Patent ID: 8172814

Claim:
A combination of a syringe plunger and a syringe rod configured to cooperate with said plunger, wherein said plunger comprises an engagement mechanism that retains a head of the rod at an end of an axial translational and rotary coupling of said plunger and said rod relative to each other; wherein said plunger comprises: a corresponding hollow cylindrical body with opposite cylindrical bases, and in which a dome closing one of the cylinder bases and an opening in the opposite base are defined; a circumferential groove provided around the cylindrical body of the plunger configured to accommodate a ring-shaped gasket, a seat provided inside the plunger and having defined therein a joint for the head of said rod; wherein said joint defined inside the seat of the plunger is formed by four longitudinal extensions, arranged along a circumference, mutually spaced apart by 90° and resiliently flexible in a radial direction towards an outside of seat; and wherein said rod comprises at a forward end configured to engage the plunger: a disc-shaped base from which a central cylindrical projection and a pair of arc-shaped projections, diametrically opposed and arranged externally of said central projection, extend axially upwards; a first pair of radial stops, radially extending from a forward base of said cylindrical projection; a second pair of axial stops extending from a wall of the cylindrical projection and joined to said disc-shaped base.