Meson, air hole buckle and bookbinding die

The utility model discloses a meson, which comprises an annular cylinder, the overturning piece is arranged at the first end of the annular barrel in the circumferential direction of the annular barrel, the overturning piece extends towards the middle of the annular barrel and towards the second end of the annular barrel, and an outwards-concave overturning angle is formed in the overturning piece; the locking edge is arranged at the second end of the annular cylinder in the circumferential direction of the annular cylinder, and the locking edge extends towards the center of the annular cylinder. In the binding process, the turning angle of the turning piece forces the air hole to be turned along the inner wall of the turning piece, so that a rolling part is formed, the rolling part is hidden in a cavity defined by the turning piece, the annular barrel and the lock catch edge, the rolling part extrudes the lock catch edge, the meson is pressed on the fabric, and binding of the air holebuckle is completed. The