The Felsa Bidnator was one of the first automatic movements with bi-directional winding. Compared to the AS 1250, one of the earliest automatic movements, the automatic mechanism is far better designed and more robust (and therefore much easier to take apart and put back together).
The model deconstructed here is a Felsa Bidynator 690, which is from the late 1940s (the first Bidynators were introduced in the early 1940s).
Full movement including movement ring
Rotor moved to the other side to reveal the automatic bridge
Movement ring removed
Rotor
Rotor engraving
Underside of the rotor
Rotor removed revealing the automatic bridge
Click and spring on the underside of the automatic bridge
Automatic bridge removed revealing the automatic system
The upside-down L shaped element has a pivot at the end of its longer side and a pinon at the other end.
The pinion at the end of the L-shaped element is in contact with one or the other or the reverser wheels depending on the winding direction
Reverser wheel
L-shaped element with its pinion
The reduction wheel going under the balance bridge interacts with the mainspring barrel underneath
The pinion of the reduction wheel winds the mainspring barrel through the ratchet wheel
The reduction wheel is removed, showing where its pinion would mesh with the ratchet wheel
Mainspring barrel
The mainspring barrel has 2 sets of teeth, one connected to the reduction pinion and crown wheel, the other connected to the centre wheel
Gear train
The third wheel is connected to the seconds pinion and the centre wheel, which are on top of each other
With the mainspring barrel removed, you can see the centre wheel pinion below the bridge and the seconds pinion above, which is connected to the third wheel
