Abstract:
A connector assembly making an electrical connection through the mutual engagement of a pair of connectors. One of the connectors has a flexible lock arm, and the other connector has a lock receiver that links to this lock arm. The connector that has the lock arm also has an arm protection part that extends over a substantial portion of an outer surface of the lock arm.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   The present application claims priority from Japanese Patent Application No. 2007-203656, which was filed on Aug. 3, 2007 and is hereby incorporated by reference in its entirety herein. 
   FIELD OF THE INVENTION 
   The present invention relates to an engagement lock structure for a connector that provides an electrical connection through the mutual engagement of a pair of connectors. 
   BACKGROUND OF THE INVENTION 
   For example, as is shown in  FIG. 4(   a ), one connector  110  belonging to a pair of conventional electrical connectors that are mutually engaged is equipped with a flexible lock arm  113 , while the other connector  120  is equipped with a lock receiver  122 . As shown in  FIG. 4(   b ), the lock arm  113  is elastically linked to the lock receiver, such that the connectors are locked in an engaged position. 
   However, the lock arm  113  prior to the connector engagement is such that it protrudes from the outer periphery of the connector housing  111 , and therefore the lock arm  113  can be struck during application operations, easily resulting in plastic deformation or breakage and thus causing insufficient linking strength of the lock arm  113  or even a condition in which linking is not possible. In this case, the connector must be replaced with a new one, but in the current state in which replacement is difficult to carry out, this can result in a significant drop in operational efficiency. 
   In Published Unexamined Japanese Patent Application No. JP2004-179133, a technology is disclosed in which breakage due to bending is prevented through the use of a ring-shaped lever receiver. However, not only is the lock lever made longer than the length required for the lock, there is the relationship regarding the undercut between the lock lever part and lever receiver part in the formation of a single unit using resin material, and the problem of high cost results from a complex forming process. 
   SUMMARY OF THE INVENTION 
   In light of the technological problems noted above, it is an object of the present invention to provide a connector that has an excellent level of protection from breakage of the lock arm because of external force and can be produced at low cost. 
   The connector according to the present invention is one in which an electrical connection is made through the mutual engagement of a pair of connectors, and one of the connectors has a flexible lock arm while the other connector has a lock receiver that links to this lock arm, such that the connector that has the lock arm has an arm protection part that extends to the outside of the lock arm. 
   Here, the reason for equipping the connector having a flexible lock arm with an arm protection part is that the bending of the lock arm can easily lead to deformation or breakage because of external force when linked to the lock receiver. 
   Further, the lock arm may be installed on either the socket connector side or the plug connector side. 
   The lock arm may be easily produced through injection molding of resin by forming a base part on the outer periphery of the connector housing of one of the connectors mentioned above. This base part has a lock arm that extends in an engagement direction with the other connector, a specified space on the outer side of this lock arm, and an arm protection part that extends for a specified length along this lock arm. 
   Here, the reason for having an arm protection part that extends for a specified length is not because of any need for conforming to the length of the lock arm. Any length is suitable that avoids any hindrance with the lock receiver, and that allows the arm protection part to be linked with the lock receiver. 
   With the connector according to the present invention, an arm protection part that protects the lock arm is provided on the outer side of the lock arm, and for this reason, the lock arm is effectively protected by the arm protection part during application operations, thus preventing breakage of the lock arm. 
   The arm protection part and lock arm extend from the base of the connector housing in the engagement direction with a connector, and thus it is easy to make a single-unit formation with the connector housing through injection molding. Therefore, a connector having an arm protection part can be produced at low cost. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will become more readily apparent from the Detailed Description of the Invention, which proceeds with reference to the drawings, in which: 
       FIG. 1  is an external view of an embodiment of the connector related to the present invention. 
       FIG. 2(   a ) is an external view of the socket connector equipped with a lock arm as well as a plug connector equipped with a lock receiver prior to the engagement of the two connectors; 
       FIG. 2(   b ) is an explanatory drawing in which the housings corresponding to (a) are drawn as longitudinal sections; 
       FIG. 3(   a ) is an external view of the socket connector and plug connector in their engaged state; 
       FIG. 3(   b ) is an explanatory drawing in which the housings corresponding to (a) are drawn as longitudinal sections; and 
       FIGS. 4(   a ) and  4 ( b ) show the engagement lock structure of a conventional connector. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The following listing provides a key to the reference numerals and elements depicted in the drawings: 
   
     
       
             
             
             
           
         
             
                 
                 
             
           
           
             
                 
               1a, 1b: 
               Electric lines 
             
             
                 
               2a, 2b: 
               Core wires 
             
             
                 
               3a, 3b: 
               Cover parts 
             
             
                 
               10: 
               Socket connector 
             
             
                 
               11: 
               Socket connector housing 
             
             
                 
               12: 
               Base part 
             
             
                 
               13: 
               Lock arm 
             
             
                 
               13a: 
               Flexible arm part 
             
             
                 
               13b: 
               Linking catch 
             
             
                 
               13c: 
               Arm bending space part 
             
             
                 
               14: 
               Arm protection part 
             
             
                 
               14a: 
               Insertion space 
             
             
                 
               15: 
               Terminal storage chamber 
             
             
                 
               15a: 
               Lance clip part 
             
             
                 
               16: 
               Cylindrical engagement part 
             
             
                 
               16a: 
               O-ring 
             
             
                 
               17: 
               Cylindrical insertion part 
             
             
                 
               18: 
               Contracting tube 
             
             
                 
               19: 
               Socket terminal 
             
             
                 
               19a 
               Lance 
             
             
                 
               20: 
               Plug connector 
             
             
                 
               21: 
               Plug connector housing 
             
             
                 
               22: 
               Lock receiver 
             
             
                 
               23: 
               Linking part 
             
             
                 
               23a: 
               Linking end 
             
             
                 
               24: 
               Arm insertion hole 
             
             
                 
               25: 
               Terminal storage chamber 
             
             
                 
               25a: 
               Lance clip part 
             
             
                 
               26: 
               Cylindrical engagement part 
             
             
                 
               27: 
               Cylindrical insertion part 
             
             
                 
               28: 
               Contracting tube 
             
             
                 
               29: 
               Plug terminal 
             
             
                 
               29a: 
               Lance 
             
             
                 
                 
             
           
        
       
     
   
     FIG. 1  shows an embodiment of a connector construction according to the present invention as applied to a socket connector. 
   Further,  FIG. 2(   a ) is a external view of a socket connector  10  and plug connector  20  prior to engagement, while  FIG. 2(   b ) is an explanatory drawing in which the respective housings corresponding to  FIG. 2(   a ) are drawn as longitudinal sections. 
   As shown in  FIG. 1 , a pair of base parts  12  are erected in symmetrical positions such that they hold the housing  11  between them on the outer periphery of the housing  11  of the socket connector  10 . 
   Also, a flexible lock arm  13  and arm protection part  14  that are linked to a lock receiver  22  of a plug connector  20  of the mating side are installed such that they extend from the respective base parts  12  in the engagement direction with the connector. 
   Between the lock arm  13  and socket connector housing  11 , an arm bending space part  13   c  is provided in order to allow bending of the lock arm  13 . 
   The lock arm  13  is equipped with a flexible arm part  13   a  that extends from the base part  12  in the engagement direction with the connector, as well as a linking catch  13   b  that protrudes outward toward the tip of the flexible arm part  13   a.    
   The linking catch  13   b  moves in the inner and outer directions by the bending of the flexible arm part  13   a  in the inner and outer directions with respect to the socket connector housing  11 . 
   The arm protection part  14  is equipped with an insertion space  14   a  between it and the lock arm  13 , and this is formed such that it extends from the base part  12  with respect to the socket connector housing  11  along the outer side beyond the lock arm  13  and is nearly parallel to the lock arm  13 . 
   Due to the low level of elasticity of the part of the lock arm  13  that extends from the base part  12 , specifically the flexible arm part  13   a , plastic deformation can occur easily if it is struck, and if the lock arm  13  receives external force in the bending direction to the extent that plastic deformation occurs, the linking strength can drop significantly. 
   The arm protection part  14  extends from the base part  12  along the outer side in the bending direction of the lock arm  13 , and from the external force of the bending direction of the lock arm  13 , breakage of the lock arm  13  is prevented, particularly with the protection in the vicinity of this extended flexible arm part  13   a.    
   The respective arm protection parts  14  and lock arms  13 , with a right-angle directional perspective in the bending direction of the lock arm as well as the engagement direction of the connector with respect to  FIG. 1 , are formed in such a way that they are turned back in an abbreviated U-shape by the extended base part  12 . 
   Accordingly, the arm protection part  14 , lock arm  13 , and base part  12  can be resin-formed in a single unit on the socket connector housing  11  through the use of a forming die which narrows in the engagement direction of the connector as well as the right angle in the bending direction of the lock arm. 
   As shown in  FIGS. 2(   a ) and  2 ( b ), the socket connector housing ii is cylindrical in shape and provided with a terminal storage chamber  15  that passes through in the engagement direction. Stored within the terminal storage chamber  15  is a socket terminal  19  in which a core wire  2   a  of an electric line  1   a  is connected to one end. 
   A cylindrical engagement part  16  is provided at the front position of the engagement direction of the socket connector housing  11 , and a cylindrical insertion part  17  is provided at the rear position. 
   The outer periphery of the cylindrical engagement part  16  is equipped with an O-ring  16   a  for shutting out water. 
   The socket terminal  19  is inserted into the terminal storage chamber  15  from the cylindrical insertion part  17 , and the lance  19   a  of the socket terminal  19  is snapped into place in the lance clip part  15   a  on the inner wall of the terminal storage chamber  15  in order to install the socket terminal  19  within the terminal storage chamber  15 . 
   Between the socket connector housing  11  and the electric line  1   a , from the cylindrical insertion part  17  to the cover  3   a  for the electric line  1   a , a shrink tube  18  is used to provide a cover and prevent water contact. 
   A housing  21  for a plug connector  20  is a cylindrical shape equipped with a terminal storage chamber  25  that passes through in the engagement direction, and stored within the terminal storage chamber  25  is a plug terminal  29  in which a core wire  2   b  of an electric line  1   b  is connected to one end. 
   A cylindrical engagement part  26  is provided at the front position of the engagement direction of the plug connector housing  21 , and a cylindrical insertion part  27  is provided at the rear position. 
   The plug terminal  29  is inserted into the terminal storage chamber  25  from the cylindrical insertion part  27 , and a lance  29   a  of the plug terminal  29  is snapped into place in the lance clip part  25   a  on the inner wall of the terminal storage chamber  25  in order to install the plug terminal  19  within the terminal storage chamber  25 . 
   Between the plug connector housing  21  and the electric line  1   b , from the cylindrical insertion part  27  to the cover  3   b  for the electric line  1   b , a shrink tube  28  is used to provide a cover and prevent water contact. 
   A lock receiver  22  is provided in the position corresponding to the lock arm  13  of the socket connector  10  on the outer periphery of the plug connector housing  21 . 
   The lock receiver  22 , which passes through in the connector engagement direction, is somewhat cylindrical in shape, and an arm insertion hole  24  is installed on the inside of this cylinder in order to plug in the flexible arm part  13   a  of the lock arm  13  during engagement of the connector. 
   A linking part  23  in which the linking catch  13   b  is elastically linked when the connector is engaged, as the linking catch  13   b  of the socket connector  10  slides and plugs into the plug-in space  14   a , is provided on the cylindrical outer side wall. 
     FIG. 3(   a ) shows an external view of the socket connector  10  and plug connector  20  in their engaged state, and  FIG. 3(   b ) is an explanatory diagram of the housings corresponding to  FIG. 3(   a ) drawn as longitudinal sections. 
   With regard to the socket connector  10  and plug connector  20 , the cylindrical engagement part  16  of the socket connector housing  11  is inserted into the cylindrical engagement part of the plug connector housing  21  so that the socket terminal  19  and plug terminal  29  are mutually engaged. 
   Accordingly, the electric line  1   a  connected to the socket terminal  19  forms a trunk connection with the electric line  1   b  connected to the plug terminal  29 . 
   As for the engaged part between the socket connector  10  and plug connector  20 , an O-ring  16   a  provided on the outer periphery of the cylindrical engagement part  16  of the socket connector  10  slides into the inner surface of the cylindrical engagement part  26  of the plug connector  20  to cut off water, and thus water contact with the connection between the socket terminal  19  and plug terminal  29  is prevented. 
   The linking catch  13   b  slides into the linking part  23  during connector engagement, and while the flexible arm part  13   a  bends inward, the lock arm  13  is inserted into the arm insertion hole  24  of the lock receiver  22 , and at the connector engagement position the linking catch  13   b  makes an elastic link in the linking end  23   a  at the rear end of the linking part  23  to lock the connector engagement in place. 
   It is within the scope of the present invention to include all foreseeable equivalents to the elements of the present invention as disclosed with reference to  FIGS. 1-3 . The examples provided by the disclosure are not to be interpreted as limiting the invention beyond that which is claimed.