Abstract:
A lever-type electrical connector has first and second connector housings adapted to be detachably fitted together in a connected position by relative movement in a fitting direction. A lever is rotatably mounted for drawing the connector housings towards said connected position. Locking means are provided on the connector housings for locking them together in the connected position. Springs act operatively between the connector housings to be compressed when the connector housings are being moved towards the connected position, thereby to create a force urging the connector housings in their separation direction at least during the movement of the connector housings towards the connected position. This reduces the risk of incomplete fitting together of the housings.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a lever-type electrical connector, for example a connector suitable for use in a motor vehicle to connect wire bundles. 
     2. Description of the Related Art 
     It is necessary to connect multipolar electrical connector components to each other with a high fitting force. For this purpose a lever-type connector is employed. In a lever-type connector, for example, a lever having a cam groove is rotatably mounted on a male housing, and a follower fitting in the cam groove is provided on a mating female housing. When the two housings are fitted to each other, with the lever at an initial position, the follower enters the entrance of the cam groove. With rotation of the lever, the housings are drawn together, as the follower moving in the cam groove. The construction is intended to permit fitting of the housings to each other with a small applied force, utilizing the action of the lever. This type of lever-type connector is disclosed in JP-A-6-275337. A similar connector is disclosed in U.S. Pat. No. 5,476,390. 
     In the above-described lever-type connector, when the lever has rotated to its rotational termination, the two housings are normally fully fitted in each other. As the lever approaches its rotational termination, the fitting resistance becomes large, while the applied force remains low. Thus, there is a danger that the lever-rotating operation is stopped before the housings are fully fitted to each other. As a result, the housings are left in an incompletely fitted state. Further, even if the lever is rotated to its rotational termination, the housings may be left in an incompletely fitted state owing to an error in the manufacture of component parts of the housings. In either case, it may be very difficult for the operator to detect such incomplete fitting. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a lever-type connector permitting detection of whether the two connector housings have been normally fitted in each other. 
     With a view to achieving this object, according to the invention there is provided a lever-type electrical connector having first and second connector housings adapted to be detachably fitted together in a connected position by relative movement in a fitting direction, and a lever rotatably mounted on the connector for drawing the connector housings in said fitting direction towards said connected position. Locking means are provided on the connector housings for locking them together in the connected position. Spring means are provided to act operatively between the connector housings so as to be resiliently deformed when the connector housings are being moved towards the connected position, thereby to create a force urging the connector housings in their separation direction at least during the movement of the connector housings towards the connected position. 
     In this construction, to fit the two connector housings to each other, the lever is rotated. When the connector housings have achieved a normal connected or fitted state, the locking means holds the fitted state. If the fitting operation is stopped before the connector housings are in the normal fitted state, the urging force of the spring means causes the connector housings to separate from each other. Irrespective of the position of the lever therefore, it is possible to securely detect whether or not the connector housings have been fitted in each other normally. 
     Preferably the spring means comprises at least one spring having a front end and a rear end, the first connector housing acting upon the front end of the spring to compress it during fitting of the connector housings together, and the second connector housing has a spring holder restraining the rear end of the spring. In this embodiment, the spring holder is arranged to cooperate with the locking means so that, during fitting of the connector housings together, (i) before the locking means locks the connector housings in the connected position the spring holder restrains the spring from relaxation of its compressed state, and (ii) when the locking means has locked the connector housings in the connected position the locking means releases the restraint of the spring to allow at least partial relaxation of the spring. In this embodiment, when the connector housings are fitted to each other, the spring incorporated in the second connector housing is acted on by the first connector housing. At this time, the spring holder restrains the rear end of the spring. Thus, with the progress of the fitting operation, the spring is gradually compressed. Accordingly, if the fitting operation is stopped before the connector housings are fitted on each other normally, they are separated from each other by the spring force. The spring force is relaxed on normal fitting, and this may be detectable by the user. 
     Preferably the locking means comprises cooperating members in the form of at least one locking projection provided on the first connector housing and correspondingly at least one resiliently deformable locking arm provided on the second connector housing. The locking projection and locking arm are arranged and shaped so that, when the connector housings are moved towards the connected position, the locking arm engages and is deflected by the locking projection and thereafter locks behind the locking projection in a latch manner. The locking arm when so deflected prevents the spring holder releasing the compressed state of the spring. With the progress of the fit-in operation, the locking arm rides on the locking projection. When the housings have been fitted in each other, the locking arm returns to its original state by its elastic or resilient deformation and is locked to the locking projection. As a result, the connector housings are prevented from separating from each other. In association with this restoring operation of the locking arm, the spring holder releases the rear end of the spring. Thus, the spring is released from the compressed state. Accordingly, after the connector housings are fitted in each other normally, the spring force does not act as a connector separating force. 
     When the connector housings are long and narrow, there is a fear that they may be locked to each other with the longitudinal ends dislocated forward or rearward and inclining upward or downward. As a result, the connector housings may not be fitted normally on each other. Preferably, in this case, the locking means act to lock the connector housings together at both ends of the connector housings in their elongation direction and the spring means comprises springs likewise act on the housings at both their ends. 
     Preferably, one of the connector housings comprises a housing portion to receive electrical terminals and a casing which receives the housing portion, the housing portion being slidable in the casing in the direction of fitting of the connector housings to each other. The lever is rotatably mounted on the housing portion and has a cam surface, while the other connector housing has a cam follower which engages this cam surface during fitting of the connector housings together. The casing is engageable with the lever so that by its rotation the lever holds the casing and the housing portion together. The locking means and spring means are provided on, and act between, the casing and the other connector housing. With the connector housing portion accommodated in the casing located at the front side, this connector portion is fitted in the other connector housing. Then, the casing is pressed. As a result, the lever rotates. The connector housings are fitted to each other with a small force owing to the action of the lever. When they are normally fitted in each other, the casing is locked to the other connector housing, and the connector housings are held in a normal fitting state. If they are left in an incomplete state, the casing is pressed backward by the urging force of the spring means. This state is detected. In particular, the spring means is provided between the other housing and the casing. Thus, a small spring force is amplified by the lever to to separate the housings from each other. That is, it is possible to set the spring force to a low level. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described by way of non-limitative example, with reference to the accompanying drawings, in which: 
     FIG. 1 is an exploded plan view of a connector which is an embodiment of the present invention. 
     FIG. 2 is an exploded sectional view of the connector of FIG.  1 . 
     FIG. 3 is a front view of the a male housing of the connector of FIG.  1 . 
     FIG. 4 is a front view of the female housing of the connector of FIG.  1 . 
     FIG. 5 is a front view of a casing of the connector of FIG.  1 . 
     FIG. 6 is a side view of the casing of FIG.  5 . 
     FIG. 7 is an exploded perspective view of a spring holder of the connector of FIG.  1 . 
     FIG. 8 is a plan view of the spring holder of FIG.  7 . 
     FIG. 9 is a side view of the spring holder of FIG.  7 . 
     FIG. 10 is a partly cut-away plan view of the connector of FIG. 1 showing a state in which the housings have not been fitted in each other. 
     FIGS. 11 to  18  are partly cut-away plan views of the connector of FIG. 1 in successive states during the fitting operation. 
     FIG. 19 is a partly cut-away plan view of the connector of FIG. 1 showing a locked state at completion of fitting. 
     FIGS. 20A,  20 B and  20 C are sectional views of the state of parts of the connector of FIG. 1 immediately before the holding arm is unlocked. 
     FIGS. 21A,  21 B and  21 C are sectional views of the state of parts of the connector of FIG. 1 immediately before locking. 
     FIGS. 22A,  22 B and  22 C are sectional views of parts of the connector of FIG. 1 in the locked state. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A connector embodying the present invention is shown in FIGS. 1 to  22 . As shown in FIGS. 1 and 2, the connector has a male-side connector housing  10  (hereinafter referred to as male housing  10 ) and a female-side connector housing portion  20  which, with the casing  30  described below forms a female housing of the connector. For convenience the portion  20  is called below the female housing  20  and is to be fitted in the male housing  10 . In the description below, the side at which each of the male and female housings  10 ,  20  fit to each other is designated as the front side. 
     The male housing  10  is formed by combining two pieces made of synthetic resin material. As shown in FIG. 3, the male housing  10  has a body part  11  having an elongate width direction and generally rectangular. A small hood part  12  projects forward from the body part  11 . An installing plate  13  for use when the connector is installed on a panel or the like (not shown) is formed at the base of the hood part  12 . 
     An array of cavities  14  is formed in rows widthwise in the body part  11 . Male terminal metal fittings (not shown) are inserted into respective cavities  14  from the rear side and held therein, with tabs thereof projecting into the hood part  12 . The male terminal metal fittings are locked by retainers  15  to prevent their removal from the cavities  14 . 
     The female housing  20  is also made of synthetic resin material. The female housing  20  has a body part  21  which can be received in the hood part  12  of the male housing  10  and a large hood part  22  which is located around the periphery of the body part  21  and can be fitted outside the smaller hood part  12 . The large hood part  22  extends from a position a little rearward from the centre in a front-to-back direction of the female housing  20  to the plane of the front end surface of the body part  21 . 
     An array of cavities  24  is formed in the female housing  20  in correspondence to the cavities of the male housing  10 . Female terminal metal fittings (not shown) are inserted into respective cavities  24  from the rear side thereof, and locked by retainers  25  to prevent their removal from the cavities  24 . 
     A seal ring  26  is fitted on the peripheral surface of the body part  21  of the female housing  20  at the base of the large hood part  22 . In use the seal ring  26  is elastically sandwiched between the peripheral surface of the large hood part  22  and the front side of the small hood part  12  of the male housing  10 . 
     As shown in FIG. 5, the casing  30  also made of synthetic resin material is rectangularly cylindrical and is longitudinally slidable on the periphery of the female housing  20 . A pair of cantilevered locking arms  31  project forward from the middle of the right and left inner side surfaces of the casing  30 . As shown in FIG. 2, projections  31 A are formed on the opposed surfaces of the locking arms  31  at their front ends. Each locking arm  31  is elastically deformable in the right-to-left direction so that the locking arms  31  may approach each other. 
     As shown in FIG. 4, at the middle of each of right and left side surfaces of the large hood part  22  of the female housing  20 , pair of guide rails  27  extends in the front-to-back direction. These rails slidably guide the respective locking arm  31 , which becomes located between the guide rails  27 . As shown in FIG. 2, an insertion groove  28  open forward is formed in the hood part  22  at the central portion between the guide rails  27 . The groove  28  extends to a position at about the middle of the entire length of the guide rails  27  in the front-to-back direction. Near the front ends of the guide rails  27 , a pair of locking portions  29  to be locked to the front end surface of the projection  31 A of the locking arm  31  are formed on each side of the insertion groove  28 . The pair of locking portions  29  can be locked to the projection  31 A. 
     As shown by an arrow in FIG. 2, when the female housing  20  is inserted into the casing  30  from the rear thereof, the locking portions  29  strike the projections  31 A so that the two locking arms  31  elastically deform outward. When the locking portions  29  pass the projections  31 A, the locking arms  31  elastically deform inward, to be restored to their original state. The projections  31 A thus lock against the rear surfaces of the locking portions  29 , to prevent the female housing  20  being removed rearwardly from the casing  30 . 
     Release projections  16  capable of penetrating into the insertion grooves  28  are formed at about the middle of the right and left outer side surfaces of the small hood part  12  of the male housing  10 . A corner of each release projection  16  at its front end is formed as a tapered guide surface  16 A. When the release projection  16  penetrates into the insertion groove  28  from the front side thereof, the guide surface  16 A strikes the front end of the projection  31 A, thus deforming the locking arm  31  elastically outward. As a result, the locking portion  29  is unlocked from the locking arm  31 , and the female housing  20  is allowed to move rearwardly inside the casing  30 . 
     A pair of levers  40  for assisting the fitting of the male housing  10  and the female housing  20  is symmetrically mounted on the upper and lower surfaces of the female housing  20 . The two levers  40  are joined by a cross-bar (not shown) so that they move together in tandem. As shown in FIG. 1, each lever  40  is wide at a first end and tapered towards its other end. A curved driving cam slot or groove  41  is formed in the first end of the lever  40 , with an entrance opening  41 A at an edge of the lever. A pin  42  around which a flange partly extends stands up from the other side of the lever  40 . 
     A bearing hole  43  is formed in the lever  40  near the inward end of the driving cam groove  41 . A shaft  44  stands up on the upper surface of the large hood part  22  of the female housing  20  near the right (lower side in FIG. 1) end of the upper surface of the large hood part  22 . The lever  40  is rotatably supported by fitting of the shaft  44  in the bearing hole  43 . The other lever  40  is correspondingly fitted. 
     As shown in FIGS. 1 and 2, a cam groove  45  is formed on the upper surface of the casing  30 , at one side (upper side in FIG. 1) from the widthwise centre of the upper surface of the casing  30 . The operation pin  42  of the lever  40  can be fitted in the cam groove  45  slidably and without play. As shown in FIG. 2, a first part  46  providing an entrance of cam groove  45  extends in the insertion direction (arrow in FIG. 2) and its base part bends to extend slightly rearwardly and almost perpendicular to the first part. 
     The operation pin  42  is introduced into the cam groove  45  through the entrance  46 , with the lever  40  supported by the female housing  20 . In this state, the female housing  20  is pressed into the position at which the locking arms  31  prevents the removal of the female housing  20  in the rearward direction. As a result, as shown in FIG. 10, the operation pin  42  is located at a start end  45 A of the base part of cam groove  45 , and the lever  40  is held so that the entrance  41 A of its driving cam groove  41  faces forward. 
     A pair of follower pins  18  which can be fitted slidably without play in the two driving cam grooves  41  stand upwardly on the upper and lower surfaces respectively of the small hood part  12  of the male housing  10  at the same positions relative to the centre of the housing  10 . 
     The male and female housings  10 ,  20 , have locking means for locking them to each other in a normal fit-in state and a spring means for detecting whether the housings  10 ,  20  have been normally fitted in each other. The locking means and the spring means are described below. 
     An accommodation part  50  is provided at the middle region of the right and left side surfaces of the casing  30 . The accommodation part  50  has a pair of spaced side walls  51  (see FIG.  6 ). Outwardly, the accommodation part  50  is covered by an arch portion  52 . 
     As shown at the lower side of FIG. 2, each accommodation part  50  accommodates an elongate locking arm  54 , connected at the inner surface of its centre portion in its longitudinal direction with the bottom surface of the accommodation part  50 . The locking arm  54  is elastically deformable in a see-saw member on the connected point. About the half of the front portion of the locking arm  54  is located inside the arch portion  52 . A hook-shaped locking claw  55  is formed at the front end of the locking arm  54 . The front end surface of the locking claw  55  is formed as a tapered surface  55 A. 
     A pair of right and left locking hooks  57  project forwardly from the installing plate  13  of the male housing  10  opposite the respective locking arms  54  of the casing  30 . The locking hooks  57  are elastically deformable. Window holes  58  into which the locking arms  31  of the casing  30  can penetrate are formed in the plate  13  inwardly of the roots of the locking hooks  57 . Receiving portions  59  are formed on the rear surface of plate next to the holes  58 . When the locking arm  31  penetrates into the window hole  58  and engages the receiving portion  59  at its inner side, the locking hook  57  is prevented from deforming inward elastically. 
     Thus, when the casing  30  is fitted in the male housing  10 , initially, the locking arm  31  penetrates into the window hole  58  along the inner side of the locking hook  57 , thus preventing the inward elastic deformation of the locking hook  57 . When the locking hook  57  strikes the tapered surface  55 A, the locking arm  54  is pivoted. When the casing  30  has been inserted into a predetermined position on the male housing  10 , the locking claw  55  becomes locked to the rear surface of the locking hook  57 , with the locking arm  54  pivoting elastically back into its original state. In this manner, the removal of the casing  30  from the housing  10  is prevented. 
     Each accommodation part  50  also accommodates a spring holder  60  covering the locking arm  54  (see FIGS. 7 to  9 ). The spring holder  60  incorporates coil springs  61  described later. The holder  60  is a separate part, inserted in the accommodation part  50 . Guide rails  63  provided at right and left ends of a base portion or substrate  62  of the holder  60  are inserted into grooves  51 A of side walls  51  of the accommodation part  50  such that the guide rails  63  are slidable longitudinally (see FIG.  22 ). The spring holder  60  is prevented from moving forward when it strikes a front plate  52 A of the arch portion  52 . The spring holder  60  is prevented from moving rearward when a pair of projections  64  and another pair of projections  65  formed on the upper and lower surfaces thereof respectively, are locked to locking portions  66  and  67  (see FIGS. 22 and 6) of longitudinally extending insertion grooves formed on the lower surface of the arch portion  52  and on the bottom surface of the accommodation part  50 , respectively. 
     As shown in FIG. 8, the holder  60  has an operation portion  68  (lever or tab) elastically deformable due to the formation of slits at both sides thereof formed at the widthwise centre of the rear side of the holder  60 . When the spring holder  60  is located at the rear position shown in FIG. 22, the operation portion  68  is located at a position immediately over the locking arm  54 . 
     As shown in FIG. 20, a relief groove  70  is formed at the widthwise centre of the lower surface of the substrate  62 . The relief groove  70  extends rearward from a position located a little rearward from the front end of the substrate  62 . When the spring holder  60  is located at a front position, the front end of the relief groove  70  corresponds to the front end of the locking arm  54 , thus allowing the front end of the locking arm  54  to pivot outward elastically, as shown in FIG.  20 B. 
     The front surface of the relief groove  70  is formed as a restriction surface  71  which strikes the front end of the elastically pivoted locking arm  54 , thus preventing a rearward movement of the spring holder  60 . 
     A pair of spring accommodation chambers  73  is longitudinally formed on the lower surface of the substrate  62  of the spring holder  60  on opposite sides of the locking arm  54 . Each chamber  73  accommodates the coil spring  61  in a natural state in such a manner that the coil spring  61  is prevented from moving forward. A spring seat  74  is fitted on the front end of the coil spring  61 . About half of the inner side of the front surface of the chamber  73  is open. Thus, the spring seat  74  faces the opening of the front surface of the chamber  73  when the coil spring  61  is in the chamber  73 . 
     A holding arm  75  having a hook  76  at its front end is formed integrally on the holder  60  laterally outwardly from each spring accommodation chamber  73 . The holding arm  75  extends forward and is cantilevered and elastically deformable. As shown in FIG. 20A, a forward movement of the spring holder  60  is prevented when the hook  76  of the holding arm  75  is caught by a catching portion  77  formed on the bottom surface of the accommodation part  50 . 
     As shown in FIGS. 1 to  3 , a pair of L-shaped ribs  79  projects in opposite directions from both sides of each locking hook  57  of the male housing  10 . The ribs  79  are capable of penetrating into the arch portion  52  from the front thereof, with the ribs  79  sandwiching the locking arm  54  therebetween when the casing  30  is fitted on the male housing  10 . A horizontal leg  79 A of the rib  79  shown in FIG. 3 is capable of pressing the coil spring  61  through the spring seat  74 . The front end of a vertical leg  79 B of the rib  79  contacts the holding arm  75 , thus so deforming the hook  76  elastically that the hook  76  is unlocked from the catching portion  77 . 
     The holding arm  75  is unlocked from the catching portion  77  immediately before the locking arm  54  returns to its original position (see FIG. 19) as a result of complete fitting of the casing  30  in the male housing  10 . 
     The operation of the lever-type connector of this embodiment is described below. 
     The female terminal metal fittings are accommodated in the female housing  20  and locked by the retainers  25 . When the female housing  20  is inserted into the casing  30  from the rear thereof, as shown by an arrow in FIG. 10, the locking portion  29  is locked to the locking arm  31 , with the operation pin  42  of the lever  40  fitted on the start portion of the operation cam groove  45 , and the casing  30  is mounted on the periphery of the female housing  20  in such a manner that the longitudinal movement thereof is prevented. At this time, the entrance  41 A of the driving cam groove  41  of the lever  41  faces forward. 
     The male terminal metal fittings are located in the male housing  10  and locked by the retainers  15 . 
     In this state, the casing  30  mounted on the female housing  20  is fitted on the outer side of the small hood part  12  of the male housing  10 . As shown in FIG. 11, each follower pin  18  of the male housing  10  enters the entrance  41 A of the driving cam groove  41  of the corresponding lever  40 . Next, as shown in FIG. 12, the locking arm  31  rides on the release projection  16  and deforms outward elastically. As a result, the locking portion  29  is unlocked from the locking arm  31 . Therefore, the female housing  20  is capable of moving rearward inside the casing  30 . 
     When the casing  30  is further pressed towards the male housing  10 , as shown in FIG. 13, the cam groove  45  presses the operation pin  42  forward. Thus, the lever  40  is rotated counterclockwise on the shaft  44 . As the follower pin  18  moves to the rear side of the driving cam groove  41 , the two housings  10 ,  20  approach each other owing to the action of the levers. At this time, as shown in the lower side of FIG. 13, the locking arm  31  that has deformed outward elastically interferes with the locking hook  57  of the male housing  10 , thus deforming the locking hook  57  outward elastically. 
     With further progress of the fitting operation, as shown in FIG. 14, with the locking arm  31  and the locking hook  57  returning to the original state, the locking arm  31  penetrates into the window hole  58  along the inner side of the locking hook  57 . As a result, the inward elastic deformation of the locking arm  31  is prevented, and the inward elastic deformation of the locking hook  57  is also prevented. In this state, as shown in the lower side of FIG. 15, the locking hook  57  strikes the tapered surface  55 A of the locking claw  55  of the locking arm  54 . Then, as shown in FIG. 16, the locking hook  57  presses the tapered surface  55 A. As a result, the locking claw  55  deforms outward elastically, penetrating into the relief groove  70  of the spring holder  60 . 
     At this time, as shown in the upper side of FIG. 16, the rib  79  of the male housing  10  penetrates into the arch portion  52 , and each horizontal portion  79 A contacts the corresponding spring seat  74 . 
     As shown in FIG. 20A, the holding arm  75  is caught by the catching portion  77 , and as described above, the front end of the locking arm  54  is fitted in the relief groove  70  of the spring holder  60  and thus locked to the restriction surface  71 . Therefore, the spring holder  60  is prevented from moving rearward. 
     Therefore, with further penetration of the rib  79  into the arch portion  52 , as shown in the upper side of FIG. 17, the coil spring  61  is gradually compressed by the spring seat  74 . Meanwhile, the two housings  10 ,  20  are further approached to each other owing to the action of the levers. 
     In this state, the terminal metal fittings of both housings  10 ,  20  are deeply connected with each other and the fitting resistance increases. Thus, there is a possibility that the fitting operation is stopped erroneously, i.e. the housings  10 ,  20  may be left incompletely fitted together. In this case, the casing  30  is so urged that it moves away from the male housing  10  by the restoring elastic force of the coil springs  61 . Further, the two housings  10 ,  20  are separated from each other by the rotation of the lever  40  in the opposite direction. Thereby, it is possible to detect that the housings  10 ,  20  are incompletely fitted. 
     Immediately before the locking claw  55  rides over the locking hook  57  as a result of continuation of the fit-in operation as shown in FIG. 18, the vertical portion  79 B of the rib  79  proceeds to a position immediately before the holding arm  75  and strikes the tapered surface  76 A of the hook  76 , as shown in FIG.  20 A. Then, as shown in FIG. 21A, the holding arm  75  continues to deform elastically and is released from the catching portion  77 . At this time, as shown in FIG. 21B, the restriction surface  71  contacts the locking claw  55  which is still deformed elastically. Therefore, the spring holder  60  is prevented from moving rearward, although the elastic restoring force of the coil spring  61  is applied to the spring holder  60 . 
     With further progress of the fitting operation, the locking claw  55  of the locking arm  54  rides across the hook  57  and is locked to the rear surface of the hook  57  by returning to its original state. Now, the housings  10 ,  20  are fitted in each other normally, and the casing  30  and the male housing  10  are locked to each other. 
     Further, the locking claw  55  is unlocked from the restriction surface  71  by the above locking operation. Thus, the restoring elastic force of the coil spring  61  causes the spring holder  60  to move to the retreat position and the coil spring  61  returns to its natural state. See FIG.  22 . 
     To unlock the housings  10  and  20  from each other, the operation portion  68  is pressed forward in the state shown in FIG. 22 to move the spring holder  60  to the forward position, and is pressed downward to deform elastically. As a result, the rear side of the locking arm  54  is pressed and the locking claw  55  so deforms that it moves into the relief groove  70  of the spring holder  60 . Thereby, the hook  57  is unlocked from the locking claw  55 , and the rib  79  of the male housing  10  is pressed downward by the force of the coil springs  61  stored by the pressing of the spring holder  60 . Consequently, the separation of the casing  30  from the male housing  10 , namely separation of the male housing  10  from the female housing, is accomplished. 
     As is apparent from the foregoing description, in this embodiment, when the fitting operation is stopped before the housings  10 ,  20  are fitted in each other normally, the urging force of the coil spring  61  causes the male housing  10 , the casing  30 , and the female housing  20  to separate from each other. This allows an operator to securely detect whether the housings  10 ,  20  have been fitted in each other normally. 
     When the housings  10 ,  20  are fitted in each other normally and locked to each other, the restraint of the spring holder  60  is released, and the compression state of the coil springs  61  is released, so that the spring holder  60  is moved rearward. That is, when the housings  10 ,  20  are fitted in each other normally, the spring force does not act to separate the housings  10 ,  20  from each other. 
     The construction of the lever-type connector is that the casing  30  serving as the operation portion of the lever  40  is provided for the female housing  20  and the return coil spring  61  is provided between the casing  30  and the male housing  10 . A small spring force is amplified by the lever  40  to such a high extent as to separate both housings  10  and  20  from each other. That is, it is possible to select a small spring force. 
     The present invention is not limited to the embodiment explained above. For example, the following embodiments are included in the technical scope of the present invention. Further, various modifications can be made without departing from the spirit and scope of the present invention. 
     (1) The locking mechanism and the spring mechanism may be provided on only one surface. 
     On the other hand, if the connector is widthwise long and narrow, it is preferable to provide the connector housings with the locking mechanism and the spring mechanism at both sides in the longitudinal direction thereof. 
     That is, when the connector housings are long and narrow, there is a fear that they are locked to each other, with the longitudinal ends dislocated forward or rearward and inclining upward or downward. As a result, the front ends or the rear ends of the connector housings that has been dislocated rearward may not be fitted normally on each other. 
     According to the lever-type connector of the present invention, because the locking mechanism and the spring mechanism are provided at both sides of the connector housings in the longitudinal direction thereof, it is possible to lock the connector housings to each other when both longitudinal ends thereof are normally fitted in each other. Thus, both connector housings can be held in the normal fit-in state in the whole region of the longitudinal direction thereof. 
     (2) In the above-described embodiment, the coil spring has been described as an example of the return spring. But other kind of spring such as a leaf spring may be used. 
     (3) The spring holder and the locking arm may be set on the male housing. 
     (4) The present invention is applicable to a type of a connector having the lever provided exposed to the outside as well as to the type of connector incorporating the lever interiorly. 
     While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.