Method of manufacturing elevated floor panels

Abstract

An elevated floor panel is disclosed in which a lower sheet metal element is formed with a plurality of projections extending from the lower plane of the panel to the upper planar surface. The projections are formed in sequential die drawing operations. In the first die drawing operation, square truncated pyramids of intermediate height are drawn so that the upper surfaces of the intermediate projections provide substantially unworked material. In the second drawing operation, four symmetrically arranged, semispherical projections are drawn from the unworked material at the tops of the preliminary projections. In one embodiment, the tops of the semispherical projections are flattened. In another embodiment, the semispherical projections formed in the second drawing operation are fully curved. In such embodiment, a third operation is performed to produce a flattened extremity. The flattened extremities are welded to an upper sheet member to provide efficient stress transfer between the two sheet metal portions of the panel. By sequentially performing two drawing operations on material which is substantially unworked prior to each drawing operation, it is possible to reliably produce projections of greater depth. The compound projections resulting from the two drawing operations provide a compound beam system which efficiently transfers stress to provide a rigid, strong panel. The cavity between the two members is, in some cases, filled with a lightweight concrete.