HYPODERMIC SYRINGE WITH SELECTIVELY RETRACTABLE NEEDLE

摘要

A hypodermic syringe with a selectively retractable includes an elongate barrel having an open proximal end and a distal end that defines a receiver with an inwardly projecting shoulder. The syringe has a hollow elongate plunger with an open proximal end and a closed distal end. There is an elongate plug extending distally in to the hollow plunger from the open proximal end forming an enclosed cavity within the plunger. The syringe has an elongate hub having a passageway therethrough, a distally extending stem, and a proximal flange with an engagement for engaging said barrel. The syrin ge has an elongate needle having a fluid path therethrough, a sharpened distal end and a proximal end. The needle is mounted in the passageway so that the sharpened distal en d projects. The syringe has an elongate spring disposed about the stem of the hub that i s compressed between the flange and the inwardly projecting shoulder of the receiver to provide a bias. There is a hollow sleeve sized to fit within the receiver over the elongate spring with a proximal sharpened end disposed in the groove of the flange. When a user applies a sufficient force, the hub is sufficiently moved distally in the receiver for the cutting edge of the sleeve to cut through the flange and the closed distal end of the plunger to expose the cavity for withdrawal of the needle into the syringe.