Pregunte al mismo Dieter al respecto, copio su respuesta (su ingles tampoco es una maravilla, aunque infinitamente mejor que el mio
) y aprovecho para editar el primer post poniendo la imagen del reverso de la FC 20/70:
The 20/70 is a simple , but rare item. Yes I designed it personally.
It was the end of the slide rule era. The Copyright was 1976,
pocket calculators were dominant.
I tried to give a chance to our slide rule manufacturing with a model, which did calculate all problems, which were difficult or not so commode with the calculator. At first the five important slide rule scales again, then proportions as
> rebate deduction and additional,
> then the at that time very much used, but new "added value taxes" (Mehrwertsteuer),
> the gasoline consumption (Benzin-Skala),
> "sliding time " not fixed hours of work, noting by a time clock (Gleitzeit-Skala)
> and a table for weight female -Height-male
This "slide rule " was a flop , could not reach great sales.
The best business was with advertising imprint.
Jorge , I hope you find help eventually, otherwise a Friend of mine (in Chile) can translate.
my best regards
Dieter
Originales Saludos