Road expansion joint

Claim 1

AN EXPANSION JOINT IN A ROADBED COMPRISING TWO ROADBED SECTIONS SPACED FROM EACH OTHER TO THEREBY DEFINE A GAP THEREBETWEEN, AN ELONGATED ELASTOMERIC BLOCK OF GENERALLY RECTANGULAR CROSS-SECTION HAVING ITS LONGITUDINAL RUNNING EDGES SUPPORTED ON SAID SECTIONS, SAID BLOCK HAVING TOP AND BOTTOM GENERALLY PARALLEL SURFACES, ABUTMENT MEANS MAINTAINING SAID BLOCK ON SAID SECTIONS, THE BOTTOM OF SAID PARALLEL SURFACES BEING THAT SURFACES OF SAID BLOCK PORTIONS WHICH ARE SUPPORTED BY SAID SLABS, SAID BLOCK EXHIBITING A GREATER RESISTANCE TO DEFORMATION FORCES GENERALLY PARALLEL TO SAID SURFACES AND GENERALLY LONGITUDINAL WITH RESPECT TO SAID ROADBED SECTIONS IN THE LOWER HALF OF SAID BLOCK THAN IN THE UPPER HALF OF SAID BLOCK, WHEREBY UPON A LONGITUDINAL MOVEMENT OF SAID ROADBED SECTIONS TOWARDS EACH OTHER, UPWARD BUCKLING CENTRALLY OF SAID ELASTOMERIC BLOCK IS INHIBITED, A STIFFENING ELEMENT, SAID STIFFENING ELEMENT BEING POSITIONED IN SAID BLOCK, SAID STIFFENING ELEMENT POSITIONED BELOW THE MID PORTION OF SAID BLOCK AND BEING OF LESSER WIDTH THAN THE WIDTH OF SAID BLOCK, SAID STIFFENING ELEMENT SPANNING AND OVERLYING SAID GAP BETWEEN SAID ROADBED SECTIONS.