Patent ID: 6796961
Filing Date: 2004-09-28
Classification: A61M

Abstract:
A safety hypodermic syringe comprising:a barrel, said barrel comprising a body and a socket at a front side of said body; a needle assembly, said needle assembly comprising a needle hub mounted in said front socket of said barrel, said needle hub having a bottom coupling hole, and a needle cannula forwardly extended from said needle hub outside said barrel; and a plunger and stopper unit, said plunger and stopper unit comprising a stopper fitted into said body of said barrel, and an elongated plunger backwardly extended from said stopper to the outside of said barrel and adapted to reciprocate said stopper in said body of said barrel, said stopper having a front engagement tip adapted to engage the bottom coupling hole of said needle hub for enabling said needle assembly to be pulled backwards with said plunger and stopper unit and received inside said body of said barrel; wherein said socket of said barrel has at least one small stub rod protruding from an inside wall thereof; said needle hub of said needle assembly comprises at least one sliding groove formed in the periphery thereof and respectively coupled to the at least one small stub rod of said socket, for enabling said needle assembly to be pulled backwards with said plunger and stopper unit and received inside said body of said barrel after a rotary motion of said plunger relative to said barrel, said at least one sliding groove each having two distal open ends through which said at least one small stub rod of said socket is moved in and out of said at least one sliding groove when said plunger and stopper unit and said barrel are rotated relative to each other, and a positioning portion on the middle between said two distal open ends for engagement with the at least one small stub rod of said socket, said positioning portion and said two distal open ends being disposed at different elevations.