Abstract:
According to the invention, in a card connector, although only a simple countermeasure that the shape of a bottom face of an escape path in a cam body is slightly changed is taken, accidental ejection of a card due to a drop impact or the like is caused to hardly occur, without impairing the card insertion operability.  
     In the card connector of the invention, a slider  70  is longitudinally movably attached to a case  50.  The card connector has a cam mechanism  10  having functions of locking the slider  70  to a pushed position, and canceling the locked state at the pushed position. The cam mechanism  10  has an engagement pin  40  and a cam body  20.  A loop groove  21  of the cam body  20  has an engagement portion  24,  an escape path  26,  and a stepped surface  31.  An engagement end  41  of the engagement pin  40  is elastically pressed against a bottom face of the escape path  26.  The bottom face of the escape path  26  has an inclined surface  32  of a rising gradient which is directed toward an upper edge of the stepped surface  31.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a card connector, and more particularly to a so-called push-push type card connector in which positioning of a card to a card set position, and ejection of the card from the card set position are alternately conducted by repeating an operation of pushing the card.  
           [0003]    2. Description of the Prior Art  
           [0004]    Conventionally, card connectors configured in the following manner are known. When an initial pushing operation is conducted on a card inserted into a card insertion space of a case, a slider is pushed from a standby position to a pushed position, and the slider which reaches the pushed position is locked to the position so that the card is positioned to a card set position. By contrast, when a second pushing operation is conducted on the card, the locked state of the slider is canceled, and the card is retracted together with the slider to be ejected. In some of such card connectors, the functions of locking the slider and canceling the locked state are realized by a cam mechanism. The cam mechanism is configured as shown in FIGS. 12 and 13.  
           [0005]    [0005]FIG. 12 is a schematic perspective view showing a cam body  20  of a cam mechanism  10  which is employed in a conventional card connector, and FIG. 13 is a longitudinal side section view showing main portions of the cam mechanism  10 .  
           [0006]    The cam mechanism  10  comprises the cam body  20 , and an engagement pin  40  which is formed by bending an elastic wire member. A loop groove  21  is formed in the cam body  20 . The loop groove  21  comprises: a forward path  22 ; a return path  23 ; a protruding engagement portion  24  which is formed between the paths; a lead-in path  25  which elongates from a forward-path end portion  22   a  to the engagement portion  24 ; and an escape path  26  which elongates from the engagement portion  24  to a return-path start portion  23   a.  The loop groove  21  is formed into a slender heart shape as a whole, and the lead-in path  25  and the escape path  26  form a heart-shape recess.  
           [0007]    In the cam mechanism  10 , the cam body  20  is resiliently urged in the direction of the arrow A of FIG. 12 by an urging force indicated by the arrow A. By contrast, a basal portion (not shown) of the engagement pin  40  is swingably supported at a constant position, and an engagement end  41  at the tip end of the pin is always fitted into the loop groove  21 . At the initial position, the engagement end  41  is positioned in a junction  27  of the start portion of the forward path  22  and the end portion of the return path  23  (this state is not shown in the figures). The engagement pin  40  is always elastically pressed against a bottom face of the loop groove  21  by the elasticity of the pin itself or by a spring piece which is not shown.  
           [0008]    When, in a state where the engagement end  41  of the engagement pin  40  is positioned in the junction  27  of the loop groove  21 , the cam body  20  is pushed against the urging force A, the engagement end  41  moves along the forward path  22  of the loop groove  21  to reach the forward-path end portion  22   a.  When the pushing force is canceled at this timing, the cam body  20  is pushed back by the urging force A, so that the engagement end  41  moves along the lead-in path  25  and is then engaged with the engagement portion  24  as shown in FIG. 12. When the cam body  20  is then pushed against the urging force A, the engagement end  41  moves along the escape path  26  to reach the return-path start portion  23   a.  When the pushing force is canceled at this timing, the cam body  20  is pushed back by the urging force A, so that the engagement end  41  moves along the return path  23  and then returns to the junction  27 .  
           [0009]    In the conventional card connector, the cam body  20  is disposed integrally with a slider (not shown) which is longitudinally movably attached to a case (not shown) forming a card insertion space, and the urging force A is applied to the slider. The slider is configured so that it is pushed by a card which is inserted into the card insertion space, to be moved from a standby position to a pushed position corresponding to the card set position. Then, the engagement end  41  is engaged with the engagement portion  24  as shown in FIG. 13, whereby the slider is locked to the pushed position. Therefore, the card is positioned to the card set position by the first card pushing operation, and terminals of the card are in contact with contacts disposed in the case so as to make electrical connections therebetween. By contrast, when, in the state where the slider is locked, the slider is pushed by the card, the engagement end  41  moves along the escape path  26  to be disengaged from the engagement portion  24  as described above, so that the locked state of the slider is canceled. Then, the engagement end  41  returns via the return path  23  to the junction  27 , whereby the card is ejected. Therefore, the locked state of the slider is canceled by the second card pushing operation, and the card which has been positioned to the card set position is ejected.  
           [0010]    As seen from FIGS. 12 and 13, the cam mechanism  10  which is employed in the conventional card connector comprises a stepped surface  31  in the boundary between the escape path  26  of the loop groove  21  of the cam body  20  and the return path  23 . After the engagement end  41  moves along the escape path  26  and reaches the return-path start portion  23   a,  during retraction of the cam body  20 , the stepped surface  31  slides in contact with the engagement end  41 , whereby the engagement end  41  is retained in the return path  23 , so that the engagement end  41  is prevented from reversely moving to a position a where the engagement end is to be engaged with the engagement portion  24 . A bottom face  26   a  of the escape path  26  is formed as a horizontal surface. In the second card pushing operation, therefore, the engagement end  41  which is elastically pressed against the horizontal bottom face  26   a  of the escape path  26  by the function of the spring piece slides on the bottom face  26   a  and passes over the stepped surface  31  to reach the return-path start portion  23   a.    
           [0011]    A prior art example discloses a structure in which a cam mechanism which is similar to the cam mechanism  10  is employed so that a slider is locked or the locked state is canceled (for example, see Japanese Patent No. 3,083,778).  
           [0012]    Another prior art example discloses a structure in which a cam mechanism which is similar to the cam mechanism  10  is employed so that a slider is locked or the locked state is canceled. The other prior art example discloses also a structure in which means for directly engaging an elastic lock piece of the slider with a notch of a card is employed as means for positioning the card to a card set position, and an engagement end of an engagement pin of the cam mechanism is elastically pressed against a bottom face of a loop groove on the side of a cam body by a spring piece formed by stamping and raising a metal cover constituting a case (for example, see Japanese Patent Application Laying-Open No. 2002-134224).  
         SUMMARY OF THE INVENTION  
         [0013]    In the cam mechanism  10  shown in FIGS. 12 and 13, in the state where the slider is locked to the pushed position, i.e., the state where the engagement end  41  of the engagement pin  40  is engaged with the engagement portion  24  of the cam body  20 , the engagement portion  24  is pushed against and engaged with the engagement end  41  by the urging force A, and hence there does not occur a situation where the slider is retracted and the card is ejected. When any force such as a reaction due to a drop impact which is larger than the urging force A is applied to the slider in the direction opposite to the urging force A, however, a situation where the engagement end  41  moves along the escape path  26  to escape into the return-path start portion  23   a  in the same manner as the case of the second card pushing operation may possibly occur. As a result, there occurs a situation where the locked state of the slider is canceled and the card is accidentally ejected. Particularly, the cam mechanism has the structure in which the bottom face  26   a  of the escape path  26  is a horizontal surface, and the level relationships are set with setting the stepped surface  31  as a boarder so that the bottom face  26   a  of the escape path  26  is higher and the bottom face of the return path  23  is lower. As a result, circumstances in which such a situation is allowed to easily occur are produced. When a situation where the locked state of the slider is canceled and the card is accidentally ejected occurs, electrical connections between the terminals of the card and the contacts of the case are interrupted, thereby producing the possibility that electronic components of the card and an apparatus are adversely affected.  
           [0014]    The above-mentioned prior art examples similarly have this problem. Particularly, the technique disclosed in the other prior art example of Japanese Patent Application Laying-Open No. 2002-134224 cannot solve the problem because of the following reason. The card is prevented from being accidentally ejected by engaging the elastic lock piece with the card in the card set position, the elastic lock piece is disposed on the slider. When the locked state of the slider at the pushed position is once canceled, therefore, the card also is ejected together with the slider.  
           [0015]    The invention has been conducted in view of the above-discussed problem. It is an object of the invention to provide a card connector in which, even when only a simple countermeasure such as a slight modification of a cam mechanism is taken, accidental ejection of a card due to a drop impact or the like hardly occurs.  
           [0016]    The card connector of the invention comprises: a slider which is longitudinally movably attached to a case forming a card insertion space, the slider being to be pushed by a card which is inserted into the card insertion space, to be moved from a standby position to a pushed position corresponding to a card set position, the slider being resiliently urged at the pushed position in a direction of ejecting the card; and a cam mechanism having functions of locking the slider to the pushed position, and canceling the locked state where the slider is locked to the pushed position. The cam mechanism has: an engagement pin attached to one of the case and the slider; and a cam body disposed on another one of the case and the slider, and comprising a loop groove into which an engagement end of the engagement pin is relatively displaceably fitted. The loop groove of the cam body comprises: a protruding engagement portion which is to be engaged with the engagement end that has passed through a forward path of the loop groove, thereby locking the slider to the pushed position corresponding to the card set position; an escape path which, when the slider at the pushed position is further pushed, allows the engagement end to escape from a position of engagement with the engagement portion to a start portion of a return path of the loop groove; and a stepped surface which, when the slider is to be retracted, is engaged with the engagement end that escapes to the start portion of the return path, to block the engagement end from reversely moving, thereby retaining the engagement end in the return path. The engagement end is elastically pressed against a bottom face of the escape path. The above configuration is identical with that of the conventional example shown in FIGS. 12 and 13.  
           [0017]    In the invention, the above configuration is further provided with a configuration in which the bottom face of the escape path has an inclined surface of a rising gradient which is directed toward an upper edge of the stepped surface.  
           [0018]    As described above, the configuration in which the bottom face of the escape path has a rising inclined surface which is directed toward an upper edge of the stepped surface is added. When the engagement end of the engagement pin moves from the position of engagement with the engagement portion to the return-path start portion along the escape path, therefore, the rising inclined surface provides the engagement end which slidingly moves while being elastically pressed against the inclined surface, with a resistance (movement resistance), so that the engagement end hardly escapes from the engagement position to the return-path start portion by a reaction due to a drop impact or the like. As a result, a situation where the engagement end is disengaged from the engagement portion because of a drop or the like to cancel the locked state of the slider hardly occurs, and also a situation where the card which has been positioned to the card set position is accidentally ejected hardly occurs.  
           [0019]    In the invention, at the position of engagement of the engagement end with the engagement portion, the loop groove may be formed at a depth which is equal to a depth of the return-path start portion, or at a depth which is larger than a depth of the return-path start portion. In the configuration in which the depth of the loop groove at the engagement position is equal to that of the return-path start portion, as compared with that shown in FIG. 12 in which the depth of the loop groove at the engagement position a is smaller than that of the return-path start portion  23   a,  the engagement width of the engagement end  41  with respect to the engagement portion  24  is larger, and hence a situation where the engagement end  41  passes over the engagement portion  24  hardly occurs, with the result that the stability of the locked state of the slider at the pushed position is improved. When the depth of the loop groove at the engagement position a is equal to that at the return-path start portion  23   a,  the engagement position a becomes equal to the return-path start portion  23   a  which is the deepest portion in the conventional example shown in FIGS. 12 and 13, and hence the other portions of the loop groove  21  can be made shallower. According to the configuration, in the case where the cam body  20  is molded integrally with the slider  70 , when the loop groove  21  is made shallower, the slider  70  can be easily thinned. By contrast, in the configuration where the depth of the loop groove at the engagement position is larger than that of the return-path start portion, the rising gradient of the inclined surface is larger than that in the case where the depths are equal to each other. Therefore, the movement resistance on the inclined surface when the engagement end moves along the escape path to enter the return-path start portion is large. As a result, the engagement end hardly escapes from the engagement position to the return-path start portion by a reaction due to a drop impact or the like, and a situation where the engagement end is disengaged from the engagement portion because of a drop or the like to cancel the locked state of the slider hardly occurs. Moreover, also a situation where the card which has been positioned to the card set position is accidentally ejected hardly occurs.  
           [0020]    In the invention, preferably, the upper edge of the stepped surface is divided into one edge which elongates along a bottom face of the return-path start portion, and another edge of a falling gradient which elongates from an end of the one edge toward a root of the engagement portion, and the inclined surface is divided into one inclined surface of a rising gradient which extends toward the one edge, and another inclined surface of a rising gradient which extends toward the other edge. Preferably, a base of the other inclined surface crosses the escape path, and a base of the one inclined surface is positioned on a step-like wall face which is opposed to the engagement portion to form the escape path. According to the invention, in the case where a single flat rising inclined surface is formed in the escape path, the rising gradient of the other inclined surface is larger than that of the single rising inclined surface. Therefore, the movement resistance on the other inclined surface when the engagement end moves along the escape path to enter the return-path start portion is large. As a result, the engagement end hardly escapes from the engagement position to the return-path start portion by a reaction due to a drop impact or the like, and a situation where the engagement end is disengaged from the engagement portion because of a drop or the like to cancel the locked state of the slider hardly occurs. Moreover, also a situation where the card which has been positioned to the card set position is accidentally ejected hardly occurs. The functions of the invention will be described in more detail with reference to the following embodiment.  
           [0021]    In the invention, preferably, the case has a body, and a sheet metal cover which is attached to the body, and a spring piece which is formed by inwardly stamping and raising the cover is in elastic contact with the engagement pin, whereby the engagement end is elastically pressed against the bottom face of the escape path. According to the configuration, an additional component(s) for elastically pressing the engagement end against the bottom face of the escape path is not required.  
           [0022]    According to the invention, although only a simple countermeasure that the configuration of the cam mechanism, or specifically the shape of the bottom face of the escape path in the cam body is slightly changed is taken, an effect that accidental ejection of a card due to a drop impact or the like hardly occurs can be attained without impairing the card insertion operability. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    [0023]FIG. 1 is a schematic perspective view of a card connector of an embodiment of the invention;  
         [0024]    [0024]FIG. 2 is a partially cutaway plan view showing a state where a card is half locked to a slider at a standby position;  
         [0025]    [0025]FIG. 3 is a partially cutaway plan view showing a state where the slider is pushed to a pushed position;  
         [0026]    [0026]FIG. 4 is a partially cutaway plan view showing a state where a first pushing operation is conducted;  
         [0027]    [0027]FIG. 5 is a plan view of the slider;  
         [0028]    [0028]FIG. 6 is a perspective view of main portions of a cam body;  
         [0029]    [0029]FIG. 7 is a plan view of main portions of a cam mechanism;  
         [0030]    [0030]FIG. 8 is a section view taken along the line VIII-VIII of FIG. 7;  
         [0031]    [0031]FIG. 9 is a view illustrating a portion where an engagement pin is coupled to a body;  
         [0032]    [0032]FIG. 10 is a perspective view showing the shape of an inclined surface;  
         [0033]    [0033]FIG. 11 is a perspective view showing the shape of the inclined surface in a modification;  
         [0034]    [0034]FIG. 12 is a schematic perspective view showing a cam body of a cam mechanism employed in a conventional card connector; and  
         [0035]    [0035]FIG. 13 is a longitudinal side section view showing main portions of a cam mechanism  10  comprising the cam body of FIG. 12. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0036]    [0036]FIG. 1 is a schematic perspective view of a card connector of an embodiment of the invention, FIG. 2 is a partially cutaway plan view showing a state where a card  100  is half locked to a slider  70  at a standby position, with omitting a cover  55  of a case  50 , FIG. 3 is a partially cutaway plan view showing a state where the slider  70  is pushed to a pushed position by the card  100 , with omitting the cover  55  of the case  50 , FIG. 4 is a partially cutaway plan view showing a state where a first pushing operation is conducted on the card  100 , with omitting the cover  55  of the case  50 , FIG. 5 is a plan view of the slider  70 , FIG. 6 is a perspective view of main portions of a cam body  20 , FIG. 7 is a plan view of main portions of a cam mechanism  10 , FIG. 8 is a section view taken along the line VIII-VIII of FIG. 7, FIG. 9 is a view illustrating a portion where an engagement pin  40  is coupled to a body  51 , FIG. 10 is a perspective view showing the shape of an inclined surface  32 , and FIG. 11 is a perspective view showing the shape of the inclined surface  32  in a modification.  
         [0037]    As shown in FIG. 1, the card connector has a case  50  comprising: a body  51  formed by a molded product of a synthetic resin; and a sheet metal cover  55  which is attached to the body  51 . A card insertion space which is surrounded by the body  51  and the cover  55 , and which comprises a card insertion port (slot) is formed inside the case  50 . As shown in FIG. 2, a large number of contacts  57  are laterally arranged in a front end portion of the body  51 . The contacts  57  are in elastic contact with terminals of the card  100  which is inserted into the card insertion space to reach a card set position, thereby making electrical connections therebetween. The body  51  further comprises a rib-like projection  50   a  for preventing a card from being erroneously inserted. As shown in FIGS. 3 and 4, when the card  100  in an adequate posture is inserted into the card insertion space, the projection  50   a  is accommodated in a groove  130  formed in the card  100 . By contrast, when the card  100  in an inverted posture is inserted into the card insertion space, the projection  50   a  bumps against the tip end of the card  100 , thereby preventing the card  100  from being erroneously inserted.  
         [0038]    As shown in FIGS.  2  to  4 , the slider  70  is placed inside the case  50 , and always rearward urged by a spring member  52  configured by a coil spring. When the rear end of the slider  70  butts against a projection  53  of the rear end of the body  51 , the slider  70  is positioned to the standby position. As shown in FIG. 5, the slider  70  comprises an inward protrusion  71  in a front end portion. The protrusion  71  receives a front end corner  110  of the card  100  which is inserted into the card insertion space of the case  1  as shown in FIG. 2. A cantilevered elastic piece  76  which has a mountain-like engaging portion  75  at the tip end is molded integrally with the slider  70 .  
         [0039]    As seen from FIGS.  5  to  8 , the cam mechanism  10  comprises an engagement pin  40  which is formed by bending an elastic wire member into a low-profile portal shape. In contrast to the cam body  20  which is molded integrally with the slider  70  as shown in FIG. 5, a rear end leg  42  of the engagement pin  40  is rotatably fittingly supported by a support hole  54  (see FIGS.  2  or  3 ) which is formed in the projection  53  of the body  51  as shown in FIG. 9. A front end portion of the engagement pin  40  is formed as an engagement end  41 .  
         [0040]    A loop groove  21  of the cam body  20  is formed into a generally similar shape as the loop groove which has been described with reference to FIG. 11. Specifically, as shown in FIGS. 6 and 7, the loop groove  21  comprises: a forward path  22 ; a return path  23 ; a protruding engagement portion  24  which is formed between the paths; a lead-in path  25  which elongates from a forward-path end portion  22   a  to the engagement portion  24 ; and an escape path  26  which elongates from the engagement portion  24  to a return-path start portion  23   a.  The loop groove  21  is formed into a slender heart shape as a whole, and the lead-in path  25  and the escape path  26  form a heart-shape recess. When the engagement end  41  of the engagement pin  40  is fitted into the loop groove  21  and the slider  70  is positioned at the standby position, the engagement end  41  is positioned at an initial position which coincides with a junction  27  of the start portion of the forward path  22  and the end portion of the return path  23  as shown in FIG. 2. A spring piece  56  which is formed by inwardly stamping and raising the cover  55  is placed on the engagement pin  40 . The engagement end  41  of the engagement pin  40  is always elastically pressed against the bottom face of the loop groove  21  by the elasticity of the spring piece  56 .  
         [0041]    In this configuration, when the front end corner  110  of the card  100  which is inserted in an adequate posture into the card insertion space as shown in FIG. 2 rides over the mountain-like engaging portion  75  of the slider  70  that is retracted to the standby position by the spring member  52 , the mountain-like engaging portion  75  is fitted into a recess  120  formed in the card  100 . This state is a half-locked state of the card  100 . In the half-locked state, the card  100  is prevented from being freely extracted, by the engagement of the recess  120  with the mountain-like engaging portion  75 , and, when a pulling force of a certain degree is applied to the card  100 , the card  100  is caused to ride over the mountain-like engaging portion  75  and then pulled out.  
         [0042]    When a first pushing operation is applied on the card  100  in the state of FIG. 1, the cam body  20  is pushed together with the slider  70  by the card  100  against the urging force A of the spring member  52 , and the engagement end  41  of the engagement pin  40  moves along the forward path  22  with starting from the junction  27  of the loop groove  21  to reach the forward-path end portion  22   a  (the position of the slider  70  at this timing is shown in FIG. 4). When the pushing force is canceled at this timing, the cam body  20  is pushed back together with the slider  70  by the urging force A, so that the engagement end  41  moves along the lead-in path  25  and is then engaged with the engagement portion  24  as shown in FIGS. 7 and 8 (the position of the slider  70  at this timing is shown in FIG. 3). When a second pushing operation is then applied on the card  100 , the cam body  20  is pushed together with the slider  70  against the urging force A, and the engagement end  41  moves along the escape path  26  to reach the return-path start portion  23   a.  When the pushing force is canceled at this timing, the cam body  20  is pushed back by the urging force A, so that the engagement end  41  moves along the return path  23  and then returns to the junction  27 .  
         [0043]    As a result of the push-push operation, the insertion of the card  100  to the card set position, and the ejection from the card set position are conducted. In the first card pushing operation, the slider  70  is pushed from the standby position to the pushed position corresponding to the card set position, and the engagement end  41  is engaged with the engagement portion  24  to lock the slider  70  to the pushed position, whereby the card  100  which is half locked to the slider  70  is positioned to the card set position, and terminals of the card are in contact with contacts disposed on the body  51  so as to make electrical connections therebetween. By contrast, in the second card pushing operation, the engagement end  41  moves along the escape path  26  and is then disengaged from the engagement portion  24 , and hence the locked state of the slider  70  is canceled. Thereafter, the engagement end  41  returns through the return path  23  to the junction  27 , whereby the card is ejected.  
         [0044]    In the embodiment, as shown in FIGS.  6  to  8  and  10 , the bottom face of the escape path  26  of the loop groove  21  of the cam body  20  comprises the inclined surface  32  of a rising gradient which is directed toward an upper edge of a stepped surface  31  that is located in the boundary between the escape path  26  and the return-path start portion  23   a.  In the embodiment, as shown in FIG. 10, the upper edge of the stepped surface  31  is divided into one edge  33  which is parallel to the bottom face of the horizontal return-path start portion  23   a,  and another edge  34  of a falling gradient which elongates from an end of the one edge  33  toward the root of the engagement portion  24 , and the inclined surface  32  is divided into one inclined surface  32   a  of a rising gradient which extends toward the one edge  33 , and another inclined surface  32   b  of a rising gradient which extends toward the other edge  34 . A base  32   b ′ of the other inclined surface  32   b  crosses the escape path  26 , and a base  32   a ′ of the one inclined surface  32   a  is positioned on a step-like wall face  35  which is opposed to the engagement portion  24  to form the escape path  26 .  
         [0045]    In the configuration where the bottom face of the escape path  26  comprises the rising inclined surface  32  which is directed toward the upper edge of the stepped surface  31 , when the engagement end  41  which is engaged with the engagement portion  24  as shown in FIG. 8 moves from the engagement position a along the escape path  26  (see FIGS.  6  or  10 ) to the return-path start portion  23   a,  the rising inclined surface  32  provides the engagement end  41  which slidingly moves while being elastically pressed against the inclined surface  32  by the urging of the spring piece  56 , with a movement resistance. In addition, the urging force A generated by the spring member  52  acts on the slider  70 . Therefore, the engagement end  41  hardly escapes from the engagement position a to the return-path start portion  23   a  by a reaction due to a drop impact or the like. As a result, a situation where the engagement end  41  is disengaged from the engagement portion  24  because of a drop or the like to cancel the locked state of the slider  70  hardly occurs, and also a situation where the card  100  which has been positioned to the card set position is accidentally ejected hardly occurs.  
         [0046]    In the embodiment, at the position a of engagement of the engagement end  41  with the engagement portion  24 , the loop groove  21  is formed at a depth which is larger than that of the return-path start portion  23   a.  At the position a of the engagement of the engagement end  41  with the engagement portion  24 , the depth of the loop groove  21  may be formed so as to be equal to that of the return-path start portion  23   a.  When the depth of the loop groove  21  at the engagement position a is made larger than that of the return-path start portion  23   a,  however, the rising gradients of the one inclined surface  32   a  and the other inclined surface  32   b  are larger than those in the case where the depths are equal to each other, and hence the movement resistances on the inclined surfaces  32   a,    32   b  which are exerted when the engagement end  41  moves along the escape path  26  to the return-path start portion  23   a  are large. Therefore, the engagement end  41  hardly escapes from the engagement position a to the return-path start portion  23   a  by a reaction due to a drop impact or the like. As a result, a situation where the engagement end  41  is disengaged from the engagement portion  24  because of a drop or the like to cancel the locked state of the slider  70  very hardly occurs, and also a situation where the card  100  which has been positioned to the card set position is accidentally ejected very hardly occurs. In the configuration in which the depth of the loop groove  21  at the engagement position a is larger than that of the return-path start portion  23   a,  the engagement width of the engagement end  41  with respect to the engagement portion  24  is large, and hence a situation where the engagement end  41  slides over the engagement portion  24  hardly occurs, with the result that the stability of the locked state of the slider at the pushed position is improved. By contrast, in the configuration in which the depth of the loop groove  21  at the engagement position a is equal to that at the return-path start portion  23   a,  the engagement position a is equal to the return-path start portion  23   a  which is the deepest portion in the conventional example shown in FIGS. 12 and 13, and hence the depths of other portions of the loop groove  21  can be made small. When the loop groove  21  is made shallow, therefore, the slider  70  with which the cam body  20  is integrally molded can be easily thinned.  
         [0047]    In the embodiment, the upper edge of the stepped surface  31  is divided into the one edge  33  which is parallel to the bottom face of the horizontal return-path start portion  23   a,  and the other edge  34  of a falling gradient which elongates from the end of the one edge  33  toward the root of the engagement portion  24 , and the inclined surface  32  is divided into the one inclined surface  32   a  of a rising gradient which extends toward the one edge  33 , and the other inclined surface  32   b  of a rising gradient which extends toward the other edge  34 . By contrast, as in a modification shown in FIG. 11, the rising inclined surface  32  which is directed toward the upper edge of the stepped surface  31  may be formed by a single flat surface. In the configuration of FIG. 10 in which the inclined surface  32  is divided into the one inclined surface  32   a  and the other inclined surface  32   b,  as compared with that of FIG. 11 in which the inclined surface  32  is formed by the single flat surface, the rising gradient of the other inclined surface  32   b  is larger than that of the inclined surface  32  of FIG.  11 , and hence the movement resistance on the other inclined surface  32   b  which is exerted when the engagement end  41  moves along the escape path  26  to the return-path start portion  23   a  is large. Therefore, the locked state of the slider  70  is hardly cancelled by a reaction due to a drop impact or the like.  
         [0048]    As in the configuration of FIG. 10 in which the other edge  34  of the upper edge of the stepped surface  31  is inclined toward the root of the engagement portion  24 , or that of FIG. 11 in which the upper edge of the stepped surface  31  is inclined toward the root of the engagement portion  24 , the operation of the engagement end  41  in which the end moves from the escape path  26  to the return-path start portion  23   a  while sliding over the stepped surface  31  can be smoothly conducted although the configuration can generate the above-mentioned movement resistance. Abnormal noises are hardly produced when the end slides over the stepped surface.  
         [0049]    In the above, the embodiment in which the cam body  20  of the cam mechanism  10  is placed on the slider  70 , and the engagement pin  40  is placed on the case  50  has been described. Alternatively, the cam body may be placed on the case, and the engagement pin may be placed on the slider. In the above, the mountain-like engaging portion  75  which is used for half locking the card  100  inserted into the card insertion space is disposed on the cantilevered elastic piece  76  which is molded integrally with the slider  70 . Alternatively, a tip end portion of a spring piece which is an additional component attached to the slider may be bent into a mountain-like shape so as to function as the mountain-like engaging portion.  
         [0050]    In FIGS.  1  to  13 , identical or corresponding components are denoted by the same reference numerals.