Abstract: A needle-protecting assembly adapted to be mounted upon the discharge extremity of the barrel of a conventional hypodermic syringe has a cylindrical hub adapted to hold a cannula needle of conventional construction. A transparent cylindrical sheath slidingly engages the hub. The sheath has a longitudinal slot and communicating detent, and a locking aperture. A tab radially emergent from the hub can be caused to engage the detent, slot or locking aperture, achieving respectively, a storage state where the sheath extends forwardly of the tip of the needle, a use state where the tip of the needle extends forwardly of the sheath, and an irreversibly locked disposal state wherein the sheath is forward of the tip of the needle.

Abstract: A protective needle assembly adapted to be mounted upon the discharge extremity of the barrel of a conventional hypodermic syringe has a cylindrical hub that holds an axially aligned cannula needle. A transparent cylindrical sheath slidingly engages the hub. The sheath has a longitudinal slot and communicating detent, and a locking aperture. A tab radially emergent from the hub can be caused to engage the detent, slot or locking aperture, achieving respectively, a storage state where the sheath extends forwardly of the tip of the needle, a use state where the tip of the needle extends forwardly of the sheath, and an irreversibly locked disposal state wherein the sheath is forward of the tip of the needle.