Patent Grant
7255765
1. Field of the Invention
The invention relates generally to man-made composite building components and their method of manufacture and assembly. More particularly, the invention relates to the production of composite framing members and integrated components such as studs, walls, roofs, floors, and posts.
2. Description of Related Technology
In conventional building construction, building components such as walls, roofs, floors, and posts may be assembled from wooden framing members and sheathing. Framing members. e.g., lumber, may be produced from natural wood cut in standard sizes from trees such as aspen, spruce, pine, and fir. Sheathing, typically made of plywood or oriented strandboard (OSB), is fastened to the frame of a building component using mechanical fasteners and adhesives such as staples, nails, glue, screws or a urethane foam adhesive.
Traditional lumber produced from natural wood generally has shortcomings in consistency, availability, and cost. Likewise, building components made from traditional materials also have shortcomings in consistency, cost, and ease of assembly.
Conventional lumber from natural wood varies widely in quality. Because framing members, such as nominal 2×4s (actually measuring approximately 1½ inches by approximately 3½ inches), are cut whole from trees or logs as solid pieces, they can possess faults inherent in natural wood, such as knots and splits. Knots typically result in reduced strength in a piece of lumber, requiring a high design safety factor leading to inefficient use of materials. In addition, in a condition known as “waning,” lumber cut from an outer surface of a tree, particularly from younger, smaller trees, can exhibit an undesirable rounded, rather than squared, edge. Also, subsequent to milling, lumber can take on moisture or dry out, which causes a board to become warped and unusable for its intended purpose. These faults contribute to 30-35% of conventional lumber being of a downgraded quality rating.
The lumber that remains suitable for use in construction must often be trimmed, shimmed, nailed to fit, or otherwise adapted for use due to inconsistencies in dimensional accuracy. Furthermore, once installed, lumber is subject to dimensional instability due to environmental factors or the other factors mentioned above. For example, in a condition known as nail pop, installed lumber dries out and shrinks, causing fasteners to move or break loose. Likewise, accidental contact with water or moisture can cause wood to swell and permanently warp.
Natural wood used to produce lumber also is becoming more and more scarce, especially in larger sizes, due to the depletion of old growth forests. This scarcity naturally leads to reduction in quality and/or to the rising cost of conventional lumber and of the homes and businesses built with lumber.
This application also relates to cellulosic, composite articles. One type of composite article is a wood composite such as a man-made board of bonded wood elements and/or lignocellulosic materials, commonly referred to in the art by the following exemplary terms: fiberboards such as hardboard, medium density fiberboard, and softboard; chipboards such as particleboard, waferboard, strandboard, OSB, and plywood. Wood composites also include man-made boards comprising combinations of these materials.
Many different methods of manufacturing OSB are known in the art, such as, for example, those described in Chapter 4.3 of the Wood Reference Handbook, published by the Canadian Wood Council, and The Complete Manual of Woodworking, by Albert Jackson, David Day and Simon Jennings, the disclosures of which are hereby incorporated herein by reference.
The first step in producing a wood composite is to obtain and sort the logs, which may be aspen, balsam fir, beech, birch, cedar, elm, locust, maple, oak, pine, poplar, spruce, or combinations thereof. The logs may be soaked in hot water ponds to soften the wood for debarking. Once debarked, the logs are then machined into strands by mechanical cutting means. The strands thus produced are stored in wet bins prior to drying. Once dried to a consistent moisture content, the strands are generally screened to reduce the amount of fine particles present. The strands, sometimes referred to as the filler-material, are then mixed in a blending operation, adding a resin binder, wax, and any desired performance-enhancing additives to form the composite raw material, sometimes called the furnish. The resin-coated or resin-sprayed strands then are deposited onto a forming line, which arranges the strands to form a loosely felted mat. The mat thus formed also can be referred to as an array of strands. The mat, including one or more layers of strands arranged with a selected orientation (including, for example, a random orientation), is then conveyed into a press. The press consolidates the mat under heat and pressure, polymerizing the resin and binding the strands together to form a consolidated array of strands with other additives, including the binder. The boards are then conveyed out of press into sawing operations which trim the boards to size.
It is an object of the invention to overcome one or more of the problems described above.
Accordingly, one aspect of the invention is a composite building component that includes a non-planar molded composite web having two outer zones and two angled zones wherein the caliper of the angled, zones differs from the caliper of at least one of the outer zones, and a flange disposed on an outer surface of an outer zone.
Another aspect of the invention is a composite building component including a web having at least one channel defined by a first outer zone, a second outer zone, and at least two angled zones, each of the zones having a caliper, and each of the zones having inner and outer surfaces; a first flange joined to the web at an outer surface of the first outer zone; a second flange joined to the web at an outer surface of the second outer zone; wherein the width of the building component, measured in a direction parallel to a channel, is not greater than the thickness of the building component, said thickness measured as a distance between parallel outer surfaces of the flanges.
Still another aspect of the invention is a composite building component including a non-planar, molded array of wood strands defining a web panel having a caliper and having first and second undulating principal surfaces, the surfaces providing an alternating pattern of first and second sets of ridges extending parallel to each other and oppositely disposed with respect to a center line of the web panel, adjacent ones of the ridges in the first set being connected to intermediate ones of the ridges in the second set by sloped walls, and the caliper of the web panel between the first and second principal surfaces being different in the vicinity of at least one of the first and second sets of ridges as compared to the sloped walls.
Yet another aspect of the invention is a method of producing a composite building component including the steps of: (a) forming a mat including a wood-based material; (b) providing the mat in a die set, the die set having a non-planar configuration with at least two outer zones and at least two angled zones; (c) closing the die to form a die gap, wherein the die gap in at least one of the outer zones differs from the die gap at the angled zones; (d) consolidating the mat under pressure and heat to form a molded composite web; and (e) joining the web with at least one flange, to form the composite building component.
A further aspect of the invention is a method of producing a building component including the steps of: (a) forming a mat including an array of wood strands; (b) providing the mat in a die set, the die set having a non-planar configuration with first and second die surfaces; (c) closing the die to form a die gap, wherein the die gap provides an alternating pattern of first and second sets of ridges extending parallel to each other and oppositely disposed with respect to a center line of the die set, wherein adjacent ones of said ridges in the first set are connected to intermediate ones of the ridges in the second set by sloped walls formed by the die gap, and wherein the die gap between the first and second die surfaces is different in the vicinity of at least one of the ridges as compared to the sloped walls; (d) consolidating the mat under pressure and heat to form a molded composite web panel; and (e) joining the web with at least one flange, to form the composite building component.
Other objects and advantages of the invention may become apparent to those skilled in the art from a review of the following detailed description, taken in conjunction with the drawings and the appended claims. While the invention is susceptible of embodiments in various forms, described hereinafter are specific embodiments of the invention with the understanding that the disclosure is illustrative, and is not intended to limit the invention to the specific embodiments described herein.
According to the present invention, there is provided a method and apparatus for producing multi-ply or multi-layered composite building components from wood-based materials. The wood-based materials can be, for example, flakes, wafers, particles, fibers, and/or strands, including mixtures thereof. Generally, the building components can be provided by coating or spraying one or more wood-based materials such as flakes or fibers with a resin binder and optionally with a wax and other performance-enhancing fillers to form the composite raw material or furnish. The composite raw material or furnish is formed into a mat of generally uniform basis weight. The mat is loaded into a die set having a desired geometry and consolidated in a heated press to form a composite panel. A die set used to produce a molded or contoured composite panel is described below in detail. One or more of these panels is bonded with a second non-planar or planar flange, and optionally with one or more end blocks or other framing members, to produce a multi-ply wood composite product of the invention. In a preferred embodiment of the invention, the bonded assembly is subsequently cut into multiple multi-ply wood composite building components.
The multi-ply composite building components of the invention preferably include OSB components made from a raw material obtained by breaking down logs or other source of wood into strands, as described above. Various methods of producing these strands are known in the art. The strands preferably are produced through mechanical slicing and flaking. Exemplary sources of wood materials are: aspen, balsam fir, beech, birch, cedar, elm, locust, maple, oak, pine, poplar, spruce, or combinations thereof. Aspen or pine is preferred, but the wood used will depend upon availability, cost, and special use requirements. The type of wood-based material used will define the type of board and properties produced. For example, the invention can include components defined as flakeboard, waferboard, strandboard, OSB, and/or fiberboard. Oriented strandboard is preferred.
Ranges of exemplary and preferred dimensions of strands for use in a preferred composite panel are described below in Table 1.
Once produced as described above, the strands preferably are processed to reduce the level of fine particles and dust. This step preferably is achieved by sending the strands through a rotary screen classifier or by other suitable means. In general, the level of fines can be up to about 60 weight percent (wt. %) (based on total weight of the wood-based material) at an about ⅛ inch (about 3.2 mm) screen size or finer, and more preferably in a range of about 20 wt. % to about 30 wt. %. (Unless otherwise noted, the percentages expressed herein are based upon weight.) The mixture of wood-based material is sometimes referred to simply as wood strands.
The moisture content of the processed strands preferably is in a range of about 2 wt. % to about 9 wt. %, and more preferably in a range of about 4 wt. % to about 6 wt. %, based on the weight of the wood-based material.
The strands (and any accompanying particles and dust) then are mixed in a blending operation, preferably adding a resin binder, wax, and any other desired performance-enhancing additives, to form the composite raw material used to produce the boards of the invention. Preferred resin binders include phenolic resins, resorcinol resins, and MDI resins, although any suitable resin can be utilized. Preferably, the resin content is in a range of about 1 wt. % to about 10 wt. % of the weight of the wood-based material, and more preferably in a range of about 3.5 wt. % to about 5.5 wt. %. When using MDI resins, less resin is generally required than when using phenolic or resorcinol resins. In addition to allowing for reduced resin usage, use of an MDI resin allows for decreased press temperatures (resulting in reduced energy input) and permits the use of raw materials with higher moisture contents.
Ingredients can be added to the raw material to impart various beneficial properties to the composite building components of the invention. For example, fire retardants, insecticides, fungicides, water repellants, ultraviolet radiation (UV) blockers, pigments, and combinations thereof can all be used in alternative embodiments of the invention. An exemplary fire retardant is sold under the trademark D-BLAZE by Chemical Specialties, Inc., of Charlotte, N.C. Wax preferably is added to improve moisture resistance, preferably in a range of about ½ wt. % to about 2 wt. % of the weight of the wood strands, for example at about 1 wt. %. An exemplary wax is sold under the trademark EW 58 LV by Borden of Diboll, Tex.
The raw material then is continuously deposited on a forming line to form a mat of generally uniform basis weight. In another embodiment of the invention, the mat can be formed individually in a batch process. The basis weight of a mat is calculated as the volume of the molded panel multiplied by the target density of the molded panel divided by the surface area of the formed mat, and has units lb/ft2 or kg/m2.
The individual strands in the mat can be imparted a selected orientation (generally in the case of OSB), or the mat can be assembled with strands in random orientation. OSB generally refers to a board produced from a mat wherein the strands are imparted with a selected orientation, but can also refer to a board produced from a mat wherein the strands are imparted with or have a random orientation. Individual strand layers within a single mat can, but need not, have different orientations. The strand orientation affects the mechanical performance characteristics of the consolidated composite board, so the preferred strand orientation will differ from application to application.
A continuously-formed mat is then cut to size, having a length and width roughly equal to, or slightly larger than, the length and width of a desired panel produced by a suitable die set. Thus, a consolidated panel is limited in length and width only by the size of the equipment used to produce the panel.
The mat is then loaded into a die set having the desired geometry. The temperature of the press platens and die set during mat consolidation using a phenolic resin preferably is in a range of about 420° F. to about 480° F. (about 215° C. to about 249° C.), and more preferably about 450° F. (about 232° C.). As will be apparent to those of skill in the art, desirable pressing temperatures and pressures can be modified according to various factors, including the following: the die geometry; the type of wood being pressed; the moisture content of the raw material; the press time; and the type of resin that is utilized. The moisture content of the raw material is one important factor which controls the core temperature of the mat that can be achieved under given press conditions and therefore may control the press cycle. Press time can generally be decreased by increasing press temperature, with certain limitations as is known in the art.
Steam injection pressing is a consolidation step that can be used, for example, under certain circumstances in production of consolidated cellulosic composites. In steam injection pressing, steam is injected through perforated one or more heating press platens and/or dies, and then into, through, and then out of a mat. The steam condenses on surfaces of the raw material and heats the mat. The heat transferred by the steam to the mat as well as the heat transferred from the press platens and/or die set to the mat cause the resin to cure. When compared with conventional pressing operations, steam injection pressing can, under certain circumstances, provide a variety of advantages, such as, for example, shorter press time, a more rapid and satisfactory cure of thicker panels, and products having more uniform densities.
According to an embodiment of the inventive method, a first mat is consolidated under heat and pressure in an apparatus configured to produce a molded composite web having one or more contoured features (e.g., features referred to as ridges, ribs, channels, projections, flat zones, upper zones, outer zones, raised zones, or sloped walls), including features upwardly and/or downwardly disposed from a center line or major planar surface of the panel, as described below in greater detail. The compressed panel can be referred to as a molded array of raw material, such as a molded array of wood strands. The projections preferably are evenly spaced apart. Upon pressing, the panel retains integrity and does not fracture. The panel is then edge-trimmed to size.
Preferred embodiments of the inventive articles generally include multiple OSB components which may or may not have the same configuration and composition. Thus, one or more additional mats are each consolidated under heat and pressure in an apparatus configured to produce a panel having a desired configuration. These additional composite panels can be flat or can have molded or contoured features, and are likewise edge-trimmed to size. These additional composite panels are also described in greater detail below.
One or more of the additional panels are aligned and bonded with the first panel, and optionally with end blocks or other framing members, to form a wood composite building component of the invention. Any suitable adhesive can be used to bond the panels and optional end blocks with each other. A preferred bonding adhesive, applied at the interfaces an/or joints between panels, will provide a shear strength that is at least about equal to the shear strength of the composite panels themselves. A preferred bonding adhesive can be selected from the group consisting of hot melt polyurethane, moisture curing hot melt polyurethane, moisture curing polyurethane adhesives, and combinations thereof. The adhesive preferably is applied at a rate in a range of about ¼ oz./ft2 of contacting surface area (about 7.4 ml/cm2) to about ¾oz./ft2 (about 22 ml/cm2), for example about ½ oz./ft2 (about 14 ml/cm2). In an alternative embodiment of the invention, waterproof resorcinol adhesives or an isocyanate or MDI-based adhesive can be used. In another alternative embodiment, the glue can either be replaced with or assisted by mechanical fasteners, such as staples.
In a preferred embodiment of the invention, the bonded assembly is subsequently cut into multiple wood composite building components, as described below.
The advantageous properties of the inventive product allow it to be an excellent component in construction applications such as lumber components, floors, walls, roofs, and framing members. This process according to the invention produces a composite component that integrates an engineered combination of various desired properties useful in building components such as compressive and bending strength, bending stiffness, impact deflection, and increased resistance to water, insects, bacteria, and fire.
Various preferred embodiments of the invention will now be described in more detail.
Composite Lumber
The inventive process can be used to produce a composite lumber product of the invention suitable as a replacement for conventional lumber, or an embodiment engineered with dimensions and strength characteristics for specific applications not suitable for conventional lumber. Referring initially to
It is to be understood that the terms web, flange, and end block are used to refer to these individual components either as panels and beams in the bonded assembly 20 or as elements of the individual lumber components produced by dividing the bonded assembly 20 along lines 25, as described above and shown in
A method of producing one embodiment of a web panel 21 will now be described with respect to a composite lumber embodiment of the invention. It is to be understood, however, that the characteristics of the web panel 21 and its method of manufacture are equally applicable to a web panel 21 used alone in certain applications and in applications with additional components, including the other embodiments of the invention described later, such as, for example, a decking component.
In a preferred method of producing a composite lumber product of the invention, the mat which will become the web panel 21 is formed of up to three layers of resin-coated, loosely felted, oriented strands in the continuous process described above. The mat can be referred to as comprising an array of wood strands. For example, a first, or bottom, layer is formed in the direction parallel to the longitudinal axis of a finished lumber component. This first layer preferably constitutes about ⅓ to about 100% of the total mat weight. A second, or middle, layer can be formed perpendicular to the direction of the first layer and can comprise up to about ⅓ of the total mat weight. A third, or top, layer can be formed parallel to the first layer and can constitute up to about ½ of the total mat weight. In other words, from one to three layers preferably are included in the mat, wherein each layer generally has strands oriented in a direction perpendicular to the strands in an adjacent layer. In one preferred embodiment, each layer comprises about ⅓ of the total weight of the mat.
In another preferred embodiment, about 80% to about 100% of the strands are oriented in the direction parallel to the longitudinal axis of a lumber component, for example about 90% of the strands. In one version of that embodiment having three layers, the strands oriented in the direction parallel to the longitudinal axis of a lumber component are distributed approximately equally, e.g., by weight, between the top and bottom layers of the mat. In another version of such an embodiment having multiple layers, the strands oriented in the direction parallel to the longitudinal axis of a lumber component are distributed approximately equally by weight throughout all layers of the mat.
In one preferred embodiment, the dimension of the web panel 21 in the direction perpendicular to the channels 24 roughly corresponds to the desired length of a completed composite lumber product of the invention. In another preferred embodiment, the dimension of the web panel 21 in the direction perpendicular to the channels is less than the desired length of the completed composite lumber component of the invention to provide space for end block beams 22, as in the embodiment of
The width of the web panel 21 (i.e., in the direction perpendicular to the lines 25) and, thus, the mat used to produce web panel 21, preferably is as great as possible in order to maximize the efficiencies of production of multiple lumber components from one bonded assembly 20. For example, in a 4 foot (about 1.2 m) by 8 foot (about 2.4 m) heated press used to produce composite lumber about 8 feet (about 2.4 m) long, the web panel 21 preferably is about 4 feet (about 1.2 m) wide. Most preferably, an 8 foot (about 2.4 m) by 24 foot (about 7.3 m) heated press is used to produce composite lumber about 8 feet (about 2.4 m) long, with a web panel 21 preferably about 24 feet (about 7.3 m) wide (i.e., in the direction perpendicular to the lines 25).
A preferred process for producing an inventive composite lumber article will now be described. Referring to
As the die set 26 is closed on the mat, the wood strands of the mat preferably shift or slide within the matrix of the mat (or, in one embodiment of the invention, within the array of wood strands), grossly conforming to the die configuration. It has been found that, due to compressing and shearing forces on the mat created by the interaction between the upper die 27 and the lower die 28, the surface area of the mat can increase as much as 75 percent, preferably about 15 to about 25 percent, most preferably about 20 percent. Because of the unlocked state of the strands in the loosely felted mat, they generally tend to shift at certain regions of the mat during the compression operation. Factors influencing the amount that the surface area of a mat may increase during pressing using the process of the invention include: the geometry or contours of the web panel 21 (or, in other words, the contours or profile of the web panel 21); the variation in caliper among various locations of the web panel 21 (or, in other words, the variation in die gap among various locations of die set 26); the mat basis weight and orientation of the strands prior to press closure; and the strand geometry (including physical length, width and thickness). These factors affect the ability of the strands to shift or slide within the matrix of the mat before bypassing, fracturing, or destroying the continuity of the composite mat during press closure. The process used and the unique die configuration used according to the invention help to optimally combine these factors so that the surface area of the mat can increase without fracturing the mat, especially at the outer zones 33. At the same time, the process preferably provides a product with at least substantially uniform density, resulting in increased strength of the molded board and of objects constructed therefrom. In contrast, compressed products of prior methods have been characterized by undesirable density variations, resulting in reduced strength of a molded board and of objects constructed therefrom.
The temperature of the press platens and/or die set during mat consolidation using a phenolic resin preferably is in a range of about 420° F. to about 480° F. (about 215° C. to about 249° C.), and more preferably about 450° F. (about 232° C.). The pressing time depends on the caliper of the finished product and the other factors listed above, but is generally in a range of about 1 minute to about 5 minutes in preferred embodiments of the invention.
The caliper of a consolidated web at any particular point is defined by a distance or gap between the first die 27 and second die 28 during pressing and consolidation of a mat. For example, the die gap at one location of the die set 26 is defined by the distance between point 29 and point 30 in
Preferably, the caliper of the web 21 at the upwardly disposed outer zones 33a, 33b, and 33c (as shown in
In one preferred embodiment, the caliper of the web tapers (for example, by linear decrease in caliper) from a thicker downwardly disposed outer zone (e.g., zone 33d in
In a composite lumber embodiment of the invention, the caliper of the web 21 preferably is in a range of about ⅛ inch to about 1 inch (about 3.18 mm to about 25.4 mm), more preferably in a range of about ¼ inch to about ½ inch (about 6.35 mm to about 12.7 mm). The caliper at the outer zones 33a, 33b, 33c preferably is in a range of about 0.215 inch to about 0.465 inch (about 5.5 mm to about 11.8 mm), while the caliper at the outer zones 33d, 33e, 33f preferably is in a range of about 0.250 inch to about 0.50 inch (about 6.35 mm to about 12.7 mm).
The web panel 21 according to the invention preferably has a specific gravity in a range of about 0.6 to about 0.9 at any location in the panel, more preferably about 0.65 to about 0.75, most preferably about 0.75 when using southern yellow pine as the cellulosic component in the raw material. The overall specific gravity of the panel preferably is in a range of about 0.6 to about 0.9, more preferably about 0.65 to about 0.75, most preferably about 0.75 when using southern yellow pine as the cellulosic component in the raw material, making it a high density wood composite. The varying die gap preferably allows for the production of a web panel 21 having an at least substantially uniform density throughout its profile. Preferably, the density of the web 21 at an outer zone 33 is at least about 75% of the density of the web 21 at an angled zone 34, more preferably at least about 90%, for example about 95%. Likewise, the density of the web 21 at an upwardly disposed outer zone (e.g., 33a) preferably is at least about 75% of the density of the web 21 at a downwardly disposed outer zone (e.g., 33d), more preferably at least about 80%, most preferably at least about 90%, for example about 95%.
Whereas the outer zones 33 of the web panel 21 shown in
Thus, it is understood that the use of the term flat herein refers to a generally planar portion. In another alternative embodiment, an outer zone 33 can be the peak of a curved portion of the web 21. In yet another embodiment, an outer zone 33 can have a caliper that increases or decreases from the center of the zone 33 to the end of the zone 33 which is contiguous with, and integrally formed with, an angled zone 34.
Likewise, the angled zones 34 shown in
The angled zones 34 can form various angles with the outer zones 33. These angles can be referred to as draft angles. For example, referring to
Draft angles α and β of a web 21 preferably are in a range of about 30 degrees to about 60 degrees, more preferably in a range of about 35 degrees to about 55 degrees, and most preferably in a range of about 40 degrees to about 50 degrees, for example about 45 degrees in a preferred composite lumber article. In another embodiment of the invention, the draft angle α or β of a web 21 is greater than 45 degrees. The increased draft angles, especially draft angles greater than about 45 degrees, provide substantial advantages in the web panel 21 of the invention, such as the ability to span greater distances with reduced material cost and increased strength.
Referring to
A radius 35 of the web 21 generally varies with the overall caliper of the web 21. For example, the radius 35a of the web 21 at the intersection between an angled zone 34 and an upwardly disposed outer zone (e.g., 33a) generally varies with the caliper of the upwardly disposed outer zone (e.g., 33a). Preferably, the radius 35a dimension is equal to about one to about three times the caliper at adjacent zones of the web 21. In a specific embodiment, this dimension is approximately 1.5 times the caliper of the web 21 at the adjacent outer zone.
Exemplary radii 35a are tabulated in Table II below for various calipers of an upwardly disposed outer zone 33.
The profile thickness or profile depth of the web 21 (measured by the greatest depth of the web, for example, referring to
The depth of draw of a web 21 is measured as the vertical distance traveled by an angled zone 34 between the center lines of adjacent outer zones (e.g., the zones 33a and 33d). Whereas the depth of draw can be uniform throughout a web 21, this need not be the case. Thus, for example, the top surfaces of the outer zones 33a, 33b, and 33c are preferably, but optionally, in a single plane. The depth of draw of the web 21 preferably is about 6 inches (about 15.24 cm) or less, and more preferably in a range of about ¼ inch to about 31/2 inches (about 6.35 mm and about 88.9 mm). In one preferred embodiment of the invention, the depth of draw of the web 21 is greater than the caliper of any zone.
A web segment 36, depicted in
The strength properties of composite lumber articles depends in part on the frequency of web segment repeat. In general, as the frequency of web segment repeat increases, the deflection strength of the lumber article increases. The following design factors interrelate to provide deflection resistance of a web, and therefore to an article including the web: (a) length of the lumber desired; (b) width of end block used (if any); (c) draft angle of angled zone 34 (which itself depends on the raw material used and the depth of draw); (d) web caliper at the various zones and intersections of the zones; (e) web 21 density; (f) area of interface between web 21 and flange 23; and (g) type and amount of adhesive between web 21, one or more flanges 23, and one or more end blocks 22. These factors can be selected so as to achieve a desired deflection resistance.
Preferably the angle γ and length of the flattened shoulder 51 are selected to provide a caliper of the web 21 in the vicinity of the intersection between an angled zone 34 and an outer zone (e.g., downwardly disposed outer zone 33d) that transitions between the caliper of an outer zone and the caliper of an angled zone 34. Most preferably, the angle γ and length of the portion 51 are selected to provide a web caliper 21 in the vicinity of the intersection between an angled zone 34 and an outer zone (e.g., downwardly disposed outer zone 33d) that corresponds to the distribution of raw material in the die set 26 in the vicinity of the intersection between the angled zone 34 and the outer zone (e.g., 33d) after the die set 26 is closed, to provide a substantially uniform density of the web 21. Thus, preferably the flattened shoulder 51 feature is used at the intersection of an angled zone 34 and a downwardly disposed outer zone, e.g., 33d.
The angle γ preferably ranges between about 20 and about 50 degrees, and more preferably is between about 25 and about 35 degrees. In an exemplary embodiment, the angle γ is substantially equal to 31 degrees.
In another embodiment of the invention, the consolidated web panel 21 has first and second undulating principal surfaces, formed by the first (upper) die 27 and the second (lower) die 28, respectively. The first and second principal surfaces provide an alternating pattern of first and second sets of ridges extending parallel to each other and oppositely disposed with respect to a center line of the web panel 21 (e.g., elements 33 in
Characteristics of this web panel 21 embodiment of the invention can be the same as those of the previously-described web panel 21. For example, in a preferred embodiment, the caliper of the web 21 gradually increases or decreases from a sloped wall to a ridge via a radiused connection.
Referring to
The flange 23 also contributes to the deflection resistance of a composite lumber product. Thus, the flange preferably is made from a material that, in combination with the web, provides the desired deflection resistance for a particular application. In one preferred embodiment of the invention, the flanges are OSB, made from the same raw material as the web 21 according to the methods described above. In such an embodiment, the strands of the flange 23 preferably are oriented in the direction perpendicular to the channels 24 of the web 21, and the caliper of the flange 23 preferably is in a range of about ⅛ inch to about 1 inch (about 3.2 mm to about 25.4 mm). The opposing flanges preferably are of about equal caliper, however, the inventive articles can use two completely different flanges (both with respect to caliper and material) in certain applications.
The flange 23 of the lumber article preferably is generally planar with a uniform cross-sectional dimension (or caliper). However, it is to be understood that other flange configurations are useful with the invention. For example, in one alternative embodiment, a flange 23 itself is a web 21 having one or more of the characteristics described above. When a flange 23 is itself a web 21, the term nominal flange 23 is used to refer to its particular web-like properties. Alternatively, such a multi-ply assembly may be referred to simply as including one or more web 21 panels. Preferably, such a nominal flange 23 has a relatively small depth of draw [e.g., in a range of about 1/16 to about ½ inch (about 1.6 mm to about 12.7 mm)], a frequency of web segment 36 repeat, and outer zone 33 length sufficient such that one or more outer zones 33 of the nominal flange 23 comes into contact with one or more outer zones 33 of the web 21.
Preferably, the flange 23 panels have one dimension, referred to hereafter as length, which is approximately equal to the length of the desired composite lumber article. Referring to
In general, an optional end block 22 of the composite lumber article of the invention can be made from any material or combinations of materials, including laminated veneer lumber (LVL), solid conventional lumber, plywood, laminated strand lumber (LSL), parallel strand lumber (PSL), particle board, OSB, strand board (wafer board), fiberboard, corrugated board, kraft paper, plastics, fiberglass, and metals. Preferably, the end block 22 is constructed of material of sufficient strength to hold a mechanical fastener, most preferably of a nailable material. In one preferred embodiment of the invention, an end block 22 is constructed from particleboard. In another preferred embodiment of the invention, an end block 22 is constructed from the offstock of flange 23 production. Preferably, opposing end blocks 22 are made from the same materials, however, the invention can include end blocks 22 made from two different materials or two end blocks 22, each made from different materials.
An optional end block 22 beam preferably has a length roughly equivalent to the width of the flange panels 23 (which is roughly equivalent to the width of the web panel 21).
Referring to
Referring to
To assemble a preferred intermediate bonded assembly 20, bonding adhesive is applied to the interfaces between components, and the components are aligned. For example, adhesive can be applied to the outer surfaces 133a, 133b, and 133d (
Subsequent to application of the bonding adhesive and alignment of the components, the entire bonded assembly 20 is conveyed into a press, preferably a continuous nip press or a platen press, for a predetermined period of time, and subjected to elevated pressure and/or temperature sufficient to cure and/or dry the adhesive.
To produce a composite lumber article, the bonded assembly 20 is then conveyed to a multiple-arbor saw. The saw cuts the bonded assembly 20 in the direction perpendicular to the channels 24, along the lines 25. The width between the arbors is about equal to the width of the desired composite lumber articles, for example about 1½ inches (about 3.81 cm), the width of a nominal 2×4. Using this method, multiple multi-ply wood composite lumber embodiments of the invention can be produced from a single bonded assembly 20.
A support post 37, one example of which is depicted in
Added performance such as coloring and resistance to fire, insects, bacteria, and water can also be achieved by the addition of suitable performance-enhancing additives and/or by the application of suitable specialty coatings to the surfaces of the composite lumber articles of the invention.
Composite lumber embodiments of the invention can be designed to have the same outer dimensions as conventional lumber and modulus of elasticity and moment of inertia sufficient to meet construction requirements for typical applications. However, the invention is also applicable to the production of lumber components having alternative cross sectional dimensions, and in lengths limited only by the size of the equipment used to produce the individual components of the assembly 20.
Furthermore, the invention can also provide composite lumber articles having performance characteristics that differ from their conventional lumber counterparts. For example, conventional 2×6 (nominal) lumber is frequently used in building construction to provide a 5½ inch (about 14 cm) deep space for R-19 insulation between sheathings, but is typically much stronger than necessary to meet building code requirements, thereby increasing the cost of a construction project. A multi-ply wood composite lumber component of the invention nominally measuring 2×6 may have the same cross-sectional dimensions as a conventional 2×6, but can be engineered to specific (e.g., increased or decreased compared to conventional wood lumber) strength requirements. Thus, one advantage of the invention is the ability to provide a building component that meets or exceeds the building code requirements but, among other advantages, uses less starting material, weighs less, and is less expensive to produce than a conventional article, such as a conventional 2×6.
Example of Nominal 2×4 of the Invention
An example of a preferred composite product of the invention (shown in an isometric view in
The construction of a preferred 2×4 article 38 of the invention will now be described. A preferred web 21 can be made from strands having a length in a range of about 4½ inches to about 5½ inches (about 11.4 cm to about 14 cm), width in a range of about ¾ inch to about 1 inch (about 19 mm to about 25.4 mm), and thickness in a range of about 0.02 inch to about 0.025 inch (about 0.51 mm to about 0.64 mm). The strands utilized in a preferred web 21 have a pre-pressing moisture content in a range of about 2% to about 9%, preferably in a range of about 4% to about 6%, for example about 5%, based upon weight of the strands.
The mat is produced as described above by combining strands, resin binder, a wax, and other optional additives. A preferred resin binder for the web 21 is a resorcinol resin, preferably added at about 4½ wt. % based upon the weight of the wood strands. Wax preferably is added to the raw material in a range of about 1½ wt. % to about 2 wt. %, for example about 1½ wt. %, based upon the weight of the wood strands.
In a preferred 2×4 embodiment, the mat which will become the web 21 is formed of three layers of raw material including strands, according to the continuous process described above. The strands of the first (bottom) and third (top) layers are oriented in the machine direction (i.e., in the direction perpendicular to channels 24) and comprise about 90% of the total mat weight, divided about equally between the two layers. The strands of the second, or middle, layer are oriented perpendicular to the machine direction (i.e., in the direction parallel to channels 24) and comprise the remainder, about 10% of the total mat weight.
The composite 2×4 articles of the invention preferably are made having lengths of about 81.75 inches (about 2.08 m), about 87.75 inches (about 2.23 m), or about 96 inches (about 2.44 m), to correspond to lengths typically used in construction industries. One type of preferred web 21 for use in the above articles has lengths of about 81.75 inches (about 2.08 m), about 87.75 inches, (about 2.23 m) or about 96 inches (about 2.44 m), respectively. In an alternative web embodiment, the preferred lengths are about 75.75 inches (about 1.92 m), about 81.75 inches (about 2.08 m), or about 90 inches (about 2.29 m), respectively to provide an approximately 3 inch (about 7.6 cm) space at each end for end blocks.
The width of the web panel (and, thus, the mat used to produce the web) preferably is as great as possible in order to maximize the efficiencies of production of multiple lumber components from one bonded assembly 20. For example, in a 4 foot by 8 foot (about 1.22 m by 2.44 m) heated press used to produce composite 2×4 lumber about 8 feet (about 2.44 m) long, the web panel preferably is about 4 feet (about 1.22 m) wide. Most preferably, an 8 foot (about 2.44 m) by 24 foot (about 7.32 m) heated press is used to produce composite 2×4 lumber about 8 feet (about 2.44 m) long, with a web panel preferably about 24 feet (about 7.32 m) wide.
The temperature of the press platens during mat consolidation using a phenolic resin preferably is about 450° F. (about 232° C.). The pressing time depends on the caliper of the finished product and the other factors listed above, but is generally in a preferred range of about 2.5 minutes to about 3 minutes for a preferred web of the invention for use in 2×4 composite lumber applications.
The web panel 21 according to the invention preferably has a specific gravity in a range of about 0.6 to about 0.9 at any location in the panel, most preferably about 0.75. The overall specific gravity of the panel preferably is in a range of about 0.6 to about 0.9, for example 0.75, making it a high density wood composite. The varying die gap preferably allows for the production of a web panel 21 having an at least substantially uniform density throughout its profile. Preferably, the density of the web 21 at an outer zone 33 is at least about 75% of the density of the web 21 at an angled zone 34, more preferably at least about 90%, for example about 95%. Likewise, the density of the web 21 at an upwardly disposed outer zone (e.g., 33a) preferably is at least about 75% of the density of the web 21 at a downwardly disposed outer zone (e.g., 33d), more preferably at least about 80%, most preferably at least about 90%, for example 95%.
The caliper of the web 21 of the article 38 preferably is in a range of about ¼ inch to about ½ inch (about 6.35 mm to about 12.7 mm). The caliper of the angled zones 34 preferably is greater than that of the upwardly disposed outer zones 33a, 33b, and 33c. The caliper of the downwardly disposed outer zones 33d, 33e, and 33f preferably is at least about equal to that of the angled zones 34. For example, in the article 38 of
The outer zones 33 of the web 21 preferably have a length of about 6 inches (about 15.24 cm) or less, or about 2 inches (about 5.08 cm) or less, for example about 1.1688 inches (about 2.97 cm). The outer zone 33 of the web 21 can be longer than 2 inches in special applications. The draft angle of the web 21 of the article 38 preferably is about 45 degrees.
Table III below summarizes preferred dimensions for a tapered composite lumber web 21 useful as a component of a nominal 2×4, wherein the web 21 has a profile thickness equal to about two inches (5.08 cm), a web segment 36 length equal to about 3.175 inches (8.06 cm), a draft angle β equal to about 45 degrees, an angle γ in the range of about 25 degrees to about 35 degrees, and radii 35b and 35c each independently established in a range between approximately 0.15 inches (3.81 mm) and approximately 0.35 inches (8.89 mm), for example 0.25 inches (6.35 mm). The caliper of angled zone 34 at three different locations is indicated in
The flanges 23a and 23b of the article 38 preferably are OSB, made from the same raw material as the web 21 and oriented with the strands perpendicular to the channels 24 of the web 21 (i.e., parallel with the longitudinal axis of the article 38). The flange 23 preferably has a length of about 8 feet (about 2.43 m). The caliper (thickness) of the flange 23 preferably is in a range of about ⅛ inch to about 1 inch (about 3.18 mm to about 25.4 mm), and more preferably in a range of about ½ inch to about 1 inch (about 1.27 cm to about 2.54 cm), for example about 0.75 inches (about 1.9 cm) in a preferred flange 23 embodiment useful in a nominal 2×4 embodiment of the invention.
In one preferred embodiment of the invention, the end block 22 width (measured in
The web panel 21, flange panels 23, and end blocks 22 then are assembled and bonded according to the method described above to form a bonded assembly 20, as shown in
The bonded assembly 20 then is conveyed to a multiple-arbor saw. The saw cuts the bonded assembly in the direction perpendicular to the channels 24 of the web 21 along lines 25 of
A composite 2×4 of the example is designed to meet construction specifications for applications in which conventional 2×4s are used as studs. In a preferred 2×4 embodiment, the flange 23 has a minimum modulus of elasticity of about 900,000 lb/in2. For example, in a test method described by Fleetwood Enterprises, Inc., of Riverside, Calif. and HUD standards, a nominal 2×4 is supported at the top and bottom (in contact with the side measuring 1½ inches (3.8 cm)) and an evenly distributed load is applied over the length of the component. To pass a “live load” test, a 2×4 does not break immediately after application of 2½ times the “live load.”. To pass a deflection test, the 2×4 must not be displaced at the midpoint more than a maximum allowable deflection value. The live load is determined by the wind load, which is about 15 lb/ft2 (73 kg/m2) multiplied by the length of the lumber component and multiplied by the distance that the studs are spaced apart in a wall. The allowable deflection is determined by the 2×4 length divided by 180. For example, for a 2×4 having length of about 81.75 inches (about 2.08 m) and spaced apart about 16 inches (about 40.64 cm), the live load is about 136 pounds (about 61.7 kg) and the allowable deflection is about 0.45 inch (about 11.43 mm); for a 2×4 having length of about 87.75 inches (about 2.23 m) and spaced apart about 16 inches (about 40.64 cm), the live load is about 146 pounds (about 66.3 kg) and the allowable deflection is about 0.49 inch (about 12.45 mm); and for a 2×4 having length of about 96 inches (about 2.44 m) and spaced apart about 16 inches (about 40.64 cm), the live load is about 160 pounds (about 72.6 kg) and the allowable deflection is about 0.53 inch (about 13.46 mm).
Decking
The inventive process can be used to produce an integrated composite decking component product of the invention suitable as a replacement for conventional decking, or engineered with dimensions and strength characteristics for specific applications.
The decking panel 42 preferably includes at least one cavity 44, preferably one or more rows and/or one or more columns of cavities 44 (shown from the side in
A decking panel 42 of the invention preferably is strand board, wherein the raw material is formed according to the process described above. A mat which becomes the consolidated decking panel 42 preferably is formed of up to three layers of raw material in the continuous process described above, and then cut to size. The strands in a decking panel 42 can be randomly oriented or can be imparted with a specific orientation. Preferable, the strands in a decking panel 42 are randomly oriented. In addition, the decking material optionally can include performance-enhancing materials such as those described above.
In one preferred embodiment, the caliper of the decking panel 42 at the cavity floor 47 and at cavity side walls 45 is greater (thicker) than the caliper of the panel 42 at the lattice 46. In a preferred decking panel 42, the caliper of the cavity floor 47 is at least about equal to the caliper of the cavity side walls 45, and the ratio of the caliper of the lattice 46 to the caliper of the cavity side walls 45 is at least about 0.75, and more preferably in a range of about 0.8 to about 0.9, for example about 0.85.
In another preferred embodiment, the caliper of the decking panel 42 at the cavity floor 47 is less (thinner) than the caliper of the panel at the cavity side walls 45 and lattice 46. In such a decking panel, the caliper of the lattice 46 is at least about equal to the caliper of the cavity side walls 45, and the ratio of the caliper of the cavity floor 47 to the caliper of the cavity side walls 45 is at least about 0.75, and more preferably in a range of about 0.8 to about 0.9, for example about 0.85.
In general, the draft angles formed by the cavity side walls 45 and the lattice 46 of a decking panel 42 are in a range of about 30 degrees to about 60 degrees, preferably in a range of about 35 degrees to about 55 degrees, most preferably in a range of about 40 degrees to about 50 degrees, for example about 45 degrees. In another embodiment of the invention, the draft angle between a side wall 45 and the lattice 46 of a decking panel 42 is greater than 45 degrees. The increased draft angles, especially draft angles greater than about 45 degrees, provide substantial advantages in the decking component 40 of the invention, such as the ability to span greater distances with reduced material cost and increased strength.
The profile thickness of a decking panel 42 (measured by the greatest depth of the decking panel 42, for example, the distance from an upper surface 146 of the lattice 46 to a bottom surface 147 of a cavity floor 47 preferably is in a range of about ¼ inch (about 6.35 mm) to about 8 inches (about 20.32 cm), and more preferably about ¼ inch (about 6.35 mm) to about 4 inches (about 10.16 cm).
The depth of draw is measured as the vertical distance traveled by a side wall 45 between the center lines of a cavity floor 47 and lattice 46. Whereas the depth of draw can be uniform throughout a decking panel 42, this need not be the case. Thus, for example, the cavity floors 47 are preferably, but optionally, in a single plane. The depth of draw preferably is at most about 6 inches (about 15.24 cm), and more preferably in a range of about ¼ inch (about 6.35 mm) to about 3½ inches (about 8.89 cm). In one decking embodiment of the invention, the depth of draw is greater than the caliper of any one of the lattice 46, side wall 45, and cavity floor 47.
The length of a cavity 44, for example the distance between parallel flat zones 46a and 46b preferably is in a range of about 6 inches (about 15.24 cm) to about 90 inches (about 228.6 cm). The width of a cavity 44, measured in the direction perpendicular to the length, preferably is in a range of about 4 inches (about 10.1 cm) to about 24 inches (about 60.9 cm).
Whereas the lattice 46 shown in
In a preferred embodiment of the invention, a consolidated decking panel 42 is bonded with a sheathing panel 43 to form the decking component 40 shown in
A sheathing 43 of the composite decking component 40 preferably is generally planar with a uniform cross-sectional dimension. However, it is to be understood that the invention is also applicable to the use of other sheathing configurations.
Preferably a sheathing 43 has a length and width about equal to the length and width of a corresponding decking panel 42 in the decking component 40.
Floor Components
The inventive process can be used to produce an integrated floor component product of the invention suitable as a replacement for conventional joist and decking flooring, or engineered with dimensions and strength characteristics for specific applications.
Referring to
Wall Components
The inventive process can be used to produce an integrated wall component product of the invention suitable as a replacement for conventional stud and sheathing walls, or engineered with dimensions and strength characteristics for specific applications.
The wall component preferably is made by the same method used to produce the bonded assembly 20 of the composite lumber embodiments. The web 21 of a wall component preferably has a much lower frequency of web segment 36 repeat. In addition, the wall component preferably has one web 21 with a profile depth of about 5½ inches (about 14 cm) to accommodate R-19 insulation in the channels 24 between flanges 23.
Building components made according to the invention such as lumber components, decking components, floor components, walls, posts and framing members exhibit many improved attributes. First, the invention provides consistency in sizing accuracy of building components, both at the time of construction and over the lifespan of the component and structures built therewith. The building components of the invention also require less material input than their conventional lumber and sheathing counterparts. The building components of the invention can weigh less than their conventional lumber and sheathing counterparts. Because the building components of the invention weigh less than their conventional lumber and sheathing counterparts, they can be shipped in larger sizes. Moreover, because the building components of the invention are dimensionally consistent and can be shipped in larger sizes, less labor is required to assemble the components in construction of a building. In addition, the invention can provide a product with increased surface friction to facilitate installation and usage.
Larger distances can be spanned while using fewer supporting members because the building components of the invention can be engineered to be stronger than their conventional lumber counterparts. The composite lumber embodiments of the invention are able to provide built-in voids suitable to accommodate wiring and piping, which eliminates the labor involved in drilling conventional lumber for the same purpose. Moreover, the multi-ply building components of the invention are able to provide built-in voids which increase the thermal and acoustic insulating efficiency of the components. The invention also provides for the ability to engineer building components with built-in properties such as custom pigmentation and resistance to fire, insects, water, UV radiation, and bacteria. The building components of the invention also are environmentally friendly because they allow for more thorough usage of timber, allow for the usage of lower-quality timber, and can be ground up and easily disposed of or reused. Finally, the invention provides for great efficiencies of production whereby many pieces of composite lumber or fully-assembled flooring systems can be produced at once in assembly-line fashion and whereby many of the same operations can be used to produce different building components such as walls, posts, and composite lumber.
The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications within the scope of the invention wilt be apparent to those skilled in the art.
This application is a divisional of application Ser. No. 09/680,115, filed Oct. 5, 2000, now U.S. Pat. No. 6,773,791, which is a CIP of application Serial No. 09/538,766 filed Mar. 30, 2000, now U.S. Pat. No. 6,511, 567, which claims priority to provisional application Ser. No. 60/127,120 filed Mar. 31, 1999 the disclosure of which is incorporated herein by reference and priority to which is claimed pursuant to 35 U.S.C. § 120. This application is a continuation-in-part of U.S. patent application Ser. No. 09/538,766, filed Mar. 30, 2000, which claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application 60/127,120 filed Mar. 31, 1999.
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| Child | 10913525 | US |
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| Child | 09680115 | US |
