Abstract: A plunger anti-detachment mechanism incorporates with a syringe which includes a hollow barrel, a hollow needle held at one end of the hollow barrel, and a plunger adapted to coaxially travel through the barrel. The plunger anti-detachment mechanism includes at least a locking stopper radially extended on the barrel and at least a resilient arm, having a locking latch outwardly extended therefrom, radially extended from the plunger wherein the resilient arm is adapted to move from an unlocked position to a locked position. At the unlocked position, the locking latch is moved away from the locking stopper such that the plunger is capable of freely traveling through the barrel, and that at the locked position, the locking latch is extended to the locking stopper so as to block up an axial movement of the plunger with respect to the barrel and interlock the plunger with the barrel.

Abstract: A plunger anti-detachment mechanism incorporates with a syringe which includes a hollow barrel, a hollow needle held at one end of the hollow barrel, and a plunger adapted to coaxially travel through the barrel. The plunger anti-detachment mechanism includes at least a locking stopper radially extended on the barrel and at least a resilient arm, having a locking latch outwardly extended therefrom, radially extended from the plunger wherein the resilient arm is adapted to move from an unlocked position to a locked position. At the unlocked position, the locking latch is moved away from the locking stopper such that the plunger is capable of freely traveling through the barrel, and that at the locked position, the locking latch is extended to the locking stopper so as to block up an axial movement of the plunger with respect to the barrel and interlock the plunger with the barrel.

Abstract: A syringe with needle retraction arrangement is adapted for automatically retracting the hollow needle into a hollow plunger after use so as to prevent the used needle from contacting with anybody. The syringe provides a closure seat at one end of a hollow plunger, wherein when the closure seat is intentionally pushed towards a mounting seat affixed in a mounting portion of a hollow barrel, a pusher member, which is detachably connect with the closure seat, presses a tip head of a hollow needle as well as an O-ring thereon to slide towards a needle hub to compress a compression spring to store a resilient force.