Patent GB-548340-A (GB)
Title: Improvements relating to pre-fabricated portable huts, sheds, houses and the like
IPC: E04B1/26
Filed: 1941-01-21
Abstract: 548,340. Portable buildings. GOMME, E. D. Jan. 21, 1941, Nos. 805, 2495, 3072, 3073 4033 and 5962. [Class 20 (i)] [Also in Group XXIII] A portable building comprising prefabricated panels and spaced supports to which the panels are connected, has the panels constructed doublefaced hollow, curved or flat, on the " stressed skin " principle and so connected to the supports that they form with the supports a rigid unitary structure. By the expression " stressed skin principle " according to the invention is meant a panel comprising a framework of non-metallic strip material to which the facing sheet or sheets is cemented or glued so that the panel when regarded as a beam under load has a common neutral axis for the framework and skin, the skin being operative to take substantially all the bending moment stresses and the strips being spaced apart a distance of not less than 10 inches to allow this. Each panel, which may be of composite form, that is, partly double-faced and partly single-faced, and may be flat or curved, comprises a rectangular framework 5 of wood to which is secured an inner framework of crossing members 6, each formed of slots cemented together, the members being interfitted together at their crossings and cemented if necessary and facing sheets 2 and 3 cemented or glued to the framework members. The facing sheets may be continuous sheets of plywood, or the like, or may be of strip form lying lengthwise of the panel or diagonally, the joints between the strips being free or being tongued and grooved. The panels are arranged with their longer axes in the direction of the length of the building and are fitted together with butt, socket or rabbet joints, the edges of the sheets projecting from the framework to form the joints. The panels as far as possible are made interchangeable but in some cases windows are provided in the panels or the panels may be of different thicknesses as shown in Fig. 30 to form socket joints and in positions such as the bottom rows the interval frame members may be disposed closer together. The transverse supports for the building may be T-section metal bars, hollow beams, lattice trusses, built-up wood strip beams or where partitions are provided, these may serve as the spaced supports to which the panels are connected. The building may be semi-cylindrical in section or of other curved form with axis horizontal or vertical or of gable-shape in which case it may comprise more than one storey. The lattice trusses may be complete with flanges and webs or the panels themselves may constitute the outer flanges of the trusses. Each truss as shown in Fig. 2 is formed of lattice bars 13 formed in triangular fashion with the inner flange bars 12, the bars being joined at their junctions to the inner bars and when no outer flange is provided, they are joined at their outer junctions by outer blocks 15, Fig. 12, filler blocks 17, and bolts 18, and the blocks 15 serve to secure the edges of the panels by bolts 14. Metal cover plates may be fitted over the ioints to stiffen them and filler blocks 20 may be used within the edges of the panels. The ioints may be rendered waterproof by strips of bituminous material 22. The end members 12 of each truss framework may be extended downwardly to form struts to rest on foundation blocks 53 or a separate strut member may be nrovided to which the members 12 are connected. The lower edges of the lowest panels are supported in clips 50, Fig. 7, which clamp them to chocks 47, 48 secured by plates 46 to the truss members 12, so that floor loads and other stresses are not transmitted to the panels but to the trusses. When floors are provided these form with the transverse supports structures similar to three pin arches, the ground serving as the lower member of the arch when no floor is provided. The floor is formed of hollow stressedskin panels 24 which may be joined together at their edges and are carried by hollow beam-like or truss-joists 30, 31 disposed at the joints between the panels ; the ends of the transverse joists are received between plates bolted to the sides of the members 12 and to the ends of the joists. The floor panels may simply rest on supports on the ground or on joists and may not be connected to the main structure but if so connected a bolt and slot connection 107, 108, Fig. 27, is provided so that strains due to inequalities in the ground surface may not be transmitted from the floor to the superstructure. The floor panels may form the flange of the truss when lattice truss joists are used and in multi-storey buildings of gable form, the upper floors are also supported by lattice trusses joined at their ends to the lattices truss supports for the sides and roof. In a modification as shown in Fig. 35 the prefabricated supports for the panels are formed of slots curved to the curvature of one of the flanges of the support and glued together to form a composite member 123, with blocks 124 glued on the sides thereof to which the edges of the panels are bolted. When T-section metal supports are used the web of the support may face inwardly or outwardly. The end closures of the building may be also formed with hollow stressedskin panels joined by butt, socket or rabbet joints rendered waterproof by bituminous strips. These ends are supported on end bearers supported by struts 69, Fig. 3, resting on concrete blocks, the end bearers also supporting the ends of the floor panels. Some of the end panels are formed with windows, and a door which may also be of a stressed skin constructed is provided to close an opening provided in the end closure. A ventilating louvre 67 is also provided above the door. The ends of the roof panels are bolted to the upper edges of the end closures by bolts passing through filling pieces in the abutting panels and the joints are made weatherproof with strips of bituminous felt. Partitions with door spaces therein may be provided transversely and longitudinally of the building and if built of stressed skin panels may replace the supporting trusses in these positions. A table 78 may be provided hinged to the end closure and when turned upwardlv may serve as a shutter for the window. Specifications 548,341 and 548.374 are referred to.