EXCHANGE NEEDLE AUTO RETRACTABLE SYRINGE

摘要

A safety syringe (11) incorporating a removal e auto retractable exchange needle assembly, the safety syringe having a syringe barrel (12), a hollow plunger (13) with a sling stopper (37) at a distal end, the needle assembly comprises a needle (16) with a needle hub (17), a gland nut (15) with a recess (25) to hold said needle hub and a spring (26) disposed over said needle hub and acting between said needle hub and said gland nut, a housing (29) disposed on one side of said gland nut to accommodate a dowel pin (30), said needle hub having a groove (31) around its circumference in which an end of said dowel pin mates so as to retain said needle hub in said gland nut during use, said plunger contacts said needle assembly upon completion of an injection and when further depressed activates auto retraction of said needle, causing said end of dowel pin to be dislodged from said groove to release said needle hub and said sealing stopper to be dislodged from said distal end of said plunger, allowing said needle and spring to retract inside said hollow plunger.