Hypodermic syringe

Claim 1

A HYPODERMIC SYRING COMPRISING: A THIN-WALLED THERMOPLASTIC BARREL WITH A FRONT WALL HAVING AN INNER FRUSTO-CONICAL SURFACE SLOPING TOWARD A CENTRAL DISCHARGE OPENING; AND A THERMOPLASTIC STOPPER SUFFICIENTLY RIGID TO CREATE A TRAVELING SEALING-BULGE PROGRESSIVELY ALONG SAID THIN-WALLED BARREL AS THE STOPPER SLIDES ALONG THE BORE OF SAID BARREL, SAID STOPPER HAVING A REAR WALL AND A FRONT WALL RESPECTIVELY BOUNDED BY PERIPHERAL TRAILING AND LEADING EDGES, SAID EDGES HAVING DISPOSED THEREBETWEEN A CONVEXLY CURVED SEALING SURFACE TAPERING REARWARDLY SUBSTANTIALLY FROM SAID LEADING TO SAID TRAILING EDGE, SAID STOPPER HAVING A CENTRALLY LOCATED, FORWARDLY TAPERED NOSE PORTION, SAID BARREL HAVING A DEFORMABLE POCKET WITH AN INTERNAL SURFACE THAT IS PERMANENTLY BULGED OUTWARDLY REGARDLESS OF THE POSITION OF SAID STOPPER IN SAID BARREL BORE, SAID POCKET BEING IMMEDIATELY ADJACENT THE INNER FRUSTOCONICAL BARREL SURFACE AND SUBSTANTIALLY BOUNDING THE REARWARD MARGIN THEREOF, THE LARGEST DIAMETRICAL PORTION OF SAID REARWARDLY TAPERED CONVEX SEALING SURFACE OF SAID STOPPER PROGRESSIVELY BULGING SAID DEFORMABLE POCKET UNTIL THE STOPPER SEATS AT THE REAR MARGIN OF THE INNER FRUSTOCONICAL SURFACE OF SAID BARREL, SAID DEFORMABLE POCKET HAVING AN INNER SURFACE CONFIGURATION COMPLEMENTARY TO THE OUTER PERIPHERY CONFIGURATION OF SAID STOPPER, SAID FORWARDLY TAPERED NOSE PORTION BEING SO CONFORMED IN RELATION TO THE SAID STOPPER LEADING EDGE SO AS TO PERMIT SAID LEADING EDGE TO COMPLETELY MOVE THROUGH SAID POCKET IN SEALED RELATION AND ULTIMATELY SEAT AT THE REAR MARGIN OF SAID FRUSTO-CONICAL BARREL SURFACE.