At the beginning of the 60ies, the movement manufactury Hermann Becker of Pforzheim, Germany released their last selfwinding movement, the caliber 313, called “Ultramatic”.
The HB 313 is a 11 1⁄2 ligne selfwinding movement whose rotor winds in both directions with a rocking bar winding system. It contains a contemporary two-leg ring balance, which is beared in two Antichoc S65 (or Rufa-Anti-Shock on the movement side) shock protection systems. The hairspring is connected to a moveable stud and can be regulated by a short regulator arm.
The selfwinding mechanism features a rocking bar changer, which drives the crown wheel via a friction clutch. This clutch decouples the selfwindig mechanism when the movement is manually wound.
The 25 jewel movement has got a directly driven center second hand and on the dial side a yoke winding mechanism and a number of cap jewels to reach the high nimber of 25 jewels.
The large date ring advances slowly and can be corrected semi-fast by turning the time back and forth.
During its production time, the movement was changed a bit, the (probably) older version which was marked with the old “HB” marking, had a massive balance cock.
|Number of jewels:||25|
Nickel anular balance|
|Balance bearing / direction hairspring:||Clockwise|
|Adjust mechanism:||Hairspring key|
|Winding mechanism:||yoke winding system|
|Setting lever spring:||1 hole(s)|
|Functions:||hour, minute, second, day, selfwinding|
|Size:||11 1/2''' (measured: 25,4mm)|
Flume: K3 207|