In the late 1960ies, Otero launched their last series of selfwinding movements with excenter changer. It contained movements with different functions and different beating rate. The Otero 792 shown here was part of this series and is so one of the few and probably last selfwinding movements from Germany, which uses an excenter changer.
It bases on the manual wind caliber 742, which in turn bases on the caliber 74, adding a date indication.
The base plate shows, that all bearings, except those of minute wheel and mainspring barrel, are equipped with rubies.
The gear train is the old-fashioned one with directly driven center minute wheel. At that time, it wasn’t state of the art any more.
The gear train has got a directly driven center second.
The pallet lever movement of swiss type is controlled by a screw less anular balance, which is beared in two Incabloc shock protection bearings. It beats slowly with 18000 A/h and can be adjusted by the hairspring key with a prologed arm.
The selfwinding mechanism is on top of the movement bridge. This bridge is different to the manual caliber 742, since it is fixed with three screws instead of two.
The selfwinding mechanism is plain and simple and consists only of the click wheel and the excenter changer. This changer is moved by two ruby-rolls on the inner side of the oscillating weight. With its two pawls, it ensures, that the click wheel is permanently driven and only in one direction.
When manually wound, the pawls detach the oscillating weight.
The excenter changer has got two springy clicks and a rectangular frame, in which the two ruby rolls of the oscillating weight are located:
The two ruby rolls on the inside of the oscillating weight reduce wear and noise level during their permanently engagement with the frame of the excenter changer.
With the detached oscillating weight, you can see the simple but genious construction of the selfwinding system, which Otero advertized as “technically perfect” construction.
The date indication mechanism has got a correction ability by turning the hands back and fourth. Unlike the selfwinding mechanism, it is a complex construction with two springs with good flying abilities.
Besides that, there are no oddities on the dial side, and of course, the Otero 792 has got a yoke winding system.
|Number of jewels:||25|
Nickel anular balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Hairspring key|
|Construction type:||solid construction|
|Winding mechanism:||yoke winding system|
|Functions:||hour, minute, second, day, selfwinding|
Flume: K3 180|