Patent ID: 8016787

Claim:
Single-use syringe comprising: a barrel which has an inner surface which defines a chamber for retaining a fluid and an exit end through which said fluid may be expelled; a plunger which comprises an elongated body, said elongated body comprising a plurality of longitudinal ribs, and a piston which is connected to the end of the plunger close to the exit end of the barrel, the outer surface of the piston forming a fluid-tight connection with the inner surface of the barrel, wherein the barrel comprises at least two rings situated on the inner side of the barrel, at least one being situated on the distal part and at least one being situated on the proximal part of the barrel relative to the exit end, said rings having the general shape of a circular rim with an outer radius coinciding with the radius of the inner side of the barrel and a variable inner radius, and wherein each one of the longitudinal ribs of the plunger has a height which is constant along its entire length, but different from that of at least one of the other ribs, said height being suitable on each rib for allowing insertion of the plunger through the space defined by the variable inner radius of the said rings of the barrel in a close-fitting manner.