Q: I just found out my grandfather had a patent. How could I research if his intellectual property has been used?

A: Your grandfather's patent is US2746620 and was granted in May of 1956. https://patentimages.storage.googleapis.com/0c/62/fa/ea6fb18d961575/US2746620.pdf

While your question centers on finding anyone using this technology, you may be wondering if anyone using the technology is paying a license fee (or should be paying) and if that money can flow to your grandfather's estate.

This patent was granted when the law allowed a 17 year span of protection for each patent starting from the date it was granted. This law changed in 1994 and again in 2011 to alter the lifespan of a patent, so be careful if you just Google "patent life span." You are not likely to get the right answer for a patent from 1956 unless you ask the question carefully.

Because your grandfather's patent protection expired in 1973, it will be next to impossible to find businesses and organizations using the technology now. Businesses are free to use that technology and don't have to pay money or tell anyone they are using it. You likely have no legal authority to stop anyone from using the technology or to charge money for using it.

If you are interested in your grandfather's legacy, however, look at patents US4659276 and US3746194. Both cite to your grandfather's work as precedent technologies, and both inventors had to prove that they did not copy your grandfather's work. Thus, your grandfather's impact on modern life continues to this day.

https://patentimages.storage.googleapis.com/73/4c/2e/4b7d54ef58ab0c/US4659276.pdf

https://patentimages.storage.googleapis.com/55/92/83/6a5005cf358a0c/US3746194.pdf