Patent Publication Number: US-8112850-B2

Title: Buckle

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a buckle provided with a male member and a female member. More specifically, it relates to a buckle that connects and disconnects both ends of a cord or two cords with each other. 
     2. Description of Related Art 
     A buckle disclosed in Japanese Utility Model No. 2594412 is known as a means to connect and disconnect both ends of a cord or two cords with each other. 
     This buckle is provided with an insertion body mounted on one of members that are to be connected with each other and a buckle body mounted on the other. The insertion body includes a pair of legs inserted into the buckle body and an engaging portion provided on each of distal ends of the pair of the legs. The buckle body is provided with an accommodating portion where the leg is inserted and an engaged portion that engages with the engaging portion of the leg. 
     The engaging portion of the insertion body and the engaged portion of the buckle body are engaged at engaging surfaces that have the same slant surfaces. 
     In other words, as shown in  FIGS. 12A and 12B , an engaging surface  112  that inclines toward the inserting direction gradually from the outside to the inside is provided on an engaging portion  111  of an insertion body  110  at the rear end surface of the inserting direction of the insertion body  110 . An engaged surface  122  that inclines toward the inserting direction gradually from the outside to the inside is formed on an engaged portion  121  of a buckle body  120  at the front end surface of the inserting direction of the insertion body  110 . 
     Thus, when the insertion body  110  is inserted in the buckle body  120 , the engaging portion  111  of the leg  113  abuts to the engaged portion  121  so that the leg  113  is elastically deformed inward (see the condition in  FIG. 12A ). When the insertion body  110  is further inserted into the buckle body  120  so that the engaging portion  111  goes over the engaged portion  121 , the leg  113  is elastically deformed outward so that the engaging surface  112  is engaged with the engaged surface  122  (see the condition in  FIG. 12B ). Accordingly, the insertion body  110  is engaged with the buckle body  120 . 
     In the buckle disclosed in Japanese Utility Model No. 2594412, in the condition in  FIG. 12B , when the tensile force (i.e., the force in a direction opposite to the inserting direction) is applied on the insertion body  110  and the buckle body  120 , the engaging intensity between the insertion body  110  and the buckle body  120  can be enhanced since the engaging surface  112  and the engaged surface  122  are slanted. However, shakiness is generated between the insertion body  110  and the buckle body  120  under the condition where the insertion body  110  is engaged with the buckle body  120 . 
     In other words, the insertion body  110  needs to be inserted until the position where the engaging portion  111  goes over the engaged portion  121  in order for the engaging portion  111  to be engaged with the engaged portion  121 . Once the engaging portion  111  goes over the engaged portion  121 , the leg  113  is elastically deformed outward and the engaging surface  112  and the engaged surface  122  are engaged with each other at a position where the insertion body is slightly returned in a releasing direction. Accordingly, the inserting direction dimension L that corresponds to the slant of the engaging surface  112  and the engaged surface  122  becomes a factor that generates shakiness between the insertion body  110  and the buckle body  120 . Such shakiness causes an impact noise and harms the quality thereof. 
     SUMMARY OF VARIOUS EMBODIMENTS OF THE INVENTION 
     An object of various embodiments of the invention is to provide a buckle that solves the above problems and prevents shakiness between a male member and a female member. 
     A buckle according to one embodiment of the present invention includes: a male member and a female member, in which: the male member includes: a base; a pair of legs that project from the base; and an engaging portion provided on a distal end of each of the pair of the legs to be engageable with the female member; the female member includes: an insertion port into which the pair of the legs of the male member are inserted; a guide that elastically deforms the pair of the legs inserted through the insertion port in a direction in which the distal ends of the pair of the legs come closer to each other; and a pair of engaged portions that displaces the distal ends of the pair of the legs in a direction in which the distal ends of the pair of legs are spaced apart from each other to be engaged with each of the engaging portions when the male member is inserted to a predetermined position; each of the engaged portions are oppositely provided in the direction for the legs to be spaced apart from each other, the engaged portions respectively have an abutment wall that abuts each of the engaging portions; and the abutment walls are respectively formed as a wall surface that extends in a direction in which each of the walls comes closer to each other toward a releasing direction of the male member. 
     In the above, a slant surface (tapered surface) and an arc may be, for example, used to form each of the abutment walls as a wall surface that extends in the direction in which the wall surface comes closer to each other toward a releasing direction of the male member. 
     According to the above arrangement, when the pair of the legs of the male member are inserted through the insertion port, the guide elastically deforms the distal ends of the pair of the legs in the direction in which the distal ends come closer to each other. Once the male member is inserted to the predetermined position, each of the engaging portions is moved in the direction to be away from each other by elastic recovering force of the pair of the legs to be abutted each of the abutment walls oppositely disposed in the direction to be away from each other. 
     Each of the abutment walls is formed as a wall that extends in the direction in which the abutment walls come closer to each other toward the releasing direction of the male member (e.g. the abutment wall of the engaged portion for the engaging portion to be abutted is formed as a slant surface), the engaging portions can be securely contacted with the engaged portions. Accordingly, since no clearance is generated between the engaging portion and the engaged portion, shakiness caused by the clearance can be prevented. 
     At this time, since each of the engaging portions abuts each of the abutment walls while being urged in the direction to be away from each other by the elastic restoring force of each of the legs and each of the abutment walls are formed as walls that extend in the direction in which each of the abutment walls come closer to each other toward the releasing direction of the male member, no clearance is generated in the inserting direction of the male member and in a direction orthogonal to the inserting direction of the male member in which the pair of the legs elastically deform. Therefore, shakiness in these two directions can be prevented. 
     Further, since each of the engaging portions abut each of the abutment surfaces while being urged in a direction to be away from each other (i.e. each of the engaging portions abuts on the walls that extend in the direction in which each of the engaging portions come closer to each other toward the releasing direction of the male member), resistance against the releasing direction of the male member can be generated to maintain the engaging force between the male member and the female member. 
     In the above arrangement, an abutment portion of the engaging portion which abuts to each of the abutment walls may preferably extend in a direction in which the abutment portion comes closer to each other toward the releasing direction of the male member and is formed as a wall surface that substantially coincides with the wall surface of each of the abutment walls. 
     In the above, since the abutment portion of the engaging portion which abuts on each of the abutment walls is also formed as a wall surface that substantially coincides with the wall surface of each abutment wall, the abutment wall of the engaged portion and the abutment portion of the engaging portion can be brought into face-to-face contact to maintain the resistance against the releasing direction of the male member. Thus, the engaging force between the male member and the female member can also be kept higher. 
     In the above arrangement, each of the engaged portions may include an engaged wall that is consecutively formed on a side of the insertion port of the abutment wall and substantially orthogonal to the inserting direction of the male member; and each of the engaging portions may preferably include an engaging wall that is consecutively formed on an end of the base side of the abutment portion, substantially orthogonally crosses with respect to the releasing direction of the male member and is engaged with the engaged wall. 
     In this arrangement, when a force of releasing direction affects the male member and the female member while the male member and the female member are engaged with each other, the abutment portion of the engaging portion is moved along the slant surface of the abutment wall of the engaged portion so that the engaging wall of the engaging portion is engaged with the engaged wall of the engaged portion. 
     Since the engaging wall of the engaging portion and the engaged wall of the engaged portion are formed as walls substantially orthogonal to the inserting direction of the male member, the force in the releasing direction applied on the male member and the female member can be securely absorbed by these engaging wall and the engaged wall. Thus, the male member and the female member are not easily disengaged by the force of the releasing direction applied on the male member and the female member. 
     In the above arrangement, a butting portion whose central portion more projects toward a projecting direction of the legs than both side portions where the legs project may preferably be provided on the base of the male member; and a butting portion that is provided on a side of the insertion port to closely contact with the butting portion of the male member is provided on the female member. 
     In the above, when the male member is inserted in the female member, the butting portion of the male member closely touches with the butting portion of the female member, which results in a simple design and less shakiness. 
     A buckle according to another embodiment of the invention includes: a male member; and a female member, where the male member comprises: a base; a pair of legs that project from the base; an engaging portion provided on a distal end of each of the pair of the legs to be engageable with the female member; and an elastic connecting code connected between inner sides of the pair of the legs; the female member comprises: an insertion port into which the pair of the legs of the male member are inserted; and a pair of engaged portions that are engaged with each of the engaging portions when the pair of the legs inserted through the insertion port are inserted to a predetermined position; the base is provided by a frame including a cord attachment hole therein, a central portion of a frame material of the frame on which the pair of legs are provided is protruded in a direction for the pair of the legs are protruded relative to both ends thereof, and a central portion of the connection code is convexly curved toward the frame material. 
     In the buckle according to the above embodiment of the invention, the frame material is preferably provided as a butting portion against the female member and the butting portion is preferably formed in a V-shape in which a central portion of the frame material protrudes in the projecting direction of the leg relative to the both ends of the frame material. 
     In the buckle according to the above embodiment of the invention, the connection code is preferably formed in a reverse U-shape of which central portion is curved in a convex shape toward the frame material. 
     When a male member has a base including a cord attachment hole therein and a pair of legs protruding from the base as in a conventional buckle, since the opening of the cord attachment hole is small, it is difficult to insert a cord into the cord attachment hole. Further, when a tensile force is applied on the pair of legs (e.g. when external force for biasing the pair of legs outward or when a foreign material enters in between the pair of legs to deform the pair of legs outward), the legs are likely to be damaged. 
     According to the above embodiment of the invention, since the base includes the frame having a cord attachment hole thereinside and the frame material of the frame provided with the leg is protruded in the projecting direction of the legs at the center thereof relative to both ends, the opening of the cord attachment hole within the frame can be widened, which facilitates inserting operation of the cord into the cord attachment hole. 
     Further, since the inner sides of the pair of legs are connected by the elastic connecting code, unexpected deformation of the pair of legs toward the outside can be avoided, which prevents deformation of the legs when excessive tensile force (tensile force toward the outside) is applied on the legs. Further, since the connecting code is convexly curved in a direction for the central portion thereof to come close to the frame material of the base, i.e. since the space between the central portion of the frame material and the central portion of the connecting code is narrowed, foreign material is not likely to enter into the space, which prevents invasion of the foreign material into the space to deform the legs toward the outside. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a buckle of an embodiment of the present invention. 
         FIG. 2  is an exploded perspective view showing the disengaged buckle of the embodiment. 
         FIG. 3A  is a partially-sectional plan view showing the disengaged buckle of the embodiment. 
         FIG. 3B  is a partially-sectional perspective view of the female member of the embodiment. 
         FIG. 4  is an enlarged view showing a part around an engaging portion of a male member in the embodiment. 
         FIG. 5  is an enlarged cross-section taken along V-V line in  FIG. 3A . 
         FIG. 6  is an enlarged view showing a part around an engaged portion of a female member in the embodiment. 
         FIG. 7  is a cross-section showing a condition where the male member is in the middle of being inserted into the female member in the embodiment. 
         FIG. 8  is a cross-section showing a condition where the male member has been inserted into the female member in the embodiment. 
         FIG. 9  is a view showing a condition where a tensile force is applied on the male member and the female member in the embodiment. 
         FIG. 10  is an exploded view showing a modification of a part around the engaged portion of the female member. 
         FIG. 11  is a cross-section showing another modification of the female member. 
         FIG. 12A  is a view showing a disadvantage of a conventional buckle. 
         FIG. 12B  is a view showing a disadvantage of the conventional buckle. 
     
    
    
     DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION 
     An embodiment of the present invention will be described below with reference to drawings. 
       FIG. 1  is a perspective view showing a buckle of the embodiment.  FIG. 2  is a perspective view showing the disengaged buckle of the embodiment.  FIG. 3A  is a partially-sectional plan view showing the disengaged buckle of the embodiment.  FIG. 3B  is a partially-sectional perspective view of the female member. 
     As shown in FIGS.  1 - 3 A,B, a buckle  1  of the present embodiment is for connecting and disconnecting end portions  2  and  3  of a cord, which is provided with a male member A integrally molded of synthetic resin and a female member B similarly integrally molded of synthetic resin into which the male member A is inserted to be engaged. Materials of the male member A and the female member B are not limited to synthetic resin but may be other material such as metal. 
     The male member A is provided with: a base  10 ; a pair of legs  20  that project from the both sides in the width direction (a direction orthogonally crossing the inserting direction of the male member A) of the base  10  toward the length direction (the inserting direction of the male member A) in parallel with each other; and are elastically deformable in directions where the pair of the legs  20  come closer or get apart with each other and an engaging portion  30  provided on each distal end of the pair of the legs  20  and engageable with the female member B. 
     The base  10  is constituted by a substantially pentagonal frame  12  that has a cord attachment hole  11  (a cord attachment portion) where the end portion  2  of the cord is inserted to be engaged at an inner central position. 
     A connecting bar  13  is built across the width direction of the frame  12  at the middle position of the cord attachment hole  11 . The connecting bar  13  devides the cord attachment hole  11  into two cord attachment holes  11 A and  11 B respectively provided on the front end of the inserting direction (an end provided with the legs  20 ) and on the opposed rear end of the inserting direction. Accordingly, the length of the cord can be adjusted by inserting the cord into the cord attachment holes  11 A and  111 B to wind around the connecting bar  13 . 
     The cord attachment hole  11 A exhibits substantially pentagonal shape that extends toward the projecting direction of the pair of legs  20  while gradually decreasing width dimension (i.e. dimension in a direction orthogonal to the projecting direction of the leg  20 ) thereof. 
     Of the frames  12 , a frame material  12 A on which the legs  20  are provided is formed as a butting portion  14  that butts the female member B. The butting portion  14  is formed in a V-shape in which the center portion projects further toward the projecting direction of the legs  20  than the both ends of the frame material  12 A. The butting portion  14  has a fitting convex  15  which has a slightly smaller profile than the outer circumferential profile of the frame material  12 A and slightly projects in the projecting direction of the legs  20  on the surface on which the legs  20  of the frame material  12 A is provided. 
     Each of the legs  20  includes an elastic piece  21  that linearly extends in the inserting direction of the male member A from each side of the base  10  and is elastically deformable in directions where both of the elastic pieces  21  come closer or get apart with each other and a guide piece  22  that extends from the distal end of the elastic piece  21  in the inserting direction of the male member A. 
     The elastic piece  21  has a cross-section in which the dimension (width dimension) in the elastically deforming direction is smaller than that of the front-back direction. 
     The guide piece  22  is bifurcated from the elastic piece  21  and jointed at the distal end while the outer surface of the guide piece  22  is curved inward toward the distal end (i.e. the direction in which each of the legs  20  come closer to each other). An elastic connecting cord  23  connects each of the inner surfaces of a pair of the guide pieces  22 . The connecting cord  23  is reversed-U-shaped component that convexly curves toward the frame material  12 A to prevent the pair of the guide piece  22  from deforming more outward than a predetermined level so that the legs  20  are protected from damages generated by an excessive tensile force (tensile force to the outside) imposed on the legs  20 . 
     The engaging portion  30  is constituted by a projection  31  that projects toward the top and bottom sides of the distal end of the guide piece  22  of each of the pair of the legs  20 . 
     The projection  31  includes, as shown in  FIG. 4 , peripheral walls such as an inner side wall  31 A, a front side wall  31 B, a front outer side wall  31 C, a back outer side wall  31 D and a back side wall  31 E while being substantially pentagonal in which corner portions of neighboring walls are connected by circular surfaces. The inner side wall  31 A is positioned on the inner surface of the guide piece  22  and formed as a wall substantially parallel to the inserting direction of the male member A. The front side wall  31 B is formed as a wall substantially orthogonally crossing the inserting direction of the male member A. The front outer side wall  31 C is formed as a slant surface gradually distanced from the inner side wall  31 A toward the releasing direction of the male member A from the front side wall  31 B. The back outer side wall  31 D is formed as a slant surface that comes gradually closer to the inner side wall  31 A toward the releasing direction of the male member A from the front outer side wall  31 C. More specifically, the slant surface is formed to make 45-degree angle relative to the inner side wall  31 A. The front outer side wall  31 C and the back outer side wall  31 D are positioned on the opposite side of the inner side wall  31 A (i.e. on the outer surface side of the guide piece  22 ). The back side wall  31 E is a surface that faces back and forth to the front side wall  31 B in the inserting direction of the male member A, which is formed as a wall substantially orthogonally crossing with respect to the inserting direction of the male member A. 
     In other words, each of a pair of the projections  31  is substantially pentagonal, which includes the back outer side wall  31 D (abutment wall) formed on the slant surface that inclines toward the direction in which both of the projections  31  come closer and the back side wall  31 E (engaging wall) substantially orthogonally crossing with the inserting direction of the male member A and consecutively formed from the end of the base  10  side of the back outer side wall  31 D. 
     The female member B is provided with, as shown in  FIG. 5 , a flat cylindrical female member body  40  that includes a top wall  40 A and a bottom wall  40 B which constitute the top and bottom surfaces and a pair of side walls  40 C that connect the top wall  40 A and the bottom wall  40 B. 
     An insertion port  41  in which the pair of the legs  20  of the male member A is inserted and a butting portion  42  that butts the butting portion  14  of the male member A are provided on a first end of the female member body  40 . The butting portion  42  is formed in V-shape that corresponds to the butting portion  14  of the male member A and the insertion port  41  is formed to fit with the fitting convex  15  of the male member A. 
     A cord attachment hole  43  and a connecting bar  44  (cord attachment portions) where the end portion  3  of the cord is inserted and engaged are formed on a second end of the female member body  40 . An opening  45  concavely cut out toward the inside of the top wall  40 A and the bottom wall  40 B is formed at the middle portion of the side wall  40 C. Each of the guide pieces  22  provided on each of the legs  20  of the male member A is exposed from the opening  45  so that both of the guide pieces  22  can be operably pushed inward with each other. In other words, the guide piece  22  also works as an operating portion that releases the male member A from the female member B. 
     A guide  50  that is formed from the insertion port  41  toward the inside of the female member body  40  and elastically deforms each of the distal ends of the pair of the legs  20  in the direction in which each of the distal ends come closer to each other while guiding the engaging portion  30  and a pair of engaged portions  60  provided on the both sides of the rear side of the guide  50  to be engaged with each of the engaging portions  30  are provided on the inside of the female member body  40 . 
     The guide  50  is constituted by a tapered guide groove  50 A whose width becomes gradually narrower from the insertion port  41  to the engaged portion  60  at the inner surface of the top wall  40 A and the bottom wall  40 B of the female member body  40 . 
     The engaged portion  60  is formed by a concave  61  that shifts each of the engaging portions  30  to the direction in which the engaging portions get apart with each other. 
     The concave  61  is, as shown in  FIG. 6 , formed as a substantially pentagonal concaved groove formed by cutting the inner surfaces of the top wall  40 A and the bottom wall  40 B of the male member body  40  from the rear portion of the guide groove  50 A toward a substantially orthogonally crossing direction with respect to the inserting direction of the male member A to the both outsides. In other words, a butting wall of the concave  61  is placed on the rear portion in the releasing direction of each engaging portion  30 . The concave  61  is substantially pentagonal including an abutment wall  61 D on the butting wall on which each engaging portion  30  abuts and an engaged wall  61 E consecutively formed on an end of the abutment wall  61 D near the insertion port  41 . 
     The abutment walls  61 D are formed as slant surfaces that incline toward the direction in which the abutment walls  61 D come closer to each other toward the releasing direction of the male member A. Specifically, the slant surfaces have substantially the same slant as those of the back outer side walls  31 D of the engaging portions  30  so as to abut to those of the back outer side walls  31 D of the engaging portions  30 . The engaged wall  61 E is a wall with which the back side wall  31 E of the engaging portion  30  is engaged, which is formed as a wall surface that substantially orthogonally crosses the inserting direction of the male member A. Further, the concave  61  formed on the top wall  40 A and the concave  61  formed on the bottom wall  40 B are respectively opened at the outer surface of the top wall  40 A and the outer surface of the bottom wall  40 B. 
     When the pair of the legs  20  of the male member A is inserted through the insertion port  41  of the female member B, as shown in  FIG. 7 , the engaging portions  30  provided on each of the distal ends of the legs  20  are inserted into the inside of the female member B while being guided by the guide groove  50  and the distal ends of the pair of the legs  20  are elastically deformed in the direction in which the distal ends come closer to each other. Then, once the engaging portions  30  reach the engaged portions  60  over the guide groove  50 A, as shown in  FIG. 8 , each of the engaging portions  30  is displaced to be away from each other by the elastic restoring force of the pair of the legs  20  to be abutted to the abutment wall  61 D while pressing the abutment wall  61 D at the remote side in the releasing direction. 
     Each of the abutment walls  61 D is formed as a slant surface that inclines in the direction in which each of the abutment walls  61 D comes closer to each other toward the releasing direction of the male member A (i.e., the abutment surfaces  61 D of the engaged portions  60  to which the engaging portions  30  abut are formed as slant surfaces), the engaging portions  30  can be securely contacted with the engaged portions  60 . Accordingly, since there is no clearance between the engaging portion  30  and the engaged portion  60 , shakiness caused by the clearance can be prevented. 
     At this time, each of the engaging portions  30  abuts to each of the abutment walls  61 D while being urged in the direction in which each of the engaging portions  30  get apart from each other by the elastic restoring force of each of the legs  20  and each of the abutment walls  61 D is formed as a slant surface that inclines in the direction in which each of the abutment walls  61 D comes closer to each other toward the releasing direction of the male member A. Accordingly, there is no clearance also in the inserting direction of the male member A and the direction orthogonal to the inserting direction of the male member A, in which the pair of the legs  20  elastically deform. Therefore, shakiness in these two directions can be prevented. 
     Further, since each of the engaging portions  30  abut each of the abutment walls  61 D while being urged in a direction to be apart from each other (i.e. each of the engaging portions  30  abuts the slant surface that inclines in the direction in which each of the engaging portions  30  comes closer to each other toward the releasing direction of the male member A), resistance can be applied in the releasing direction of the male member A to maintain the engaging force between the male member A and the female member B. 
     In the present embodiment, since the back outer side wall  31 D of the engaging portion  30  which abuts to each of the abutment walls  61 D is also formed as a slant surface that substantially corresponds to the slant surface of each abutment wall  61 D, the abutment wall  61 D of the engaged portion  60  and the back outer side wall  31 D of the engaging portion  30  can be brought into face-to-face contact to maintain the resistance in the releasing direction of the male member A. Thus, the engaging force between the male member A and the female member B can also be kept higher. 
     In addition, when a force in releasing direction affects the male member A and female member B while the male member A and the female member B are engaged with each other, the back outer side wall  31 D of the engaging portion  30  is moved along the slant surface of the abutment wall  61 D of the engaged portion  60  so that the back side wall  31 E of the engaging portion  30  is engaged with the engaged wall  61 E of the engaged portion  60 . At this time, the connecting cord  23  that bridges between the inner surfaces of both of the guide pieces  22  suppress the inward deformation of the leg  20  to keep the engagement between the back side wall  31 E of the engaging portion  30  and the engaged wall  61 E of the engaged portion  60 . 
     Since the back side wall  31 E of the engaging portion  30  and the engaged wall  61 E of the engaged wall  60  are formed as walls that substantially orthogonally cross the inserting direction of the male member A, the force in the releasing direction which affects the male member A and the female member B can be securely received by these back side wall  31 E and the engaged wall  61 E. Thus, the male member A and the female member B are not easily disengaged by the force in the releasing direction applied on the male member A and the female member B. 
     When the male member A is inserted into the female member B, the butting portion  14  of the male member A closely touches with the butting portion  42  of the female member B, which gives simple appearance to the holder. Since the male member A and the female member B can be engaged while being closely contacting with each other, shakiness therebetween can be further effectively prevented. 
     To release the male member A from the female member B, the outside surface of the guide piece  22  of the leg  20  projecting from the opening  45  of the female member B is pressed inward. The leg  20  of the male member A is accordingly elastically deformed inward to release the engaging portion  30  from the engaged portion  60 . When the male member A is disengaged from the female member B in this condition, the male member A can be released from the female member B. 
     The present invention is not limited to the buckle described in the above embodiment, but includes the following modifications. 
     In the above embodiment, the engaging portion  30  is constituted by the substantially pentagonal projection  31  and the engaged portion  60  is constituted by the substantially pentagonal concave  61 . However, they are not limited to the combination of the pentagonal projection and concave. 
     For example, the engaging portion  30  may be any polygon having the back outer side wall  31 D (abutment portion) and the back side wall  31 E (engaging wall) on adjoining sides thereof. The engaged portion  60  may be any polygon having the abutment wall  61 D and the engaged wall  61 E on adjoining sides thereof. 
     In the above embodiment, the back outer side wall  31 D (abutment portion of the engaging portion  30 ) is formed as a slant surface that makes a substantially 45 degree angle with respect to the inner side wall  31 A. However, the angle is not limited thereto. For example, the angle may be selected within the range of about 30 to about 60 degrees. 
     Similarly, as for the abutment wall  61 D of the engaged portion  60 , the angle may be selected within the range of about 30 to about 60 degrees. 
     Accordingly, as shown in  FIG. 10 , both of the abutment wall  61 D of the engaged portion  60  and the back outer side wall  31 D (abutment portion of the engaging portion  30 ) may be formed as arcs that have substantially the same curvature. In other words, the same advantages can be expected by the circular surfaces, which curve in the direction in which the arcs come closer with each other toward the releasing direction of the male member A and show a convex profile seeing from the center of the concave  61  and the engaging portion  30 . 
     In the above embodiment, the guide groove  50 A is formed on the inside of the female member body  40  from the insertion port  41  toward the engaged portion  60  so that the guide groove  50 A guides the engaging portion  30  while elastically deforming the distal ends of the pair of the legs  20  in the direction in which the distal ends come closer to each other. However, the guide  50  that elastically deforms the distal ends of the pair of the legs  20  in the direction in which the distal ends come closer to each other is not limited thereto. 
     For example, as shown in  FIG. 11 , a projection  50 B that abuts on the engaging portion  30  and elastically deforms the distal ends of the pair of the legs  20  in the direction in which the distal ends come closer to each other and then elastically recovers the distal ends in the direction in which the distal ends get apart from each other may be provided on the inside of the female member body  40 . 
     In the above embodiment, the concave  61  formed on the top wall  40 A and the concave  61  formed on the bottom wall  40 B are respectively opened at the outer surface of the top wall  40 A and the outer surface of the bottom wall  40 B, but the arrangement is not limited thereto. For example, as shown in  FIG. 11 , both or one of the concaves  61  may be formed to have substantially the same depth as those of the projection  50 B and the bottom wall of the guide groove  50 A without opening at the outer surface of the top wall  40 A and the bottom wall  40 B. In this way, since no opening is formed on the outer surface of the top wall  40 A and the bottom wall  40 B, intrusion of foreign materials from the opening can be prevented and the design can be simplified. 
     In the above embodiment, V-shaped butting portions  14  and  42  are respectively formed on the male member A and the female member B. However, the shape is not limited to the V-shape but may be a flat surface. 
     In the above embodiment, cord attachment holes  11  and  43  (cord attachment portions) are respectively formed on the male member A and the female member B. However, the female member B may not be provided with the cord attachment hole  43 . In other words, the female member body  40  of the female member B may be directly fixed on other members. 
     Though the cord attachment hole  11 A of the male member A exhibits a substantially pentagonal shape that extends toward the projecting direction of the pair of legs  20  while gradually decreasing the width dimension (i.e. a dimension orthogonal to the projecting direction of the legs  20 ) thereof, the cord attachment hole  11 A may be formed in a substantially triangular shape. 
     Further, a connecting bar may be bridged across the width direction of the cord attachment hole  43  of the female member B to enable length adjustment of the cord. 
     The cord is not limited to a strip-shaped cord, but may be a thin string with small width. 
     In the above embodiment, the male member A and the female member B are molded by synthetic resin (injection molding or injection compression molding). However, the male member A and the female member B may be made of metal and the like. 
     Although preferable embodiments and various modifications have been exemplified above, these embodiments and the modifications may be employed in combination. 
     The priority application Number JP 2007-175411 upon which this patent application is based is hereby incorporated by reference.