Patent Publication Number: US-6902420-B2

Title: Connector lock structure

Description:
BACKGROUND OF THE INVENTION 
   This invention generally relates to a connector lock structure, and more particularly to a connector lock structure having a mechanism for releasing a locked condition of connector housings. 
   Hitherto, there has been a lock structure shown in  FIGS. 5 and 6  (see, for example, JP-A-2000-150069), which serves as a structure for connecting male and female connector housings to each other, for locking this connected condition, and for releasing this locked condition. 
   The lock structure shown in  FIGS. 5 and 6  is configured so that a lock portion  1  having a lock arm  3  and a releasing arm  5  is formed integrally with the female connector housing. 
   As shown in  FIG. 6 , the lock arm  3  includes two curved leg portions  3   a  formed in such a way as to upwardly protrude and extend from an outer wall  7 , two arm portions  3   b  respectively and horizontally extending from the two leg portions  3   a  along a connector fitting direction toward a latch portion of a counterpart connector, and an engaging portion  3   c  which is formed in such a manner as to connect ends of the two arm portions  3   b  to each other and has a locking claw  3   d.    
   As shown in  FIG. 6 , the releasing arm  5  includes two leg portions  5   a  and two arm portions  5   b . The two leg portions  5   a  upwardly protrudes and extends from the outer wall  7  and are thinner than the leg portions  3   a . The two arm portions  5   b  is respectively formed on the two leg portions  5   a . Each of the two leg portions  5   a  is formed at an outer side of an associated one of the leg portions  3   a  and at nearly the same position as that of the associated leg portion  3   a.    
   The arm portions  5   b  are formed so that end parts thereof extend in a direction opposite to the engaging portion  3   c  and are connected to each other to thereby form the releasing portion  5   c , and that the other end parts thereof extend toward and are connected to the engaging portion  3   c.    
   In a case of releasing the locked condition of the lock portion  1 , the releasing portion  5   c  is depressed in the direction of an arrow A as shown in FIG.  6 . The releasing arm  5  turns in response to a force exerted on the releasing portion  5   c  so as to surely upwardly and pivotally move the engaging portion  3   c  in the direction of an arrow B around each of the leg portions  5   a . As a result, the locking claw  3   d  is disengaged from the latch portion of the counterpart connecter (not shown) to release the locked condition. 
   Because the releasing arm  5  has the leg portions  5   a , the engaging portion  3   c  surely displaces in a lock releasing direction B in response to a force applied to the releasing portion  5   c  regardless of a direction and an angle of application of the force. Consequently, cancellability of the structure is enhanced. 
   However, in the case of the lock structure of the related lock portion  1 , when the engaging portion  3   c  is engaged with and disengaged from the latch portion of the counterpart connector, the lock arm  3  and the releasing arm  5  swing around the leg portions  3   a  and  5   a  protruding upwardly from the outer wall  7  of the connector housing, respectively. 
   Thus, bending stresses are apt to be concentrated at bent portions k 1  at each of which an associated one of the leg portions  3   a  intersects with an associated one of the arm portions  3   b , bent portions k 2  at each of which an associated one of the leg portions  5   a  intersects with an associated one of the arm portions  5   b , and corner portions k 3  and k 4  at which the leg portions  3   a  and  5   a  continued to the outer wall  7  of the connector housing, respectively. Fatigue due to stress concentration in the leg portions  3   a  and  5   a  may result in permanent deflections thereof and may cause reduction in an engaging strength of the engaging portion  3   c , or fatigue destruction thereof. 
   In the lock structure of the related lock portion  1 , a position, at which the engaging portion  3   c  of the lock arm  3  is equipped, is away from the outer wall  7  of the connector housing by a height h of each of the leg portions  3   a . Thus, the lock structure of the related lock portion  1  has a problem in that the size of the connector housing increase owing to increase in the dimension of the outside diameter of the connector housing, which is caused by outward protrusion of the engaging portion  3   c.    
   SUMMARY OF THE INVENTION 
   It is therefore an object of the present invention to provide a connector lock structure enabled to maintain a stable engaging strength over a long time and also enabled to prevent increase in the outside dimension thereof in size. 
   In order to achieve the above object, according to the present invention, there is provided a connector lock structure, comprising: 
   a first connector housing; 
   a second connector housing, which is fitted to the first connector housing; 
   a flexible lock member, which is frontwardly extended from the first connector housing along a connector fitting direction, and which has an engagement portion provided at an end portion thereof; 
   a latch member, which is provided on the second connector housing, and which is engaged with the engagement portion; 
   an operating arm, which upwardly protrudes from the end portion of the lock member and rearwardly extends, and which has a operation portion provided at a rear end portion thereof; and 
   a fulcrum projection, which is provided on at least one of an outer wall face of the lock member and a bottom surface of the operating arm facing the outer wall face. 
   Preferably, the flexible lock member is formed by a part of an outer wall of the first connector housing. The fulcrum projection is provided on at least one of an outer wall face of the first connector housing and the bottom surface of the operating arm facing the outer wall face of the first connector housing. 
   Preferably, when the operating portion is depressed, the operating arm pivotally swing around the fulcrum projection as a fulcrum so as to deform the end portion of the lock member upwardly so that an engagement between the latch member and the engagement portion is released. 
   Preferably, a presser portion is provided on at least one of the lock member and the operating arm. A preventing member is provided on an outer face of the first connector housing, and engages with the presser portion so as to prevent the lock member from lifting. 
   In the above configurations, in a case where the locked condition of the engaging portion provided at an end portion of the flexible lock member and the latch member of the second connector housing is canceled, when the operation portion provided at the rear end portion of the operating arm is depressed, the operating arm pivotally swing around the fulcrum projection placed on the bottom thereof, so that the end of the operating arm upwardly moves. 
   Then, when the end of the operating arm upwardly moves, an upward force acts upon an end portion of the flexible lock member to which the end portions of the operating arm are connected. Thus, the end portion of the flexible lock member is upwardly bending-deformed. Consequently, the engaging portion provided at the end portion of the flexible lock member disengages from the latch member of the second connector housing. 
   That is, when the engagement between the engaging portion and the latch member of the second connector housing is canceled, the operating arm pivotally swing around the fulcrum projection. Moreover, when the engaging portion engages with and disengages from the latch member of the second connector housing, the entire flexible lock piece is bending-deformed like a cantilever, an end of which is a free end. Thus, there are no leg portions similar to those, at which stress concentration is apt to occur, in the related lock structure. 
   Thus, the lock member according to the invention can prevent occurrences of permanent deflection resulted from fatigue due to stress concentration. Consequently, the lock structure can obtain excellent durability that enables the connector to maintain a stable engaging strength over a long time. 
   Further, the flexible lock member is frontwardly extended from the front end of the step-like part of the upper wall of the first connector housing along the connector fitting direction. Thus, the lock structure does not need leg portions that upwardly protrude from the outer wall surface of the first connector housing. Consequently, the connector can be designed so that the position, at which the engaging portion of the flexible lock member is provided, can be adjusted to the position of the upper wall of the first connector housing. 
   Thus, the lock structure can suppress the flexible lock member and the operating arm from protruding upwardly from the outer wall surface of the first connector housing. Consequently, the lock structure according to the invention can prevent the outside dimension of the first connector housing from increasing owing to the protrusion of the flexible lock member and the operating arm. Thus, the miniaturization of the connector can be achieved. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein: 
       FIG. 1  is a perspective view illustrating a connector employing a connector lock structure according to an embodiment of the invention; 
       FIG. 2  is a longitudinally sectional view illustrating the connector shown in  FIG. 1 ; 
       FIG. 3  is a longitudinally sectional explanatory view illustrating releasing of the locked condition of the connector shown in  FIG. 2 ; 
       FIG. 4  is a front view illustrating a lock portion shown in  FIG. 1 ; 
       FIG. 5  is a perspective view illustrating a related connector lock structure; and 
       FIG. 6  is a longitudinally sectional view illustrating the connector lock structure shown in FIG.  5 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Hereinafter, a connector lock structure according to an embodiment of the invention is described in detail with reference to the accompanying drawings. 
     FIG. 1  is a perspective view illustrating a connector employing a connector lock structure according to an embodiment of the invention.  FIG. 2  is a longitudinally sectional view illustrating the connector shown in FIG.  1 .  FIG. 3  is a longitudinally sectional explanatory view illustrating releasing of the locked condition of the connector shown in FIG.  2 .  FIG. 4  is a front view illustrating a lock portion shown in FIG.  1 . 
   As shown in  FIGS. 1 and 2 , a connector  21  according to this embodiment includes a female connector housing  24 , which accommodates and holds a plurality of male terminal metal fittings  23 , and also includes a male connector housing  27 , which accommodates and holds a plurality of female terminal metal fittings  29 . 
   When the female connector housing  24  and the male connector housing  27  are fitting-connected to each other, the connector lock structure according to this embodiment locks these connector housings each other by engaging a lock portion  30  provided on an outer (or upper) wall of the male connector housing  27  with an engaging portion  28  provided on an outer (or lower) wall of the female connector housing (or counterpart connector housing)  24 . 
   As shown in  FIGS. 1 and 2 , the lock portion  30  has a flexible lock piece  33 , three operating arms  34  and a pair of fulcrum projections  36 . The flexible lock piece  33  is frontwardly extended from a front end of a step-like part of the upper wall  31  of the male connector housing  27  along a connector fitting direction (the rightward direction, as viewed in  FIG. 2 ) and has an engaging portion  33   a  that is engaged with a latch portion  28  of the female connector housing  24  and provided at an end portion thereof. The three operating arms  34  upwardly protrudes from the end portion of the flexible lock piece  33  and rearwardly extends and has a pushing operation portion  34   a  provided at a rear end portion thereof. Each of the pair of fulcrum projections  36  is provided in such a way as to project toward an outer wall surface  31   a  of the male connector housing  27  from the bottom surface of a middle part of each of the operating arms  34  facing the outer wall surface  31   a.    
   Moreover, as shown in  FIGS. 1 and 4 , in the case of this embodiment, a flat-plate-like presser piece  41  on a place close to a rear end of each of both the outer side faces of a set of the operating arms  43  in such a way as to horizontally project therefrom. Rise preventing members  43  to be engaged with the presser pieces  41  are provided on both the outer wall surface  31   a  of the male connector housing  27  so as to prevent a rising of the operating arms  34 . 
   As shown in  FIG. 4 , each of the rise preventing members  43  includes a support wall  43   a , which upwardly protrudes from the outer wall surface  31   a  of the upper wall  31 , and a presser portion  43   b  protruding upwardly from the top of this support wall  43   a  and extending nearly horizontally above an associated one of the presser pieces  41 . The rise preventing member  43  regulates the rising of the operating arms  34  thereby to prevent the flexible lock piece  33  from upwardly being bending-deformed. 
   Next, an operation of the lock structure of such a configuration is described hereinbelow. 
   When the female connector housing  24  and the male connector housing  27  are connected to each other, the engaging portion  33   a  provided at an end portion of the flexible lock piece  33  is upwardly pushed by the latch portion  28  of the female connector housing  24 . 
   Consequently, the flexible lock piece  33  is upwardly bending-deformed, so that the engaging portion  33   a  climbs over and engages with the latch portion  28 . Thus, the connected condition of the connector housings of the connector  21  is locked. 
   In a case where the connector housings of the connector  21  are disconnected from each other by releasing the locked condition of the engaging portion  33   a  of the flexible lock piece  33  and the latch portion  28  of the female connector housing  24 , the pushing operation portion  34   a  provided at the rear end portion of each of the operating arms  34  is depressed in the direction of an arrow C. 
   Then, the fulcrum projections  36  disposed on the bottom of a set of the operating arms  34  abut against the outer wall surface  31   a  of the upper wall  31 . The operating arms  34  pivotally swing around the fulcrum projections  36 , so that the end of each of the operating arms  34  upwardly moves (in the direction of the arrow C). 
   When the end of each of the operating arms  34  upwardly moves, an upward force acts upon an end portion of the flexible lock piece  33  to which the end portions of the operating arms  34  are connected. Thus, the end portions of the flexible lock piece  33  are upwardly bending-deformed. Consequently, the engaging portion  33   a  provided at the end portion of the flexible lock piece  33  disengages from the latch portion  28  of the female connector housing  24 . 
   When the engaging portion  33   a  is released from the latch portion  28  of the female connector housing  24 , the operating arms  34  pivotally swing around the fulcrum projections  36 . Moreover, when the engaging portion  33   a  engages with and disengages from the latch portion  28  of the female connector housing  24 , the entire flexible lock piece  33  is bending-deformed like a cantilever, an end of which is a free end. Thus, there are no leg portions like those  3   a  and  5   a , at which stress concentration is apt to occur, in the related lock structure. 
   The lock portion  30  can prevent occurrences of permanent deflection resulted from fatigue due to stress concentration. Consequently, the lock structure can obtain excellent durability that enables the connector to maintain a stable engaging strength over a long time. 
   Moreover, the flexible lock piece  33  is frontwardly extended from the front end of the step-like part of the upper wall  31  of the male connector housing  27  along the connector fitting direction. Thus, the lock structure does not require leg portions that upwardly protrude from the outer wall surface  31   a  of the connector housing  27 . Consequently, the connector can be designed so that the position, at which the engaging portion  33   a  of the flexible lock piece  33  is provided, can be adjusted to the position of the upper wall  31  of the male connector housing  27 . 
   The lock structure can suppress the flexible lock piece  33  and the operating arms  34  from protruding upwardly from the outer wall surface  31   a  of the male connector housing  27 . Consequently, the lock structure according to the invention can prevent the outside dimension of the male connector housing  27  from increasing owing to the protrusion of the flexible lock piece  33  and the operating arms  34 . Thus, the miniaturization of the connector  21  can be achieved. 
   Further, the rise preventing members  43  engaged with the presser pieces  41  of a set of the operating arms  34  for preventing the rise of the operating arms  34  are provided on the outer wall surface  31   a  of the male connector housing  27  in the lock portion  30  of this embodiment. 
   Thus, even when, for example, a bite-in of foreign matters to the lock portion  30  occurs and an external force is applied thereto in a direction in which an end portion of the flexible lock piece  33  is lifted, during a state in which the female connector housing  24  and the male connector housing  27  are locked, the rise preventing members  43  engage with the presser pieces  41  of a set of the operating arms  34 , so that the flexible lock piece  33  can be prevented from being upwardly bending-deformed. 
   That is, the flexible lock piece  33  is prevented from being improperly upwardly (that is, in a direction in which the locked condition is canceled) bending-deformed. Thus, an undesirable releasing of the locked condition of the connector housings can be prevented. Connectors can be prevented from being broken due to excessive deformation thereof. Consequently, the lock portion  30  can enhance reliability of the lock. 
   Incidentally, the configurations of the connector housing, the counterpart connector housing, the flexible lock piece, the operating arms and the fulcrum projections according to the connector lock structure of the invention are not limited to those of the embodiment. Needless to say, such constituent elements may have various configurations without departing from the spirit of the invention. 
   For example, although the fulcrum projections  36  are provided on the bottom surface of the operating arms  34  in the embodiment, the fulcrum projections may be provided on the outer wall surface  31   a  of the male connector housing  27 , which faces the bottom surface of the set of the operating arms  43 , in such a way as to project therefrom. It is sufficient that the fulcrum projections  36  are provided on at least one of the outer wall surface  31   a  of the male connector housing  27  and the bottom surface of the operating arms  43 , which face each other.