I was wondering what a patents
Priority date is? If its set to 1997 and it has been published 6 times (the last publish was 2012) when does it expire?
The patent I am talking about is US20120221930.
US20120221930 is a pending application - not a granted patent. It has a lengthy history as set out at the beginning of the description:
"This application is a continuation of co-pending U.S. patent application Ser. No. 12/628,465, filed on Dec. 1, 2009, which claims priority under 35 U.S.C. §120 as a continuation of U.S. patent application Ser. No. 10/446,623, filed on May 28, 2003, now issued as U.S. Pat. No. 7,647,550, which is a continuation of U.S. patent application Ser. No. 08/712,586, filed on Sep. 13, 1996, now issued as U.S. Pat. No. 6,584,498, the entire disclosures of which are incorporated by reference."
It should expire on September 13, 2016 - BUT! And there are a lot of buts. First the application must be examined and a patent granted. Then any renewal fees owing must be paid. If these happen then the term is calculated to be 20 years from the first filing date - September 13, 1996. There is even another but. The term may be extended if there is a delay of more than three years in processing in the US patent office - calculated from the date the of the filing of this continuation, August 30,2012.
You can keep track of the application on the PAIR system at the USPTO.