Patent ID: 6852096

Claim:
A safety device for a syringe, said syringe comprising: a body, a needle carrier mounted at one end of the body, a piston movable inside the body, and a piston plunger projecting from the body at its end opposite from the needle carrier and suitable for pushing the piston into the body towards the needle carrier, the device comprising: a sheath having a front end and a rear end, the syringe body being capable of sliding axially inside the sheath between an injection position in which the syringe body is fully contained within the sheath while the needle carrier of the syringe is flush with the front end of the sheath, and a safe position in which a portion of the syringe body projects from the rear end of the sheath while the needle carrier is set back from the front end of the sheath, the rear end of the sheath having a telescopic head, the telescopic head having a movable portion capable of taking up a retracted position in which it does not act on the syringe body when in the injection position, and an extended position in which it surrounds the portion of the syringe body that projects from the rear end of the sheath when in the safe position, a return member urging the syringe body towards the safe position, which return member is triggered automatically when the piston plunger is pushed into the body of the syringe, a combination for locking the telescopic head in the extended position, comprising two oppositely-directed axial bearing surfaces of the movable portion of the telescopic head which bear against two oppositely-directed axial bearing surfaces of the sheath, and two oppositely-directed lateral bearing surfaces of the movable portion of the telescopic head which bear against two oppositely-directed lateral bearing surfaces of the sheath, one of said lateral bearing surfaces of the movable portion of the telescopic head being radially outside one of said lateral bearing surfaces of the sheath.