Pipe coupling

Claim 1

A pipe coupling comprising, in combination: two threadedly engageable coupling members (1, 2) one (2) of which is in the form of a body member and the other (1) is in the form of a nut member, including thread means for interengagement between said coupling members, thereby to connect sealingly a pipe section (5) to said body member, the pipe section having an axial passage for conveying a medium therethrough; sealing means (3, 4) between said coupling members and said pipe section, including a first metallic ring (3) interposed between said nut member and said pipe section and a second elastic sealing ring (4) in fluid-tight but resilient engagement with said body member and with said metallic ring; said nut member including an arcuate inner abutment surface (11) as a continuation of its thread means for tight metallic engagement with said metallic ring; the latter having an annular groove (36) for receiving therein said sealing ring; the surfaces of said metallic ring that are immediately adjacent said sealing ring on both sides of said groove providing additional tight metallic engagement with said body member; said metallic ring and said body member having respective axial passages (34, 26) therein substantially contiguous with said axial passage of the pipe section; wherein said metallic ring has a stepped axial bore (32, 33, 34) for receiving therein an end portion of the pipe section, including a first step region (34) with a smaller inner diameter that substantially corresponds to the diameter of said axial passage of the pipe section and a second axially sPaced-apart step region (32) with a larger diameter that at least corresponds to the external diameter of the pipe section; the outer surface (35) of said first region conically tapering to the free end (24) of said body member; annular tooth means (32) on the inner wall portions of said second step region for tight radial engagement with outer wall portions of the pipe section when said nut member is tightened about said body member and said metallic ring; outer wall portions of said second step region being in the form of a frustoconical end portion (31) directed to said arcuate abutment surface of the nut member; and wherein said metallic ring has a radially inwardly drawn circularly shaped abutment surface (33) between said step regions, contiguous with said end portion of the pipe section.