Thanks. I think this explanation is the most accurate. From what I have read, Bill McHenry and Jason Williams hold the patent of the locking mechanism. They sold or licenced the right of exclusively using the locking mechanism to Benchmade, who named it AXIS lock. So the term "AXIS lock" (or "Axis lock" for that matter) is really the trademark of Benchmade.
Now that the patent has expired, any company or individual can put that locking mechanism on they folding knives (or their umbrellas if they wish) as long as they do not call it AXIS lock.
I think and hope we will see more than a few non-Benchmade knives with this locking mechanism in the near future.
If i'm not mistaken, there are many ways Benchmade/Bill McHenry and Jason Williams could keep it from being released in the public domain. Many companies have done this(not necessarily knife companies), but either way I wouldn't be surprised if this happened.