Trademarks are completely unrelated to patents.
But the US has the same bureaucracy for both. And bureaucracies are leaky abstractions.
It's a huge pain (and pretty much requires lawyers, but you can do it yourself, if you are a masochist), and, in retrospect, not worth it. I suspect that why most companies use ™.
For other people who haven't, see https://en.wikipedia.org/wiki/Industrial_property