Static structures (e.g. – buildings) – Composite prefabricated panel including adjunctive means – Having separate attached – elongated edging or stiffener
Reexamination Certificate
1998-11-20
2002-06-18
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Composite prefabricated panel including adjunctive means
Having separate attached, elongated edging or stiffener
C052S309120, C052S309140, C052S309170, C052S783100, C052S784100, C052S784150, C052S794100, C428S044000, C428S116000
Reexamination Certificate
active
06405509
ABSTRACT:
TECHNICAL FIELD
The invention concerns panel shaped lightweight structural elements, containing internal reinforcing members, especially for constructing buildings and methods of constructing buildings composed of these elements.
BACKGROUND OF THE INVENTION
At present various kinds of material are used in building construction. Most commonly used are stone, wood, bricks, concrete, metal, plast and similar materials.
Stone buildings are strong and mostly resistant to environmental deterioration, but their principal disadvantages are, that they are a limiting factor in architectural design, that they entail slow progress of construction work, are demanding in material handling efforts, entail costly transport, do not provide a sufficient thermal insulation, etc.
The application of wood as building material opens up more architectural design possibilities, it can easily be used in constructing roofs and floors. The main disadvantages of wood is limited strength, inflammability, shorter service life, limited insulation properties etc.
Brick buildings avoid some of the above mentioned problems. The main disadvantages of bricks are relatively slow progress in construction work, demands on accuracy of workmanship, higher costs in material transport and manipulation, the necessity to provide walls with surface layers etc. Bricks are joined together with mortar (grout), which also covers the gaps between individual bricks and can be used as surface layer of plaster or stucco. Plaster surface (rendering) can be applied to the indoor as well us to the outdoor wall surface. In earlier days brick buildings normally had wooden ceilings and floors, lately concrete has partly replaced wood in these applications.
Concrete—or reinforced concrete—constructions are remarkable for their strength, are sufficiently resilient to external influences, but their heat and sound insulation parameters are rather low, transport is rather demanding, on the building site heavy building mechanisms are unavoidable, up to now the problem of disposal with these buildings after their useful service life has expired, has no satisfactory solution etc. Floors are mostly constructed using beams, external surfaces are treated so as to resist to prevailing climatic conditions, indoor surface are rendered as the customer wishes.
Also, known are some less used kinds of natural materials for building construction: e.g. earth, reeds or rushes, bamboo, straw and similar. The use of these materials is limited to selected territories.
Also known are technologies based on the use of a combination of some of the above mentioned materials. This concerns e.g. wooden or steel basic constructions, where the free spaces are built up with bricks, concrete, wood, glass, plastic or other materials. The central filling may be made of thermo-insulating material, while the external surface layers are of wood, sheet metal, plywood, stucco and other materials. Internal surfaces can be of stucco, various linings, plasterboard etc. During the last decades wooden support structures are mostly being replaced by metal supporting structures, but the basic construction methods have not changed. Floors above ground level are usually of brickwork or of wood.
From the above it can be deduced, that there are two principle classes of building construction technologies: those that are assembled on the construction site of individual construction elements, like stone, wood, bricks etc., and those, which are assembled from prefabricates, transported to the erection site as subassemblies, mostly in the form of various panels.
Prefabricated subassemblies with iron or wooden internal support structures are manufactured in a production factory and transported to the construction site, where the building is assembled either entirely using these prefabricated panels and subassemblies, or partly of subassemblies and partly of components and elements assembled on the construction site.
Panels made of steel reinforced concrete have been widely used in the large scale construction of houses. Panels, with insulating and other surface layers or without them, are used to build complete houses, including floors, ceilings and roofs.
Further are known prefabricated panels using layered elements with a load carrying surface layer. These layered elements as a rule contain load carrying surface layers and between them one or two insulating or other fillers, as for example plywood, honeycomb structures etc. An example of a known arrangement is described in the patent number CA 1,284,571 of the year 1991, filed by Peter Kayne. There is a relatively large number of patents, which are based on this construction. The difference between these patents is in principle only in the materials used, possible in the arrangement or construction of the filler material. Some patents describe also the methods used for the production of these prefabricates, as well as the methods of joining individual layers to each other.
The patent number CA 1,169,625, filed by Jack Slater, concerns the panel itself and the method of building construction using this panel. The panel contains supporting studs of either metal or of wood, between which a polystyrene block is located. These panels can be used for making walls, but also floors. The studs are joined to the fillings by commonly known kinds of glue. The inner surface is usually covered with plaster board and the outer surface with bricks or other claddings. The finishing work on internal and external surfaces is in no way connected to the studs and thus cannot transfer any supporting forces, or forces acting outside the panels, besides their own gravity-related weight.
Another example of the presently known state of the art is to be found in patent CA 2,070,079 filed by Vittorio De Zen. This patent is based on forming hollow profiles of thermoplastic materials, which it is possible to assemble in various ways, possible to fill cavities with suitable material.
An inherent disadvantage of this solution is the high cost of the machinery (tool) needed for the pressing, difficult change of panels produced, more complicated assembly, lower mechanical strength, uneasy surface treatment etc.
In summary it can be said, that building construction using small elements is demanding in time, material, work force, transport etc. Construction based on prefabricated panels will overcome some of these insufficiencies, but are usually demanding on transportation, on-site machinery, qualified personnel etc.
SUMMARY OF THE INVENTION
The above described disadvantages are largely overcome by a lightweight structural element in the shape of a panel, especially for building construction, containing a support structure according to this invention. The lightweight construction element contains at least two supporting rods, which at their end are interconnected by cross-bars, between the supporting rods and the cross bars is a core and/or the surfaces of the supporting rods are interconnected by an adhesive structural skin made from material of thickness between 0.5 and 5 mm, of direct tensile strength from 5 to 35 MPa, tensile strength in bending from 5 to 45 MPa, modulus of elasticity from 2 to 30 GPa, specific density of the matrix material 1 to 2.7 g/cm
3
, the shear bond strength of the junction between the structural skin and the support rods is from 1 to 5 MPa and the compressive strength against pressure of the matrix material is from 10 to 70 MPa.
It is of advantage to make the lightweight structural element of at least two supporting rods of “U” profile, facing each other with their open side, possible of four rods of profile “L”, facing each other with their open side.
It is of advantage, to cover the core and/or the rods with a further layer from 5 to 50 mm thick, of direct tensile strength from 0.1 to 10 MPa, tensile strength in bending from 2 to 15 MPa, modulus of elasticity from 2 to 45 GPa, specific density of the matrix material from 1 to 2.7 g/cm
3
, the shear strength of the junction to the adhesive structural skin is from 0.1 to 5 MPa and the compressive
Burns Doane Swecker & Mathis L.L.P.
Friedman Carl D.
Horton Yvonne M.
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