|국가/구분||United States(US) Patent 등록|
|미국특허분류(USC)||404/26 ; 52/21 ; 210/164 ; 404/25|
|발명자 / 주소|
|출원인 / 주소|
|인용정보||피인용 횟수 : 38 인용 특허 : 0|
Plastic extender rings for manholes are produced and are seated on the top ring of a manhole by the use of caulking or other adhesive material. The manhole cover, which is elevated by the plastic ring or rings from the old pavement level to a new pavement level, renders the manhole cover less noisy to traffic and seated more evenly. Recessed or notched portions of the rings receive the asphalt to arrest rotational and upward movement of the rings. Composite adapter rings are provided to adapt an off size manhole top rings, to a standard size manhole cove...
A manhole extension assembly comprising in combination with a manhole cover and a manhole having a top ring embedded in pavement of a plastic extender ring member having a bottom surface mounted in concentric relationship on the upper end portion of said top ring of said manhole below pavement level, said ring member having an upper surface which has an annular recessed seat therein for receiving and seating said manhole cover with its upper level at about the level of said pavement, said ring member having circumferentially spaced peripheral outwardly o...