Abstract: A passively guarded, fillable injection syringe includes an adapter for holding the proximal end of a hollow needle. An inverted plunger is slidingly mounted on the adapter to establish a medicament chamber that is in fluid communication with the needle. Also, a substantially cylindrical needle guard is positioned on the needle for reciprocal axial movement under the influence of a spring which biases the guard and adapter in opposite axial directions. A mechanism is provided such that plunger movements that are required in a typical fill and inject procedure also function to control the position of the guard relative to the needle. Initially, the guard is locked covering the needle tip. A plunger movement unlocks the guard and retracts the guard for syringe filling and injection. Depressing the plunger to complete the injection releases the guard for distal movement under the spring force into a needle protecting position.

Abstract: A safety device for a sheathed injection syringe includes a needle guard having a dilatable opening at its distal tip. A plurality of slits are formed in the guard extending proximally from the distal tip of the guard to create the dilatable opening. When the guard is in the relaxed state, the opening is relatively large to allow the sheath to pass through the guard during attachment of the safety device to the syringe. A ring having a lug is positioned over the guard and is moveable to contract the opening. The contracted opening allows the syringe to be used at non-normal injection angles. A cover is provided having an aperture for engagement with the needle sheath and a slot for engagement with the lug. During withdrawal of the cover, the sheath is removed from the needle and the ring is moved, contracting the guard opening.