A mechanical lock comprising:
- a lock cylinder including a front lock cylinder, a back lock cylinder, a self-locking control mechanism, and a moving section control mechanism;
- said front lock cylinder including a front external cylinder, a front middle cylinder and a front internal cylinder;
- two pin sets arranged longitudinally in the front cylinder;
- a positioning groove of the internal cylinder is in communication with a key hole, so that after rotation of the internal cylinder the positioning pin of the internal cylinder is fitted with an anti-drawout groove of a key, whereby the key is not permitted to be drawn out from the key hole;
- said back lock cylinder including a back external cylinder and a back internal cylinder having a pin-set-like arrangement;
- said back internal cylinder being fastened rigidly together with the front middle cylinder of the front lock cylinder and said front external cylinder being fastened rigidly together with the back external cylinder;
- a driving rod being connected rigidly with said back internal cylinder;
- said self-locking control mechanism including a self-locking control plate, connecting rods and a self-locking control rod;
- said self-locking control plate being located between the front and back lock cylinders and can drive the connecting rods and the self-locking control rod to move toward the front lock cylinder;
- the self-locking control rod extending out from the lock cylinder;
- said moving section control mechanism including a V-shape element used to drive a moving section control rod to rotate a ball and bar mechanism which is raised up with rotation of the lock cylinder and then moves the bar to rotate the V-shape element, and the moving section control rod extending out from the lock cylinder;
- a lock body portion including a body and a bottom plate;
- said bottom plate being secured on a door;
- an external moving section, an external moving head and a self-locking control pin arranged in series on a side of the bottom plate facing the body;
- said moving section control rod being fitted with said external moving section;
- said external moving section being used to control movement of the external moving head and can be rotated to release said external moving head by said moving section control rod;
- said self-locking control pin being pushed by said self-locking control rod extending into said body portion;
- said driving rod from the lock cylinder being fitted with said external moving head used for controlling movement of a lock tongue;
- said lock body portion includes the lock tongue;
- an internal moving head whose movement can be controlled from an interior of a room being provided to control a position of the lock tongue;
- a self-locking element with a spring alarm sheet being located below the lock tongue and hinged to the lock body portion;
- one end of the self-locking element being controlled by the self-locking control pin, and the other end of the self-locking element being engageable with the lock tongue when the lock tongue is inserted in a lock tongue chamber;
- an internal lock mechanism being provided and controlled by secret code disks;
- said lock tongue chamber being provided to fit with the lock tongue.