Pipe coupling

Claim 1

A COUPLING FOR CONNECTING A LATERAL CONDUIT TO THE SIDE OF A MAIN, SAID MAIN HAVING A HOLE FORMED IN THE WALL THEREOF, SAID COUPLING COMPRISING: (1) AN INNER TUBE HAVING AN AXIAL PASSAGE THERETHROUGH AND HAVING AN AXIALLY INWARDLY EXTENDING INNER END PORTION, SAID INNER END PORTION EXTENDING TO AT LEAST THE OUTER SURFACE OF SAID MAIN WHICH DEFINES SAID HOLE, THE RADIUS OF SAID HOLE AND ONE OF THE PERIPHERAL SURFACES OF SAID INNER END PORTION BEING SUBSTANTIALLY THE SAME, (2) AN OUTER TUBE OF LARGER INTERIOR DIAMETER THAN THE EXTERIOR DIAMETER OF SAID INNER TUBE, SAID OUTER TUBE SURROUNDING AND BEING RADIALLY SPACED FROM SAID INNER TUBE, THE AXIALLY OUTER END OF SAID OUTER TUBE BEING ADAPTED TO SEALINGLY RECEIVE SAID LATERAL CONDUIT, (3) WALL MEANS SURROUNDING SAID INNER TUBE AND INTERCONNECTING SAID INNER END PORTION OF SAID INNER TUBE WITH THE RADIALLY ADJACENT PORTION OF SAID OUTER TUBE, SAID WALL MEANS CONNECTING WITH THE INNER END PORTION AT A POINT SPACED AXIALLY OUTWARDLY FROM THE OUTSIDE SURFACE OF SAID MAIN, (4) A LEAST FOUR PERIPHERALLY DISPOSED, SUBSTANTIALLY EQUALLY SPACED LUG MEANS EXTENDING AXIALLY INWARDLY FROM THE AXIALLY INNER SURFACE OF SAID WALL MEANS FOR ENGAGING THE OUTSIDE SURFACE OF SAID WALL MEANS AXIALLY INNER ENDS OF SAID LUG MEANS HAVING A RELATIVELY SMALL AREA COMPARED TO THAT OF SAID WALL MEANS AND DEFINING IN PART A SURFACE WHICH IS PARALLEL TO THE OUTSIDE SURFACE OF SAID MAIN, SAID AXIALLY INNER ENDS OF SAID LUG MEANS BEING THE ONLY SURFACES OF SAID COUPLING IN CONTACT WITH THE OUTSIDE SURFACE OF SAID MAIN, (5) SAID WALL MEANS, SAID INNER END PORTION, AND THE OUTSIDE SURFACE OF SAID MAIN DEFINING AN ANNULAR SPACE, SEALING MATERIAL IN SAID SPACE, THE VOLUME OF SAID SEALING MATERIAL BEING GREATER THAN THE VOLUME OF SAID ANNULAR SPACE, (6) SAID LUG MEANS DEFINING OPENINGS WHICH COMMUNICATE WITH SAID SPACE TO PERMIT THE ESCAPE OF EXCESS SEALING MATERIAL AND THEREBY PROVIDE A VISIBLE INDICATION OF THE MADE-UP JOINT.