Manhole cover, has plastic extension pipe heat welded to journals which are connected to flange protruding from underside of frame around manhole opening

摘要

A frame defines a manhole opening with a length symmetry axis extending through the center of this opening and a flange with a cylindrical wall protrudes from the underside of the frame in the length direction concentric to this symmetry axis. An extension pipe extends concentric to the flange and is connected to the latter via journals which extend radially into the flange from the pipe wall and are mounted in corresponding holes in the flange. The pipe and journals are made from heat-weldable plastic and the journals are heat-welded to the pipe.