|국가/구분||United States(US) Patent 등록|
|미국특허분류(USC)||404/025; 052/020; 277/012; 277/207.A|
|발명자 / 주소|
|출원인 / 주소|
|대리인 / 주소||
|인용정보||피인용 횟수 : 28 인용 특허 : 6|
A hollow cylindrical-shaped, hat-like sleeve is water-tightly joined with the upper end of the riser section of a manhole structure. The free end of the sleeve is trimmed so that its upper edge fits beneath the shoulder of the frame supporting the manhole cover to prevent subsurface water from entering into the manhole interior through the regions between the manhole cover supporting frame and the top of the riser section, which is usually fitted with adjustment rings to bring the manhole cover frame up to grade. The sleeve is easily cut to any height to...
1. Apparatus for providing a water-tight seal in the region above the riser section of a manhole structure comprising: plastic sleeve means having an integral flange centrally located upon the top of said riser section, said flange extending over at least a portion of the top surface of the riser section, the outer diameter of the riser section being greater than the outer diameter of the flange; a manhole cover support frame with an integral annular upper flange for supporting a manhole cover and an integral lower supporting flange; at least one gr...