Internal plastic coupling

Claim 1

AN INTERNAL COUPLING FOR INTERCONNECTING UNTHREADED CONDUIT SECTIONS FORMED OF A SINGLE PIECE OF RESILIENT PLASTIC MATERIAL COMPRISING A CYLINDRICAL CENTRAL PORTION HAVING A RADIALLY OUTWARDLY EXTENDING ANNULUS PRESENTING RADIAL ABUTMENT SURFACES; AXIALLY EXTENDING END PORTIONS OF GENERALLY CIRCULAR CROSS SECTION AND SUBSTANTIALLY CONSTANT THICKNESS HAVING AXIAL UNDULATIONS, EACH SUCH END PORTION TERMINATING AT ITS DISTAL END IN A DIVERGING PORTION WITH THE MAXIMUM PERIPHERAL DIAMETER THEREOF LESS THAN THE INSIDE DIAMETER OF SAID CONDUIT SECTIONS WITH A DIVERGING CONVERGING SECTION ADJACENT SAID DISTAL PORTION AND INTERMEDIATE SAID DISTAL PORTION AND SAID CENTRAL PORTION PRESENTING A PERIPHERAL RIDGE SURFACE HAVING A MAXIMUM DIAMETER GREATER THAN SAID INSIDE DIAMETER OF SAID CONDUIT SECTION WHEREBY AS SAID CONDUIT SECTIONS ARE RESPECTIVELY EXTENDED OVER SAID END PORTIONS TOWARD ABUTMENT WITH SAID RADIAL SURFACES OF SAID ANNULUS THE DISTAL ENDS FREELY ENTER SAID RESPECTIVE CONDUIT SECTION AND ARE THEREAFTER FORCED RADIALLY OUTWARDLY INTO COMPRESSIVE CONTACT WITH THE INTERIOR SURFACES OF SAID CONDUIT SECTIONS AS SAID RESPECTIVE CONDUIT SECTIONS FORCE SAID DIVERGING CONVERGING PORTIONS RADIALLY INWARDLY AND ANNULAR SERRATIONS FORMED IN SAID PERIPHERAL RIDGE SURFACE.