Month in the Patent Office

In cellular panel or like constructional work wherein sheets of plywood or other material are spaced apart by sinuous web elements outlining the cells and joined at opposite edges to the sheets, perforations are provided in the web elements between their edges to give communications between all the cells, the cells being also vented to the exterior of the structure. In fig. 1, plywood sheets 1, 2 are connected by undular web elements comprising thinner plywood strips 3 bonded together at 4 to form cells 6, the strips having perforations 7 either between or through the bonds 4. Fillets 8 may be provided at the edges of the structure, and are vented by perforations 9; further perforations may be provided in the sheets 1, 2. The cells may be of hexagonal or other form. The web elements may be formed by perforating bundles of strips, or by bundling sheets, perforating the sheets along parallel lines, and cutting the bundled sheets between and parallel to the lines of perforations; the sheets may be bonded together along lines which are staggered in alternate sheets, so that when a bundle of strips is cut off, it may be expanded to form the cellular outline. The construction is applicable to surface construction on aircraft. Specifications 556,620 (Group XXIII), and 625,037 are referred to.