Early in the 1970's, Argus/Cosina introduced the first Pentax thread-mount fully automatic SLR, using standard M42 single-pin lenses and slight pressure on the shutter release button. The meter switched on, the lens stopped down ever-so-quickly, and the proper shutter speed was obtained, automatically. Cosina also badged it as a GAF (Ansco) model.
This Alpa is, I believe, based on that same design.