Patent US 5,240,307 is for a invention that my father created. And I see that the patent has lapsed due to non-payment of fees. I was wondering how someone can go about obtaining the patent.
In general, the owner would need to petition the USPTO to allow payment of the maintenance fee late on the grounds of "unavoidable" delay. An alternate reason, "unintentional" delay is easier but cannot be used after two years. In this specific case, the patent would have normally expired in 2012 anyway.