Can someone who has more insight than me please explain how the patent laws work concerning the baskets? I know that the first patent was issued in 1977 and, for a while, only DGA produced baskets. How did it come to be that other firms began to produce baskets? Was the right sold to other companies? Did the patent expire?

This could potentially have some bearing on a situation here in Switzerland, so please don't chime in unless you really know - no speculation, please!

The DGA patent that specified an inner and outer set of chains expired in 2002. That's likely why Innova's first target before 2002 came out with one set of chains. The DGA patent that allowed the inner chains to slightly flare out to a bigger ring outside the outer set of chains at the bottom, like the classic Mach 3 style, expired in 2006. Not sure if any newer targets have attempted that design yet. As I understand it, DGA still has a patent in force on the slider chain support design but I'm not sure what the specifics are on that.

DGA used to have the patents proudly displayed on all their web site, but since many of them have expired they seem to have disappeared. DGA has at least two patents that are still in effect. (6494455 and 5868395).

The patents that have expired are

4039189 Flying disc entrapment device August, 1977 Headrick et al. 273/400
4461484 Flying disc entrapment assembly July, 1984 Headrick 273/400
4792143 Flying disc entrapment assembly December, 1988 Headrick 273/400

There are others that are assigned to other companies that are in effect, a number of which are for portable targets.

While trying to find the relevant patent numbers I stumbled across a patent for a round score disc golf score card that can fit in side a disc without being bent (20060234596). Very amusing.

Are patent laws internationally binding? Do you have to have a seperate patent for each country?

I'd say you need to ask a patent lawyer that question (or research on the Internet) since some countries agree to honor patents from other countires and some do not. Of course, the other consideration may be whether the target gets PDGA approval, if that matters.