RETRACTING NEEDLE SYRINGE

摘要

Retracting needle syringe (20) includes barrel (22) having chamber (24), open proximal end (25) and open distal end (26). The plunger has an elongated cavity (34) in its distal end and a sealing cover element (35). Needle assembly (40) includes needle cannula (41) having inner hub with distal end connected so that the lumen is in fluid communication with the chamber. A flange on the inner hub is connected to an outer hub and a spring is contained between the hubs. A release element is movably connected to the flange and has a sharp proximal end projecting into the chamber. Distal motion of the plunger causes the sharp proximal end to cut through the cover element and the release element to dissociate an outer portion of the flange from an inner portion of the flange allowing the spring to expand and move the needle cannula into the cavity.