When installing this kind of lock, the lock is fixed on the tripod with gongs and splints. This kind of lock is formed by pressing iron sheet. The structure mainly includes a lock body, a lock core, a spring, a pin and a lock column, a tension spring, a bayonet piece, and a bolt. Its body is locked in a metal shell. The lock core has five marble holes and 10 marbles, which belong to a small five-tooth lock, and there is a card at the end of the lock core. This dial card can toggle the bayonet to move the bayonet up and down. When the bayonet pin is stuck in a groove of the long lock cylinder, the inpatient lock cylinder can be controlled to lock the wheel and prevent the wheel from rotating. The tail end of the lock cylinder is equipped with a force spring. There is also a button at the center of the outside of the lock column. This pin is exposed to the outside of the lock body (the entire lock body shell is wrapped in iron). In this locked state, the bayonet pin jams the groove on the lock lever, so that the lock cylinder cannot move. If it is inserted into the key, turn the lock center 90 degrees clockwise, drive the card, and pull the pin up, so that nothing gets stuck in the groove on the lock cylinder, and the lock cylinder is under the action of the tension spring. Pull back into the lock body, and the lock is opened. At this time, the key hole of the lock core is 90 degrees from the original locked state. This is because a spring installed in the lock body is stuck against the lock core, so that the lock cannot automatically spring back to the original position. In this way, the concave tooth groove on the key is stuck by the pin and cannot be directly pulled out of the key hole of the lock core. Unless the lock is re-locked and the lock core and key are returned to their original positions, the key can be removed.