A resilient gasket having an outer flange positioned within a manhole opening and held by a compression band. The gasket has a central opening with an enlarged beaded periphery to encircle a pipe. A tapered intermediate section is joined to the outer flange and the beaded periphery. The intermediate...http://www.google.com/patents/US4711455?utm_source=gb-gplus-sharePatent US4711455 - Gasket for use in manholes and including clamping band having cooperating projections and grooves for preventing relative axial movement of the opposing ends of the clamping band during installation and for facilitating expansion by an expansion jack
