Abstract: A coupling for securing pipe elements together in end-to-end relation is disclosed. The coupling has segments joined end-to-end by adjustable connection members. The segments surround a central space which receives the pipe elements. One or more gripping bodies are captured between the segments. The gripping bodies are arranged opposite to each other. The segments have angularly oriented reaction surfaces on the connection members. The gripping bodies have angularly oriented contact surfaces which interface with the reaction surfaces. When the segments are drawn toward each other by the connection members, interaction between the reaction surfaces and the contact surfaces forces the gripping bodies radially inwardly. Inwardly facing arcuate surfaces on the segments and the gripping bodies engage and retain the pipe elements.

Abstract: A concave bearing surface for use with lugs of pipe coupling segments is disclosed. The concave bearing surface is positioned on the lug and surrounds an aperture which receives a fastener attaching the coupling segments together end to end surrounding pipe ends to be joined. Either the nut or the head of the fastener that engages the concave surface may be rotated to tighten the fastener. Engagement between the concave surface and the rotating member reduces the torque required to tighten the fastener and effect a stiff, fluid tight joint. A method of securing pipe ends using coupling segments with concave bearing surfaces is also disclosed.

Abstract: A pipe coupling for joining pipe elements end-to-end is disclosed. The pipe coupling is formed of segments attached to one another circumferentially straddling the pipe elements. The segments are formed from sub-sections connected to one another end-to-end. Each sub-section has a surface region disposed to engage the outer surfaces of the pipe elements. Each surface region has a different radius of curvature from a surface region on a neighboring sub-section. The radii are selected so that when the coupling segments are deformed around the pipe elements, portions of surface regions of selected sub-sections contact the pipe elements, while portions of surface regions of those sub-sections between the selected portions remain in spaced relation away from the pipe elements. A constant and minimal torque is required to bolt the segments together as a result.