Abstract: An inner roller used for roll forming pipe elements has a flange extending radially from a body. The flange has a surface divided into annular surface portions. The surface portions have orientation angles measured relatively to the axis of rotation of the inner roller. The orientation angles of surface portions farther from the body have greater orientation angles than the surface portions nearer to the body to mitigate adverse frictional effects between the pipe element and the flange during roll forming.

Abstract: A roller for engaging an outer surface of a pipe element during roll forming has a perimeter region defined by three faces. A channel is positioned in one of the faces. The channel extends circumferentially around the perimeter region and provides a void space that reduces the contact area between the face and the side surface of a circumferential groove formed in the pipe element during roll forming. The reduced contact area reduces frictional heating of the pipe and roller as well as the tendency of the roller to slip relative to the floor surface of the groove due to axial force engendered when an asymmetrical groove is formed.

Abstract: A roller for engaging an outer surface of a pipe element during roll forming has a perimeter region defined by three faces. A channel is positioned in one of the faces. The channel extends circumferentially around the perimeter region and provides a void space that reduces the contact area between the face and the side surface of a circumferential groove formed in the pipe element during roll forming. The reduced contact area reduces frictional heating of the pipe and roller as well as the tendency of the roller to slip relative to the floor surface of the groove due to axial force engendered when an asymmetrical groove is formed.

Abstract: An inner roller used for roll forming pipe elements has a flange extending radially from a body. The flange has a surface divided into annular surface portions. The surface portions have orientation angles measured relatively to the axis of rotation of the inner roller. The orientation angles of surface portions farther from the body have greater orientation angles than the surface portions nearer to the body to mitigate adverse frictional effects between the pipe element and the flange during roll forming.