The Gentleman Magazine Issue 13 | February 2019 | Page 15
This system is inspired by the seasonal system from the
Japanese Edo Period (1603 – 1868), which divided day and
night into six segments, of which the length varied from day
to night and from one season to another. Clocks from this
period were equipped with a single or double foliot balance
enabling automatic changes in their operating speed. A similar
Japanese lantern clock from the very beginning of 18th century,
belonging to the Musée International d’Horlogerie based in
Switzerland, is exhibited on Vacheron Constantin’s booth at
the SIHH 2019.
Crucial to the operation of the Twin Beat® system is the mode
selector that operates on an all-or-nothing principle, allowing
only one balance to oscillate at a time. Additionally, the all-or-
nothing construction ensures that the switch is instantaneous,
with no lag when transitioning from one mode to the other.
This guarantees that the timekeeping operations of the calibre
3610 QP are never interrupted, even for a fraction of a second,
and that the time display remains as precise as possible.
Both the Active (5Hz, 36,000vph) and Standby (1.2Hz,
8,640vph) balances are driven by the same mainspring barrel,
which is the most efficient way of distributing energy and the
only way to have a single power-reserve indication. This high
prioritisation of efficiency is central to the Traditionnelle Twin
Beat Perpetual Calendar, particularly with the Twin Beat®
system and what it represents.
The other side of the Traditionnelle Twin Beat Perpetual
Calendar’s optimised energy consumption is its 1.2Hz
(8,640vph) Standby mode, which steps in during long periods
of stasis when the watch is laid flat and a high-frequency balance
would only drain the mainspring with no added advantage.
Putting the Perpetual in the Perpetual Calendar
In order to fully leverage the advantages of the user-controlled
Twin Beat® system in maximising the potential power reserve,
the perpetual calendar mechanism was reworked to use as little
energy as possible.
Jumping indications are notorious for their parasitic influence
on the balance of a movement. The energy requirements for
their jumps cut into the energy going towards the balance, and
in many cases the balance loses amplitude and the chronometry
of the entire movement is compromised. This effect can be
exaggerated in a watch with multiple jumping indications, such
as a perpetual calendar timepiece.
In the Traditionnelle Twin Beat Perpetual Calendar, Vacheron
Constantin has implemented instantaneous jumping
indications for the date, month and leap year. Simultaneously,
the jumping mechanism (patent-pending) has been completely
redesigned, utilising a sprung dual-gear compound system that
requires four times less torque than a conventional jumping
display. With this improvement, even at midnight on New
Year’s Eve when all three indications jump instantaneously, the
effect on the amplitude of the active balance is negligible.
Other Technical Challenges
In order to support the main features of the Traditionnelle
Twin Beat Perpetual Calendar — the blockbuster perpetual
calendar and the innovative Twin Beat® system — a number of
other mechanical issues had to be addressed.
range of oscillator frequencies for the first time. In doing
so, new in-house areas of research and development were
opened concerning the fundamental principles of mechanical
timekeeping regulation.
As a result, a new hairspring was created specifically for
the needs of the highly sensitive Standby balance (1.2Hz,
8,640vph), with cross-sectional dimensions of 0.0774mm by
0.0159mm, comparable to the finest examples of human hair.
The hairspring of the Standby balance is nearly four times
smaller in cross section and exponentially more delicate than
the hairspring of the Active balance (5Hz, 36,000vph).
Although the display of the hours and minutes may seem to be
the most straightforward part of the Traditionnelle Twin Beat
Perpetual Calendar, they are far from simple or conventional.
Because the calibre 3610 QP has two balance wheels, only
one of which is allowed to oscillate at one time, the hour and
minute hands have to draw variable information from two gear
trains for one reading of the time. This is accomplished by a
gear differential that allows the hands to read more than one
input source of timekeeping data.
A second differential is mounted on the barrel for the dual
purpose of winding the mainspring and also reducing the
mainspring torque as it is directed towards the Standby mode
balance (armed with a delicate hairspring created especially
for the slow-beat balance). Two final differentials translate
the power reserve into the subdial that indicates remaining
mainspring wind.
Despite all this, the 480-component calibre 3610 QP measures
only 6mm in height and 32mm in diameter, an impressive
feat of micro-engineering on its own. With the Traditionnelle
Twin Beat Perpetual Calendar, Vacheron Constant further
expands its considerable savoir-faire in compact movement
construction.
Made by Design
Despite the pedigree of the classic case design in platinum
and the prestige of a high complication, the Traditionnelle
Twin Beat Perpetual Calendar deliberately embraces a modern
aesthetic take on age-old finishing techniques.
Movement plates and bridges are decorated with Côtes de
Genève and then treated with NAC, a dark coating that
offers superior resistance and durability compared with other
similar-looking treatments.
On the dial, the very 18th-century art of engine turning and
frosted finish are transmuted into clean radial guillochage
and sand-blasted surfaces. In order to perfectly achieve this
union of tradition and modernity, the dial is made in two
main segments in a multi-stage process. A gold dial segment
is decorated with hand-guillochage, and then fitted within an
outer segment of sapphire crystal. Gold hour indexes are then
set into the sapphire-crystal dial segment, which is further
laser-engraved and ink-filled for a sleek, seamless appearance.
This balance of classic case design, combined with contemporary
dial and movement aesthetics, complements the underlying
theme of the Traditionnelle Twin Beat Perpetual Calendar —
unequalled historical savoir-faire channelled through timeless
innovation.
With the Traditionnelle Twin Beat Perpetual Calendar,
Vacheron Constantin has moved beyond the conventional
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