Tourbillon

The most glossaries of watch terms describes a tourbillon (/tʊərˈbɪljən/; French: [tuʁbijɔ̃] "whirlwind") as a device in a mechanical watch that eliminates timekeeping errors caused by gravity, that is, compensating for the slight difference in the rates at which a watch runs in the horizontal and vertical positions. It was invented and patented by he French-Swiss watchmaker Abraham-Louis Breguet on June 26, 1801. Originally an attempt to improve accuracy, tourbillons are still included in some expensive modern watches as a novelty and demonstration of watchmaking virtuosity. The mechanism is usually exposed on the watch's face to show it off.

How does it work?

In a standard mechanical watch, the escapement is fixed, in models that are equipped with a tourbillon, the entire escapement is housed in a rotating cage, and the whole assembly is constantly moving, including balance wheel, escape wheel, and pallet fork (anchor); so that the effect of gravity cancels out when the escapement is rotated 180°. That means no matter what position the watch is in, those timing variations are essentially canceled out. The rate of rotation varies per design but has generally become standardized at one rotation per minute.

Types

Double-axis tourbillon

The double axis tourbillon was invented and patented in January 1977 by Anthony Randall. Later, in 1978, Richard Good constructed the first working model

As it can be understood from its name, the characteristic of this tourbillon is that it turns around two axes, both of which rotate once per minute. The whole tourbillon is powered by a special constant-force mechanism, called a remontoire. Thomas Prescher invented the constant-force mechanism to equalize the effects of a wound and unwound mainspring, friction, and gravitation. Thereby even force is always supplied to the oscillation regulating system of the double-axis tourbillon.

Double and quadruple tourbillons

Robert Greubel and Stephen Forsey launched the brand Greubel Forsey in 2004 with the introduction of their Double Tourbillon 30° (DT30). Both men had been working together since 1992 at Renaud & Papi, where they developed complicated watch movements. The Double Tourbillon 30° features one tourbillon carriage rotating once per minute and inclined at 30°, inside another carriage which is rotating every four minutes.

In 2005, Greubel Forsey presented their Quadruple Tourbillon à Différentiel (QDT), using two double-tourbillons working independently. A spherical differential connects the four rotating carriages, distributing torque between two wheels rotating at different speeds.

Triple-axis tourbillon

The independent watchmaker Aaron Becsei, from Bexei Watches, invented the world’s unique tri-axial tourbillon movement for wristwatch with traditional jewel bearings only in 2007. The Primus wristwatch was presented at the Baselworld 2008 in Basel, Switzerland. In the three axis tourbillon movement, the 3rd (external) cage has a unique form which provides the possibility of using jewel bearings everywhere, instead of ball-bearings. This is a unique solution at this size and level of complication.

Flying tourbillon

Rather than being supported by a bridge, or cock, at both the top and bottom, the flying tourbillon is cantilevered, being only supported from one side. The first flying tourbillon was designed by Alfred Helwig, instructor at the German School of Watchmaking, in 1920.