Patent attributes
A mechanical pipe coupling is formed of segments attached end to end to surround a central space. Each segment has a circumferentially extending cavity facing the central space flanked by arcuate keys which project toward the central space. Two arcuate shoulder surfaces are positioned on each segment. The arcuate shoulder surfaces face the central space and are positioned in spaced relation on opposite sides of the cavity between the cavity and the arcuate keys. The arcuate shoulder surfaces are angularly oriented with respect to an axis perpendicular to a plane containing the segments. The coupling is used to couple pipe elements having a circumferential ring located at the ends of the pipe elements. The angular orientation of the arcuate shoulder surfaces provides flexibility to the joint. A method of joining pipe elements having circumferential rings is also disclosed.