Abstract:
The present invention, in one embodiment, is directed to a prefabricated wooden panel comprised of: (a) a series of first elongated wooden means, each with mating faces, (b) a series of elongated reinforcement means, each located between a pair of the first elongated wooden means, (c) a series of perforations or through-holes that extend through the first elongated wooden means and elongated reinforcement means, (d) a series of tensioning means that each extend through one of the perforations, and (e) a series of pairs of first stress transmitting means with each member of a pair engaging an end of one of the tensioning means.

Description:
DESCRIPTION OF THE PRIOR ART  
       [0001]     The present invention corresponds to a prefabricated structural panel of post-stressed wood that can be used in the manufacture of immovable properties or buildings.  
         [0002]     The construction of wooden panels is a highly requested activity in the industry of immovable property construction. Said panels should be capable to suitably satisfy the requirements of the real estate project as well as involve competitive costs. Among said requirements, the structural strength, thermal insulation, acoustic insulation, durability, versatility, simple and fast manufacture can be mentioned.  
         [0003]     Numerous documents exist in the state-of-the-art, which propose diverse solutions to the problem of wooden houses construction. Reference can be made to the foreign documents described below:  
         [0004]     The Japanese patent JP 7305413 discloses the utilization of prefabricated wooden panels made of trunks, which are joined by means of elongated metal tensioning means, which pass through holes in the trunks of said panels. These tensioning means are stressed by nuts screwed at the ends with the thread of the tensioning elements. The panels are manufactured on industrial basis and then assembled during the corresponding immovable property construction.  
         [0005]     The invention disclosed in the above mentioned Japanese patent JP 7305413 shows the next to technical problems:  
         [0006]     (1) The wood is not efficiently used, since the geometry of said panels does not offer a good structural performance; for this reason, in order to offset the above, the panels use excessive wood that cause them to be relatively heavy; this increases their production and transport cost, further to hindering their handling during the installation.  
         [0007]     (2) The arrangement of the tensioning means, together with the stress they exercise, do not permit that the panels can use in their manufacture wood pieces whose dimensions are smaller than the panel full length; this constitutes a second feature that prevents the efficient use of the wood and considerably increases the cost of each construction.  
         [0008]     (3) The nuts used to stress the tensioning means in said panels can eventually become loose, and this would affect the panel structural performance.  
         [0009]     (4) With a view not to damaging the tensioning means thread in the course of the panels installation, special care should be used, which reduces the efficiency of the process.  
         [0010]     (5) Since the stress is transmitted through the nuts and threads, quality steels and/or larger sections are required, a condition that increases the panel relative cost.  
         [0011]     The US patent U.S. Pat. No. 5,081,811 discloses the utilization of wood panels made of trunks, joined by means of metal elongated tensioning means passing through holes across the trunks of said panels. In addition, said tensioning means are joined to a device that a absorbs the trunks expansions and contractions this prevents the loosening of the panels, a condition that would affect their structural performance. Said expansions and contractions are normally produced by the change of humidity and temperature affecting the trunks, and are caused by the variation of the environmental conditions.  
         [0012]     The invention disclosed by said US document (U.S. Pat. No. 5,081,811) presents the technical problems listed below:  
         [0013]     (1) These panels are not industrially prefabricated; they should be made in situ, and this increases their cost.  
         [0014]     (2) The wood is not efficiently used because of the fact that the geometry of said panels does not have a good structural performance; thus, with a view to compensating this condition, the panels use excessive wood, making them relatively heavy and this increases their cost and makes their installation difficult.  
         [0015]     (3) The arrangement of the tensioning means, together with the stress exerted by them, do not permit that the panel use for their manufacture pieces of wood having smaller dimensions as compared to the panel full length; the latter represents a second fact that prevents the efficient use of the wood and substantially increases the cost of each construction.  
         [0016]     Based on the above mentioned information, it is concluded that in the technical field of wooden prefabricated panels construction new inventions have not been made that, together with an efficient utilization of the wood, permit the industrial and large-scale manufacture of prefabricated structural wooden panels, which can be subsequently transferred and installed in a simple, fast and economic manner, and which adequately meet the requirements of structural strength, thermal and acoustic insulation, durability and versatility.  
       DESCRIPTION OF THE INVENTION  
       [0017]     The present invention relates to a prefabricated structural panel of post-stressed wood ( 1 ), which easily solves the technical problems referred to in the prior art.  
         [0018]     The wooden prefabricated structural panel ( 1 ) of the invention comprises a series of first elongated wooden means ( 2 ), whose cross-sections have at least two opposing faces ( 3 ) male and female ( 4 ) having a flat or any other suitable geometry, wherein the male face ( 3 ) of a first wooden elongated means ( 2 ) is assembled with the female face ( 4 ) of a corresponding first adjacent elongated wooden means; a series of first perforations or through holes ( 5 ), which cross said male ( 3 ) and female ( 4 ) faces of each of the first elongated wooden means ( 2 ), which generates a series of first common cavities ( 6 ) that connect each of said first elongated wooden means ( 2 ) when placed adjacent to each other; a series of first stress means ( 7 ) correspondingly located inside said first common cavities ( 6 ), whose corresponding ends ( 8 ) are projected outside said cavities; a series of corresponding pairs of first stress transmitting means ( 9 ) joined to the corresponding ends ( 8 ) of said first stress means ( 7 ), which contact the ends of the wooden panel ( 1 ) and transmit into said ends the force exerted by the first stress means ( 7 ).  
         [0019]     Said wooden panel further comprises a series of elongated reinforcing means ( 10 ) made of wood and/or other suitable material, which possess faces ( 11 ) and first holes or perforations ( 12 ) coinciding with those of the first elongated wooden means ( 2 ) and are located between some of said pairs of adjacent first elongated wooden means ( 2 ), where said elongated reinforcement means ( 10 ) have an essentially greater bending strength than that of the first elongated wooden means ( 2 ) in respect to the axis, which is perpendicular to the longitudinal axes of said first elongated wooden means ( 2 ).  
         [0020]     Said series of first tensioning means ( 7 ), jointly with the series of corresponding pairs of first stress transmitting means ( 9 ) are conveniently dimensioned in order to exert a force between the corresponding male face ( 3 ) and female face ( 4 ) of each of said pairs of corresponding elongated adjacent means ( 2  with  10  or  2  with  2 ), being sufficiently large so that the friction force generated between same prevents the relative movement of them, so as to obtain that said elongated means jointly act as a collaborating structural panel.  
         [0021]     The collaborating character of the invention panel, which is achieved thanks to the combination of high stress levels, transmitted by said first tensioning means ( 7 ) together with the utilization of reinforcement elongated means ( 10 ) conveniently located between some of said first elongated wooden means ( 2 ) provide an outstanding structural performance to the panel, together with an efficient use of the wood.  
         [0022]     The first tensioning means ( 7 ) are made of metal or other suitable material and the stress to which they are subjected is smaller than their flow stress or permanent strain stress, although it is sufficiently high to permit them to have an elastic behavior, in spite of the contractions and expansions suffered by said wooden panels ( 1 ), which are caused by changes of humidity and room temperature.  
         [0023]     The cross-section of the male ( 3 ) and female ( 4 ) faces of said first elongated wooden means ( 2 ) may conveniently have the geometry of an arrow point, a flat surface or other adequate geometry. The arrow point geometry is preferred when the involved adjacent means are two of said elongated wooden means ( 2 ). The flat geometry is preferred when the face of the corresponding first elongated wooden means ( 2 ) corresponds to one of the end faces of the wooden panel ( 1 ) or when one of said first elongated wooden means ( 2 ) contacts one of said elongated reinforcement means ( 10 ).  
         [0024]     By way of example, the first elongated means can be made from wooden piece of standard dimensions, with a 2″ (50.8 mm) by 3″ (76.2 mm) rectangular cross-section, having one of its longer sides arranged parallel to the panel main plane. Furthermore, said reinforcement means can be made from wood pieces of standard dimensions, of 1″ (50.8 mm) by 4″ (101.6 mm) rectangular cross-section, where one of its shorter sides is arranged parallel to the panel main plane.  
         [0025]     Said pairs of first stress transmitting means ( 9 ) may comprise metal plates ( 9   a ) or made of another suitable material, which are supported on the end faces of said first elongated wooden means ( 2 ), located at the ends of the wooden panel ( 1 ) and joined by means of welding or other adequate means to said first tensioning means ( 7 ).  
         [0026]     The pairs of first stress transmitting means ( 9 ) may comprise profiles made of metal or other suitable material having an “L”-shaped ( 9   b ) or other adequate cross-section, being supported by means of one their faces on the extreme faces of the first elongated wooden means ( 2 ), located at the ends of said wooden panel ( 1 ) and joined by means of welding or other suitable means to the first tensioning means ( 7 ); the other face of said “L”-shaped ( 9   b ) or another suitable section is supported on the side of the wooden panel ( 1 ).  
         [0027]     Said series of first tensioning means ( 7 ) comprises at least six tensioning means located inside of at least six corresponding first common cavities ( 6 ). This feature permits that said tensioning means ( 7 ) exert a homogeneous stress profile on said panel, thereby improving its structural performance.  
         [0028]     Each of the first elongated wooden means ( 2 ) is formed by one or more pieces of wood of the same or different dimensions, which are respectively joined one next to the other until they reach the full dimension of panel ( 1 ). This is possible because the above mentioned tensioning homogeneous profile, jointly with the series of first tensioning means ( 7 ) and causes a great impact on the reduction of cost of panel ( 1 ), since it permits a very efficient use of the wood in view that it is not restricted to the use of wooden means only having the total dimension of the panel, and even fragments of different wood measures can be used.  
         [0029]     The series of first elongated wooden means ( 2 ) can consist of dry and treated wood, which makes them resistant to termites and other problems commonly affecting the wood, further to improving their resistance to humidity. The latter feature significantly increases the wooden panel ( 1 ) duration and reduces the contractions and expansions suffered by it as a result of the change in the environmental conditions.  
         [0030]     The reinforcement means ( 10 ) can be made of wood, metal, polymers or other adequate materials. They can also be simultaneously made up of several materials, such as wood [ 10   a ] internally or externally reinforced with metal [ 10   b].    
         [0031]     The first tensioning means ( 7 ) can be made of metal or other suitable material; the stress to which they are subjected is smaller than their flow stress or permanent deformation stress, although it is sufficiently high to provide them with an elastic behavior, in spite of the contractions and expansions suffered by said wooden panels ( 1 ) caused by changes of humidity and temperature, which in turn are due to changes in the environmental conditions.  
         [0032]     The cross-section geometry of said first elongated wooden means ( 2 ) and the elongated reinforcement means ( 10 ) can be conveniently modified in order to vary the structural characteristics of the wooden panel ( 1 ).  
         [0033]     Said wooden panel ( 1 ) may also comprise a series of second elongated wooden means ( 13 ), whose characteristics are analogous to those of the first elongated wooden means ( 2 ), together with a series of second tensioning means ( 14 ) having analogous characteristics to those of the first stress means ( 7 ) and a series of pairs of second stress transmitting means ( 15 ), of similar characteristics to those of the first stress transmitting means ( 9 ); said series of elongated reinforcement means ( 10 ) may comprise a series of second perforations ( 16 ), conveniently displaced with respect to said series of first perforations ( 12 ), through which said second elongated wooden means ( 13 ), jointly with the series of second tensioning means ( 14 ) and the series of pairs of second stress transmitting means ( 15 ) can be joined to the structure of the wooden panel ( 1 ), in a similar manner to that in which first elongated wooden means ( 2 ), the series of first tensioning means ( 7 ) and the series of pairs of first stress transmitting means ( 9 ) are joined to the structure of the above mentioned wooden panel ( 1 ) through said first perforations ( 12 ).  
         [0034]     The invention envisages the use of optional means tat permit to re-stress said first ( 7 ) and second ( 14 ) tensioning means, were it necessary.  
         [0035]     The above described wooden panels ( 1 ) can be industrially constructed in a large scale, due to the involved simplicity of its design and the efficient use of the wood, which affords them a low production cost and a relatively low weight; they can additionally be easily transported and installed in the course of the construction of an immovable property.  
         [0036]     The panels ( 1 ) of the present invention permit to build immovable properties with a great flexibility, inasmuch as panels ( 1 ) of different dimensions can be manufactured without any problem, consistently with the requirement of the different types of immovable properties. At the same time, said panels could be factory made with windows or other cavities each specific property may require.  
         [0037]     On the other hand, panels ( 1 ) of the invention also serve for the construction of walls, floors, covers and roof structures and do not require beams or sidings, because their collaborating system permits so solve without problems the difference distances and clearances between the diverse walls or pillars, and where the geometry of each of the means forming the panel ( 1 ) is finally adapted to the structural and/or functional requirements of each case, a feature that permits an efficient use of the wood and the other involved materials.  
         [0038]     In order to join two adjacent wooden panels ( 1 ) during the construction of an building, it suffices to weld the metal plates ( 9   a ) or metal profiles ( 9   b ) of the first stress transmitting means ( 9 ) found in the ends of said wooden panels ( 1 ). Other joint means can be alternatively used, without the essence of the invention varies.  
         [0039]     An additional and very attractive characteristic of panels ( 1 ) of the present invention is the possibility of placing additional insulating means between the cavities that can be eventually produced between two consecutive reinforcement means ( 10 ). On the other hand, the face of the panels presenting the above mentioned cavities can be subsequently lined with concrete, which permits a better quality of the related building. In case a concrete lining is applied, it is recommended to use a metal mesh in order to reinforce the structure associated to said concrete lining.  
         [0040]     The fact is emphasized that the manufacture and installation of the invention panels ( 1 ) do not require the use of nails, screws or adhesives, nor any type of labor-intensive unions, whereby the construction of real estate projects involving this type of panels is remarkably faster than the alternatives existing in the previous art. Furthermore, the fact should be underscored that the manufacture and installation is of a dry character.  
         [0041]     The disclosed invention permits to reach outstanding results, which combine an efficient use of the wood and the industrial and large-scale manufacture of prefabricated structural wooden panels; they can subsequently be transported and installed in a simple, fast and economic way, which can excellently satisfy the requirements of structural strength, thermal insulation, acoustic insulation and durability of a real estate project.  
       DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION  
       [0042]     The preferred embodiment of the invention contemplates the following specifications:  
         [0043]     a. The wooden panel ( 1 ) corresponds to the wall of a building and its measures are 2.4 m high by 3.0 m wide.  
         [0044]     b. The first elongated wooden means ( 2 ) are manufactured from standard dimensions wood pieces, having a rectangular cross section of 2″ (50.8 mm) by 3″ (76.2 mm), where one of its longer sides is arranged parallel to the main plane of the panel.  
         [0045]     c. The cross-section of the male ( 3 ) and female ( 4 ) faces of the first elongated wooden means ( 2 ) has an arrow point geometry when the involved adjacent means are two of said first elongated wooden means ( 2 ), and it has a flat geometry when the face of the corresponding first elongated wooden means ( 2 ) corresponds to one of the extreme faces of the wooden panel ( 1 ) or when one of said first elongated wooden means ( 2 ) is in contact with one of the elongated reinforcement means ( 10 ).  
         [0046]     d. The first passing through holes ( 5 ) correspond to six horizontal through perforations being equidistant to each other.  
         [0047]     e. The first tensioning means ( 7 ) correspond to six steel wires, cables or bars being stressed in their elastic range to a stress equal to or lower than 75% of their flow stress.  
         [0048]     f. The pairs of first stress transmitting means ( 9 ) correspond to six pairs of metallic profile pieces having an “L”-shaped cross-section, which are supported by means of one of their faces on the extreme faces of said first elongated wooden means ( 2 ), located at the ends of said wooden panel ( 1 ) and joined by means of welding to the first tensioning means ( 7 ); the other face of said “L”-shaped metal profiles ( 9   b ) is supported on the side of the wooden panel ( 1 ).  
         [0049]     g. The elongated strengthening means ( 10 ) are manufactured with standard dimension wood pieces, having a rectangular 2″ (50.8 mm) by 4″ (101.6 mm) rectangular cross-section, where one of its shorter sides is arranged parallel to the main plane of panel ( 1 ) and they have faces ( 11 ) and first perforations ( 12 ) coinciding with those of the first elongated wooden means ( 2 ).  
         [0050]     h. Each of said first elongated wooden means ( 2 ) is formed by one or more pieces of wood which are correspondingly joined one next to the other until they reach the full length of panel ( 1 ).  
         [0051]     i. The series of first elongated wooden means ( 2 ) is made of dry and treated wood. 
     
    
     DESCRIPTION OF THE FIGURES  
       [0052]      FIG. 1  shows a front view of an embodiment of the prefabricated structural wooden panel ( 1 ) of the invention.  
         [0053]      FIG. 2  illustrates an elevation view of an embodiment of the prefabricated structural wooden panel ( 1 ), where the elongated reinforcement means ( 10 ) are made of wood.  
         [0054]      FIG. 3  shows an elevation view of an embodiment of the prefabricated structural wooden panel ( 1 ), where the elongated reinforcement means ( 10 ) are made of wood reinforced with metal.  
         [0055]      FIG. 4  is a view in perspective of the structural wooden panel ( 1 ) during its assembly process.  
         [0056]      FIG. 5  illustrates in greater detail the elevation view shown in  FIG. 2 .  
         [0057]      FIG. 6  describes an elevation view of an embodiment of the prefabricated structural wooden panel ( 1 ) having a double-wall configuration.  
         [0058]      FIG. 7  shows an elevation view of an embodiment of the prefabricated structural wooden panel ( 1 ), where the elongated reinforcement means ( 10 ) are made of metal-reinforced wood in both of its lateral faces.  
         [0059]      FIG. 8  illustrates an elevation view of an embodiment of the prefabricated structural wooden panel ( 1 ), where the elongated reinforcement means ( 10 ) are made of metal-reinforced wood in one of their lateral faces.  
         [0060]      FIGS. 9 and 10  respectively show an elevation and a detailed view of the arrangement of two consecutive panels ( 1 ), according to an embodiment of the invention.  
         [0061]      FIGS. 11 and 12  respectively illustrate and elevation and a detailed view of the description in  FIG. 7 .