A connector for a circuit board

Abstract: To ensure the strength of a tubular engaging portion and to prevent a breakage of a locking portion during the connection with a mating connector. When a terminal fitting 20 is inserted to a proper position in a tubular engaging portion 11, locking portions 33 formed on the outer surfaces of the terminal fitting 20 are engaged with lock recesses 18 formed in the inner surfaces of the engaging portion 11, with the result that the terminal fitting 20 is held so as not to come out. The locking recesses 18 are formed by recessing small portions of the inner surfaces of the engaging portion 11 sufficient to be engaged with the leading ends of the locking portions 33 and, accordingly, do not bring about a reduction in the strength of the engaging portion 11. Further, since the locking portions 33 do not project from the outer surfaces of the engaging portion 11, there is no likelihood that the locking portions 33 are broken when a mating connector is fitted on the engaging portion 11.

Description: The present invention relates to a connector for a circuit board. A known connector for a circuit board is disclosed in Japanese Utility Model Registration No. 2542233. This connector is provided with a housing 1 (see FIG. 7) made of a resin to be fixed to a circuit board (not shown). The housing 1 is formed with a tubular engaging portion 2 into which a terminal fitting (not shown) is inserted from behind and on which a mating connector (not shown) is fitted from front, and with locking portions 3 for locking the terminal fitting in the upper and lower surfaces of the tubular engaging portion 2. The locking portions 3 are formed between a pair of slits 4 extending backward from the front edge of the tubular engaging portion 2 so as to project forward. During the insertion of the terminal fitting, the locking portions 3 are so elastically deformed as to bulge out from the outer surfaces of the engaging portion 2 by the engagement of lock projections 3A thereof with the outer surfaces of the terminal fitting. When the terminal fitting is inserted to its proper position, the lock projections 3A are engaged with lock holes formed in the terminal fitting as the locking portions 3 are restored inwardly, with the result that the terminal fitting is held so as not to come out. In the above prior art connector for a circuit board, since the slits 4 for defining the locking portions 3 elongate in forward and backward directions, the tubular engaging portion 2 is not a complete tube having a continuous outer surface over its entire circumference and, accordingly, cannot have a sufficient strength. Therefore, the engaging portion 2 is liable to be deformed and cannot securely protect the terminal fitting. Further, the locking portions 3 bulge out from the engaging portion 2 if the terminal fitting is insufficiently inserted. Accordingly, if the mating connector is fitted on the engaging portion 2 in this state, it is brought into contact with the leading ends of the locking portions 3, which may in turn be broken. US-A-4 846 711 shows a connector having a flange that projects transversely from a barrel portion. A locking portion is formed at a location on the flange remote from the barrel portion. WO-A-86/00 473 shows a connector having a housing with locking recesses at the front part of a connecting portion, and a temrinal fittng with locking portions at the front part of a connecting portion. It is an object of the present invention to provide a connector mounted on a circuit board which has a high durability and cannot easily be broken in particular during the connection process with a mating connector. This object is solved according to the invention by a connector having the features disclosed in claim 1. Preferred embodiments of the invention are subject of the dependent claims. According to the present invention there is provided a connector which ensures the strength of an engaging portion and prevents locking portions from being broken during the connection with a mating connector. According to the invention, there is provided a connector mountable on a circuit board with a terminal fitting mounted in a housing thereof, comprising: a engaging portion provided on or at the housing for permitting a mating connector to be fitted on a front portion from a mating direction, a connection section provided on or at the terminal fitting, the connection section being at least partially inserted from an insertion direction along the substantially inner surface of the engaging portion so as to enable the connection with a mating terminal fitting of the mating connector, and a locking means provided on or at the housing and the terminal fitting for substantially preventing the connection section from being disengaged from the engaging portion, wherein the locking means comprises at least one lock recess formed in or on the inner surface of the engaging portion and at least one corresponding locking portion on the connection section, which projects at an angle different from 0° or 180° with respect to the connection section and has a leading end engageable with the lock recess, and wherein the terminal fitting comprises connection portions to be directly connected to the circuit board, and wherein the lock recess is formed in a rear end posifion of the engaging portion when viewed from the mating direction and the locking portion is disposed at the rear end of the connection section when viewed from the mating direction. Since the lock recess is provided in the rear end position, an area having a high strength stretches over a wide range of the tubular engaging portion from the front end to a middle portion. This enables a secure protection of the tubular connection section. Further, the terminal fitting is allowed to have a sufficient length before the lock recess for the formation of the locking portion. Thus, the reliability of the terminal fitting locking function can be improved by making the locking portion larger. According to a preferred embodiment, the lock portion projects obliquely backward from the connection portion. Preferably, the locking portion is formed by cutting a portion of the connection section and bending a cut portion obliquely backward. Accordingly, the locking portion can be formed at a low cost in a way effectively preventing the connection section from being disengaged from the engaging portion. Further preferably, the locking portion is elastically deformable. Most preferably, the engaging portion is substantially tubular and/or wherein the connection section is substantially tubular. Accordingly, a construction having an even higher strength can be provided. According to a further preferred embodiment, there is provided a connector mountable on a circuit board with a terminal fitting mounted in a housing thereof, further comprising: a tubular engaging portion provided on or at the housing for permitting a mating connector to be fitted thereon from front, and a tubular connection section provided on or at the terminal fitting, the tubular connection section being inserted from behind along the inner surface of the tubular engaging portion so as to enable the connection with a mating terminal fitting. Since the lock recess is provided in the rear end position, an area having a high strength stretches over a wide range of the tubular engaging portion from the front end to a middle portion. This enables a secure protection of the tubular connection section. Further, the terminal fitting is allowed to have a sufficient length before the lock recess for the formation of the locking portion. Thus, the reliability of the terminal fitting locking function can be improved by making the locking portion larger. Further preferably, the terminal fitting comprises an outer conductor, an insulating member and an inner conductor, wherein the inner and outer conductors are mounted to each other by means of the insulating member, wherein the engaging portion is a part of the outer conductor. Still further preferably, the inner conductor and the insulating member are at least partially insertable into the outer conductor in the insertion direction. Still further preferably, the outer conductor comprises a wall portion being bendable or positionable in such a position as to intersect the insertion direction. Accordingly, the inner conductor and the insulating member can be securely held in the outer conductor. Most preferably, a portion of the engaging portion on which the lock recess is not provided has a longitudinal length being longer than half the longitudinal length of the terminal fitting. These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawings in which: FIG. 1 is an exploded perspective view of a first embodiment, FIG. 2 is a vertical section of a housing, FIG. 3 is a section along A-A of FIG. 2, FIG. 4 is a plan view of a terminal fitting before an inner conductor is mounted, FIG. 5 is a vertical section of a connector in its assembled state, FIG. 6 is a section along B-B of FIG. 5, and FIG. 7 is a section of a prior art housing. < First Embodiment> Hereafter, a first embodiment of the invention is described with reference to FIGS. 1 to 6. This embodiment is comprised of a housing 10 made e.g. of a resin to be mounted on a circuit board (not shown) and a terminal fitting 20 to be mounted in the housing 10 and connected with the circuit board. The housing 10 is comprised of a tubular engaging portion 11 which has a substantially rectangular cross section and is substantially hollow throughout the length thereof along a longitudinal direction thereof or in forward and backward directions, a receptacle 12 which has a substantially rectangular cross section and projects forward from a position on the outer surface of the engaging portion 11 slightly behind a middle position or portion 11M, and mount portions 13 projecting from the opposite side surface substantially at the rear end of the receptacle 12. The receptacle 12 projects more forward or in a projecting direction PD (FIG. 2) than the engaging portion 11 and is spaced apart from the outer surface of the engaging portion 11 preferably so as to at least partially surround the engaging portion 11. A mating connector (not shown) is fitted or fittable in a mating direction MD between the engaging portion 11 and the receptacle 12 and is lockingly held or holdable by a lock projection 12A formed on the lower surface of the upper wall of the receptacle 12. The mating connector is at least partially fitted or fittable on the engaging portion 11 as described above and the terminal fitting 20 to be described later is at least partially inserted thereinto from an insertion direction ID preferably substantially from behind. At the front end (11F) opening of the engaging portion 11 is formed a stopper 14 for stopping the leading end of the terminal fitting 20 in the longitudinal direction, and the rear end (11R) opening thereof acts as a terminal insertion opening 15. At the rear end of the engaging portion 11 is formed a notch 16 which is open in the lateral or lower surface of the engaging portion 11 so as to substantially communicate with the terminal insertion opening 15. Connection portions 30, 39 of the terminal fitting 20 with the circuit board project downward through the notch 1.6. At the substantially front edge of the notch 16 is formed a receiving projection 17 for receiving the terminal fitting 20 from a lateral side or below. In the inner surfaces of the engaging portion 11 are formed lock recesses 18 as a lock means for locking the terminal fitting 20 substantially in its proper insertion position. The lock recesses 18 are formed at or in the vicinity of or adjacent to the rear end 11R of the engaging portion 11 e.g. by substantially rectangularly thinning the left and right side walls. Locking portions 33 of the terminal fitting 20 are engaged or engageable with stepped or projecting portions 18A left behind the lock recesses 18 from front or in an engagement direction. It should be noted that the lock recesses 18 and the notch 16 therebelow are substantially in flush with each other in particular due to a necessity to detach the molded housing 10 from a mold. The terminal fitting 20 is comprised of a substantially box-shaped outer conductor 21 having an electrical conductivity, an L-shaped inner conductor 22 having an electrical conductivity and an insulating member 23 for assembling or mounting the outer and inner conductors 21, 22 in an insulated manner. The outer conductor 21 is formed e.g. by bending a metal sheet punched into a specified shape by a press and includes a substantially tubular or at least partly laterally open connection section 24 insertable along the inner surface of the tubular engaging portion 11, a rear wall portion 25 for substantially closing the rear end surface of the connection section 24 (when fully mounted or assembled), and leg portions 26 slightly extending downward from the rear end of the connection section 24. The rear wall portion 25 extends substantially in flush with the upper surface of the connection section 24 as shown in FIGS. 1 and 4 before the insulating member 23 is assembled. The rear wall portion 25 is bent at an angle different from 0° or -180° with respect to the connection section 24, preferably substantially downward after the insulating member 23 is substantially accommodated in the connection section 24 so as to substantially hold or position the insulating member 23. The rear wall portion 25 is held bent preferably downward by substantially engaging lock projections 28 formed on locking portion 27 extending from the leading end (bottom end) thereof with lock holes 29 formed in the leg portions 26. On the bottom edges of the left and right leg portions 26 are formed angled or downward extending connection portions 30 to be connected with the circuit board. An elastic locking or restricting portion 31 for restricting a loose backward or longitudinal movement of the assembled insulating member 23 is formed preferably at the rear end of the upper surface of the connection section 24. Further, a pair of elastic contact portions 32 formed e.g. by cutting and bending portions of the side walls of the connection section 24 are provided preferably in front end positions. The elastic contact portions 32 project obliquely preferably forward toward the inside so as to be elastically brought or bringable into contact with an unillustrated mating terminal fitting. On the other hand, a pair of locking portions 33 (locking means) projecting obliquely or at an angle different from 0° or 180° with respect to the connection section 24, substantially backward toward the outside are formed e.g. by cutting and bending portions of the opposite side walls of the connection section 24 in rear end positions or at the end or area opposed to the mating side. These locking portions 33 have their leading ends engaged or engageable with the stepped portions 18A of the lock recesses 18 to restrict a loose backward movement of the terminal fitting 20 with respect to the housing 10. The insulating member 23 has a substantially rectangular shape so as to be at least partially fittable into the rear end of the connection section 24, and a projected portion 34 engageable with the leg portions 26 is formed on the lateral or lower surface of a rear area of the insulating member 23. A mount recess 35 preferably in the form of a slit is formed in the rear surface of the insulating member 23, and a mount hole 36 extending to the front or engaging surface of the insulating member 23 is formed at the back end of the insulating member 23. Further, a receiving stepped portion 37 engageable with the elastic lock portion 31 of the external conductor 21 is formed preferably in the lateral or upper surface of the insulating member 23. A substantially horizontal portion of the inner conductor 22 extending forward or in a direction toward the receptacle 12 (when mounted) acts as a contact portion 38 with the mating terminal fitting and an angled or preferably substantially vertical portion thereof extending at an angle different from 0° or 180° with respect to the contact portion 38, preferably substantially downward acts as a connection portion 39 with the circuit board. The inner conductor 22 and the insulating member 23 are integrally assembled by at least partially inserting the connection portion 38 through the mount recess 35 and pushing it into the mount hole 36. When this assembly is at least partially fitted into the external conductor 21 with the rear wall portion 25 open, the projected portion 34 is engaged with the engaging or rear surfaces of the leg portions 26 and the elastic lock portion 31 is or can be engaged with the receiving stepped portion 37, with the result that the loose movements of the insulating member 23 and the inner conductor 22 with respect to the outer conductor 21 along longitudinal or forward and backward directions are substantially restricted. When the rear wall portion 25 is bent downward in this state, the outer conductor 21, the inner conductor 22 and the insulating member 23 are made into an integral unit, substantially completing the assembling of the terminal fitting 20. The terminal fitting 20 thus assembled is or can be assembled into the housing 10 by at least partially inserting the connection section 24 into the engaging portion 11 preferably from behind (side of the rear end 11R). When the terminal fitting 20 approaches its proper insertion position during the insertion of the terminal fitting 20, the locking portions 33 are brought or bringable substantially into engagement with the inner surfaces of the engaging portion 11, thereby being elastically deformed inward. Thereafter, as the terminal fitting 20 is inserted slightly further, the leading end of the terminal fitting 20 comes into contact with or comes into proximity to the stopper 14, the terminal fitting 20 reaches its proper insertion position and, at the substantially same time, the locking portions 33 are elastically restored to substantially engage the lock recesses 18. The terminal fitting 20 is held so as not to come out preferably by the engagement of the locking portions 33 and the lock recesses 18. With the terminal fitting 20 properly inserted, the leg portions 26 thereof are engaged or engageable with the notch 16 as well as the receiving projection 17. As described above, the engaging portion 11 is formed with the lock recesses 18 as a locking means instead of a long slit as with the prior art locking portion formed in the housing. Further, since the lock recesses 18 are formed by thinning a part of the engaging portion 11 and are not open in the outer surface, a high strength can be ensured for the entire engaging portion 11. This enhances the performance of the engaging portion 11 to protect the terminal fitting 20. The engaging portion 11 is unlikely to be deformed or pried (at its front end 11F and middle portion 11M) even if the mating connector and/or mating terminal fitting is struck against or is obliquely fitted into the engaging portion 11. In this respect, the engaging portion 11 has an excellent performance to retain the terminal fitting 20. Further, since the lock recesses 18 are substantially provided in or at the rear end (11R) positions, an area having a high strength stretches over a wide range from the front end 11F to the middle portion 11M. This also enhances the protecting performance. Preferably, the engaging portion 11 has a longitudinal length LEP from the front end 11F to the middle portion 11M thereof (i.e. where the lock recess 18 is preferably not provided) of at least half the longitudinal length LTF of the terminal fitting 20 or substantially greater than a mating length of the terminal fitting 20 with a mating connector (not shown). Further, by providing the lock recesses 18 in the rear end positions, the terminal fitting 20 is allowed to have a sufficient length before the lock recesses 18 for the formation of the locking portions 33. Thus, the reliability of the terminal fitting locking function can be improved by making the locking portions 33 larger. A sliding resistance between the deformed locking portions 33 and the inner surfaces of the engaging portion 11 during the insertion of the terminal fitting 20 acts in a small region extending from a position where the terminal fitting 20 is considerably inserted to the proper insertion position. Thus; there is little likelihood that operability is reduced due to a sliding resistance. Further, since the locking portions 33 are accommodated in the engaging portion 11, the mating connector is not likely to damage the locking portions 33 when being fitted on the engaging portion 11. <Other Embodiments> The present invention is not limited to the described and illustrated embodiment, but the following embodiments are also embraced by the technical scope of the present invention as defined in the claims. Besides the following embodiments, a variety of other changes can be made without departing from the scope of the invention as defined in the claims. (1) Although the lock recesses are not open in the outer surfaces of the engaging portion in the foregoing embodiment, they may be recessed in the outer surfaces of the engaging portion according to the invention. Accordingly, they may be open in the outer surfaces of the engaging portion. (2) Although the locking means comprised of the locking portion and the lock recess is provided in two positions in the foregoing embodiment, it may be provided in one, three or more positions according to the invention. (3) Although the terminal fitting is comprised of the outer conductor and the inner conductor in the foregoing embodiment, the invention is also applicable to a single-piece terminal fitting having one conductive path. (4) The outer conductor, the insulating member and the inner conductor may be mounted or connected to each other by insert molding. LIST OF REFERENCE NUMERALS 10 Housing 11 Tubular Engaging Portion 18 Lock Recess (Locking Means) 20 Terminal Fitting 24 Tubular Connection Section 33 Locking Portion (Locking Means)

Claims: A connector mountable on a circuit board with a terminal fitting (20) mounted in a housing (10) thereof, comprising: an engaging portion (11) provided on or at the housing (10) for permitting a mating connector to be fitted on a front portion (11F, 11M) thereof from a mating direction (MD), a connection section (24) provided on or at the terminal fitting (20), the connection section (24) being at least partially inserted from an insertion direction (ID) along the substantially inner surface of the engaging portion (11) so as to enable the connection with a mating terminal fitting of the mating connector, and a locking means (18; 33) provided on or at the housing (10) and the terminal fitting (20) for substantially preventing the connection section (24) from being disengaged from the engaging portion (11), wherein the locking means (18; 33) comprises at least one lock recess (18) formed in or on the inner surface of the engaging portion (11) and at least one corresponding locking portion (33) on the connection section (24), which projects obliquely backward from the connection portion (24) and has a leading end engageable with the lock recess (18), wherein the terminal fitting (20) comprises connection portions (30, 39) to be directly connected to the circuit board, characterized in that the lock recess (18) is formed in a rear end (11R) position of the engaging portion (11) when viewed from the mating direction (MD) and the locking portion (33) is disposed at the rear end of the connection section (24) when viewed from the mating direction (MD). A connector according to claim 1, wherein the locking portion (33) is formed by cutting a portion of the connection section (24) and bending a cut portion obliquely backward. A connector according to one or more of the preceding claims, wherein the locking portion (33) is elastically deformable. A connector according to one or more of the preceding claims, wherein the engaging portion (11) is substantially tubular and/or wherein the connection section (24) is substantially tubular. A connector according to one or more of the preceding claims, wherein the terminal fitting (20) comprises an outer conductor (21), an insulating member (23) and an inner conductor (22), wherein the inner and outer conductors (22, 21) are mounted to each other by means of the insulating member (23), and wherein the connection section (24) is a part of the outer conductor (21). A connector according to claim 5, wherein the inner conductor (22) and the insulating member (23) are at least partially insertable into the outer conductor (21) in the insertion direction (ID). A connector according to claim 6, wherein the outer conductor (21) comprises a wall portion (25) being bendable or positionable in such a position as to intersect the insertion direction (ID). A connector according to one or more of the preceding claims, wherein a portion (11F; 11M) of the engaging portion (11) on which the lock recess (18) is not provided has a longitudinal length (LEP) being longer than half the longitudinal length (LTF) of the terminal fitting (20).

Inventors: KOIDE TAKASHI, KOIDE, TAKASHI
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1999
Main classification: H01R13
IPC codes: H01R13