The invention refers to a systems solution for the making of closed surfaces, such as tent-like structures, shelters, furniture, transport equipment, wrapping etc., consisting of flexible, chiefly two- dimentional materials, such as foils, textiles, mats and similar (in the following denoted foils), which are fixed to and interacting with a load-bearing struc¬ ture.

Especially the invention concerns the appli- cation of foils, without reinforcement of the edges, or any other preparation for fixing, which are fixed to and interacting with loadbearing structural units, so that they jointly make out closed, but easily openable and recloseabla surfaces, f. inst for the protection against wind and rain, the containment of bulk materials and liquids, etc

The already known methods which are used, primarily for the purpose of temporary fixing of flexible surfaces to load-bearing structures such as buildings, transport equipment, building components, furniture, packaging etc., can typically be divided into the folllowing four main groups :

The first group comprises systems, typically tent structures, where the complete flexible surface make out one continuous whole, which is taylor-made for completely enveloping the loadbearing structure to which it is fixed intermittantly by means of straps or

similar. Such structures are made to fixed measurements and are thereby in no way satisfying needs of variable shape and size and of arbitrary possibilities of opening through the covering surface. The other group comprises systems, with which typically there occur a number of separate, flexible surfaces in the form of rectangular tarpaulins or similar, each one of which is furnished wit perfo¬ rations for the placing of straps or similar for fixing to the load-bearing structure. Such structures may be given a variety of shapes and sizes through the use of standard materials and structural units, but the fixing by means of straps does not result in total closure, for instance against wind, and also the process is time consuming and makes difficult the opening at arbitrary locations in the covering.

The third group comprises systems, in which there exist a multitude of flexible surfaces, along the edges of which they are furnished with a special profiling and reinforcement, or at the least along two opposing edges, for the attachment to a corresponding profiling of or fixed to the load-bearing structure. Such structures presuppose in general the introduction of the profiled edges of the flexible material from one end, which typically imply that the structures are made in fixed measures and without offering the possibility of arbitrary opening through the covering surface.

The fourth group comprises systems of which the flexible surfaces without any special preparation of these may be fixed by some sort of gripping arrangement to profiled sections, which are fixed to the load- bearing structure. Such systems are known as being applied for fixing textiles on walls, σfr. Publ.Nr. 23 06 749 of the Federal Republic of Germany. However, the method described is not applicable for stretching foils between opposite sides, since a stretching from the "front" side of the foil is not possible, and also it presupposes that the foil, before fixing, is wrapped around a grip list, a fact which makes this solution irrelevant in connection with general enveloping purposes. It is the purpose of this invention to present a system, as indicated in the introduction, which in a simple way is offering very great flexibility - both in the drawing op (design) and erection of the individual structure - and according to needs to satisfy the demand for multiple possibilities of openings in any structure. The system of covering according to thi3 invention is special by the fact, that flexible, primarily two-dimensional materials, such as foils, textiles and mats are inter-acting with loadbearing structures for taking up great loads such as wind of hurricane strength, through the arrangement that the structural units are furnished with recesses of a

moderate depth (2 - 15 mm) to which the materials concerned without any special shaping or any other form of preparation are fixed by means of lists or strips, the strength and shape of which are not critical to the functioning of the joint.

By appropriate design of the structural units and placing of recesses in these it is possible according to this invention to create structural units and composite structures with a very favourable weight/strength ratio, and likewise the design makes possible the mounting of coverings with two or more layers of foils, with an air space in between, for instance for insulating purposes.

In the following the invention will be explained into more details while refering to the drawing in which fig 1 is showing an example of a cross section of a recess according to the invention, fig 2 is showing a cross section of a recess, similar to the one in fig 1, with a foil fixed to it. fig 3 is showing a cross section of a recess similar to the one shown in fig 1 with an altenative way of fixing the foil compared to the fixing shown in fig 2. fig 4 is showing a cross section of a recess, similar to the one shown in fig 1, with the foil fixed to a sliding section placed in the recess, fig 5 is showing an example of a cross section

of an extruded section with recesses for the fixing of foils in several plans. fig 6 is showing an example of a rolled section made from sheet metal with recesses for fixing foils in several plans. fig 7 is showing a side projection of a girder unit with possibilities of fixing in several plans, fig 8 is showing an end projection of girder unit shown in fig 7. On the drawing the recesses are denoted (1).

Fig 1 is showing an example of the design of a cross section of recess (1 ) , which is typpiσally furnished with a protruding lip (1a) in that side from which the foil is entending, and it is furnished with a smaller protruding bead (1b) in the side opposite (1a). The interior width (B) of the recess is at least 2,5 times - and a maximum of 10 times - the depth (H) of the recess, where (H) is a minimum of 2 mm and a maximum of 15 mm.

In fig 2 is shown a cross section of a recess, as in fig 1, with fixed foil (2), which can typically be extended in the directions (S), (V) and (N) from the recess (1 ) , and which is introduced into the recess by means of the squeezer (3), by first guiding the end (3v) in and under the lip (1a) and thereafter pressing the end of (3ø) down passed the bead (1b).

By pulling the foil passed the lip (1a) from one of the directions (S) to (N) the foil is squeezed

between the end (3v) of the squeezer and the lower side of the lip (1a) as well as between the end (3ø) of the squeezer and the rear side (1c) of the recess. In this simple way can be made an excellent locking without the need of a specially high coefficient of friction between the two surfaces. As squeezer mey be used a list or strip of wood, cardboard, plastics etc. with an approximately rectangular cross section. or instance it is possible to use as squeezer a strip of ordinary corrugated cardboard, and without establishing friction by any other means that as herein described, and yet create a locking force using glassfiber reinforced polyethylen foil, which exeeds considerably 1500 kp per meter connection. In practice the squeezer can be made with advantage from an extruded, elastic polymer, for instance with a rectangular section. However, as squeezers can also be used separate pieces of widely differing materials, which are placed at a distance apart according to requirements. As a further example of a squeezer can be mentioned a spring, which squeezes the foil towards the recesses (1d) and (1σ).

With the method of fixing of the foil (2) as shown in fig. 2, the foil may be released from the fixing through a modest pull in the edge (2a) of the foil, whereby the end (3ø) of the squeezer will be pulled passed the bead (1b).

For a more permanent fixing, or in order to secure that immediate release is not possible, the edge (2a) of the foil may be brought around the end (3v) of the squeezer, as shown in fig 3. Thereby is is achieved, partly that the release cannot be made without a special tool, which can reach in between (1σ) and (3ø) in order to lift the latter passed (1b), partly that an extra squeezing is taking place in the recess owing to the additional material introduced into it. In fig 4 is shown in which way the same recess, as shown in f g 1, 2 and 3 can be used for fixing a sliding section (4) to which the foil is fixed at (5).

Fig 5 is showing an example of a section of an extruded structural unit (6) (for instance in aluminum or polymer), which may function as a column, beam' or arch, and which, containing 6 recesses, can be the fixing line for two parallel foils (for instance for insulating purposes) to each of the sides (N) , (0), (S) and (V). Typical placement of foils is shown in dotted lines.

Fig 6 is showing an example of a cross section of a structural unit which can be used a a column, beam or arch, and which can typically be made from rolled sheet metal (8) and (9), which may be joined through arch-welding in line a-a to form a structural unit, which is most attractive because of the very materials saving design. It has in all four recesses ( 1 ) for

fixing of up to two layers of foils, which may be placed in the plans indicated with dotted lines.

Fig 7 is showing an example of a girder unit (10) in which the two main components are identical with the structural unit (7) shown in fig 6, and in which they are joined througt bolted or welded web members (11). The girder unit, which can make up part of a larger frame or arch structure, make possible the fixing of foils in recesses (1 ) in up to four planes perpendi- cular to the main plan of the girder, and at least two planes parallel to the main plane of the girder unit.

Fig 8 is showing an end view (b-b) of the guirder unit (10) shown in fig 7..

Purlins and horizontal stiffening beams and girders in roofs, facades and gables etc. can likewise be made with as an example structural unit (7) as the basic unit.