Coupling having gasket pocket of varying depth

COUPLING HAVING GASKET POCKET OF VARYING DEPTH A coupling (10) for joining pipe elements in end to end relation, said coupling (10) comprising a plurality of segments (12, 14) joined end to end surrounding a central axis (16) and defining a central space (18) for receiving said pipe elements. At least one of said segments (12, 13) comprising: a pair of projections (28, 30) positioned in spaced apart relation on opposite sides of said one segment (12, 14) and extending toward said central axis (16), at least a portion of each of said projections (28, 30) being engageable with a respective one of said pipe elements, each of said projections (28, 30) having an arcuate surface (32) facing said central axis (16), each of said projections (28, 30) having first and second notches (31) therein respectively positioned at opposite ends thereof, said arcuate surface (32) having a first radius of curvature (34) measured from a first center of curvature (35); a back wall (40) extending between said projections (28, 30), said back wall (40) having an arcuate surface (44) facing said central axis (16), said arcuate surface (44) of said back wall (40) having a second radius of curvature (46) measured from a second center of curvature (48), said second center of curvature (48) being non-coincident with said first center of curvature (35) as measured in a plane perpendicular to said central axis (16).