Patent ID: 7028983

Claim:
A coupling member of a pipe coupling comprising: a cylindrical coupling body, wherein said cylindrical coupling body has a fluid channel and a valve seat formed upon the inside wall of said fluid channel, said fluid channel has an axis, the cross section about said axis is circular, an end opening that is open to the surface of the cylindrical coupling body is provided, and said valve seat is formed from a conical wall surface with its apex pointed toward said end opening; a valve body that is mounted within said fluid channel and that can be displaced along said axis of said fluid channel between a fluid passage closed position and a fluid passage open position, and an urging member that urges said valve body toward said fluid passage closed position, wherein: said valve body comprises: an axis that is collinear with said axis of said fluid channel, a sealing ring that has an outside surface that takes the form of a circle around said axis and, said outside surface being pressed against said conical wall surface which takes the form of said valve seat in said fluid passage closed position, thereby sealing and closing said fluid passage, a sealing ring support that supports said sealing ring, and upon receiving the urging force of said urging member, presses said sealing ring against said conical wall surface, a valve head that has a disk-shaped portion, where said disk-shaped portion is in contact with said sealing ring and holds said sealing ring between said disk-shaped portion and said sealing ring support, and that enters within said end opening of said fluid passage in said fluid passage closed position; and wherein: the angle that the line tangent to said disk-shaped portion and said sealing ring makes with respect to said axis of said valve body is less than or equal to the angle that said conical wall surface of said valve seat makes with respect to said axis of said fluid passage.