Abstract: A spiral conveyor for a concrete extrusion machine has a first spiral conveyor section with a first external diameter. There is a second spiral conveyor section having a second external diameter which is greater than the first diameter. The second section is spaced apart from the second section. A third spiral conveyor section is between the first section and the second section. The first end of the third section is connected to the first section and the second end is adjacent to the second section. The second spiral conveyor section may be mounted on a hollow shaft of the third section. The second section has two longitudinally divided components, each having a recess therein. Connectors interconnect the two components and a locking device is between the hollow shaft and the second section.

Abstract: A spiral conveyor for a concrete extrusion machine has a first spiral conveyor section with a first external diameter. There is a second spiral conveyor section having a second external diameter which is greater than the first diameter. The second section is spaced apart from the second section. A third spiral conveyor section is between the first section and the second section. The first end of the third section is connected to the first section and the second end is adjacent to the second section. The second spiral conveyor section may be mounted on a hollow shaft of the third section. The second section has two longitudinally divided components, each having a recess therein. Connectors interconnect the two components and a locking device is between the hollow shaft and the second section.

Abstract: A spiral conveyor for a concrete extrusion machine has a first spiral conveyor section with a first external diameter. There is a second spiral conveyor section having a second external diameter which is greater than the first diameter. The second section is spaced apart from the second section. A third spiral conveyor section is between the first section and the second section. The first end of the third section is connected to the first section and the second end is adjacent to the second section. The second spiral conveyor section may be mounted on a hollow shaft of the third section. The second section has two longitudinally divided components, each having a recess therein. Connectors interconnect the two components and a locking device is between the hollow shaft and the second section.

Abstract: A machine for extruding hollow cored concrete sections, wherein concrete forced into a travelling mold by augers and trailing mandrels form a cored concrete slab, wherein the mold is provided with a vibrating top plate assembly having forward and trailing sections, the forward section having a greater amplitude of vibration than the trailing section so as to minimize amplitude to vibration transferred to the concrete in the afterpart of the mold.

Abstract: An extrusion machine for continuously making articles, such as concrete slabs, by forcing the article-forming material through a mold, said machine being moved forwardly by reaction as the material is forced against the portion of the article already formed. The material is moved under pressure by one or more spiral conveyors through the mold, and a forming element of any predetermined cross-sectional shape is substantially aligned with the down-stream end of each spiral conveyor and is mounted so as not to rotate with the latter. It is preferable to provide a vibrator in each forming element.