AS x56

Description

This cylinder movement, probably from the 1920s, has got a diameter of 9 3/4 lignes. Although the shape of its three-quarter bridge is pretty unique and although parts of the movement number can be seen on the dial side, it cannot be identified.

If you look in contemporary movement finders, you will recognize, that on the dial side, it looks exactly like a PUW 700. Only the movement side differs.

Interestingly, the AS 755 uses the same base plate (including identical ratchet mechanism on the dial side), but a differently shaped bridge.

The base plate already shows, that it is a pretty simple movement. It has got no jewel bearings at all on the base plate, and the depthing of the cylinder of the balance can be achieved by bending(!) the U-shaped cutout around the balance wheel bearing.

The gear train is typical for a cylinder movement: Mainspring barrel, directly driven center minute wheel, third wheel, seconds wheel at 6 o’clock (here without prolonged axle for a decentral seconds indication) and finally the steel cylinder escape wheel.

As escapement, a three-leg cylinder balance is used, whose balance wheel cock uses mainly for decorative purposes a jewelled bearing. On the dial side, there’s only a simple metal bearing with a metal capping plate. While the jewel is visually appealing, it does not help enough to achieve a sufficient accuarancy, and this applies also to the long regulator arm.

The balance beats with 18000 A/h, normally, these kind of movements are accurate not better than one minute per day.

The combination of U-shaped balance wheel bearing (with a metal plate instead of a cap jewel) and visible ratchet (instead of a simple metal spring) is pretty unusual and is nowhere found in the Literature for AS movements, but for PUW. And indeed, at least the dial side reminds strongly of that of an PUW 700, only the movement side shows larger differences.
A mystery…

Even enlarged, only the last two digits can be read, “5” and “6”.

Technical data

Usage gallery