Abstract: A machine for "dry mix" packerhead concrete pipe manufacture has two stations and a separable tubular jacket movable therebetween. A rotatable cylindrical packerhead is movable axially within the jacket and a "dry mix" delivery means deposits mix atop the packerhead as it rotates and moves vertically upwardly within the jacket. The packerhead distributes the mix thereabout to form a concrete pipe in the jacket. A radially expandable and contractable core is movable axially in a contracted condition to a position within the pipe and is then expanded. Vibrators within the core are operated to "redensify" the pipe; that is, to compact the mass thereof, to eliminate voids, and to relieve residual forming stresses therein. A guide ring is employed to align the contracted core axially with the pipe during entry and further guiding and supporting devices for the core are provided. Core entry and withdrawal is power actuated as is core expansion and contraction within the pipe.

Abstract: Precast concrete structural units and composite wall structure comprising a plurality of the units stacked vertically in horizontal rows. Each unit comprises a pair of laterally spaced longitudinally extending side panels. A pair of laterally extending connecting arms are connected to or formed integrally with the panels at their respective inner surfaces whereby to secure the panels in relatively fixed position. A mortise-tendon connection between superposed units is provided with a vertically recessed mortise at the bottom of each connecting arm and a complementary vertically projecting tendon at the top of each arm. Each mortise and tendon defines a pair of laterally spaced oppositely facing generally vertical bearing surfaces and each mortise and tendon is approximately 1/3 the total width of the associated structural unit. Longitudinal spacing of connecting arms from each other is approximately twice the longitudinal spacing of each arm from the adjacent end of the side panels.

Abstract: Apparatus for precasting concrete products wherein dry mix is deposited in casting cavities defined by mating upper and base form sections, vibrated and/or pressure compacted, and the upper form section removed immediately for curing of a free standing green cast product. A single upper form section cooperates with a number of base sections and the latter are used to transport the green cast products for curing. Automatically separable base section parts are also employed for the transport of cured products. Forms are adapted for fork lift handling and include high intensity vibrators, sight openings for ascertaining a cavity full condition, closure plates for fill openings, pressure applying and finishing devices, and sectionalized construction for various size products. Casting machine includes mix delivery apparatus and form handling apparatus for upper and base form sections for automated casting and transfer of green cast products for curing.

Abstract: A method and apparatus for making concrete pipe and, more particularly, for the vibration treatment of concrete pipe for compaction and residual stress relief. A concrete pipe is formed within an external jacket employing a rotary packerhead method wherein the jacket is positioned vertically and the packerhead is moved progressively upwardly within the jacket rotating and distributing mix radially outwardly and troweling the internal surface of pipe under formation. On completion, the green pipe is removed from the pipe making machine and transported to and above a hollow vertically split and radially expandable and contractable cylinder. The pipe is lowered about the cylinder with the latter in a contracted condition, the cylinder is expanded into engagement with the pipe internal surface, and a vibrating means within the cylinder is actuated to vibrate the pipe throughout its length.

Abstract: A method and apparatus for making concrete pipe and, more particularly, for the vibration treatment of concrete pipe for compaction and residual stress relief. A concrete pipe is formed within an external jacket employing a rotary packerhead method wherein the jacket is positioned vertically and the packerhead is moved progressively upwardly within the jacket rotating and distributing mix radially outwardly and troweling the internal surface of pipe under formation. On completion, the green pipe is removed from the pipe making machine and transported to and above a hollow vertically split and radially expandable and contractable cylinder. The pipe is lowered about the cylinder with the latter in a contracted condition, the cylinder is expanded into engagement with the pipe internal surface, and a vibrating means within the cylinder is actuated to vibrate the pipe throughout its length.