Patent ID: 7055184

Claim:
A closet flange for coupling the base of a toilet to a drain pipe, comprising: a main generally cylindrical body portion dimensioned for connection to the upper end of a drain pipe and having a through bore formed by an inner wall of the cylindrical body portion for communicating with the interior of the drain pipe; an attachment flange portion extending radially outward from an upper end of the cylindrical body portion and configured for connecting to the base of a toilet; a knockout temporarily attached to the inner wall of the cylindrical body portion for sealing the through bore and removable by breaking away a peripheral edge of the knockout at a junction with the inner wall of the cylindrical body portion; and a retainer extending radially inwardly from the inner wall of the cylindrical body portion below the region where the knockout is attached and having an inner diameter smaller than an outer diameter of the knockout to prevent the knockout from falling down and through bore when broken away, the through bore having a diameter below the retainer which is larger than the outer diameter of the knockout.