Well two things (I'm a lawyer, thought not a patent lawyer, but I have done some patent work).
(1) I'm pretty sure the term of patents was about 20 years -- think it still is, except for "design patents" -- so anything patented in the 1930s would have expired in the 1950s.
(2) Getting a patent doesn't mean the patent is valid. There are a lot of lawsuits from someone saying that he or she is the real inventor of something patented by someone else, and some of them are quite right. The Patent Office mostly relies on what the applicant says, though they do some additional research. How much the examiners would have known about recording technology, I have no idea. Maybe a lot. Maybe not much.
> On Aug 30, 2014, at 1:44 PM, Tom Fine <[log in to unmask]> wrote:
> As for 45-45, as I understand it, the whole reason Westrex could charge a license fee for all stereo cuts, in the 60s and I think into the 70s, was because they inherited the WECO patents from Keller et al from the 30s. Again, if Blumlein had exclusively "invented" 45/45, Bell Labs wouldn't have been granted a U.S. patent.