Extrusion machine

Abstract

An extrusion machine for making elongated articles of concrete by forcing the concrete through a mold, the article having a relatively large core. The machine is moved forwardly by reaction as the concrete is forced against the molded concrete. A rotatable spiral conveyor extends longitudinally of the mold and moves the concrete through the mold. A nonrotatable forming element in the mold forms the internal cavity. The element is immediately following the downstream end of the conveyor. The forming element has its lower edge positioned so that not more than 10% of the height of the forming element is below the lower edge of the conveyor the lower edge and lower sides of the element being free of any substantial ramp. The longitudinal center line of the element is higher than the center line of the conveyor and includes a ramp extending upwardly from the downstream end of the conveyor. The conveyor forces the concrete over the forming elements to form the concrete article.

Dependencies are inferred from the claim text.