters between the electrodes in the group of second electrodes, said rib projecting downward from the space between the group of second electrodes. Accordingly, the flat cable cannot advance towards the upper inner peripheral surface beyond the group of second electrodes, nor can enter into the gap between the upper inner peripheral surface and the group of second electrodes. As described above, according to the present invention, electric contact and thus conduction can be obtained on both surfaces of the flat cable. Thus, in comparison with the case of only one contactable surface, the number of the lead wires can be increased (e.g. doubled) without increasing the width of the flat cable. Also, entry of the flat cable into the insertion space of the retainer plate can be prevented. In this manner, there can be provided a connector for a flat cable having an increased contact number and a reliable function. In an advantageous modification of the present invention as defined in claim 3, the connector has a constitution wherein the retainer plate provided with a recess to accommodate the foremost ends of the electrodes of the group of second electrodes on the surface of the retainer plate facing towards the group of second electrodes. From the recess the rib projects or ribs project between the elctrodes of the group of second electrodes. Therefore, the group of second electrodes is in a closer position to the retainer and the rib projects more clearly. Thus the rib or ribs surely prevent the flat cable from advancing upwards beyond the group of second electrodes and entering into the gap between the group of second electrodes and the upper inner peripheral surface. Due to the advantageuos modification of the invention it becomes easier for the group of second electrodes to approach to the retainer plate, and it is possible to prevent the flat cable from slipping into the gap for the retainer plate. The further subclaims are directed to further advantageous modifications of the present invention. This invention and its further advantages can be more fully understood from the following illustrative description, which is to be taken in conjunction with the accompanying drawings, in which: Fig. 1 is a sectional view of the connector for a flat cable according to an embodiment of the present invention with the retainer plate partly inserted; Fig. 2 is a perspective view of the retainer plate turned by 180° upside down; Fig. 3 is a sectional view of the embodiment shown in Fig. 1 with the retainer plate fully inserted; and Fig. 4 is a sectional view of a conventional connector for a flat cable. Fig. 1 shows an exemplifying embodiment of a connector for a flat cable according to the present invention by way of a sectional view. A housing 10 formed in flat longitudinal shape has a slit-form opening 11, into which a retainer plate 20, having a thin plate part 21, and a flat cable 30 can be inserted. In the drawing, the housing 10 is equipped with an earthing plate 12 as a first electrode arrangement on the side of a bottom surface or lower inner inner peripheral surface 11a in the opening 11. The bottom surface 11a is terminated by a vertical part 17 which abuts with the end 16 of flat cable 30. The vertical part 17 is terminated by a horizontal part 18 extending parallel to the bottom suface 11a. From the horizontal part 18 electrodes 13 as a group of second electrodes extend into between the earthing plate 12 and a ceiling surface or an upper inner peripheral surface 11b. Between the electrodes 13 and the ceiling surface 11b a space 14 extends into which the thin plate part 21 of the retainer plate 20 is inserted. Between the electrodes 13 and the earthing plate 12 a space 15 extends into which the cable 30 is inserted. The individual electrodes 13 of said plurality of electrodes are arranged in parallel to each other, and they are respectively bent downward in a crank form at the end face of the opposite side to the opening 11, thus being extended in parallel with the earthing surface 12 of the housing 10. In this embodiment, the first electrode arrangement is constituted by the single earthing plate 12, but there may be a constitution to arrange a plurality of individual electrodes (like the electrodeds 13) in a widthwise direction as the first group of electrodes; this depends from the kind of flat cable 30 used. The retainer plate 20 is, as shown in Figs. 1 and 2, is provided with a thin plate part 21 of approximately wedge shape in section, which can be inserted in the space 14 between the electrodes 13 of the group of second electrodes and the ceiling surface 11b; and lock arms 22 and 23 at both lateral ends of the thin plate part 21, which are engageable with the outer lateral surface of the housing 10. By the lock arms 22, 23 the retainer plate 20 is temporarily locked to the housing 10, when its foremost end is set into space 14 between the electrodes 13 and the ceiling surface 11b. In the present embodiment, the lock arms 22, 23 are to be locked to the outer peripheral surface of the housing 10, but it is not essentially necessary to hold the retainer plate 20 with the lock arms. There may be a construction having at least only the thin plate part 21 to be inserted into the slit-form opening 11. Also, in the present embodiment, due to the inside of the opening 11 and the thin plate part 21 becoming thinner in depth-wise direction or inserting direction, a contact pressure is obtainable depending from the pushing-in motion or degree, respectively, of the retainer plate 20. However, it is not essentially necessary for these two members to have a wedge form, but they may be so designed as to obtain a contact pressure according to the advance in depth-wise direction by a cam groove or the like formed on the lateral side. On the side of the thin plate part 21 facing or being adjacent to the electrodes 13, there is formed a recess 24 into which the foremost ends of the electrodes 13 can enter. As shown in Fig. 2, recess 24 comprises two parts 24a and 24b and is formed in the surface of the thin plate part 21 to be be open in inserting direction of the thin plate part 21. In insertion direction the periphery of the recess 24 and the two parts 24a and 24b, respectively, constitutes three ribs 25, 26 and 27, a left 27 and a right 25 lateral side rib and a middle rib 26. The intermediate or middle rib 26 is made to enter into the space between two of the electrodes 13 which are arranged in parallel. In this embodiment, by forming the recesses 24a and 24b, the peripheries of them are made to swell up, so that the ribs 25, 26 and 27 are formed. However, it is not essentially necessary to form the recesses 24a and 24b for having the ribs 25, 26, and 27 but the ribs may be formed independently. The ribs 25, 26, and 27 may not be limited to the ones as shown, which swell or increase in thickness continuously, but may swell intermittently or project like a pillar on a spot. Next, the operation of the embodiment shown in Figs. 1 to 3 having the above constitution is explained. The foremost end of the thin plate part 21 of the retainer plate 20 is inserted into the space 14 between the electrodes 13 in the slit-shaped opening 11 and the ceiling face 11b. Under this state, the lock arms 22 and 23 are stopped on the outer lateral surface of the housing 10, so that the retainer plate 20 is held in position. The foremost end of each of the electrodes 13 is positioned slightly inside the recesses 24a and 24b formed in the thin plate part 21, and the middle rib 26 formed on the thin plate part 21 projects between two of the electrodes 13. This condition is shown in Fig. 1. After the above step, the foremost end 16 of the flat cable 30 is pushed into the opening 11 under the underside of the retainer plate 20. There may be cases for the flat cable 30 to be inserted with its foremost end directed or bent upward, but when it is pushed in with such an upward position, the bent end runs against the ribs 25, 26, and 27 projecting from the thin plate part 21 of the retainer plate 20. As described above, because the middle rib 26 projects between two of the electrodes 13, and the foremost ends of the electrodes 13 lie within the recesses 24a and 24b, so that the middle rib 26 projects even deeper downward beyond the two adjacent electrodes 13, the flat cable 30, as it is pushed in as such, is naturally forced downward under the electrodes 13. In other words, it does not occur for the flat cable 30 to be pushed in with its end 16 being bent upward more than the electrodes 13 are arranged in height. After the flat cable 30 has been pushed in to the desired depth, the retainer plate 20 is pushed in. Owing to the sectional shapes of the retainer plate 20 and the opening 11, as the retainer plate 20 is pushed in, the electrodes 13 are forced down, and the flat cable 30 is held between the electrodes 13 and the earthing plate 12 to obtain electric contact and conduction. This state is shown in Fig. 3. In the fully inserted state of the retainer plate 20 the electrodes 30 are arranged between the left and right ribs 25 and 27. This construction avoids that the outermost electrodes 13 of the group of second electrodes are bent to the left or right side by the flat cable 30 to be inserted. upon insertion. Thus proper electrical contact of the outermost electrodes 13 with the correspondig terminals of the flat cable 30 is given. As described above, a flat shaped housing 10 is provided with a slit-like opening 11. As the first electrode arrangement, an earthing plate 12 is provided on the bottom face 11a in said opening 11, and as the group of second electrodes, the electrodes 13 are set between it and the ceiling face 11b. The retainer plate 20 has a thin plate part 21 which can be inserted in between the electrodes 13 and the ceiling face 11b, and the thin plate 21 has middle rib 26 projecting to the side of the electrodes 13. When the retainer plate 20 is inserted in between the electrodes 13 and the ceiling face 11b, the rib 26 projects between two of the electrodes 13 to guide the end of cable under the lower face of the electrodes 13 into space 15 during insertion of the flat cable 30 beneath the retainer plate 20. Thereafter, when the retainer plate 20 is pushed in, the foremost end 16 of the flat cable 30 becomes connected double, i.e. to the earthing plate 12 on its lower face side and to the electrodes 13 on its upper face side. This makes it possible to increase the number of the lead wires without increasing the width of the cable.

Claims: A connector for a flat cable (30) comprising a housing (10) having a slit-like opening (11) and an upper (11b) and a lower (11a) broad width inner peripheral surface; electrodes, and a retainer plate (20) having a thin plate part (21) to be inserted into the slit-like opening (11) of the housing (10), characterized in that it further comprises: a first electrode arrangement (12) disposed along the lower inner peripheral surface (11a); a group of second electrodes (13) disposed within the slit-like opening (11) with an upper space (14) between the upper inner peripheral surface (11b) and the group of second electrodes (13) and with a lower space (15) between the first electrode arrangement (12) and the group of second electrodes (13); wherein said thin plate part (21) of the retainer plate (20) is to be inserted into the upper space (14) between the group of second electrodes (13) and the upper inner peripheral surface (11b), and wherein said thin plate part (21) having at least one rib (25, 26, 27) facing towards the lower inner peripheral surface (11a) and extending in direction parallel to the insertion direction of the retainer plate (20) into the opening (11), said at least one rib (25, 26, 27) entering into between the electrodes (13) of the group of second electrodes. A connector for a flat cable according to claim 1, wherein a plurality of said ribs (25, 26, 27) is provided with the two outermost ribs (25, 27) having the group of second electrodes (13) between them. A connector for a flat cable according to claims 1 or 2, wherein the thin plate part (21) is partially provided with said ribs (25, 26, 27) by forming recesses (24a, 24b) between the ribs to accommodate the foremost ends (16) of the electrodes (13) of the group of second electrodes on the surface of the thin plate part (21) facing towards the lower inner peripheral surface (11a). A connector for a flat cable according to anyone of the preceding claims, wherein the retainer plate (20) comprises lock arms (22, 23) to lock the retainer plate (20) to the outer peripheral surface of the housing (10). A connector for a flat cable according to anyone of the preceding claims, wherein the housing (10) comprises temporarily lock means to engage with the lock arms (22, 23), when the retainer plate (20) is partly inserted into the slit-like opening (11).

Inventors: ITO TOMONARI, ITO, TOMONARI, Ito, Tomonari, Sumimoto Wiring Systems, Ltd.
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1996
Main classification: H01R12
IPC codes: H01R13, H01R12