Abstract: An auto-disable safety syringe including a needle, a needle seat, a plunger, and a barrel. A cover of a needle seat chamber formed in the needle seat is provided with a splined hole having teeth and grooves. The needle seat has a ring block and an outer wall with splined teeth capable of passing through the grooves. A locking groove is formed in an inner cavity of the ring block and a locking head is formed on a connecting head to form a locking mechanism. Spiral grooves on the inner cavity engage with protrusions on the connecting head. When the locking head and the locking groove are interlocked and the plunger is retracted, the needle seat and the needle are retracted inside the barrel together. The syringe protects both patient and medical staff, is simple in structure, convenient to use and destructible.

Abstract: The present invention discloses an auto-disable safety syringe, comprising a needle, a needle seat, a plunger, and a barrel, in which a small top cover of a needle seat chamber formed in the needle seat is provided with a splined hole which is formed with plural protruding teeth and grooves, the protruding teeth are each provided with a limit boss, and the needle seat is formed with splined teeth, a seal is embedded in a neck between the splined teeth and the ring block. A locking groove formed in an inner cavity of the ring block and a locking head formed on a connecting head form a locking mechanism, the inner cavity is formed with spiral grooves and the connecting head is provided with protrusions for engaging with the spiral grooves respectively. The splined teeth and the limit boss connect securely the needle seat to the barrel. When the locking head and the locking groove are interlocked, the plunger is retracted, the needle seat and the needle will be retracted inside the barrel together.