One of Breguet’s headliners at Baselworld 2015 is the Tradition Chronographe Indépendant 7077. In this remarkable new chronograph, Breguet pulls off an unusual feat. Looking at the 7077, you’re actually seeing two watches at once. Or, to be more accurate, one timekeeper and one chronograph.
Within its 44-mm gold case, the 7077 has two entirely independent gear trains for its two primary functions. Unlike dual-escapement watches that use a differential to average out the rate of the two springs, the 7077 has no interaction between its parts.
Caliber 580DR is a manual-wind movement. The escapement for the hours and minutes beats at 21,600 vph, while the chronograph escapement is a high beat, oscillating at 36,000 vph. Both oscillators have been adjusted in six positions to optimize their rate. In order to best suit its different rate while keeping the wheels the same size, the chronograph’s balance wheel is in titanium. Both balance springs are silicon.
The running time can be read from the offset guilloché dial at the top of the watch. An unnumbered track runs around the flange: this tells the chronograph seconds, since the chronograph hand is the only one mounted at the center of the dial. Overlapping the running time display are two retrograde indicators: one for the power reserve, at 2 o’clock, and one for the chronograph minutes, at 10 o’clock.
Why does the chronograph minutes counter only reach up to 20? That’s a matter of the special chronograph escapement in the 7077. Although the 7077 has two escapements, it only has one conventional mainspring, which provides the 50-hour power reserve for the running time. The power for the chronograph comes from a flexed blade spring, which has a maximum reserve of 20 minutes. This spring is not wound; rather, every time you reset the chronograph to zero, the blade spring tenses, storing up energy for the chronograph’s next use.
The chronograph is controlled by two screwed-in pushers on the case middle, on either side of the lower lugs. These pushers, too, are unconventional: one of the buttons starts the chronograph, while the other both stops and resets it.