Flexible expansion pipe joint having radial limiting means

Claim 1

A SUBSTANTIALLY NON-POROUS RUBBER-LIKE POLYURETHANE PIPE LINE EXPANSION JOINT HAVING A BORE EXTENDING LONGITUDINALLY THERETHROUGH, AN EXTERNAL FLANGE AT EACH END THEREOF AND AN EXTERNAL WALL EXTENDING BETWEEN SAID FLANGES, A METAL RING IMBEDDED IN EACH END OF SAID JOINT HAVING ONE EDGE LYING WITHIN SAID FLANGE AND THE OTHER EDGE NEAR THE WALL OF SAID BORE, MEANS FOR ATTACHING SAID JOINT TO A PIPE IN SAID FLANGE AND RING, THAT SURFACE OF EACH FLANGE FACING THE OTHER FLANGE BEING TAPERED WITH THE THICKNESS OF THE FLANGE AT THE POINT WHERE IT MEETS THE SAID EXTERNAL WALL BEING LESS THAN THE THICKNESS AT ITS MAXIMUM DIAMETER, AND A SPIRALLY-WOUND METAL MEMBER DISPOSED TIGHTLY ABOUT SAID EXTERNAL WALL AND SECURED IN PLACE BY SAID TAPERED SURFACES OF THE FLANGES SAID SPIRALLYWOUND MEMBER HAVING A LENGTH WHEN ADJACENT LOOPS THEREOF ENGAGE EACH OTHER GREATER THAN THE DISTANCE BETWEEN THE OUTER RADIAL TAPERED SURFACES OF SAID FLANGES.