A pneumatic retractable syringe has a plunger having an interior retraction lumen. The plunger and syringe barrel have cooperating locking elements so that the plunger is locked after use within the syringe barrel. After injection of medication is completed, the needle is retracted into the lumen by compressed gas that is released from a gas cell within the syringe when the gas cell is ruptured just before the plunger reaches the end of its downstream path of travel.一種氣動伸縮式針筒,具有一推桿,其具有一內回收內腔。該推桿及針筒體具有共同作動的鎖固元件,以致於該推桿於使用後被鎖固於該針筒體中。在藥物注射完成之後,藉由在該推桿到達移動的下游路徑終止之前刺破該針筒中一氣室時將壓縮氣體自該氣室釋出,可將該針體回收於該內腔內。16...中心孔20...針筒22...基底23...刺叉元件24...內圓柱開口25...氣室26...長形中心頸部27...中心內開口28...內圓柱壁面29...隔壁30...凸緣31,32...腔室33...內圓柱壁面34...中心通孔開口35...針孔38...下游筒體開口43...針筒體44...針蓋45...銜接環46...穿孔器49...中心圓柱開口68...針口封閉薄膜69...穿孔器安裝座80...內氣腔
