COUPLING WITH CONCAVE BEARING SURFACE

摘要

A concave bearing surface for use with lugs of pipe coupling segments is disclosed. The concave bearing surface is positioned on the lug and surround s an aperture which receives a fastener attaching the coupling segments toge ther end to end surrounding pipe ends to be joined. Either the nut or the he ad of the fastener that engages the concave surface may be rotated to tighte n the fastener. Engagement between the concave surface and the rotating memb er reduces the torque required to tighten the fastener and effect a stiff, f luid tight joint. A method of securing pipe ends using coupling segments wit h concave bearing surfaces is also disclosed.