With a diameter of only 7 3/4 lignes (about 17mm), the ETA 1170 is one of the smalles ladies' watch movements with directly driven center seconds. For technical reasons, it built pretty high, so that it’s appearance is a bit chubby.
As usual, this movement too was available with different types of shock protection bearings. Besides the usual Incabloc shock protections, there was for example a version with the less common and probably less costly Ruby-Shock protection available.
The fact, that the base plate shows noticeable few ruby bearings, is an indication, that we have a multi-storey construction here, which is no surprise because of the small diameter.
The center minute wheel is directly driven by the mainspring and located below its own cock. This was state of the art at the time being. The dial side bearing has got no jewel bushing, only the bearing on the cock, which also works as bearing for the center seconds wheel.
To achieve a higher (and advertisable) number of jewels, this movement uses some cap jewels.
The gear train is also typical for the 1950ies: The mainspring barrel drives the center minute wheel, followed by thied wheel, center seconds wheel and (steel-) escape wheel.
In the side view, you see the unusual high building screws for crown- and ratchet wheel. While the use for the ratched wheel is understandable (manual winding and releasing with a screw driver without risk of damaging the wheels), it is superfluous on the crown wheel.
The ETA 1170 uses a swiss pallet lever escapement.
The shock protected screw balance beats contemporarily slow with 18000 A/h; its exact beating rate can be adusted with a long regulator arm.
On the dial side, the yoke winding system and the shock protection for the balance are visible, as well, as a partial minute scale, which was used to adjust the movement before a dial was applied.
|Size:||7 3/4''' (measured: 17,1mm)|
|Number of jewels:||17|
Nickel screw balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Long regulator arm|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||3 hole(s)|
Flume: 1949 I 33|