Abstract: A hollow door panel construction includes a rectangular frame of predetermined thickness assembled from side and end members defining an elongated enclosure. Within the enclosure are corrugated paperboard strips, having a width equal to the predetermined thickness. The strips are variously formed and attached to define a plurality of horizontal cell rows, vertically stacked to fill the framed volume. Each cell row spans the internal width of the frame, and includes a centrally positioned short-walled brace cell straddled on either side by a long-walled lateral cell. To complete the panel construction, thin sheets abut and are secured to the opposite faces of the frame and to the outer edges of the strips.

Abstract: An expandable honeycomb slab constructed from sheet material of corrugated paperboard, for filling load voids within a container carrying articles of freight. A plurality of horizontal cell rows, each containing a central diamond-shaped cell straddled by a pair of square-shaped cells, is stacked in vertical relation. Vertically adjacent corners and apexes of the cells are interconnected so as to allow vertical expansion of the suspended cellular array under its own weight. The vertically aligned, centrally positioned diamond-shaped cells provide vertical support and horizontal rigidity for the array, effectively preventing the honeycomb slab from assuming an hourglass configuration.