mechanical watch 
Set of geared wheels that reduce the force transmitted by a spiral spring to cause the watch’s hands to rotate.
Very hard stone (formerly a ruby, today a rock crystal) that resists wear; the rotation axle of a wheel rests on it.
Last wheel of the gear train with special teeth that causes the watch to operate regularly and continuously; it controls the movement of the other wheels.
Flat spiral spring that causes the wheels of a watch to move over a certain period of time.
Wheel that is connected to the hands and causes them to rotate on the dial.
Toothed wheel having only one direction of rotation; it is kept in place by the click.
Small lever that is engaged between the ratchet-wheel teeth and prevents it from rotating counter to its normal direction.
Part that rewinds the mechanism, consisting of a series of wheels.
Wheel that receives energy from the fourth wheel and drives the center wheel.
Wheel that transmits energy to the third wheel.