SJX Watches
Insight: The Advantages of a Vertical Clutch Chronograph
The vertical clutch has become the de facto standard in modern chronograph movements thanks to its mechanical and practical benefits. The widespread and varied use of the vertical clutch is illustrated by the many recent movements that employ the mechanism, ranging from the Rolex Cosmograph Daytona to the Breitling B01 to the MB&F; LM Sequential Evo. The proliferation of the vertical clutch is easily explained by its merits. Having explained the construction of a vertical clutch, we now turn to its advantages over the traditional horizontal clutch (or lateral coupling). Figure 1: A simplified cross section of a vertical clutch A vertical clutch serves to transfer energy from the going train of the movement to the chronograph going train, accomplishing this via a vertical motion. Figure 1 illustrates its key parts: a flywheel (yellow) geared to (or even part of) the going train; a cone (grey) that is linked to the chronograph seconds mobile, and vertically tensioned by a spring (red); a pair of pincers (blue) that engage with the cone, lifting or lowering the cone. When the cone is raised and engaged with flywheel, the chronograph starts running, and when the cone drops and disengages, the chronograph stops. One of the most apparent advantage of the vertical clutch is the low kinetic friction generated during coupling and uncoupling of the chronograph, as friction is produced only by the sliding motion of the pincers and the vertical motion of the cone. The Rolex Cosmogra...
