Combination, self-locking, disposable and desinfection syringe

The utility model relates to a combination type self-locking disposable sterile syringe. The utility model is characterized in that the upper end of an outer sleeve pipe and the outer side of a core bar have one combination type self-locking device; the combination type self-locking device is composed of a gland, a location block, and a locating plate; the gland and the inner side of a round disc of the outer sleeve pipe are in an interference fit; the location block is arranged on a muscle bone of the core bar; the locating plate is connected with three points which are respectively arranged on the lower surface of a push disc for the core bar, on the upper surface of a round disc, and on the core bar wall. When the utility model is assembled, the self-locking condition can be prevented. When the core bar can be pushed to the bottom, the location block bounds into a bevel opening slot in order that the self-locking condition can be realized. The utility model has the advantages of simple structure, easy use, and safety. The occurrence of a secondary reusable problem can be stopped.