Top-and-bottom latch structure for lock

A top-and-bottom latch structure for a lock, comprising a lock formed by a casing mounted to a door panel, and a primary lock tongue, a lock core, and a handle spindle that is operatively coupled to the primary lock tongue via the lock core disposed in the casing, and tact switches disposed on upper and lower edges of the door panel, each of tack switches comprising a secondary lock tongue and a catching plate that has a portion engageable with a door frame associated with the door panel, wherein:

• the handle spindle is provided with a first and a second protruding rod disposed at different angles, and is provided with a first braking piece above the handle spindle and a second braking piece below the handle spindle, so that the first and second braking pieces are respectively coupled to the first and second protruding rods and thus the handle spindle, and the first and second braking pieces are respectively connected to fixing members above and below the casing by first connecting rods;
• the fixing members are connected to the tact switches of the door panel respectively by second connecting rods;
• when the door is closed, the tact switches are moved with the door panel toward the door frame, whereby the secondary lock tongues of the tact switches are embedded into the door frame and the catching plates are brought into engagement with the door frame to drive, via the second connecting rods, the fixing members toward the lock to rotate the handle spindle in a first rotation direction for extending, via the lock core, the primary lock tongue out to effect locking;
• and when the handle spindle is rotated in a second, opposite rotation direction, the primary lock tongue is drawn back, and the fixing members are driven, via the coupling between the first and second protruding rods and first and second braking pieces, to move toward the tact switches so as to make the second lock tongues of the tact switches disengage from the door frame to unlock.