Liner
Patent 6195944 Issued on March 6, 2001. Estimated Expiration Date: 
June 2, 2018. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 2, 2018. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3478482 Manhole construction Manhole cover Corrosion resistant leakproof plastic manhole system Height adjustment ring for manhole cover frame Manhole adjusting extension member Patent #: 5956905 InventorAssigneeApplicationNo. 088637 filed on 06/02/1998US 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 passageExaminersPrimary: Stephan, Beth A.Assistant: Glessner, Brian E. Attorney, Agent or FirmForeign Patent References
International ClassE02D 029/12AbstractA 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. | |
