Image Number 2 for United States Patent #6679863.
A hypodermic syringe with a selectively retractable includes an elongate barrel having an open proximal end and a distal end that defines a receiver. The syringe has a hollow elongate plunger with an open proximal end and a closed distal end. 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 syringe 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 distal end projects distally outwardly. The syringe has an elongate spring disposed about the stem of the hub that is compressed between the flange and 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 facing 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.