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OBJECT OF THE INVENTION 
       [0001]    The present invention refers to an underground dwelling that has been specially conceived to have the characteristics of a natural cave, but having the advantage of being of a modular nature and therefore being susceptible to industrialization, something that had not been possible up to now. 
         [0002]    The object of the invention is to provide the market and the public in general with the possibility of acquiring an underground dwelling that is assembled modularly or prefabricated and that is mostly covered by the earth of the site where it has been installed, as if it was a natural cave. 
       BACKGROUND OF THE INVENTION 
       [0003]    Artificial caves, such as the one described in the Spanish Utility Model N o  248,970, based on a metal framework or an otherwise rigid framework having the appropriate shape, on which it is applied a layer of the material obtained by mixing a fibrous material (paper, cloth, fabric, asbestos or wild cotton) with a setting or thermosetting product (glue, plaster, gypsum, mud, thermosetting plastic) and obtaining with this mix a hollow body, irregularly shaped, open at the frontal part and having excrescences and recesses that simulate the appearance of rock, and even the appearance of stalactites and stalagmites, all of it configuring a body that simulates an artificial cave. 
         [0004]    Said type of cave, although designed to be materialized in several shapes has mostly an ornamental function, and has never been intended or designed to be used as a dwelling. 
         [0005]    However, there are natural caves that have been inhabited as dwellings, although they are very limited in many functional aspects, since they have been made by simply excavating the terrain and are therefore not susceptible to the process of industrialization. 
       DESCRIPTION OF THE INVENTION 
       [0006]    The underground dwelling object of the invention can be considered as a cave dwelling, but obtained by assembling three dimensional modules that may be part or the whole of the dwelling, endowing it with its eminently industrializable nature. 
         [0007]    In this sense, a terrain having certain degree of elevation is excavated creating a cavity or hollow, and on this cavity the three dimensional module, preferably cast in concrete, is placed. Said module having, at least, an opening that will serve as access to the inside, and this prefabricated module may also have openings for windows and holes as chimney flues, air vents, light wells, etc., all of it assuming the module will constitute in itself the entire dwelling, since the dwelling can be configured by several joined or assembled modules that will be preferably configured by complementary tongue and groove elements built in the design of the attachable walls, since the modules can be assembled laterally to each other, or even stacked on top of each other to form a two rooms dwelling, or also configure a set of different dwellings by placing and coupling the necessary modules once the terrain has been excavated. 
         [0008]    In all cases, one or more modules will be fitted with the aforementioned openings to serve as chimneys, vents, etc., and will be also fitted with the appropriate access opening that can also serve as means of communication between the several modules when a dwelling has two or more modules. 
         [0009]    The module or modules of the dwelling or dwellings will be covered, except for the wall that has the access and windows openings, by a thick layer of earth, which favors thermal conditions both in summer and winter. 
         [0010]    It is apparent that the modules may be formed by conveniently matching panels to form the walls and the ceiling. 
         [0011]    It is also apparent that with the solution thus described, underground dwellings type caves may be obtained by industrialization processes, since they are made of prefabricated models that are placed in a cave or excavated hollow in a terrain having the appropriate orography to allow the module or modules to be covered with the layer of natural earth fill obtained as a by product of the excavation process. 
         [0012]    Although the modules may be preferably made out of concrete, any other appropriate material is not ruled out, such as sandwich type panels made of insulating and even fireproof materials, polyurethane, etc. 
         [0013]    The frontal or facade panel of the dwelling, regardless if said dwelling one or several modules, may be taller than the remaining panels, said bigger frontal height acting as a barrier for possible land sliding events and preventing that the earth load fall on said facade or anterior part of the dwelling. 
         [0014]    Also the dwelling may incorporate a couple of apses on the sides that are part of the dwelling unit and act as enlargement of the main space, and also contributing to lend a larger plane to the whole to decrease the effects that erosion may have on the unit. 
         [0015]    It has also been incorporated into the plan that the side panels may be joined by groove and tongue panels, by welding, by fitting between the edges of the panels to be thus joined, by anchoring one panel on the other, etc., with or without complementary elements used to secure the anchoring such as screws, bolts, rivets and similar elements, while to secure the panels used for the overhead closure tongue and groove plates having known anchoring means such as those described immediately above, screws, bolts, rivets, etc., are used. 
         [0016]    Affixing the module or modules to the terrain may be done by solid concrete piers or footing elements conveniently deployed on the terrain, which upper sides will be fitted with metal plates to which other complementary metal plates will be welded facing the lower plates so the lower side of the panel or panels that constitute the base of the module or modules will be facing said complementary metal plates. 
         [0017]    Finally, the joints formed by the joined panels will be complemented with a putty fill or with another product or material that prevents the passage of particles, insects, humidity, etc., that is, a fill material that provides insulation and water-tightness to the indoor space formed by the joined modules. 
         [0018]    The underground dwelling object of the invention constitutes what can be considered as a cave dwelling, inside which several different uses and applications can be considered, using multiple materials, sizes and appearances, with the door, windows and other appropriate necessary accessory elements that are needed and that can be manufactured without limitation to the extent of their surface area, can be produced in several heights with the structure plans adapting it to each dwelling. 
         [0019]    The underground dwelling that constitutes a sort of cave dwelling offers also high quality characteristics, it is environmentally sound and of craftsmanship quality, is produced at a low cost and is extremely simple. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    To complement the description provided in this section, and to better aid in the understanding of the characteristics of the invention, a set of drawings have been attached to this descriptive report. The figures in the drawings depict the innovations and advantages of the underground dwelling object of the invention. 
           [0021]      FIG. 1 . Shows a section view of a module set in a cavity excavated in the terrain, showing on one of the walls or panels the access opening to the dwelling that will configure said module as well as a vertical upper conduit that may correspond to a chimney flue, a vent, etc. 
           [0022]      FIG. 2 . Shows a schematic plan view of an example of modularity involving several modules collaterally joined together to form a dwelling or several rooms or spaces, and even several dwellings that attached together. 
           [0023]      FIG. 3 . Shows a frontal perspective view of an example depicting several dwellings formed by different modules assembled on the excavated site. 
           [0024]      FIG. 4 . Shows a frontal perspective view of another example of an underground dwelling done according to the stated object of the invention, where it can be observed how the facade panels are taller than the remaining panels used to assemble the different rear modules of the dwelling or dwellings in question. 
           [0025]      FIGS. 5 ,  6 ,  7  and  8 . Show the corresponding details of other means of collaterally affixing the panels of the modules corresponding to the underground dwelling or dwellings. 
           [0026]      FIG. 9 . Shows a detail of a possible manner to assemble the ceiling panels 
           [0027]      FIG. 10 . Shows a detail of a preferred manner of affixing the bottom or base panel or panels to the terrain. 
       
    
    
     PREFERRED EMBODIMENT OF THE INVENTION 
       [0028]    In view of the figures described above, and referring specifically to  FIGS. 1 ,  2 , and  3 , a three dimensional module  1  can be observed, preferably cast in concrete, that can constitute a dwelling in itself, said module includes an access opening  2  leading inside the module and therefore inside the dwelling, as well as one or more holes placed in the upper regions superiorly to said opening to function as vertical ducts  3  that may be used as chimneys  4 , vents with natural light inlets  5 , etc., in such a manner that module  1  is implanted in an excavated site dug to that effect on terrain  6  having one or several walls or lateral sides with complementary coupling elements  7  and  7 ′ that are correspondingly male and female to couple adjacent modules, coupling that may be tongue and groove by virtue of this male-female configuration of said coupling means  7  and  7 ′. 
         [0029]    The dwelling obtained based on the three dimensional module  1  may have several rooms or spaces, that are formed by collaterally joining several modules  1  or even assembling them vertically, that is, at different heights.  FIG. 2  shows such an example of modular assembly formed, specifically by four similar modules  1  arranged in an arc or arranged in a segmented line pattern by intersecting triangular modules  1 ′ to form said broken or arched configuration, forming what can be considered as a several rooms dwelling, or several attached dwellings collaterally joined together through the complementary coupling means  7 - 7 ′ fitted to the side walls of said spaces, that is, the side walls of modules  1  and  1 ′. 
         [0030]    As it is apparent, modules  1  and if appropriate modules  1 ′, will be prefabricated modules, preferably made of concrete, although other appropriate materials are not ruled out, that configure an underground dwelling type cave since the module or modules are covered with the natural earth fill resulting from the excavation of the terrain  6  required to open the space to install the underground dwelling type cave. 
         [0031]      FIG. 3  shows a perspective of the setting of several modules  1  located in an excavated hollow or hollows on terrain  6 , according to special configurations of said modules  1 . One of the modules in the figure shows an access door  8  that will be installed in the corresponding opening  2  of module  1 , and having also windows  9  planned in the design of the corresponding prefabricated module  1 , this  FIG. 3  also showing chimneys  4  corresponding to ducts  3  shown in  FIG. 1  and vents or light wells  5  established in said ducts  3 , all of it designed and sited in such a manner that when the modules are attached together, as shown in  FIG. 2 , or even in  FIG. 3 , if it is a single dwelling, they will be closed or will only be fitted with opening  2  to hang the corresponding access door  8 , while if the modules are intended to configure one or several spaces of the same dwelling, these modules will have openings to communicate said spaces of the same dwelling. 
         [0032]      FIG. 4  shows an underground dwelling obtained according to the information described above, including a facade  10 , an overhead enclosure  11  and a coating  12  that maybe the earth fill resulting from the excavation of site  6  shown in  FIG. 3 , and the facade  10  having the appropriate opening  13  to fit the main access door to the inside of the dwelling, as well as openings  9 ′ to fit the windows. 
         [0033]    Also in  FIG. 4 , the panels configuring facade  10  are taller than the remaining panels, that is, they stick out above the overhead enclosure  11  to form a barrier preventing potential landslides or earth movements from accessing the facade or the anterior part of the dwelling. 
         [0034]    Laterally, it presents one apse  14  that besides providing the general aspect of the dwelling with a flatter dimension, it provides an enlargement and protection against erosion. 
         [0035]    The joining of the different lateral panels referenced in  FIGS. 5 ,  6 ,  7  and  8  with numbers  15  and  15 ′ may be done in many different ways. For example,  FIG. 5  shows how panels  15  and  15 ′ include a double zig-zag shaped staggered edge  16  that determines a means of coupling or joining together said panels. 
         [0036]    On the other hand,  FIG. 6  shows how said panels  15  and  15 ′ are joined by housing the upper edge of panel  15  in a groove  17  established in panel  15 ′, said joint or coupling being made secure by anchoring elements  18  such as screws, bolts or similar. 
         [0037]      FIG. 7  shows how panels  15  and  15 ′ are secured by welding  19 , while in  FIG. 8  said joining is shown to be done by anchoring elements  20  that are through elements, for instance going through panel  15 ′ and being affixed to panel  15  or vice versa. 
         [0038]    The joining means of ceiling panels  21  and  21 ′, as shown in  FIG. 9 , can be done by tongue and groove elements  22  complemented by anchoring elements  23  similar to anchoring elements  10  mentioned above, and provided at the joining plane of side panels shown in  FIG. 6 . 
         [0039]    Finally, the joining means of the base or floor panel  24  to the terrain  25  is done by metal plates  26  fitted to the upper surface of a pier  27  placed to that effect on terrain  25 , while the lower side of the base or floor panel  24  of the module is fitted with other metal parts  26 ′ complementary to parts  26  and placed so they faced each other so they can be welded together to achieve the joint, and in this manner the module is perfectly secured by its base to the piers  27  placed on the terrain  25 .

Summary:
The invention relates to a dwelling formed by one or more preferably concrete three-dimensional modules ( 1  and  1 ′) which are provided with complementary coupling means ( 7  and  7 ′) so that the modules can be positioned side by side and/or on top of one another in order to form a dwelling with several rooms or even several dwellings. The invention includes an access ( 2 ) to the interior, windows ( 9 ) and ports for pipes ( 3 ) for chimneys ( 4 ), vents and lighting outlets ( 5 ). The constituent modules ( 1  and  1 ′) of the dwelling(s) are installed in a trench or cave formed in suitable terrain ( 6 ) and, except for the access wall containing the door ( 8 ) and/or the windows ( 9 ), are covered completely with natural soil corresponding to the terrain ( 6 ) excavated in order to install the modules ( 1  and  1 ′) and the dwelling(s).