In French, “tourbillon” translates into “whirlwind”. In the world of watches a tourbillion is an addition to a watches mechanics that allows it to counter the effects of gravity. In a mechanical watch the main cause of variance in time is the effect of gravity on the movement when the watch is placed in different positions. Developed around 1795 and patented by the French-Swiss watchmaker Abraham-Louis Breguet on June 26, 1801, the tourbillon concept moves the mounting of the escapement and balance wheel to a rotating cage. This ultimately aims to negate the effect of gravity when the timepiece is stuck in a certain position. By continuously rotating the entire balance wheel/escapement assembly at a slow rate (typically about one revolution per minute), positional errors are averaged out.
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.
Historical there are four main types of tourbillion:
- The double-axis tourbillion – This tourbillion turns around two axes, both of which rotate once per minute. The whole tourbillion is powered by a special constant-force mechanism.
- The double and quadruple tourbillions – The double tourbillion 30° features one tourbillon carriage rotating once per minute and inclined at 30°, inside another carriage which is rotating every four minutes. In 2005 the quadruple tourbillion was invented using two double-tourbillons working independently. A spherical differential connects the four rotating carriages, distributing torque between two wheels rotating at different speeds.
- The triple-axis tourbillion – 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. There are a few wrist and pocket watches that include the Triple Axis or Tri-Axial Tourbillon escapements. Examples of companies and watchmakers that include this mechanism are Vianney Halter in his “Deep Space” watch, Thomas Prescher, Aaron Becsei, Girard-Perregaux with the “Tri-Axial Tourbillon” and Jaeger Le-Coultre with the “Gyrotourbillon”.
- The flying tourbillion – 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 in 1920. In 1993 a semi-flying tourbillon was created with only an abbreviated carriage for the escapement wheel and pallet fork, the upper pivot of the balance wheel being supported in a sapphire bridge.
In modern times the tourbillion feature has become a feature of opulence and luxury with the vast majority of modern tourbillion watches being collector’s watches and premium timepieces. Indeed most tourbillion watches are produced by the luxury Swiss watch industry and as a result they are of exemplary quality costing vast sums of money. Nevertheless the recent renaissance of interest in tourbillons has been met by the industry with an increased availability of time pieces bearing the feature. Subsequently this has caused the average cost of timepieces with the feature to diminish, albeit that watches with tourbillion mechanics still remain more expensive then their quartz counterparts.