Say it's the exact same mechanism as evacuation slides.

Patents in the U.S. since 1995 have had a term of 20 years, prior to 1995 it was a term of 17 years.

The slides were initially patented in 1956. In 1956 the U.S. patent term was 17 years; those patents expired in 1973.

But, let's suppose some advances were made and the specific valving mechanism was patented later. It would have had to have been invented and patented some time after 1995 to still be covered by a patent.

If it were patented any earlier, its term will have expired and the idea is now in the public domain, which means anyone can use the idea without paying anything.