Patent Application
20100263315
The present invention relates generally to siding systems, and more specifically to siding systems formed from cementitious slurries, especially those containing gypsum.
Many homes in North America use brick, vinyl siding, aluminum siding, or wood as the material comprising the exterior walls thereof. Brick provides excellent aesthetic, weather protection, and insulation properties, and is virtually maintenance free. However, brick is considerably more expensive to install than the other three primary siding materials due to the high labor costs.
Vinyl siding is made from PVC (polyvinyl chloride) and has begun to be used in construction more and more all the time. Vinyl siding can be fashioned to resemble wood, with the average width of vinyl siding ranging from 6 inches to 10 inches. However, other various lengths and widths are available. Scratches are rarely visible, because the PVC that the siding is composed of is solid all the way through. Vinyl siding is similar in many properties to aluminum, such as weight and density. However, unlike aluminum, vinyl does not dent, and besides aesthetic repair, scratched vinyl siding does not rust and will not ruin the integrity of the siding. Temperature will not affect vinyl siding, which can be installed in nearly any climate. Aluminum siding might take a long time to re-install if damaged, which is untrue of vinyl siding. Vinyl's temperature at which it ignites is very high (736° F.), and it has half the burn time of cedar and burns one third as hard.
Aluminum siding is also one of the most popular exterior home coverings. It is more common than steel siding systems because steel tends to rust when exposed for a long period of time, unlike aluminum. Like vinyl siding, aluminum siding is relatively low-maintenance in its first few years. Aluminum siding comes in long panels, so it takes less time to install. It has baked on enamel that can be flat or shaped to resemble wood grain. Aluminum siding is waterproof, a good insulator, and the most fireproof type of siding. Unfortunately, aluminum siding is susceptible to dents and can be difficult to repair once it's been completely installed. For the first few years, aluminum siding requires little maintenance. However, it soon may show signs of cracking, corrosion, and peeling. After two or three years, the home owner should begin monitoring the aluminum siding for dents and other marks. Eventually, damaged panels should be repainted or replaced, which is a time-consuming and potentially expensive process.
The most common type of siding for a house is wood (e.g., cypress, cedar, redwood, and/or the like) which provides an attractive appearance and good insulation properties. However, as evidenced by the fact that more and more consumers are choosing vinyl, aluminum, and other siding choices, there are a number of drawbacks.
Wood in general is a haven for animals and insects. For example, many woodpeckers and other birds are drawn to the wood on the outside of houses. It is thought that tannin, a resin that is found in cedar is a natural insect repellent. However, the same tannin can cause rain spots that will appear for the first three years that the cedar is on the home. Redwood is much like cedar except that its color is slightly different.
Plywood, which is a common type of siding, is usually composed of western red fir, yellow pine, and Douglas fir. Either roughhewn or smooth, plywood is usually attached to a home horizontally and isn't the best way to protect from water damage. However, plywood is attractive for its natural look, and many ways are being developed to strengthen its structural integrity. Clapboard is simply long boards of wood applied horizontally and overlapping on a house. The result can look uneven and irregular, but beveled or tapered boards can correct this problem. Hardboard or composition board is comprised of compressed wood fiber and adhesives that are weather resistant and applied to planks or sheets of wood to strengthen them and make them more waterproof. Hardboard can measure 16 feet in length, though many people have it cut to better resemble clapboard. Plywood siding is comprised of a veneer, which is a slice of wood of constant thickness, and it is applied to hardwood to form hardwood siding. More durable than indoor plywood, it is also much more waterproof. Rectangular plank siding is comprised of smooth planks that meet each other evenly. When laid vertically, they form a flat surface that is interrupted only by battens designed to keep moisture out. Wood plank siding is very much like rectangular plank siding in that boards are laid vertically and protected from water damage. However, wood plank siding comes in many shapes and can be cut many different ways to give texture and a pattern.
A rustic, pastoral look can be achieved by using shake siding, which is made up of hand-split, irregular cedar sidings. They are rough and either put on all at once or in layers to use weathering as an effect for patterns. They are susceptible to cracking, warping and curling, so they should be checked often and replaced when necessary. Unlike shakes, sidings are machine cut, smooth and uniform. They are increasingly overlapped as they are higher on the house, however many people create their own patterns and decide the degree to which there is an overlap. Like shakes, sidings can fall victim to warping, cracking, and curling.
Any wood siding product, but especially less protected wood like shakes and sidings, should be kept away from moisture and protected from the elements. Typically this involves the regular application of stains, sealants, and paints, and is generally an expensive and time-consuming process. Failure to properly maintain the wood siding product can lead to irreparable damage and potential rotting of the wood, necessitating expensive repairs.
A recent product in the siding market has been asbestos-free fiber-cement siding. Its market share is on the rise, but it still lags behind wood and vinyl siding. Fiber-cement siding generally is more expensive than aluminum or vinyl siding, but it costs less than brick or traditional cedar siding. It is sold under a number of brand names, including HARDIPLANK, CEMPLANK, and WEATHERBOARDS. To make the siding, manufacturers mix cement, sand and cellulose fibers with water. The planks are offered in various widths in both horizontal and vertical styles. They can be given a smooth look or finished with a heavier wood grain appearance. James Hardie Building Products, which makes the HARDIPLANK line, has introduced a plank that simulates the look of sidings to use as an accent on a home. A big selling point of fiber-cement siding is that it offers a number of benefits over wood. For example, this siding resists damage from the elements and insects, and provides very good structural strength and good impact resistance. From a safety standpoint, the fiber-cement siding itself won't burn, but the finishing materials (e.g., paints) applied thereto might. Although makers of the fiber-cement siding tout its low-maintenance qualities, it does, as noted, need to be painted periodically. Attaching fiber-cement siding to a home is similar to applying wood siding; however, this type of siding is heavier, more difficult to cut, and generally more difficult to install than traditional siding materials.
Another recent development in siding products is molded reinforced cementitious siding. Such siding is comprised of cement, or a cementitious exterior shell at least partially enveloping an optional foam core, wherein the cementitious materials especially contain gypsum (e.g., calcined gypsum). The siding system members are formed from cementitious slurry comprising gypsum cement (e.g., calcined gypsum) and a latex/water mixture. The slurry can also contain other materials, such as but not limited to reinforcement materials (e.g., fibers, scrims, netting, meshes, and/or the like), as well as other materials that are known in the art (e.g., activators, set preventers, plasticizers, fillers, and/or the like), which can be added before and/or after the combination of the gypsum and latex/water mixture. The slurry is introduced into the mold over a previously-inserted meshed reinforcement material, such as a fiberglass mat. The slurry impregnates and envelops the mat, which adds considerable flexibility to the resulting product without it breaking, as would occur in a product formed only of the hardened slurry, even with the inclusion of aggregate reinforcement materials contained in the slurry. Even with the flexing capabilities afforded with meshed or matted reinforcement materials, such siding members can be difficult to handle in long lengths (e.g., of several feet in length), which are typically used in many siding applications where wood siding is simulated.
This is in part due to a lack of member rigidity, which is overcome in part by the inclusion of a foam core. But another factor contributing to this handling problem stems from supporting elongate cementitious members at perhaps only one or two localized positions along its length, which can impart significant bending stresses in the cementitious material, at or between the localized support location(s), where bending is greatest. The bending moment acting on a member at these high stress sites typically result from the member being supported only at or near the midpoint of its length, or being supported only at or near its opposite ends. This is particularly problematic when the planar member is supported in a substantially horizontal orientation.
Therefore, it would be advantageous to provide durable and economical siding systems, and methods for forming the same, which overcome at least one of the aforementioned problems.
The present invention provides a siding member, and methods for forming the same, wherein the siding member includes an integrally-formed I-beam construction. The siding member may be formed in a mold from cementitious slurry comprising gypsum cement (e.g., calcined gypsum) and a latex/water mixture, or comprising hydraulic cement. The slurry can also contain other materials, such as but not limited to reinforcement materials (e.g., fibers, scrims, netting, meshes, and/or the like), as well as other materials that are known in the art (e.g., activators, set preventers, plasticizers, fillers, and/or the like), which can be added before and/or after the combination of the gypsum and latex/water mixture, or mixing of the hydraulic cement. The present invention also provides an alternative continuous method for producing relatively long lengths of the siding that can be cut to an appropriate size, without the need to produce individual siding members of limited size.
The slurry is introduced into the mold or molding system over a plurality of parallel, longitudinal elements that substantially lie in a plane and extend substantially the entire length of the siding member being formed. These elements, referred to herein as “core” or “void producing” elements, which may remain in the finished product, need not themselves provide appreciable structural support to the siding member, but rather serve primarily to displace the cementitious slurry such that the slurry forms, when cured, an integral structure providing a plurality of adjacent, integrally-formed webs extending along the thickness of the siding member. In cross section, normal to the member's longitudinal axis, one or both of the opposite ends of each web portion is an integrally-formed flange portion that is merged or integrally joined with an adjacent such flange below the surface of at least the exterior face of the siding member, thus providing the siding member with an integrally-formed I-beam construction. Such a structure provides the siding member with an increased moment of inertia that increases siding member rigidity and its resistance to bending. Moreover, because cementitious material is displaced by the core elements, less of the cementitious material is used in each siding member, thereby decreasing the weight of the siding member and, depending on the materials used, its direct variable cost. This weight reduction also reduces indirect variable cost, in terms of fuel to transport the siding, and makes the siding easier to handle. Moreover, because of its increased rigidity and resistance to bending, as well as its relatively reduced weight, the individual siding members may be handled with reduced risk of breakage due to supporting it at perhaps only one or two localized positions along its length, even when being supported in a substantially horizontal orientation.
The core or void-producing elements located between the webs, which establish the longitudinally-extending webs and flanges internal to the siding member may be of any suitable and convenient material, structure or cross-sectional shape, such as but not limited to square or cylindrical foam backer rod, or thin-walled cylindrical plastic or paper tubing (much like a soda straw), and need not be adhered to the cementitious material in the final product. Indeed, the elements may degrade over time, leaving only a longitudinally extending channel or void in the cementitious siding material, although it is preferable that the elements not be of a material that would promote the growth of mold within the siding member. Alternatively, the core or void-producing elements may be integrated into an upper mold surface member that is interfitted to a lower mold surface member to form a closed mold into which the slurry is injected.
Maintaining the orientation of longitudinal elements that remain with the finished product prior to and during the molding process may be facilitated by an optional meshed scrim material to which is sprayed or otherwise applied an adhesive material. The longitudinal elements are distributed in parallel on the scrim fabric, and held in position thereon by the adhesive. Preferably, relative to the plane defined by the arrangement of core elements, the scrim material is located on the side on which the exposed, exterior face of the siding member will be formed, thereby improving the resistance of the exposed, molded siding surface to cracking due to any deflection of the siding member. The cementitious slurry is applied over the core elements and scrim, and flows through the scrim, to a desired depth that covers and encapsulates the scrim and the core elements.
Certain embodiments of the inventive siding and molding processes optionally provide at least one, and preferably a plurality of longitudinally extending support portions that extend substantially the entire length of each molded siding member. The fibers are immersed in the slurry and, once the slurry cures or hardens, are captured by the cementitious material and substantially prevented from moving relative thereto. The fibers may be tensionally prestressed such that in the resulting siding member, the fibers are under tension in the siding member's natural, undeformed state. Alternatively, the fibers may be subjected to tensile stresses only upon bending deformation of (or tension forces being exerted on) the siding member. The tensioned fibers aid in resisting bending deformation of the siding member, and places the siding member in a longitudinally directed compression, thereby reinforcing it against cracking or breaking, much as steel rebar does in reinforced concrete structures. Such siding and processes for its manufacture are taught in U.S. patent application Ser. No. 12/689,368 filed Jan. 19, 2010, by J. Richard Logan, et al. entitled MOLDED SIDING HAVING LONGITUDINALLY-ORIENTED REINFORCEMENT FIBERS, AND SYSTEM AND METHOD FOR MAKING THE SAME, the complete disclosure of which is expressly incorporated herein by reference.
The slurry can contain colorants dispersed therethrough, or alternatively, the mold surface that forms the exposed, exterior siding member surface can be coated with a colorant. In addition to the above-mentioned scrim and longitudinally-oriented fibers, a fabric of reinforcement material (e.g., fiberglass netting or mat, and/or the like) can be optionally added to the mold. Further, during one or more of the aforementioned stages, the mold or molding system can be vibrated and/or force/pressure applied. After an appropriate curing or drying time, the product (e.g., a molded siding member) is removed from the mold system and is ready for immediate use and/or further processing.
The present invention provides a siding system including at least one elongate member molded of cementitious material and having opposed front and back sides, the front side formed of cementitious material and having a front exterior face located on one side of an imaginary plane, the member including a plurality of longitudinally-oriented support portions that extends substantially the entire length of the member. Each support portion has a web portion that extends in a direction substantially normal to the plane and at least one flange portion, the webs of adjacent support portions separated by a longitudinally-oriented void in the cementitious material and located in the plane. Flange portions located on the same side of the plane as the member front side are integrally connected to each other. The support portions are subjected to compressive and tensile stresses during bending deformation of the member out of the plane, and the bending deformation of the member is resisted by the support portions.
The present invention also provides a molding system for forming an elongate siding member comprising a cementitious material that defines a plurality of longitudinally oriented support portions extending substantially the entire length of the siding member and longitudinally oriented voids in the cementitious material. The system includes a mold face defining at least a portion of a front exterior surface of the siding member, means for orienting void-producing elements relative to the mold face, and a cementitious material source from which a desired amount of cementitious material is received onto the mold face and at least partially envelops the void-producing elements.
The present invention also provides a method of molding an elongate siding member comprising cementitious material having a plurality of integrally-formed longitudinally oriented cementitious material support portions which extends substantially the entire length of the siding member, including the steps of: longitudinally-orienting void-producing elements over a mold face; receiving cementitious material onto the mold face; at least partially surrounding the void-producing elements with the cementitious material received onto the mold face; forming a front exterior surface of the siding member and a plurality of integrally-formed longitudinally-oriented support portions which extends substantially the entire length of the siding member from the cementitious material received onto the mold face; curing the formed cementitious material; and separating the siding member and the mold face.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposed of illustration only and are not intended to limit the scope of the invention.
Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
It is to be noted that the Figures are not drawn to scale. In particular, the scale of some of the elements of the Figures is greatly exaggerated to emphasize characteristics of the elements. It is also noted that the Figures are not drawn to the same scale. Elements shown in more than one Figure that may be similarly configured have been indicated using the same reference numerals.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and may herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, or uses. It is to be noted that the Figures are not drawn to scale. In particular, the scale of some of the elements of the Figures is greatly exaggerated to emphasize characteristics of the elements. It is also noted that the Figures are not drawn to the same scale. Elements shown in more than one Figure that may be similarly configured have been indicated using the same reference numerals.
Referring to the Figures generally, and specifically to
The siding system 10 can be mounted, either permanently or temporarily to a dwelling, such as a residential or commercial building.
With specific reference to
It should be appreciated that the siding members of both siding systems 10, 10a can be cut (e.g., with a circular saw, table saw, tile saw, and/or the like) to desired length, but the integrally formed I-beam construction of the siding members as described below permits their installer and others to more easily handle them in long lengths (i.e., of several feet in length) with substantially reduced risk of the molded cementitious siding members breaking or cracking. As shown, siding systems 10, 10a of the present invention can include surface textures 16, 16a, respectively, on at least the front exterior face 18 of the siding member to mimic the look of wood grain or any other type of material. Additionally, the siding systems 10, 10a of the present invention can be installed in any number of patterns, e.g., the ground level can include siding system 10 and the second level or eaves can include siding system 10a.
The siding members 12, 12a have opposed front and back sides, with the front side having exposed, front exterior surface 18. The siding members include a plurality of longitudinally-oriented support portions 20 integrally formed of cementitious material that extend substantially the entire member length and through the siding member thickness. Voids 22 located between adjacent webs 24 of support portions 20 may be spaced at approximately ½ inch from each other, center to center, and lie in a plane 26 substantially coinciding with a plane defined by the illustrated siding member. In the description that follows, “void” shall refer to the space 22 between adjacent webs 24 whether completely hollow or devoid of any material, or filled with a core or void-producing element 28 made from other than cementitious material. Front exterior face 18 lies on one side of plane 26, and when the siding member is in a natural, undeformed state, may be substantially parallel therewith. Web portions 24 extend in a direction substantially normal to plane 26.
Core or void-producing elements 28 are generally elongate members such as, for example, foam backer rods or thin-walled tubes (generally resembling drinking or soda straws) which are, in some embodiments, encapsulated by cementitious material, and are carried by and remain in the finished product. The void-producing elements themselves provide no substantive resistance against deflection of siding members 12, 12a, and need not be joined (as through bonding adhesion, for example) to the cementitious material of the siding member. The purpose of the void-producing elements is to displace cementitious material in the siding member, to form voids 22 in the cementitious material that define web portions 24 of adjacent support portions 20. Core elements 28 may be substantially flexible, or semi-rigid, thereby facilitating the siding member's ability to be flexed to a minor degree to conform to surfaces in the ordinary manner of various siding types. That is, a certain degree of flexibility in the siding members to facilitate its installation on building sheathing, for example, is desirable.
Alternatively, certain embodiments of processes and systems for forming siding members in accordance with the present invention may incorporate the core or void-producing elements into an upper mold surface member that forms the reverse surface of the siding member, the core elements so incorporated into the upper mold surface member being configured to produce the siding member support portions. In such embodiments, webs 24, and spaces or voids 22 therebetween, define the profile of the formed siding member's reverse surface 30, whereas its exterior surface 18 remains substantially as shown in
The siding members 12, 12a optionally include a reinforcement fabric 50, such as but not limited to fibers, scrims, netting, meshes, and/or the like, that can be added during formation or manufacture of the siding members 12, 12a, but are generally referred to as “meshed” reinforcement materials. Meshed reinforcement fabric 50 may be, for example, continuous strand natural fiberglass mat having a weight of approximately 0.75 ounce per square foot. Moreover, the siding members optionally include one or a plurality of longitudinally-oriented reinforcement fibers as described in above-mentioned U.S. Provisional Patent Application No. 61/145,592.
Referring to
The cementitious slurry is also permitted to infiltrate through the various crevices, apertures, or spaces, if present, formed in the meshed reinforcement fabric 50, if present, such that the meshed reinforcement fabric 50 is completely surrounded and enveloped by the cementitious slurry. The meshed reinforcement fabric 50 can aid in imparting increased strength, fracture resistance, and/or a desired degree of flexibility to the siding members 12, 12a.
Referring to
In accordance with one aspect of the present invention, the siding member 12, 12a, apart from the core void-producing elements 28 and the optional reinforcement fabric 50 and/or scrim 52, is substantially formed from the cementitious slurry. The slurry can include hydraulic cement including, but not limited to, Portland, sorrel, slag, fly ash, or calcium alumina cement. Additionally, the cement can include a calcium sulfate alpha hemihydrate or calcium sulfate beta hemihydrate. The slurry can also utilize natural, synthetic, or chemically modified beta gypsum or alpha gypsum cement.
The cementitious slurry preferably includes gypsum cement and a sufficient amount of water added thereto to produce a slurry having the desired consistency, i.e., not too dry nor not too watery. In accordance with one aspect of the present invention, the water is present in combination with a latex material, such that the powdered gypsum material is combined with the latex/water mixture to form the cementitious slurry.
Gypsum is a naturally occurring mineral, calcium sulfate dihydrate, CaSO4.2H2O (unless otherwise indicated, hereafter, “gypsum” will refer to the dihydrate form of calcium sulfate). After being mined, the raw gypsum is thermally processed to form a settable calcium sulfate, which can be anhydrous, but more typically is the hemihydrate, CaSO4.½H2O, e.g., calcined gypsum. For the familiar end uses, the settable calcium sulfate reacts with water to solidify by forming the dihydrate (gypsum). The hemihydrate has two recognized morphologies, alpha and beta hemihydrate. These are selected for various applications based on their physical properties. Upon hydration, alpha hemihydrate is characterized by giving rise to rectangular-sided crystals of gypsum, while beta hemihydrate is characterized by hydrating to produce needle-shaped crystals of gypsum, typically with large aspect ratio. In the present invention, either or both of the alpha or beta forms can be used, depending on the mechanical performance required. The beta form generates less dense microstructures and is preferred for low density products. Alpha hemihydrate could be substituted for beta hemihydrate to increase strength and density or they could be combined to adjust the properties.
The cementitious slurry can also include other additives. The additives can include, without limitation, accelerators and set preventers or retarders to control the setting times of the slurry. For example, appropriate amounts of set preventers or retarders can be added to the mixture to increase the shelf life of the resulting slurry so that it does not cure prematurely. When the slurry is to be used in molding operations, a suitable amount of an accelerator can be added to the slurry, either before or after the pouring operation, so as to increase the drying and/or curing rate of the slurry. Suitable accelerators include aluminum sulfate, potassium sulfate, and Terra Alba ground gypsum. Additional additives can be used to produce colored siding systems 10, 10a, such as dry powder metallic oxides such as iron and chrome oxide and pre-dispersed pigments used for coloring latex paints.
In accordance with one aspect of the present invention, the cementitious slurry includes a gypsum cement material, such as but not limited to calcined gypsum (e.g., calcium sulfate hemihydrate), also commonly referred to as plaster of Paris. One source of a suitable gypsum cement material is readily commercially available from United States Gypsum Company (Chicago, Ill.) and is sold under the brand name HYDROCAL® FGR 95. According to the manufacturer, HYDROCAL® FGR 95 includes more than 95 wt. % plaster of Paris and less than 5 wt. % crystalline silica.
The gypsum cement material should include an approximate 30% consistency rate. That is, for a 10 lb. amount of gypsum cement material, approximately 3 lbs. of water of would be needed to properly activate the gypsum cement material. If a latex/water mixture is being used to create the cementitious slurry, and the mixture contains approximately 50 wt. % latex solids, then approximately 6 lbs. of the latex/water mixture would be needed, as the latex/water mixture only contains approximately 50 wt. % water, the remainder being the latex solids themselves.
In accordance with another aspect of the present invention, the cementitious slurry includes a melamine resin, e.g., in the dry form, which acts as a moisture resistance agent. The melamine resin is present in an amount of about 10% of the weight of the gypsum cement material. For example, if 10 lbs. of gypsum cement material are used, then approximately 1 lb. of the melamine resin would be used. One source of a suitable melamine resin is readily commercially available from Ball Consulting Ltd. (Ambridge, Pa.).
In accordance with still another aspect of the present invention, the cementitious slurry includes a pH adjuster, such as but not limited to ammonium chloride, a crystalline salt, which acts to ensure proper cross-linking of the latex/water mixture with the dry ingredients, especially the melamine resin. The ammonium chloride is present in an amount of about 1% of the weight of the gypsum cement material. For example, if 10 lbs. of gypsum cement material are used, then approximately 0.1 lbs. of the ammonium chloride would be used. One source of a suitable ammonium chloride is readily commercially available from Ball Consulting Ltd. (Ambridge, Pa.).
In accordance with yet another aspect of the present invention, the cementitious slurry includes a filler such as but not limited to fly ash (e.g., cenosphere fly ash), which acts to reduce the overall weight and/or density of the slurry. The fly ash is present in an amount of about 30% of the weight of the gypsum cement material. For example, if 10 lbs. of gypsum cement material are used, then approximately 3 lbs. of the fly ash would be used. One source of a suitable fly ash is readily commercially available from Trelleborg Fillite Ltd. (Runcorn, England).
Several of the wet and/or dry components of the cementitious slurry of the present invention are readily commercially available in kit form from the United States Gypsum Company under the brand name REDI-ROCK®. Additional information regarding several suitable components of the cementitious slurry of the present invention can be found in U.S. Pat. No. 6,805,741, the entire specification of which is expressly incorporated herein by reference.
One or more of the dry ingredients are to be combined with the liquid portion of the cementitious slurry, i.e., the latex/water mixture. If the latex/water mixture includes 50 wt. % latex solids, with the rest being water, then the latex/water mixture is present in an amount of about 60% of the weight of the gypsum cement material. For example, if 10 lbs. of gypsum cement material are used, then approximately 6 lbs. of the latex/water mixture would be used. One source of a suitable latex/water mixture is readily commercially available from Ball Consulting Ltd. (Ambridge, Pa.) under the brand name FORTON® VF-812. According to the manufacturer, FORTON® VF-812 is a specially formulated, all acrylic co-polymer (50% solids) which cross links with a dry resin to make the system moisture resistant and UV stable.
The resulting cementitious slurry of the present invention should possess the following attributes: (1) it should stay wet or flowable for as long as possible, e.g., days, weeks, months, as circumstances warrant; (2) it should self level, i.e., the slurry should level by itself without intervention from the user when introduced into or onto a mold face surface; and (3) it should contain a limited water content (e.g., compared to conventional gypsum cement slurries), i.e., it should not be so wet so as to take a very long time (e.g., several hours or even days) to dry or cure.
Alternatively, the slurry can be created on demand, as needed from a water and dry components mixed therewith, avoiding the need to store a mixed volume of cementitious slurry.
Alternatively, the cementitious slurry can be a mixture of rapidly setting hydraulic cement (not a Portland cement) that may or may not contain fiberglass fillers. RapidSet Construction Cement manufactured by CTS Cement Manufacturing Corp. of Cypress, Calif. (www.RapidSet.com) is an acceptable alternative to the above-discussed Gypsum/Latex material, although it is somewhat more brittle and sets in a short time, necessitating its being mixed in rather small batches that can be quickly used. This hydraulic cement is, however, much cheaper than the Gypsum/Latex mixture, and bonds better to fiberglass.
In accordance with one aspect of the present invention, a reinforcing material can also be disposed within the cementitious slurry, either prior to or after the introduction of the water thereto. The reinforcing material can include, without limitation, fibers, e.g., either chopped or continuous fibers, comprising at least one of polypropylene fibers, polyester fibers, glass fibers, and/or aromatic polyamide fibers. By way of a non-limiting example, the reinforcing material can include a combination of the fibers, such as the polypropylene fibers and the glass fibers or the polyester fibers and the glass fibers or a blend of the polypropylene fibers and the polyester fibers and the glass fibers. If included in the fiber composition, the aromatic polyamide fibers are formed from poly-paraphenylene terephthalamide, which is a nylon-like polymer commercially available as KEVLAR® from DuPont of Wilmington, Del. Of course, aromatic polyamide fibers other than KEVLAR® are suitable for use in the fiber composition of the present invention.
The cementitious slurry can then be mixed, either manually or automatically, so as to adequately combine the various ingredients thereof and optionally can also be agitated, e.g., by a vibrating table, to remove or lessen any air bubbles that formed in the cementitious slurry.
Referring to
With specific reference to
The mold surface member 204 or 204a can be formed of any type of material, such as rigid or flexible materials; however, preferably the mold surface member 204 or 204a is formed from a suitably flexible material that, e.g., can be removed from the cavity 206 (e.g., rubber, silicone, urethane and/or the like). The respective face 208 or 208a of the mold surface member 204 or 204a is essentially a negative image of the desired front and/or side exterior surface shape of the siding member 12 or 12a. Additionally, the mold surface member 204 or 204a preferably includes a peripheral lip member 210 (
Although the following description will be directed primarily toward the production of siding member 12, it should be understood that the methodologies disclosed herein are equally applicable to the production of siding member 12a (provided that mold surface member 204a having face 208a is employed).
Referring specifically to
As previously noted, in order to provide siding member 12 of various colors to satisfy consumer demand, the cementitious slurry can contain colorants dispersed therethrough, or alternatively, the face 208 of the mold surface member 204 can be coated with a colorant, or in the case of a “natural cedar shake” effect, a series of colorants can be provided to produce a multi-colored and/or variegated siding member 12. Furthermore, it should be noted that paints, stains, sealants, and/or the like can also be applied to the face 208 of the mold surface member 204 before the introduction of the cementitious slurry, or alternatively, they can be applied to the finished product after removal from the mold surface member 204. This process can be done in a factory setting or at a worksite, by either the installer or the homeowner.
Referring specifically to the embodiments depicted in
Mold surface member 204 having been placed in cavity 206 of support 202, reinforcement fabric 50 is optionally placed in the mold surface member 204, and if so preferably in proximity to the face 208 of the mold surface member 204. Because it is desired that the cementitious slurry be allowed to infiltrate through the meshed reinforcement fabric 50, if used, it is desirable to leave a space between the meshed reinforcement fabric 50 and the face 208 of the mold surface member 204 such that the flowing cementitious slurry can fill the area therebetween and prevent any “read through” of the meshed reinforcement fabric 50 on the finished surface of the siding member 12.
Optionally, one or more longitudinally-oriented reinforcement fiber bundles may be incorporated into the process and molded product as described in above-mentioned U.S. Provisional Application Ser. No. 61/145,592.
Referring to
In the open mold system 200, a means for orienting void-producing elements relative to the mold face 208 includes placement of elements 28 manually or through use of a suitable positioning jig or gage (not shown), onto the mold face 208 or onto the optional reinforcement material fabric 52.
Referring specifically to
It is to be understood that the above-described processes are but examples of how longitudinally-oriented core elements 28 might be arranged for molding siding member 12 in a substantially open molding or casting process. Any suitable method for longitudinally arranging core elements 28 within the mold to effect the formation of support portions 20 in siding member 12 may be alternatively employed, including, for example, employing an upper mold surface member that is interfitted with lower mold surface member 204 to form and arrangement of longitudinally extending voids 22 and webs 24 in reverse face 30 of the molded siding member, although defining a siding member reverse face that is other than substantially flat. Referring to
Closed mold system 250, which utilizes mold retainer support 202 and lower mold surface member 204 substantially as described above, preferably in conjunction with conveyor system 350, but which also includes upper mold surface member 260 interfitted with lower mold surface member 204, is used in an injection molding process. Upper mold surface member 260 includes sprue 262 through which the slurry is introduced to the closed mold. Referring to
In the closed mold system 250, a means for orienting void-producing elements relative to the mold face 208 includes the arrangement of void-producing elements 228 provided on the mold surface of upper mold surface member 260 which is placed into operative engagement with lower mold surface member 204 during injection of the cementitious material slurry.
Regardless of whether a siding member is formed by an open molding or casting process utilizing system 200, or an injection molding process utilizing closed mold system 250, the cementitious slurry is then allowed to dry, harden or cure for a sufficient amount of time, which may depend, at least in part, on the specific composition of the cementitious slurry used. The mold system 200 or 250 can also be shuttled off of the conveyor system 350 and stored in a storage area (not shown) so that other siding systems 10 can be made in the interim.
Referring specifically to
Referring now to
Initially, parallel continuous lengths of parallel core elements 28, preferably spaced about ½ inch apart, are fed via core element feed roller system 302 onto the surface 310c of bottom roller system 310. Roller 302a may be provided with rotational resistance to provide a desired amount of drag on core elements 28 wound thereabout, and a sufficient amount of tensile stress in core element 28 as may be required for providing a pulling force on the core element leading ends to take up slack and set the core elements 28 into the molding process. Once the process has begun, however, the cementitious material of the siding product exiting system 300 will have sufficiently cured to capture the core elements 28 being received into system 300, and exert the necessary pulling force on the core elements 28 being unwound from roller 302a to eliminate any slack in the core elements.
An appropriate amount of the cementitious slurry is placed onto the core elements via the cementitious slurry feed system 304. The slotted roller 306 (or other appropriate roller or other device) rotates over the cementitious slurry to maintain the appropriate position of core elements 28 relative to the thickness of the siding member 12. Slotted roller 306 ensures core elements 28 are immersed into and enveloped by the slurry. Notably, slurry feed system 304 could alternatively be located downstream of slotted roller 306a.
As the cementitious slurry/core elements 28 combination travels through the top roller system 308 and bottom roller system 310, with core elements 28 maintained in tension sufficient to at least prevent any slack therein, the cementitious slurry is contacted by a textured face 310d formed on the surface 310c of belt 311 of the bottom roller system 310. The textured face 310d includes a pattern that is operable to impart the appropriate siding pattern onto the adjacent surface of the cementitious slurry. The finished siding system then passes out through the top roller system 308 and bottom roller system 310 and can be cut by an optional cutting device 312 (e.g., a transverse saw) into siding systems of appropriate length. The cut siding members 12 received from the outlet of system 300 can be fed onto an optional conveyor system 314 for packaging or shipment purposes.
In continuous molding system 300, a means for orienting void-producing elements relative to the mold face 310c includes feed roller system 302, and the cementitious slurry which pulls the parallel lengths of core element 28 therefrom, and positions them relative to the mold face.
Alternatively, in continuous molding system 300, a means for orienting void-producing elements relative to the mold face 310c upper roller system may include a belt 309 on the outer surface of which is formed a plurality of longitudinally extending parallel ribs (not shown), which can be used instead of void-producing element feed roller system 302 and encapsulated elements 28, which may be omitted. Such an alternative system 300 yields a continuously-formed siding member having reverse surface that is laterally undulating, or longitudinally ribbed, similar to that of above-described member 212; that is, having a reverse surface defined by a plurality of longitudinally oriented web portions and voids therebetween, and revealed when the cured siding is separated from belt 309.
Referring now to
As with the system 300 depicted in
However, in this embodiment, a continuous length of reinforcement fabric 50 is fed via fabric feed system 402 (including rollers 402a and 402b) onto surface 310c of bottom roller system 310.
As described above, reinforcement fabric 50 may be, or be in addition to, scrim 52. If in addition to scrim 52, an additional feed roller system (not shown) would be added upstream or downstream of feed roller system 402 for either reinforcement fabric 50 or scrim 52, as would be understood by one of ordinary skill in the art. Further discussion of system 400 below relates to fabric 50 being scrim 52.
As noted above, scrim 52 preferably has an adhesive applied thereto, as via a suitable known roller applicator or sprayer positioned at 404, is fed via fabric feed system 402 (including rollers 402a and 402b) onto surface 310c of bottom roller system 310, the core elements 28 being affixed to the scrim to ensure their proper positions are maintained through out the molding process, and consequently in the finished product.
As the cementitious slurry/scrim 52/core element 28 combination travels through the top roller system 308 and bottom roller system 310, the cementitious slurry is contacted by a textured face 310d formed on the surface 310c of the bottom roller system 310. The textured face 310d includes a pattern that is operable to impart the appropriate siding pattern onto the adjacent surface of the cementitious slurry. The finished siding system then passes out through the top roller system 308 and bottom roller system 310 and can be cut by an optional cutting device 312 (e.g., a transverse saw) into siding systems of appropriate length, whereupon the cut siding systems can be fed onto an optional conveyor system 314 for packaging or shipment purposes.
In system 400, roller 306 may be modified to ensure that the slurry is forced through scrim 52 and reaches surface 310c of bottom roller system 310, whereby scrim 52 is immersed and encapsulated by the slurry. Notably, with the addition of scrim 52, providing a separate pulling force on core elements 28, or relying on the partially cured slurry to capture the core elements 28, in order to eliminate slack therein can be eliminated in favor of initially feeding scrim 52 into the molding system, adhering the core elements 28 to the scrim with the adhesive applied thereto, and relying on scrim 52 being pulled by the partially cured slurry through system 400. Thus, the adherence of core elements 28 to scrim 52 will provide sufficient tension in the core elements 28 to eliminate any slack in the parallel core element lengths.
In continuous molding system 400, a means for orienting void-producing elements relative to the mold face 310c includes feed roller system 302, and the cementitious slurry and/or the reinforcement material fabric 52 with adhesive applied, which pulls the parallel lengths of core element 28 from feed roller system 302 and positions them on the mold face.
Alternatively, in continuous molding system 400, a means for orienting void-producing elements relative to the mold face 310c upper roller system may include a belt 309 on the outer surface of which is formed a plurality of longitudinally extending parallel ribs (not shown), which can be used instead of void-producing element feed roller system 302 and encapsulated elements 28, which may be omitted. Such an alternative system 400 yields a continuously-formed siding member having reverse surface that is laterally undulating, or longitudinally ribbed, similar to that of above-described member 212; that is, having a reverse surface defined by a plurality of longitudinally oriented web portions and voids therebetween, and revealed when the cured siding is separated from belt 309.
Systems 300 and 400 and their respective processes may be further modified to optionally provide their resultant molded siding members with one or a plurality of longitudinally-oriented reinforcement fibers as described in above-mentioned U.S. Provisional Patent Application No. 61/145,592.
Referring to
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed herein, but that the invention will include all embodiments falling within the scope of the appended claims.
This application claims priority to U.S. Provisional Application No. 61/170,180 filed Apr. 17, 2009, the complete disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61170180 | Apr 2009 | US |
