US Patent 8490288 Folding knife blade with dual locking mechanism

A locking mechanism for a folding knife. The locking mechanism has a locking sleeve and an opposed locking bolt which are coaxial and biased to a locking position by a spring. In the locked position, either with the blade extended or folded, both a lug on the bolt and a surface on the sleeve engage a locking surface on the blade tang area. Simultaneous manual force must be applied by the user to oppositely release buttons on the opposite handles to move both the locking bolt and locking sleeve to positions to disengage them from the locking surface to allow the blade to be folded or unfolded.