Patent ID: 7401998
Filing Date: 2008-07-22
Classification: E02D

Abstract:
1. In a manhole assembly having a longitudinally upper frame portion disposed on a longitudinally lower cone portion, an improved structure for substantially preventing inflow of water or other material between the upper frame portion and the lower cone portion, the improvement comprising: a plurality of continuous and compressible polymeric foam construction grade rings serially stacked longitudinally and laterally aligned with one another between the upper frame portion and the lower cone portion, one of said grade rings being sealingly secured to the frame portion and another of said grade rings being sealingly secured to the cone portion, a longitudinally adjacent pair of said grade rings having generally flat sides longitudinally confronting one another; wherein said generally flat side of one of said longitudinally adjacent pair of said grade rings is formed having at least a pair of laterally spaced concentric annular grooves and wherein said generally flat side of an other of said longitudinally adjacent pair of grade rings is formed having a male portion corresponding in size and shape to a respective one of said laterally spaced concentric annular grooves, wherein said respective male portion of said other of said longitudinally adjacent pairs of said grade rings is coupled within a respective one of said pair of laterally spaced annular grooves of said one of said longitudinally adjacent pair of said grade rings; and wherein at least one of said plurality of continuous and compressible continuous polymeric foam construction grade rings comprises: