US Patent 7121593 Triple-expanded mechanical pipe coupling derived from a standard fitting

A coupling for joining pipe segments together is disclosed. The coupling is derived from a standard fitting and has a housing with a socket and a first expanded region adjacent to the socket, a second expanded region adjacent to the first expanded region and a third expanded region adjacent to the second. A sealing member is positioned in the first expanded region, a retainer is positioned in the second expanded region and a support washer having transversely oriented radial and coaxial flanges is positioned adjacent to the retainer in the third expanded region. A lip turned inwardly on the second expanded region overlaps the radial flange and captures the support washer, retainer and sealing member within the coupling. The retainer has a plurality of radial teeth angularly oriented to engage a pipe and prevent its removal from the coupling.