Watch strap buckle with hidden locking device

A watch strap buckle with a locking device, comprising a U-shaped snap ring composed of a left support, a right support and a cross rod, wherein a rotating shaft is arranged at an open end of the U-shaped snap ring;

• one end of a buckle tongue is mounted on the rotating shaft;
• the other end of the buckle tongue is inserted into a watch strap hole, thus fastening a watch strap;
• the locking device comprises a locking box linked to the buckle tongue and arranged at the one end of the buckle tongue close to the rotating shaft;
• the locking box comprises a box body and an upper cover;
• at least one connecting rod capable of extending and retracting left and right, and a spring bolt linked to the at least one connecting rod is mounted in the box body;
• at least one first limiting hole for the spring bolt to extend and retract is arranged on a left side surface or a right side surface of the box body;
• and at least one second limiting hole that corresponds to the first limiting hole and allows the spring bolt to extend and retract is also arranged at a corresponding position of the left support or the right support of the U-shaped snap ring;
• wherein an abdication hole is formed in the upper cover of the locking box;
• the abdication hole is used for allowing a retraction actuation rod to pass to drive the at least one connecting rod and to retract the spring bolt from the at least one second limiting hole on a side surface of the left support or the right support of the U-shaped snap ring, thereby releasing the buckle tongue.