Abstract: A truss assembly for reinforcing concrete pipe that includes a mat into which has been woven a series of longitudinally spaced truss bridges that extend across the width of the mat. The mat is cast into a pipe at the points of maximum stress so that the bridges provide circumferentially positioned load carrying sections that are capable of resisting relatively high internal shear and tensile stresses.

Abstract: A flexible gasket for sealing a concrete pipe within a hole formed in a concrete wall. The gasket contains a body ring having sufficient mass to support the gasket within the hole without sagging and a resiliency to allow the gasket to be collapsed inwardly upon itself whereby the gasket is passed easily into and out of the hole. The gasket further contains a finned section mounted inside the ring having circular fins that are disposed inwardly toward the center of the gasket. A series of fins increase in length from the front end of the gasket toward the back end thereof and are adapted to contact the outer surface of a pipe inserted into the gasket opening to compress the gasket in stages against the inside surface of the hole.

Abstract: Apparatus for placing steps in a concrete pipe or riser immediately after the pipe has been cast but before it is cured. A movable carriage is mounted upon a support column that is arranged to move a step driving mechanism vertically along the inner wall of the riser before the riser is removed from the casting jacket. The position of the carriage is automatically indexed to sequentially place the driving mechanism at the desired vertically spaced step locations. The drive mechanism is actuated at each location to drive a bifurcated member horizontally into the wall of the riser. In one embodiment of the invention the bifurcated member is a step that is automatically gravity loaded into the mechanism from an overhead supply magazine. In this embodiment of the invention the step is embedded in the riser and is set in place during curing.

Abstract: This invention relates to a composite flexible seal for providing a fluid tight joint between a pipe section and the inside surface of a receiving opening. The seal includes a slightly elongated tubular body formed of an elastomeric material and a spring-like metal snap ring encapsulated within the body. The ring can be collapsed inwardly upon iself reducing the outside diameter of the body and allowing the seal to be inserted into the receiving opening. Once situated in the opening the ring is expanded causing the seal to be locked in fluid tight contact against the wall of the opening. A pipe section is inserted into the seal opening to complete the joint.