Gravity affects negatively the balance wheel, the pallet fork and, especially, the hairspring in luxury watches.  The tourbillon was created circa 1795 by Abraham-Louis Breguet, when he was looking for a way to minimize the effects of gravity on a watch and improve its accuracy: he mounted both the balance wheel and the escapement on a rotating cage.

His idea was effective but very delicate.  Tourbillons were eventually relegated to become a collector’s item, as they were expensive and required a lot of maintenance, but now they are making a comeback into luxury watches, as they are en example of craftsmanship,

Modern tourbillons are visible through a window on the dial of the watch, or there may be seen as a second hand on the face of the watch that rotates once per minute (although some tourbillons do go faster).  The concept is that the tourbillion must be beautifully displayed as an example of fine watchmaking.

Nowadays there are four major types of tourbillons:

The Double-Axis tourbillon turns around two axes, rotating once every minute.  It is powered by a ‘remontoire’, or constant-force mechanism.

The Double and Quadruple Tourbillions use two double tourbillons that work independently.  A differential links the four rotating carriages distributing the torque among two wheels that rotate simultaneously.

In the Triple Axis Tourbillon, the third cage offers the possibility of using jewel bearings instead of ball bearings.

The flying tourbillon is only supported on one side instead of being supported by a bridge at the top and at the bottom.

There are several different opinions about the accuracy of a tourbillon, but it certainly has its appeal as an expensive but interesting feature in a watch.  There are, of course, several knock offs, as Chinese manufacturers make a many tourbillon movements that are purchased as an incomplete or unassembled watch movement which are then added to the luxury watches, to comply with the Federation of the Swiss Watch Industry.  That way these fine watches can be sold as Swiss watches. Let’s hope that this doesn’t translate into a new Swiss watch crisis.