Abstract:
A plug-in connecting structure where a first unit, on an outer surface of which a first connector housing is installed, and a second unit, on an outer surface of which a second connector housing is installed, are connected electrically with each other by connecting the connector housings with each other, simultaneously with the mechanical connection of the units with a certain support being as a guide. When advancing toward a connecting portion of the second connector housing, a connecting portion of the first unit automatically aligns its center axis with a center axis of the connecting portion of the second connector housing, with being guided by a tapered surface. The first and second connector housings are never forcibly connected with each center axis thereof remaining offset from each other.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a plug-in connection structure wherein a pair of predetermined units are electrically connected with each other simultaneously with mechanical connection thereof. 
     2. Description of the Related Art 
     For example, a plug-in connection structure is employed for electrically connecting a roll connector, fixed to a steering column, with a steering wheel which is to be attached to the steering column. Generally, in a plug-in connection structure, when a unit and another unit are connected with each other with a predetermined support being as a guide, connector housings arranged on the outer surface of each unit are connected with each other with the connection of the units, so that the mechanical and electrical connection of the units are simultaneously realized. In the above example, “a predetermined support”corresponds to the steering column, and “a unit” and “another unit” correspond to the steering wheel and the roll connector, respectively. 
     In such a plug-in connection structure, relative position of two units as a whole is restricted by a support serving as a guide, and on the outer surface of the units there are fixed first and second connector housings which are to be connected with each other in a male and female connecting manner. The first and second connector housings fixed thereon in such a way are connected with each other simultaneously with the mechanical connection of the units. Therefore, it is necessary to precisely arrange each connector housing at a predetermined position on the outer surface of each unit. In case that this precision is inferior, since the offset connector housings are forcibly connected, some stress is applied on a contact terminal, thus causing insufficient contact due to deflection or deformation of the terminal. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to provide a plug-in connection structure wherein even if each connector housing, arranged on each of outer surfaces of units which are to be connected with each other, is swerved or dislocated from a predetermined position thereon, suitable connection of the connector housings can be realized. 
     In order to achieve the object of the present invention, there is provided a plug-in connection structure wherein a first unit, on an outer surface of which a first connector housing is provided, and a second unit, on an outer surface of which a second connector housing is provided, are connected electrically with each other by connecting the first connector housing and the second connector housing with each other, simultaneously with mechanical connection of the first unit and second unit with each other with a predetermined support being as a guide. The first connector housing has a first base provided on the outer surface of the first unit, and has a first connecting portion which is projected from the first base and which is connected to the first base so as to slide along the outer surface of the first unit relatively to the first base. The second connector housing has a second base provided on the outer surface of the second unit, and has a second connecting portion surrounded by a peripheral wall which is projected from the second base and which has a tapered inner surface widening towards a free edge of the peripheral wall. One of the first base and the second base is detachably attached to the outer surface. A retracting pin is fixed to the first connector housing. A retracting lever is pivotably mounted on the peripheral wall of the second connector housing. The retracting lever engages with the retracting pin and can pivot toward the second unit to pull the first connector housing toward the second unit so that the first connecting portion and the second connecting portion are connected with each other. 
     In the plug-in connection structure of the present invention as above, when the first and second units are made approach to each other to be connected, firstly, the first connecting portion of the first connector housing is located inside the tapered peripheral wall of the second connector housing. As the first and second units further approach each other, the tapered inner surface of the peripheral wall becomes narrower, and at the narrowest location thereof there exists the second connecting portion of the second connector housing. On the other hand, the first connecting portion of the first connector housing can slide along the surface of the first unit. Thanks to this, when advancing toward the second connecting portion of the second connector housing, the first connecting portion of the first connector housing automatically aligns its center axis with the center axis of the second connecting portion of the second connector housing, and is guided by the tapered surface. 
     Further, since the retracting lever pivotally mounted on the peripheral wall is engaged with the retracting pin which is fixed to the first connector housing, when the retracting lever is pivoted toward the second unit finally, one of the first and second connector housing is released from the associated unit surface, so that the connection of the first and second connector housings is completed. That is, the first and second connector housings are never forcibly connected with each center axis thereof remaining offset. 
     In the plug-in connection structure of the present invention, the first connecting portion of the first connector housing may comprise a body having a cross-shaped cross section. The first connecting portion of the first connector housing may slide in a normal direction relatively to a connecting direction of the first unit and the second unit. 
     The plug-in connection structure of the present invention may further comprise a holding means to hold the retracting lever at a retracting position at which the retracting lever is positioned on a side of the second unit. The holding means preferably comprises a holding hook projected from the second base, and a tip part of the retracting lever in which the holding hook and the tip part can engage with each other. 
     The plug-in connection structure of the present invention may further comprise a fixing means to temporally fix a relative position of the first connecting portion and the first base. The fixing means preferably comprise a holding protrusion provided on the first base, and a holding portion extending from the first connecting portion nearly to a surface of the first base so as to be able to elastically engage with the holding protrusion. 
     In the above description, the first connecting portion projecting from the first base of the first connector housing is made to be able to slide relatively to the first base. Alternatively, the second connecting portion of the second connector housing surrounded by the peripheral wall can be made to be able to slide with the peripheral wall relatively to the second base. With this alternation, the same benefit is also brought. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This and other objects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, in which: 
     FIG. 1 is an explanatory view showing two units, before the connection, which are to be connected with each other with a plug-in connection structure of the present invention; 
     FIG. 2 is a partial perspective view of the first and second connector housings shown in FIG. 1; 
     FIG. 3 is a partially broken cross sectional view of the second connector housing shown in FIG. 1; 
     FIG. 4 is an explanatory view showing the retracting lever pivotally mounted on the second connector housing shown in FIG. 1, in which the retracting lever is in a receiving position; 
     FIG. 5 is an explanatory view showing the retracting lever having been pivoted to a retracting position from the receiving position in FIG. 4; 
     FIG. 6 is a side elevation of the first connector housing shown in FIG.  1 . 
     FIG. 7 is an explanatory view showing two units, before the connection, which are to be connected with each other with a plug-in connection structure of the present invention; and 
     FIG. 8 is a partially broken cross sectional view of the second connector housing shown in FIG.  7 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the present invention is described below in detail with reference to the accompanying drawings. FIG. 1 shows main portions of a first unit  100  and a second unit  200  before connection, in a state wherein they are close to each other. FIG. 2 is a perspective view which shows a first connector housing  110  fixed to the first unit  100  and a second connector housing  210  fixed to the second unit  200 . In the present invention, the first unit  100  and the second unit  200  are not limited to particular ones. For example, the present invention is applied to a case wherein the first unit  100  is a steering wheel, and the second unit  200  is a roll connector which is to be connected to the steering wheel mechanically and electrically. 
     As shown in FIG. 2, the first connector housing  110  comprises a base (first base)  160  shaped like a rectangular frame, and a connecting portion (first connecting portion)  130  which is projected from the base  160  and encloses, or accommodates, contact terminals. The base  160  is detachably fixed to a recess  101  formed on the outer surface of the first unit  100 . That is, as shown in FIG. 1, on the two opposed side members of the frame-like base  160 , there are arranged holding protrusions  161 , and on the corresponding side walls of the recess  101 , there are also arranged holding protrusion  102 . Thus, the base  160  is normally held in the recess  101 . But under a pulling force, the elastic engagement of the holding protrusions  161  and  102  is released, or detached, so that the base  160  is released from the recess  101 ; in other words, the first connector housing  110  is released from the recess  101 . Although not shown in FIG. 1, electric wires  105  are running from the first connector housing  110  into the first unit  100  (FIG.  2 ). 
     The connecting portion  130  is mounted to the base  160  so as to slide along the base surface. Thus, when the first connector housing  110  is fixed on the first unit  100 , the connecting portion  130  can slide along the surface of the first unit  100 . The connecting portion  130  comprises a body  131  having a cross-shaped cross section and enclosing contact terminals, and four sliding legs  132  fixed to an end of the body  130  so as to extend in normal direction to the body  130 . Each sliding leg is an elongated plate-like member, and they all exist in one plane. There are two pairs of sliding legs, each pair thereof comprising two sliding legs extending in parallel; thus there are four sliding legs in total. Two pairs of the extending legs are extending in opposite direction. As to the sliding legs, alternatively, there can be employed four legs extending in cross-shape, other than that shown in FIG.  2 . Of course, in that case, the constitutions of the base  160  and the recess  101  of the first unit  100  are accordingly modified. 
     On the other hand, at each of two opposed side members of the rectangular frame-like base  160 , an elongated guide slot  165  is formed respectively. Into these guide slots  165 , the sliding legs  132  are slidably inserted. Thus, as can be understood from FIG. 2, the connecting portion  130  can freely slide relatively to the base  160  along the surface thereof. From one wall surface of the connecting portion  130 , there is projected a retracting pin  135  which is utilized at the time of retracting (pulling) the first connector housing  110  into the second connector housing  210 . The function of this retracting pin  135  will be described below. 
     The second connector housing  210  comprises a base (second base)  260  which is fixed to the second unit  200 , and a connecting portion (second connecting portion)  235  surrounded by a peripheral wall  230  projected from the base  260 . In FIG. 2, the peripheral wall  230  is solo shown with a retracting lever  240  pivotably mounted thereon. FIG. 3 is a side elevation partially broken away to explain the constitution of the second connector housing  210 . In FIG. 3, showing the retracting lever  240  is omitted. 
     The peripheral wall  230  is surrounding the connecting portion  235  of the second connector housing  210 , and the inner surface  231  thereof is tapered so as to widen towards a free edge of the peripheral wall  230 . The connecting portion  235  is located at the narrowest position inside the peripheral wall  230 . The connecting portion  235  comprises a plurality of contact terminals  236 . Each contact terminal  236  is inserted into an connection opening  131   a  formed at the front face of the connecting portion body  131 , and connected to the contact terminal (not shown) enclosed in the first connector housing  110 . On one wall portion of the peripheral wall  230  there is formed a straight retracting guide inlet  232 , and on the base  260  there is projected a holding hook  261 . The functions of these guide inlet  232  and holding hook  261  will be described below. 
     As shown in FIGS. 1 and 2, on the peripheral wall  230 , there is pivotaly mounted the retracting lever  240 . The retracting lever  240  is constituted by connecting two side walls  242  and  244 , extending in parallel, with a connecting plate  243 . The retracting lever  240  can pivot about a center shaft  241  between a receiving position shown in FIG. 1 and a retracting position shown in FIG.  5 . The retracting lever  240  is held at the receiving position by a holding protrusion  233 , and is held at the retracting position by the holding hook  261 . On one side-plate, there is formed a curved retracting inlet  245 . The function of this retracting inlet  245  will be described below. 
     The actual connecting procedure of the plug-in connection structure of the embodiment is described hereinafter. In FIG. 2, showing each unit is omitted, and the first connector housing  110  and the second connector housing  210  are shown. Firstly, the first and second units  100  and  200 , on which the respective connector housings are mounted, are made approach to each other (FIG.  1 ). Then, as shown by an arrow in FIG. 2, the retracting pin  135  is made pass below a bridge  246  into the inlet  245  of the retracting lever  240 . Now, the connecting portion  130  projected from the first connector housing  110  is placed inside the tapered peripheral wall  230 . 
     From this condition, the first and second units  100  and  200  are forced toward to each other, so that the connection openings  131   a  of the first connector housing  110  and the contact terminals  236  of the second connector housing  210  are positioned face to face in alignment (namely, without relative positional offset). This condition is shown in FIG.  4 . As described above, the connecting portion  130  can freely slide along the surface of the base  160  fixed on the first unit  100 , that is, along the surface of the first unit  100 . Accordingly, even if there is some offset between the location of the first connector housing  110  on the first unit  100  and the location of the second connector housing  210  on the second unit  200 , the connecting portion  130  slides along the surface of the first unit  100  while being guided by the tapered inner surface  231  of the peripheral wall  230 . The connecting portion  130  advances toward the connecting portion  235  of the second connector housing  210 , and the connection openings  131   a  of the first connector housing  110  and the contact terminals  236  of the second connector housing  210  are brought face to face in alignment (namely, without relative positional offset). 
     In the condition of FIG. 4, respective positions of the first and second units  100  and  200  are fixed on a predetermined support, and the both units do not approach to each other any more. For example, in the case of the steering wheel and the roll connector as described above, the respective positions of them are fixed to that shown in FIG. 4 on the steering column as a support, so that the relative position of them are restricted. In FIG. 4, the retracting lever  240  is shown in a position slightly pivoted from the receiving position in FIG. 1 toward the second unit  200 . 
     From the condition of FIG. 4, when the retracting lever  240  is pivoted in direction of an arrow “A”, the retracting pin  135  located in the retracting inlet  245  of the lever  240  is retracted or pulled into the peripheral wall  230  of the second connector housing  210  by the pivoting movement of the lever  240 . Simultaneously with this, the base  160  of the first connector housing  110  is released or detached from the first unit  100 . It is to be noted that the electrical connection between the first connector housing  110  and the first unit  100  is of course kept. 
     When the retracting pin  135  is retracted by the retracting lever  240 , the pin  135  advances straight toward the second unit  200  in the retracting guide inlet  232  which is formed straight on the peripheral wall  230  of the second connector housing  210 . Then, the contact terminals  236  of the second connector housing  210  are inserted into the connection openings  131   a  of the first connector housing  110 , so that the electrical connecting of the first unit  100  and second unit  200  is completed. This condition is shown in FIG.  5 . It is convenient to pivot the retracting lever  240  by manipulating the connecting plate  243  with fingers. In FIG. 5, one edge of the connecting plate  243  is engaged with a holding protrusion  262  at the tip of the holding hook  261 , so that the retracting lever  240  is held in that position. 
     The releasing procedure of the two units  100  and  200  which have been connected electrically and mechanically as above is vice versa. Its brief explanation is as follows. The retracting lever  240  of the second connector housing  210  is pivoted from the retracting position in FIG. 5 to the receiving position in FIG. 4, and the first connector housing  110  is again engaged with the first unit  100  at the base  160  thereof. Then, the retracting pin  135  of the first connector housing  110  is passed below the bridge  246  so as to be released from the retracting inlets  232  and  245 . A sloped surface  136   a  is partially formed on the head  136  of the retracting pin  135 , so the retracting pin  135  can easily pass below the bridge  246  (FIG.  6 ). 
     FIG. 6 shows a side elevation of the first connector housing  110 . From the edge, facing the base  160 , of the connecting portion body  131 , there is formed a holding portion  234  extending nearly to the surface of the base  160 . This holding portion  234  is elastically engaged with a holding protrusion  166  on the base  160  to temporarily fix the relative position of the connecting portion  130  to the base  160 . From FIG. 6, it can be understood that the holding protrusion  166  of the base  160  is engaged in a recess  234   a  at the edge of the holding portion  234 . 
     In the shown embodiment, the base  160  and the connecting portion  130  of the first connector housing  110  slide relatively toward to each other, and the peripheral wall  230  surrounding the connecting portion  235  and the base  260  of the second connector housing  210  are integratedly formed so as not to slide to each other. In the present invention, however, an opposed construction can be employed. That is, the base  160  and the connecting portion  130  of the first connector housing  110  can be integratedly formed so as not toward slide to each other, and the peripheral wall  230  surrounding the connecting portion  235  and the base  260  of the second connector housing  210  can relatively slide toward each other. With such the opposed construction, the same benefit is also realized. 
     Further, when pivoting the retracting lever  240  to connect the first and second connector housings  110  and  210 , the second connector housing  210  rather than the first connector housing  110  can be released from the associated unit. As seen in FIG. 7, a recess  101 ′ is provided near an outer surface of the second unit  200 . This second embodiment including corresponding protrusions  102 ′,  161 ′. FIG. 8 shows how the second peripheral wall  230  can slide relatively toward the second base  260  as opposed to the relative movement of components  130  and  160  in the first embodiment. Two positions  260  and  260 ′ are shown to demonstrate the change in relative positions. 
     Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.