TELESCOPIC MANHOLE AND STORM DRAIN INSTALLATION

摘要

A telescopic manhole or storm drain installation includes a riser assembly provided with an upper section and adjacent lower section the former of which comprises a side wall defining an inverted frustoconical configuration while the latter provides a vertically disposed member having external threads cooperating with a stationary threaded collar. To prepare for resurfacing of a roadway or the like, no excavation about the riser is required prior to its elevation by use of a tool which engages mating receptors located within the interior of the riser. Rotation of the tool rotates the riser assembly within the threads of the collar until the new, elevated plane is achieved. The effort required to displace the riser is minimal due to the movement of its outer surface away from any grouting or roadway base previously abutting the riser. Risers with non-circular upper sections and lids are accommodated by forming the riser of separate upper and lower sections having a sliding joint structure therebetween. Synthetic polymeric materials are proposed for both the risers and lids having a somewhat similar external configuration but employing lids provided with a body of substantial height and formed with a dome-shaped bottom surface such that vertical compressive forces are transmitted radially thereby and conveyed to the surrounding riser side wall.