Patent ID: 6409702
Filing Date: 2002-06-25
Classification: A61M

Abstract:
A safety hypodermic syringe comprising:a barrel having a receiving hole; a needle holder slidably and controllably disposed in said receiving hole of said barrel, said needle holder having an insertion hole, an inner tapered hole with a conical surface, a pull stop edge fixed between said insertion hole and said inner tapered hole, and a liquid transporting hole in communication with a hypodermic needle exiting from the inner tapered hole; a plunger slidably engaged in the receiving hole of the barrel behind the needle holder, the plunger having a rod body; an end of the rod body having a connection head with a conical front portion corresponding in shape to that of the inner tampered hole of the needle holder and a rear portion having two elastically deformable claws; wherein during injection the plunger slides in the barrel so that the connection head passes through the insertion hole of the needle holder compressing the two elastically deformable claws until the conical front portion of the connection head is fully engaged against the conical surface of the inner tapered hole of the needle holder, wherein the two elastically deformable claws then are released to engage the pull stop edge of the needle holder so as to permit withdrawal of the plunger from the barrel with the needle holder and movement of the hypodermic needle into the receiving hole of the barrel.