THE HISTORY OF BLANCPAIN

IN TIME
B
D
C
The system of the 24 hour wheel
and instant date change cam (Fig. 2).
This system starts with the pinion, A, located
on the lower quadrant of Fig. 2. This pinion
is driven by the hour wheel of the watch.
The reduction of the pinion converts the
once in 12 hour rotation of the hour wheel
to a 24 hour rotation. In turn the pinion
drives the wheel, B, which turns clockwise.
The clever element is the cam, C, which
is attached to the wheel, D. For virtually all
of the 24 hour period of rotation of the
wheel, B, the cam, C, and wheel, D, are
dragged around by the wheel, B.
The “connection” between the
two elements is accomplished
by the pin which is attached
to the wheel, D. This pin fits
through an oblong trough
in the wheel, B, and,
thus, almost all the time
sits against the counterclockwise
edge. As the
wheel, B, turns clockwise,
the pin sitting on
the edge of the trough is
pulled along.
Fig. 1
The entirety of the module 69 large date
mechanism. The number of components gives a
hint of the sophistication of its functionality.
CLEVER ENGINEERING SOLUTIONS ABOUND IN THE CONSTRUCTION
OF THE MODULE 69, A CAM CONFIGURED FOR INSTANT DATE CHANGE, TWO
PROGRAMME WHEELS, AND PROTECTION FROM BACKWARD CHANGES.