Shielded syringe

A shield assembly for a syringe having a cylindrical syringe barrel having an interior chamber, a needle secured at one end of said barrel, a plunger slidably received within the interior chamber, said shield assembly comprising:

• sheath means for preventing contact with said needle, said sheath means being slidably disposed on said cylindrical syringe barrel and movable therealong from a closed position surrounding said needle to an open position exposing said needle;
• locking means for releasably locking said sheath means in both the open and closed positions, said locking means comprising a tab disposed on an inside surface of said sheath means and an elongate strip member having one end thereof secured to said cylindrical syringe barrel and a pair of berms thereon for engaging said tab;
• and
• spring means for urging said tab against one of said pair of berms when the sheath means is in the open position and in the closed position.