This disclosure describes systems, methods, and apparatus for a locking folding knife having a handle lock and a safety switch arranged around and rotatable around a pivot axis of the knife. In an engaged position the switch overlaps at least a portion of the handle lock and prevents it from moving into an unlocked position. A spring, such as a wire form spring, can be arranged within a pocket of the switch, and when the switch is moved between engaged and disengaged positions the spring can be compressed generating a rotational bias on the switch urging the switch toward either the engaged or disengaged position.

A folding assembly having first and second members that are pivotally attached to one another. A locking pin is disposed through the first member and second member and selectively actuatable to unlock the pivoting and opening or closing of the first and second members relative to one another. A spring-assist mechanism includes a primary spring element and a secondary spring element which act in conjunction to successively apply an opening force to the first or second member as it is opened. The assembly also includes a close-assist mechanism for partially closing the first and second members relative to one another.

A folding tool such as a knife includes first and second spaced apart sidewalls with a blade pivotally attached to both sidewalls with a self-interlocking pivot pin. An opening in one sidewall includes a first, larger portion that receives an end of the pivot pin, and a smaller cylindrical opening that communicates with the larger portion through a slot. The end of the pivot pin slides through the slot and the sidewalls are rotated relative to one another to interlock the sidewalls. The knife may be easily assembled and disassembled without tools.

A folding knife including a handle, a blade having a cutting edge, and the blade is pivotably coupled to the handle about a pivot axis between a retracted position and an extended position. The blade is received within the handle in the retracted position and the cutting edge is exposed in the extended position. The folding knife further includes a liner between the handle and the blade. The liner has a resilient member that biases the blade toward the retracted position when the blade is in the retracted position and the resilient member biases the blade toward the extended position when the blade pivots in a direction from the retracted position toward the extended position.

Disclosed herein are embodiments of easily disassembled folding knives. In some embodiments, a folding knife includes a blade and a handle including first and second side portions. The first and second side portions can include respective locking elements which can be used to retain the side portions from lateral separation from one another. In some cases, the locking elements of one side portion include relatively narrow neck portions with relatively wide, non-circular head portions connected to the neck portions, and the locking elements of the other side portion include a recess and a corresponding non-circular opening. In some cases, folding knives can be provided with washers, liner lock mechanisms, and various other features.

A folding tool with improved locking features is provided. The locking feature comprises a substantially rigid member disposed between or proximal to a handle portion of the tool. The substantially rigid member comprises a bifurcated end forming at least one biased member for contacting a tang of the tool and securing the tool in at least one of a closed and an open position with additional locking features.

A folding knife incorporates an opening assist mechanism that functions to drive the blade from the closed to the open position and to retain the blade in the closed position. In one embodiment a spring arm located to one lateral side of the blade interacts at its forward end with a drive pin on a tang portion of the blade during a part of the blade's rotational path. The spring arm applies pressure to the tang of the blade through the drive pin when the blade is closed

Disclosed herein are embodiments of easily disassembled folding knives. In some embodiments, a folding knife includes a blade and a handle including first and second side portions. The first and second side portions can include respective locking elements which can be used to retain the side portions from lateral separation from one another. In some cases, the locking elements of one side portion include relatively narrow neck portions with relatively wide, non-circular head portions connected to the neck portions, and the locking elements of the other side portion include a recess and a corresponding non-circular opening. In some cases, folding knives can be provided with washers, liner lock mechanisms, and various other features.

A knife includes a handle and a blade that is rotatably coupled to the handle. A locking assembly is provided and includes a lock pin, an omega spring, and a transfer bar coupled between the lock pin and the omega spring for biasing the lock pin into a locking position to lock the knife closed or open. The locking assembly may further include a supplemental omega spring on an opposing side of the knife to further assist in biasing the lock pin into the locking position. A torsion bar is also provided within the handle to provide assisted opening functionality. The transfer bar extends at least partially through the handle to locate the omega spring in the handle offset from the torsion bar. The locking assembly assists with holding the blade in the open and closed positions, while the torsion bar aids in assisted opening and closing of the blade.

An acoustic resonator is cut, formed, or milled into the frame, or attached to the frame, of a folding knife to any dimensional specifications that support vibration at a desired sound effect frequency. The sound effect, sometimes referred to as shwing, schwing, ting or ping, is acoustically similar to the sound effect a Samurai makes when pulling his sword from its sheath or when he strikes another sword.