Non esattamente, o almeno non proprio in maniera categorica, e sicuramente Il progettista di questo rasoio sapeva praticare l'eccezione misconosciuta di questa regola:
Siemens / SI.RA.MA.
Sembrerebbe una cosa pericolosa, ma cosa volete che sia, è stato brevettato nello stesso anno in cui Hitler diventò cancelliere !
https://www.technischesmuseum.at/langua ... ster=false" onclick="window.open(this.href);return false;
“Unlike the Klaro, the Siemens SiRaMa (Siemens-Rasier-Maschine) has been a rather popular electric safety razor on the continent of Europe. In 1932 Siemens announced in "Siemens Mitteilungen", the company's house organ, that the company marketed a new shaver. Unlike many other brands in the 1930s the SiRaMa has a real moving blade, so not the complete razor is vibrating, but only the blade. A triangular spindle, driven by a very small real motor, pushed the razorblade slightly to and fro. The razor took power from a 4.5 Volt battery (in a separate box) to prevent electric shocks from the mains. With the razor Siemens also marketed a blade sharpener. The razor was based on a patent of Georg Biniek of Berlin (DE) and has been manufactured until about 1938.”
https://pedewei.home.xs4all.nl/ebndnofr.ht" onclick="window.open(this.href);return false;