MECHANICAL RECORD / 007
A heartbeat in motion.
A single-axis, between-pivots tourbillon teaching arrangement. It is not a reconstruction of a Breguet, Blancpain or other named caliber.
What the sources establish
The balance and escapement travel in a rotating cage. The escape-wheel pinion engages fixed gearing while its axis travels with that cage. Power comes from the watch’s train; the fixed gear provides a reaction, not energy. The historical aim was to average certain position-related rate errors. Improved wristwatch accuracy is not guaranteed.
Breguet dates the patent to 26 June 1801. Its Marine 5887 manual documents a sixty-second cage, one example supporting the period chosen here.
Our teaching choices
The external fixed wheel has 120 illustrative teeth, and the escape-wheel pinion has ten. That makes twelve escape-wheel revolutions relative to the cage per cage turn. The carrier also rotates, so the escape wheel makes thirteen turns relative to the stationary plate. These counts are chosen for this model, not measured from a source.
A fifteen-tooth escape wheel advances half a tooth per beat: 360 beats per minute gives a 3 Hz balance and a one-minute cage. One shared clock coordinates the motion at every speed. The short release windows are smoothed; tooth and pallet contact are not a physical simulation.
What is simplified
The upstream drive train is omitted. Dimensions, clearances, tooth profiles, cage layout and spring geometry are illustrative. No forces, friction, inertia, positional-rate errors or accuracy improvements are calculated. The spring is a readable spiral and the balance follows an ideal oscillation.
Separate parts uses viewing offsets, not operating clearances. The heartbeat replay follows the cage; the gearing replay follows the orbiting shaft. The purpose replay represents an upright watch with a fixed downward gravity reference. None of these camera movements adds a mechanical motion.
Sources
Breguet · The invention, 1801 ↗
Blancpain · Inside the mechanism ↗
Reviewed 15 October 2026.
← Back to the exhibition