Abstract: A method for joining pipe elements end-to-end using a pair of pipe couplings attached to one another end to end surrounding a central space includes inserting the pipe elements into the central space, moving the coupling segments toward one another and engaging surface regions of the coupling segments with outer surfaces of the pipe elements, initially at a first contact point on the coupling segments and subsequently at second and third contact points on the coupling segments. The first contact point is located between opposite ends of the coupling segments and may be located on a region of infinite radius of curvature, may project radially inwardly toward the pipe elements, and may be located midway between the opposite ends of the segments. The second and third contact points are located at opposite ends of the coupling segments.

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.

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.