Patent ID: 6638248
Filing Date: 2003-10-28
Classification: A61M

Abstract:
A hypodermic syringe having;a barrel with an open end, a base end and an internal bore; a needle assembly including a needle base member located inside the bore and releasably engaged with the base end and a needle which protrudes through the base end of the barrel; a plunger slidable within the bore, the plunger having a piston releasably engaged therewith and a chamber having air evacuated therefrom, the chamber being sealed at one end by the piston; wherein the piston includes means for engaging the needle base member such that in use when the plunger is depressed and the piston approaches the base end of the barrel, the piston can engage the needle base member, the needle base member is released from the base end and the piston is released from the plunger such that the piston, needle base member and needle can be forced into the chamber by atmospheric pressure, wherein the needle base member is releasably engaged with the base end of the barrel by means of a split ring movable from an engagement position to a release position.