PATENT EXPIRY VERIFICATION FOR APPROVED PATENTS

Question

Please advice if the following patents are still valid 1) US 4104966A and 2) US 3931884A

IS IT VALID IN INDIA OR EXPIRED AS ALREADY 20 YEARS PASSED?

Answer 1

This Wikipedia article describes the term of patents. From that article:

In the United States, for utility patents filed on or after June 8, 1995, the term of the patent is 20 years from the earliest filing date of the application on which the patent was granted and any prior U.S. or Patent Cooperation Treaty (PCT) applications from which the patent claims priority (excluding provisional applications). For patents filed prior to June 8, 1995, the term of patent is either 20 years from the earliest filing date as above or 17 years from the issue date, whichever is longer. Extensions may be had for certain administrative delays.

Both the cited patents were granted in the 1970s and would have expired 17 years from their grant date. As such both would have expired long ago.

Patents are specific to a jurisdiction. US patents are enforceable only in the US. They have no validity in India. There is always the possibility of an equivalent patent in other countries, but since the US patents are prior art and so old, I would guess the specific invention described in them couldn't have an active patent in India or anywhere else. This doesn't mean that there aren't other relevant patents so it is always a good idea to search more broadly. A good place to start are the patents which cite these patents here and here.

Please note, I am not a lawyer and this does not constitute legal advice.