Abstract: A disposable safety syringe includes a barrel, a needle holder and a piston stem. Front end of the barrel is formed with an annular flange for a click hook of a needle holder to hook the flange and locate the needle holder. The needle holder has an inward extending coupling tube formed with multiple axially extending splits. A column section projects from front end of the piston stem will slightly expand the coupling tube. An annular binding groove is formed around the column section. The coupling tube is restricted by the wall of the binding groove to bind and tightly clamp the column section. The click hook thereof is pressed against a conic section of front end of the barrel. At this time, the click hook is converged and the engaging blocks are inlaid into the engaging channels to locate the click hook.

Abstract: A disposable safety syringe including a barrel, a needle holder and a piston stem. Front end of the barrel is formed with an annular flange for a click hook of a needle holder to hook the flange and locate the needle holder. The needle holder has an inward extending coupling tube formed with multiple axially extending splits. When inserted into the coupling tube, a column section projecting from front end of the piston stem will slightly expand the coupling tube. An annular binding groove is formed around the column section. When the coupling tube is accommodated in the annular binding groove, the coupling tube is restricted by the wall of the binding groove to bind and tightly clamp the column section. When the piston stem is forcedly pushed inward to drive the needle holder, the click hook thereof is pressed against a conic section of front end of the barrel. At this time, the click hook is converged and the engaging blocks are inlaid into the engaging channels to locate the click hook.