Expansible plug

Claim 1

AN EXPANSION PLUG FOR A SCREW THREADED MEMBER COMPRISING, AN ELONGATED CYLINDRICAL MEMBER HAVING A SHANK AND A RIBBED PORTION AND BEING FORMED OF A RESILIENT DEFORMABLE SUBSTANCE, RIBS ON SAID RIBBED PORTION DEFINING PORT OF THE OUTER SURFACES OF SAID PLUG, AND RELIEFS BETWEEN SAID FIBS, REINFORCING BANDS INTEGRALLY FORMED ON SAID RIBBED PORTION PASSING THROUGH SAID RELIEFS AND DEFINING THE OUTER SURFACE OF SAID PORTION IN REGIONS CIRCUMFERENTIALLY REMOTE FROM SAID RIBS, SAID PLUG DEFINING A BORE THEREIN, AND SLOTS IN SAID RIBBED PORTION EACH EXTENDING LONGITUDINALLY ALONG PART OF THE LENGTH OF SAID ROBBED PORTION AND PASSING FROM THE OUTER SURFACE OF SAID PORTION INTO SAID BORE, SAID SLOTS EXTENDING LONGITUDINALLY BETWEEN ADJACENT BANDS, LEAF SPRING MEMBERS FORMED ON SAID PLUG AND PROJECTING BEYOND SAID OUTER SURFACE OF SAID PLUG, SAID SPRING MEMBERS BEING OF ANGLE CROSS SECTION AND COMPRISING, A FLANGE PORTION EXTENDING IN A DIRECTION RADIALLY AND OUTWARDLY OF SAID PLUG, AND A PLATE PORTION EXTENDING TRANSVERSELY OF SAID FLANGE PORTION IN THE DIRECTION OF ROTATION OF SAID SCREW THREADED MEMBER, SAID FLANGE PROVIDING ENGAGING MEANS ON SAID PLUG FOR ENGAGEMENT OF MATERIAL DEFINING A HOLE FOR RECEIVING SAID PLUG BEFORE SAID PLUG IS EXPANDED BY MEMBER INSERTION INTO SAID BORE, SAID FLANGE BEING TAPERED IN A RADIALLY OUTWARDLY DIRECTION FOR FORMING A SHARP INCISING PART, SAID ENTIRE ANGLE CROSS SECTION INTERSECTING SAID SURFACE OF SAID PLUG AND EACH SPRING MEMBER BEING STIFFENED BY VIRTUE OF SAID ANGLE CROSS SECTION FOR APPLYING RIGID HOLDING PRESSURE AGAINST SAID MATERIAL BY SAID FLANGE WHEN DEFLECTED BY SAID MATERIAL.