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This application is a continuation-in-part of Ser. No. 09/403,448 filed Mar. 6, 2000 now U.S. Pat. No. 6,282,859, which is a 371 of PCT/EP98/02125 filed Apr. 2, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a building system and, in particular, to a building system comprising individual building elements connected together by connecting elements adapted therefor. 
     BACKGROUND OF THE INVENTION 
     The invention relates to a building system comprising individual building elements, each element having an upper and a lower surface which are substantially parallel to each other and each building element having at least one opening extending from the upper surface to the lower surface, the building elements being such that they can be positioned on top of each other so that openings of different elements are aligned with respect to each other, and wherein a connecting element can be placed in each opening whereby a first building element belonging to it can be pressed to a second building element located immediately below the first building element, which connecting element of each first building element acts on the upper surface of that first building element and is connectable to the connecting element belonging to the second building element. 
     In the actual building systems the building elements or building blocks are positioned on top of each other whereby the building elements or building blocks can be connected to each other by different systems. In the most traditional system use is made of cement in order to connect two building elements which are positioned on top of each other or are put side by side. In other systems, commonly called quick building systems, use is made of liquid or paste-like glues in order to connect the building elements to each other. In these systems the building elements according to the preamble can be used as well, the openings being made either to reduce the weight of the building elements and improve the insulating characteristics, or to accommodate lines or the like, or to increase the active surface for the glue or the cement. 
     The known building systems all have the disadvantage that they are unsuitable for the unskilled man. During the placing of the building elements and the mutual connecting, the building elements must be positioned accurately with respect to each other and simultaneously they must be connected to each other. This requires the preliminary installment and positioning of adjusting profiles, a wire being stretched there between at the right level along with the next layer of building elements can be positioned and connected. The connection of the building elements requires the availability of a connecting agent such as cement or glue. The handling thereof is not always easy for the unskilled man, as specific requirements must be met with respect to the physical properties during its application, especially with respect to its viscosity. This all has resulted in the fact that the building of walls and the like is not done by the do-it-yourself man, but that as a rule the help of a skilled man is invoked to fulfill this task. Further, the traditional building systems as a result of the connecting means used have the disadvantage that the building height of a wall per time unit is restricted, as the connecting agent needs some time to harden and to obtain the required strength before additional height can be added. When afterwards a building made out of traditional building elements must be broken down, the renewed use of the building elements is generally impossible or labour intensive and therefore not very effective. The cement or the glue must be seen as waste whereas the building elements only partly and only with great efforts can be made suitable for renewed use. In most cases a substantial portion must be accepted as waste. 
     In FR-A-2.473.590 there is disclosed a building system as described in the preamble of claim 1. In this known system each building element is provided with grooves extending around the building element. When two building elements are placed on top of each other with the groove in the lower surface of the top element in line with the groove in the upper surface of the bottom element, a first connecting element can be provided having a strip-like shape with an upper and lower groove provided with holding means. A second connecting element can be snapped in the lower groove of the first connecting element and the upper groove of a lower first connecting element, thereby pressing together the different building elements. The second connecting elements are positioned in the portion of the grooves on the side walls of the building element. 
     This known system has the disadvantage that the connection between the different layers is made by so-called saw-teeth connections (ratchet teeth) allowing only very discrete positioning of the connecting elements, and thereof on irregular pressure distribution between the different layers of the building elements. As a result thereof it is somewhat unpredictable whether two super-imposed building elements have been pressed together with the required pressure to ensure a sufficient stability of the erected wall. 
     In FR-A-1.487.332 there is also described a system as disclosed in the preamble of the main claim. Herein the connecting element is formed as a bolt, one end being a threaded end and one and being shaped as a nut with greater cross-section. The vertical openings in the building element are shaped as bores and between the bolt and the wall of the bore an elastically deformable material has been provided. 
     Upon screwing one bolt on top of another already positioned inside a bore will the elastic material surrounding it, this elastic material is deformed and pressed against the wall of the bore. In this way the connecting elements or bolts are unified with the building elements, and this allows the different building elements on top of each other to be pressed together. 
     It might be possible to press two superimposed building elements together with a defined force but no information is given about that. Otherwise the fixation of the connecting element to each individual building element will generate important forces on the material of the building element. As these lateral forces generate tensions in the material of the building element it is highly susceptible to break, and thereby loosing the fixation. This is especially the case with building materials such as cement, which normally have a very low resistance against tension forces. 
     It is an object of the invention to provide a building system as elucidated in the preamble wherein the above mentioned disadvantages are avoided. 
     This object is achieved in that a deformation member has been applied between the lower surface of the first building element and the connecting element of the second building element, which is deformed by a first predetermined force, thereby inducing a stress in the connecting element of the first building element, and that each first building element is pressed with a second predetermined force to a second building element. 
     Other characteristics and advantages of the invention will become clear from the following description and annexed drawings. 
     SUMMARY OF THE INVENTION 
     In general, the present invention comprises a building system comprising a plurality of individual building elements and connecting mechanisms. Each of the building elements has an upper and a lower surface which are substantially parallel to each other and at least one opening extending from the upper surface to the lower surface, each of said building elements being adapted for alignment with respect to an opening in another building element, each of said connecting mechanisms being dimensioned to fit within and extend through an opening in a building element, each of said connecting mechanisms interconnecting a plurality of associated building elements and a plurality of deformation members, said deformation members being positioned between a lower surface of a first building element and a connecting mechanism of a second building element, said deformation member being deformable by a predetermined force to induce a stress in said connecting mechanism of said first building element such that each of said first building elements is pressed with a second predetermined force to a second building element. 
     In an embodiment, the connecting mechanism may comprise a rod which has one end provided within an enlarged portion to enable it to rest on shoulders in the openings of the building elements. One end of the rod fixes to a building element and the other end has an enlarged portion that presses against an upper surface of another building element. The enlarged portion may have a threaded bore for accommodating a lower end of a rod of another building element and the upper and/or lower surface of the building elements has a cut-out for accommodating the enlarged portion of the rod. Additionally, the surfaces may have gutters ending in side walls through which rods can be positioned to connect gutters of associated building elements to form a lateral connection. Other embodiments of the present invention will become apparent from a perusal of the following detailed description taken in connection with the accompanying drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a building element which can be used in a building system according to the invention. 
     FIG. 2 is a cross section according to the line II—II in FIG.  1 . 
     FIG. 3 is a schematic cross section of a number of superimposed building elements which are connected to each other by means of the system according to the invention. 
     FIG. 3A is a schematic cross section of a number of superimposed building elements which are connected to each other by a means of the system according to one embodiment of the invention. 
     FIG. 3B is a schematic cross section of a number of superimposed building elements which are connected to each other by means of the system according to one embodiment of the invention. 
     FIG. 4 is a cross section, on enlarged scale, of the connecting element placed between two building elements, the connection being made according to the invention. 
     FIG. 5 is a cross section corresponding to the cross section of FIG. 3 of a second embodiment of a building system according to the invention. 
     FIG. 6 is a cross section corresponding to the cross section of FIG. 4 of the second embodiment of the building system according to the invention. 
     FIG. 7 is a top view of a building element according to the invention which is modified with respect to the embodiment of FIG.  1 . 
     FIG. 8 is a cross-section according to the line VIII—VIII in FIG.  7 . 
     FIG. 9 is a view corresponding to the view of FIG. 6 of a third embodiment of a connecting system for the building system according to the invention, shown in the condition before the real connection takes place. 
     FIG. 10 is a view corresponding to the view of FIG. 9, after the two building elements have been connected to each other. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the FIGS. 1 and 2 there is shown a building element  1  which can be used for realizing the building system according to the invention. In the embodiment shown the building element  1  has the shape of rectangular block, having an upper surface  2  and a lower surface  3 , two short side walls  4  and  5  and two long side walls  6  and  7 . This building element  1  can be made out of a number of materials, such as natural materials as used in the traditional building blocks, e.g. bricks, as thermoplastic or resin-type materials. Preferably the building element is made out of sand-lime or concrete, as these materials present the required combination of correct measurements, low cost-price with suitable thermal, mechanical and acoustic properties. 
     In order to be able to connect the building elements  1  to each other so that a building system is obtained, each building element  1  is provided with at least one opening extending from the upper surface  2  until to the lower surface  3 . In the description and also in the drawings the expression opening is used, and in the further description this opening has the shape of a bore with circular cross-section. However it should be clear that the invention is not restricted to circular bores, but that basically any opening extending between the two named surfaces having any cross-section can be used. In the embodiment shown two such openings  10  and  11  have been provided. The ends of the openings  10  and  11  located near to the upper surface  2  are provided with cut-outs  12  and  13  having a cross-section which is larger than the cross-section of the openings  10  and  11 , and the cut-outs  12  and  13  are concentric with respect to the openings  10  and  11 . In the same way and close to the lower surface the openings  10  and  11  are provided with cut-outs  14  and  15 , which in the embodiment shown have the same shape as the cut-outs  12  and  13 , but in principle they can have a different shape and in some circumstances they can be left out completely. In this way the end portions of the openings  10  and  11  are provided with shoulders  16 ,  17 ,  18  and  19 . 
     In order to connect multiple building elements  1  to each other two such elements  1 A and  1 B are put on top of each other one of the openings  10  or  11  of the one element  1 A being positioned in line with one of the openings  10  or  11  of the other element  1 B, and the lower surface of the element  1 A resting on the upper surface of the other element  1 B, as shown in FIGS. 3 and 4. 
     For the connection of two building elements  1 A and  1 B which are put on top of each other, use is made of a connecting element or mechanism  30  as shown in FIG.  3 . In the embodiment shown the connecting mechanism  30  comprises a rod  31  which has one end provided with an enlarged portion  32  by means of which the connecting mechanism can rest against one of the shoulders  16 ,  17 ,  18  or  19  in the openings. The enlarged portion  32  can constitute one unit with the rod, but it might also be a separate unit which during the erection of the wall is provided each time to the end of the rod  31 . The enlarged portion  32  is provided with means for accommodating the end of another rod  31 , in such a way that the two rods are fixed to each other. In the embodiment shown the enlarged portion  32  as seen in the axial direction of the rod is provided with a bore  33  which is provided with a thread, and the rod  31 , or at least the end portion thereof is provided with a thread of the same pitch, the diameter of the thread of the bore  33  corresponding to the thread of the rod  31 . The external surface of the enlarged portion  32  can have the shape of an hexagonal nut, so that it fits to tools by means of which the rod  31  can be screwed on. 
     The length of the connecting mechanism  30  varies to accommodate a plurality of building elements. In one embodiment as shown in FIG. 3, the length of connecting mechanism  30  is basically equal to the height of the building element plus the length of the thread portions extending into the enlarged portion  31  of the next connecting element. In another embodiment as shown in FIG. 3A, the length of connecting mechanism  30  is basically equal to twice the height of the building element plus the length of the threaded portions extending into the enlarged portion  31  of the next connecting mechanism. The connecting mechanism in such embodiment provides for the connection of three building elements. By increasing the length of the connecting mechanism, a greater number of building elements may be connected thereby saving a substantial amount of work, as shown for example in FIG.  3 B. The diameter of the rod is somewhat smaller than the diameter of the openings  10  or  11 , so that the rod can be inserted through the openings  10  or  11  with some tolerance. 
     In order to connect multiple building elements, a rod  31  is inserted through the opening  10  or  11  positioned in line with the opening  10  or  11  of the building element positioned below the first mentioned, so that the enlarged portion  32  is protruding at the upper part. In the opening of the lower building element such a connecting mechanism  30  has already been provided, the now inserted rod can be screwed in the thread of the lower connecting mechanism. By selecting the right dimensions of the building element and the connecting mechanism  30  the rod can be screwed on to such an extent that the last positioned building element is pressed between the enlarged portion  32  of its own connecting mechanism  30  and the upper surface  2  of the lower building element  2 B. By using a suitable tool the force of this pressing can be adjusted to a defined value, e.g. a force of 3000 N so that the composition receives enough pre-stress in a direction perpendicular to the contact surface and friction along this surface, in order to meet (apart from the pressure resulting of the piling up) all cross stresses, bending-stress and local stress as may be expected. 
     In FIG. 3 there is schematically shown how a number of buildings elements are connected to each other by means of the connecting mechanisms  30 . From this drawing it becomes clear how a wall can be obtained in which all the building elements are pressed to each other with the same force. Measurements have shown that basically a force of 1000 N is sufficient to give the wall enough strength against lateral forces. Preferably greater pressure forces between the building elements are used, e.g. of the magnitude of 3000 N. In this way a solid and secure wall can be obtained. With respect to the anchoring it must be remarked that the lowermost layer of building elements can be fixed to a fundament by means of the connecting mechanisms  30 , the fundament being already made before erecting the wall and being provided with hollow elements provided with thread for accepting the lower ends of the rods  31 . If needed, the rods  31  of the lowest layer can be longer than the standard rod length. 
     In case the height of the enlarged portion  32  is smaller than the height of the shoulder  12  or  13 , the enlarged portion  32  falls completely within the shoulder  12  or  13  and the shoulders  14  and  15  at the lower surface of the building elements can be eliminated. In view however of the positioning of the next building element to be placed it is preferred that the enlarged portion  32  is extending somewhat above the upper surface  2 . 
     In the embodiment described above problems may arise when one of the rods  31  breaks, whereby the complete tension force over the height of the wall above the fracture disappears. This can be improved by anchoring at least partly each building element to the building element or elements located above it. How this can be achieved is described with respect to the FIGS. 5 and 6. 
     The system as shown in FIGS. 5 and 6 is substantially identical to the system as shown in FIGS. 3 and 4, except for the presence of a deformation element  35  which has been positioned between the enlarged portion  32  and the shoulder  19  of the cut-out  15 . In the embodiment shown the deformation element is a ring with a truncated conical shape. The dimensions and the material of the deformation element  35  are selected in such a way that the deformation element, as a result of a predetermined force e.g. 1000 N, is deformed in a non-elastic permanent way. It is clear that the invention is not restricted to the embodiment of the deformation element shown, but that it is possible to use other type of deformation elements. Essentially the operation of the deformation element  35  must be such that as a result of a predetermined force a permanent non-reversable deformation is taking place, which force must be substantially smaller than the force whereby the superimposed building elements must be pressed together. 
     The dimensions of the deformation element  35  are selected in such a way that in the horizontal direction it completely fits within the cut-outs  12 ,  13 ,  14  and  15 . The vertical dimension in undeformed condition must be such that the sum of the height of the enlarged portion  32  and the height of the deformation element  35  is bigger than the sum of the heights of the cut-outs  12  and  14  or  13  and  15 . If these conditions are met the following function is obtained. 
     It is assumed that the building system is already composed of a number of layers. Before a new building element is positioned with its openings  10  and  11  in line with the openings  10  and  11  of the building element located immediately below the first one, a deformation element is placed on each enlarged portion  32  which will be used by this new building element for connecting purposes. After positioning of the building element, the connecting mechanisms  30  are inserted through the openings  10  and  11  which extend through the already available deformation elements  35  until to the upper end of the bores  33  in the enlarged portions  32 . When the connecting mechanism  30  is screwed into the bore, the enlarged portion  32  of this connecting mechanism  30  is brought into contact with the shoulder  16  or  17 . From this moment on further screwing of the connecting mechanism  30  will cause the building element to be pressed in the direction of the lower building element. In view of the dimensions as elucidated above, the first place that contact is made is between the deformation element and the shoulder  18  or  19 . As soon as the pressure has reached a defined value, e.g. 1000 N, the deformation element starts deformation until the lower surface of the upper building element is contacting the upper surface of the lower building element. Further screwing of the connecting mechanism  30  will cause the two surfaces to be pressed together until the desired pressure force of e.g. 3000 N has been reached. From this moment on the deformation element  35  is deformed and squeezed between the shoulders  18  or  19  on the one hand and the enlarged portion  32  of the connecting mechanism  30  on the other hand. Thereby the deformation element presses with a force of 1000 N against the shoulder  18  or  19 . 
     In this way it is achieved that each connecting mechanism  30  is anchored on its own and that the force over the height of a number of superimposed building elements is not completely transferred to the lower connecting mechanism. When now for any reason one of the connecting mechanisms is broken or is not any more capable to transfer the stress downwardly, the required stress force in a number of layers is sufficiently built up to guarantee the required anchoring of the system. In view of the large number of connecting mechanisms which are present in a wall made by means of the building system according to the invention, the consequences in case of an interruption in one of the vertical connecting mechanisms are restricted to a local event, which can not extend to the complete height of the wall. 
     In a number of situations it might be desirable to increase the lateral strength of a wall made by means of the building system according to the invention. This can be the case with high walls or in order to connect the inner walls to the outer walls in a construction having a hollow wall. In these situations use can be made of the building element as shown in FIGS. 7 and 8. 
     The building element  39  according to the FIGS. 7 and 8 is substantially identical to the building element according to FIG. 1, except for the fact that the upper and lower surface have been provided with gutters having a semi-circular or U-shaped cross-section. The gutters  40 ,  41 ,  42 ,  43 ,  44  and  45  extend from the edges between the upper surface  2  and the side-walls  4 ,  5 ,  6 , and  7  to the cut-outs  12  and  13  in the upper surface  2 . It is possible that the gutters  40  and  41 ,  42  and  44  and  43  and  45  are extensions of each other and can emerge into each other. In the same way the lower surface  3  is provided with gutters  50 ,  51 ,  52 ,  53 ,  54  and  55  which also extend from the edges between the lower surface  3  and the side-walls  4 ,  5 ,  6  and  7 . In the embodiment shown each gutter  40 - 45  and  50 - 55  is provided with a thread. The location of the gutters  40 - 45  and  50 - 55  is chosen in such a way that when two building elements  39  are placed on top of each other with their openings on one line, at least one gutter in the lower surface of the upper building element is directly opposite one gutter in the upper surface of the lower building element, so that it looks as if one bore provided with thread has been formed. Neighboring building elements may have corresponding bores located on one line with these bores. 
     The operation of the lateral anchoring is as follows. During the erection of the wall two building elements  39  are positioned along each other with their upper surface being the same height and the gutter  41  being aligned with the gutter  40  of the neighboring building element. In this way a nearly common gutter is shaped in the common upper surface of the two building elements. In this gutter a rod provided with thread can be placed in such way that it co-operates with the thread in the gutters  41  and  40  respectively. The positioning of the next layer of building elements  39  is done in such a way that at least one of the gutters  50  or  51  is fitting upon the threaded rod which is placed in the gutters  41  and  40  so that the rod is completely enclosed and a lateral anchoring is formed between the two building elements. There is no need that the building elements are directly in contact to each other. It is possible that two walls together forming a hollow wall are laterally fixed to each other. Further this provides the freedom to adapt the number of lateral anchoring in the height depending upon the circumstances, e.g. by providing lateral anchoring in each layer at the critical levels, and only in defined layers in less critical levels. 
     Furthermore it is possible to use other lateral anchoring than the system with threaded rods as described above. So it is possible to use gutters  40 - 45  and  50 - 55  respectively in which at a defined distance from the edges between the upper surface  2  and the lower surface  3  respectively and the sidewalls  4 ,  5 ,  6  and  7  there are provided cut-outs having a bigger dimension than the cross section of the gutters. The anchoring can take place by means of rods which at both ends are provided with correspondingly shaped enlarged portions. In the most simple embodiment this can be achieved by providing in each gutter at a defined distance from the side walls a bore, cross hole or other enlarged hole perpendicular with respect to the surface of the upper surface  2  or lower surface  3  respectively. The anchoring element may comprise a rod having two end portions bent over an angle of 90°. If such an embodiment is chosen it may be enough to provide a cut-out only in the upper surface or the lower surface. In the same way the threaded bore formed by the two threaded gutters made symmetrically in the upper and lower surface may be substituted by asymmetrical shaped gutter-like holes. This can be achieved by means of a U-shaped gutter in which the threaded rod is completely incorporated and fixed, closed by the completely flat surface of the other building element. A threaded rod can, contrary to a spacing rod (made of bent iron wire), be installed and removed without disassembling the building elements. 
     In the FIGS. 9 and 10 a third embodiment of the building system according to the invention has been shown. This embodiment differs from the embodiments described above in that the connecting mechanism is made out of several parts and by the shape of the deformation element. At the same time the shape of the openings in the building elements has been adapted. 
     The cut-outs  115  and  112  in the building elements  101 A and  101 B shown in FIGS. 9 and 10 correspond to the cut-outs  15  and  12  in the building elements  1 A and  1 B of the FIGS. 3 and 4. The cut-out  115  consists of a conical outer part  160 , a cylindrical intermediate part  161  and a conical bottom part  119  corresponding to the shoulder  19  in FIG.  2 . In the same way the cut-out  112  is composed out of an outer part  170 , an intermediate part  171  and a bottom part  116 . 
     The connecting mechanism consists of a rod  131  which at least near to its ends is provided with thread. The length of the rod corresponds substantially to the height of the building element  101 . Further the connecting mechanism comprises a nut  180  with a height somewhat lesser than the sum of the depths of the cut-outs  112  and  115 . The internal threads of the nut  180  is halfway provided with a stop or the like, whereby it is prevented that the thread end of the rod  131  can be further screwed into the nut  180 . The deformation element  181  consists of a ring the central opening of which has a diameter which substantially corresponds to the outer diameter of the rod  131 , an upright edge  182  being formed around the opening, in such a way that the ring can be slipped over the thread end of the rod with some light clamping force. The outer diameter of the ring is substantially equal to the diameter of the intermediate part  161  and  171  of the cut-out  115  and  112  respectively. Further a closing ring  184  is used with a conical shape which nearly fits to the conical shape of the bottom part  119  and  116  respectively. 
     In order to describe the operation of this embodiment, the starting point is the situation as shown in FIG. 9, wherein it is assumed that the building element  101   b  through the rod  131 , the nut  180  and the ring  184  is pressed against the building element located below it. In order to position the next building element the rods  113  are inserted into the openings  110  and  111  thereof, whereas at the same time over the lower end of the rods  131  there is placed a ring  181  and over the upper end a ring  184  and the nut  180  is loosely screwed to the upper end. In this way the connecting mechanisms remain in position during the manipulation of the building element. If needed the building element can already be prepared in this way during the production of the building elements and being supplied in this form. Thereupon the building element  101 A is placed on top of the building element  101 B in such a way that the lower end of the rod  131  can be screwed into the nut  180  relating to the building element  101 B. By means of a suitable tool fitting to the nut  180  screwed onto the rod  131  of the building element  101 A, the nut is initially screwed further on the upper end, until it reaches the internal stop, after which the rod  131  starts to turn together with the nut. During further screwing the ring  184  will contact the bottom part  116 . In this way it is obtained that the rod  131  is centralized in the opening  110 . During further screwing of the nut and rod the upper end of the nut  180  will press against the deformation element  181 . After reaching a defined pressure force, e.g. of 1000 N the element  181  will deform in such a way that ultimately it is compressed between the nut  180  and the bottom part  119 . At the same time the building element  101 A is pressed against the building element  101 B until the pressure force has reached a value of e.g. 3000 N. Further screwing of the nut and the rod is stopped. FIG. 10 shows how the combination of ring, nut and deformation element are positioned after the screwing of the nut and rod has been terminated. 
     It is clear that in this way an anchoring of the building elements has been obtained which practically corresponds to the system described with respect to FIGS. 5 and 6. The advantage of the third embodiment is that the connecting mechanism is completely composed of parts which are normally commercially available and therefor need not to be manufactured in a special way. This may result in a substantial saving in the cost price. 
     It will be clear that the invention is not restricted to the embodiments described and shown in the drawing, but that numerous modifications can be applied within the scope of the inventive idea such as expressed in the claims.

Summary:
A building system comprising a plurality of individual building elements and connecting mechanisms, wherein each of the building elements has an upper and a lower surface which are substantially parallel to each other and at least one opening extending from the upper surface to the lower surface, and each building element is adapted for alignment with respect to an opening in another building element. Each connecting mechanism is dimensioned to fit within and extend through an opening in a building element and interconnect a plurality of building elements and deformation members. Deformation members are positioned between a lower surface of a building element and a connecting mechanism of another building element, and deformable by a predetermined force to induce a stress in the connecting mechanism of a building element such that it is pressed with a second predetermined force to another building element.