US Patent 7562455 Automatic opening and closing knife

An out-the-front automatic knife incorporates dual locking and release mechanisms that define a three-point blade-handle interconnection between the blade and the handle when the blade is locked in the open position. A single trigger is operable to automatically open the knife, and to automatically close the knife. Separate firing and retraction springs may be provided with different spring strength to vary the speed and strength of the blade moving to the open position, and to the closed position. Blade guide systems cause the blade to travel longitudinally and linearly. The handle substantially encloses the blade and incorporates an access port to facilitate cleaning and maintenance of components housed in the handle interior.