Disney, Microsoft, and other big companies throw their weight around,
legally or illegally, all the time.
Currently, the Red Hot Chili Peppers are suing Showtime over the term
"Californication" claiming that since they titled their 1999 album by
that name, they somehow own the word. I am sure I saw bumper stickers
as early as the 70's saying "Dont Californicate Washington" up here in
Washington State, but whoever can pay the most lawyers wins in the
end.

All that is a sideshow, however.

The more interesting question is-

Are there ANY plans available for building decent, commercial quality
sheet metal equipment?
Forget things as complicated and obscure as this cone roller- I have
never seen a reasonable plan for something as simple as a slip roll or
a finger brake.

I purchased the Gingery book on building your own brake- its a joke.
Where I live, minimum wage is $7.75 an hour- and I could work at
McDonalds, and make the money to buy a chinese import that would be 3
times the machine faster than I could build the silly Gingery brake.
It is designed, not to do the job, but to resemble a brake, made from
the cheapest materials in the easiest way.

There are a couple plans for Hossfeld knockoffs on the dropbox, but
they tend to ignore the features that make a hossfeld actually work,
and they are usually not compatible with Hossfeld dies, which seems
kinda silly.

I have seen a couple of plans for fixed, not slip, rollers, that are
very limited in size and capacity, and would again be more work than
just buying one from Grizzly.

The only "plans" on the internet I have ever found that were actually
worth using, were the CADPLANS for front end loaders for a tractor.
And they are far from free- I think I paid $150 for them. But when I
built the loader, it did everything it said it would, and 7 or 8 years
later, its still working away on my little Yanmar Diesel tractor. And
even buying new hydraulics, it cost about a third of a retail priced
new one.

But tools, especially sheet metal tools?
Who would draw such plans?
Why would they do it?
If they had the skill to design a brake, or a set of rolls, that did
not infringe on any existing patents, that worked well, and was
salable, why the heck wouldnt they just sell the tool, at a much
higher profit margin?
The CadPlans guy does not get rich selling his plans for $150, and yet
everybody complains.
To actually do decent plans for a finger brake, you would need to
build a few- make sure they work right, figure out true capacity,
etc.
And to do it right, you would need a decent machine shop, and probably
send out castings.
Suddenly, you are talking real money.

Sure, there are plans for model steam engines and trains- but these
are the hobbies of wealthy retired guys. And even then, most of them
require a decent machine shop.
If you have the money, and the skills, to acquire a machine shop,
chances are you will just buy a brake from Grizzly if you need one.

This cone roller is a bit different though- as far as I know, there
are only a couple of manufacturers in the world, and they get the high
prices for em- 1600 pounds is almost 3 grand US. I think the italians
may also make one, similarly priced.
Its a very small market, and they can get away asking these prices.
But because its a small market, there would be no market for plans-
how many could you sell? a dozen sets?

If you really need a machine like this, building one might be
feasible- but it would not be easy or cheap.

Another thing to consider is that the original poster is in the
Netherlands- where cheap tools are much harder to come by- here in the
USA, there are often deals to be found on old sheet metal equipment,
but in northern europe, they are rare and usually pretty expensive.
And there are far fewer cheap chinese imports available- Here, I would
start with a Jet or Grizzly rotary machine, for $500 or so, and turn
my own cones, and start from there- but in Europe, I dont know how
available, or cheap, the chinese sheet metal equipment is.

None of this answers his question, of course.
I would love to know of a source for good plans- but I really doubt it
exists.
Somebody prove me wrong.