FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a device in a joint between two sheet-like building elements made for insulating purposes.

Such building elements may be used for insulating a building or parts thereof against for instance moisture or radon and so as to reduce the heat exchange between the interior of the building and the surroundings. The present invention generally relates to all conceivable uses of building elements for insulating purposes and in particular those for protecting the foundation of a building against moisture and radon gas from the sur¬ rounding ground, for which reason the latter case will be discussed hereinafter in exemplifying but not limiting way.

When insulating the foundation of buildings it was hitherto proceeded in the way that insulating sheets were laid loose close to each other in sev¬ eral layers before the foundation plate of the building was casted or moulded thereupon or close to each other in the mould for moulding basement walls or under the floor structure or on the basement wall of buildings already existing. The disadvantage of these procedures is that a joint between the adjacent building elements does not become com¬ pletely tight, but the elements will slide slightly apart at at least some lo¬ cations. It is even sufficient with very small gaps, which may appear when elements are actually bearing against each other as a consequence of small irregularities in their bearing surfaces, for letting moisture and radon gas find a way through the insulation and reach the interior of the building with a risk of moisture damages on the floor covering or the wall

covering and the formation of mould and radon daughters detrimental to the health. The latters are particularly "nasty", since the radioactive radia¬ tion emitted therefrom has turned out to be strongly likely to cause lung cancer.

BRIEF DESCRIPTION OF THE INVENTION

The object of the present invention is to provide a device of the type de¬ fined in the introduction, which to a great extent reduces the disadvan- tages mentioned above and the inconveniences appearing at the level of the joints between building elements of the type in question.

This object is according to the invention obtained by a device according the appended claim 1. Thanks to the construction of the element portions of both elements extending along the joint border as engagement means fitting into each other and that they are adapted to be introduced into each other, a tight connection between the two adjacent building ele¬ ments may be achieved at the joint, so that this joint does not constitute any place in which moisture, radon gas or the like may come through the insulation in an easier way than by choosing a way through the very ele¬ ments.

It is a matter of course that the device according to the invention also re¬ sults in advantages in heat insulation, since it is precluded that an in- creased flow of heat away takes place at the joint, and a heat insulation having such joints may be especially suitable in an internal supplemen¬ tary insulating of a house built by blue light-concrete, since this material emits unacceptable amounts of radon gas.

At least the surfaces of both elements adapted to form the joint therebe¬ tween as well as the sheet plane surfaces located on one side of the elements are according to a preferred embodiment of the invention cov¬ ered by aluminium foil for reflecting especially radon gas. A joint having an even better possibility to keep the harmful radon gas outside the building is by that obtained.

A second object of the present invention is to provide a building element for insulating purposes, which reduces the risks of letting radon gas passing therethrough and into a building, and this object is according to the invention obtained by providing a building element having a sheet-like body with one or more air channels extending between the sheet planes therealong and means for connecting the air channels to means for gen¬ erating a negative air pressure therein so as to conduct substances, such as radon gas, entering into the element away therethrough and prevent them from passing through the element. By designing a building element for insulating purposes in this way especially radon gas, but also mois¬ ture and undesired substances which despite all manage to penetrate into the building element, may be sucked away before they reach the other side of the element and they are preferably emitted to the ambient atmosphere.

A further object of the invention is to provide a building element for insu¬ lating purposes, a method for production thereof as well as a device for carrying out said method for producing a building element being particu¬ larly suited to insulate buildings against radon gas.

This object is in accordance with the invention obtained by providing a building element having a body of insulating material with small alu¬ minium foil pieces distributed therein as well as a method and a device for producing such a building element according to the appended claims directed thereto. It has turned out that such a building element is very ef¬ ficient in reflecting radon gas, this ability is not reduced with increasing age of the building element and such a building element may be easily handled without any risk of appearance of damages deteriorating this ability, since the aluminium foil pieces of crucial importance for this ability are embedded in the body of insulating material.

Further advantages and advantageous characteristics of the invention appear from the following description and the other dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a specific de¬ scription of preferred embodiments of the invention cited as examples.

In the drawings:

Fig 1 is a perspective view of building elements designed to obtain a de¬ vice in a joint in accordance with a preferred embodiment of the inven- tion,

Fig 2 is a sideview of a device in a joint between two building elements according to a preferred embodiment of the invention with the elements in a not jointly interconnected position,

Fig 3 is a view corresponding to Fig 2 with the elements in a jointly inter¬ connected position,

Fig 4 is a simplified perspective view illustrating a device for producing a building element for insulating purposes according to a preferred em¬ bodiment of the invention,

Fig 5 is an enlarged section view of a part of a building element produced by the device according to Fig 4, and

Fig 6 and 7 are views corresponding to Fig 2 and 3, respectively, of two building elements jointly interconnected and having another construction according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Some sheet-like building elements 1 for insulating purposes and having a device in a joint according to the present invention are shown in Fig 1. It appears that the definition sheet-like is to be interpreted in its broadest meaning, i.e. it does only state that it is a question of an element having two opposite surfaces being substantially parallel to each other, so called

sheet plane surfaces. The elements consist preferably of moulded foamed plastic, which has a very low density and a good heat insulating capacity.

The building elements are made in one piece and have a rebat-like con¬ figuration 2 along the borders intended to be jointly connected to other similar building elements, said configuration having a rib 4 extending along said border and having its free upper end surfaces 3 directed sub¬ stantially perpendicularly to the sheet planes and a groove 5 extending parallelly thereto and delimited by the rib on one side.

Reference is now also made to Fig 2 and 3. The lateral walls 6 of the rib 4 converge in the direction towards the free end surfaces 3 thereof, and the lateral walls 7 of the groove 5 diverge from the bottom 8 of the groove by a degree of divergence substantially corresponding to the degree of convergence of the rib 4. Furthermore, the width of the bottom of the groove 5, the thickness of the rib as well as the height of the rib as seen from the bottom of the groove are so dimensioned, that a rib and a groove identically dimensioned of another building element may be brought into engagement therewith while introducing the respective rib into the respective groove until reaching a position in which substantially the entire surfaces of the lateral wall portions of the ribs introduced into the grooves bear against lateral wall portions of the respective groove. Furthermore, the height of these dimensions are so chosen that the end surfaces 3 of the rib 4 are located at a certain distance from the bottom of the groove 5 in said position. Since the building elements are made of foamed plastic, which may be slightly deformed, the respective rib may after reaching said position be pressed in a little bit further into the re¬ spective groove while deforming the ribs and adjacent element portions, so that a tightening wedge action is obtained in said joint by the fact that it stores potential energy pressing the surfaces of the ribs and the grooves bearing against each other tightly against each other. The sheet plane surfaces on either side of the joint are intended to be located in substantially the same plane after this further pressing inwardly.

Thus, the joining of the two elements 1 , 1 " takes place by moving the re¬ bat-like configurations 2 thereof into engagement with each other by a

relative movement thereof substantially perpendicularly to their sheet planes from the position according to Fig 2 to that according to Fig 3. Fur¬ thermore, the two elements 1 , 1 ' shown in Fig 2 and 3 are covered by aluminium foil 9 on the sheet plane surfaces located on one side, said foil continuing over the rib and groove in question to the opposite sheet plane surfaces. Since the aluminium foil is comparatively sensitive and may easily be torn apart, it is preferably covered by a diffusion tight plastic paste so as to obtain a higher mechanical strength. The definition that the surfaces are covered by aluminium foil made in the claims is intended to comprise the case that this aluminium foil has a coating, so that the alu¬ minium foil in the practice does not constitute the very surface layer of said surfaces. In this way it is obtained in the position according to Fig 3 that the two insulating elements in the region of the joint therebetween function as if they were one single continuous insulating element having one side covered by aluminium foil, while there is also aluminium foil ab¬ sorbing and reflecting moisture, radon gas and the like which with a low probability will enter into said joint.

By arranging the two element 1 , 1' to overlap each other by their rebat configurations in the direction perpendicular to the sheet plane of the elements, so that the joint line 10 between the elements on one side thereof is displaced with respect to the joint line 1 1 on the other side, a higher protection against penetration of such undesired substances in the very joint is obtained.

It is shown in Fig 1 how the rebat-like configuration 2 is arranged on some of the sides of the insulating elements, which however only is made for the sake of simplicity, and it would in the practice be most advanta¬ geous to arrange the rebat-like configuration around the entire building elements, and it would then be possible to cut off that building element which will be located outermost in carrying out the insulating. The rebat configuration on the opposite sides of one and the same building element are then preferably directed with the ribs and the groove bottoms in the opposite directions with respect to each other, so that the insulation may be assembled by applying an element for instance on a wall surface, in¬ troducing a rib of an adjacent element into a groove of the first element, than introducing a rib of a third element into a groove of the second eie-

ment and so on by relative movements of the elements with respect to each other substantially in the direction perpendicular to said wall. It is shown in Fig 1 how two building elements 1 , 1 ' designed for a joint inter¬ connection have a rib 4" and a groove 5" each also along an end border 31 extending substantially perpendicularly to the joint border. A material saving 32 substantially corresponding to the total width of the rib and the groove in the two dimensions of the sheet planes is carried out in the re¬ gion in which the joint border and the end border meet in the one element 1 , while the rib 4" and the groove 5" of the end border of the other ele- ment 1 ' continue to the joint border. It is in this way achieved that a rela¬ tive displacement of the two elements 1 , 1 ' along the joint border in the form of a displacement of said one element 1 towards said end border of the other element 1 ' may only take place until the joint rib 4 of the ele¬ ment 1 comes to bear by means the front surface 33 thereof against the end rib 4" of the other element 1 '. This feature facilitates a process for assembling the elements. Typical dimensions of standardized such ele¬ ments may be: width 600 mm, length 1200 mm and thickness 50 mm.

A device for producing a building element for insulating purposes is shown in Fig 4 and has a body of insulating material with small aluminium foil pieces embedded and distributed therein and in particular arranged to reflect radon gas. The device is very schematically shown and parts thereof have been omitted for the sake of clearness. The device has an aluminium foil roller 12 rotatably and removably journalled in a stand not shown as well as means not shown for unwinding an aluminium foil web 13 from the roller 12. A cutting roll 14 having circular blades 15 closely arranged is rotatably arranged downstream of the aluminium foil roller 12. A counter roll not shown is rotatably arranged on the opposite side of the web 13 with respect "to the cutting roll 14, said counter roll preferably constituting said means for causing unwinding of the web 13 from the roller 12. The cutting roll 14 is arranged to press the web 13 against the counter roll by the blades 15 thereof while at the same time cutting up the aluminium foil web 13 passing in the longitudinal direction thereof into strips 16. A cutting means in the form of a cutting roller 18 provided with longitudinal cutting edges is rotatably arranged downstream of the cutting roll 14 so as to during the feeding of the strips 16 gradually cutting them off near their free ends for forming small aluminium pieces, which fall

down into a collecting hopper 19 arranged under the cutting zone. Any type of dolly or counter means is suitably located in front of the cutting roller 18 for making the cutting function possible.

The collecting hopper 19 emerges through a lower opening into a tube 20 substantially vertically directed and containing a mixer 21 , such as a blade wheel or the like, schematically indicated by dashed lines. Liquid foamed plastic mass and hardener are supplied through two conduits 22 and 23, respectively, to the mixing zone of the tube 20 and are there by the mixer 21 mixed up with the aluminium foil pieces into a substantially uniform mass, which at the lower end 24 of the tube 20 is preferably con¬ tinuously delivered to a mould 30 designed in accordance with the struc¬ ture of a building element, in which the mixture is intended to solidify by the influence of the hardener for forming a building element 1. It is sche- matically shown in Fig 5 how the small aluminium pieces are embedded and distributed in the body of the building element. These pieces may for example have a dimension of 1 x 1 cm and be present in a density of for instance 1 per cm ³ . An insulating element formed in this way has thanks to the existence of the small aluminium foil pieces a good ability to pre- vent radon gas from passing through, so that it instead will be reflected by the aluminium pieces. An insulating element constituted in this way may for the rest well be provided with a device in joints described above in connection with Fig 1-3.

Building elements 26 according to a further embodiment of the invention are schematically illustrated in Fig 6 and 7, which in the case shown have a device in joints of the kind shown in Fig 1-3 and they are for the rest provided with one or more air channels 27 extending between the sheet planes and therealong, said channels being created by laying perforated plastic tubes 28 in the elements 26 when moulding them. It is possible to provide the elements with an amount of air channels in this way which preferably are interconnected on any place, for example by transversal channels extending between channels extending parallelly to each other. The air channels are so arranged that they in jointly interconnecting two building elements 26 will come into mutual alignment for communication therebetween. These air channels are intended to be connected to means indicated in Fig 7 by a fan symbol 29 for generating a negative air

pressure in the channels, so that substances, such as moisture and ra¬ don gas, entering thereinto will be sucked away from the insulation through the air channels and preferably be emitted to the ambient atmos¬ phere. The negative air pressure may be created by fan means, but it is also possible that it is provided solely by connecting the air channels to the draught air channels of the building. As indicated in Fig 6 and 7, a coating of the building elements with aluminium foil 9 may also be carried out here so as to make these even more unwilling to let radon gas through, and it is also possible to improve this feature further by providing also these elements with aluminium foil pieces embedded in the insulat¬ ing bodies in the way described above.

The invention is of course not in any way restricted to the preferred em¬ bodiments described above, but several possibilities to modifications thereof would be apparent to a man skilled in the art without departing from the basic idea of the invention.

It would for instance be possible to produce the building elements of any other material than indicated above and construct the engaging means in another way as long as the described function is maintained.

It is also conceivable to provide the building element with more than one rib and groove at one and the same border, so that for instance a series of thin ribs and narrow grooves being substantially mutually parallel could be arranged along a border for engaging into corresponding means of an adjacent element.

It would also be possible to altematingiy arrange ribs and grooves along a border of the element and extending substantially perpendicularly to the sheet plane surfaces, so that the free end surfaces of the ribs and the bottom of the grooves are directed substantially parallelly to the sheet plane surfaces. The elements could then be intended to be brought into engagement with each other by a relative movement thereof substantially perpendicularly to their sheet planes by the fact that the ribs converge and the grooves diverge in substantially corresponding degree in the di¬ rection substantially perpendicular to the sheet plane surfaces and ac¬ cordingly in the longitudinal directions thereof. The short sides of the ribs

are here also to be considered as the free ends thereof and comprised by the definition in the claims.

It is also conceivable to make the device for producing a building element mobile and preferably so designed, that it may be brought into very nar¬ row spaces and there eject a mixture of the components required for forming foamed plastic as well as aluminium foil pieces for solidification of this mixture into a building element. The device could then be without means for preparing the mixture and instead be connected to a source for supplying the mixture already prepared to the device.