Abstract: A safety syringe has a hollow barrel, a plunger, a connector, a plug and a needle hub. The plunger has a protrusion extended from the plunger and along a longitudinal axis of the plunger. The connector is mounted around the protrusion of the plunger. Multiple limit stubs and multiple curved limit channels communicating with a corresponding notch with an inclined side-wall are respectively formed on the connector and a connecting chamber in a connecting tube of the needle hub. When the plunger is being pushed towards the needle hub, the multiple limit stubs respectively pass through the corresponding curved limit channel and are contained in the corresponding notch. The inclined side-wall of the notch will stably connect the limit stub so the plunger can stably retract the needle hub in the hollow barrel.

Abstract: A safety syringe has a hollow barrel, a plunger, a connector, a plug and a needle hub. The plunger includes a socket to mount the connector. The connector has a needle connector protruded from the connector to connect with the needle hub. When the plunger is pushed toward the needle hub the first time, the needle hub of the connector is hidden in the socket and the plunger can not connect with the needle hub. When the plunger is pulled back and the syringe is full of medical solution, the needle hub of the connector protrudes from the socket. Pushing the plunger again toward the needle hub can connect the plunger and the needle hub together and the needle hub can retract back in the hollow barrel.

Abstract: A safety syringe has a hollow barrel, a needle hub and a plunger. The hollow barrel has a distal end, a proximal end, a cone-shaped end formed on the proximal end with an opening. The plunger has a proximal end and a needle retractor formed on the proximal end. The needle hub with a needle is detachably mounted inside the proximal end of the hollow barrel and has an axial fitting to engage the plunger. When the safety syringe is used, the plunger connects to the needle hub and is pulled toward the distal end of the hollow barrel to draw the needle hub with the needle inside the hollow barrel to keep people from being hurt or infected by an exposed needle.