Abstract: The present invention of a self-destructive syringe includes a hollow needle barrel having a detachable structure disposed between a rubber head and a push rod located therein; a retaining ring is disposed in a proper distance at the front end inside the needle barrel; after the injection, the rubber head of the syringe stays fixedly on the retaining ring; then the push rod is pulled backwardly to separate from the rubber head to form self-destruction; furthermore, connecting tabs are disposed on two opposite areas on a bearing base such that the rod body makes the connecting tabs break via rotation or pulling after the injection thereby causing the rod body to destruct more completely so as to prevent any danger of reusing the syringe.

Abstract: A structural safety design for the prevention of mis-pressing plunger rod into syringe mainly designs for single-used syringes, of which set a locking socket and a safety locking tab at the plunger rod end. An obstruction is formed between the plunger rod and the flange of hollow fluid chamber before the safety locking tab is pressed into the locking socket, so that the plunger rod can not be thoroughly pressed into the hollow cylinger. The invention, therefore, provides with a safety structure that effectively prevents from the unable-to-use problem of a syringe resulting from the plunger rod is mis-pressed into the hollow cylinder engaging with other components inside before the fresh syringe being used.

Abstract: A safety hypodermic syringe is disclosed including a barrel and a needle cannula holder. The barrel comprises a stop ring suspended inside the front section thereof, and connecting ribs connected between the inside wall thereof and the stop ring. The needle cannula holder fastened to the front section of the barrel comprises a front extension hub holding a needle cannula, a plurality of wedge-like locating blocks protruded from the periphery of the front extension hub and stopped at the front side of the stop ring, and a shoulder stopped at the rear side of the stop ring. The needle cannula holder is constrained by an axial force exerted from the stop ring and connecting ribs of the barrel. After the service of the safety hypodermic syringe, the needle cannula holder is pushed more forwards to force the shoulder against the connecting ribs and to break the connecting ribs separate, for enabling the needle cannula holder and the needle cannula to be further pulled backwards into the inside of the barrel.

Abstract: A needle holder positioning structure for safety hypodermic syringe is disclosed, which includes a barrel, a needle holder with a sleeve, and a locating ring. The sleeve of the needle holder said sleeve has a front engagement section press-fitted into the inside of a front small inner diameter section of the barrel and a springy rear expansion section, the springy rear expansion section being expanded and positioned in between a shoulder and an inside flange in the barrel when a plunger inserted into the barrel to push the locating ring forwards and to force a front neck of the locating ring into a backwardly extended annular coupling chamber in the sleeve of the needle holder.

Abstract: A needle holder mounting arrangement for safety hypodermic syringe is disclosed, which includes a barrel, a needle holder, and an expansion ring. The barrel has an annular locating groove extended around the inside wall of the front small inner diameter section thereof. The needle holder has a front coupling section and a rear positioning section received in a front small inner diameter section of the barrel, the side openings, and the movable positioning blocks respectively connected to the inside wall thereof by a respective springy connecting strip. The positioning blocks are engaged with the locating groove of the barrel to stop the needle holder from backward movement accidentally after installation of the expansion ring in the needle holder.