btw: here is what katt was referring to as "the automatic winding mechanism" i.e. not the rotor...
THE AUTOMATIC WINDING
Because the automatic winding system of the Swatch automatic is characteristic of all ETA automatics, and because it has been widely imitated (with slight variations to circumvent patent rights), it is worth describing in more detail. The winding rotor, in this case a base metal piece, carries a
drive gear that directly engages the two click wheels. As illustrated at
right, the rotor mount uses ball bearings, a now common practice, but a design first developed by Eterna and adopted by ETA. The two
click wheels (illustrated
left) are responsible for the bidirectional winding,
transforming either direction of rotor movement into counter-clockwise winding of the mainspring. Each click wheel is comprised of a pair of wheels, one on top of the other. Each pair is connected by a
unidirectional click that lies between the two wheels. These directional clicks are the heart of the bidirectional winding. Both top wheels rotate continuously with the rotor drive. Because of the unidirectional click between each pair of stacked wheels, the lower wheel will rotate only if the upper wheel is moving counterclockwise (for the right click as illustrated left) or clockwise (for the left click). The two lower wheels are always engaged with each other and it is the
lower wheel of the left hand click wheel (as illustrated above left) that engages the first of the two reduction wheels that eventually leads to the mainspring barrel.
With reference to the illustration of the top plate at right,
(5) indicates the
click wheels;
(7) the first
reduction wheel;
(6) the second
reduction wheel;
(3) the mainspring barrel
ratchet wheel;
(4) the mainspring
barrel;
(2) the
transmission wheel that transfers power to the barrel during hand winding (from the
crown gear on the winding stem);
(1) the
stem; and
(8) the sprung button that releases the winding stem push piece to remove the stem from the movement. With corresponding numbers, the parts still attached to the automatic winding bridge (inverted) may be seen in the illustration at
left. The three lower jeweled pivots on the click wheels and first reduction wheel are visible here.
Note that there is no disengagement of the automatic winding during hand winding in this movement and that all automatic parts rotate during rotation of the crown, all the way back to the two click wheels. Additionally, on this movement the ratchet (to prevent unwinding of the mainspring) is actually provided on the transmission wheel rather than on the "ratchet" wheel of the barrel (visible to the left of the transmission wheel {2} in the illustration above
right).
I have prepared a pair of schematic drawings that clearly illustrate the two paths that automatic winding takes with clockwise and counter-clockwise rotation of the rotor. Please
click here to view these schematics and an explanation of the operation.