"I would be willing to bet that at some point all those things have been covered by different patents"
I agree, but whether they have been covered and whether they should have been are very different things.
"The company who patented a chair rocking mechanism would not be affected by the inventor who made a door with soft springs"
Probably not, given how messed up the patent system is, but if you read Thomas Jefferson's writings on patents, it isn't too hard to imagine him spinning furiously in his grave at where the patent system is now because of this sort of thing.
What the founding fathers considered "non-obvious" was a vastly higher standard than what is passed off as non-obvious these days (these days it seems like most people who talk about patents consider "non-obvious" to be about the equivalent of "could someone have come up with in in a minute off the top of his or her head?", but for Jefferson, et al, these "X but on Y" patents would have been considered laughably weak and extremely damaging to the public good.
I agree, but whether they have been covered and whether they should have been are very different things.
"The company who patented a chair rocking mechanism would not be affected by the inventor who made a door with soft springs"
Probably not, given how messed up the patent system is, but if you read Thomas Jefferson's writings on patents, it isn't too hard to imagine him spinning furiously in his grave at where the patent system is now because of this sort of thing.
See, for example:
http://www.let.rug.nl/usa/presidents/thomas-jefferson/letter...
What the founding fathers considered "non-obvious" was a vastly higher standard than what is passed off as non-obvious these days (these days it seems like most people who talk about patents consider "non-obvious" to be about the equivalent of "could someone have come up with in in a minute off the top of his or her head?", but for Jefferson, et al, these "X but on Y" patents would have been considered laughably weak and extremely damaging to the public good.