Abstract:
A electrical connector includes a housing ( 11 ) with a peripheral wall and a front projection ( 17 ) that extends from said peripheral wall in the plugging direction so as to plug in a dent portion ( 43 ) of a mating connector ( 30 ) thereby providing a large plugging length without increasing the connector size.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to an electrical connector having a plug-in face with a mating electrical connector, which is provided in a peripheral wall of a housing and extends in a plug-in direction of the connector. 
   2. Description of the Related Art 
   This kind of electrical connector is disclosed in, for example, Japanese Patent Application Kokai Number 2002-33150. It discloses a board-side connector, which is fixed to a circuit board, and a cable connector, which is plugged-in the board-side connector and furnished with a cable. The housing of the board-side connector has an appearance of a substantially rectangular parallelepiped. The housing comprises a hollow opened upwardly for receiving the cable connector or a mating connector. One of four sidewalls forming the hollow is opened sideways within the full range of the depth of the hollow. When the cable connector is plugged-in the board-side connector from the above, the cable of the cable connector extends from a side opening of the hollow of the board-side connector. 
   Since, as described above, one of the four sidewalls of the hollow of the board-side connector is opened sideways widely, the cable connector is guided by the plug-in faces formed on the internal surfaces of the remaining three sidewalls of the hollow. Since the three plug-in faces are formed in the same range of height, the plug-in between both the connectors starts and finishes simultaneously at the three plug-in faces. 
   The plug-in face that is long in the plug-in direction is generally preferable. Especially, when the cable of the cable connector extends sideways, since part of the peripheral wall of the housing is opened for extension of the cable, the plug-in face becomes small in area. Accordingly, a lengthy plug-in face is required to secure large area for the plug-in. In the example in Patent Document 1, since the three plug-in faces are provided in the same range in the plug-in direction, the plug-in operation starts and finishes simultaneously at all the plug-in faces. Accordingly, if a connector with large dimension in the plug-in direction is acceptable, a large plug-in length is allowed. However, if a small dimension of connector is required, the plug-in length becomes too large. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to provide an electrical connector having a sufficient plug-in length with small dimension in the plug-in direction. 
   The present invention relates to first and second connectors that are plugged in each other. 
   First Connector: 
   The first connector includes a housing with a peripheral wall and a plug-in face provided on the outer surface of the peripheral wall and extended in the plug-in direction. A cable extends in a direction perpendicular to the plug-in direction. The housing includes a front projection extending in the plug-in direction from the front end of the housing for being plugged in a dent portion of a mating connector. 
   The front projection cooperates with other plug-in faces for plugging guidance. That is, the plug-in length is elongated by the front projection. The front projection is provided on such a portion of the front face of the housing that the strength of a bottom wall of the housing is not affected. Thus, the connector with a cable can have a satisfactory plug-in face upon plug-in with the mating connector. 
   It is preferred that the front projection is provided on an even number of corners of the housing so that the distance between the front projections can be maximized and oblique plugging between the connectors is minimized. 
   A peripheral projection projects from the peripheral wall in a direction perpendicular to the plug-in direction and plugged in a plug-in space provided in the peripheral wall of a mating connector. By providing the peripheral projection within the wall of the connector, it is possible to provide not only a large plug-in face without increasing the width of the connector but also a large plug-in length in cooperation with the front projection. The peripheral projection may be provided on each of opposed side walls of the housing. It is preferred that the peripheral projections are spaced as far as possible so that inclined plugging can be prevented. 
   The peripheral projection is made so as to serve as a cable extension from which a cable extends in the same direction as the peripheral projection. Thus, it has two functions; i.e., plugging guidance and cable support. 
   Two peripheral projections are provided on each of opposed side walls of the housing so that the housing has an H-shaped form as viewed in the plugging direction. 
   Second Connector: 
   A plug-in face is provided on an inner surface of a peripheral wall of a housing of the second connector and extends in the plugging direction. A cut-off portion is provided in the sidewall so as to allow the extension of a cable in a direction of the plugging direction. A dent portion is provided in the bottom of the housing for receiving the front projection of the first connector. 
   The dent portion works with the front projection of the first connector for plugging guidance. It increases the plugging length as the front projection does. It is provided in a portion of the bottom so that it neither decreases the bottom strength nor increases the connector height because it is made in the bottom wall. 
   It is preferred that the dent portion is provided in each of an even number of corners of the bottom. Since they are provided at the corners, the distance between them is maximized so that the inclined plugging is minimized. The plug-in space is made in the peripheral wall for receiving the peripheral projection of the first connector. 
   By making the plug-in space within the wall thickness, it is possible to provide a large plug-in face and maximize the plug-in length in cooperation with the dent portion. The plug-in space may be provided in each of opposed sidewalls of the housing. The plug-in spaces are spaced so much that inclined plugging is prevented. 
   The plug-in space may be a groove portion extending halfway in the sidewall or a cut-off portion passing through the sidewall. Both the groove portion and the cut-off portion work as plugging guidance. In addition, the cut-off portion receive the cable extension. 
   One of opposed sidewalls of the housing has a pair of groove portions and the other has a pair of cut-off portions so that the plug-in space has an H-shaped form as viewed in the plugging direction. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a pair of electrical connectors according to the first embodiment of the present invention showing the condition before plug-in; 
       FIG. 2  is a sectional view of the connectors taken along the line II-II of  FIG. 1 ; 
       FIG. 3  is a sectional view of the connectors taken along the line III-III of  FIG. 1 ; 
       FIGS. 4(A) and 4(B)  are sectional views of the connectors upon start of the plug-in operation, wherein  4 (A) shows a sectional view at a position corresponding to  FIGS. 2 and 4(B)  shows a sectional view at a position corresponding to  FIG. 3 ; 
       FIGS. 5(A) and 5(B)  are sectional views of the connectors in the course of the plug-in, wherein  5 (A) shows a sectional view at a position corresponding to  FIGS. 2 and 5(B)  shows a sectional view at a position corresponding to  FIG. 3 ; and 
       FIGS. 6(A) and 6(B)  are sectional views of the connectors upon completion of the plug-in operation, wherein  6 (A) shows a sectional view at a position corresponding to  FIGS. 2 and 6(B)  shows a sectional view at a position corresponding to  FIG. 3 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The embodiments of the present invention will now be described with reference to the accompanying drawings. 
   In  FIG. 1 , the first electrical connector  10  comprises a housing  11  of a rectangular parallelepiped with longitudinal sidewalls  11 A and  11 B in an arrangement direction of terminals. Two peripheral projections  8  extend outwardly from the sidewall  11 A at an interval and two peripheral projections  9  extend outwardly from the opposed sidewall  11 B at the interval. Accordingly, the housing  11  has a plane H-shaped form when viewed in a plug-in direction of the connector. The peripheral projections  8  and  9  are plugged in a plug-in space formed by utilizing the thickness of sidewalls of a second connector  30 . The projection  8  is used as an extension portion for a cable with a terminal. A terminal holding portion is provided in the housing  11  between the peripheral projections  8  and  9 . 
   In  FIGS. 1 and 2 , the housing  11  has two holes  12 , which are opened to the end of the projections  8 . A terminal  13  crimped at the end of a cable C is inserted into the hole  12 . As best shown in  FIG. 3 , an outer covering C 1  at the end portion of the cable C is removed by a predetermined length to expose a core wire C 2 . The terminal  13  comprises a first hold portion  13 A for tightly holding the outer covering C 2  of the cable C, a second hold portion  13 B for tightly holding the core wire C 1 , a leg portion  13 C for stabling the position and posture of the terminal  13  in the hole  12 , and a leg-like contact portion  13 D for being brought into contact with a plate terminal of the mating connector. 
   The first and second hold portions  13 A and  13 B function as a crimp portion for the cable. That is, a pair of legs extending from a U-shaped cable accommodation portion is rounded by caulking or crimping so as to tightly hold the outer covering C 1  and core wire C 2 . The leg portion  13 C extends in a direction receding from the core wire C 2  and the top end (lower end) of the leg portion  13 C is touched with the bottom of the hole  12  to stable the position and posture of the terminal  13 . The contact portion  13 D provided on the top side (right-hand side) of the terminal  13  extends downwardly like the leg portion  13 C. As shown in  FIG. 2 , a throat portion  13 D 1  is provided in the contact portion  13 D to receive and be brought into resilient-contact with the plate terminal of the mating connector. 
   In  FIG. 3 , the hole  12  passes through from an opening  12 A provided at a side face of the housing  11  to a sidewall  12 B provided at an opposite side face of the housing  11 . The leading end of the terminal  13  abuts against the sidewall  12 B so as to control the depth of the insertion of the terminal with the cable C. The hole  12  is provided with slits  12 D and  12 E passing through the lower wall and the opposite side face of the housing  11 , respectively. The slits  12 D and  12 E form flat spaces in parallel to the sheet of  FIG. 3  to permit the contact portion of a plate terminal of the mating connector to pass through. The lower end of the slit  12 D is tapered to provide a guide portion  12 D 1  to facilitate of the insertion of the contact portion. 
   As shown in  FIGS. 1 and 2 , a pair of resilient arms  14  extends downwardly from the upper edges of sidewalls that extend perpendicular to the longitudinal sidewalls  11 A and  11 B. The resilient arm  14  is linked to the housing  11  by a base portion  14 A. The base portion  14 A is made thinner than the other parts to provide resilient deformation. The resilient arm  14  is enlarged toward the end thereof and extends almost up to the lower edge of the housing  11 . That is, the resilient arm  14  is placed in the dimension of the housing  11  in the vertical direction. A flat operational portion  14 B is provided on a lower outside of the resilient arm  14 . 
   Lock portions  15  project from the side faces of the resilient arm  14 . The lock portions  15  are integrally provided with the resilient arm  14  at a position overlapping that of the operational portion  14 B in the extension direction of the resilient arm  14 . The lock portion  15  is flat at the inner face facing to the housing  11  and tapered at the outer faces  15 A and  15 B. The two taper faces  15 A and  15 B are provided such that the thickness of the lock portion  15  decreases on the upper and the lower sides. 
   A receiving hollow  16  is provided under the housing  11  between inner surfaces  8 ′ and  9 ′ of the peripheral projections  8  and  9 . The receiving hollow  16  penetrates in a direction perpendicular to the sheet in  FIG. 2  for receiving an intermediate land  42  of the mating connector. The receiving hollow  16  is furnished with a tapered guide portion  16 A to receive the intermediate land  42  easily. 
   A front projection  17  and a stepped portion  17 ′ extend downwardly from the bottom of the projection  8 , that is, they are provided at a part of the front portion of the projection  8  in the plug-in direction. A stepped portion  17 ′ is provided on a side of the front projection portion  17 . The front projection  17  is inserted into a dent portion  43  provided in the bottom wall of the mating connector  30 . In this embodiment, the width of the front projection  17  is made to be within the thickness of the peripheral wall of the mating connector  30  and the length of the front projection  17  is made to be within the depth of the dent portion  43 . The dent portion  43  may penetrate into the bottom of the housing  11 . 
   In  FIG. 1 , a housing  31  of the mating connector or second connector  30  comprises a bottom wall  32  and a peripheral wall including sidewalls  33 ,  34 ,  35 , and  36  standing upright on the four sides of the bottom wall  32 . The sidewalls  33 ,  34 ,  35 , and  36  form an accommodation space for receiving the first electrical connector  10  and are furnished with tapered guide portions  33 A,  34 A,  35 A, and  36 A, respectively, to facilitate the insertion of the first connector  10 . 
   In  FIG. 3 , two grooves  32 A passing through the bottom wall  32  vertically are provided at positions corresponding to the slits  12 D of the first connector  10 . A plate terminal  37  of the second connector  30  has a connection portion  37 A, which is press-fitted into each of the grooves  32 A. The terminal  37  comprises a leg-like connection portion  37 A, which extends outside the housing  31  to be inserted into and connected with a corresponding hole of a circuit board (not shown) and a plate-type contact portion  37 B, which is inserted into the throat portion  13 D 1  of the terminal  13  of the first connector  10 . As shown in  FIGS. 1 and 3 , the contact portion  37 B are placed on the right-hand side of the second connector  30  at a position corresponding to the throat portion  13 D 1  of the first connector  10  and there is nothing on the left-hand side of the contact portion  37 B to form a space for receiving the first connector  10 . 
   As shown in  FIG. 1 , a pair of the sidewalls  34  and  34 ′ and another pair of the sidewalls  35  and  35 ′ are provided symmetrically and opposing to each other. Cut-off portions  38  and  39 , which are opened upwardly for receiving the resilient arms  14  of the first connector  10 , are provided between the sidewalls  34  and  34 ′, and  35  and  35 ′, respectively. Engagement hooks  40  and  41  project to the inside of the cut-off portions  38  and  39  from the sidewalls  34 ,  34 ′,  35 , and  35 ′. The engagement hooks  40  and  41  are provided at positions corresponding to the positions of the lock portions  15  of the resilient arms  14 . Tapered guide portions  40 A and  41 A are provided on the top of the engagement hooks  40  and  41  to facilitate the start of the engagement operation. 
   A groove portion  33 D and a cut-off portion  36 B are provided on the sides of the sidewalls  34  and  35  of the accommodation space, respectively. Accordingly, the accommodation space has a plane H shape when viewed in the plug-in direction. The two groove portions  33 D are provided in the sidewall  33  to provide plug-in spaces for the projections  9 , which are placed at the positions corresponding to the cables C. Namely, the end of the projection  9  is guided and plugged in the groove portion  33 D from the above. A ditch  33 B is provided in the bottom of the groove portion  33 D to guide the plate terminal  37  when the connection portion  37 A of the plate terminal  37  is press-fitted in the groove  32 A from the above, and to support the terminal  37  after the press-fit. Tapered portion  33 C is provided at the upper part of the ditch  33 B to make easy the guidance of the terminal  37 . 
   Two cut-off portions  36 B are provided in the sidewall  36  and opened upwardly to provide plug-in spaces for the projections  8 , which are placed at the positions corresponding to the two cables C extending from the first connector  10 . A post  36 C is provided between the two cut-off portions  36 B and furnished with wall faces  36 D. The post  36 C is inserted into the receiving hollow  16  of the first connector  10  from the underside with guidance of the front projections  17  and the inner surfaces  8 ′ of the projections  8 . Thus, the post  36 C can be inserted with guidance of the wide area of the front projections  17  and the inner surfaces of the projections  8 . The post  36 C and the sidewall  33  are linked with the intermediate land  42  for reinforcement of the second connector  30 . The intermediate land  42  is plugged in the receiving hollow  16  that is provided under the first connector. 
   A dent portion  43  is provided in the bottom of the cut-off portion  36 B for receiving the front projection  17  of the first connector  10 . The dent portion  43  is provided in the range of the thickness of the sidewall  36  in the thickness direction of the sidewall  32  and within the thickness of the bottom wall  32  in the plugging direction. The dent portion  32  may pass through the housing  41 . 
   The electrical connectors  10  and  30  are electrically connected as described below. 
   Terminals  13  crimped to the cable C are inserted into the holes  12  ( FIGS. 2 and 3 ). 
   The first connector  10  with the cable C is plugged in the second connector  30 . In  FIGS. 4(A) and 4(B) , the projection  8  and  9  of the first connector  19  are guided and plugged in the cut-off portion  36 B and the groove portion  33 D of the second connector  30 . Also, the intermediate land  42  of the second connector  30  is inserted into the receiving hollow  16  of the first connector  10 . 
   When the plug-in advances further, as shown in  FIGS. 5(A) and 5(B) , the front projections  17  of the first connector start to be plugged into the dent portions  43  of the second connector. Thus, the plugs-in of the front projections  17  and the peripheral projections  8  and  9  are finished simultaneously. 
   Since the plug-in of the front projection  17  starts just before the plug-in of the peripheral projections  8  and  9  is finished, the total plug-in length in the plug-in direction becomes large. Accordingly, the posture of the connector  10  becomes stable with respect to the connector  30 . Especially, a revolution around an axis in the plug-in direction and an inclination with respect to the axis are eliminated so that the smooth pug-in is performed. Also, since the peripheral projections  8  and  9  and front projections  17  are guided and plugged-in by utilizing the peripheral and bottom walls of the second connector  30 , the second connector  30  becomes small. 
   When the plug-in of the first connector  10  into the second connector  30  is completed, the contact portion  37 B of the terminal  37  enters the throat portion  13 D 1  of the contact portion  13 D of the terminal  13  of the first connector  10 , making the electrical connection between the connectors  10  and  30 . 
   Also when the plug-in is finished, the cables C provided in the connector  10  extend outwardly from the cut-off portion  36 B of the housing  31  of the connector  30 , and the resilient arms  14  of the first connector  10  enter the openings  38  and  39  of the connector  30 . 
   The resilient arms  14  is resiliently deformed inwardly to enable the plug-in of the second connector  30  when the lower taper face  15 A of the lock portion  15  receives pushing force from the engagement portion  40  of the connector  30 . As the plug-in further advances, the engagement portion  40  begins to get contact with the upper taper face  15 B. Since the upper taper face  15 B is inclined in reverse to the lower taper face  15 A in respect to vertical direction, when the upper taper face  15 B receives a pushing force from the engagement portion  40 , a downward force, which accelerates the plug-in, is produced. Accordingly, the plug-in operation between the connectors  10  and  30  is performed easily. 
   When the lock portion  15  passes the engagement portion  40 , the resilient arm  14  is released from the resilient deformation into the original free position so that the engagement portion  40  engages with the upper face of the lock portion  15  to prevent the coming off of the connector. Thus, the lock is made. 
   In order to remove the first connector  10  from the second connector  30 , the user pushes the operational portion  14 B toward the housing  11  so that the resilient arm  42  is resiliently deformed for unlocking. When the displacement amount of the deformation reaches an amount necessary for the lock, that is, an amount equal to the thickness of the lock portion  15 , the first connector  10  can be removed from the second connector  30 .