1 year, Zhang Heng first invented ancient clocks and watches: before 1300, human beings mainly used astronomical phenomena and mobile substances to keep moving on time. For example, the sundial is timed according to the orientation of the sun's shadow; When clepsydra and hourglass are flow meters that use water and sand. In the Eastern Han Dynasty, Zhang Heng made a leak-turning armillary sphere, and connected the elephant with a timed leak kettle by a gear system. The leaky kettle drips water to push the elephant to rotate evenly, once a day. This is the earliest mechanical clock. Su Ge and Han Honglian, etc. In the third year of the Northern Song Dynasty (1088), the water transport instrument platform was created and the escapement mechanism was used.

2 1350, the Italian Danti made the first mechanical clock with simple structure, with a daily difference of 15 ~ 30 minutes, and the indicating mechanism was only the hour hand;

In 3, 1500 ~ 15 10, Henleith of Germany first replaced the heavy hammer with a steel spring and created a small mechanical clock with a crown wheel escapement mechanism. 1582 or so, Galileo of Italy invented the gravity pendulum;

In 4, 1657, Huygens of the Netherlands introduced the gravity pendulum into the mechanical clock and founded the pendulum clock.

In 5, 1660, Hook of England invented the hairspring, and replaced the crown wheel escapement with the backward escapement.

6, 1673, Huygens applied the speed regulator composed of hairspring to portable clocks and watches;

In July, 1675, Clemente of England made the simplest anchor escapement with fork-hoof device, which has been used for single pendulum wall clocks.

8, 1695, Tom Ping of England invented the I-wheel escapement mechanism;

In 9, 17 15, Graham of England invented the static escapement, which made up for the deficiency of the backward escapement and laid the foundation for the development of precision mechanical clocks.

10, 1765, March of England invented the free anchor escapement, which is the predecessor of modern fork-hoof escapement;

1 1, 1728 ~ 1759, Harrison of England made a high-precision standard navigation clock;

12 years, 1775 ~ 1780 years, Arnold of England created the escapement mechanism of precision watches.

From 13, 18 to 19 century, the watch manufacturing industry gradually realized industrial production and reached a fairly high level.

14, in the 20th century, with the rapid development of electronic industry, battery-driven clocks, AC clocks, electromechanical watches, analog electronic clocks and digital electronic clocks came out one after another, and the daily difference of clocks was less than 0.5 seconds. With the combination of microelectronics technology and precision machinery, clocks and watches have entered a new era of timeliness.