Patent ID: 7806860

Claim:
A safety syringe having a retractable needle facility incorporated therein, the syringe comprising a barrel and plunger and needle assembly, wherein the needle is caused to retract into the barrel of the syringe upon completion of injection once it has been used, by means of engagement between the needle assembly and the end of the plunger, and wherein locking means is provided in the body of the syringe to engage the plunger once it is retracted after use, so that the syringe is rendered incapable of being used further, the locking means provided by a split bush located in the end of the syringe barrel from which the plunger extends and in which the bush is fitted after the plunger is inserted in the barrel and pressed into position in the barrel, wherein the split is made to fit around the shaft of the plunger and is made to reduce in diameter when so pressed into the barrel, and engages by snap fit in the internal region of the barrel and the locking means is provided by a bush having two spiral grooves, which mate with two lugs on the plunger which engage the spiral grooves when the plunger is retracted locking the plunger as it is twisted.