Corrosion resistant leakproof plastic manhole system
Height adjustment ring for manhole cover frame
Manhole adjusting extension member Patent #: 5956905
ApplicationNo. 088637 filed on 06/02/1998
US Classes:52/19, WITH ENTRANCE FOR PERSONS OR OBJECTS IN HORIZONTAL OR INCLINED COVER52/20, With additional enclosure structure; e.g., manhole52/21, Masonry or concrete52/309.1, WITH SYNTHETIC RESINOUS COMPONENT52/606With traversing passage
ExaminersPrimary: Stephan, Beth A.
Assistant: Glessner, Brian E.
Attorney, Agent or Firm
Foreign Patent References
International ClassE02D 029/12
AbstractA liner for a manhole, inspection chamber or the like comprises one or more sections moulded from synthetic plastics material. The or each section comprises inner and outer skins (2,3) joined together by two series of webs (4,7) extending between and at right angles to the skins (2,3). The webs (4) are disposed at the upper edges (5,6,) of the section and the webs (7) extend between a position below those upper edges (5,6) and a position at its lower end. The upper edges (5,6) and lower periphery (9) of each section are formed so that superposed sections interlock. The arrangement provides an easily installable corrosion resistant load bearing yet light, rigid and deformation resisting structure.