Connector for flat cables

Abstract: A connector for a flat cable having a hollow casing with a cavity therein. The cavity receives a leading end of the flat cable through a front opening in the casing. The cable has a plurality of flat terminals on both sides of the leading end. Complementary front and rear terminals are inserted into the cavity from front and rear openings in the casing. Each set of terminals contacts one side of the leading end of the cable. The leads from each set of terminals extend outwardly of the casing in opposite directions, thereby reducing the density of leads and facilitating assembly thereof.

Description: The present Invention is directed to a connector for flat cables; more specifically, to a connector adapted for use with flat cables which have terminals on both faces thereof. BACKGROUND OF THE INVENTION Previously known connectors for flat cables are exemplified by Japanese OPI 4/206374. As shown in Figures 10 and 11, flat cable 1 carries terminals 2 on both faces of its end. Cable connector 3 is provided with slit 4 into which terminals 2 are inserted. As shown particularly in Figure 11, cable 1, after passing through slit 4, is located between connecting terminals 5. Terminals 5 extend out of the front of connector 3 and are adapted to be connected to other terminals (not shown). As can be seen in Figure 10, terminals 5 are arranged in two, spaced apart rows, complementary to terminals 2. Each row contacts terminals 2 on one face of flat cable 1. The terminals are biased toward each other so that, when terminals 2 are inserted therebetween, good electrical contact is made. In this construction, due to the large number of terminals 5 which extend from the front surface of cable connector 3, wiring is extremely difficult. Moreover, the opportunities for error are increased because there is not much room between adjacent terminals. EP-A-0 519 317 discloses a connector having the features recited in the preamble of claim 1. In this prior art connector the casing has support shelves for supporting the inserted leading end of the flat cable on both sides thereof at portions which are spaced the longitudinal direction of said leading end. The front contacts and rear contacts are also spaced from each other in the longitudinal direction of the cable end and are each arranged opposite a corresponding support shelve. Thus, the leading end of the cable is contacted at two points which are spaced in the longitudinal direction thereof, namely between the front terminals and a corresponding support shelf and between the rear terminals and a corresponding support shelf. EP-A-0 667 651 discloses a connector for a flat cable having a support shelf for supporting the underside of the inserted leading end of the cable, and a plurality of rear terminals having rear contacts extending over the flat cable end and making contact therewith. It is an object of the present invention to provide a cable connector for flat cables, wherein the density of flat terminals is substantially reduced, even though the total number of such terminals remains the same, and wherein the size of the connector is not materially increased and where good electrical contact between the cable and the front and rear terminals of the connector is obtained. For achieving this object the invention provides a connector as defined in claim 1. The dependent claims relate to further advantageous features of the invention. The inventive connector is provided with a hollow casing having a cavity therein. The cavity extends from a front opening in the casing to a rear opening remote therefrom. The front opening is a slit which is complementary to the leading end of the flat cable. The cable is provided with a plurality of flat terminals adjacent the leading end and on both sides thereof. The casing contains a similar plurality of front terminals, corresponding to the flat terminals. The front terminals are inserted through the front opening into the cavity and are adapted to contact the flat terminals on one side of the leading end. The casing also contains a plurality of rear terminals, corresponding to the flat terminals, which have been inserted through the rear opening into the cavity. These terminals are adapted to contact the flat terminals on the other side of the leading end. The spacing between the front and rear terminals is smaller than the thickness of the leading end. Thus, when the cable is passed through the slit between the front and rear terminals, good electrical contact is made therewith. The present Invention provides a plurality of front leads, each of which is in electrical contact with one of the front terminals and extends through the front opening and out of the casing. Similarly, there is provided a plurality of rear leads, each in electrical contact with one of the rear terminals and extending out of the casing through the rear opening. To insure good electrical contact between the front and rear terminals on the one hand and the two sets of flat terminals on the other according to the invention the front and rear terminals are biased toward one another. Therefore, if the flat cable is inserted, a certain amount of pressure is required to force the front and rear terminals apart; this has a tendency to cause abrasion, particularly of the flat terminals. In order to overcome this difficulty according to a preferred embodiment, a retainer, carrying a planar plate which is generally parallel to the planes of all of the terminals, is provided. The plate can be introduced into the cavity to deflect the front or rear terminals and thereby increase the separation between them. This permits introduction of the flat cable without risk of abrasion or damage. In a desirable form of the Invention, the plate is provided with a plurality of grooves extending completely therethrough. The grooves correspond to either the front terminals or the rear terminals and extend longitudinally toward - but terminate short of - the distal end of the plate. Thus, as the distal end of the plate is inserted through the front opening, it contacts either the front terminals or the rear terminals. The pressure thereof deflects one set of the terminals so as to increase its separation from the other set. At this point, with the retainer in this initial position, the flat cable can easily be inserted without contacting either the front or rear terminals. Thereafter, the plate is moved from the initial position further into the cavity to an operative position. In the latter, the terminal contacted by the distal end rides thereover and, due to its resilience, passes through the groove so that it is at or adjacent the other terminal, thereby providing good electrical contact between the front terminals and the flat terminals, as well as between the flat terminals and the rear terminals. To secure the front terminal in the casing, a front fixing hole is provided. A front positioning piece is affixed to or integral with the front terminal. Analogously, a rear fixing hole is provided which can receive a rear positioning piece affixed to or integral with the rear terminals. Thus, the insertion of the positioning pieces of the front and rear terminals secures them in the casing. As further refinements of the present Invention, the front or rear terminal being deflected by the plate carries an inclined entry face against which the distal end presses. This assists in causing the deflection of the terminal. This face inclines upwardly in the entry direction of the plate. The terminal also has an inclined withdrawal face which angles downwardly in the aforementioned entry direction. Thus, on insertion, the distal end first rides up the entry face (thereby separating the terminals) and then rides down the withdrawal face, permitting the terminal to pass through the groove and approach the other terminal. When the plate is withdrawn, the action between the distal end and the inclined faces is the reverse of that described above. It has been found advantageous to modify the retainer by providing a base to which the plate is attached. The base has a configuration corresponding to the front opening so that, when the plate is in its operating position, the base covers the front opening and prevents entry of undesired contaminants. In another embodiment of the Invention, the retainer has a flat surface and a wall depending from the trailing edge thereof. A lip extends from the depending wall in a direction toward the leading edge of the retainer and is spaced apart from the flat surface, thereby providing a U-shaped cross section. The distal edge of the lip contacts and deflects the rear contact when the edge is fully inserted into the cavity. Preferably, there are inclined mating surfaces which facilitate the movement of the rear terminal away from the front terminal. In this position, the flat cable is readily inserted without risk of damage. Thereafter, the retainer is moved to an operative position wherein the lip releases the rear terminal which is biased toward the front terminal. As a result, the flat terminals on the leading end of the cable are firmly contacted by the front and rear terminals, thus insuring a good electrical connection. It has also been found useful to provide the base with a pair of spaced apart arms which are adapted to slide in complementary guide grooves on the walls of the casing. In addition, projections and detents can also be provided whereby the retainer is releasably locked in the desired operative position. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, constituting a part hereof and in which like reference characters indicate like parts, Figure 1 is a front perspective view of one embodiment of the present Invention; Figure 2 is a longitudinal partial cross section of the connector of Figure 1 with no flat cable inserted; Figure 3 is a view similar to that of Figure 2 with the flat cable inserted; Figure 4 is an exploded perspective view of another embodiment of the present Invention; Figure 5 is a longitudinal partial cross section of the connector of Figure 4 with the flat cable partially inserted; Figure 6 is a view similar to that of Figure 5 wherein the flat cable is fully inserted; Figure 7 is a perspective view of a third embodiment of the present Invention; Figure 8 is a longitudinal partial section through the connector of Figure 7; Figure 9 is similar to Figure 8 with the cover in operative position; Figure 10 is a perspective view of a prior art cable connector; and Figure 11 is a longitudinal partial cross section of the connector of Figure 10. Referring to Figures 1 to 3, the connector of the present Invention comprises casing 20 having slit 21 on the front thereof. Flat cable 10 consists of film 11 and carries circuits 12 ending in flat terminals 13. Front terminals 30 correspond in number and location to flat terminals 13 on one side of cable 10. Circuits 12 and terminals 13 can be formed in any known manner; e.g. circuits 12 can be placed on one side only of film 11 and the end thereof folded over so that terminals 13 are on both sides. The end of cable 10 can be made of stiffer or stronger material than the remainder thereof, a protective cap may be placed thereon which will leave only terminals 13 exposed, etc. There is no requirement that the end be flexible; for the purposes of the present Invention, the end need only have terminals 13 on both sides. Front terminals 30 consist of front lead 32, front contact 33, and positioning piece 31. Analogously, rear terminals 40 are made up of rear lead 42, rear contact 43, and positioning piece 41. Positioning pieces 31 and 41 fit into fixing holes 22 as shown in Figures 2 and 3. The distance between the distal ends of contacts 33 and 43 is preferably somewhat shorter than the thickness of cable 10. Referring more specifically to Figure 3, cable 10 is inserted through front opening 21 into the cavity in casing 20. The flat terminals on either side of cable 10 are contacted by front contact 33 and rear contact 43, thus completing circuits 12. Leads 32 and 42, which extend out of casing 20, are used to make electrical connections to other circuitry, such as that to be found on a circuit board. It is a feature of the present Invention that leads 32 and 42 are not concentrated on one surface of casing 20, but rather extend both forwardly (leads 32) and rearwardly (leads 42). By decreasing the concentration of the leads, wiring and connection are made simpler and less prone to error. Another embodiment of the present Invention is shown in Figures 4 to 6. In this modification, retainer 50 is comprised of base 52 and arms 53 which have projections 53a at their distal ends. Complementary guide grooves 23 are located on the sides of casing 20 and are provided with projections 23a and 23b. As retainer 50 is slid onto casing 20, arms 53 move in guide grooves 23 and projection 23b cooperates with projection 53a to hold retainer 50 in its initial position. When retainer 50 is fully mounted on casing 20, projections 23a engage projections 53a, thereby securing retainer 50 in its operative position. Retainer 50 carries plate 51 which contains grooves 51a extending therethrough. Grooves 51a terminate short of the distal edge of plate 51. Retainer 50 is mounted on casing 20 in its initial position; the distal edge of plate 51 bears against the upwardly slanted surface of front terminal 30, thus deflecting it downward (as shown in Figure 5) and separating front terminal 30 from rear terminal 40 by a distance which is preferably greater than the thickness of flat cable 10. Cable 10 is then inserted all the way into the cavity in casing 20. This can be done easily, since terminals 30 and 40 are sufficiently separated so that no pressure is exerted on the end of cable 10. Thereafter, as shown in Figure 6, retainer 50 is fully inserted into its operative position. As the distal edge of plate 51 passes beyond the distal end of front terminal 30, the latter is released and passes through grooves 51a to bear against cable 10. As a result, cable 10 is firmly held in casing 20 and good electrical contact between terminals 30 and 40 and the flat terminals on the end of cable 10 is maintained. A further modification of the present Invention is shown in Figures 7 to 9. Cover 60 is adapted to slide over casing 20 and is provided with depending wings 61 having guide holes 61a. Complementary projection 24 is formed on the side of casing 20. Front leads and rear leads extend outwardly from the front and rear faces of the connector, respectively. Cover 60, at its front end, is provided with a depending portion and an inturned lip. The undersurface of cover 60, the depending portion, and the inturned lip form cavity 62. As cover 60 slides onto casing 20, the leading edge of the lip contacts the distal end of rear terminal 40. As shown in Figure 8, when cover 60 is in its left-most position, the lip raises terminal 40 and increases the separation between it and front terminal 30. This, in a similar manner to the previous embodiment, permits the introduction of the cable (not shown) into the connector without pressure or abrasion. Thereafter, as shown in Figure 9, cover 40 is moved to the right and rear contact 43 is released by the lip and returns to its normal position adjacent front terminal 30. The present Invention, by dividing the external leads between two surfaces of the connector, provides more space therebetween and facilitates both assembly and production. Preferably, the front and rear terminals are three-pronged in shape having leads, positioning pieces, and contacts; however, this shape is not critical. The connectors in accordance with the present Invention are well adapted to be placed on a printed circuit board and the leads readily soldered thereto. This can be accomplished (for example) by applying solder paste to the appropriate positions on the circuit board and mounting casing 20 thereon. This is followed by exposure to the appropriate atmosphere, whereby soldering is complete. Although only a specific number of embodiments of the present Invention have been expressly described, its scope is not to be limited by the embodiments but only by the claims appended hereto.

Claims: A connector for a flat cable (10) said cable having a leading end provided with a plurality of flat terminals (13) on both sides of said leading end, said connector comprising: a casing (20) having a cavity therein, said cavity extending from a front opening (21) in a front of said casing to a rear opening in a rear of said casing, said rear opening being remote from said front opening, said cavity adapted to receive said leading end of said cable (10) through said front opening, a plurality of front terminals (30), complementary to said flat terminals (13), in said cavity and inserted through said front opening (21), said front terminals (30) having front contacts (33) extending toward said rear and adapted to contact said flat terminals (13) on one side of said leading end, a plurality of rear terminals (40), complementary to said flat terminals (13), in said cavity and inserted through said rear opening, said rear terminals (40) having rear contacts (43) extending toward said front and adapted to contact said flat terminals (13) on the other side of said leading end, characterized in that a plurality of front leads (32) are provided, each in electrical contact with at least one of said front terminals (30) and extending out of said casing at said front, and a plurality of rear leads (42), each in electrical contact with at least one of said rear terminals (40) and extending out of said casing at said rear, and in that said front contacts (33) of the front terminals (30) and said rear contacts (43) of the rear terminals (40) are arranged to form a slit therebetween with a spacing distance over said slit which is smaller than the thickness of said leading end of the cable (10), such that said front contacts (33) and said rear contacts (43) make electrical contact with said leading end when said leading end is in the slit between the front contacts (33) and rear contacts (43). The connector of Claim 1, comprising at least one front fixing hole (22) in said casing (20), adapted to receive a front positioning piece (31), at least one rear fixing hole (22) in said casing (20), adapted to receive a rear positioning piece (41), said front positioning piece (31) affixed to one of said front terminals (30), and said rear positioning piece (41) affixed to one of said rear terminals (30). The connector of Claim 1 or 2 comprising a retainer (50, 60) having a plate (51) extending in a direction toward said front terminals or said rear terminals, said plate (51), when inserted into said cavity in an initial position, deflecting at least one of a front contact (33) on said front terminal (30) and a rear contact (43) on said rear terminal (40), thereby to increase said distance between said front contact (33) and said rear contact (43). The connector of Claim 3 wherein said plate (51) is provided with a groove (51a) corresponding to said front contact (38) or said rear contact (43), said groove (51a) extending through said plate (51) and terminating before a distal end thereof whereby, as said plate (51) is inserted into an initial position in said cavity, said distal end deflects said front contact (33) or said rear contact (43), thereby increasing said distance, and as said plate (51) moves from said initial position further into said cavity to an operative position, said front contact (33) or said rear contact (43) passes over said distal end and passes through said groove (51a), thereby reducing said distance to less than a thickness of said leading end. The connector of Claim 1 comprising a retainer (60) of generally planar form on said casing, said retainer (60) having a flat surface, a depending wall at a trailing edge of said flat surface, and a forwardly extending lip on said depending wall, said lip being spaced apart from said flat surface and forming a receiving portion (62) of said cavity, a distal edge of said lip adapted to contact and deflect a front contact (33) on said front terminal (30) or a rear contact (43) on said rear terminal (40) when said edge is fully inserted into said cavity, thereby increasing a distance between said front contact (33) and said rear contact (43). The connector of Claim 5 wherein said lip is out of contact with said front contact (33) and said rear contact (43) when said retainer (G0) is at least partially withdrawn from said cavity. The connector of Claim 3 wherein said retainer (50) comprises at least one arm (53) adapted to slide in a complementary guide groove (23) on a wall of said casing. The connector of Claim 7 wherein each said guide groove (23) contains a first projection (23), each of said arms having a complementary detent (53a), said detent (53a) releasably locking said retainer (50,60) on said casing (20) when said retainer (50,60) is in said operative position. The connector of Claim 7 or 8 wherein each said guide groove (23) contains a second projection (23a), said detent (53a) releasably holding said retainer (50,60) on said casing (20) in said initial position.

Inventors: CHISHIMA MASAMITSU, NAKAMURA HIDETO, NORO YUTAKA, CHISHIMA, MASAMITSU, NAKAMURA, HIDETO, NORO, YUTAKA
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1996
Main classification: H01R12
IPC codes: H01R24, H01R12