Buckle for chest strap of knapsack

1. A buckle for a chest strap of a knapsack, comprising: a plug member including a plug plane portion formed at a front side of a plug member base so as to be connected to the plug member base via a plug inner-side slope, a plug front-end slope extending forward from the plug plane portion, a first magnet embedded in a middle portion of the plug plane portion, and coupling protrusions aligned vertically and protruding from opposite sides of the first magnet; and

a socket member including a socket plane portion formed at a front side of a socket member base so as to be connected to the socket member base via a socket inner-side slope, a socket front-end slope extending forward from the socket plane portion, a second magnet embedded in a middle portion of the socket plane portion, and coupling recesses formed in opposite sides of the second magnet so as to correspond to the respective coupling protrusions,

wherein the plug member and the socket member are separably connected to each other,

wherein each of the coupling protrusions of the plug member includes a hook portion formed on an inner front end thereof and a curvilinearly curved portion formed on an outer surface thereof, and each of the coupling recesses of the socket member includes a raised portion formed on an outer circumference thereof so as to correspond to the hook portion of each of the coupling protrusions, and

wherein each of the coupling recesses of the socket member further includes an inclined guide portion formed on an inner circumference thereof so as to define an upwardly expanded opening so that the inclined guide portion comes into contact with the curvilinearly inclined portion to enable easy separation of each of the coupling protrusions of the plug member from each of the coupling recesses.

2. The buckle according to claim 1 , wherein each of an exterior angle between the plug plane portion and the plug inner-side slope, an interior angle between the plug plane portion and the plug front-end slope of the plug member, an exterior angle between the socket plane portion and the socket inner-side slope, and an interior angle between the socket plane portion and the socket front-end slope of the socket member is an obtuse angle having a same degree.

3. The buckle according to claim 1 , wherein, when the plug member and the socket member are coupled to each other so that the plug plane portion and the socket plane portion are attached to face each other by the first and second magnets, the plug front-end slope and the socket inner-side slope are located close to each other so as to face each other, and the socket front-end slope and the plug inner-side slope are located close to each other so as to face each other.

4. The buckle according to claim 1 , wherein the inclined guide portion has a smaller inclination angle than an inclination angle of the curvilinearly inclined portion.

5. The buckle according to claim 1 , wherein each of the plug member or the socket member includes either a crossbar or a strap-hooking bar, which are selectively formed at a rear side of the respective plug member base or socket member base.

6. The buckle according to claim 1 , wherein the plug member or the socket member includes an elevating rail holder provided on a rear end thereof so as to be vertically movably coupled to a rail, which is installed on a shoulder strap of the knapsack.

7. The buckle according to claim 1 , wherein the plug member includes a seating recess formed in an outer surface thereof so that an external magnet, which corresponds to the first magnet embedded in the plug member, is seated.

8. The buckle according to claim 7 , wherein the seating recess and the embedded first magnet are connected to each other via an aperture.

9. The buckle according to claim 7 , wherein the seating recess is provided on a circumference thereof with a protruding support portion to support the external magnet seated in the seating recess.

10. A buckle for a chest strap of a knapsack, comprising:

a plug member including a plug plane portion formed at a front side of a plug member base so as to be connected to the plug member base via a plug inner-side slope, a plug front-end slope extending forward from the plug plane portion, a first magnet embedded in a middle portion of the plug plane portion, coupling protrusions vertically aligned and protruding from opposite sides of the first magnet, and a seating recess formed in an outer surface of the plug plane portion; and a socket member including an elevating rail holder having a circular cross-sectional rail groove formed at a rear side of a socket member base, a socket plane portion formed at a front side of the socket member base so as to be connected to the socket member base via a socket inner-side slope, a socket front-end slope extending forward from the socket plane portion, a second magnet embedded in a middle portion of the socket plane portion, and coupling recesses formed in opposite sides of the second magnet so as to correspond to the respective coupling protrusions,

wherein the plug member and the socket member are separably connected to each other wherein each of the coupling protrusions of the plug member includes a hook portion formed on an inner front end thereof and a curvilinearly curved portion formed on an outer surface thereof, and each of the coupling recesses of the socket member includes a raised portion formed on an outer circumference thereof so as to correspond to the hook portion of each of the coupling protrusions, and

wherein each of the coupling recesses of the socket member further includes an inclined guide portion formed on an inner circumference thereof so as to define an upwardly expanded opening so that the inclined guide portion comes into contact with the curvilinearly inclined portion to enable easy separation of each of the coupling protrusions of the plug member from each of the coupling recesses.