The invention concerns an open-space covering facility containing a covering-organ chiefly made of different canvas sheets unrolling towards each other over at least part of the space to be covered . Suchlike covering facilities are generally known as canvas tents for parties, above terraces or pavements, for example . In order to spread the canvas covering over the open space to be covered, usually the canvas sheet is fixed either on some movable supporting arms, or on some construction built up in the open space . When fixed on the supporting arms, these ones carry the unrolling canvas sheet about while stretching it over the open space to be covered .

An inconvenience of the usually known covering systems is, that all of them are needing similar supporting arms . Most of the struts are heavy and are needing therefore a permanent anchoring, for example in the wall or in the floor . They only can be used, when they are braced either in a wall or, for example in case of feast-tents, on a movable structure which requires much handling for assembling or disassembling . The invention aims at realizing a covering facility which is not depending upon any supporting structure or arms . The characteristic of an open-space covering facility according to the invention is that this covering-organ is made of several elements ordered near each other, which elements get shaped by means of gas blown inside them and become self-supporting as they are stretching out over the open-space, but the gas of which is reducing in the elements as they are withdrawing . When stretching the elements out some gas is blown in them that makes them rigid; in that way they are forming the cover . As here inflatable materials are used the whole construction is light and stable, and no struts are needed to support the canvas sheets spread over .

During their moving backwards the gas escapes from the elements, so that the canvas sheets can be compactly stored or rolled up on a spool . Because here the open-space covering facility is made of self-supporting elements, no visible bearing structure is necessary, so that the sight on the covered

space is kept entirely . As an example, for historical monuments this may lead to a very nice way of covering open spaces . A first form of execution of the open-space covering facility ac- cording to the invention has the charactiristic that it is made of two canvas sheets lying over each other, locally riveted together with gastight sewings on several predetermined distances, which join the two canvas sheets locally together . This produces a simple construction easy to manufacture and besides also a light construction .

A second preferential form of execution of the open-space covering-accommodation according to this invention has the characteristic that the diameter of the elements is increasing in the direction opposite to the way of stretching outwards . Therefore, on the one hand the total couple-force exercised on the fastening point is reduced and, on the other hand, a strong construction is created without any sags .

It is good that the open-space covering facility may be provided with some in- and output-apertures for respectively flowing in or out some compressed gas inside the elements . While blowing in some gas with compression, like fore example compressed air, the elements become beautifully straight- shaped . It is good that almost in parallel with the spool-axle some (double) pressing roller may be fixed pressing against the covering-organ during its said movements . The pressing roller cares for stopping any gas that possibly may escape into the still folded canvas sheets while stretching out the elements, and cares for pressing the gas out of the elements when these are moving backwards .

A third form of execution of the open-space covering- accommodation according to this invention has the characteristic that inside the elements some steel cables are taken along with them . When the elements are stretched and filled with gas, the cables are tightened, which increases the solidity of the construction .

A fourth preferential form of execution of the open-space covering facility according to this invention has the characteristic that this covering-accommodation is composed of

at least two covering-compounds and that at least at one extremity of each of them some means of joining is supplied for connecting these extremities to each other . In that way, when several covering-compounds are provided, it is possible to join them closely together so as to obtain a water-tight cover . It is good that the open-space covering facility may be provided with a storm-proof conductor by which it is protected against storms launching out . A fifth preferential form of execution of the open-space covering facility according to this invention has the characteristic that the covering facility is supplied with a pressure-gauge in order to measure the gas-pressure inside the elements, which pressure- gauge is connec-ted with a steering organ that regulates the flow of the gas blown in depending on the measured pressure . Doing so, the pressure necessary in the elements to insure the stability of the open-space covering facility is always reached . The invention will now be defined more clearly on the hand of the drawing . In the different sketches of the drawing the same figures are given to correspondent elements . In the drawing : sketch 1 gives a view overhead of an example of a covering facility according to the invention stretched over an open space ; sketches 2, 3 and 4 give a view overhead of some further forms of execution of an open-space covering-accommodation according to the invention ; sketch 5 lets see a cross-section in the length of an element of an open-space covering facility ; sketch 6 lets see some more details of an example of an open- space covering facility according to the invention ; sketch 7 lets see a cross-section along the line VII-VH' (sketch 1) of an open-space covering facility according to the inven-tion ; sketch 8 lets see a detail about connecting two covering- compounds to each other according to the invention ; sketch 9 lets see a suction-grip valve for assembling two covering-compounds according to the invention . In the forms of execution drawn in sketch 1 of an open-space covering facility according to the invention the covering-com¬ pounds 1, 2, 3 and 4 are spread over a square open space.

It will be clear that the choice of a sqaure space is only given as an example and that the covering-organs according to the invention may be manufactured depending on other geometrical shapes in order to be covering open spaces with different confi- gurations . The open spaces to be covered may thus be of different sorts, such as for example inside courts, sport-fields, open-air theaters, etc.

In the working-out image in sketch 1 the open-space covering facility is made of four triangular covering-compounds 1, 2, 3, 4.

Still the covering-compounds may have different forms . So sketch 2 lets see the view overhead of a open-space covering- accommodation, wherein the covering-compounds 1 and 3 have a triangular form, while the covering-compounds 2 and 4 are trapeziform . In drawing 3 the covering-organs 1 and 2 have each a triangular form, while the covering-compounds showed in sketch 4 each of the have the form of a circle- segment . Whatever covering-compound here is formed with a number of inflatable elements 8 placed near each other . In the exam¬ ple figured in sketch 1, each covering-organ contains five such elements . So as shown in sketch 7, these inflatable elements are made by laying two canvas sheets 9, 10 over each other and connecting them locally on predefined distances by means of gas-tight sewings 5 . The cross-section along the line VII-Vir (drawing 1) shown in sketch 7, lets see a number of knots 5 and a number of swellings 8 . The knots represent the gas- tight sewings riveting locally the two canvas sheets 9 and 10 gas-tight together, and the swellings 8 illustrate the covering elements, which are created by blowing gas inside the volumes formed by two canvas sheets between two successive sewings . Considering the light weight of the canvas sheets and of the herewith shaped inflatable elements, the open-space covering- accommodation according to the invention is easy to applicate, for example in a gutter 20 (sketch 5), and thus doesn't need any anchoring in the wall or similar . So the covering facility is stretching out from this gutter towards the open space to be covered . In order to add a supplementary support to the covering-compounds, an element of support 12 is brought along the gutter's border 20 .

As it may be seen in sketch 5 the diameter of the elements 8 is increasing in the direction opposite to that one in which they are stretching out . The diameter at the end near to the blowing-in aperture 6 is smaller than the diameter at height of the supporting element 12 . Thus the covering elements show a conical profile . Such a conical profile benefits the construction's stability because near to the gutter 20, on which point most of the bearing-power is concentrated in order to support the covering-organ, also a larger gas-volume is present than at the opposite end, where the bearing-power should be much smaller . Further thanks to the conical profile, the couple-traction on the bearing-point in the gutter is lighter because, the farther one moves from the gutter, the more reduced the gas-volume is and thus also the weight . In order to improve still better the stability of the covering- compounds some steel cabels can be brought in conjointly with the elements . They may be fixed either inside or against the canvas sheets. But they may also be placed cross through the swelling 8 . The sewings with which two canvas sheets are locally connected to each other, should be gas-tight so that the gas blown into the swellings cannot escape through these sewings . The sewings are therefore gas-tightly stitched or glued or welded in a canvas made of synthetic material like PVC for example, polyester or polyamid . These materials are suitable for the purpose as they are supple, easy to fashion, proof against ultra-violet and require little maintenance . As illustrated with dotted lines in the drawings 1 - 4, the sewings 5 are following some lines coupled with the geometric shape of the covering-compound . For blowing gas in and out, for example compressed air, each of the covering-organs is provided with at least one flow-aperture 6 as represented in drawing 5 . The flow-aperture is connected to a compressor (not sketched in this drawing) by means of a tube 13 . A steerable three-way valve 14, as an example, is placed in the tube 13. When blowing the gas inside, the valve is standing in one position and, when sucking it out, the valve is placed in the other position . In rest-time the covering-compound is folded on a roller 11 which is to be moved by an engine 15 . For this purpose

the spool is supplied with a gear-wheel connected with the en¬ gine by means of another gear-wheel 16 . Almost in parallel with the spool-axle 11 a press-roller 19 is fixed . The space located between the spool-axle and the press-roller 19 is cros- sed by the elements . The engine is preferably a pneumatic one, the speed of which is determined by the air-compressor's flow . The press-roller 19 is connected with a press-cylinder 14 . By this way, the press -roller 19, whereas being compressed by the press-cylinder, becomes movable and pres- ses against the canvas sheet tightly .

If one wishes to roof over some place with an open-space covering facility according to the invention, the spool-axle 11 with the covering-compounds draped around and the press- roller 19 are fixed for example in a gutter, which is bordering the space to be covered . It will be clear, that another support can be used instead of the gutter, of course . The compressor and the engine may be placed at choice on any spot closely to the covering-organ, as for example on the soil of the space to be roofed over . When stretching the covering-compounds over the space to be roofed over, on the one hand the spool-axle 11 is set in motion by the engine so as to unroll the canvas sheets . The compressor is started on and the compressed gas is lead through the tube 13 towards the flow-apertures 6 of the elements . While unrolling, the canvas sheet crosses the space between the spool-axle 11 and the press-roller 19 . The press-roller is fixed in such a way that it presses tightly the canvas sheet . The press-roller 19 thus sees to it that no gas should penetrate from the inflating elements out towards the still folded parts of canvas . During the action of unfolding the canvas sheets from the spool-axle 11, more gas is pressed inwards the swellings 8 so that the covering elements take shape and thereby start covering the open space . While unrolling the canvas sheets, the herein supplied steel cables are also winded off . When the canvas sheet is completely unrolled and filled up with gas, the steel cable is tightened and the covering element thus consolidated .

In order to avoid precocious wear of the canvas, a wear-preven¬ ting roller 21 is adapted on the conduct-element 12 . When

stretching out the covering-compound rolls over the wear- preventing roller 21 , whereby the friction on the support 12 is reduced, whereby thus also wearing is reduced . The support 12, together with the roller 21 upon it, not only have a supporting and leading task, but doing so see to prevent precocious wear of the canvas .

Considering the increasing diameter of the elements close to the base, an increasing flow of gas here also becomes necessary . If the gas-supply is not augmented, then a risk exists that the covering-compound should bend downwards during its unrolling. In order to make the adjustment of the gas-flow possible, a pressure-gauge is placed inside the elements, which is connected with a steering organ controlling the flow of the inflated gas . The by the gauge measured pressure is transmit- ted to the steering organ . According to the pressure the steering organ determines which flow of gas should be blown in . For this purpose the steering organ is connected with the pneumatic engine and the steering organ sees to it that the by the engine delivered gas-supply should be augmented as the canvas sheets stretches further out . It will be clear that this is only one possible form of execution and that some alternative solutions exist . Thus it is also possible for example to have the pneumatic engine working on a constant flow and to send the compressed air to the elements by way of a steerable valve . In the last case the steering organ regulates the position of the valve . Another alternative may be, in case of constant flow of gas, to reduce the speed in proportion as the elements are stretching further out . The speed will then, for example, be determined depending on the couple-traction exercised on the spool-axle and the pressure in the elements . It will be clear that also a combination of both alternatives may be possible. When rolling in the canvas sheet on the spool-axle 11, the outlet-aperture 6 is opened in order to let the gas escape . The press-roller sees to pressing out of the elements the remai- ning gas in order to have no more gas present in the folded canvas sheets . As to the gas, by preference compressed air should be used. However, it is possible to use another sort of light gas, as for example helium . If helium is used, the outlet-aperture 6 is connected with a tank, in which the flo- wing-out helium can be stored .

As it has already been mentioned, the open-space covering facility as shown in drawing 1 contains four covering- compounds . These four covering-organs are rolled in on their respective spool-axle . The axles are by preference moved by one and the same pneumatic engine and are connected to each other by means of a gear-wheel system . By preference the gear-wheel system should have helical gear-wheels . But it is also possible to have each covering-compound respectively moved by an individual engine . In order to join the different covering-compounds to each other and thus to consolidate the structure on the whole, some adhesive systems are placed on the borders 7 of the covering- compounds . The binding systems for example may be made of suction-grip valves 24 as shown in the drawings 8 and 9, which suction-grip valves are placed on the profiled edges 7 on the borders of the covering-compound . When two edges of two moving covering-compounds placed near or in front of each other get into touch, the space 25 between these edges is vacuum-sucked up so as to agglomerate the borders of the two covering-compounds to each other .

Another way of binding two covering-compounds together is attaching electrically steerable magnets on their edges . In order to realize the watertightness between the different covering-compounds, their surfaces on the edges are supplied with strips, for example in FVC . These strips are also folded up around the spool-axle and besides are helping to conduct the different covering-organs the one in regard to the other one while rolling out or in . When the covering-organs are spread over the open space to be covered, the layer of compressed air in the beam-shaped elements forms a layer of good insulation, which absorbs all kinds of sounds, as for example those owing to rain or hail . In order to protect the covering-organs against sudden storm- winds, the open-space covering-accommodation is provided with a storm -preventing conductor . This storm-preventing conductor contains a movable arm 23, which is fixed near to the spool-axle 11 and the end at which a press-organ 22 is fastend . This press-organ is formed by a plate, for example, or by a roller . The press-organ is by preference connected to a wind-gauge by the way of a steering unit . The power of the

wind measured by the wind-gauge is transmitted to the steering unit . Depending on the power of the wind measured by the gauge, the storm-preventing conductor will then exert some pressure upon the canvas sheet . So, with a windpower greater than 5 the pressure will be maximal and, if there is no wind, the arm 23 may even be withdrawn.

It will be clear that the invention is not limited to the forms of execution indicated in the drawings and the description, but that more variations within the invention are possible . By compartmentalizing the covering-compound in elements, a supporting structure is no more necessary . The rigidity of a structure is insured by the compartmentation and the com¬ pressed air .