180 YEARS OF

1958
Focus
on Power
Reserve
CONQUEST
Even 30 years after the debut of
the first self-winding wristwatches,
many potential customers
were still skeptical about
them. Manufacturers sought to
dispel their skepticism by equipping
watches with power-reserve
displays. Longines, too, added
this useful indicator to its newly
developed 290 family of movements.
Self-winding Caliber 290,
which was first used in the Conquest
family of watches, was 26
millimeters in diameter and had
24 functional jewels, a direct central
seconds hand and a Glucydur
balance that completed
19,800 semi-oscillations per
hour. The special feature of sixmm-thick
Caliber 294 was that its
power-reserve display had a centrally
positioned disk onto which
a hand was printed (see illustration).
A central rotor wound the
mainspring in both its directions
of rotation via a ratchet wheel
changer. If the watch was worn
regularly, it would amass a 45hour
power reserve, the level of
which was shown on the indicator.
Unlike base Caliber 290, Calibers
291, 292, 293, and 294 each
had a date display at 12 o’clock.
e Milestones | WATCH HISTORY
1960
New
Movement
Family
CALIBER 340
Longines oered three top lines of automatic
watches: Admiral, Conquest and
Flagship. e brand-new 340 family of
calibers debuted in the very slim Flagship
in 1960. Its distinction lay in an ocenter,
ball-borne, heavy metal rotor with
a complete wreath of teeth. A patented
satellite wheel changer tightened the
mainspring for bidirectional winding.
Longines integrated the automatic module
into the 4.45-mm-thick movement.
e Glucydur ring balance vibrated at a
pace of 19,800 semi-oscillations each
hour. Calibers 340, 341, 342, 343 and 345
each had a directly propelled central
seconds hand; minor technical improvements
were incorporated into versions
342, 343 and 345. Calibers 350, 351, 352,
353 and 355 did not have seconds hands.
A date display in a window distinguished
versions 341, 343, 345, 351, 353 and 355.
e base movement (Caliber 340) had
243 components, which were manufactured
by machine in a 960-step process.
is family of calibers was used in the
very classical Flagship line in 1960.
LONGINES SPECIAL WatchTime | 81