Importance

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Abstract

A syringe system 1 for use with a prefilled injectate cartridge 9 comprises a hollow cylindrical barrel 2 having an outlet 3 at one end for passage of liquid to be expelled along a hollow pointed needle 5 by depression of a plunger 12. A protective sleeve 14 is mounted on the barrel 2 and is slidable along the barrel between a contracted position in which the needle 5 projects through an apertured end 15 of the sleeve 14, and an extended position in which the point of the needle 5 is located within the sleeve 14 to shield the point of the needle. Interengaging formations 22, 24, 26 on the barrel 2 and sleeve 14 are provided for retaning the sleeve 14 in the extended position, and a spring 19 is provided for resiliently biasing the sleeve 14 towards its extended position so that the sleeve 14 will automatically assume its extended position, and be retained therein by the interengaging formations 22, 24, 26, on release of pressure applied in the direction of contracting movement. Further interengaging formations 24, 23 are provided on the barrel 2 and sleeve 14 for retaining the sleeve in the contracted position to enable location of the needle 5 at the site of injection, the engagement of these formations being automatically released on depression of the plunger 12. Automatic shielding of the needle thereby takes place without requiring any specific operator action.

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First Claim