AS 736

Description

From the 1930s (the “Ebauches Trust” hallmark in combination with the old, round “ASSA” hallmark even limits it to the years 1936 until 1939) is the caliber AS 736, a stopwatch caliber with switching wheel.

It has got a diameter of 18 lignes and can measure up to 15 minutes, with a resolution of 1/10 second.

Since stopwatches usually have no long running time, the number of bearing jewels could be reduced to only four, which is enough for bearing the balance wheel axle. With the additional ruby ellipse and the two lever pallets, this movement uses a total of seven jewels.

The gear train leaves lots of space unused, but is constructed the usual way for a stopwatch. It uses the mainspring barrel, decentral (as position 12 o’clock) minute wheel, third wheel, directly driven center seconds wheel and steel escape wheel.

Since the frequency is twice as high as on a “normal” contemporary movement, but the usual gears were used, the center seconds wheel revolves twice per minute and the minute wheel only counts 15 instead of the on stop watches normally used 30 minutes.

As balance, a screw-less three-leg anular balance is used, which aesthetically reminds a lot of a cylinder movement balance wheel.

Of course, it is not yet shock protected (a pity!), and its beating frequency of 36000 A/h can be adjusted by a long regulator arm.

On the dial side, you see the two pinions for center seconds and minute cannon pinions, as well, as the switching wheel on the right, which is driven by a sliding mechanism.

The sliding mechanism works by pushing the crown and has got three states: Start - Stop - Reset.

The switch into the start position instantly moves the lever a position 6 o’clock, which has got a tiny pin to deflect the balance wheel, so that it starts beating without delay.

When the stop position is activated, the pin of the lever acts as a brake and immideatly halts the balance wheel. The reset position also halts it.

Technical data

Usage gallery