The automatic mechanical watch is based on the structure of the ordinary mechanical watch, and adds a part of the automatic mechanism device, which is automatically wound by the movement of the arm of the wearer in daily life. The word "Automatic" is printed on the dial, indicating that it is an automatic mechanical watch, which is also divided into a fully automatic mechanical watch and a semi-automatic mechanical watch.

To understand the principle of an automatic mechanical watch, you need to understand its automatic mechanism. The automatic mechanism is oscillated by a heavy hammer (automatic oscillating weight), and the special function of automatic winding is realized by connecting the automatic winding gear train and the prime mover.

Around 1920 in England, watchmaker John Howard invented and manufactured the prototype of the modern automatic mechanical watch, which laid the foundation for the development of the automatic mechanical watch industry. But he was not the first to make automatic mechanical watches. As early as 1770, there was a Swiss, Louis Borrell, who made the earliest automatic watch. Due to hand-made, the quantity is very small, and it is difficult to find in the flea market. Because it is the predecessor and birthplace of modern automatic mechanical watches. As a result, the Swiss watchmaking industry has also become famous.

The difference between semi-automatic and full-automatic automatic watches: the driving part of the automatic mechanical watch is the self-weight hammer (ie the automatic oscillating weight), which is automatically wound through a set of automatic gear trains, and is automatically wound by arm swing. Due to the different working states of the heavy hammer and the automatic winding system used in automatic watches, the structure of automatic mechanical watches can be divided into the following four types:

1. Swing type unidirectional upper strip;

2. Swing type two-way winding;

3. Rotary unidirectional upward movement,

4. Rotary two-way winding;

The swinging automatic weight can only swing about 120° in the watch machine, which is semi-automatic. The rotary automatic weight can rotate 360° in the watch machine, which is called fully automatic. This is the principle of semi-automatic and fully automatic mechanical watches.

In the early automatic mechanical watches, the automatic heavy hammer was also produced in a straight line reciprocating motion in the two grooves on the center of the watch. This automatic mechanism is called automatic drawer; because of its poor winding effect, it was eliminated early. But because of its limited production, it is very collectible.

Some automatic mechanical watches have a pointer on the dial, which shows the stock of automatic winding, and can judge the reliability of automatic winding. Due to the complexity of the mechanism, it needs to be composed of 14 parts, so there are not many automatic watches using this type of mechanism.