Constant-force tourbillon

Constant-force tourbillon

IWC integrated a patented constant-force mechanism into a tourbillon, which ensures that the amplitude of the balance – and thus the watch’s accuracy – remain absolutely constant, initially by disconnecting the escapement from the direct flow of energy generated by the gear train. The energy is stored temporarily in a balance spring and dispensed to the escape wheel. In the process, the tension in the spring is increased once a second and the seconds hand in the tourbillon advances in one-second steps. This ensures an extremely regular and precise rate over a period of at least 48 hours. After approximately 2 days, the mechanism switches from constant-force mode to normal mode, as indicated by the one-fifth-of-a-second movements in the seconds hand.