Patent Publication Number: US-7896709-B2

Title: Keyed mating connectors with latching mechanism

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from Japanese Patent Application No. 2007-276603, which was filed on Oct. 24, 2007, the disclosure of which is herein incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a latch-mountable connector housing and an electric connecting device, each of which is capable of reducing an effect from vibration. 
     2. Description of Related Art 
     Japanese Unexamined Patent Publication No. 2006-202557 (Tokukai 2006-202557; hereinafter Patent Document 1) discloses an example of known electric connector. In the electric connector, a metal latch, while being supported in a guide groove of a female housing, applies a preload to the female housing and a male housing, in a direction of fitting these housings with each other. A latch portion provided at a spring part of the metal latch fits in a fixing groove of the male housing, when the female and male housings are fit with each other. This structure realizes an electric connector capable of simply and easily providing a connection, while avoiding a loss in the electric conductivity even under a harsh environment. 
     SUMMARY OF THE INVENTION 
     In the electric connector described in Patent Document 1, the metal latch inhibits separation of the female and male housings from each other. When such an electric connector is adopted in a vehicle or the like, vibration from the engine or the like may affect the electric connector. If the housings of the electric connector are connected to each other with a gap therebetween, the housings may rattle with the vibration. Therefore, the housings may separate from each other, consequently disconnecting the electric connector, even though the metal latch is attached. Further, this vibration-attributed rattling of the housings may cause a damage to the housings due to abrasion. 
     A conceivable approach to reduce such an adverse effect from the vibration is, for example, to strengthen the resiliently-holding-force of the metal latch. This approach however requires modification of the shape of the metal latch such as thickening of the metal latch, and may enlarge or complicate the electric connector. On the other hand, it is preferable that the structure of the metal latch be made simple. 
     As a countermeasure against vibration, the electric connector of Patent Document 1 adopts a plurality of ribs in the male housing. In the female housing on the other hand are formed slits which are arranged to contact the ribs respectively. Specifically, on each of four side surfaces of the male housing formed in a box-like shape, a rib is formed in the middle portion. Further, one of the four side surfaces is provided with two more ribs, one of which is formed at one end of that side surface, and the other one of which is formed at the other end (cf. FIG. 4(a) of Patent Document 1). Further, each rib formed on each of the side surfaces projects in a direction normal to the side surface. Fitting these ribs on the male housing in the slits on the female housing reduces the gap between the both housings. Therefore, the both housings are restrained from rattling, thus achieving a reliable connection of the electric connector. 
     However, an increase in the number of ribs causes an increase in the size and weight of the electric connector, and the electric connector is more likely to be affected by vibration. In view of this, the electric connector is preferably simply structured with a less number of ribs. 
     Thus, it is an object of the present invention to provide a latch-mountable connector housing and an electric connecting device, each of which is simply structured and yet capable of maintaining the connected state while reducing an adverse effect from vibration. 
     To achieve the above object an electric connecting device of the present invention includes: a first connector having a first terminal and a first housing supporting the first terminal; a second connector having a second terminal electrically connectable to the first terminal and a second housing supporting the second terminal; and a latch which inhibits separation of the first and second housings from each other. The first housing has a tube-like fitting and the second housing has a fitting receiver for fitting therein the fitting during a connected state in which the first and second connectors are connected to each other. When viewed from a connecting direction in which the first connector connects to the second connector, one of the exterior surface of the fitting and the interior surface of the fitting receiver has plural ribs each projecting in a radial direction of a center portion of the fitting, and another one of the exterior surface of the fitting and the interior surface of the fitting receiver has plural recesses for respectively fitting therein the ribs during the connected state. The ribs, when viewed from the connecting direction, includes two ribs disposed across from each other over the center portion, along a single line extending through the center portion, on the exterior surface of the fitting or the interior surface of the fitting receiver. 
     In this structure, the first housing has the tube-like fitting and the second housing has the fitting receiver. To connect the first and second connectors to each other, the first housing is inserted into the second housing. The latch serves to inhibit separation of the first and second housings from each other. Further, the plurality of ribs are formed to project from one of the exterior surface of the fitting and the interior surface of the fitting receiver. The plurality of recesses are formed on another one of the exterior surface of the fitting and the interior surface of the fitting receiver. Respectively fitting the ribs in the recesses firmly connects the first and second housings with each other so that rattling does not take place. Each of the ribs projects in a radial direction, and therefore vibrations in two directions perpendicular to each other when viewed from the connecting direction are simultaneously restrained with a single rib. Further, the ribs include two ribs which are disposed across from each other over the center portion of the fitting or fitting receiver, along a single line extending through the center line, when viewed from the connecting direction. With these two ribs disposed to oppose each other, the vibrations in two directions perpendicular to each other are effectively restrained with a minimum number of ribs. 
     Thus, the connected state of the both connectors is maintained while reducing an effect from vibration, with a simple structure. Therefore, even if the electric connecting device is subject to vibration, disconnection or a damage due to wear and tear is restrained. 
     Further, with the structure of the present invention, the housing is lightened with the minimum number of the ribs. Therefore, the entire connector is less likely given an adverse effect from vibration. This allows adoption of a latch whose resiliently-holding-force is relatively low. 
     The electric connecting device of the present invention may be adapted so that: the fitting is formed in the shape of a quadrangular tube; and the plural ribs or the plural recesses formed on the exterior surface of the fitting includes two to four ribs or two to four recesses which are respectively disposed at corner portions of the fitting. This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     The electric connecting device of the present invention may be adapted so that: the fitting is formed in a cylindrical shape; and the plural ribs or the plural recesses formed on the exterior surface of the fitting includes two to four ribs or two to four recesses which are disposed at an equal interval in a circumferential direction of the fitting when viewed from the connecting direction. This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     Further, to achieve the foregoing object, a latch-mountable connector housing of the present invention is for one of a pair of connectors connectable to each other, the housing including: a main body connectable to a counterpart connector of a counterpart housing, which supports a connector terminal electrically connectable to a counterpart terminal of the counterpart connector; and a latch which inhibits separation of the main body and the counterpart housing from each other. The main body has a fitting receiver for fitting therein a tube-like fitting formed on the counterpart housing, during a connected state in which the pair of connectors are connected to each other. When viewed from a connecting direction in which the pair of connectors connect to each other, the interior surface of the fitting receiver has (i) plural ribs each projecting in a radial direction of a center portion of the fitting or (ii) plural recesses each formed in the radial direction. The plural ribs or the plural recesses on the interior surface of the fitting receiver includes two ribs or two recesses disposed across from each other over the center portion, along a single line extending through the center line, when viewed from the connecting direction. With this, the connected state of the both connectors is maintained while reducing an effect from vibration, with a simple structure. 
     The latch-mountable connector housing of the present invention may be adapted so that: the fitting is formed in the shape of a quadrangular tube; and the plural ribs or the plural recesses formed on the interior surface of the fitting receiver includes two to four ribs or two to four recesses which are respectively disposed in positions corresponding to corner portions of the fitting, during the connected state. This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     The latch-mountable connector housing of the present invention may be adapted so that: the fitting is formed in a cylindrical shape; and the plural ribs or the plural recesses formed on the interior surface of the fitting receiver include two to four ribs or two to four recesses which are disposed at an equal interval in a circumferential direction of the fitting receiver when viewed from the connecting direction. This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     Further, to achieve the foregoing object, a latch-mountable connector housing of the present invention is for one of a pair of connectors connectable to each other, the housing including: a main body connectable to a counterpart connector of a counterpart housing, which supports a connector terminal electrically connectable to a counterpart terminal of the counterpart connector; and a latch which inhibits separation of the main body and the counterpart housing from each other. The main body is formed as a tube-like fitting to fit in a fitting receiver formed on the counterpart housing, during a connected state in which the pair of connectors are connected to each other. When viewed from a connecting direction in which the pair of connectors connect to each other, the exterior surface of the fitting has (i) plural ribs each projecting in a radial direction of a center portion of the fitting or (ii) plural recesses each formed in the radial direction. The plural ribs or the plural recesses on the exterior surface of the fitting includes two ribs or two recesses disposed across from each other over the center portion, along a single line extending through the center line, when viewed from the connecting direction. With this, the connected state of the both connectors is maintained while reducing an effect from vibration, with a simple structure. 
     The latch-mountable connector housing of the present invention may be adapted so that: the fitting is formed in the shape of a quadrangular tube; and the plural ribs or the plural recesses includes two to four ribs or two to four recesses which are respectively disposed at corner portions of the fitting. This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     The latch-mountable connector housing of the present invention may be adapted so that: the fitting is formed in a cylindrical shape; and the plural ribs or the plural recesses formed on the exterior surface of the fitting includes two to four ribs or two to four recesses which are disposed at an equal interval in a circumferential direction of the fitting when viewed from the connecting direction. This simplifies the shape of the housing and the positions of the ribs or the recesses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other and further objects, features and advantages of the invention will appear more fully from the following description taken in connection with the accompanying drawings in which: 
         FIG. 1  is a side view illustrating the entire structure of an electric connecting device of Embodiment 1, according to the present invention. 
         FIG. 2  is a cross sectional view of the electric connecting device of  FIG. 1 . 
         FIG. 3  is an exploded perspective view illustrating parts constituting the electric connecting device of  FIG. 1 . 
         FIG. 4  is a schematic view of the electric connecting device of  FIG. 1 , where  FIG. 4  ( a ) is a plane view,  FIG. 4  ( b ) is a front view, and  FIG. 4  ( c ) is a bottom view. 
         FIG. 5  is a schematic view of the electric connecting device of  FIG. 1 , where  FIG. 5  ( d ) is a right side view, and  FIG. 5  ( e ) is a back view. 
         FIG. 6  is a schematic view of a first housing of  FIG. 1 , where  FIG. 6(   a ) is a plane view,  FIG. 6(   b ) is a front view, and  FIG. 6(   c ) is a bottom view. 
         FIG. 7  is a schematic view of the first housing of  FIG. 1 ,  FIG. 7(   d ) is a right side view, and  FIG. 7(   e ) is a back view. 
         FIG. 8  is a schematic view of a second housing of  FIG. 1 , where  FIG. 8(   a ) is a plane view,  FIG. 8(   b ) is a front view, and  FIG. 8(   c ) is a bottom view. 
         FIG. 9  is a schematic view of the second housing of  FIG. 1 ,  FIG. 9(   d ) is a right side view, and  FIG. 9(   e ) is a back view. 
         FIG. 10  is a schematic view of a metal latch of  FIG. 1 , where  FIG. 10(   a ) is a plane view,  FIG. 10(   b ) is a front view, and  FIG. 10(   c ) is a right side view. 
         FIG. 11  is an enlarged front view of the first housing of  FIG. 1 . 
         FIG. 12  is a schematic view illustrating alternative forms of the first housing, where  FIG. 12(   a ) is a front view illustrating a first alternative form of the first housing, and  FIG. 12(   b ) is a front view illustrating a second alternative form of the first housing. 
         FIG. 13  is an exploded perspective view illustrating parts constituting an electric connecting device of Embodiment 2, according to the present invention. 
         FIG. 14  is an exploded perspective view illustrating parts constituting an electric connecting device of Embodiment 3, according to the present invention. 
         FIG. 15  is plane view illustrating an electric connecting device of Embodiment 4, according to the present invention. 
         FIG. 16  is a front view showing alternative forms of the metal latch, where  FIG. 16(   a ) illustrates a third alternative form and  FIG. 16(   b ) illustrates a fourth alternative form. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Overview 
     The following describes the entire structure of an electric connecting device of Embodiment 1, according to the present invention. Note that  FIG. 2  corresponds to a cross sectional view taken along line A-A′ of  FIG. 4(   a ). 
     An electric connecting device  1  is used as an equipment-use connector, which powers an impact acceleration sensor of an airbag system in an auto vehicle. This electric connecting device  1  includes: a first connector  2 , a second connector  4 , and a metal latch  5 . Connecting the second connector  4  to the first connector  2  which is fixed to not-illustrated equipment or the like establishes an electric connection between two first terminals  21  of the first connector  2  and two second terminals  41  of the second connector  4 . As a result, the equipment or the like and two wires  64  are electrically connected. 
     In the electric connecting device  1 , the metal latch  5  is attached to a second housing  42  of the second connector  4 . This metal latch  5  inhibits separation of the first housing  22  of the first connector  2  from the second housing  42  of the second connector  4 . Further, the first and second housings  22  and  42  are made of plastic (insulative material) in the present embodiment. 
     The electric connecting device  1  of the present embodiment is a bipolar electric connecting device. That is, the electric connecting device  1  has two first terminals  21  and two second connectors  4 . Note that the electric connecting device is not limited to the above, and the number of the first terminals (or the number of the second terminals) may be one, or three or more (see Embodiments 2 and 3 below). 
     Note that in the following description, a direction of connecting the pair of connectors (first and second connectors  2  and  4 ) to each other is referred to as “connecting direction” (see the direction indicated by Arrow G of  FIG. 1  and  FIG. 3 ). 
     (First Connector) 
     First, the first connector  2  is described. The first connector (counterpart connector)  2  has two first terminals (counterpart terminals)  21 , and a first housing (counterpart housing)  22 . These members are detailed below. Note that members within a range indicated by Arrow B of  FIG. 3  are members constituting the first connector  2 . 
     (First Housing) 
     The first housing  22  supports the two first terminals  21  and has a fitting  23  formed in the shape of a tube-like shape and a base  22   f . The fitting  23  fits in a later-mentioned fitting receiver  43  of the second connector  4 , while the first and second connectors  2  and  4  are connected to each other (hereinafter, connected state; see  FIG. 1 ). Further, in the present embodiment, the fitting  23  is formed in a quadrangular tube. More specifically, the fitting  23  is a tube whose cross section perpendicular to the connecting direction G is substantially a quadrangle (see  FIGS. 6(   b ) and  11 ). Further, the base  22   f  is fixed to a piece of equipment or the like. Note that the shape of the fitting is not limited and does not have to be a quadrangular tube, provided that the fitting has a tube-like shape (e.g. see Embodiment 2 below). 
     The fitting  23  has four ribs  24 , the details of which are provided below. When viewed from the connecting direction G, each of the four ribs  24  is formed so as to project from the exterior surface  23   s  of the fitting  23  in a radial direction of a center portion  23   c  of the fitting  23  (see directions of single-dotted lines in  FIG. 11 ), as illustrated in  FIGS. 3 ,  6 ( b ), and  11 . Further, the four ribs  24  are formed on the root (an end of the fitting  23  closer to the base  22   f ) of the fitting  23 , as illustrated in  FIGS. 3 ,  6 ( a ),  6 ( c ), and  7 ( d ). Note that the radial directions indicated by the chain line (the directions in which the ribs project) in  FIG. 11  are solely to serve as examples selected from countless number of radial directions, and “radial direction(s)” in this specification is not limited to these directions. 
     The following further details the ribs  24 . The four ribs  24 , which are formed on the exterior surface  23   s  of the fitting  23  in the shape of a quadrangular tube, are respectively positioned at four corner portions of the fitting  23  (see  FIGS. 3 ,  6 ( b ), and  11 ). Further, when viewed from the connecting direction, two out of the four ribs  24  on the exterior surface  23   s  of the fitting  23  are positioned across from each other over the center portion  23   c  of the fitting  23 , along a single line extending through the center portion  23   c . In the example presented in  FIG. 11 , ribs  24   a  and  24   d  (or ribs  24   b  and  24   c ) are those two ribs  24  positioned across from each other over the center portion  23   c , along a single line extending through the center portion  23   c.    
     For example, the two ribs positioned across from each other over the center portion, along a single line extending through the center portion may be respectively disposed at both ends of a diagonal line of the fitting in the front view. That is, the two ribs may be respectively disposed at two positions where a single line connecting the two positions via the center portion is the longest. The arrangement of the ribs  24  in the present embodiment is based on the perspective thus described. Note that the positions of the ribs are not limited to this. 
     The number of ribs  24  is not limited to four, provided that the ribs  24  includes at least two ribs  24  (ribs  24   a  and  24   d  or ribs  24   b  and  24   c  in the present embodiment) opposing each other (see first and second alternative forms below). Further, two or three ribs may be disposed at corner portions on the exterior surface of the fitting formed in the shape of a quadrangular tube (see first and second alternative forms below). 
     Further, when viewed from the connecting direction, the exterior surface  23   s  of the fitting  23  is provided with four supplementary recesses  25 . These four supplementary recesses  25  are formed so as to dent towards the center portion  23   c  of the fitting  23 , in a radial direction of the center portion  23   c  (see  FIGS. 3 ,  6 ( b ), and  11 ). Further, the four supplementary recesses  25  are formed at the leading end of the exterior surface  23   s  of the fitting  23  (see  FIGS. 3 ,  6 ( a ), and  7 ( d )). 
     In the present embodiment, the expression “in a radial direction” means in a radial direction about the center portion  23   c . The center portion  23   c  is a single point in the present embodiment; however, the center portion  23   c  may be a group of two or more points whose respective positions are different from one another. Further, the center portion may be a region having a certain dimension. 
     Further, where the connecting direction is a direction of connecting the second housing  42  to the first housing  22 , an end at the back side of the first housing  22  relative to the connecting direction (K side in  FIG. 3 ; the side of the first housing  22  opposite to the base  22   f ) is provided with a pair of connection sloping surface  22   s  for spreading a pair of support portions  51  (see  FIGS. 3 ,  6 ( b ), and  7 ( b )). 
     Further, on both side portions of the first housing  22 , projections  22   x  are formed respectively (see  FIGS. 3 ,  6 , and  7 ( d )). At the front side of each projection  22   x  relative to the connecting direction (L side on  FIG. 6(   c ); the side of the projection  22   x  closer to the base  22   f ) is a sloping surface serving as a support receiver  26  (see  FIGS. 3 ,  6 ( c ), and  7 ( d )). More specifically, the sloping surface serving as the support receiver  26  is such that the height (projection amount) thereof from the exterior surface  23   s  is gradually reduced from the back side to the front side of the support receiver  26  in the connecting direction G (i.e., towards L side on  FIG. 6(   c )). During the connected state, support portions  51  of the metal latch  5  are respectively latched on and closely attached to the support receivers  26 . In the present embodiment, L 2  is the distance between the leading ends of the projections  22   x  (see  FIG. 6(   c )), and L 3  is the distance between later-mentioned portions of the support receivers  26  where the support portions  51  contact during the connected state (see  FIG. 6(   a )). 
     In addition to the two projections  22   x  on the both side portions of the fitting  23 , the fitting  23  is provided with two guide projections  22   w  (see  FIGS. 3 ,  6 , and  7 ). The guide projections  22   w  on both side portions of the fitting  23  are formed on the exterior surface  23   s , and linearly extend in the connecting direction. Further, on each side of the fitting  23 , the projection  22   x  and guide projection  22   w  are arranged in the connecting direction. The projection  22   x  and the guide projection  22   w  are arranged in a non-continuous manner so as to form a groove between these projections. In the groove is formed a side recess  27  (see  FIG. 7(   d )). 
     At the bottom of the fitting  23  is formed a guide projection  22   v  for preventing miss-fitting (see  FIGS. 3 ,  6 ( b ), and  7 ( d )). The guide projection  22   v  is also formed so as to linearly extend in the connecting direction. 
     Further, inside the fitting  23  is formed an internal space  23   v  (see  FIGS. 3 ,  6 ( b ), and  11 ). At the front side of the internal space  23   v , a T-shape fitting recess  22   m  is formed (see  FIGS. 2 and 6(   b )). Further, the first housing  22  has two insertion holes  22   h  in which two first terminals  21  are respectively inserted (see  FIGS. 2 ,  6 ( b ), and  7 ( e )). Note that the  FIG. 11  omits illustration of the fitting recess  22   m  and the two insertion holes  22   h.    
     (First Terminal) 
     The two first terminals  21  are electrically connectable to the two second terminals  41  during the connected state, respectively. Each of the two first terminals  21  is formed in a rod-like shape (see  FIGS. 2 and 3 ). On the leading end of each first terminal  21  is formed a contact portion  21   s  which contacts the second terminal  41 . The connected state of the first and second terminals  21  and  41  is detailed hereinbelow in the description of the second terminals  41 . 
     (Second Connector) 
     Next described is the second connector  4 . The second connector (connector)  4  is electrically connectable to the first connector  2 , and has two second terminals (connector terminals)  41 , a second housing (connector housing)  42 , a seal ring  62 , and a retainer  63 . Each of these members is detailed below. Note that members within a range indicated by Arrow C of  FIG. 3 , except for the metal latch  5 , are members constituting the second connector  4 . 
     (Second Housing) 
     The second housing  42  supports the two second terminals  41 , and includes: a main body  42   b  connectable to the first housing  22 ; a cover  47 ; and a flexible jointing portion  42   c . The main body  42   b  is used for supporting the two second terminals  41 . The main body  42   b  of the second housing has a fitting receiver  43  for fitting therein the fitting  23  during the connected state (see  FIGS. 2 , and  9 ( e )). More specifically, the main body  42   b  is formed in the shape of a quadrangular tube (see  FIG. 9(   e )), and the fitting receiver  43  is formed inside the quadrangular tube. Here, the fitting receiver  43  has a space formed inside the main body  42   b  and an interior surface  43   s  surrounding the space. 
     In the interior surface  43   s  are formed four recesses  44  (see  FIG. 9(   e )). During the connected state, the four ribs  24  of the fitting  23  fit in the below-detailed four recesses  44 , respectively. 
     When viewed from the connecting direction, the interior surface  43   s  of the fitting receiver  43  has four recesses  44  each of which is dented in a radial direction of the center portion of the fitting receiver  43  (see  FIG. 9(   e )). Further, the four recesses  44  are formed at the front side (opening side) of the fitting receiver  43 . 
     The recesses  44  are further detailed below. In the main body  42   b  formed in the shape of quadrangular tube, the four recesses  44  are disposed in positions corresponding to the corner portions of the fitting  23  during the connected state (see  FIG. 9(   e )). Further, when viewed from the connecting direction, two out of the four recesses  44  on the interior surface  43   s  are positioned across from each other over the center portion of the fitting receiver  43 , along a single line extending through the center portion. 
     The interior surface of the fitting receiver formed in the shape of a quadrangular tube may have at its corner portions two or three recesses  44 , and the number of the recesses is not limited to four. 
     Further, when viewed from the connecting direction, the interior surface  43   s  of the fitting receiver  43  has four supplementary ribs  45  each projecting in a radial direction of the center portion of the fitting receiver  43  (see  FIG. 9(   e )). Further, the four supplementary ribs  45  are formed at the back side of the interior surface  43   s  of the fitting receiver  43 . These four supplementary ribs  45  fit in the four supplementary recesses  25  formed on the fitting  23 , during the connected state. 
     Further, inside the second housing  42  are formed two guide grooves  42   x  which linearly extend in the connecting direction (see  FIG. 9(   e )). The two guide grooves  42   x  are grooves for fitting therein two projections  22   x  and two guide projections  22   w  of the first housing  22  during the connecting operation. Further, inside the second housing  42  is formed a guide groove  42   v  which linearly extends in the connecting direction (see  FIG. 9(   e )). 
     The guide groove  42   v  is a groove in which the guide projection  22   v  of the first housing  22  fit in during the connecting operation. 
     To smoothen the connection of the first and second connectors  2  and  4 , the width of the guide groove  42   v  is relatively wider than that of the guide projection  22   v . That is, the guide projection  22   v  and the guide groove  42   v  have therebetween a play. The same goes to the guide grooves  42   x , and the width of each guide groove  42   x  is relatively wider than each projection  22   x  or each guide projection  22   w.    
     The second housing  42  has two grooves  42   d . To these grooves  42   d  is attached the metal latch  5 . Specifically, two side walls  46  are formed on both side portions of the main body  42   b . The grooves  42   d  are formed on the two side walls  46 , respectively. Here, the depth of each groove  42   d  on either one of the two side walls  46  is greater than the thickness of the metal latch  5  (see W 1  of  FIG. 10(   c )). Therefore, in the electric connecting device  1 , the outermost portion of the metal latch  5  is in a position deeper than the surface of the side wall  46 , as illustrated in  FIG. 4  ( a ). This keeps the metal latch  5  from being touched by a finger. Note that the two side walls  46  are part of the main body  42   b , in the present embodiment. 
     In the main body  42   b  of the second housing  42 , each groove  42   d  has an unlocking sloping surface  42   p  (see  FIGS. 1 ,  3 ,  5 ( b ), and  9 ( d )). The unlocking sloping surface  42   p  is formed at the front side (lower side in  FIG. 1 ) of the groove  42   b  relative to a direction of mounting the metal latch  5  (i.e., in the direction of Arrow H in  FIGS. 1 ,  3 , or the like; hereinafter, mounting direction). 
     Further, in the present embodiment, each of the two side walls  46  has a projecting leading part  46   t  which projects in the opposite direction to the mounting direction (upward in  FIG. 8(   b )), beyond the top surface of the middle portion  42   y  of the main body  42   b  (see  FIG. 8(   b )). Note that the shape of each sidewall is not limited to this, and the projecting leading part  46   t  does not necessarily have to be formed. Further, each of the grooves may be formed in a position other than the side wall. 
     The second housing  42  has a cover  47  for covering the metal latch  5 . The cover  47  is formed in a plate like shape, and the cover  47  and the main body  42   b  are formed in one piece via the flexible jointing portion  42   c  ( FIGS. 1 ,  2 ,  3 , or the like). Further, the cover  47  is formed in one piece with the main body  42   b  so that only one end of the cover  47  is fixed. 
     The cover  47 , the main body  42   b , and the projecting leading part  46   t  form a space  42   s  for the metal latch  5 , which accommodates therein a middle support portion  53  of the metal latch  5  (see  FIGS. 2 and 4(   b ), and  8 ( b )). Further, the cover  47  has a cover groove  47   d  on a surface thereof facing the main body  42   b  (see  FIGS. 2 and 3) . While the cover  47  is closed as shown in  FIGS. 1 ,  2 ,  4 , and  5 , the middle support portion  53  is accommodated in the cover groove  47   d  (see  FIG. 2 ). the cover  47  is inclined from the main body  42   b  as illustrated in  FIG. 3 , at the time of assembling the second connector  4 . Bending the cover  47  at the flexible jointing portion  42   c , while the metal latch  5  is mounted to the second housing  42 , covers the metal latch  5  (covering state). 
     During the covering state, the metal latch  5  fits in the cover groove  47   d . Therefore, an increase in the size of the second connector  4  in the longitudinal direction of  FIGS. 1 and 2  is prevented, and downsizing of the connector in the longitudinal direction is possible. Further, fitting the metal latch  5  in the cover groove  47   d  stabilizes the positional relationship of the cover  47  to the metal latch  5 . Therefore, the metal latch  5  is reliably pressed in with a use of the cover  47 , in a later-mentioned unlocking operation. Note that the cover groove  47   d  does not necessarily have to be formed. 
     Further, the cover  47  is disposed at the middle portion  42   y  (see  FIG. 3 ) sandwiched between the pair of the side walls  46  of the main body  42   b . That is the cover  47  is disposed in a position of the main body  42   b , where no groove  42   d  is formed. Note that the present embodiment deals with a case where no groove  42   d  is formed in the middle portion  42   y  of the main body  42   b . However, a groove may be formed in the middle portion. 
     Further, on the both side portions at the leading end of the cover  47 , two cover projections  47   t  are formed (see  FIG. 3 ). On the other hand, a projection receiver  42   t  is formed at the back side (K side on  FIG. 3 ) of each side wall  46  relative to the connecting direction G (see  FIG. 3 ). During the covering state, the two cover projections  47   t  are respectively latched on the two projection receiver  42   t  (see  FIG. 8  ( b )). Thus, the cover  47  is inhibited from returning to the inclined state, and the covering state is maintained. 
     Further, in the main body  42   b  is formed a terminal supporter  42   k  (see  FIGS. 2 and 9(   e )). The terminal supporter  42   k  supports two second terminals  41 , along with a later-mentioned retainer  63 . During the connected state, the terminal supporter  42   k  and the two second terminals  41  are inserted into the internal space  23   v  of the first housing  22 . At the leading end of the terminal supporter  42   k  is formed a T-shaped fitting projection  42   m  (see  FIGS. 2 and 9(   e )). During the connected state, the fitting projection  42   m  is inserted into the fitting recess  22   m  of the first housing  22  (see  FIG. 2) . 
     Further, at the back side of the second housing  42  in the connecting direction are formed two insertion holes  42   h  into which the two second terminals  41  are respectively inserted ( FIG. 2 ,  8 ( b ), and  9 ( a )). At the bottom part of the second housing  42  is formed an insertion hole  42   j  (see  FIG. 8(   c )). Through the insertion hole  42   j , the later-mentioned retainer  63  is mounted at the time of assembling the second connector  4 . 
     (Second Terminal) 
     The two second terminals  41  are electrically connectable to the two first terminals  21 , respectively. Each second terminal  41  is formed in the shape of a quadrangular tube (see  FIGS. 2 and 3 ). More specifically, as illustrated in  FIG. 2 , each of the second terminals  41  has therein a plate contact portion  41   s  which contacts the contact portion  21   s  of the first terminal  21 . The contact portion  41   s  is formed in one piece with the outer wall of the quadrangular tube shape of each second terminal  41 . When the second terminal  41  and the first terminal  21  are connected to each other, the contact portion  41   s  is resiliently bent at its root portion, contacting the contact portion  21   s  in such a manner as to hold down the contact portion  21   s . Further, each second terminal  41  is connected to an electric wire  64 . 
     Further, in the present embodiment, a seal cover  65  is attached to each electric wire  64  ( FIG. 2  and  FIG. 3 ). The seal cover  65  is inserted into the insertion hole  42   h  of the second housing  42 , thereby ensuring the air tightness and water tightness of the second connector  4 . 
     (Metal Latch) 
     Next, the metal latch  5  is described. The metal latch  5  is a metal member for inhibiting separation of the first and second housings  22  and  42  from each other. Such a metal latch  5  is formed by curving a single rod-like member. More specifically, the metal latch  5  is mounted to the main body  42   b  of the second housing  42 , and resiliently sandwiches the first housing  22  and supports the same so as to inhibit the separation of the main body  42   b  from the first housing  22 . 
     The metal latch  5  is formed so as to include: the linearly extending middle support portion  53 ; a pair of hanging portions  54  which respectively extend from the both ends of the middle support portion  53  perpendicularly to the middle support portion  53 ; a pair of sloping portions  56  respectively extending inwardly from the pair of hanging portions  54 ; the pair of support portions  51  which are curved portions respectively formed at the ends of the sloping portions  56 ; a pair of tip portions  55  formed so as to outwardly extend from the ends of the sloping portions  51  (see  FIG. 10(   b )). In the present embodiment, L 1  is a distance between the pair of support portions  51  when the metal latch  5  is not mounted from the second connector  4 ; i.e., while the metal latch  5  is free of load (see  FIG. 10(   b )). L 3  (see  FIG. 6(   a )) is greater than L 1 , and L 2  is greater than L 3 . 
     That is, L 1 , L 2 , and L 3  satisfies the following relation:
 
L1&lt;L3&lt;L2  (1)
 
     This relation of L 2  being greater than L 1  and L 3  being smaller than L 2  realizes a clicking feel when the metal latch  5  resiliently recovers its original state in a connecting operation. Further, since L 1  is greater than L 3 , the force to restore the original state of the metal latch  5  causes the pair of support portions  51  to sandwich and support the support receiver  26 , during the connected state. Note that the above relation among L 1 , L 2 , and L 3  is solely to serve as an example, and the relation among L 1 , L 2 , and L 3  is not limited to this. 
     While the second connector  4  is connected to the first connector  2  (during the connected state), the metal latch  5  sandwiches the first housing  22  between the pair of the support portions  51 . Thus, the support portions  51  are respectively latched on the support receiver  26  formed on the first housing  22 . In other words, the projections  22   x , during the connected state, inhibits the metal latch  5  from moving to separate in the opposite direction to the connecting direction. 
     The latch main portion  52  of the metal latch  5  surrounded by the broken line in  FIG. 10(   b ) has a C-shape whose curvature continuously varies in a single plane (i.e. two-dimensionally curved) (see  FIGS. 10(   b ),  10 ( a ), and  10 ( c )). The latch main portion  52  includes the middle portion between the pair of the support portions  51 . Specifically, the latch main portion  52  includes the middle support portion  53 , the pair of hanging portions  54 , and the pair of sloping portions  56 . Note that the latch main portion of the metal latch may have a U-shape whose curvature continuously varies in a single plane. 
     Further, the latch main portion  52  of the metal latch  5  has a C-shape whose curvature continuously varies in a single plane, and varying the diameter of the metal latch  5  allows setting of an intended resiliently-holding-force. 
     Further, the metal latch  5  is mounted in a direction perpendicular to the connecting direction along a plane (plane J in  FIG. 3 ) perpendicular to the connecting direction. In short, the mounting direction H is parallel to the plane J. 
     Further, in the electric connecting device  1 , the diameter of the metal latch  5  (W 1  of  FIG. 10(   c )) is not more than the width of the groove  42   d  (W 2  of  FIG. 9(   d )). That is, the metal latch  5  and the second connector  4  are formed to satisfy the relation of: W 1 ≦W 2 . 
     For example, the maximum tolerable gravitational acceleration (the maximum gravitational acceleration which ensures that the connected state of the connectors is maintained) and W 1  of the metal latch is as follows: 
     W 1 : 1.0 [mm] Maximum tolerable gravitational acceleration: 300 [G] 
     W 1 : 1.2 [mm] Maximum tolerable gravitational acceleration: 1000 [G] 
     Thus, the maximum gravitational acceleration tolerated by the metal latch is adjusted by varying W 1  without modification of the entire shape. For example, suppose W 1  of the metal latch is originally 1.0 mm. In this case, setting the width W 2  of the groove to 1.2 mm allows mounting of a different metal latch which tolerates the maximum gravitational acceleration of 1000 G despite variation in the connector installing environment or the like. 
     In the present embodiment, the metal latch  5  has a pair of support portions  51 . However, the metal latch may have two or more pairs of support portions. Further, the metal latch is not particularly limited to the one described in the present embodiment, provided that the metal latch is capable of inhibiting separation of the first and second housings  22  and  42 . For example, the latch main portion of the metal latch does not have to have a shape whose curvature continuously varies in a single plane, and may have a three-dimensional structure. Further, the shape of the latch main portion is not limited to a C-shape or a U-shape. For example, the shape of the latch main portion may be a V-shape, an H-shape, or the like. Further, the metal latch may be, for example, a member which locks the housing by latching from inside the housing (see Embodiment 4 below). 
     (Others) 
     The second connector  4  has a seal ring  62  and a retainer  63  in addition to the above mentioned members (see  FIG. 3 ). The seal ring  62  is a member which ensures the air tightness and water tightness, whereas the retainer  63  is a member which supports the two second terminals  41 . 
     (Metal-Latch-Mountable Connector Housing) 
     Next, a metal-latch-mountable connector housing  3  is described. The metal-latch-mountable connector housing  3  includes the main body  42   b  of the second housing  42 , and a metal latch  5  (see  FIGS. 1 ,  2 , and  3 ). In the present embodiment, the metal-latch-mountable connector housing  3  is a combination of the second housing  42  and a metal latch  5 . Note that the metal-latch-mountable connector housing  3  is not particularly limited, provided that the metal-latch-mountable connector housing  3  is used as one of a pair of connectors connectable to each other. For example, the metal-latch-mountable connector housing  3  may be a combination of the metal latch and the first housing of the present embodiment (see Embodiment 4 below). 
     (Metal-Latch-Mountable Connector) 
     Next, a metal-latch-mountable connector  7  is described below. The metal-latch-mountable connector  7  includes: two second terminals  41 , the second housing  42 , and the metal latch  5  (see  FIGS. 1 and 2 ). That is, the metal-latch-mountable connector  7  includes a metal-latch-mountable connector housing  3  and two second terminals  41 . 
     (Connecting Operation) 
     Next, the connecting operation of the electric connecting device  1  is described. At the beginning, the metal latch  5  is mounted to the second connector  4 , and the cover  47  is in the covering state. Then, at the time of connecting the electric connecting device  1 , the second connector  4  with the metal latch  5  being attached thereto is connected to the first connector  2 . Note that, at the time of connecting the electric connecting device  1 , the connecting operation is performed by holding the two side walls  46  of the second connector  4 . The second housing  42  has the cover  47 , and therefore, the clicking feel at the time of connecting is not lost even if a finger touches the cover  47  during the connecting operation. 
     First, the following describes the state at the beginning of connecting the first and second connectors  2  and  4 . At the beginning, the tip portions of the metal latch  5  respectively contact the pair of connection sloping surfaces  22   s , with the movement of connecting the electric connecting device  1  (advancing of the second connector  4 ). Further advancing the second connector  4  causes the pair of support portions  51  to respectively contact the pair of connection sloping surfaces  22   s , thereby widening the gap between the pair of the support portions  51 . As a result, the second connector  4  smoothly moves towards the first connector  2  without stopping. 
     Further, at the connection starting time, the second connector  4  is connected to the first connector  2  in such a manner that the guide projection  22   v  fits in the guide groove  42   v . Thus, miss-fitting (fitting two connectors upside down) is prevented. 
     Next, the state during the connecting operation is described. During the connecting operation, the guide projection  22   v  of the first housing  22  fit in the guide groove  42   v  of the second housing  42 . Further, the two projections  22   x  of the first housing  22  and the two guide projections  22   w  respectively fit in the two guide grooves  42   x  of the second housing  42 . Thus, during the connecting operation, the second connector  4  is pressed towards the first connector  2  along these guide grooves; i.e., in the connecting direction. 
     Further, with the movement of the electric connecting device  1 , the support portions  51  advances while contacting the connection sloping surfaces  22   s  and the projections  22   x . This resiliently deforms the metal latch  5 , and increases the distance between the pair of the support portions  51 . Here, while the pair of support portions  51  are at the leading end of the projections  22   x , the distance between the pair of support portions  51  is the maximum (L 2 ). Further pressing the second connector  4  from this state moves the pair of support portions  51  towards the pair of support receivers  26  which are sloping surfaces. At this time, the metal latch  5  having resiliently deformed tries to restore its original shape. Therefore, the pair of support portions  51  move beyond the pair of projections  22   x , and move toward the center portion  23   c  along the pair of support receivers  26  (sloping surfaces). 
     More specifically, (A) the distance (Ls) between the pair of supporting portions  51  immediately before the connection completed state is greater than L 1  (see  FIG. 10(   b )), and (B) a distance (Le) between the pair of support portions  51  during the connection completed state the connection is completed is smaller than Ls. That is, the following relation is established.
 
L1&lt;Ls  (2)
 
Le&lt;Ls  (3)
 
     Thus, the metal latch  5  once having been deformed resiliently restores its original state, yielding the clicking feel upon completion of the connection. In particularly, the following relation is established in the present embodiment.
 
Ls=L2  (4)
 
Le=L3  (5)
 
     As hereinabove mentioned, after the metal latch  5  is deformed in the connection operation of the electric connecting device  1 , a clicking feel is given when the metal latch  5  once having been deformed resiliently restores its original state. That is, when the support portions  51  go over the projections  22   x  formed in the shape of a mountain, a movement of the metal latch  5  to resiliently restore its original state is enabled. This yields the clicking feel which allows an operator to confirm that the pair of connectors are properly connected. 
     Next, the following describes the connected state in which the first and second connectors  2  and  4  are connected to each other. During this state, the fitting  23  is fit in the fitting receiver  43 , and the terminal supporters  42   k  and the two second terminals  41  are inserted into the internal space  23   v  of the fitting  23 . The pair of the connectors are connected to each other, and the first and second terminals  21  and  41  are electrically connected. 
     Further, during the connected state, the fitting projection  42   m  is inserted into the fitting recess  22   m  of the first housing  22 . Then, the four ribs  24  of the fitting  23  fit in the four recesses  44 , and the four supplementary ribs  45  fit in the four supplementary recesses  25  formed on the fitting  23 . 
     Further, during the connected state, the support portions  51  of the metal latch  5  sandwich therebetween the first housing  22 , and the support portions  51  are latched on the support receivers  26  formed on the first housing  22 . Then, the metal latch  5  resiliently sandwiching and supporting the first housing  22  inhibits separation of the pair of connectors. This state is referred to as locked state. 
     During the connected state, the support portions  51  of the metal latch  5  are closely attached to and latched on the sloping surfaces of the support receivers  26 . Further, the pair of support portions  51  are latched on the support receivers  26 , between the exterior surface  23   s  and the vertex of the projections  22   x . Then, the metal latch  5  is latched at the front side of the projections  22   x  relative to the connecting direction. 
     Thus, the metal latch  5  is prevented from separating towards the back side of the first housing  22  relative to the connecting direction. 
     As described, while the metal latch  5  is mounted to the second connector  4 , and while the first and second connectors  2  and  4  are in the connected state, the metal latch  5  is at a mounting position (a position in which the pair of support portions  51  are latched on the pair of support receivers  26 ). The state in which the metal latch  5  is at the mounting position during the connected state is hereinafter referred to as “connection completed state” (see  FIGS. 1 ,  2 ,  4 , and  5 ). 
     Next, the following describes a separating operation of the first and second connectors  2  and  4 . For the separating operation, the locked state of the metal latch  5  needs to be released. In the electric connecting device  1 , pressing the cover  47  with a finger or the like towards the main body  42   b  while the metal latch  5  is in the mounting position further presses the metal latch  5  in the mounting direction. Then, the unlocking sloping surfaces  42   p  and the pair of the support portions  51  respectively contact each other, thus widening the gap between the pair of support portions  51  (unlocked state). The electric connecting device  1  easily allows this unlocking operation (operation of unlocking the metal latch  5 ). 
     The present embodiment deals with a case where each support receiver  26  is formed as a sloping surface of the projection  22   x . However, the support receiver is not limited to the present embodiment. The support receiver may be formed perpendicularly to the surface of the exterior surface  23   s , instead of forming the same as a sloping surface. Further, instead of realizing the support receiver with the front side of the projection, the housing main body may be provided with a groove serving as a support receiver. The clicking feel upon completion of connection is achieved in either cases, by structuring the support receiver to satisfy the above formulas (2) and (3). 
     (Effects) 
     Next, the following describes effects achieved by the electric connecting device  1  and the metal-latch-mountable connector housing  3  of the present embodiment. The electric connecting device  1  of the present embodiment includes: the first connector  2  having two first terminals  21  and the first housing  22  supporting the first terminals  21 ; the second connector  4  including two second terminals  41  electrically connectable to the two first terminals  21 , respectively, and the second housing  42  supporting the two second terminals  41 ; and the metal latch  5  which inhibits separation of the first and second housings  22  and  42  from each other. The first housing  22  has the tube-like fitting  23 , and the second housing  42  has the fitting receiver  43  for fitting therein the fitting  23  during the connected state in which the first and second connectors  2  and  4  are connected to each other. When viewed from the connecting direction in which the first connector  2  connects to the second connector  4 , the exterior surface  23   s  of the fitting  23  has four ribs  24  each projecting in a radial direction of the center portion  23   c  of the fitting  23 . The interior surface  43   s  of the fitting receiver  43  on the other hand has four recesses  44  for respectively fitting therein the four ribs  24  during the connected state. The four ribs  24 , when viewed from the connecting direction, includes two ribs  24  disposed across from each other over the center portion  23   c , along a single line extending through the center portion  23   c.    
     In this structure, the first housing  22  has the tube-like fitting  23  and the second housing  42  has the fitting receiver  43 . To connect the first and second connectors  2  and  4  to each other, the first housing  22  is inserted into the second housing  42 . The metal latch  5  serves to inhibit separation of the first and second housings  22  and  42  from each other. Further, the four ribs  24  are formed to project from the exterior surface  23   s  of the fitting  23 , and the four recesses  44  are formed on the interior surface  43   s  of the fitting receiver  43 . Respectively fitting the ribs  24  in the recesses  44  firmly connects the first and second housings  22  and  42  to each other so that rattling does not take place. Each of the four ribs  24  projects in a radial direction, and therefore vibrations in two directions perpendicular to each other (e.g., shaking in the longitudinal and horizontal directions of  FIG. 11 ) when viewed from the connecting direction are simultaneously restrained with a single rib. Further, when viewed from the connecting direction, the four ribs  24  includes two ribs  24  disposed in positions opposing each other across the center portion  23   c  of the fitting  23 , along a single line extending through the center portion  23   c . With these two ribs  24  disposed to oppose each other, the vibrations in two directions perpendicular to each other are effectively restrained with a minimum number of ribs. 
     Thus, the connected state of the both connectors (first and second connectors  2  and  4 ) is maintained while reducing an effect from vibration, with a simple structure. Therefore, even if the electric connecting device is subject to vibration, disconnection or a damage due to wear and tear is restrained. 
     Further, with the structure of the present embodiment, the housing is lightened with the minimum number of the ribs. Therefore, the entire connector is less likely given an adverse effect from vibration. This allows adoption of a metal latch whose resiliently-holding-force is relatively low. 
     The electric connecting device  1  of the present embodiment is adapted so that: the fitting  23  is formed in the shape of a quadrangular tube; and the four ribs  24  formed on the exterior surface  23   s  of the fitting  23  are respectively disposed at corner portions of the fitting  23 . This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     Further, a metal-latch-mountable connector housing  3  of the present embodiment is used as one of a pair of connectors connectable to each other, and includes: the main body  42   b  connectable to the first connector  2  of the first housing  22 , which supports the two second terminals  41  to be respectively connected to the two first terminals  21  of the first connector  2 ; and a metal latch  5  which inhibits separation of the main body  42   b  and the first housing  22  from each other. The main body  42   b  has a fitting receiver  43  for fitting therein a tube-like fitting  23  formed on the first housing  22 , during a connected state in which the pair of connectors are connected to each other. When viewed from a connecting direction in which the pair of connectors connect to each other, the interior surface  43   s  of the fitting receiver  43  has plural ribs  24  each projecting in a radial direction of a center portion  23   c  of the fitting  23 . The plural ribs  24  on the interior surface  43   s  of the fitting receiver  43  includes two ribs disposed across from each other over the center portion  23   c , along a single line extending through the center line  23   c , when viewed from the connecting direction. With this, the connected state of the both connectors is maintained while reducing an effect from vibration, with a simple structure. 
     The metal-latch-mountable connector housing  3  of the present embodiment is adapted so that: the fitting  23  is formed in the shape of a quadrangular tube; and the four recesses  44  formed on the interior surface  43   s  of the fitting receiver  43  are respectively disposed in positions corresponding to corner portions of the fitting  23 , during the connected state. This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     The advantageous effects of the electric connecting device  1  and the metal-latch-mountable connector housing  3  of the present embodiment are particularly remarkable when used under an environment where the installation direction of the first housing and a direction of the connector-affecting vibration are determined to a certain extent. For example, suppose that the first connector is installed as illustrated in  FIG. 11 , and that the main directions of the vibration affecting the first connector are the longitudinal and horizontal directions of  FIG. 11 . In such a case, effects from vibrations in the longitudinal and horizontal directions of  FIG. 11  are efficiently restrained by disposing a rib at each corner position (upper left, upper right, lower left, and lower right in front view) of the fitting as illustrated in  FIG. 11 . Note that the electric connecting device of the present invention is usable even if the direction of disposing the first housing and the direction of vibration are not certain. 
     Further, as mentioned above, there is a play between the guide groove  42   v  and the guide projection  22   v , and between (i) the guide groove  42   x  and (ii) the projection  22   x  and the guide projection  22   w . However, the ribs  24 , supplementary ribs  45 , recesses  44 , and supplementary recesses  25  are formed, and by closely attaching these parts with little gap therebetween, the first and second connectors  2  and  4  during the connected state are hardly affected by the vibration. 
     Further, in Embodiment 1, the ribs  24  and the supplementary recesses  25  are formed on the first housing  22 , and supplementary ribs  45  and the supplementary recesses  44  are formed on the second housing  42 . That is, in Embodiment 1, ribs and recesses are formed on both of the first and second housings  22  and  42 . The present invention however is not limited to such a structure, and the supplementary ribs and supplementary recesses do not have to be formed. 
     Further, in Embodiment 1, the plural ribs  24  are formed on the exterior surface  23   s  of the fitting  23 , and the plural recesses  44  are formed on the interior surface  43   s  of the fitting receiver  43 . It is however possible to form plural ribs on the interior surface of the fitting receiver, and plural recesses on the exterior surface of the fitting, as opposed to Embodiment 1. In this case, the plural ribs are formed to project in the radial direction of the center portion of the fitting receiver, and the plural ribs on the interior surface of the fitting receiver includes two ribs disposed across from each other over the center portion of the fitting receiver, along a single line extending through the center portion. 
     (Alternative Forms) 
     Next, the following describes alternative forms of the electric connecting device of Embodiment 1 according to the present invention, mainly focusing on the difference from the above embodiment. Note that members similar to those of the above embodiment are given the same reference symbols in the drawings, and no further description therefor is provided hereinbelow.  FIG. 12  is a schematic view illustrating an alternative form of the first housing, where  FIG. 12(   a ) is a front view of a first alternative form of the first housing, and (b) is a front view of a second alternative form of the first housing. 
     The above embodiment deals with a case where the four ribs  24  are formed on the exterior surface  23   s  of the fitting  23 , and four recesses are formed on the interior surface  43   s  of the fitting receiver  43 . The respective numbers of the ribs and recesses are not limited to four, provided that the numbers of ribs and recesses are more than one. Specifically, as in the fitting  123  of the first alternative form, the number of ribs  24  may be only two. Alternatively, the number of ribs  24  may be three as in the fitting  223  of the second alternative form. In the first and second alternative forms, the plural ribs formed on the exterior surface of the fitting includes two ribs  24   a  and  24   d  (see  FIG. 11 ) which are disposed across from each other over the center portion  23   c , along a single line extending through the center portion  23   c.    
     Embodiment 2 
     Next, the electric connecting device of Embodiment 2, according to the present invention is described below, mainly focusing on the difference from the above embodiment. Note that the members that are similar to those of the above embodiment are given the same reference symbols and no further explanation is provided hereinbelow. Further, in the present embodiment, members and parts given the reference symbols  303 ,  305 ,  321 ,  321   s ,  322 ,  322   f ,  322   s ,  322   v ,  322   w ,  322   x ,  323 ,  323   s ,  324 ,  325 ,  326 ,  341 ,  342 ,  342   h ,  342   t ,  346 ,  347 ,  347   d ,  347   t ,  364 , and  365  respectively correspond to the members and parts of the foregoing embodiment given the reference symbols  3 ,  5 ,  21 ,  21   s ,  22 ,  22   f ,  22   s ,  22   v ,  22   w ,  22   x ,  23 ,  23   s ,  24 ,  25 ,  26 ,  41 ,  42 ,  42   h ,  42   t ,  46 ,  47 ,  47   d ,  47   t ,  64 , and  65 . The respective functions of these members and parts are the same as the foregoing embodiment.  FIG. 13  is an exploded perspective view illustrating members constituting an electric connecting device of Embodiment 2, according to the present invention. 
     The present embodiment deals with an electric connecting device whose fitting  323  of the first housing  322  is formed in a cylindrical shape. The four ribs  324  formed on the exterior surface  323   s  of the fitting  323  are disposed at an equal interval in a circumferential direction of the exterior surface  323   s  of the fitting  323 , when viewed from the connecting direction. Similarly, the four supplementary recesses  325  formed on the exterior surface  323   s  are disposed at an equal interval in a circumferential direction of the exterior surface  323   s , when viewed from the connecting direction. Although no illustration is provided, the fitting receiver of the second housing  342  is formed so as to accommodate therein the fitting  323 . Specifically, the interior surface of the fitting receiver has not-illustrated four supplementary recesses for respectively fitting therein the four ribs  324 , and not-illustrated four supplementary ribs to fit in the four supplementary recesses  325 . 
     Further, the electric connecting device of the present embodiment includes a single first terminal  321  and a single second terminal  341 , and is structured as a unipole connector. The electric connecting device and the metal-latch-mountable connector housing may be structured in this way. Note that the reference numeral  361  indicates a rubber boot. 
     The electric connecting device of the present embodiment is adapted so that: the fitting  323  is formed in a cylindrical shape, and the four ribs  324  formed on the exterior surface  323   s  of the fitting  323  is disposed at an equal interval in a circumferential direction of the fitting  323  when viewed from the connecting direction. This simplifies the shape of the housing, and the positions of the ribs. 
     The metal-latch-mountable connector housing  303  of the present embodiment is adapted so that: the fitting  323  is formed in a cylindrical shape, and the four recesses formed on the interior surface of the fitting receiver is disposed at an equal interval in a circumferential direction of the fitting receiver when viewed from the connecting direction. This simplifies the shape of the housing, and the positions of the recesses. 
     Embodiment 3 
     Next, the electric connecting device of Embodiment 3 according to the present invention is described below, mainly focusing on the difference from the above embodiment. Note that the members that are similar to those of the above embodiment are given the same reference symbols and no further explanation is provided hereinbelow. Further, in the present embodiment, members and parts given the reference symbols  403 ,  405 ,  422 ,  422   f ,  422   s ,  422   v ,  422   w ,  422   x ,  423 ,  423   s ,  424 ,  425 ,  426 ,  441 ,  442 ,  442   h ,  442   t ,  446 ,  447 ,  447   d ,  447   t ,  464 , and  465  respectively correspond to the members and parts of the foregoing embodiment given the reference symbols  3 ,  5 ,  21 ,  21   s ,  22 ,  22   f ,  22   s ,  22   v ,  22   w ,  22   x ,  23 ,  23   s ,  24 ,  25 ,  26 ,  41 ,  42 ,  42   h ,  42   t ,  46 ,  47 ,  47   d ,  47   t ,  64 , and  65 . The respective functions of these members and parts are the same as the foregoing embodiment.  FIG. 14  is an exploded perspective view illustrating members constituting an electric connecting device of Embodiment 3 according to the present invention. 
     An electric connecting device of the present embodiment has five first terminals  21  and five second terminals  441 , and is structured as a five pole connector. The electric connecting device may be structured in this way. 
     Embodiment 4 
     Next, the electric connecting device of Embodiment 4 according to the present invention is described below, mainly focusing on the difference from the above embodiment. Note that the members that are similar to those of the above embodiment are given the same reference symbols and no further explanation is provided hereinbelow. Further, in the present embodiment, members and parts given the reference symbols  501 ,  502 ,  503 ,  504 ,  505 ,  522 , and  523  respectively correspond to the members and parts of the foregoing embodiments given the reference symbols  1 ,  2 ,  3 ,  4 ,  5 ,  22 , and  23 . The respective functions of these members and parts are the same as the foregoing embodiment.  FIG. 15  is a plane view illustrating an electric connecting device of Embodiment 4 according to the present invention. 
     An electric connecting device  501  of the present embodiment differs from Embodiment 1 in that, for example, a metal latch  505  is mounted to the first housing  522 , and no metal latch is mounted to the second housing  542 . Unlike the above mentioned embodiment, the present embodiment deals with a case where a metal-latch-mountable connector housing  503  has a main body  522   b  of the first housing  522  and the metal latch  505 . Separation of the first and second housings  522  and  542  from each other is inhibited by latching the metal latch  505  on a not-illustrated latch receiver formed on the interior surface of the second housing  542 . In the foregoing embodiment, the metal latch  5  tries to restore its original state by shrinking during the connecting operation. In the present embodiment however, the metal latch  505  once having been shrunk tries to restore its original state by expanding. This force to expand inhibits separation of the first and second housings  522  and  542  from each other. The electric connecting device may be structured in this way. 
     The metal-latch-mountable connector housing  503  of the present embodiment is for one of a pair of connectors connectable to each other, and includes: a main body  522   b  connectable to a second connector (counterpart connector)  504  of a second housing (counterpart housing)  542 , which supports a connector terminal electrically connectable to a second terminal (counterpart terminal) of the second connector  504 ; and a metal latch  505  which inhibits separation of the main body  522   b  and the second housing  542  from each other. The main body  522   b  is formed as a tube-like fitting  523  to fit in a fitting receiver formed on the second housing  542 , during a connected state in which the pair of connectors are connected to each other. When viewed from a connecting direction in which the pair of connectors connect to each other, the exterior surface of the fitting  523  has (i) plural ribs  24  each projecting in a radial direction of a center portion of the fitting  523 . The plural ribs  24  on the exterior surface of the fitting  523  includes two ribs  24  disposed across from each other over the center portion, along a single line extending through the center line, when viewed from the connecting direction. With this, the connected state of the both connectors is maintained while reducing an effect from vibration, with a simple structure. 
     The metal-latch-mountable connector housing  503  of the present embodiment is adapted so that: the fitting  523  is formed in the shape of a quadrangular tube; and the four ribs  24  are respectively disposed at corner portions of the fitting  523 . This simplifies the shape of the housing and the positions of the ribs or the recesses. 
     Note that the shape of the fitting is not limited to the above, and for example, the fitting may be formed in a cylindrical shape (see Embodiment 2 for the shape of fitting). In such a case, the plural ribs on the exterior surface of the fitting may include two to four ribs which are disposed at an equal interval in a circumferential direction of the fitting, when viewed from the connecting direction. This also simplifies the shape of the housing and the positions of the ribs or the recesses. Note that it is possible to form plural recesses on the exterior surface of the fitting, and form plural ribs on the interior surface of the fitting receiver. 
     It should be noted that the present invention shall not be limited to the embodiments thus described, and various modifications are possible within the scope of the present invention. 
     For example, each of the above embodiments deals with a case where the electric connecting device is used as an equipment-use connector for supplying power. However, the electric connecting device may be used as an equipment-use connector for transmitting/receiving electric signals. The use of the electric connecting device is not limited to equipment, and the electric connecting device may be used for a relay or a substrate. 
     Further, the electric connecting device is not limited to one such that the second connector is connected to the first connector which is fixed, and the electric connecting device may be such that the first connector is connected to the second connector which is fixed. 
     Further, the shape of the fitting may be formed in a shape other than the shapes mentioned above. For example, the fitting may be formed in such a tube-like shape whose cross section is a polygon such as triangle or pentagon. 
     Further, the metal latch is not particularly limited, provided that the metal latch is mountable to a housing of one of a pair of connectors connectable to each other. 
     Further, Embodiment 1 deals with a case where the cover  47  and the metal latch  5  contact each other during the covering state. However, the cover  47  does not have to contact the metal latch  5  during the covering state. When the cover  47  and the metal latch  5  contact each other as in the present embodiment, the metal latch  5  and the second housing  42  needs to have therebetween a certain play (which enables restoration of the metal latch  5  from its resilient deformation is not inhibited) so that a clicking feel is given at the time of locking operation. 
     Further, the metal latch is preferably formed so that only the latch main portion (see latch main portion  52  surrounded by the frame of  FIG. 10(   b )) has a C-shape or U-shape. The shape of the tip portions of the metal latch is not particularly limited. That is, the entire metal latch may have a shape which may not be referred to as a C-shape or U-shape, as illustrated in  FIGS. 16(   a ) and  16 ( b ). Note that portions given the reference numerals  605 ,  652 , and  655  in  FIGS. 16(   a ) and  16 ( b ) respectively correspond to the portions of the foregoing embodiment given the reference numerals  5 ,  52 , and  55 . Likewise, portions given the reference numerals  705 ,  752 , and  755  respectively correspond to portions of the foregoing embodiment given the reference numerals  5 ,  52 , and  55 . 
     Further, the connection sloping surfaces  22   s  and the unlocking sloping surfaces  42   p  may be omitted. Further, the guide projections  22   w , guide projection  22   v , guide grooves  42   x , and guide groove  42   v  may be omitted. Further, the side recess  27 , fitting recess  22   m , and fitting projection  42   m  may be omitted. Further, the shape of the terminals in the present embodiment are solely to serve as examples, and the shape of the terminals are not limited to those of the above embodiment. For example, the terminals are structured so that the second terminal is inserted into the first terminal, as opposed to the present embodiment. Further, the cover  47  and the groove  42   d  may be omitted. 
     Further, the above embodiments deal with a case where the metal latch is formed by curving a single rod-like member. The metal latch  5  however is not limited to this, and for example, it is possible to form the metal latch  5  by bending a plate member. 
     Further, the material of the latch is not limited, and plastic or the like may be adopted as the material of the latch. 
     While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.