Abstract: A safety syringe structure includes a combined structure of a syringe barrel, a needle retreater, a needle, and a plunger. The needle retreater and the plunger are slidably received in the syringe barrel. The needle retreater is arranged adjacent to the front end of the syringe barrel. The needle is coupled to the needle retreater. The plunger has an end extended to form a sharp tip and is provided with a plug facing the needle retreater. The sharp tip extends outside the plug in a direction toward the needle retreater. The sharp tip is movable with the plunger toward the front end of the syringe barrel to pierce into and couple with the through hole of the needle retreater; and the sharp tip is movable with the plunger toward the rear end of the syringe barrel to drive, through the needle retreater, the needle into the channel.

Abstract: A screw apparatus includes a shaft unit fastened inside a sleeve unit. The shaft unit includes a first end portion and a second end portion of a tapered shape. An outer diameter of the second end portion is greater than that of the first end portion. The sleeve unit comprises a holding portion, a locking portion and an expansion portion. The holding portion is attached onto the locking portion. An outer diameter of the holding portion is greater than that of the locking portion. The sleeve unit is locked onto an object with the locking members. A fastening unit is fastened onto the first end portion of the shaft unit to allow the second end portion thereof to move toward the expansion portion of the sleeve unit; thereby, the second end portion forces the expansion portion to expand outward in order to secure the sleeve unit onto the object.

Abstract: A safety syringe structure includes a combined structure of a syringe barrel, a needle retreater, a needle, and a plunger. The needle retreater and the plunger are slidably received in the syringe barrel. The needle retreater is arranged adjacent to the front end of the syringe barrel. The needle is coupled to the needle retreater. The plunger has an end extended to form a sharp tip and is provided with a plug facing the needle retreater. The sharp tip extends outside the plug in a direction toward the needle retreater. The sharp tip is movable with the plunger toward the front end of the syringe barrel to pierce into and couple with the through hole of the needle retreater; and the sharp tip is movable with the plunger toward the rear end of the syringe barrel to drive, through the needle retreater, the needle into the channel.

Abstract: A safety hypodermic syringe having a flexible safety cap covered on a hollow stopper around the arrowhead tip of the plunger, such that liquid medicine is completely forced out of the barrel through the needle cannula before forcing the arrowhead tip of the plunger into engagement with the connector holding the needle hub and the needle cannula for enabling the needle cannula to be received inside the barrel after the service of the safety hypodermis syringe.