What is the working principle of padlocks?

Generally padlocks have lock cores. In addition to the hole for inserting the key, there are several round holes in the lock core. These round holes correspond to those on the lock body, and a spring and two copper marbles with different heights can be put in them. After the key is inserted, the two marbles are pushed to different heights due to different tooth positions. If the boundary of two marbles in all holes is equal to the circumference of the lock core, the lock core can rotate in the lock body, and the lock is opened. This is how ordinary padlocks work.