Locking system for hypodermic syringes

Claim 1

A locking system for hypodermic syringes comprising: a cylindrically shaped barrel having a first and a second end, wherein said first end is open and said second end is closed, with a brace having an aperture for receiving a hypodermic needle communicating with the interior of the said barrel; a cylindrically shaped piston, having a channel circumferentially located between the ends thereof, mounted in fluid tight relation with the interior wall of the barrel and adapted for axial translation within the barrel; a piston shaft attached to the piston and extending along the longitudinal axis of the barrel and beyond the limits of the first end of said barrel; a floating ring positioned within the channel of the piston engaging the interior wall of the barrel, and a plurality of spring biased detent means positioned peripherally around the barrel and adapted to extend into the barrel for engaging the channel of said piston, whereby dislocation of the floating ring by movement of the piston will allow the detent means to move into the cylinder and restrain the piston from further movement after the piston moves past the said detents.