The speedometer bezel is also a very common existence. Its main purpose is to measure the speed at which objects travel within a fixed distance, but it can also be used to achieve functions such as ranging.
The watch speedometer bezel is slightly more complicated to use than the diving watch bezel. Essentially, it converts the time (in seconds) consumed into speed (km/h). The specific method of use is this: You are driving, assuming your starting point is point A, there is a 1KM sign on the road ahead, we mark it as point B, so we can know the distance between the two points of AB is 1 km. When you start from point A, press the chronograph and the pointer starts to run. When you drive a section and see the 1KM sign, it means that you have reached point B, which means you just happened to drive 1 Kilometers, at this point, press the chronograph again, the pointer stops, and the reading it points to is the average speed of your driving during this 1 km.
What is the principle of this? First of all, we must be clear that at the beginning of the production, the speed measurement function is used by default at a length of 1 km. Then I give an example to illustrate the production process of the speedometer bezel: If the time spent 1km is 30 seconds, then the distance you can walk in 1 hour is 3600/30=120km. In other words, at this time you The speed is 120 km / h. Therefore, the speed scale of 120 is engraved in the position of 30 seconds, and the position distribution of other speed scales is similar. In this way, a speedometer circle is made. Understand the production principle of the bezel, as long as you think about it again, the principle of using the speedometer ben is not difficult to understand.
The scale corresponding to the 28 second position is 130 km/h. Since people run 200 meters instead of 1 kilometer, you only need to calculate: 130/5=26, you can get his speed of 26 km / h, which is very fast. Also, when your speed is constant, the speedometer bezel can also be used for ranging. For example, if you drive at a fixed speed of 120 kilometers, start the chronograph. When the pointer advances to the 120 km/h scale, you have already traveled 1 km. These are simpler examples, and there are more complicated calculations, which are not listed here.