发明名称 Manhole rim and cover assembly
摘要 A manhole rim and cover assembly includes a rim formed with an annular upwardly projecting lip extending around its central opening with a shoulder projecting radially inwardly from the lip at a location spaced below its upper edge. A cover has circumferentially spaced circumferential segments projecting downwardly from its lower surface to fit within the inner side of the lip and to rest upon the shoulder referred to above to prevent crushing of a sealing gasket received between the bottom of the cover and the upper edge of the lip. Vent openings are formed through the lip to vent the manhole when the cover is in place. Spring clips on the cover engage an undercut shoulder on the rim to releasably retain the cover against removal from the rim.
申请公布号 US5201151(A) 申请公布日期 1993.04.13
申请号 US19910775728 申请日期 1991.10.11
申请人 EBW, INC. 发明人 LEBLANC, LEO J.;PHILLIPS, PAUL
分类号 E02D29/12;E02D29/14 主分类号 E02D29/12
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