An assisted-opening knife is a type of folding knife which uses an internal mechanism to finish the opening of the blade once the user has partially opened it using a flipper or thumbstud attached to the blade.[1]
When the knife is in the closed position, the blade is held in place by means of torsion springs and an additional blade lock (optional). As the user applies manual pressure to the thumbstud to open the knife, a mechanism such as a torsion spring moves along a track in the liner and rapidly rotates the blade into the open and locked position.[1]