Disposable safety syringe

A disposable safety syringe comprising:

• a barrel having a fore end, a rear end, and a retaining rim at the rear end;
• an injection needle fitted on the fore end of said barrel;
• a plunger which is slidable in said barrel from a syringe-filling utmost retracted position to a syringe-emptying forwardmost position;
• a stem which is fitted to said plunger for manually moving said plunger between the retracted and forwardmost positions, said stem including a rear end section protruding from the rear end of said barrel;
• a longitudinally slidable protective sleeve slidably fitted about said barrel which is movable from an initial retracted rest position in which said needle is exposed to an advanced safety position in which said needle is surrounded thereby so that said protective sleeve covers said needle;
• a clamping means for fastening said protective sleeve in the initial retracted position to said retaining rim of said barrel;
• a releasing means provided at said rear end section of said stem for disengaging said clamping means from said retaining rim when said plunger is manually driven by said stem at least almost to the forwardmost position such that said protective sleeve is movable to the advanced safety position;
• and
• a locking means for locking said protective sleeve in the advanced safety position after movement from the retracted rest position.