Patent attributes
An expansion ring assembly for sealing a gasket with respect to an annular wall of a rigid structure. The expansion ring assembly includes a drive mechanism for engaging and driving apart the opposing ends of an expansion ring to thereby radially expand the ring. The drive mechanism generally includes a pair of block members, formed of steel or a rigid plastic, for example, having oppositely threaded bores therethrough, and a bolt having oppositely threaded ends which are threaded within respective threaded bores of the block members. The block members are interlockingly engaged with respective opposite ends of the expansion ring. Rotation of the bolt in a first direction simultaneously drives the block members apart from one another along the bolt to radially expand the expansion ring, and rotation of the bolt in a an opposite, second direction simultaneously drives the block members toward one another along the bolt to allow the expansion ring to radially contract.