Abstract:
Provided is a buckle including a plug member and a socket member, wherein the plug member includes lock arms and a guide rod located at a middle position between the lock arms, and the socket member includes a holder formed in a chamber so as to catch the lock arm. The guide rod is provided on the front end thereof with a holding member, and the socket member is centrally provided with a guide groove for the coupling of the guide rod and is also provided with a holding protrusion for the coupling of the holding member. As such, in addition to the coupling between the lock arm and the holder, another coupling structure is provided so as to prevent the buckle from being easily unfastened by unintentional external contact or pressure while ensuring convenient separation of the buckle with one hand as needed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority to Korean patent application No. 10-2015-0154883 filed on Nov. 5, 2015, the disclosure of which is incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The present invention relates to a buckle, and more particularly, to a buckle, which includes a socket member and a plug member separably coupled to each other, each of the socket member and the plug member being mounted on an end of a belt or strap attached to any of various articles, such as, for example, an article of clothing, a bag, a knapsack, or a helmet. 
         [0004]    Description of the Related Art 
         [0005]    Generally, a buckle is a fastening device in which a plug member and a socket member are coupled and fixed to each other as described above. These constituent members of the buckle are integrally molded from a plastic material so as to implement elastic coupling therebetween. 
         [0006]      FIG. 1  is a schematic perspective view illustrating an example of a conventional buckle. The conventional buckle includes a plug member  10  and a socket member  20 . 
         [0007]    As illustrated in  FIG. 1 , the plug member  10  includes a pair of lock arms  12 , which protrude in a straight line from a base  11  of a body and have elasticity. A fastening portion protrudes outward from the front end of each lock arm  12 . The plug member  10  further includes a guide rod  13 , which is located between the lock arms  12  and extends a long length in a straight line from the base  11 . The socket member  20  defines a chamber  21 , which is open from the front end of the socket member  20  so as to accommodate the plug member  10  therein. The socket member  20  is provided in opposite sidewalls thereof with a pair of holes  22  so that the respective lock arms  12  are elastically coupled in the holes  22 . 
         [0008]    When the plug member  10  is inserted from the open front end of the socket member  20  through the chamber  21 , the lock arms  12  formed on opposite sides of the plug member  10  are elastically bent inward as the outer side surfaces thereof slide along the inner sidewalls of the socket member  20 . Then, the lock arms  12  are elastically returned outward when the ends thereof are located in the respective holes  22 , thereby being seated in and fastened into the holes  22 . 
         [0009]    When attempting to unfasten the buckle, pressure may be applied from opposite outer sides to the lock arms  12  of the plug member  10 , which are exposed from the holes  22  in the socket member  20 , so that the respective lock arms  12  are separated from the holes  22  in the socket member  20 . When the plug member  10  is pulled outward simultaneously with the separation of the lock arms  12 , the plug member  10  and the socket member  20  are separated from each other. 
         [0010]    In the conventional buckle, however, as described above, the connection of the plug member and the socket member requires a user to grip the plug member and the socket member with both hands so as to insert one into the other. In the same manner, the separation of the plug member and the socket member requires the user to grip the plug member and the socket member with both hands so as to push and separate the lock arms of the plug member. 
         [0011]    Because the user needs to use both hands to fasten the buckle, the user cannot perform any other motion with the hands even if the user needs to manipulate, for example, a belt or strap installed on, for example, a knapsack that the user wears when performing an activity, such as climbing, trekking or the like. Also, the user needs to put down any article being held in the hands in order to fasten the buckle. Due to this troublesome manipulation, there is a demand for a buckle that enables more simplified fastening manipulation with one hand. 
         [0012]    Although the user may try to unfasten the conventional buckle by simply pushing the lock arms of the plug member with one hand, in this case, the elastic lock arms may propel the plug member and the socket member away from each other in the course of being separated, thus causing a collision with any surrounding object. 
       SUMMARY OF THE INVENTION 
       [0013]    Therefore, the present invention has been made in view of the above problems of the related art, and it is one object of the present invention to provide a buckle in which the coupling and separation of a plug member and a socket member may be implemented in a simplified manner using one hand. 
         [0014]    It is another object of the present invention to provide a buckle in which the connection of a plug member and a socket member may be easily implemented by magnets attached to the respective members even when the members are simply brought close to each other. 
         [0015]    It is another object of the present invention to provide a buckle in which a plug member and a socket member may remain weakly attached to each other, rather than being completely separated from each other, by magnets attached to the respective members even after the coupling between the plug member and the socket member is released. 
         [0016]    It is a further object of the present invention to provide a buckle, to which various functional elements, such as an elevating buckle, a loop of a water supply hose, a whistle, a strap-fixing piece, and a ring, may be additionally coupled. 
         [0017]    In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a buckle including a plug member and a socket member separably connected to each other, the plug member including a base, a pair of lock arms protruding from the base so as to be elastically coupled to the socket member, and a guide rod protruding from the base at a middle position between the lock arms, and the socket member including an upper plate, a lower plate, and a sidewall connecting the upper plate and the lower plate to each other so as to define a chamber, a front end of which is open so that the lock arms are accommodated in the chamber, and the socket member further including a holder provided in the chamber so that each lock arm is fastened to the holder, wherein the plug member is provided on a front end of each lock arm with an upwardly or downwardly protruding holding protrusion so that a push portion, which is pushed when attempting to separate the holding protrusion from the socket member, is located at a rear side of the holding protrusion, and wherein the socket member is provided in a middle portion thereof with an elongated guide groove for guiding the guide rod so that the chamber is divided into opposite chambers by the guide groove, each of the divided chambers being provided with upper and lower expanded holding portions for catching the holding protrusion when the plug member is completely coupled, and also being provided at an entrance side thereof with upper and lower entry slopes for guiding the holding protrusion so as to allow each lock arm to be inwardly constricted and introduced into the chamber, each entry slope being connected to the expanded holding portion. 
         [0018]    According to a feature of the present invention, the chambers in the socket member may be formed so as to extend a shorter length than the guide groove from opposite sides of a rear end of the guide groove, and the holding protrusion and the expanded holding portion may have curved contact surfaces so as to come into close contact with each other. 
         [0019]    According to an exemplary feature of the present invention, each lock arm may have an outer side surface, a middle portion of which protrudes outward, and the push portion may be formed so as to be inclined inward on a rear portion of the outer side surface. 
         [0020]    According to another feature of the present invention, the guide groove may have rail grooves formed in respective opposite inner side surfaces thereof, and the guide rod may have guide ribs protruding from opposite side surfaces thereof so as to correspond to the rail grooves. 
         [0021]    According to another feature of the present invention, the guide groove may be provided on an upper end or a lower end of each of opposite outer side surfaces thereof with a protruding guide portion for guiding the holding protrusion of the lock arm. 
         [0022]    According to another feature of the present invention, one end of the guide rod of the plug member and one end of the guide groove in the socket member may be provided respectively with magnets so that the guide rod is strongly guided into and attached to the guide groove by the magnetic force of the magnets when the plug member and the socket member are brought close to each other. 
         [0023]    Here, the holding protrusion of each lock arm may not be coupled to the expanded holding portion of the socket member in a state in which the magnet of the plug member and the magnet of the socket member are magnetically attached so as to coincide with each other, and the holding protrusion of the lock arm may be completely coupled to the expanded holding portion of the socket member when the plug member is further pushed in the attached state of both the magnets. 
         [0024]    According to another feature of the present invention, each of the plug member and the socket member may include a crossbar and a strap-hooking bar, which are selectively provided at a rear side of the base. 
         [0025]    According to another feature of the present invention, the plug member or the socket member may include an elevating rail holder provided on a rear end thereof. 
         [0026]    According to another feature of the present invention, the plug member or the socket member may include a loop provided on a rear end thereof so as to hold and fix a hose connected to a water bottle. 
         [0027]    According to another feature of the present invention, the plug member or the socket member may have a rear end configured to enable connection of a whistle. 
         [0028]    According to another feature of the present invention, the plug member or the socket member may include a strap connector provided on a rear end thereof. 
         [0029]    According to a further feature of the present invention, the plug member or the socket member may include a ring provided on a rear end thereof to enable connection of any of various loops. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0031]      FIG. 1  is a perspective view illustrating an example of a conventional buckle; 
           [0032]      FIG. 2  is a view illustrating an embodiment in which the present invention is applied to a knapsack; 
           [0033]      FIG. 3  is an exploded perspective view illustrating an example of a buckle according to the present invention; 
           [0034]      FIG. 4  is a perspective view illustrating the coupled state of  FIG. 3 ; 
           [0035]      FIG. 5  is a bottom exploded perspective view of the buckle according to the present invention; 
           [0036]      FIG. 6  is a sectional view taken along line A-A of  FIG. 5 ; 
           [0037]      FIG. 7  is a plan sectional view of a socket member according to the present invention; 
           [0038]      FIG. 8  is a view illustrating the coupling sequence of a plug member and the socket member according to the present invention; 
           [0039]      FIG. 9  is a sectional view taken along line B-B of  FIG. 8 ; and 
           [0040]      FIGS. 10 to 13  are exploded perspective views illustrating other embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    Hereinafter, a concrete embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
         [0042]      FIG. 2  is a view illustrating an embodiment in which the present invention is applied to a knapsack,  FIG. 3  is an exploded perspective view illustrating an example of a buckle according to the present invention,  FIG. 4  is a perspective view illustrating the coupled state of  FIG. 3 ,  FIG. 5  is a bottom exploded perspective view of the buckle according to the present invention,  FIG. 6  is a sectional view taken along line A-A of  FIG. 5 , and  FIG. 7  is a plan sectional view of a socket member according to the present invention. 
         [0043]    Referring to  FIGS. 2 to 7 , the buckle according to the present invention broadly includes a plug member  100  and a socket member  200 , which are separably coupled to each other. Both members are generally molded using a synthetic resin, and are used by being connected to straps  51  and S 2  of, for example, a knapsack, as illustrated in  FIG. 2 , which is a view illustrating the buckle in use. 
         [0044]    The plug member  100  includes a base  101 , and a crossbar  102  and a strap-hooking bar  103 , which are located side by side at the rear side of the base  101  and extend in the transverse direction of the plug member  100  so that a free end of the strap Si is fitted therebetween and is wounded thereon. The strap S 1  is alternately wound around the crossbar  102  and the strap-hooking bar  103  in order to enable adjustment in the length of the strap S 1 . Alternatively, only the crossbar  102  may be provided, in which case the free end of the strap S 1  is wound around the crossbar  102  and is sewn to the crossbar  102 . 
         [0045]    A pair of lock arms  105  extends forward in the same direction from opposite sides of the base  101 . 
         [0046]    The lock arms  105  have a symmetrical form about the center of the plug member  100 . Each of the lock arms  105  has a small thickness and extends from the base  101  so as to be elastically bent relative to the base  101 . In this case, a middle portion or an end of the lock arm  105  may have an expanded form, or may have any other rigid structure, in order to realize a sufficient strength. 
         [0047]    Each of the lock arms  105  is provided on the front end thereof with an upwardly or downwardly protruding holding protrusion  106 . As such, a pair of upwardly and downwardly protruding holding protrusions  106  are coupled to the socket member  200 . 
         [0048]    A push portion  107  is provided on the outer surface of each lock arm  105 . When it is desired to release the coupling between the holding protrusion  106  and the socket member  200 , the user may apply inward pressure to push the push portion  107 . Unlike the conventional buckle described above, the push portion  107  may be located at the rear side of the holding protrusion  106 , and may have a greater width than a remaining portion of the lock arm  105  in order to secure sufficient contact area with a finger. 
         [0049]    In addition, a central portion of each lock arm  105  may protrude further outward than a remaining portion of the lock arm  105 , and the push portion  107  may be located at the rear side of the protruding central portion. Through this structure, sufficient push force may be applied when the user pushes the plug member  100  into the socket member  200  while gripping the push portions  107  on the opposite sides with one hand. 
         [0050]    The plug member  100  further includes a guide rod  110  extending forward from the base  101  at a middle position between the lock arms  105 , and guide ribs  111  protrude from opposite side surfaces of the guide rod  110 . 
         [0051]    The socket member  200  includes an upper plate  201  and a lower plate  202 , which are opposite each other, and a sidewall  203 , which connects outer ends of the upper and lower plates  201  and  202  to each other, thereby defining a chamber  205  in order to guide and accommodate the plug member  100  therein. The socket member  200  further includes a crossbar  204  provided at the rear side of the chamber  205  so as to extend in the transverse direction of the socket member  200  in order to fix a free end of the strap S 2 . In the same manner as the plug member  100 , the socket member  200  may further include a strap-hooking bar in order to enable adjustment in the length of the strap S 2 . 
         [0052]    A guide groove  210  is formed in the center of the socket member  200  so as to extend a long length in the direction in which the plug member  100  moves. The guide groove  210  is formed to divide the chamber  205  into two chambers on the opposite sides, and is open at the front and rear sides thereof and at the upper side thereof. 
         [0053]    The guide groove  210  may have sufficient width to allow the guide rod  110  to be smoothly guided in close contact with the guide groove  210 . The guide groove  210  may be wider at the entrance side thereof than at the rear portion thereof in order to guide the introduction of the guide rod  110 , and correspondingly, the front end of the guide rod  110  may be gradually reduced in width with increasing distance from the base  101 . 
         [0054]    The guide groove  210  is provided in opposite inner side surfaces thereof with elongated rail grooves  211 . Thereby, when the guide rod  110  is inserted, the guide ribs  111 , formed on the outer side surfaces of the guide rod  110 , are inserted into and guided by the rail grooves  211 , which may ensure accurate movement of the plug member  100  without fluctuation. 
         [0055]    The chambers  205  of the socket member  200 , which are divided by the guide groove  210 , are formed so as to extend a shorter length than the guide groove  210  from opposite sides of the rear end of the guide groove  210 , such that the outer side surfaces of the guide groove  210  are exposed over a considerably long length. The exposed outer side surfaces of the guide groove  210  are provided on the upper ends thereof with protruding guide portions  212 , which guide the holding protrusions  106  when the lock arms  105  are introduced into or discharged from the respective chambers  205 . Alternatively, the protruding guide portions  212  may be formed on the lower ends of the outer side surfaces of the guide groove  210 . 
         [0056]    Each of the chambers  205  is provided therein with upper and lower holders  207 , which are configured to catch the holding protrusion  106  of the lock arm  105  so as to realize coupling between the plug member  100  and the socket member  200 . A slot  206  is formed between the upper and lower holders  207  so as to open a portion of the side surface of the chamber  205 . Thereby, the front end of the lock arm  105  is fitted into the slot  206 . 
         [0057]    Each of the holders  207  includes an entry slope  208 , which is gradually narrowed inward from the entrance of the chamber  205 , and an outwardly expanded holding portion  209  formed at the end of the entry slope  208 . 
         [0058]    As such, the entry slope  208  and the outwardly expanded holding portion  209  are continuously connected to each other. Through this continuous structure, the holding protrusion  106  of the lock arm  105  is guided by the entry slope  208  so that the front end of the lock arm  105  is introduced into the chamber  205  while being compressed inward. Then, when the holding protrusion  106  reaches the end of the entry slope  208 , the holding protrusion  106  is outwardly returned by the elasticity of the lock arm  105 , thereby being caught by the outwardly expanded holding portion  209 . 
         [0059]    When both the lock arms  105  are caught by the outwardly expanded holding portions  209 , the plug member  100  and the socket member  200  remain coupled to each other. The coupling between the plug member  100  and the socket member  200  is released only when the lock arms  105  are pushed from opposite sides so as to separate the holding protrusions  106  from the outwardly expanded holding portions  209 . 
         [0060]    Because the holding protrusion  106  is substantially caught by the outwardly expanded holding portion  209 , contact portions of the holding protrusion  106  and the outwardly expanded holding portion  209  are processed so as to have curved surfaces, which may ensure close contact therebetween. Accordingly, the plug member  10  and the socket member  200  remain firmly fixed without movement in the coupled state thereof. 
         [0061]    When attempting to insert the plug member  100  into the socket member  200 , the guide rod  110  is first inserted into the guide groove  210  so that the guide ribs  111  are guided by the rail grooves  211 , thereby guiding the introduction of the plug member  100 . The respective lock arms  105  of the plug member  100  are introduced into the respective chambers  205 , which are divided by the guide groove  210 . After coupling is completed, the base  101  of the plug member  100  is located at the entrance of the guide groove  210 . At this time, the guide rod  110  is coupled to the guide groove  210  so as to fill the entire guide groove  210 . In this state, the holding protrusions  106  of the lock arms  105  are elastically coupled with the outwardly expanded holding portions  209  of the holders  207 . 
         [0062]    When the plug member  100  and the socket member  200  are coupled to each other, the guide rod  110  is inserted into the space in the guide groove  210  and the lock arms  105  are inserted into the respective chambers  205 . In particular, the side surface of the front end of the lock arm  105  is thinner than the push portion  107 . As the thinner portion is fitted into the slot  206  in the chamber  205 , the guide groove  210  of the socket member  200  and the space defined by the chamber  205  and the slot  206  are filled with the guide rod  110  and the lock arm  105  of the plug member  100 , thereby causing the plug member  100  and the socket member  200  to come into close contact with each other. 
         [0063]    Meanwhile, the plug member  100  and the socket member  200  according to the present invention may implement coupling using magnets simultaneously with the above-described coupling. That is, a first magnet  120  and a second magnet  220  are respectively installed on one end of the guide rod  110  of the plug member  100  and one end of the guide groove  210  of the socket member  200  so as to be magnetically coupled to each other. 
         [0064]    Each of the first magnet  120  and the second magnet  220  may be mounted in the guide rod  110  or the guide groove  210 , or may be embedded in the lower surface thereof. Here, the first magnet  120  may be embedded in the front end or at a middle position of the guide rod  110 , and the second magnet  220  may be installed close to the front end of the guide groove  210 . 
         [0065]    Accordingly, in the state in which the first magnet  120  and the second magnet  220  are magnetically attached to each other, a portion of the guide rod  110  is introduced into the guide groove  210 , and the holding protrusion  106 , formed on the front end of each lock arm  105 , is located close to the entrance of the chamber  205 , rather than being introduced into the chamber  205 . That is, the plug member  100  and the socket member  200  are attached to each other, but are in a provisionally connected state, rather than being completely coupled to each other. 
         [0066]    In addition, the state described above is the state immediately before the guide rib  111 , formed on the side surface of the guide rod  110 , is fitted into the rail groove  211 . To this end, the guide rib  111  may be formed on the rear end of the side surface of the guide rod  110 . In the state in which the first magnet  120  and the second magnet  220  are attached to each other, the front end of the guide rib  111  is located close to the entrance of the guide groove  210 . 
         [0067]    When the plug member  100  is pushed into the socket member  200  in this state, the holding protrusion  106  is introduced into the chamber  205  and is caught by the outwardly expanded holding portion  209 , thereby causing the plug member  100  and the socket member  200  to be completely coupled to each other. 
         [0068]    The action of the buckle according to the present invention having the configuration described above will be described below. 
         [0069]      FIG. 8  is a view illustrating the coupling sequence of the buckle according to the present invention, and  FIG. 9  is a sectional view taken along line B-B of  FIG. 8 , illustrating the positions of the magnets in the state in which the plug member and the socket member are completely coupled to each other. 
         [0070]    First, when one member, among the plug member  100  and the socket member  200 , is brought close to the other member in order to couple the plug member  100  and the socket member  200  to each other, the plug member  100  and the socket member  200  attract each other by the magnetic force of the first magnet  120  and the second magnet  220 , thereby causing the first magnet  120  and the second magnet  220  to be momentarily attached to each other. Thereby, as illustrated in  FIG. 8(B) , the guide rod  110  of the plug member  100  is naturally seated in the guide groove  210  in the socket member  200 . 
         [0071]    In the state in which the first magnet  120  and the second magnet  220  are attached to each other, the lock arms  105  of the plug member  100  are not yet introduced into the chambers  205  in the socket member  200 , and the plug member  100  and the socket member  200  are in the provisionally connected state, in which the holding protrusions  106  formed on the front end of the lock arms  105  are close to the entrance of the chambers  205 . 
         [0072]    In this state, as illustrated in  FIG. 8(C) , when the plug member  100  is pushed into the socket member  200 , the guide rod  110  is introduced into the guide groove  210  so that the guide ribs  111  are introduced into the rail grooves  211 , and simultaneously, each lock arm  105  is introduced into the chamber  205  so that the holding protrusion  106  is guided by the entry slope  208  of the holder  207 . Thereby, the front end of the lock arm  105  is introduced while being pushed inward and compressed. 
         [0073]    When the lock arm  105  is continuously introduced until the holding protrusion  106  reaches the region at which the entry slope  208  ends, the front end of the lock arm  105  is elastically moved outward and returned by the elasticity of the lock arm  105 , thereby causing the holding protrusion  106  to be seated on and fixed by the outwardly expanded holding portion  209  as illustrated in  FIG. 8(D) . 
         [0074]      FIG. 9  is a sectional view illustrating the same state shown in  FIG. 8(D) . When the plug member  100  and the socket member  200  are completely coupled to each other, the first magnet  120  and the second magnet  220  slightly deviate from each other, and the coupling between the holding protrusion  106  and the outwardly expanded holding portion  209  controls the attractive force between the magnets  120  and  220 . 
         [0075]    In the course of introducing the plug member  100  into the socket member  200 , the guide rib  111 , formed on the side surface of the guide rod  110 , is connected to and guided by the rail groove  211  of the guide groove  210 , which may allow the plug member  100  to be stably moved in a straight line. 
         [0076]    The operation described above is realized with one hand. When one member, among the plug member  100  and the socket member  200 , is brought close to the other member, the first magnet  120  and the second magnet  220  strongly attract each other, causing the guide rod  110  to be naturally guided into the guide groove  210 . 
         [0077]    The chambers  205  of the socket member  200  are formed so as to extend a shorter length than the guide groove  210  from opposite sides of the rear end of the guide groove  210 , and thus most of the outside of the guide groove  210  is empty space. Therefore, when the guide rod  110  is guided along the guide groove  210  by magnetic force, the lock arms  105  at opposite sides of the guide groove  210  do not completely prevent the movement of the guide rod  110 . 
         [0078]    In addition, because the guide rib  111  is formed on the rear portion of the side surface of the guide rod  110 , the guide rib  111  does not completely prevent the magnetic force from bringing the guide rod  110  into close contact with the guide groove  210 . 
         [0079]    The holding protrusion  106  of the lock arm  105  seated as described above comes into close contact with the outwardly expanded holding portion  209  of the plug member  100 , thereby remaining fixed without moving. 
         [0080]    Then, when the plug member  100  and the socket member  200  are coupled to each other, the guide rod  110  and the guide groove  210  come into close contact with each other and the front end of the lock arm  105  comes into close contact with and is connected to the chamber  205  and the slot  206 . In this way, the plug member  100  and the socket member  200  are integrally and closely coupled to each other. 
         [0081]    When attempting to separate the plug member  100  from the socket member  200 , inward pressure is applied to the push portion  107  from the outside of the lock arm  105  so that the holding protrusion  106  of the lock arm  105  is separated from the outwardly expanded holding portion  209  of the socket member  200 , and simultaneously, the plug member  100  and the socket member  200  are momentarily moved away from each other by the magnetic force of the first magnet  120  and the second magnet  220 . Thereby, the first magnet  120  and the second magnet  220  are attached to each other, causing the plug member  100  and the socket member  200  to enter the provisionally connected state. 
         [0082]    In this state, the connection between the plug member  100  and the socket member  200  may be simply released by simply separating the magnets  120  and  220  from each other. 
         [0083]    Because the plug member  100  and the socket member  200  may be provisionally connected to each other by the magnets  120  and  220 , even while the coupling between the plug member  100  and the socket member  200  is being implemented with one hand, an operation of coupling and separating, for example, a belt or a strap may be performed with the other hand in some cases. The ability to perform different operations at the same time with respective hands is very advantageous. 
         [0084]    For example, in a situation, such as, for example, performing any of various tasks or climbing, one hand may often be used to grip or hold something. In this situation, it may be difficult to couple or release a buckle using two hands. 
         [0085]    According to the present invention, the buckle may be coupled or released with only one hand in the situation mentioned above, which may provide excellent convenience. 
         [0086]      FIGS. 10 to 13  illustrate other embodiments of the present invention.  FIG. 10  illustrates an embodiment in which, instead of the crossbar, an elevating rail holder  230  is provided on the rear end of the socket member  200 , which is coupled to the plug member  100 . As such, the buckle may be applied as an elevating buckle, which is installed to, for example, a shoulder strap of a knapsack. The elevating rail holder  230  may be installed on the rear end of the plug member  100 . 
         [0087]    Because the elevating buckle is installed to, for example, the shoulder strap of the knapsack so as to be vertically moved, even in this case, the plug member  100  and the socket member  200  may be respectively provided with the first magnet  120  and the second magnet  220 , thereby being simply connected to each other by magnetic force when they are simply brought close to each other. 
         [0088]      FIG. 11  illustrates an embodiment in which, in addition to  FIG. 10 , a loop  240  may be formed on one end of the elevating rail holder  230 , which is formed on the rear end of the socket member  200 . As such, a water supply hose, which is connected to a water bottle, may be connected and fixed to the elevating buckle, which is located on the chest region of the knapsack. In addition, a whistle  130  may be fitted to the crossbar on the rear end of the plug member  100  so as to be carried along with the buckle. 
         [0089]    When the user who wears a knapsack goes climbing or trekking, the user may carry a water bottle in the knapsack and may try to drink water through a hose of the water bottle without taking off the knapsack. In this case, the hose may be held and fixed on the loop  240 , which ensures the convenient use of the hose. 
         [0090]    In addition, when the whistle  130  is carried by being connected to the rear end of the plug member  100  according to the present invention, the whistle  130  may be simply used in an emergency situation. 
         [0091]    When the loop  240  or the whistle  130  is applied to the plug member  100  and the socket member  200 , which may be easily coupled to or separated from each other by the magnets  120  and  220 , various additional functions may be applied to the buckle. 
         [0092]      FIG. 12  illustrates an embodiment in which a strap connector  250  is provided on the rear end of the socket member  200 , which is coupled to the plug member  100 , so that the socket member  200  may be installed so as to be movable along a strap. 
         [0093]    A strap installed on, for example, a knapsack or a bag may be fitted into the strap connector  250  so that the buckle is movable on the strap so as to be adjustable in position. In the state in which the buckle is mounted on the strap, the plug member  100  and the socket member  200  may be conveniently coupled or separated to or from each other using the magnets  120  and  220 . 
         [0094]      FIG. 13  illustrates an embodiment in which, instead of the crossbar, a ring  260  may be provided on the rear end of the socket member  200 , which is coupled to the plug member  100 . Any of various small articles may be carried by being held on the ring  260 , or a loop, which is installed on, for example, a suspender or a strap, may be connected to the ring  260 . 
         [0095]    That is, when the ring  260  is provided on the socket member  200  and the plug member  100 , which are provided with the magnets  120  and  220 , any of various loops or small articles may be held on the ring  260 . Thereby, the ring  260  may provide the buckle with various functionalities. 
         [0096]    As is apparent from the above description, in a buckle of the present invention, magnets are provided in a guide rod of a plug member and a guide groove of a socket member so as to correspond to each other. Thereby, the plug member and the socket member may be primarily coupled to each other via magnetic attraction when they are simply brought close to each other. When the plug member is merely pushed with one hand in this state, the coupling between the plug member and the socket member may be accomplished, which enables more convenient use of the buckle. 
         [0097]    In addition, even in the state in which a lock arm is released from the socket member in order to unfasten the buckle, the plug member and the socket member remain weakly attached to each other by the magnets, which prevents, for example, a strap assembled with the buckle, from drooping or shaking. 
         [0098]    In addition, various functional elements, such as an elevating buckle, a loop for a water supply hose, a whistle, a strap-fixing piece, and a ring, may be additionally coupled to the buckle according to the present invention, which enables utilization of the buckle across various fields.