如何自动上发条的watch work?

I can remember when the firstquartz watchescame out, they were going to be the end of normal mechanical watches, just likevideo tapewas going to be the end of theaters. Somehow, it hasn't worked out that way, and self-winding watches are more popular than ever.

The following pictures show you the backside of a typical self-winding watch:

This watch happens to have a clear back so you can see inside. Highlighted in the second picture is a semi-circular metal piece that is the heart of a self-winding watch. Relatively speaking, this semi-circular piece is fairly heavy, and it is therefore affected bygravity. As you move the watch, this piece will move so that it is always pointed toward the ground. If you have time to load a 350-kilobyte MPEG file, thenthis six-second videowill show you how the piece moves. As you walk, with your arm swinging back and forth, this piece moves back and forth inside the watch.

附加到gear trainthat gears it way down. Each movement of your arm winds thespringthe tiniest bit, but since you move your arm so much it keeps the watch wound easily. The spring in the watch stores enough energy to keep the watch going for about a day and a half if you leave it on your dresser.