A lock is a device used by people in daily life to lock doors, prevent theft and protect property. It is commonly known as the "doorkeeper". Our country has used locks to serve our lives for more than 5,000 years. Over the long years, with the continuous development of human civilization, the uses of locks have continued to expand, and their scope of use has become wider and wider. From ancient times to the present, my country's lock-making industry has been very developed, producing many inventions and making positive contributions to human civilization. 1. The origin of locks - wooden locks. The earliest locks in the world originated from Chinese wooden locks, or wooden structure locks. Early wooden locks have been discovered in the Yangshao Cultural Site dating back 5,000 years. There are written records about wooden warehouse locks and keys in the Zhou Dynasty. Early wooden locks had a simple structure and bulky shape. They mostly used bamboo poles as keys, which were easy to open. During the Spring and Autumn Period and the Warring States Period, after improvements by Gongshu Ban (i.e. Lu Ban), confidentiality was enhanced and copper keys began to be made. Among the people, wooden locks were used until the Ming and Qing Dynasties. 2. A leap in locks - three-spring locks. Because wooden locks were not strong enough, they were later made of bronze, but the structure was simple. Copper reed structural locks appeared in the Han Dynasty, commonly known as three-reed locks or reed locks, which used the elastic force of two or three plate-shaped copper plates to achieve closing and opening functions. Because the reed device can be changed in many ways, and the key hole shape can be used to determine the style of the key, the safety performance and confidentiality are a big step forward compared with wooden locks, and the scope of use is also wider, so it is called a wide lock. This type of lock has been continuously improved and developed since the Tang Dynasty and was used until the 1950s. More than 120 different styles appeared, some of which used special technologies such as secret doors, directional, two-open, keyless, and text passwords to make locks more popular. The level of confidentiality has been greatly increased. At the end of the second century BC, the reed locks produced in my country were introduced to ancient Rome along the "Silk Road". To this day, the Graz City Museum in Austria still collects reed locks from the Han Dynasty in my country. 3. Modern locks - blade locks. In the 8th century AD, the Eastern Romans made the original blade locks, also known as keyhole locks. They used the key teeth to move the blade gaps that fit within the lock to open and close. In the 18th century AD, the Englishman Danik Porter invented the cam rotor lock. The metal blades in the lock were controlled by springs to rotate. When the key is inserted into the lock, the blade must first be rotated to contact the gap in the lock tongue before it is opened. In the 19th century, European manufacturers invented advanced cam rotor locks, and the number of key patterns increased to 1,600. Various subsequent improvements increased the number of key patterns to tens of thousands of variations. The key of the blade lock is beautiful and elegant in shape and is recognized as the symbol of locks and keys. Many countries make it into large golden keys and give them to friendly countries and distinguished guests as a symbol of respect, peace and friendship. my country began to produce blade locks in the Qing Dynasty, and they were gradually replaced by pinball locks after the 1930s. After the founding of New China, many companies still produced iron padlocks with blade structures.