The bicycle chain lock body is made of aluminum alloy, which is cylindrical, with a diameter of about 25 mm and a length of about 5 cm. The lock core is made of copper and installed in the central part of the lock body. This lock is connected to an iron chain with a thickness of about 6 mm at one end of the plane of the lock body. The whole iron chain is wrapped by plastic hose, and the length of the chain is about one foot eight inches. The other end of the chain is connected with a steel lock stud head. There is a circular groove around the lock cylinder head. There is a round hole on the plane at the other end of the lock body, that is, the lock column hole, which just fits the lock column head. There is a lock pin connected with the lock core in the round hole.

When the lock needs to be closed, push the wrench on the lock ring by hand, and the lock ring will overcome the pull of the large tension spring and extend along the track of the lock shell to the outside of the lock body to enter the other mouth. At this time, the lock is at the tail slot of the lock ring. The lock moves downward along the guide slot under the action of the small tension spring and enters the tail slot of the lock beam. The lock ring is locked by the lock. When the lock moves downward, the lock also drives the eccentric shaft of the lock core to rotate, making the lock core turn back to its original position, and the key can be removed.