Patent ID: 7318953

Claim:
A board material comprising: a plurality of flexible sheet members arranged in parallel and spaced from one another at a pitch, said flexible sheet members each having a first surface and a second surface opposite to said first surface; and a plurality of hard strip members, said hard strip members each having two bevelled end edges, said hard strip members including a plurality of long hard strip members and short hard strip members, said long hard strip members being symmetrically bonded in parallel to the first and second surfaces of said flexible sheet members, said short hard strip members being arranged in sets and symmetrically bonded to the first and second surfaces of said flexible sheet members and aligned in line between each two adjacent long hard strip members, said long hard strip members having a length equal to the combined widths of said flexible sheet member plus the gap between each two adjacent flexible sheet members, said short hard strip members each having a width equal to the width of one of said flexible sheet members.