WatchTime - August 2012

ing partner Victorin Piguet. The movement contained 19 jewels
and relied on a classic pincer mechanism with an additional column
wheel to control the split-seconds hand. This timepiece
was sold to Tiffany & Co. in New York on Oct. 7, 1924. The
early wristwatch rattrapante models used a button in the crown
to start the chronograph, to stop it, and to return its hands to
their zero positions. The split-seconds mechanism was controlled
via a button at 2 o’clock. These elaborate chronographs
had cushion-shaped gold cases; their dials sometimes included
tachymeter scales to measure average speeds.
Watchmakers began working on movement number
198.012 on May 11, 1925. This was a comparable Victorin
Piguet movement in so-called “Lépine” design, i.e., the runningseconds
subdial and the 30-minute counter were collinear with
the crown. The unusual feature of this timepiece, which was
sold on Jan. 4, 1927, is that all its operating elements were on
the left-hand side of its cushion-shaped case. These included a
little slide between the crown and the split-seconds button,
which was located at 8 o’clock. This slide enabled the owner,
who was probably a southpaw, to block the chronograph function
for added security.
HOW A CLASSIC SPLIT-SECONDS
MECHANISM WORKS
Split-second chronograph watches have
in the center of the dial a pair of seconds
hands to measure elapsed seconds. The
additional seconds hand, which sits atop
the principal elapsed-seconds hand, enables
the timing of intermediate intervals
of time – the laps of a car driving around
a racetrack, for instance – within a longer
period of time. When the chronograph is
switched on, both hands begin to move,
together, as if they were a single hand.
When the first interval ends, the watch
wearer stops the split-seconds hand,
notes the elapsed time, and then restarts
the hand, causing it to jump forward to
catch up with the principal hand, which
has been moving continuously since the
chronograph was started.
This requires a fixed but flexible connection
between the two hands. This connection
shouldn’t sap an unduly large
dose of energy from the movement’s
mainspring and is therefore a very delicate
one. The difficulties begin with
drilling the very long hole through the
staff of the chronograph’s center wheel:
this staff must be quite long because it
The third model in this series (number 198.018, with round
gold case no. 411.525) was shipped on Jan. 31, 1927 to New
York, where Tiffany sold it with its own name on the dial.
Another rattrapante chronograph (movement number
198.076) began in a cushion-shaped gold case in 1927, but
reappeared in a round case in 1935, perhaps because there was
no buyer for it. It left the manufacture one year later. There were
probably not more than a dozen of these very early split-seconds
chronographs.
The economic upheavals that shook the world in the 1930s
had a profound impact on Patek Philippe. A drastic decline in
extends through the entire movement.
Furthermore, the bore hole must be extremely
precise so that the even thinner,
even longer, and extremely straight staff
of the split-seconds wheel can turn with
minimal friction inside the cylindrical
opening. Any eccentricity or bend will
interfere with its proper functioning.
Watchmakers screw the so-called
“split-seconds heart” (colored brown in
the illustration) to the rear of the chronograph’s
center wheel. This wheel later cooperates
with the split-seconds wheel
(pale blue), which is affixed to the splitseconds
staff. The split-seconds wheel
bears the split-seconds lever (dark blue),
which has a little ruby roller on its free
end. A slender steel spring (green) presses
the split-seconds lever so firmly against
the double-hand’s heart that the ruby
roller, because of its shape, rests in the little
notch. This contact suffices to cause
the split-seconds hand to rotate along
with the chronograph’s elapsed-seconds
hand. An “X”-shaped pincers (red), controlled
by a column wheel, stops the splitseconds
hand. The finely toothed ends of
these pincers act like a shoe brake. If the
thicker parts on either side of this pincers
rest atop pillars of the split-seconds column
wheel (yellow), then the brake is released
so the split-seconds hand and its
companion rotate together.
When the user presses the
rattrapante button, the column wheel
turns and advances one position. The descent
of the thickened parts between the
columns closes the pincers (illustration on
the left). The two arms press against the
split-seconds wheel and thus stop the
split-seconds hand. In this instance, the
ruby roller runs along the circumference
of the split-seconds heart. When the pincers
reopen, the spring’s pressure guides
the roller into the notch in the heart, and
the split-seconds hand catches up with
the chronograph’s elapsed-seconds hand
(illustration on the right). As long as the
chronograph is running, this interplay can
be repeated as often as the user desires.
Split-seconds constructions also exist with
parallel pincers. The function is exactly reversed
in this case: prongs that descend
between the columns open the pincers.
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