How to make sure something cannot be patented?
<p>Suppose I invent something and I want anyone to be able to use my invention for free. I can't afford to patent it and release it under an open source license. Can I make it unpatentable by simply publishing the designs online?</p>

<p>Yes. Doing that will make the invention &quot;known prior art&quot; for any person other than the inventor/publisher. In soem countries the inventor will have a grace period, and could file for a patent within that period, but no one else could. Once any such grace period is over, the invention is in the public domain, and no one can ever patent it. Submitting a paper about the invention, with a note on the URL where the design is posted to a relevant journal or professional publication would make sure that anyone in the field would have seen it (or at least have been likely to have sone so) and further reduce the possibility of a valid patent ever being issued for the invention.</p>

united-states patents