The Axis lock is based on a rod that passes through two liners and slides forwards and backwards in the slots in the liners.
The ultra lock is a variation of the Axis lick (sliding through slots) and I believe that Cold Steel pays a royalty to Benchmade for the rights to use the Axis patent (Williams & McHenry patent + additional Benchmade patents).
The Arc lock is a variation of Bob Taylor's "Rolling Lock" where the rod does not slide, but rotates in holes in two liners. I don't think that royalties are paid on the lock. The Rolling lock is now owned by Benchmade (sold to Benchmade by Bob Taylor).
Both lock designs can be made as strong as the manufacturer wishes to make them. Both locks have the ability to be very reliable.