초록 ▼

Adjustment risers for use in a manhole or catch basin, between a lower support structure, for example, a concrete riser, and an upper frame assembly, adjacent a surface in which the hole is formed, have a molded body and typically are annular; one or more ribs extend outwardly from a first sealing f

Adjustment risers for use in a manhole or catch basin, between a lower support structure, for example, a concrete riser, and an upper frame assembly, adjacent a surface in which the hole is formed, have a molded body and typically are annular; one or more ribs extend outwardly from a first sealing face and a corresponding one or more grooves are formed in an opposed second sealing face, each groove being in opposed relationship with a rib, whereby the adjustment risers may be matingly stacked to provide a required adjustment riser height for a specified manhole or catch basin.

대표청구항 ▼

[What is claimed is:] [1.]a molded body having an inner peripheral wall and an outer peripheral wall, said inner peripheral wall defining an orifice,first and second, spaced apart, opposed sealing faces extending between said inner and outer peripheral walls,at least one continuous, elongate rib ext

[What is claimed is:] [1.]a molded body having an inner peripheral wall and an outer peripheral wall, said inner peripheral wall defining an orifice,first and second, spaced apart, opposed sealing faces extending between said inner and outer peripheral walls,at least one continuous, elongate rib extending outwardly of said first face and a corresponding number of continuous, elongate grooves in said second face,each at least one rib having a convexly curved outer end, and a vertical height greater than the corresponding vertical depth of a mating groove of a mating riser, each groove having a flat floor and opposed side walls extending from said flat floor,each at least one rib being in opposed relationship with a said groove, and being sealingly matingly received by a corresponding groove in a mating riser having a similar molded body, such that in mating the convexly curved outer end of each rib is deformed into sealing engagement with the flat floor of the mating groove between said opposed side walls of said mating groove.