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CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     Benefit of U.S. Provisional Applications for Patent Ser. No. 60/700,723, filed on Jul. 20, 2005, and Ser. No. 60/733,171, filed on Nov. 4, 2005, is hereby claimed.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to a wall building construction unit and methods and is more particularly concerned with a prefabricated insulated and stackable element.  
       BACKGROUND OF THE INVENTION  
       [0003]     It is well known in the art to build wooden frameworks for housing walls. An insulating core is then usually inserted in-between the studs and lintels or headers and closed with facing panels. This standard operation can be time consuming and have considerable effects in areas where the residential building period is constrained to a few months of the year due to for example a harsh winter climate.  
         [0004]     Numerous construction elements have been proposed for wall construction such as in the following documents: 
        U.S. Pat. No. 2,902,733 granted to Justus on Sep. 8, 1959 for a “Corner Construction for Sawed Timber Walls”;     U.S. Pat. No. 3,552,079 granted to Mortensen on Jan. 5, 1971 for a “Laminated Tongue and Groove Building Element”;     U.S. Pat. No. 3,742,665 granted to Henry et al. on Jul. 3, 1973 for a “Modular Building Construction”;     U.S. Pat. No. 4,344,263 granted to Farmont on Aug. 17, 1982 for a Building Log with High Thermal Insulation Characteristics”;     U.S. Pat. No. 4,503,648 granted to Mahaffey on Mar. 12, 1985 for a “Lightweight Composite Building Module”;     U.S. Pat. No. 4,614,071 granted to Sams et al. on Sep. 30, 1986 for “Building Blocks”;     U.S. Pat. No. 4,937,122 granted to Talbert on Jun. 26, 1990 for an “Insulated Construction Element”; and     U.S. Pat. No. 6,000,177 granted to Davidson on Dec. 14, 1999 for a “Building Structure Having the Appearance of a Log Structure”.        
 
         [0013]     All the above lack either a provision for an insulated section in the stacking panel; a prefabricated insulated element; or passageways for a conventional approved wooden stud, approved and even required by most territorial or state building codes, forming a self-supporting wall structure, especially for external walls (thereby putting the load-bearing constraints on the stacking wall sections which is not regulated or preferred in building construction).  
         [0014]     Accordingly, there is a need for an improved log, member or unit for wall construction with a simple configuration.  
       SUMMARY OF THE INVENTION  
       [0015]     It is therefore a general object of the present invention to provide an improved unit for wall construction.  
         [0016]     An advantage of the present invention is that the unit for wall construction is insulated and can be easily mounted on a stud structure which provides the structural support approved for load-bearings under construction codes.  
         [0017]     Another advantage of the present invention is that the unit for wall construction is prefabricated at another location than the wall construction site.  
         [0018]     A further advantage of the present invention is that the units for wall construction being relatively lightweight, can be quickly stacked on one another.  
         [0019]     Yet another advantage of the present invention is that the unit for wall construction enables fast construction of rigid insulated walls which can eventually be disassembled and reassembled at another location.  
         [0020]     Still another advantage of the present invention is that the unit for wall construction provides for sidewalls which naturally oppose warping when each of said sidewalls is made of multiple wood members.  
         [0021]     Another advantage of the present invention is that the unit for wall construction includes stud longitudinal sections extending into through openings and secured to the unit, the stud longitudinal sections being used to support the structural transversal, typically vertical, loads transmitted through the wall structure.  
         [0022]     A further advantage of the present invention is that the unit for wall construction has wall studs extending there through that are spaced from the side wooden planks for increased insulation between the two side planks.  
         [0023]     According to an aspect of the present invention, there is provided a stackable unit for wall construction for cooperation with wall stud members forming a self-supporting wall structure, the unit comprising: first and second opposed elongate side wooden planks secured to one another with an insulating layer bonded thereto, the insulating layer having a plurality of through openings spaced from one another and extending transversely therethrough for receiving a longitudinal section of respective said stud member.  
         [0024]     In one embodiment, respective said stud longitudinal section is permanently secured to the unit when inserted into corresponding said through opening, each said stud longitudinal section being adapted to structurally connect to at least one corresponding said stud longitudinal section of an adjacent said unit via a securing member for forming the self-supporting wall structure and having structural loads transmitted therethrough.  
         [0025]     Typically, each said stud longitudinal section is adapted to be in abutting engagement with and securable to at least one corresponding said stud longitudinal section of an adjacent said unit.  
         [0026]     Conveniently, each said stud longitudinal section has a through hole extending longitudinally therealong for slidably receiving the securing member therethrough for connection with said at least one corresponding said stud longitudinal section of an adjacent said unit.  
         [0027]     Conveniently, each said securing member forces corresponding said stud longitudinal section to be in abutting engagement with said at least one corresponding said stud longitudinal section of an adjacent said unit.  
         [0028]     Conveniently, the securing member is a screw-nut fastener for clamping corresponding said stud longitudinal section in abutting engagement with said at least one corresponding said stud longitudinal section of an adjacent said unit. Conveniently, each said securing member is a screw screwably extending through corresponding said stud longitudinal section and screwing into said at least one corresponding said stud longitudinal section of an adjacent said unit to be in secured abutting engagement therewith.  
         [0029]     Alternatively, each said stud longitudinal section has a protrusion member extending longitudinally outwardly from a first end thereof and a cavity member extending longitudinally inwardly into an opposed second end thereof, said protrusion member being adapted to engage corresponding said cavity member of a stud longitudinal section of a first adjacent said unit, and said cavity member being adapted to receive corresponding said protrusion member of a stud longitudinal section of a second adjacent said unit. Typically, the first and second side planks being adapted to stack over a subjacent unit.  
         [0030]     According to another aspect of the present invention there is provided a method of constructing a wall composed of prefabricated stackable wall units, the method comprising the steps of: mounting a first of said units on a sole plate and securing said stud longitudinal section thereof onto the sole plate using securing members and bonding therebetween; and assembling a plurality of said units on top of one another in a stack with securing each said stud longitudinal section to respective said stud longitudinal section of a subjacent said unit using said securing members and bonding therebetween.  
         [0031]     Alternatively, the method could comprise the steps of: assembling a plurality of said units on top of one another in a stack with securing each said stud longitudinal section to respective said stud longitudinal section of a subjacent said unit using said securing members and bonding therebetween; mounting the units on a sole plate; and securing the units together and to the sole plate using securing members to longitudinally clamp registered said stud longitudinal sections to each adjacent ones and to the sole plate.  
         [0032]     In one embodiment, the through openings slidably receive respective said stud longitudinal section therethrough.  
         [0033]     Each wooden plank comprises a plurality of individual planks and such individual planks may conveniently be formed with a tongue and groove interlocking arrangement along respective longitudinal edges thereof.  
         [0034]     Moreover, each wooden plank may advantageously be provided with a recess on the top and the bottom thereof for accommodating other building elements such as a sill or sole plate at the bottom or a lintel or top plate at the top.  
         [0035]     Each wooden plank is provided at its ends with a recess for receiving part of a wall stud, typically half the width of the stud whereby wooden planks sitting end to end can accommodate and embrace the complete stud to its full dimension.  
         [0036]     The stackable unit of the present invention may advantageously be provided with a plurality of planks in the form of logs and successive planks are disposed in such manner as to ensure that the heartwood in each is offset from the heartwood of an adjacent plank thereby to reduce the risk of warping or twisting with age.  
         [0037]     According to another aspect of the present invention there is provided a method of constructing a wall composed of prefabricated stackable wall units, the method comprising the steps of erecting a wood frame including vertical studs upstanding from a sill or sole plate, prefabricating stackable units for wall construction of the kind defined by the first aspect of the invention, feeding such units over the studs thereby to accommodate the studs within the through openings formed in the units, and bonding adjacent units together to produce a unitary wall structure around the studs.  
         [0038]     In an alternative method the prefabricated stackable units for wall construction are assembled one on top of another with suitable bonding therebetween and mounted on a sill or sole plate, and vertical studs are then inserted into the openings and affixed.  
         [0039]     Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0040]     Further aspects and advantages of the present invention will become better understood with reference to the description in association with the following Figures, wherein:  
         [0041]      FIG. 1  is a top perspective view of an embodiment of a unit for wall construction in accordance with the present invention showing units in the process of being stacked on a stud structure to form a wall construction;  
         [0042]      FIG. 2  is an enlarged perspective view of one embodiment of  FIG. 1  without studs;  
         [0043]      FIG. 2   a  is a view similar to  FIG. 2 , showing another embodiment of the unit with structural stud longitudinal sections permanently secured thereto;  
         [0044]      FIG. 2   b  is a view similar to  FIG. 2   a , showing another embodiment with stud sections having through hole extending therethrough;  
         [0045]      FIG. 3  is a left section view of the embodiment taken along line  3 - 3  of  FIG. 2 ; and  
         [0046]      FIG. 3   a  is a view similar to  FIG. 3 , showing two units of the embodiment of  FIG. 2   a  secured to each other via screws;  
         [0047]      FIG. 3   b  is a view similar to  FIG. 3   a , partially broken, showing a plurality units of the embodiment of  FIG. 2   b  secured to each other via a screw-nut fastener;  
         [0048]      FIG. 4  is a simplified top view of the embodiment of  FIG. 1  showing partially two units without studs; and  
         [0049]      FIG. 4   a  is a view similar to  FIG. 4 , showing the insulating core spacing the stud from the wooden sides. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]     With reference to the annexed drawings the preferred embodiments of the present invention will be herein described for indicative purpose and by no means as of limitation.  
         [0051]     Referring to  FIG. 1 , there is shown an embodiment of a wall construction unit  10  in accordance with the present invention. The preferably rectangular and generally longitudinal unit  10  comprises mainly a pair of wooden planks, typically engineered wooden planks (EWP), generally flat timber, assembled side planks  20 ,  22  or the like sandwiching a heat insulating core  50  or layer made of urethane, polyurethane, foamable plastic polymer or the like. The height H of each wall construction unit  10  is typically of approximately twelve (12) inches or one (1) foot, whilst the length is generally of a multiple of sixteen (16) or twenty-four (24) inches, or typically of up to approximately height (8) or twelve (12) feet. The width of each assembled plank  20 ,  22  is of approximately one (1) inch whilst the width W of the insulating core  50  is of about 3.5 inches to be used conveniently with notional two-by-four (2×4) studs  14  as it will be clearly explained hereinafter. Alternatively, the width W of the insulating core could be of 5.5 inches to be used conveniently with notional two-by-six (2×6) studs.  
         [0052]     In territories such as Canada and most States of the United States, construction building codes require a (wooden) wall frame structure to respect certain standards for load-bearing requirements. Notional two-by-four studs  14  can be used with respect to these above-mentioned standards with certain criteria. One of those criteria is the generally horizontal spacing S between the two-by-four or vertical structural studs  14 . In  FIG. 1 , the spacing S is understood to respect those construction building codes and are generally of, for example, twelve (12) or sixteen (16) inches.  
         [0053]     As shown in FIGS.  2  and/or  3 , each of the EWP or assembled side plank  20 ,  22  is preferably manufactured by a series of wooden planks  24 . Generally vertically, one or a series of intermediate upper grooves  26  are carved on the upper part of each wooden plank  24  to fit or nest with one or a series of intermediate lower tongues  28  carved on the lower part of also each wooden plank  24 , except for the ends of the wooden planks  24  forming the ends of the assembled plank  20 ,  22 . Furthermore, each successive wooden plank  24  typically provides for a different grain orientation as indicated by the numeral  30 . As one skilled in the art will understand, any piece of cut wood works over time, or, expressed differently, grain orientation affects the straightness or alignment of the wooden plank  24 , and thereby of the assembled planks  20 ,  22  over time. A spiral distortion along the grain creates warping or twisting with ageing of the wood, and this towards the heartwood, represented by the numeral  32 . The heartwood  32  of each consecutive wooden plank  24 , or the position on the wooden plank  24  where the heartwood would be, is therefore preferably positioned alternatively on the left and then on the right from an approximate vertical reference or axial line L (shown in  FIG. 3 ). The assembled plank  20 ,  22  is thereby prevented from a strong natural warping tendency towards either side.  
         [0054]     Generally vertically, an upper groove  34  is carved on the upper end of the assembled plank  20 ,  22  to fit or nest with a lower tongue  36  carved on the lower end of another of the same assembled plank  20 ,  22 . Also generally vertically, the amount of insulating core  50  in each unit  10  is such that if two units  10  are positioned one above another, or stacked, there is infinitesimal spacing (not shown) between the two insulating core  50  sections, except for those destined to be lowermost and uppermost insulating core sections  50  of the wall to be constructed. Understandingly, such design of the height H of the insulating core  50  offers the wall to be constructed a thermal insulation across its entire vertical height. As shown in  FIG. 1  for a lowermost unit  10  example, the numeral  52  represents a longitudinal void or recess of insulating material adjacent the insulating core  50  for the section of the lowermost (or uppermost) wall construction unit  10  destined to be mounted adjacent a bottom plate  16  (or a top plate, header or lintel not shown), as will be explained further below.  
         [0055]     In the longitudinal direction and as shown in the  FIGS. 1 and 2  and more specifically in  FIG. 4 , at each longitudinal end of the unit  10 , a recess  54  is left between the insulating core  50  and the adjacent assembled planks  20 ,  22 . The thickness T of the recess  54  is preferably of about half the thickness 2T of the generally vertical component used for structural load-bearing walls, i.e. generally two-by-four studs  14 , or three-quarter of an inch (0.75 inch). A void  56  or through opening also of thickness 2T is made in the unit  10  preferably at each equal interval of spacing S. The width W of the void  56  is preferably the same as the width of the insulating core  50 . The studs  14  are preferably insulated studs  14  so as to offer thermal insulation across the entire length of the wall to be constructed. Alternatively and in the event wherein the studs  14  to be used are not insulated, the insulating core  50  of the unit  10  could have a larger width (as shown in  FIG. 4   a ) than the width W of the void  56  with two opposed insulating bands  51  spacing the studs  14  from the corresponding plank  20 ,  22 , each insulating band being adjacent the void  56  and one of the assembled planks  20  or  22  so as also to offer thermal insulation across the entire length (and height) of the wall to be constructed.  
         [0056]     The manufacturing operation of the unit  10  is generally and advantageously performed at another location than where the wall is to be constructed. Assembling the wooden planks  24  to form the assembled plank  20 ,  22  may leave infinitely small openings (not shown) between said wooden planks  24 . The insulating material used for the insulating core  50  has such properties that it infiltrates such openings if they are present to ensure an airtight unit  10 . In the event wherein some insulating material exits on the exterior surface of the assembled plank  20 ,  22 , shaving or cleaning said insulating material is performed easily. Advantageously, the outer grooves  38  and/or exterior finishing of the assembled planks  20 ,  22  of the wall construction unit  10  are generally machined if desired during the same or in a subsequent manufacturing step. Preferably, a series of units  10  is brought to the wall construction site once each unit  10  has been completely assembled.  
         [0057]     Generally, the structural load-bearing studs  14  for wall construction are mounted vertically on the generally horizontal bottom plate  16 . A joining set retarding and expanding epoxy substance, glue, adhesive, resin, foam or the like (not shown) is layered on the upper part of the bottom or sole plate  16 . The first wall construction unit  10  comprising the lowermost void  52  is positioned above the structural studs  14  with the voids  56  and recesses  54  vertically aligned with the studs  14 . The unit  10  is then lowered down towards the bottom plate  16  as per the general direction indicated by arrows A shown in  FIG. 1 . A coating of epoxy substance is then layered on the upper part of the installed unit  10  and another unit  10  is positioned above the structural studs  14  with again the voids  56  and recesses  54  vertically aligned with the studs  14 , and then again the uninstalled unit  10  is lowered down for stacking on and above the initially installed unit  10 , and so on.  
         [0058]     Once the wall is assembled as previously described, the set retarding and expanding epoxy has generally the effect of completely filling and sealing the voids and minimal openings (not shown) between the stacked units  10 , and between the unit  10  and the bottom plate  16  or top plate, header or lintel. It may be necessary to shave or clean the dried epoxy that would be apparent from the exterior of the wall. An appropriate epoxy retarding time is approximately between 10 and 30 minutes. Obviously, doors and windows (not shown) are usually present in this type of construction. Since said doors and windows are usually positioned at standard spacing intervals, to follow the appropriate spacing for the structural studs  14 , the assembly of the units  10  is not adversely affected apart from requiring an appropriate shortening or cutting in some instances, which is standard in the construction industry and not adversely time-consuming. Finally, this example is presented with the structural studs  14  present before the units  10  are stacked one onto the other, but the operations could be reversed, with the studs inserted once the units are positioned stacked onto one another, without departing from the scope of the present invention.  
         [0059]     As shown in  FIG. 2   a , in another embodiment of the present invention, each unit  10 ′ has its voids  56 ′ filled with stud longitudinal sections  14 ′ permanently secured to the unit  10 ′ via bonding or the like when inserted thereinto. Each stud longitudinal section  14 ′ is adapted to structurally connect to at least one stud longitudinal section  14 ′ of an adjacent unit  10 ′ via a securing member  60 , typically a screw  60   a  (see  FIG. 3   a ) that screwably extends through the stud section  14 ′ and is partially screwable into the stud section  14 ′ of a subjacent unit  10 ′, to form the self-supporting wall structure and have transversal structural loads, typically vertical, transmitted therethrough. Typically, each stud section  14 ′ is in abutting engagement with the subjacent stud section  14 ′ or the load support. With this type of securing member  60   a , the lower unit  10 ′ is first secured to the sole plate  16  and then subsequent units  10 ′ are stacked over and secured to the subjacent one, with all the stud sections  14 ′ forming the structural load path of the wall structure.  
         [0060]     Alternatively, as shown in  FIGS. 2   b  and  3   b , each stud section  14 ′ has a through hole  62  extending longitudinally therealong for slidably receiving a screw-nut fastener  60   b  or the like therethrough for connection with the other stud section  14 ′ in register therewith.  
         [0061]     The screw-nut fastener  60   b  clamps all the corresponding stud sections in abutting engagement with each other and to the subjacent sole plate  16  or the like and typically a corresponding top plate (not shown). The screw-nut fastener  60   b  typically includes an elongate rod  64  having a threaded free end that screwably receives a nut  66  and washer  68 . The head  70  of the rod  64 , or a hidden nut (not shown), is typically locked to the lower plate  16  (see  FIG. 3   b ).  
         [0062]     With this securing member  60   b , all units  10 ′ are assembled over each other before they are secured to each other ant to the lower plate  16  and typically the upper plate (not shown) with all stud sections  14 ′ abutting adjacent ones to form the structural load path of the wall structure.  
         [0063]     As schematically shown in dotted lines in  FIG. 3   b , each stud section  14 ′ could have a protrusion member  80 , such as a tongue or the like, extending longitudinally outwardly from a first end thereof and a cavity member  82 , such as a groove or the like, extending longitudinally inwardly into an opposed second end thereof. The protrusion member  80  is adapted to engage a corresponding cavity member  82  of an adjacent stud section  14 ′ as an additional securing means as well as a longitudinal guiding alignment means between two adjacent units  10 ′ when being assembled to one another.  
         [0064]     Although the present invention has been described with a certain degree of particularity, it is to be understood that the disclosure has been made by way of example only and that the present invention is not limited to the features of the embodiments described and illustrated herein, but includes all variations and modifications within the scope and spirit of the invention as hereinafter claimed.

Summary:
A stackable insulated unit for wall construction for cooperation with conventional wall studs forming a self-supporting wall structure consists of two side wooden planks spaced apart and provided therebetween with an insulating layer which has at least two transverse through openings for reception of respective wall stud sections, either slidably or permanently secured thereto.