Patent ID: 7328493

Claim:
A method of forming a pipe joint, the method comprising the steps of: providing a fluid piping system including at least one as-cast ductile iron pipe fitting, previously cast at a foundry, having a mouth region adjacent an end opening thereof, the mouth region having an annular groove therein, the end opening of the fitting being sized to receive a mating male pipe having an interior surface and an exterior surface; in a post-casting operation, installing a sealing ring within the annular groove provided in the end opening of the as-cast fitting, the sealing ring having an annular gasket body made of a resilient elastomeric material, the annular gasket body having an inner circumferential region and an outer circumferential region, the annular gasket body being installed within the annular groove provided in the mouth region of the as-cast fitting so that the outer circumferential region forms a seal with the fitting mouth region and the inner circumferential region forms a sealing surface for a mating male pipe section; in a further post-casting operation, installing a separate gripping ring within the same annular groove provided in the mouth region of the as-cast fitting, the gripping ring being installed in front of and in contact with the sealing ring, the gripping ring having an inner circumferential surface and an outer circumferential surface and having at least one slit at one circumferential location which creates at least one gap, the gap being defined between two opposing faces of the gripping ring when the ring is in a relaxed state; wherein at least one row of teeth are located on the inner circumferential surface of the gripping ring for engaging selected points on the exterior surface of the mating male pipe; thereafter installing a mating male pipe within the end opening of the mouth region of the as-cast fitting by pushing the male pipe within the end opening, the sealing ring inner circumferential region and gripping ring inner circumferential surface contacting the external surface of the mating male pipe in order to both seal and restrain the mating male pipe and form a secure pipe joint, the sealing ring also contacting and thereby energizing the gripping ring as the mating male pine section moves within the end opening of the mouth region of the fitting.