Beat me to it. Yes, a patent expires. However, things like Tank could be a Registered Trademark, which also creates another set of issues. However, unlike the @#$%^& @ Monster (Cable) who tried to sue anyone with Monster in their name back in the day. If you are in non-competing industries it is less of an issues. IIRC Monster tried to sue a Auto Transmission Repair company and Monster.com (the Job/carrer) company claiming they had exclusive rights to Monster. But I digress.
There is also something called Prior Art. You could not generically patent a "round" or "square" watch generically for example because it is too vauge and assumed that it has to be that shape to begin with.
In short, as long as a consumer is not "confused" or "mislead" into thinking they are getting the competing $$$$$$$ brands product, then they should be OK. Cartier vs RW on the dial is a lot different then say Cartier -vs- Kartier | Carier | Carrie, etc. Then there is clear potential for confusion.