It is interesting to see that the chronograph module is identical to what one can find in most column-wheel chronographs, but that the base movement is simplified as the device does not display the time. Not having to have a base module with a centre wheel turning once per hour and a fourth wheel turning once per minute allowed the designers to have a decentralized main wheel and do without a third wheel. This also meant that the keyless works only needed to provide a winding function and could therefore be simplified.
Dial with stop watch function only
Dial removed
The click and spring are on the dial side
The minute counter is above the crown wheel and the staff goes through its centre
Only the external ring of the crown wheel moves
Full chronograph function
Balance wheel
The driving and intermediate wheels
The underside of the balance wheel
The column wheel
The bridge holds the seconds and minute wheels
Bridge removed
The intermediate wheel is attached to a lever also acting as its own sping
Heart shape cam making the return to zero possible
The seconds wheel has a finger that pushes the intermediate wheel once per minute
Driving wheel removed
Intermediate wheel
Column wheel and its acuating lever
Column wheel
Chronograph plate with only the actuating lever left
