The Dopas 131 SC, which was produced in Schwenningen, Germany, and also known as Palmtag 131 SC, is one of the movements, which were most probably made in the 1940s and which were then forgotten because of World War II.
It is a Roskopf construction, which is a bit unusual for a german movement. Because of the construction, it has got one reduction step less than normal lever movements.
It makes extensive use of bearing- and cap jewels, to reach the number of at least fifteen jewels, which was important for advertising reasons. At the time being, 15 jewels were the common number for a quality pallet lever movement.
The gear train is typical for a Roskopf construction: The large, uncovered mainspring barrel covers even the center of the movement, and requires the hand driving works to be on the dial side alone.
After the mainspring barrel, there are only two reduction wheels, where the last one drives the indirect center second.
Finally, there’s a steel escape wheel.
The Dopas 131 SC uses a screw-less anular balance with three legs, which is of course not yet shock-protected.
The effective length of the hairspring, and hence the beating frequency of the balance, is adjusted by a long regulator arm.
As escapement, a pin lever is used.
Hour and minute wheel are both driven by a double gear, which is mounted on top of the mainspring barrel and connected by a slip clutch.
On the dial side, there are also cap jewels. For the balance wheel bearing, this is normal, but here, the bearing for the escape wheel is also covered by a cap jewel.
|Number of jewels:||15|
Nickel anular balance|
|Balance bearing / direction hairspring:||Counterclockwise|
|Adjust mechanism:||Long regulator arm|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||1 hole(s)|
|Functions:||hour, minute, (second)|
|Size:||13''' (measured: 30,4mm)|