Abstract: The invention is to provide a foldable knife comprising a flat handle and two opposite blades pivotably coupled to forward and rear ends of the handle respectively. The handle includes two resilient pieces on two opposite sides, each resilient piece being capable of being pressed by a hand of a user to fold or resilient piece is urged against a rear end of the blade for locking the blade in a closed or opened position. The knife further comprises a protective element disposed on the handle. The protective element has a height sufficient to prevent the cutting edges of the blades from contacting the hand of the user when the blades are in the closed position.

Abstract: The invention relates a foldable knife comprising a flat handle with a blade pivotably coupled to a forward end thereof; a central first opening through the handle; a resilient piece in the first opening extended from a distal end of the handle to a proximate end about the blade and having an upward slightly curved stop at an open end to lock the blade in the opened position; a second opening adjacent the first opening; and a gap disposed at an edge of the handle in communication with both the second opening and the outside. The gap can be pulled to be wide enough to allow an object (e.g., belt loop of pants) to pass through into the second opening for attaching the knife to a user.

Abstract: The invention is to provide a single blade foldable knife consisting of a planar-shaped handle section, a blade pivotably conjoined to an appropriate position at one extremity of the said handle section, and a protective component disposed on the said handle section at a position facing the tip of the blade cutting edge, such that when the blade is folded, the tip of the blade cutting edge is nested in the protective component, rendering the said cutting edge totally incapable of external contact and, therefore, the said protective component safeguards the user from injury due to touching the blade when the foldable knife is grasped, picked up, or carried, prevents the scoring of other objects by the cutting edge, and protects the cutting edge from wear due to other objects.

Abstract: The present invention relates to a foldable knife structure, which comprises a handle; a blade pivotably conjoined to a position adjacent to one end of the said handle; a set block adjacent to the pivotable conjoinment position of the blade and the said handle, with the said set block having a detent notch; a spring situated at the other end of the said handle, with the opposite extremity of the said spring extending to a position on the said set block. When the said blade is extended from (or folded into) the said handle, the said spring is against the circumferential edge of the said set block, causing the said set block to produce torsion that rotates the said blade out of (or into) a receiving slot of the said handle, causing the said blade to automatically bound out of (or fold into) the said receiving slot.

Abstract: The present invention relates to a foldable knife structure, which comprises a handle; a blade pivotably conjoined to a position adjacent to one end of the said handle; a set block adjacent to the pivotable conjoinment position of the blade and the said handle, with the said set block having a detent notch; a spring situated at the other end of the said handle, with the opposite extremity of the said spring extending to a position on the said set block. When the said blade is extended from (or folded into) the said handle, the said spring is against the circumferential edge of the said set block, causing the said set block to produce torsion that rotates the said blade out of (or into) a receiving slot of the said handle, causing the said blade to automatically bound out of (or fold into) the said receiving slot.

Abstract: A truncheon comprises an outer casing member including a smaller engagement portion on an outer end, at least two holes on engagement portion, and at least two detents movable in holes; a flexible sleeve sliding on engagement portion and including an inner peripheral limiting shoulder, an elastic member confined by sleeve and engagement portion being biased against the limiting shoulder, and a peripheral stop on outer casing member engaged with an inner end of sleeve in a storage position of truncheon; a handle extended from outer casing member; and a sliding rod in outer casing member. In use, after rod is unlocked pull rod outwardly from outer casing member until detents lock in first indented portion of rod. In storage, press sleeve laterally and inwardly until sleeve engages stop, thus permitting detents to clear from first indented portion prior to retracting rod into outer casing member until detents lock in a second indented portion or rod. This effects a smooth activation of detents.

Abstract: A retractable knife with a safety device to prevent the knife from being inadvertently extended once retracted, the knife comprises a blade having a first and second grooves on the opposite sides of the blade; a flat handle means including a first handle and a second handle with the blade pivotally disposed at and between the front ends of the first and the second handles in a first position for forming a receiving space; and a safety button having an arc member disposed at and between a second position on the first and the second handles adjacent to the first position. The safety button is operative to either insert the arc member into the first groove in an extended position of the blade or the second groove in the retracted position of the blade, thus locking the blade in the either positions.

Abstract: A folding knife with a blade having a bottom end edge and a handle grip portion. The blade is pivotally mounted at one end of the handle grip portion. The handle grip portion has a hollow slot. The folding knife includes a leaf spring with first and second ends and a protruding member. The first end of the leaf spring is connected to the handle grip portion and the leaf spring substantially extends along a length of the slot and the second end of the leaf spring is configured to abut against the bottom end edge of the blade and lock the blade firmly in place when the blade is fully extended out of the handle grip portion. The device includes a steel ball positioned on the protruding member and a cover plate having a through bore. The cover plate is mounted on the handle grip portion securing the steel ball between the protruding member and outer edges of the through bore.

Abstract: A retractable knife with single-edged blade comprises a handle of flat shape having a resilient member provided thereon; a blade hinged to handle; and an elongate protective member raised on the handle extended from one end to the opposite end along an edge thereof; wherein blade is engaged with protective member when blade is received onto handle such that blade is placed in a position away from reach of a user. By utilizing this, many advantages are offered such as user being not susceptible of hurt by the sharp blade when grasping or carrying knife, other objects being not susceptible of damage by the sharp blade when the objects are put together with knife, and the blade being not susceptible of wear due to a collision with the objects.