Mont Blanc MB 25.10, Руководство по обслуживанию

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Calibre MB R230
Exo Tourbillon Chronographe
Available in the Heritage Chronométrie and TimeWalker Collections
The calibre of the Exo Tourbillon Minute Chronographe combines two of the most important
chronometric complications: a chronograph for measuring short time intervals and a tourbillon of patented
design for absolute precision.
This calibre has a large balance-wheel oscillating at 21,600 vibrations per hour (3 Hz), located outside the
tourbillon cage. This innovative and patented mechanism is called “Exo Tourbillon” from the Greek prefix
“exo”, meaning “external” or “exterior”.
The advantage of this construction is that it allows the use of a smaller, and therefore lighter, cage, needing
less energy to drive its rotating motion. The rotating cage is also relieved of the weight of the screwed
balance: this technical feat further reduces the energy required since the balance, isolated from the rotating
cage, is not disturbed by the cage’s inertia. In addition, the calibre
features a stop-seconds
function that stops the screwed balance-wheel directly, by means of a small spring. Such a device rarely
accompanies a tourbillon and is very useful when the wearer wishes to make a precise adjustment, not only
of the hours and minutes hands, but of the seconds hand as well. This innovative design is built into the
chronograph calibre, manufactured in-house, which combines all the elements of a traditional chronograph
with a contemporary, high-performance construction: a monopusher model with a column-wheel, a precise
and efficient vertical clutch, automatic winding and a double barrel.
Its power reserve is about 45-50 hours and it ensures remarkable wearing comfort.
Calibre MB R230