Light walled conduit

Claim 1

A light walled circular metallic conduit comprising a first conduit member and a second conduit member identical to said first conduit member, said first conduit member including a first end in the form of an expanded bell section having a constant circular cross section, an end of said second conduit member being nonexpanded and having a constant circular cross section, said end of said second conduit member being snugly received within said first end of said first conduit member in a telescopic relation, an externaly threaded section functionally unitary with said first end of said first conduit member, a nut having adjacent first and second sections and internal threads on said first section matingly engaging said externally threaded section, a radially inwardly directed internal surface on said nut at the junction of said first and second sections, said second section having an end face with curved top and bottom edges, an end surface opposing said radially inwardly directed internal surface of said nut on said externally threaded section of said first conduit member, a split ring of harder material than said second conduit member, said split ring having a central portion flanked by two inclined edge portions, said edge portions diverging in a radially inward direction, said split ring having circumferentially overlapping end portions, each end portion including a notch at one side thereof with the other end portion fitting into said notch, an elastomeric seal encircled by said split ring and surrounding said second conduit member, an annular gap between said second section of said nut and said second conduit member and an annular leakage preventing elastomeric skirt movable with said nut and secured thereto, said skirt including a flange extending radially inwardly constructed and arranged for engagement with said top edge of said end face to orientate said skirt on said nut, said flange spaced from the remainder of said end face to create an annulus therebetween, said flange terminating in a retroverted lip having a gradually deminishing thickness extending into and filling said gap to form a watertight seal whereby as said nut is screwed on to said externally threaded section, said radially inwardly directed internal surface of said nut and said end surface of said threaded section force said split ring to bite into said second conduit member.