There are many components in a watch, some of them even have hundreds of components. They are all working together in harmony. This article will explain how the watch makes the ticking sound. The image below will help you to visualize the text below.
The mainspring of the watch gets energy from winding the watch manually(1) or automatically by a rotor (2).
Basically, to make a mechanical watch to work is to unwind the mainspring (3) in a controlled and precise manner.
As it slowly unwinds, the mainspring transmits power to the three wheels of the gears train (4) to the escapement mechanism (5).
Each of the three wheels is geared in such a way that each runs faster than the one before, thus converting the power imparted by the spring into faster and faster motion.
Due to a physical law, each successiev faster moving wheel has less and less power. As the wheels progress toward the end of the power train, they are made lighter and smaller. At the end of the last wheel, the power has been reduced so low to the point that a piece of lint or hair can stop the motion.
The escapement mechanism (5) is not part of the gears train. It consist of the Escape Wheel and jeweled Pallet Fork which in turn, transmits impulses to the balance wheel and hairspring (6).
The escapement is the watch.s heart and the only thing that determines how fast the mainspring unwinds. It also means how good the watch can keep time. The teeth in the escape wheel are shaped in such a way that they engage the small legs(the pallets) of the pallet fork cause it rock back and forth.
The escape wheel teeth impacting on first one pallet and then the other. Back and forth, is what causes the ticking sound. This continues over and over until the mainspring finally unwinds after about 48 hours.
The dial train (7), positioned on the dial side of the movement, drives the hour and minute hands around the dial (8) to indicate the time. The calendar mechanism, when included,is also driven by the dial train.