Tubular coupler with retainer

Claim 1

A coupling formed between two rigid and undeformable coaxial tubular members, one of which tubular members is rigid, undeformable, has a smooth outer surface undergoes an increase in external diameter at a mouth region thereof in the form of a rounded circumferential flange at which it is to be coupled to the other tubular member and is of substantially uniform internal diameter in said mouth region, the coupling comprising a single annular retaining member disposed around said one tubular member along a portion of the length thereof and being formed separately from said one tubular member, the annular retaining member being a one-piece split-ring member of synthetic plastic material having a cylindrical inner surface and having straight cylindrical external threads, said retaining member being formed with a slit extending therethrough along the entire length thereof in a direction parallel to its cylinder axis providing abutting longitudinally extending faces at the slit and being sufficiently elastically deformable to permit its expansion to define an opening sufficiently larger in cross-section than said increased diameter portion of said one tubular member for the retaining member to be fitted around said portion of the length of said one tubular member, the external diameter of said portion of the length of said one tubular member and the internal diameter of said retaining member being matched so that, in the coupling with the retaining member emplaced on said portion of the length of said one tubular member, said faces are in abutment along their entire length creating a continuous ring of said synthetic plastic material in intimate contact with the exterior of said portion of the length of said one tubular member to apply equal pressure around the one tubular member throughout the area of contact, with the internal diameter of said retaining member being smaller than the maximum external diameter of said one tubular member at said mouth region thereof, the retaining member being retained on said one tubular member against withdrawal lengthwise from said one tubular member at said mouth region thereof while retaining said faces thereof in abutment, as a result of the retaining member being in operative screw-threaded engagement with the other of said tubular members and in engagement with said rounded circumferential flange, which coupling additionally comprises a resilient sealing element positioned forwardly of and adjacent to said mouth region, means fixing said sealing element to said other tubular member to provide fluid-tight seal between said tubular members.