Vertical Clutch

Definition

The coupling that connects a chronograph to the running movement by pressing two friction discs together on one axis, rather than swinging a toothed wheel sideways into mesh. Because no teeth have to align, the chronograph seconds hand starts cleanly from a standstill instead of stuttering, and the chronograph can be left running indefinitely without disturbing the watch's rate. The cost is height: the clutch sits in the middle of the movement rather than on top. Rolex built the 4130 around one in 2000, and the Breitling B01, the Omega 9300, the Audemars Piguet 4401 and the Frédéric Piguet-based 2385 and Omega 3313 follow. Paired with a column wheel, it is now the majority architecture in this library.