There were many outstanding mechanical inventors in ancient China. Which ones and which ones applied the cam principle in Jin Dynasty?

The account and legend about China's mechanical tradition has been circulated for a long time, which has aroused the attention and curiosity of skilled technicians and literati in past dynasties. During the Three Kingdoms period, Ma Jun once again invented the predecessor's guide car and rollover. At the end of the Ming Dynasty, Wang Zheng tried to restore the guide car and the wooden cow. He wrote Atlas of Agricultural Books and Farm Tools, Xue wrote Zi Ren's Legacy System, and Song wrote Tiangong, which recorded their understanding of machinery. The artist's works also retain the technical information of ancient machinery. For example, the "Car Map at the Gate" of the Five Dynasties carefully drew the water mill map, and the "Riverside Map at Qingming Festival" described the technology of boats, cars and bridges in the capital of the Song Dynasty (now Kaifeng).

China ancient machinery attracted the attention of foreign scholars earlier. From 1909, Giles, Moore, Lanchester and others first speculated on the transmission mechanism of the south guide car [1](P52). Since the 1920s, historians, mechanical engineers and cultural experts in China have started literature research and special research on ancient machinery in China. 1925, Zhang Yinlin translated an English paper entitled "Study on the Structure of Car Guide in Song Dynasty and Wu Deren" and wrote "Drum Car Structure in the Records of Song Ludaolong and Wu Deren", which was published in the Journal of Tsinghua. From 65438 to 0935, Liu Xianzhou published "Historical Materials of Mechanical Engineering in China" in Tsinghua University, which preliminarily sorted out the descriptions of machinery in China's ancient books. Wang Zhenduo tried to restore ancient mechanical devices according to the records of ancient documents. 1936 published "speculation on the making method of seismograph of Han Hou Feng" in Yanjing Journal, and restored the south guide car and drum car [2] in Beiping Research Institute (P63). These early works initiated the research on the history of mechanical engineering in China.