Junghans 628 stopwatch

The way the seconds are displayed is what I found interesting interesting and it is indeed what was most interesting about the movement design.

Movement with bridges and balance wheel removed

The movement has a pillar construction. On the mainspring barrel, you can see a system to avoid overwinding, which meshed with a gear on the underside of the barrel bridge.

Triple-layered escape wheel

The escape wheel is particularly interesting. The top gear is driven by the fourth wheel. The middle gear interacts with the pallet fork. The lower gear drives the seconds hand and has some longer teeth that enable the zero reset.

Seconds hand made visible

The seconds hand is divided in three so that as soon as one reaches 10 the next one appears at 0.

Dial side of the movement

On the dial side, there is a column-controlled mechanism with several hammers that interact with heart-shaped cams for the zero resets.

Heart-shaped cam for the zero reset
Zero-reset mechanism attached to the seconds hand