Improving mechanical-timekeeping precision is one of Breguet’s chief objectives, says brand CEO Marc Hayek. The Classique Chronométrie Reference 7727 incorporates three features designed to accomplish that. The first is a 10 Hz, or 72,000 vph, oscillator. Breguet introduced its first 10 Hz movement in 2010 in the Type XXII chronograph. The new 7727 is the first non-chronograph with a 10 Hz movement. Generally speaking, the higher the beat frequency of an escapement, the less it is influenced by external mechanical disturbances, such as shocks and the wearer’s movements. Most high-frequency watches suffer shortened power reserve, as the fast beat escapement allows the mainspring to unwind more quickly. The 7727 employs twin barrels to deliver a very respectable 60 hours of autonomy.
The second feature is a lightweight, nonmagnetic balance spring, pallet lever and escape wheel, all in silicon. The balance spring was developed specifically for this watch, and Breguet claims that it delivers “unequalled isochronism.”
The third, and most intriguing, precision-enhancing feature is the 7727’s use of two endstones incorporating powerful micro-magnets, one for each end of the balance shaft. This arrangement effectively reduces friction at the balance pivots to zero. This translates into some amazing rate results, according to Breguet. In tests, the balance wheel’s amplitude changes by only about 3 degrees between the horizontal and vertical positions, compared with the 40-plus-degree change seen in most movements, Breguet says. In an interview at Baselworld, Hayek said he hopes the reference 7727 will achieve timekeeping accuracy of -1 to +1 seconds in six positions, though -1 to +2 seconds would be acceptable.
Magnets are usually a no-no inside (or even close to) a mechanical timepiece, but the silicon escapement components eliminate the usual ill effects.
Breguet also says that we should not be worried about the balance pivots “floating free” rather than being firmly held in place by pierced or concave jewels, as in traditional constructions. The company explains, “As one of the magnets is stronger than the other, one end of the balance shaft is kept in permanent contact with its ruby endstone. Magnetic induction generates a magnetic flux through the balance shaft, developing a force that acts with the gyroscopic inertia affecting the balance shaft. If a blow shifts the pivot out of position, the magnetic attraction pulling it back increases with the extent of the pivot’s lateral displacement. The shaft thus returns automatically to its position, restoring the maximum magnetic flux.”
Hayek also noted that the magnetic pivots and silicon escapement components will likely find their way into other Breguet models in coming years.
Aesthetically, the reference 7727 is pure Breguet. The hours and minutes are off center, and the primary small seconds hand appears at 12 o’clock. At 1 o’clock, a patented small silicon hand indicates the 1/10s of a second. Ultra-light silicon reduces the rotating hand’s inertia and so its effect on the oscillations of the balance. The pare-chute shock absorber is visible at 2 o’clock as a reminder of Abraham-Louis Breguet’s 1790 invention. Finally, there is a power-reserve indicator at 5 o’ clock. Hayek said that the red “10Hz” lettering shown in the publicity image will not make it into the final production watch.
The dial is decorated with six engine-turned patterns. The center has Geneva waves, a clou de Paris design adorns the small seconds dial, the 1/10s-of-a-second counter displays a sunburst pattern, and the power-reserve indicator is decorated in chevrons. The chapter ring for the hours has an edging decoration and the outside rim is in a barleycorn pattern.
Though Breguet introduced the reference 7727 this year, deliveries to retailers will not begin until 2013, so production and pricing details have not been finalized. Hayek said he hopes to produce models in platinum and rose gold. Total production for the first year should reach “several hundred pieces,” he said. Hayek estimated that the retail price will be between 50,000 and 70,000 Swiss francs.
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