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AS 1220

AS 1220AS 1220

Description

At the end of the 1940ies, AS launched the caliber AS 1220. It was a mens' watch movement, which is unique due to its special shape of the main bridge and the odd construction of the center minute indication.

 

Construction

gears and trainsgears and trains

The AS 1220 is regulated by a contemporarily slow beating (18000 A/h) screw balance. It is beared in two 3-leg-shock protection systems, which cannot be identified with absolut certaincy, but it's very likely, that they are Ruby-Shock bearings.

side view of the gearsside view of the gears

The center second is already directly driven, which was very modern for that time.

mounted minute wheel and transformation bridgemounted minute wheel and transformation bridge

After escapement wheel, fourth and third wheel, the next transmission step is not the second wheel, as you might think, but ......

transformation mechanism for the second wheeltransformation mechanism for the second wheel

... there are two transmission gears, followed by the second wheel, which is driven by the mainspring barrel. The construction seems to misfit here and also the optics doesn't match. You might think, that this originally belongs into the transmission of a selfwinding mechanism.

I can only speculate about the reasons for that mechanism, probably there was not enough space for a normal second wheel with large outer teeth.

base platebase plate

Although the minute pinion is not ruby-beared, the two ruby-beared additional transmission steps lead fo a total of 17 jewels.

dial sidedial side

On the dial side, there's the yoke winding system and the three-leg shock protection, most probably of the Ruby-Shock type. But since the movement was sold in Germany (hence the "D" hallmark), it is also possible, that it is a Rufarex shock protection.

 

 Technical data

ManufacturerAS
Caliber1220
Number of jewels17
EscapementAnchor with pallets
BalanceNickel screw balance
Shock protection(s)Ruby-Shock
Balance cock directioncounterclockwise
Hairspring studfixed
Regulator typeLong regulator arm
Movement constructionFork
Escapement wheel, Fourth wheel, Third wheel
z z Center wheel
Mainspring barrel
Winding mechanismyoke
Setting lever spring2 holes
FeaturesSCD
FunctionsHour, minute, second
Beats per hour18000
Size101/2''' (measured: 22,8 mm)
Image in Flume Werksucher 1949 I 43
AS 1220ASAS122010 1/2'''AS 122017 Jewels, 10 1/2''', 18000 A/h, SCD
Factsheet

 

In the lab

Since the specimen shown here was in a very good condition, it was not intensivly cleaned, but just simple cleaned and oiled.

 

On the timegrapher

For a more or less unserviced movement, the timing rates are OK. Since the balance amplitude is very well (visually "measured"), it is likely, that with a better poising of the balance and an adjustment of the beat error, the rates could be much better.

crown rightcrown right crown topcrown top crown leftcrown left crown bottomcrown bottom 
dial topdial top dial bottomdial bottom 

vertical positions
12 up  -50 seconds/day
3 up  -13 seconds/day
6 up  +3 seconds/day
9 up  -25 seconds/day
horizontal positions
dial down  +7 seconds/day
dial up  +10 seconds/day
timegrapher measurings
 

For a movement, which was many, many years in use, it performs very well!

Usage gallery

Felsus mens' watch  (with wrong dial inscription)Felsus mens' watch (with wrong dial inscription)