in the same way nowadays we can address to a fast car as a Ferrari, or to a genial people as an Einstein.

Not so much in my enviroment. But there are other examples for what I think is the same effect:

• Tempo for all kind of handkerchiefs made of paper, not only the ones sold using that brand name (mainly in Germany)
• Kleenex (Germany, USA?)
• UHU for wet universal adhesives (Germany)
• Tesa or Tesafilm (Germany), Sellotape (Britain), Scotch Tape (USA, Canada) for adhesive tape, especially clear tape
• Selters for mineral water (Germany)
• Walkman for pocket-sized cassette players (Germany, worldwide?)
• Xerox for photocopier machines, the action of using them, and the generated copies (US, Canada?)
• Matchbox for die-cast toy cars (Germany, worldwide?)
• Kärcher for high-pressure cleaners (Germany)
• Google for any kind of internet search engine, and for using such engines (worldwide?)
• Vespa for any kind of scooter (Germany)
• Fön (named after Foehn wind) for hair dryers (Germany).

The Fön brand is a little bit unusual in my list. All other examples are still recognized as brand names, but Fön is not. It became a common word like radio or bread. Only experts still know it is a brand name that may get you in trouble when using it for hairdryers. The Fön / Foen brand was registered in 1909, bought in 1957 by AEG, sold including AEG in 1996 to Electrolux. While it is still in use, it is no longer aggressively used in marketing.

Asking for a Kärcher in a shop will get you a Kärcher machine, and nothing else. Asking for a Walkman will very likely get you a Sony machine. Asking for a Tempo might get you some cheap clone, especially outside shops. Asking for a Fön will get you any hair dryer, rarely one made by Electrolux.

The German orthography reform of 1996 changed the official spelling from Fön (the brand) to Föhn (like the wind Fön was named after). This might avoid brand name issues, and the context usually is so clear that you won't confuse the wind with the hair dryer.

Alexander