Abstract:
A connector comprises: a plurality of male housings each having terminal receiving chambers for receiving and retaining a female terminal; a female housing in which the male housings are fittingly received; a lock lever pivotally provided to the female housing, the lock lever being closed only when each of the male housing is completely lockingly fitted in the female housing; a first locking member provided to each of the male housings and the female housing for locking each other; a second locking member provided to each of the male housings and the lock lever for locking each of the male housings and the female housing each other; and electrical detecting member whether each of the male housings and the female housing are completely fitted and locked to each other or not.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an improved switch terminal and an improved connector with such a switch terminal. 
     Generally, with respect to a connector used for interconnecting wire harnesses, a pair of female and male housings are fitted together so as to connect metal terminals, received in these housings, together. In order to maintain electrical connection between these metal terminals, a lock member is provided between the two housings to prevent them from being disengaged from each other. In order to detect the fitted and locked condition of the two housings not by a lock sound or a visual inspection but by electrical means, there has been proposed a method in which a switch terminal is received in one of the two housings, and is adapted to be closed upon complete fitting between the housings. 
     FIG. 12 shows one example of such switch terminal (Japanese unexamined Utility Model Application No. 55-51731) in which a pair of main contact pieces d and d, which are urged by springs c and are short-circuited together by a short-circuit piece b before a test plug (not shown) is inserted into an insulating casing a from an opening a1 thereof, and a pair of auxiliary contact pieces e and e, which are contacted with the test piece before the main contact pieces d, are provided on inner surfaces of the casing a. 
     FIG. 13 shows another conventional example in which a switch mechanism is constituted by a fork-like contact piece f, having contact portions f1 and f1 of a bifurcated configuration, and a spring contact piece g having contact portions g1 and g1 of a saddle-like configuration for contacting with the contact portions f1 and f1 of a bifurcated configuration. The two contact pieces f and g are disposed at respective positions offset from the center of an insulating housing h in opposed relation to each other, and a central hole i is formed through a central portion of a front end of the insulating housing h, and a plug terminal (not shown) is passed through the central hole i to be engaged with the saddle-like contact portions g1 and g1 of the spring contact piece c so as to open and close the above switch mechanism. 
     In the above conventional switch terminals, the springs are used to apply a contact load to the contact portions (FIG. 12), and the fork-like contact piece and saddle-like spring contact piece of different shapes are used (FIGS. 13a and 13b). Therefore, the number of the component parts is large, and the constructions are complicated, and much time is required for the assembling, thus posing a problem that the operability is worse. 
     SUMMARY OF THE INVENTION 
     The present invention was made in order to solve the problems mentioned above. Accordingly, it is an object of this invention to provide a switch terminal which can be easily attached to a connector housing in a short time, and also to provide a connector in which whether or not the fitting condition is proper can be electrically detected using such a switch terminal. 
     In order to achieve the above object, according to the present invention, there is provided a switch terminal including a pair of connecting pieces each having a base plate portion which has a terminal portion at one end thereof and a spring contact portion at the other end thereof, the base plate portions of the two connecting pieces being interconnected in parallel relation to each other by a connective portion, each of spring contact portions being bent into an arcuate configuration from an outer side edge of the base plate portion toward an inner side edge thereof to provide a folded portion, and distal ends of the folded portions being capable of contacting each other to thereby provide a normally-closed contact. 
     According to another aspect of the invention, there is provided a connector with a switch terminal, comprising a switch terminal, and a connector housing having a switch terminal receiving chamber; the switch terminal including a pair of connecting pieces each having a base plate portion which has a terminal portion at one end thereof and a spring contact portion at the other end thereof, the base plate portions of the two connecting pieces being interconnected in parallel relation to each other by a connective portion, each of the spring contact portions being bent into an arcuate configuration from an outer side edge of the base plate portion toward an inner side edge thereof to provide a folded portion, and distal ends of the folded portions being capable of contacting each other to thereby provide a normally-closed contact; the switch terminal receiving chamber having at its wall surface a partition rib for isolating the pair of connecting pieces of the switch terminal from each other; guide walls which converge forwardly in a tapered manner being formed respectively on opposite side walls of the switch terminal receiving chamber at a terminal inlet portion thereof, the partition rib being disposed between the opposite side walls; upon insertion of the switch terminal into the switch terminal receiving chamber, a pair of spring contact portions are urged by the tapered guide walls, so that the ends of folded portions are contacted with each other to form the normally-closed contact; and a pair of connecting pieces being insulatively separated from each other by cutting off said connective portion. 
     In this connector with the switch terminal, there is provided a pivotal lock lever which is closed when a mating connector housing is completely lockingly fitted in the connector housing receiving the switch terminal, the lock lever having an insulating projection which can intrude between the ends of a pair of folded portions forming the normally-closed contact of the switch terminal, thereby breaking the normally-closed contact. With this arrangement, whether the fitting between the pair of connector housings is good or not can be electrically judged. 
     The switch terminal of the present invention is of a simple construction in which the pair of connecting pieces each having the terminal portion at one end thereof and the spring contact portion at the other end thereof are connected together by the connective portion. Thus, the switch terminal is provided as one component part, and therefore the number of component parts is greatly reduced as compared with the conventional constructions. 
     In order to form the connector with the switch terminal by the use of the switch terminal, the switch terminal is inserted into the switch receiving chamber, and the pair of spring contact portions are urged by the tapered guide walls, so that the ends of the folded portions are contacted with each other to form the normally-closed contact. At the same time, the connective portion is cut off to insulatively separate the pair of connecting pieces from each other. Thus, the assembling operation can be carried out easily in a short time. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view showing a switch terminal and a connector, provided in accordance with the present invention; 
     FIGS. 2a and 2b are an enlarged perspective view and a front-elevational view of the switch terminal, respectively; 
     FIG. 3 is a front-elevational view of a female housing A; 
     FIG. 4 is an enlarged front-elevational view of a switch receiving chamber of the female housing A; 
     FIG. 5 is a cross-sectional view taken along the line V--V of FIG. 4; 
     FIG. 6 is an enlarged front-elevational view of the switch receiving chamber into which the switch terminal C is inserted; 
     FIG. 7 is a cross-sectional view taken along the line VII--VII of FIG. 6; 
     FIG. 8 is a perspective view of an important portion, showing the condition of insertion of the switch terminal C into the switch receiving chamber; 
     FIG. 9 is a perspective view showing the female housing A of FIG. 1 and a lock lever 14 separated therefrom; 
     FIGS. 10a and 10b are fragmentary cross-sectional views showing the process of fitting of a male housing B1 into the female housing A of FIG. 1; 
     FIGS. 11a and 11b are fragmentary cross-sectional views showing the operations of the switch terminal C of FIG. 1 and the lock lever 14; 
     FIG. 12 is a cross-sectional view of a conventional switch terminal; and 
     FIGS. 13a and 13b are a perspective view of a switch mechanism of a conventional coaxial connector with a switch and a cross-sectional view of this connector, respectively. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1, reference character A denotes a female housing of a synthetic resin, reference characters B1, B2 and B3 male housings, and reference character C a switch terminal. The female housing A is of a complex type, and is connected directly on a printed circuit board 11. 
     A plurality of juxtaposed terminal receiving chambers 1 are provided within the male housings B1, B2 and B3 (hereinafter represented by B1), and a female terminal 2 is received and retained in each of these chambers. A locking arm 3 with a retaining projection 3a for the female housing A, as well as a fitting confirmation projection 4, is formed on the outer surface of the male housing. 
     The male housing A has a hood 5 formed at its front half portion, and as shown in FIG. 3, a plurality of juxtaposed tab insertion holes 9 are provided at the rear half portion thereof. L-shaped terminals 10 are press-fitted in the holes 9, respectively, and are connected to circuit conductors (not shown) of the printed circuit board 11 by soldering or the like. 
     The hood 5 has a plurality of partition walls 6 therein which divide the interior thereof into fitting chambers 5 1 , 5 2  and 5 3  for respectively receiving the male housings B1, B2 and B3. A slit 7 for receiving the fitting confirmation projection 4 of the male housing B, a slit 7&#39; for an insulating projection 14d of a lock lever 14 (later described), and a retaining portion 8 (see FIG. 10) for engagement with the retaining projection 3a of the locking arm 3 are provided in each fitting chamber. 
     As shown on an enlarged scale in FIGS. 2a and 2b, the switch terminal C has a pair of parallel connecting pieces 12 and 12&#39; connected together. The connecting piece 12 (12&#39;) has a base plate portion 12a having a terminal portion 12b formed at one end thereof, and a spring contact portion 12c (12c&#39;) is formed at the other end of the base plate portion 12a. The base plate portions 12a and 12a are interconnected by connective portions 12d and 12d&#39; intermediate the opposite ends thereof. The spring contact portion 12c (12c&#39;) has an inclined side wall 12c1 extending from the outer side edge thereof away from the other spring contact portion, and the free end portion of the inclined side wall 12c1 is folded back inwardly into an arcuate shape to provide a folded portion. Distal ends 12c2 and 12c2 of the folded portions of the spring contact portions are normally contacted with each other to provide a normally-closing contact. A retaining piece 12e and a fixing piece 12f for bending purpose are formed on the outer side edge of the base plate portion 12a of each connecting piece 12 (12&#39;), and are arranged in this order from the spring contact portion 12c. In this embodiment, although the terminal portion 12b of the connecting piece 12 serves as a connection pin directly connected to the printed circuit board 11, it may be formed as an ordinary tab-like male terminal or a corresponding female terminal. 
     As shown in FIG. 3, in addition to the tab insertion holes 9 for the L-shaped terminals 10, a switch terminal receiving chamber 13 is provided in the fitting chamber 5 1  of the female housing A. 
     As shown on an enlarged scale in FIGS. 4 and 5, in the switch terminal receiving chamber 13, a partition rib 13a, extending in the axial direction of the switch terminal C, and a transverse rib 13b intersecting the partition rib are formed on a bottom wall, and opposed side walls are tapered at a terminal inlet portion toward the front side to provide tapered guide walls 13c and 13c. An insertion hole 13d for the connecting piece 12 (12&#39;) of the terminal C and slits 13e and 13e for the retaining pieces 12e are formed in those walls disposed deeper than the tapered guide walls (see FIG. 4). 
     The switch terminal C is inserted into and attached to the switch terminal receiving chamber 13 in the following manner. 
     As shown in FIGS. 6 to 8, the switch terminal C is inserted into the switch terminal receiving chamber 13, so that the terminal portions 12b of the pair of connecting pieces 12 and 12&#39; are passed through the insertion hole 13d and are projected forwardly. When the insertion further proceeds, the pair of spring contact portions 12c and 12c&#39; advances in such a manner that their inclined side walls 12c1 are urged toward each other by the tapered guide walls 13c and 13c. When the retaining pieces 12e are engaged with the slits 13e, the insertion is stopped, and the ends 12c2 and 12c2 of the pair of spring contact portions 12c and 12c&#39; are resiliently held in intimate contact with each other to thereby form a normally-closed contact. At this time, the connecting pieces 12c and 12c&#39; are isolated from each other by the partition rib 13a, and each base plate portion 12a is seated on the inner portion of the transverse rib 13b. In this condition, the connective portions 12d and 12d&#39; are cut off, and at the same time fixing pieces 12f and 12f are bent toward each other, thereby preventing the withdrawal of the switch terminal in front and rear directions, as shown in FIG. 8. 
     Referring again to FIG. 1, the lock lever 14, having a lock spring 15 mounted thereon, is pivotally connected at its one end to the rear portion of the hood portion 5 of the female housing A, and two lock plates 16 and 16 for holding the lever 14 in a provisionally-locked condition and in a completely-locked condition are formed on the front portion of the female housing A. 
     The lock lever 14 has a plate-like configuration, and has an operating press portion 14a provided at the central portion of the front edge portion thereof, and a screen portion 14b extending upwardly from the press portion 14a. As shown in FIG. 9, fitting confirmation projections 14c for interfering respectively with the projections 4 of the male housings B1 to B3, as well as an insulating projection 14d for breaking the normally-closed contact of the switch terminal C, are formed on the reverse surface of the lock lever 14. The lock lever 14 has engagement holes 14e formed respectively in its opposite side portions at its rear edge portion, and these holes 14e are engaged respectively with C-shaped hooks 5a, formed at the rear end of the hood 5, so that the lock lever 14 is pivotally connected to the hood 5. 
     The lock plates 16 and 16 have a frame-like configuration, and a provisionally-locking groove 16b and a completely-locking groove 16c for engagement with the lock spring 15 are formed in each of opposed side walls 16a of the lock plates 16, the groove 16b being disposed above the groove 16c, as shown in FIG. 11. The completely-locking groove 16c is deeper than the provisionally-locking groove 16b. 
     In the above construction, when the male housing B1 (B2, B3) is inserted into the fitting chamber 5 1  of the female housing A, the locking arm 3 is flexed downward as shown in FIG. 10a, and when the complete fitting is achieved, the arm 3 is restored into its initial form, so that the retaining projection 3a is engaged with the retaining portion 8 to achieve a first-stage lock as shown in FIG. 10b. 
     When the fitting is to be effected, the projection 4 of the male housing B1 enters the fitting chamber 5 1  through the introduction slit 7 (see FIGS. 1 and 9); however, in the half-fitted condition shown in FIG. 10a, the projection 14c of the lock lever 14 interferes with the projection 4, and therefore the lever 14 can not be closed (that is, the complete locking later described can be made). In the completely-locked condition shown in FIG. 10b, the projection 14c of the lock lever 14 is disposed rearwardly of the projection 4, and therefore can enter the interior through the slit 7, so that the lever 14 can be closed. With the engagement between the projection 14c and the projection 4, the male housing B1 is locked relative to the female housing A (i.e., the fitting chamber 5 1 ) in a double manner. With this arrangement, the electrical connection between the group of female terminals 2 and the group of L-shaped terminals 10 is achieved at the same time. 
     Thus, if any one of the male housings B1, B2 and B3 is in a half-fitted condition, the lock lever 14 can not be closed, and the closing of this lever 14 means that every male housing has been mechanically locked in a double manner. 
     The switch terminal C electrically detects the above mechanical double lock. 
     FIGS. 11a and 11b shows the operations of the switch terminal C and the lock lever 14, and for the sake of simplicity of the illustration, the male housings B1, B2 and B3 are omitted from these Figures. 
     In FIG. 11a, the lock lever 14 is inclined relative to the hood 5 and is held in the provisionally-locked condition, with the lock spring 15 engaged in the provisionally-locking grooves 16b of the lock plates 16. As shown in FIG. 10a, in this provisionally-locked condition, the male housing Bl can be freely fitted and removed. The insulating projection 14d on the lower surface of the lock lever 14 is projected into the switch terminal receiving chamber 13 through the slit 7&#39; (see FIG. 9), and is disposed between the spring contact portions 12c and 12c&#39; of the switch terminal C, but the ends 12c2 and 12c2 of the folded portions are held in contact with each other. 
     In FIG. 11b, all of the male housings B1 to B3 are in the completely-fitted condition, and the lock lever 14 is in the completely-locked condition. Namely, the lock lever 14 is pressed down from the condition shown in FIG. 11a, so that the lock spring 15 is lockingly engaged with the completely-locking grooves 16c, and at the same time the insulating projection 14d intrudes between the ends 12c2 and 12c2 of the folded portions of the spring contact portions 12c and 12c&#39; to interrupt the two connecting pieces 12 and 12&#39; from each other. 
     The connecting pieces 12 and 12&#39; are connected to an alarm circuit (not shown) via the printed circuit board 11, and a display, such as the turning-on and -off of an alarm lamp, is adapted to be made. With this arrangement, the complete fitting between the female and male housings A and B1 (B2, B3), as well as the double lock thereof, can be electrically confirmed, thereby ensuring the safety of the circuit. 
     As described above, in the present invention, the switch terminal, before inserted into the female housing, is provided as one component part, and therefore the number of the component parts can be reduced, and the attachment of the switch terminal to the housing can be effected efficiently. 
     Further, this switch terminal is used in combination with the lock lever which effects the double lock of the female and male housings, and with this arrangement the half-fitting of the connector is prevented, and there can be provided the electric connector extremely enhanced in electrical connection.