Mold assembly for installing a gasket in the peripheral wall of an opening in a wall

A mold assembly for casting a concrete wall having an opening and for anchoring a flexible resilient ring-like gasket in the peripheral wall of said opening to make a seal with a pipe passing through ssid opening, said gasket having an inner pipe-engaging portion and an outer anchoring portion, said assembly comprising:

• (a) a pair of spaced form walls for receiving unset concrete therebetween;
• (b) a flexible, resilient annular mold having opposite end surfaces, an outer surface and an inner cylindrical surface, said annular mold extending between said form walls and having a length such that its end surfaces are in respectively-sealing contact with the inner surfaces of said form walls, said outer surface having a continuous annular groove intermediate said end surfaces of a depth and shape to receive and fit the pipe-engaging portion of said gasket while the outer anchoring portion of said gasket protrudes outwardly from said outer surface and is exposed in the space between said form walls;
• (c) a rigid cylindrical mold-supporting member removably inserted within said annular mold having a length coextensive with that of said annular mold and having an outer surface in contact with the inner surface of said annular mold to support the latter while concrete is cast about the annular mold, about said outer anchoring portion and between said form walls;
• and
• (d) means for removably securing mold-supporting member to at least one of said form walls, whereby once the concrete is cured and the form walls removed, said mold-supporting member can be axially withdrawn from said annular mold and the latter withdrawn from the opening and from the gasket by inwardly flexing said annular mold, while the anchoring portion of said gasket remains anchored in the cured concrete.