| 摘要 |
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 retaininig 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. |
