They use at least two different types of shutters for Flexaret VI: Metax and Prontor SVS. Here how it looks like with a Metax:

Flexaret VI Automat.png

The word "automat" means you need not to cock the shutter separately from winding the film - just turn one knob until it stops and that's all. This prevents from double exposures, either intended or not. Meopta's swan-song, Flexaret VII, allowed you taking multiple exposures while being an "automat".