Patent GB-1208869-A (GB)
Title: Lightweight cellular structure
Inventor: MAISTRE MICHEL ANTOINE JULES
IPC: B31D3/00
Filed: 1967-08-25
Abstract: 1,208,869. Laminated cellular structures; moulding sheet material. M. A. J. MAISTRE. 25 Aug., 1967 [26 Aug., 1966], No. 39315/67. Headings B5A and B5N. [Also in Division D1] A three-dimensional structure comprises at least two identical generally sheet-like members joined together to form a plurality of cells having substantially planar faces, the faces lying in at least three intersecting sets of parallel equidistant planes, and the sets being such that there is no line along which two planes from a pair of sets intersect which is parallel to a line along which two planes from a different pair of sets intersect, and the faces in each plane being contiguous to define continuous planes of the material of the structure, the continuous planes having no gaps. The structure may be formed by providing the members with recesses or peaks, e.g. of half-parallelepipedal form, Fig. 2, or pyramidal form (Figs. 3-7), and then securing the pre-shaped members together to define juxtaposed parallelepipedal, tetrahedral or octahedral cells therebetween. Alternatively, adjacent members in a stack of substantially flat sheet-like members may be secured together by quilting patterns, e.g. of square or hexagonal form, Figs. 21-23, 38, and then the stack may be expanded either by pulling opposite ends of the stack mechanically or by gas or vapour evolved as a synthetic thermosetting resin, impregnating the stack, hardens. The members may be of plastics materials, ductile metal, or fabrics of either organic or mineral, natural or synthetic fibres, e.g. a small mesh wire netting. In the first method of forming the structure, the members may be preformed with their peaks or recesses by a moulding process. A sheet 40, Fig. 11, is impaled on points 49 of spaced, square-based pyramids 48. On closing a linkage 50, the pyramids move into abutting relationship, Fig. 13, and the sheet 40 sags between adjacent points 49 to approximately conform to the pyramidal shape. A plate 51 prevents sheet 40 from rising instead of sagging. Plate 51 is now replaced by a die (52, Fig. 14) complementary to the abutting pyramids to complete the shaping. During or after moulding, the sheet 40 may be hardened by the setting of an impregnated thermosetting resin (in which case the dies are heated) or impregnated plaster, cement, glass, thermoplastic material or low melting-point metal. Instead of pyramids 48 connected by linkage 50, normal male and female dies (58, 59, Fig. 19) may be used, in which case the sheet may be subjected to a preliminary shaping treatment (Figs. 15-18) before insertion between the dies. Alternatively, two rollers (61, Fig. 20) formed with pyramidal peaks and recesses, respectively, may be used in the moulding process. Abutting corners of adjacent members to be secured together may be chamfered to increase the areas joined. In the second method of forming the structure, adjacent fabric layers are connected by stitching, along the quilting lines or by simultaneously weaving superposed fabric layers connected along the quilting lines during the actual weaving process (Figs. 29,-31). Alternatively, the stack may consist of plastics or ductile metal layers and the quilting line connections may be glued or soldered.