Abstract:
A method for manufacturing fabricated wooden studs including: providing (a) face-sheets of OSB, the face-sheets having opposite ends, (b) edge-strips of OSB, and (c) end-members; placing a first one of the face-sheets on an assembly base; placing a plurality of edge-strips onto the first face-sheet, the edge-strips being in spaced, parallel relationship to one another; placing a plurality of end-members on the first face-sheet at the opposite ends and between adjacent edge-strips; placing a second of the face-sheets onto all of the placed edge strips and placed end-members to sandwich such edge-strips and end-members between the first and second face-sheets; applying adhesive between the layers at any time during the placing steps, thereby to form a three-layer assembly; pressing the three-layer assembly until the adhesive is set to produce a stud assembly; and cutting the stud assembly along lines which divide the edge-strips to form a plurality of studs.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to wooden studs for construction purposes and, more specifically, to methods for manufacturing studs.  
         BACKGROUND OF THE INVENTION  
         [0002]    Wood frame construction is a very common type of building construction technology used today. In the continual quest to reduce the cost of construction and to increase the productivity of the construction labor force, attention is given to reducing the cost of material, reducing the labor required for construction, and increasing the quality of the material used.  
           [0003]    One nearly ubiquitous structural element used in wood construction is a piece of lumber called a stud. Studs are the vertical, load-bearing pieces of wood in the interior or exterior walls of a building to which sheathing or panel material is attached to form the wall structures. In addition to their use in wall construction, studs are also used in other parts of the framing process. There is a need to provide a reliable, low-cost supply of high-quality wooden studs for the construction industry.  
           [0004]    The traditional stud is made in one piece and cut from tall trees, into 1½ inch by 3½ inch cross-sections (the standard 2×4), or 1½ inch by 5½ inch cross-sections (the standard 2×6), and milled into various lengths—most typically 8 or 9 feet. Such studs are often subject to warping, both bending and twisting.  
           [0005]    Among the many factors which contribute to the cost and quality of wooden studs are the following: (1) the cost of the raw material used, affected by the amount and quality of timber available and the demand for timber; (2) the cost of manufacture of the studs; (3) the cost of transportation, which, among other things, is dependent on the weight of the studs; (4) the resistance to warpage of the studs, which reduces waste and increases the quality of the resulting structures; and (5) ease of use of the studs, affected by weight and by the extent of warpage. Thus, the need for a reliable, low-cost supply of high-quality wooden studs can be translated into a need for straight, stable, lightweight studs made from a source of inexpensive raw material.  
           [0006]    One source of inexpensive raw material used in the construction industry is oriented strand board (OSB), a dimensionally-stable engineered wood sheet product which utilizes the fiber available from “waste” trees which are too small to produce traditional solid-wood products such as studs. The raw material for OSB itself, therefore, is inexpensive, and the manufacturing process is highly automated, making OSB an excellent, cost-effective source of raw material for fabricated lumber.  
           [0007]    OSB has been used in the past as part of fabricated structural members for applications such as trusses, joists, rafters, and girders, i.e., in applications in which it is necessary for a horizontal structural member to carry vertical loads across the horizontal span of the structural member. Such beams, typically in I-beam or box-beam configurations, were structures to which engineered sheet materials could be applied because of the fact that I-beam and box-beam cross-sections are efficient in withstanding the tensile and compressive loads present in such applications, not to mention the fact that timber for long-span structural members is often not readily available.  
           [0008]    However, the concept of engineered structures and in particular hollow box structures has not been widely accepted with respect to studs, i.e., 2×4 and 2×6 structures for use as studs in supporting interior and exterior walls. There are several reasons for this. First, it tends to be counterintuitive to make wooden studs hollow since studs are relatively slender. Second, since studs are designed to receive and to secure fasteners such as nails, it is thought that a hollow stud would not secure the appropriate fasteners as readily as solid wood. Third, studs are sized for placement in vertical, upright positions where they carry mainly compressive forces. Thus, box-shaped designs have not typically been associated with wooden studs.  
           [0009]    In the past, there have been a number of efforts directed to the manufacture of engineered wooden beams, primarily for horizontal beam applications, with very little effort of practical consequence being applied with respect to the manufacture of studs intended primarily to take compressive loads. In fact, essentially no engineered wooden studs, whether or not made primarily of OSB, are available in normal market channels. Furthermore, the configuration of fabricated beam structures and other structures that may be seen in prior art documents are quite complex, and thus would typically be relatively expensive to manufacture.  
           [0010]    There has been a need for a simple, low-cost, stable compressive-load-bearing wooden stud which can be easily manufactured and easily used.  
         OBJECTS OF THE INVENTION  
         [0011]    Accordingly, it is a principal object of the invention to provide a fabricated wooden stud made primarily of OSB, thereby using wood sources not able to be used for solid timber studs.  
           [0012]    A more specific object of the invention to provide a manufacturing method for a fabricated wooden stud made primarily of OSB.  
           [0013]    It is another object of the invention to provide an improved stud which can be produced at a minimum cost.  
           [0014]    It is object of the invention to provide an efficient manufacturing method for a fabricated wooden stud.  
           [0015]    Another object of this invention is to provide an improved wooden stud having high structural strength without using solid timber.  
           [0016]    Another object of this invention is to provide an improved stud that is not subject to the warping that is often typical of traditional construction lumber.  
           [0017]    Another object of this invention is to provide a manufacturing method which utilizes standard sheets of OSB to construct fabricated wooden studs.  
           [0018]    Another object of this invention is to provide a stud that has lower weight, thereby lowering transportation costs and facilitating use on construction sites.  
           [0019]    Yet another object of this invention is to provide a fabricated stud which has the ability to receive framing nails and other fasteners used in wooden building construction.  
           [0020]    Another object of this invention is to provide a manufacturing method for fabricated wooden studs which is highly automated, requiring a minimal amount of manual intervention.  
           [0021]    These and other objects of the invention will be apparent from the following descriptions and from the drawings.  
         SUMMARY OF THE INVENTION  
         [0022]    The instant invention is a method for fabricating wooden studs, each of which, broadly described, has the following characteristics: (1) a pair of fully-aligned face-members of OSB spaced from one another and each having first and second ends and first and second elongate edges; (2) first and second fully-aligned edge-members of OSB spaced from one another, the first and second edge-members being adhesively affixed between the face-members along the first edges and second edges thereof, respectively; and (3) a pair of end-members adhesively affixed between the face-members at the ends thereof. Such fabricated wooden stud, preferably made using the method of this invention, is the subject of a concurrently filed patent application, Ser. No. ______, of the same inventor, entitled “Fabricated OSB Stud.” 
           [0023]    The manufacturing method of this invention overcomes the above-noted problems and shortcomings, satisfies the objects of the invention, and produces highly desirable fabricated wooden studs. In describing the method of this invention, certain terminology is used which is defined at the end of this summary section.  
           [0024]    The method for manufacturing fabricated wooden studs includes: (1) providing a supply of face-sheets of OSB, the face-sheets having opposite ends; (2) providing a supply of edge-strips of OSB; (3) providing a supply of end-members; (4) placing a first one of the face-sheets on an assembly base; (5) placing a plurality of edge-strips onto the first face-sheet, with the edge-strips positioned in spaced, parallel relationship to one another; (6) placing a plurality of end-members on the first face-sheet at the opposite ends and between adjacent edge-strips; (7) placing a second of the face-sheets onto all of the placed edge strips and placed end-members to sandwich such edge-strips and end-members between the first and second face-sheets; (8) applying adhesive between the layers at any time during the placing steps, thereby to form a three-layer assembly; (9) pressing the three-layer assembly until the adhesive is set to produce a stud assembly; and (10) cutting the stud assembly along lines which divide the edge-strips to form a plurality of studs.  
           [0025]    In a preferred embodiment of the invention, the method further includes providing a supply of inner-sheets of OSB and cutting the inner-sheets of OSB to create the supply of edge-strips.  
           [0026]    In another preferred embodiment of the inventive method, providing the supply of end-members includes cutting the end-members from at least one of the inner-sheets.  
           [0027]    In certain preferred embodiments of the invention, the method further includes the steps of (1) providing a supply of core-members; (2) placing a plurality of core-members onto the first face-sheet between the adjacent edge-strips; and (3) applying adhesive to the plurality of core-members. In some other preferred embodiments, a plurality of core-members are placed in spaced relationship with each other between each adjacent pair of the edge-strips.  
           [0028]    Other preferred embodiments of the inventive method include the steps of (1) cutting wiring pass-throughs in the first and second face-sheets; and (2) cutting wiring pass-throughs in the core-members.  
           [0029]    In a highly preferred embodiment of the invention, the end-members and the core-members are cut from the supply of inner-sheets of OSB. In such embodiments, wiring pass-throughs are cut in the inner-sheets at locations from which the core-members are cut.  
           [0030]    In another highly preferred embodiment of the inventive manufacturing method, the pressing step includes pressing a stacked plurality of three-layer assemblies.  
           [0031]    Additionally, highly preferred embodiments of the method include trimming the ends of the stud assembly prior to cutting the stud assembly into a plurality of studs.  
           [0032]    The intended meanings of various terms used in this document are set forth in the paragraphs which follow:  
           [0033]    The term “face-member” as used herein refers to each of the two wider elongate pieces which, in preferred embodiments of this invention, form all of the wide sides of the stud. In similar fashion, the term “edge-member” as used herein refers to each of the two narrower pieces which, in preferred embodiments of this invention, form part of the narrow sides of the stud.  
           [0034]    The term “fully-aligned” is used herein with respect to the two face-members or with respect to the two edge-members. The term describes two members as being sized and oriented with respect to each other in certain ways, namely: (1) the two members have substantially equal dimensions of length, width, and thickness; (2) the length directions of the two members are substantially parallel; and (3) perpendicular projections of the two members onto a plane that is perpendicular to either the thickness or width directions of the members (but not both) are fully overlapping.  
           [0035]    The term “end-member” as used herein refers to the two pieces each of which occupies the space inside the stud at an end thereof, such space being formed between the two face-members and the two edge-members.  
           [0036]    The term “core-member” as used herein refers to each piece which is similar to an end-member but which occupies a space inside the stud at a selected location away from the ends of the stud, such spaces being formed by the two face-members and the two edge-members.  
           [0037]    The term “OSB plane” as used herein with respect to a particular OSB member refers, to the plane of the top surface of the sheet of OSB from which the particular member has been cut. For example, if several sheets of OSB material are layered one on top of another, their OSB planes are parallel regardless of the width and length directions of the OSB sheets from which they have been cut.  
           [0038]    The term “face-sheet” as used herein with respect to a method of manufacture, refers to each of the top and bottom OSB layers of the stud assembly.  
           [0039]    The term “edge-strip” as used herein with respect to a method of manufacture, refers to each of the plurality of elongate OSB pieces which are part of the stud assembly and which, when the stud assembly is cut into a plurality of studs, form the edge-members of the studs.  
           [0040]    The term “inner sheet” as used herein with respect to a method of manufacture, refers to the sheets of OSB from which edge-strips, end-members, and core-members are cut.  
           [0041]    The term “stud assembly” as used herein with respect to a method of manufacture, refers to the three-layer sandwich which includes first and second face-sheets with a plurality of edge-strips, end-members, and core-members arranged in accordance with a plan accommodating the stud configuration and the subsequent cutting of the sandwich into a plurality of studs. (See FIG. 3, referred to below.) The term “assembly base” as used herein refers to a preferably horizontal work surface on which the face-sheets and the various members to be sandwiched therebetween are laid up during the stud fabrication process.  
           [0042]    The words “the entire stud is made of OSB” should be understood to allow the use of adhesive to bond the various parts of the fabricated stud together and also to include the optional use of various coatings on the studs, such as a water-repellant coating over the edges of the OSB material.  
           [0043]    The term “broken corners” as used herein with respect to a stud refers to the outer corners along the length of the stud as having been trimmed to have a small radius or slightly beveled character in order to eliminate sharp corners.  
           [0044]    The term “wiring pass-throughs” as used herein refers to holes through the smallest dimension of the stud to allow electrical wiring to be installed easily in walls constructed with such fabricated wooden studs. Wiring pass-throughs in a series of studs forming a wall allow rapid wiring on the job site. The term is used herein to refer both to holes in individual members of the stud (during manufacturing) as well as to holes through the finished stud. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0045]    [0045]FIG. 1 is a partial perspective drawing of an end portion of the fabricated wooden stud.  
         [0046]    [0046]FIG. 2 a ,  2   b , and  2   c  are the three orthographic views of the fabricated wooden stud, with the stud broken at a point along the length of the stud in order to show both ends of the stud. FIG. 2 a  is the face view; FIG. 2 b  is the edge view; and FIG. 2 c  is the end view.  
         [0047]    [0047]FIG. 3 is a cutaway schematic which illustrates a simple approach to manufacturing the fabricated wooden stud.  
         [0048]    [0048]FIGS. 4 a  and  4   b  are partial end-view schematics of one corner of the fabricated wooden stud.  
         [0049]    [0049]FIG. 5 is a partial cutaway perspective drawing of a end portion of an embodiment of the fabricated wooden stud which includes insulation in the void space which is formed by the spaced face-members and the spaced edge-members.  
         [0050]    [0050]FIGS. 6 a  and  6   b  are schematic diagrams of a preferred embodiment of a production line which utilizes the inventive method claimed herein to manufacture fabricated OSB studs. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0051]    [0051]FIGS. 1 through 5 assist in description of a preferred embodiment of the fabricated wooden stud produced by the inventive manufacturing method. FIG. 1 shows a perspective drawing of an end portion of fabricated wooden stud  10 , illustrating the general configuration of the stud.  
         [0052]    [0052]FIGS. 2 a - 2   c , which are a set of orthographic views of the fabricated wooden stud, illustrate more clearly the complete structure of a highly preferred embodiment of stud  10 . Edge-members  22  are sandwiched between and adhesively bonded to two face-members  20 . A pair of end-members  24  are also sandwiched between and adhesively bonded to two face-members  20 . Face-members  20  are fully-aligned, as are edge-members  22 . Edge-members  22  are positioned such that elongate outer surfaces  50  and  51  of edge-members  22  are coplanar with first elongate edges  40  and second elongate edges  42  of face-members  20 , respectively. The width of face-members  20  is equal to the full width of stud  10 . In addition, end surfaces  30  and  32  of end-members  24  are flush with first end  31  and second end  33  of face-members  20 , respectively.  
         [0053]    [0053]FIGS. 2 a  and  2   c  show one core-member  26  also sandwiched between and adhesively bonded to face-members  20 , positioned at a point along the length of stud  10 , away from the ends, thereby dividing the void which is formed by the spaced face-members  20  and the spaced edge-members  22 .  
         [0054]    Referring again to FIG. 1, OSB planes of the various members are indicated by two coordinate axes referenced to the individual members. OSB planes  60  and  62  of face-members  20 , OSB plane  61  of edge-members  22 , end-members  24 , and core-members  26  (not shown in FIG. 1) are all substantially parallel. No OSB planes are illustrated in FIGS. 2 a - 2   c , but in FIG. 2 a , OSB planes  60 ,  61 , and  62  would all be parallel to the surface on which the figure is drawn.  
         [0055]    Fabricated wooden stud  10  can be manufactured in a simple and cost-effective manner by a batch process. FIG. 3 illustrates such an approach with a cutaway sketch of a three-layer stud assembly  300  of OSB material.  
         [0056]    Stud assembly  300 , from which studs are cut, is created by arranging edge-strips  101  of OSB (two are labeled but more than two are shown) on OSB face-sheet  100 . Spaces  106  (two are labeled but more than two are shown) between edge-strips  101  are the voids formed by spaced edge-strips  101  and spaced face-sheets  100  and  102 . End-members  24  (two are labeled but more than two are shown) and core-members  26  (two are labeled and shown) are placed at the ends and in spaces  106  between edge-strips  101  as appropriate. Prior to assembly of stud assembly  300 , edge-strips  101 , end-members  24 , and core-members  26  are cut from one or more inner-sheets in a batch process preparatory to the assembly process. Edge-strips  101 , end-members  24 , and core-members  26  are all of equal thickness and in a single layer, in a common plane. OSB face-sheet  102  is placed on top of this second layer, becoming the third layer and completing stud assembly  300 . The OSB planes of all pieces forming stud assembly  300  are parallel.  
         [0057]    During the assembly process, adhesive is applied to all the appropriate surfaces (i.e., at least on adjoining surfaces parallel to the OSB planes) in order to affix together the various members of stud assembly  300 . Stud assembly  300  is then pressed together until the adhesive bonding is secure.  
         [0058]    Acceptable adhesives include adhesives used in the manufacture of OSB, plywood and other engineered lumber. For example, Mira-Lok-#1077 adhesive manufactured by The Huntsman Polyurethanes is an excellent adhesive for this purpose.  
         [0059]    Sawcuts are then made along sawcut lines  80  (two are labeled but more than two are shown) to produce the individual studs. As a result of these sawcuts, portions of edge-strips  101  become edge-members of adjacently-formed studs, and portions of face-sheets  100  and  102  become face-members  20  of adjacently-formed studs.  
         [0060]    The size of typical studs for the building industry varies, with 2×4 (1½″ by 3½″) and 2×6 (1½″ by 5½″) studs being the most common sizes. The fabricated wooden stud disclosed herein, in standard 8-foot lengths, has a weight which is about 18-20% less than standard studs, using two end-members and a single core-member, each of which are 4 inches long. For further cost savings, the thickness of the stud can be reduced to 1⅜″, with the face-members made of {fraction (7/16)}″-thick OSB and the edge-members, end-members, and core-members made of ½″-thick OSB. These typical dimensions are not intended to limit the possible dimensions for the fabricated wooden stud disclosed herein.  
         [0061]    In a highly preferred embodiment of the fabricated wooden stud, the corners of the elongated edges may be broken corners to enhance the safe handling of the stud during use. FIGS. 4 a  and  4   b , both partial end-view schematics of a fabricated wooden stud, illustrate two embodiments of broken corners. FIG. 4 a  shows beveled corner  90 , and FIG. 4 b  shows corner  91  cut with a radius.  
         [0062]    Further, the exposed edges of OSB can be coated with a water-resistant coating to protect the OSB prior to installation of the studs into a building structure.  
         [0063]    Voids  106  which are formed in the interior of the studs, in a common embodiment, are filled with air, forming dead-air spaces which have excellent insulating characteristics. In other embodiments of the inventive stud, voids  106  are filled with other insulating materials which have even better insulating properties than dead air. Such materials include various polymer foams and fiber materials such as fiberglass. FIG. 5 is a partial cutaway perspective drawing of an end portion of an embodiment of fabricated wooden stud  10  which includes insulation  110  in void  106  which is formed by spaced face-members  20  and spaced edge-members  22 .  
         [0064]    A number of variations in the exact form of the fabricated wooden stud are possible, although these are not shown in the figures. For example, the elongate outer surfaces of the edge-members can be inset from the elongate edges of the face-members. In a similar fashion, the end surfaces of the end-members can be inset from the ends of the stud. There may also be situations in which it is desirable to fabricate a wooden stud in which the OSB planes of the edge-members are not substantially parallel to the OSB planes of the face-members.  
         [0065]    Another embodiment of the fabricated wooden stud may include end-members and/or core-members which are not made of OSB but of solid wood or another form of fabricated board such as plywood, particle board or medium density fiberboard (MDF).  
         [0066]    Another embodiment of the fabricated wooden stud may incorporate end-members in which the end surfaces of the end members extend beyond the ends of the face-members.  
         [0067]    [0067]FIG. 6 a  is a schematic of a preferred embodiment of a portion of a production line  200   a  configured to perform the method of this invention. The method is carried out in a batch process, whereby segments  200   a  and  200   b  of a production line  200  are used for more than one step of the inventive method, as described in the following paragraphs.  
         [0068]    The first part of the batch process includes providing a supply of edge-strips  101 , end-members  24 , and core-members  26  shown in FIG. 3. Referring to FIG. 6 a , inner sheets are placed on a feeder infeed  210  which supplies inner sheets one at a time to a feeder  212 . Feeder  212  feeds inner sheets onto an alignment conveyor  214  which then moves the inner sheets through knockout machines  216  which cut wiring pass-throughs at the locations on the inner sheets which will later be cut into core-members. (Two knockout machines  216  are shown, representing the option that more than one pattern of wiring pass-throughs may be cut with this arrangement of equipment in production line  200 .) Inner sheets are then stacked on a feeder  218  and moved by a forklift to an infeed table  220 . A plurality of inner sheets are moved onto a platform  222  and pushed onto a saw platform  224  by a pusher  226 . Pusher  226  incrementally indexes the plurality of inner sheets to various positions on platform  224 , enabling a saw  228  to cut edge-strips  101 , end-members  24 , and core-members  26  from the plurality of inner sheets. Edge-strips  101 , end-members  24 , and core-members  26  are stacked (manually in this embodiment) in infeed magazines  230 , ready to be placed in stud assemblies during the next portion of the batch process.  
         [0069]    Feeder  218 , using vacuum to hold sheet material, collects in sequence first face-sheet  100 , arranged edge-strips  101 , end-members  24 , and core-members  26  (arranged as shown in FIG. 3), and second face-sheet  102  and places them on lay-up lift  232 . Lay-up lift  232  provides an assembly base for initial lay-up of stud assemblies (defined above). Edge-strips  101 , end-members  24 , and core-members  26  are collected from magazines (not shown) movably supported on a magazine conveyor  230 . The magazines are positioned in line with the movement of feeder  218  on a magazine conveyor  230   a . As first face-sheet  100 , arranged edge-strips  101 , end-members  24 , and core-members  26 , and second face-sheets  102  are stacked onto a lay-up lift  232 , an adhesive dispenser  234  moves over and dispenses adhesive onto the upper surface of first face-sheet  100  onto which edge-strips  101 , end-members  24 , and core-members  26  are placed and then dispenses adhesive onto edge-strips  101 , end-members  24 , and core-members  26 , onto which second face-sheet  102  is placed. This three-layer assembly is repeated on lay-up lift  232  until ten three-layer assemblies are stacked together on lay-up lift  232 . Lay-up lift  232 , itself or with one or more three-layer assemblies on it, provides what is referred to herein as the assembly base.  
         [0070]    When ten three-layer assemblies are stacked on lay-up lift  232 , a transfer unit  236  moves the stack onto rollers  238  which are arranged in line with presses  240   a  and  240   b . Transfer units  242   a  and  242   b  move the stack of three-layer assemblies into presses  240   a  or  240   b  respectively, depending on which press is available for use. The press cycle time, during which pressure is applied to the stack, is twice the length of time it takes to assemble the stack of ten three-layer assemblies. After pressing is complete, outfeed rollers  244   a  and  244   b  are used to transfer stacks out of presses  240   a  and  240   b  respectively. Stacks of three-layer assemblies, now referred to as stud assemblies, are removed from outfeed rollers  244   a  and  244   b  by a forklift truck.  
         [0071]    [0071]FIG. 6 b  is a schematic of a preferred embodiment of an additional portion of a production line  200   b  configured to perform the method of this invention. Referring to FIG. 6 b , after a stack of three-layer assemblies is taken from outfeed rollers  244   a  or  244   b  (shown in FIG. 6 a ), the stack is fed into a feeder  246 . Feeder  246  feeds stud assemblies one at a time into a corner transfer unit  248  which aligns the stud assembly with a trim saw  250 . Trim saw  250  trims a minimal amount of material from each end of the stud assembly. The trimmed stud assembly is moved onto a rip infeed conveyor  252  which aligns the trimmed stud assembly against a side alignment fence (not shown) and moves the trimmed stud assembly into a rip saw  254 . Rip saw  254  cuts the trimmed stud assembly into multiple studs of final stud width.  
         [0072]    After the studs are ripped from the trimmed stud assembly, and before the studs are coated with sealant at a coater  262 , it is preferred that the outer corners along the length of the studs be trimmed to have broken corners, i.e., corners having a small radius or slightly beveled character. This can be done for all four corners in a single pass through a device such as a multi-surface sander (not shown).  
         [0073]    An outfeed conveyor  256  and a singulation conveyor  258  transfer the individual studs to an coater infeed  260  which in turn drives the individual studs through a coater  262 . Coater  262  places a sealant on the two elongate edges of the studs.  
         [0074]    Final marking, strapping, and stacking of the studs is done on various pieces of production line conveyance and handling equipment well-known to those skilled in the art of lumber production and labeled as  270  in FIG. 6 b.