The problem with that explanation is that half of those patents were filed in the 1970s or 1980s and should be expired by now. So go through the expired ones an

The problem with that explanation is that half of those patents were filed in the 1970s or 1980s and should be expired by now. So go through the expired ones and so long as you don't infringe on the newer patents then it is ok to use it royalty free. That is the whole point of the patent after all - once it expires, everyone can benefit from the invention, not just the inventor and his/her customers.