Hypodermic syringe assembly

Claim 1

A hypodermic syringe assembly which comprises a disposable injection unit and a reusable plunger unit adapted to cooperate to dispense medicament from an elongated medicament-containing cartridge positioned in the injection unit; said disposable injection unit comprising an elongated barrel closed at its front end and open at its rear end to provide a mouth for receiving said cartridge, said barrel comprising a hub structure at its front end for receiving a hypodermic needle and a plurality of angular spaced elongated and resilient guides extending rearwardly from the hub structure, said guides being radially flexible with respect to one another at the rear of said barrel, and a double pointed hollow needle mounted in said hub with its front end extending outwardly of the barrel and its rear end extending inwardly of the barrel; said reusable plunger unit comprising a plug having means to simultaneously circumferentially engage the interior and exterior of said barrel at the mouth end and adapted to fit in the mouth of said barrel and be locked in circumferential and axial engagement therewith, and an elongated plunger passing longitudinally through said plug whereby an elongated medicament-containing cartridge having a piston at its rear end axially slideable therein may be inserted in said barrel through said mouth, said plug may be positioned in said mouth in radial and axial engagement therewith, and said plunger may be engaged with said piston for advancing and retracting the piston to aspirate and dispense medicament from the syringe.