Abstract: A water inflow impervious manhole cover assembly includes a molded non-metallic frame, an imperforate manhole cover and a fastening mechanism releasably interconnecting the frame and the cover. The frame includes an annular peripheral frame wall defining a cover-receiving seat with a radially inwardly extending lip having a seating surface with an annular sealing channel formed therein. The fastening mechanism includes cams rotatable relative to the frame between a locked position wherein the cams engage the frame and an unlocked position wherein the cams are disengaged from the frame for removal of the cover. An annular watertight seal is formed between a bottom planar surface of the cover and the seating surface of the frame and a gasket retained within the annular sealing channel, when the cams of the fastening mechanism are disposed in the locked position.

Abstract: A water inflow impervious manhole cover assembly includes a molded non-metallic frame, an imperforate manhole cover and a fastening mechanism releasably interconnecting the frame and the cover. The frame includes an annular peripheral frame wall defining a cover-receiving seat with a radially inwardly extending lip having a seating surface with an annular sealing channel formed therein. The fastening mechanism includes cams rotatable relative to the frame between a locked position wherein the cams engage the frame and an unlocked position wherein the cams are disengaged from the frame for removal of the cover. An annular watertight seal is formed between a bottom planar surface of the cover and the seating surface of the frame and a gasket retained within the annular sealing channel, when the cams of the fastening mechanism are disposed in the locked position.

Abstract: 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.

Abstract: A manhole or catch basin assembly comprises separable component parts which assemble to a unitary structure, the component parts being readily replaced or interchanged to increase the vertical height of the assembly such as when a road surface is repaved to an elevated height; the component parts are molded parts which fit snugly together in sealing engagement.