Glossary

Mechanism is an old mechanism used in mechanical watches to solve the issue of uneven distribution of power from the mainspring as it transitions from fully wound to relaxed state. The fusee consists of a cone-shaped device connected to the mainspring barrel by a chain.

The purpose of the fusee and chain mechanism is to maintain consistent torque during the movement of the mainspring and ensure equal power distribution. The cone-shaped fusee allows the chain to wrap around it in a way that compensates for the decreasing torque of the mainspring as it relaxes. This results in equal power distribution to the gears of the watch, leading to improved timing accuracy.

Simply put, when the chain is tightened with the necessary force, it supplies the gears with sufficient rotational power to maintain timing accuracy. When the mainspring is in a relaxed state, the effect directed to the gears decreases, allowing the chain to compensate and distribute power evenly to the gears, ensuring the continuity of timing accuracy.