On Tuesday, January 28, 2020 at 8:58:57 AM UTC-5, Tango Whisky wrote:
Le mardi 28 janvier 2020 06:20:29 UTC+1, AS a écritÂ*:
On Tuesday, January 28, 2020 at 12:10:26 AM UTC-5, Tango Whisky wrote:
Patents run for 20 years, so anything connected to Grob gliders will have expired long ago.

..... unless they get renewed.

Uli
'AS'

You can't renew a patent after 20 years. It becomes public domain, and that's it.

TW - that is generally correct and after 20 years, there is rarely any interest in continuing any protection. But sometimes, there is and a good patent attorney will figure out how to revitalize that protection by adding new aspects to the process or invention. It becomes basically a new patent that tries to cover as much of the old stuff which wasn't disclosed before plus the new stuff. That's why good patent attorneys make the big bucks they typically do. ;-)

Uli
'AS'