Patent ID: 8608694

Claim:
A new self-locking self-destroying safety syringe, specifically for use in medical treatment, comprising, a hollow barrel; a push rod sliding within the barrel; a rubber plug in front of the push rod; a needle seat in front of the barrel; the push rod is drawn backward to make the needle seat retract and be apart from the barrel after injection; the push rod is provided with a round platform, which is provided with at least one elastic ratchet that slantingly extends toward an inner wall of the barrel; the barrel is provided at a back end with an increasing-diameter portion; at a transient position between a normal-diameter portion and the increasing-diameter portion of the barrel is located a slanting step, and a groove is formed below and adjacent to the slanting step; when the push rod is drawn backward, the elastic ratchet passes by the slanting step and is caught in the groove; the increasing-diameter portion of the barrel is provided inside with a circlip; an external diameter of the round platform on the push rod is smaller than or equal to a minimal internal diameter of the barrel at the slanting step, but bigger than a minimal internal diameter of the circlip; and when the push rod is drawn backward, the circlip presses against the side of the round platform facing the push rod.