Tourbillon

Uncommon card · No. 90296

In chronometry, a tourbillon (; also tourbillion, ) (French for 'whirlwind') is an addition to the mechanics of a watch escapement to increase accuracy. Conceived by the British watchmaker and inventor John Arnold, it was developed by his friend, the Swiss-French watchmaker Abraham-Louis Breguet, and patented by Breguet on 26 June 1801. In a tourbillon the escapement and balance wheel are mounted in a rotating cage, with the goal of eliminating errors of poise in the balance giving a uniform weight. Tourbillons are still included in some modern wristwatches, where the mechanism is usually exposed on the watch's face to showcase it. Historically, Breguet's tourbillon was conceived to counteract the adverse effects of gravity on a pocket watch's regulating system, particularly in vertical positions. Pocket watches were typically worn vertically in waistcoat pockets, which led to gravitational distortion of the hairspring. The tourbillon aimed to average out these positional errors by rotating...

Read on Wikipedia · Image Eric Kilby from USA, CC BY-SA 2.0