ETA 2772

Description

In the end of the 1960s, the caliber series ETA 2750/2770 debuted. To this series also belonged the selfwinding caliber ETA 2772, described here.

As most ETA gents' calibers, this one has got the usual diameter of 11 1/2 lignes.
It’s also usual for ETA calibers, that they are of a good quality and that all important bearings contain rubies.

The ETA 2772 has got the standard ETA gear train, which drives the hands indirectly on the dial side by the third wheel.

The large mainspring barrel drives the seond wheel, followed by third wheel, center seconds wheel and steel escape wheel.

The very large, golden toned Glucydur balance with three legs is of course already screw-less. It is beared between two Incabloc shpck protections and beats semi-fast with 21600 A/h, which can be adjusted with a long regulator arm.

Unfortunately, on the specimen shown here, the hairspring and regulator is missing.

It’s typical for ETA to use a flyingly beared crown wheel, which can slip up and down. Into this wheel, the ratchet click engages, and not, into the much finer toothed ratchet wheel, which is here driven by the selfwinding mechanism, too.

The ETARotor selfwinding mechanism uses two pawl changers and two reduction steps. You can see, that the last reduction gear has got no own axle, but is hollow and beared on a massive axle.

Every owner of a modern ETA automatic knows, how this movement looks, when the oscillating weight is missing.

Here, the oscillating weight is axle-beared and doesn’t use a ball bearing.

The hands are driven by the drive of the third wheel at 8 o’clock, pretty near the center. The minute wheel uses a cannon pinion with a slipping clutch, mounted on the minute wheel.

The calendar mechanism consists of a switching wheel with a moveable finger, to be seen at position 10 o’clock. This construction allows an instant date change at midnight and a semi-fast collection by turning the hands back and forth.

The switching wheel of the calendar mechanism is driven by an intermediate wheel, which is mounted into the bridge, which covers the locking lever for the date ring and its spring.

The setting lever and the hands setting wheel are also covered, as well as the date ring on the opposite location of the first cover.

Technical data