Disposable self-destructible syringes which render themselves unreusable

Claim 1

A disposable syringe which renders itself non-reusable, which comprises a rigid cylinder coupled at one end to a bottom wall with an opening for the exit of the solution to be injected, and having the other end open, said end being integrally coupled to support flanges which extend outwardly and perpendicularly to the axis of the cylinder, and a plunger with a piston at the extreme end coupled to the cylinder, and a circular disk positioned on said plunger so as to permit sliding and moving of said plunger within said cylinder, wherein the cylinder has a longitudinal groove partially penetrating the wall of said cylinder and adjacent said partially penetrating groove a longitudinally extending section of the wall penetrable by a knife, said plunger having flaps extending outwardly of the axis of said plunger, there being a support disk of a semi-rigid piston at the extreme end opposite the circular disk, one of said flaps being oppositely aligned with the weakening groove of the cylinder, there being a recess in said flap immediately adjacent said support disk of said piston, said recess providing a transversely extending housing, there being a compressible spring having one of its ends attached to the wall of said housing and a cutting blade in said housing fixed to the other end of said compressible spring, said cutting blade being guided by a cover of said housing having a slot with a width slightly greater than the thickness of said blade, whereby to prevent twisting of said blade, said cutting blade being positioned so that upon injection of a solution, said weakened groove of the wall is cut along the length thereof as the injection proceeds, said cylinder having guide means for one of said flaps other than one which contains said blade to prevent rotation of the piston rod about its axis.