Patent ID: 6068616
Filing Date: 2000-05-30
Classification: A61M

Abstract:
A needle assembly for use with a reusable syringe for single use drug cartridges containing a liquid drug, the drug cartridge being closed at one end with a piercable diaphragm secured to the cartridge by a metal cap having a central opening therein, the needle assembly comprising,a needle body having a mounting means for releasably mounting the needle assembly in the barrel of a reusable syringe,a double-ended needle passing through and permanently attached to the body and having a first intake end for insertion into a single use drug cartridge by piercing the diaphragm and a second outlet end for delivery of the drug to the patient,the needle body being provided with a bumper post through which the first intake end of the needle passes, the bumper post being of a size to pass through the opening in the cap of a drug cartridge and having a generally cylindrical shape with a concave contact end face to provide a contact edge at the periphery of the bumper post capable of directly contacting an area of a surface of the diaphragm of a drug cartridge along the contact edge spaced away from the point of insertion of the first intake end of the needle through the diaphragm, the contact end face of the bumper post being capable of sufficiently deflecting the area of the surface of the diaphragm towards the interior of the cartridge to displace a volume of a liquid drug in a drug cartridge greater than an internal volume of the double-ended needle to the extent that any colored body fluid, such as blood, if present in the contents returned to the drug cartridge when the diaphragm returns to its resting position, is clearly visible.