Abstract: The present invention is an improved needle holder for safety syringe, which is a needle holder formed through compounding two materials in one-time, in which rubber convex ring of high coefficient of deformation is formed on the step ring of holder, such that the convex ring can properly compress the ring slot at the front part of barrel. Further, a buckle ring is formed inside the holder, such that the buckle head of plunger locks the buckle slot after injection, and the holder as well as the needle are pulled back into the barrel when the plunger is pulled, thus prevents the needle from exposure.

Abstract: A needle holder used in a safety hypodermic syringe, including a hollow cylindrical body having a rear coupling structure adapted to receive a front retaining tip of the plunger of the safety hypodermic syringe with which the needle holder is used, wherein the needle holder has at least one movable unit and at least one engagement unit respectively connected to the hollow cylindrical body, the at least one movable unit being alternatively shifted between an extended-output status where the at least one movable unit is respectively disengaged from the at least one engagement unit, and an inwardly squeezed status where the at least one movable unit is respectively forced by an external force into engagement with the at least one engagement unit.

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.

Abstract: A safety hypodermic syringe is so designed that the needle assembly can be moved with the plunger assembly and received inside the barrel after the service of the syringe, and the plunger can be disconnected from the stopper and removed from the barrel for recycling. The barrel has an inside annular flange defining a plane not perpendicular to the axis of the barrel, so that the plunger is tilted in one direction after pulled to the back side of the barrel, preventing the stopper holder and the stopper from being pulled out of the barrel, and enabling the plunger to be easily disconnected from the stopper holder.

Abstract: A needle holder used in a safety hypodermic syringe, including a hollow cylindrical body having a rear coupling structure adapted to receive a front retaining tip of the plunger of the safety hypodermic syringe with which the needle holder is used, wherein the needle holder has at least one movable unit and at least one engagement unit respectively connected to the hollow cylindrical body, the at least one movable unit being alternatively shifted between an extended-output status where the at least one movable unit is respectively disengaged from the at least one engagement unit, and an inwardly squeezed status where the at least one movable unit is respectively forced by an external force into engagement with the at least one engagement unit.

Abstract: A safety hypodermic syringe is constructed to include a barrel, a needle assembly, a female connector, a plunger, and a male connector, wherein the female connector is disposed in the front end of the barrel and fastened to the needle assembly, having a rear retaining hole; the male connector is provided at the front side of the plunger and adapted to engage the rear retaining hole upon forward stroke of the plunger, for enabling the needle assembly to be pulled backwards with the plunger and received inside the barrel after the service of the hypodermis syringe.