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Publication numberUS20030079438 A1
Publication typeApplication
Application numberUS 10/016,456
Publication dateMay 1, 2003
Filing dateNov 1, 2001
Priority dateNov 1, 2001
Publication number016456, 10016456, US 2003/0079438 A1, US 2003/079438 A1, US 20030079438 A1, US 20030079438A1, US 2003079438 A1, US 2003079438A1, US-A1-20030079438, US-A1-2003079438, US2003/0079438A1, US2003/079438A1, US20030079438 A1, US20030079438A1, US2003079438 A1, US2003079438A1
InventorsRodney Stephens, Harrel Stocking
Original AssigneeHousing Technology, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Precast modular building panel and vertically oriented method of manufacturing same
US 20030079438 A1
Abstract
A molded composite construction panel formed in a vertically oriented continuous molding procedure included a lightweight cellular core of rigid foam material and a relatively thin skin of fiber reinforced concrete encasing the core. The panel further including at least one integrally formed multi-faceted channel being substantially coextensive with at least one edge of the panel. A method of forming a building panel is also disclosed comprising the steps of providing a mold having a mold cavity, disposed vertically, that defines the mold surface for forming the exposed finish surfaces of a molded wall panel, where the mold cavity bottom and side edge walls define the edge walls of the molded wall panel. A foam insert is positioned and secured in the mold cavity. A slurry of concrete, sand, and fiber strands is formed to produce a homogeneous panel mixture. The mold cavity is filled with the panel mixture. Once cured, the integral assembly of cured panel mixture and foam insert is removed from the mold cavity.
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Claims(47)
What is claimed is:
1. A molded composite construction panel formed in a vertically oriented continuous molding procedure comprising:
A lightweight cellular core of rigid foam material;
A relatively thin skin of glass fiber reinforced concrete encasing said core,
Said panel further including at least one integrally formed channel being substantially coextensive with at least one edge of said panel.
2. A panel as in claim 1 wherein said channel is at least partially arcuate in cross-section.
3. A panel as in claim 1 wherein said channel is multi-faceted in cross-section.
4. A panel as in claim 3 wherein said multi-faceted channel is semi-hexagonal in cross-section.
5. A panel as in claim 1 wherein said relatively thin skin of glass fiber reinforced concrete has about {fraction (1/16)} to inch thickness.
6. A panel as in claim 1 further comprising:
Electrical raceway means embedded within said panel during the molding procedure with respective raceways being adapted for interconnection upon securement of said panel to form an internal electrical raceway network.
7. A panel as in claim 6 wherein said panel is further provided with recess means in communication with said raceway, said recess means being adapted for receiving an electrical junction box.
8. A panel as in claim 1 further comprising raceway means embedded within said panel during the molding procedure with the respective raceways being adapted for interconnection upon securement of said panel to form an internal raceway network.
9. A panel as in claim 1 further comprising:
a channel, integrally formed in the side of said panel, being adapted for receiving raceway means therein.
10. A molded composite construction panel formed in a vertically oriented, continuous molding procedure, comprising:
a light-weight cellular core of rigid foam material with chamfered corners;
a relatively thin skin of fiber reinforced concrete encasing said core,
said panel further including connection means for securing adjacently placed panels.
11. A panel as in claim 10 wherein said connection means comprises:
At least one multi-faceted channel integrally formed in and substantially coextensive with at least one edge of said panel.
12. A panel as in claim 10 wherein said connection means comprises:
A multi-faceted channel integrally formed in and substantially coextensive with each side edge of said panel.
13. A panel as in claim 10 wherein said multi-faceted channel is semi-polygonal in cross-section.
14. A panel as in claim 13 wherein said at least one integrally formed multi-faceted channel is semi-hexagonal in cross-section.
15. A panel as in claim 10 wherein said relatively thin skin of fiber reinforced concrete has about {fraction (1/16)} to inch thickness.
16. A panel as in claim 10 further comprising:
Electrical raceway means embedded within said panel during the molding procedure with respective raceways being adapted for interconnection upon securement of said panel to form an internal electrical raceway network.
17. A panel as in claim 16 wherein said panel is further provided with recess means in communication with said raceway, said recess means being adapted for receiving an electrical junction box.
18. A panel as in claim 10 further comprising water conduit means embedded within said panel during the molding procedure with the respective conduits being adapted for interconnection upon securement of said panel to form an internal water conduit network.
19. A panel as in claim 10 further comprising:
a channel, integrally formed in the side of said panel, being adapted for receiving conduit means therein.
20. A molded composite construction panel formed in a vertically oriented, continuous molding procedure, comprising:
a light-weight cellular core of rigid foam material;
a skin of fiber reinforced concrete encasing said core and having a thickness of about {fraction (1/16)} to about of an inch,
said panel further including at least one semi-hexagonal channel integrally formed in, and substantially coextensive with, at least one side of said panel.
21. A method of forming a building panel, comprising the steps of:
providing a mold having a mold cavity, disposed vertically, that defines the mold surface for forming the exposed finish surface of a molded wall panel, where the mold cavity bottom and side edge walls define the edge walls of the molded wall panel;
positioning and securing a foam insert in said mold cavity;
forming a slurry of concrete, sand, and reinforcing fiber strands to produce a homogeneous panel mixture;
filling said mold cavity with said panel mixture and leveling said panel mixture with the mold side edge walls;
effecting the cure of said panel mixture in said mold and the bonding of said mixture to said foam insert; and,
removing the integral assembly of cured panel mixture and foam insert from said mold cavity.
22. A method of forming a building panel, as in claim 21, further comprising the step of:
placing a selected detail form contiguous to the surface of said panel mixture exposed at the top of said mold, while said panel mixture remains in said mold cavity, in a position to shape said panel mixture at said exposed top edge so that all four edges of the molded panel are formed into the desired shapes.
23. A method of forming a building panel, as in claim 21, further comprising the step of:
inserting bottom and side details in said mold cavity prior to filling said mold cavity with said panel mixture to shape said panel mixture at said bottom and side edges.
24. A method of forming a building panel, as in claim 21, further comprising the step of:
spraying said mold cavity with a mold release to facilitate the removal of the integral assembly of cured panel mixture and foam insert from said mold cavity.
25. A method of forming a building panel, as in claim 21, wherein the step of positioning and securing a foam insert in said mold cavity further comprises the step of:
inserting, on opposite sides of said foam insert positioned in said mold cavity, spacing fingers intermediate said foam insert and the mold cavity walls for keeping said foam insert centered in said mold cavity and preventing said foam insert from moving and warping as the mold cavity is filled with panel mixture.
26. A method of forming a building panel, as in claim 25, further comprises the step of:
withdrawing said spacing fingers from said mold cavity gradually as said panel mixture fills said mold cavity and bonds with said foam insert, allowing the partially set-up panel mixture to hold said foam insert in position.
27. A method of forming a building panel, as in claim 21, wherein the step of positioning and securing a foam insert in said mold cavity further comprises the step of:
providing hold-down members, mounted on an upper exposed edge of the foam insert, for holding said foam insert in position and prevent it from moving position while filling said mold cavity with panel mixture.
28. A method of forming a building panel, as in claim 27, further comprises the steps of:
removing said hold-down members from said foam insert as said panel mixture fills said mold cavity, sets up and bonds with said foam insert, allowing the panel mixture to hold said foam insert in position;
adding additional mixture to cover said foam insert; and,
inserting an edge detail at the top of the mold to form a channel in the edge of said panel.
29. A method of forming a building panel, as in claim 21, further comprises the step of:
mounting a vibrator on said mold for helping to spread uniformly said panel mixture in said mold cavity.
30. A method of forming a building panel, as in claim 21, further comprises the step of:
providing a vertical channel in said foam insert to allow rapid and uniform filling of said mold cavity.
31. A method of forming a building panel, as in claim 30, further comprises the step of:
cutting at least one vertical channel on at least one side of said foam insert to allow rapid and uniform filling of said mold cavity.
32. A method of forming a building panel, as in claim 21, wherein the step of providing a mold having a mold cavity, disposed vertically, defining the mold surface for forming the exposed finish surface of a molded wall panel, where the mold cavity bottom and side edge walls define three of the edge walls of the molded wall panel, further comprises the step of:
providing a mold having two separate, vertically disposed mold cavities having a shared common mold cavity wall for simultaneously producing two molded wall panels.
33. A method of forming a building panel, comprising the steps of:
providing a mold having a mold cavity, disposed vertically, that defines the mold surface for forming the exposed finish surface of a molded wall panel, where the mold cavity bottom and side edge walls define three of the edge walls of the molded wall panel;
positioning and securing a foam insert in said mold cavity;
mixing a liquids component including water;
mixing thoroughly about 14 percent by weight of said liquids component with about 86 percent by weight solids component consisting of cement, sand and strengthening fiber components to produce a homogeneous panel mixture;
filling said mold cavity with said panel mixture and leveling said panel mixture with the mold side edge walls;
effecting the setup and initial cure of said panel mixture in said mold and the bonding of said mixture to said foam insert; and,
removing the integral assembly of partially cured panel mixture and foam insert from said mold cavity.
34. A method as in claim 33, wherein said sand component in said solids component is selected from a group consisting of plaster wash sand, dolomite, perlite, silica, ground quartz and slack.
35. A method as in claim 33, wherein said sand component in said solids component is comprised of a mixture consisting of plaster wash sand and silica.
36. A method as in claim 35 wherein said plaster wash sand comprises about 10 to 50 percent of said sand component, and said silica comprises about 90 to 50 percent of said sand component, the percentages being expressed as weight percentages.
37. A method as in claim 35 wherein said plaster wash sand comprises about 10 to 90 percent of said sand component, and said silica comprises about 90 to 10 percent of said sand component, the percentages being expressed as weight percentages.
38. A method as in claim 33, wherein said strengthening fiber component in said solids component is selected from a group consisting of strands of glass fiber, polyprophelene, nylon, and carbon or graphite fiber.
39. A method as in claim 38 wherein said fiber strands are about to inch in size.
40. A method as in claim 33 wherein the step of mixing a liquids component including water further comprises the step of:
adding an acrylic polymer to control the curing time of said panel mixture.
41. A method as in claim 40 wherein said acrylic polymer is added to the liquids component in an amount of about 5 to 10 percent by weight of said liquid component.
42. A method as in claim 33 wherein the step of mixing a liquids component including water further comprises the step of:
adding a super plasticizer to control the flowability of said panel mixture.
43. A method as in claim 42 wherein said super plasticizer is added to the liquids component in an amount of about to 8 ounces per 94 pounds of cement in said solids component.
44. A method as in claim 33 wherein the step of mixing a liquids component including water further comprises the step of:
adding a concrete extender to control the curing of the panel mixture due to temperature.
45. A method as in claim 44 wherein said concrete extender is added to the liquids component in an amount of about to 2 ounces per 94 pounds of cement in said solids component.
46. A method as in claim 33 wherein the step of mixing a liquids component including water further comprises the step of:
adding an anti-foaming agent for controlling the creation of voids in said molded panel.
47. A method as in claim 46 wherein said anti-foaming agent is added to the liquids component in an amount of about to ounces per 94 pounds of cement in said solids component.
Description
    BACKGROUND OF THE INVENTION
  • [0001]
    1. Field of the Invention
  • [0002]
    The present invention relates in general to the building wall panel art, and more particularly pertains to the art of manufacturing a molded modular building wall panel formed from a fiber reinforced concrete and a method of vertically molding same.
  • [0003]
    2. Description of the Prior Art
  • [0004]
    A long felt need in the construction industry, and more particularly in the building wall panel field, is to find a durable, yet relatively inexpensive construction method and material that would allow the construction of attractive and durable homes in a quick and economic manner.
  • [0005]
    Although the thrust of this need has initially been to provide housing for low-income families or for first time home buyers, any such construction method and material could also be easily adapted for more expensive homes and multi-family housing units.
  • [0006]
    One such attempt to create such a relatively inexpensive construction method and material has resulted in the use of precast or molded glass fiber reinforced concrete (GFRC) building panels.
  • [0007]
    The development of lightweight precast construction panels has been gradual and not without many shortcomings. Initial attempts to manufacture such panels have met with many problems, for example, attempting to lower the weight of a concrete panel while maintaining its load bearing strength, various reinforcing designs and inserts have been tried, for example, insulating foam blocks were inserted into the panel during the molding process to be encased within the GFRC matrix. However, such foam inserts, while lessening the weight of the panel, posed new challenges in laminating or bonding the concrete to the foam insert and in producing a consistent and useful building panel.
  • [0008]
    While such foam inserts provided a tremendous benefit in lessening the weight of the panel and insulating the structure against heat and cold, great difficulties arose during the molding process in keeping the foam inserts from warping or shifting. Such warping or shifting of the foam inserts results in panels having side walls with irregular thickness, voids and reduced load bearing strength.
  • [0009]
    Accordingly, much work has been done in the casting of such panels, all of which includes using a horizontally disposed or oriented mold, open on top, to limit and control any warping or shifting of the foam inserts due to hydrostatic pressures that develop during the molding process. In this horizontal molding process one face of the panel is flat on one face of the mold. A layer, typically of an inch of Glass Fiber Reinforced Concrete (GFRC) is first poured onto the bottom face of the mold, then a foam insert, such as a panel of expanded polystyrene foam, is placed on top of the GFRC layer and some weight, such as sand bags are placed on the foam insert to hold it in place from hydrostatic pressures that arise subsequently when more GFRC is then poured into the mold around the sides and top of the foam insert.
  • [0010]
    In this horizontal molding method, the mold has no top face, so after removing the sand bags and pouring the GFRC on top of the foam insert, the exposed GFRC layer had to be manually smoothed, as it would become one of the finished panel faces. Various steps in this horizontal molding process are difficult and inefficient, including the need to hold the foam insert in position, produce GFRC panel walls of uniform thickness and sufficient smoothness. It is also difficult, with such methods, to achieve good bonding or lamination between the foam and the GFRC.
  • [0011]
    Another problem with current methods of construction using molded building panels is the methods by which these panels are interconnected in the construction process. Some known methods require the insertion of reinforcing bars with extending ends, which extending ends are then used as lashing points for holding the panels in place. However, these construction methods also require added cost, expertise in properly encasing such reinforcing bars and a greater expertise in the construction team workers installing the panels.
  • [0012]
    By way of example, the prior art of casting such GFRC building panels are found in such representative references as U.S. Pat. No. 3,885,008 to Martin; U.S. Pat. No. 3,965,635 to Renkert; U.S. Pat. No. 4,185,437 to Robinson; U.S. Pat. No. 4,232,494 to Bauch et al.; U.S. Pat. No. 4,453,359 to Robinson; U.S. Pat. No. 4,531,338 to Donatt; U.S. Pat. No. 4,542,613 to Leyte-Vidal; U.S. Pat. No. 4,691,490 to Leaver; and U.S. Pat. No. 6,182,416 B1 to Bracklin.
  • [0013]
    However, the known molding processes are time consuming, labor intensive, and operationally expensive and produce building panels that are not only expensive, but also hard to obtain leading to long construction delays in building the structures themselves. Likewise, current building panels require costly construction methods for connecting the panels into the desired structure.
  • [0014]
    The present invention provides a solution to these and other problems of the present art in molded building panels by providing a building panel that is light-weight, easily and quickly cast with a minimal amount of labor needed in its manufacture and that is easily interconnected during the construction process to produce a sturdy structure.
  • [0015]
    At least in these respects, the method of construction and composition of the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides a building panel and method primarily developed for the purpose of providing a light-weight molded building panel for use in constructing durable and economical housing or other structures in a time efficient manner.
  • [0016]
    In these regards, at least, the present invention substantially fulfills these needs of the present art in molded building panel construction and manufacture.
  • SUMMARY OF THE INVENTION
  • [0017]
    In view of the foregoing disadvantages inherent in the known types of building panels and methods of molding such panels now present in the art, the present invention provides an improved molded composite construction panel that is formed in a vertically oriented continuous molding procedure. The panel of the present invention has, in general, a lightweight cellular core of rigid foam material and a relatively thin skin of glass fiber reinforced concrete encasing the foam core.
  • [0018]
    The panel further has at least one integrally formed channel. The channel may be arcuate or multi-faceted in which case it would preferably be a semi-hexagon in cross-section, that is substantially coextensive with at least one side edge of the panel for construction connection purposes as will be better described below. However, the channel can be of any other cross-sectional shape such as a semi-circle, star, or X shape, just to indicate three acceptable shapes as examples, without limitation. In general, a goal for the choice of channel cross-sectional shape is that when adjacent panels are connected, the abutting channels meet to form a passageway big enough to hold at least one piece of reinforcing bar (rebar) while allowing concrete to be poured into the passageway to form an integral structure for reinforcing the connected panel construction in situ.
  • [0019]
    As such, the general purposes of the present invention, which will be described subsequently in greater detail, are to provide a new and improved molded building panel and method of making such panel as well as a method of connecting such panels in construction, which have all the advantages of the prior art and none of the disadvantages.
  • [0020]
    To attain this, the present invention in an embodiment for a method of forming a building panel, generally includes the steps of:
  • [0021]
    providing a mold having a mold cavity that is disposed vertically. (It should be noted for clarity, that although the mold cavity is disposed vertically, the panel being molded need not also be vertically oriented as to its final installation, i.e., the mold cavity being disposed vertically does not imply that the panel is actually molded in its normal vertical position with the top of the final panel at the top of the mold.) The mold cavity defines the mold surface for forming the exposed finish surface of a molded wall panel, where the mold cavity bottom and side edge walls define the various edge walls of the molded wall panel.
  • [0022]
    positioning and securing a foam insert in the mold cavity. The foam insert is inserted inside the panel to provide strength and rigidity to the finished panel while at the same time lessening the weight of the panel over a solid concrete panel and improving thermal insulation;
  • [0023]
    forming a slurry of concrete, sand, and glass fiber strands to produce a homogeneous panel mixture commonly referred to as a GFRC panel mixture;
  • [0024]
    positioning in the mold (optionally) one or more reinforcing bars in such positions as to be embedded within the GFRC in the final panel;
  • [0025]
    filling the mold cavity with the panel mixture and leveling the panel mixture with the mold side edge walls to fill out the form of the mold cavity;
  • [0026]
    effecting the cure of the panel mixture in the mold and the bonding of the panel mixture to the foam insert; and,
  • [0027]
    removing the integral assembly of cured panel mixture and foam insert from the mold cavity.
  • [0028]
    It should be noted that the strength and flexibility of the panels embodying the present invention can be used throughout a structure for both load supporting and non-load supporting walls, floors, headers and even roofs.
  • [0029]
    There has thus been defined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
  • [0030]
    In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
  • [0031]
    As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
  • [0032]
    It is therefore an object of the present invention to provide a new and improved molded building panel, construction and connection methods, which have all the advantages of the prior art molded building panels and none of the disadvantages.
  • [0033]
    It is another object of the present invention to provide a new and improved molded building panel, construction and connection methods, which may be easily and efficiently manufactured and assembled.
  • [0034]
    It is a further object of the present invention to provide a new and improved molded building panel, construction and connection methods, which produce a durable and reliable construction.
  • [0035]
    An even further object of the present invention is to provide a new and improved molded building panel, construction and connection methods, whose design, structure, and construction steps are simplified, while permitting a mastery and optimal control of the molding and interconnecting process for such precast building panels.
  • [0036]
    Still yet another object of the present invention is to provide a new and improved molded building panel, construction and connection methods, whose use and steps facilitate the construction process.
  • [0037]
    Lastly, it is an object of the present invention to provide a new and improved molded building panel, construction and connection methods, which are safe for home and commercial construction use.
  • [0038]
    These together with other objects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is an illustrated preferred embodiment of the invention.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0039]
    The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
  • [0040]
    [0040]FIG. 1 is a molded building panel that has been constructed in accordance with the principles of the present invention.
  • [0041]
    [0041]FIG. 2 is a cross-sectional view taken along the line 2-2 in the direction shown in FIG. 1;
  • [0042]
    [0042]FIG. 3 is a cross-sectional view taken along the line 3-3 in the direction shown in FIG. 1;
  • [0043]
    [0043]FIGS. 4A, 4B and 4C are cross-sectional views of various type of channels or details formed in the sides of a molded panel embodying the present invention;
  • [0044]
    [0044]FIGS. 5A, 5B, 5C, 5D and 5E are cross-sectional views of different panel joining constructions utilizing a molded panel embodying the present invention;
  • [0045]
    [0045]FIG. 6 is a side plan view of a mold useful for molding panels embodying the present invention;
  • [0046]
    [0046]FIG. 7 is a cross-sectional view taken along the line 7-7 in the direction shown in FIG. 6;
  • [0047]
    [0047]FIG. 8 is a cross-sectional view of a curved panel mold useful for molding panels embodying the present invention;
  • [0048]
    [0048]FIG. 9 is a side view of a mold useful for molding panels embodying the present invention having spacers and dividers inserted (shown in dotted outline) to form multiple smaller cavities for molding multiple small panels at the same time;
  • [0049]
    [0049]FIG. 10 is a cross-sectional view of a mold useful for molding panels embodying the present invention illustrating that the outer faces of the mold can be placed in multiple slots to form panels of multiple thicknesses;
  • [0050]
    [0050]FIG. 11 is a side view of a mold useful for molding panels embodying the present invention illustrating in dotted outline the use of spacing fingers to maintain the desired position of the foam core during the pouring process; and, FIG. 12 is a cross-sectional side view taken along line 11-11 of FIG. 11 in the direction shown, illustrating a single mold cavity with a foam core in place and spacing fingers on both sides of the foam core to maintain precise separation between the foam core and the mold faces.
  • [0051]
    Similar reference characters refer to similar parts throughout the several views of the drawings.
  • DESCRIPTION OF THE PREFERRED EMBODIMENT
  • [0052]
    With reference now in the drawings, and in particular in FIG. 1 thereof, a new and improved molded building panel and connection methods for such a panel, which embody the principles and concepts of the present invention and generally designated by the reference numeral 10 will be described. The construction of such a panel will be described afterwards below.
  • [0053]
    The new and improved molded building panel 10 embodying the present invention is comprised of a plurality of components that are integrated into a single unit. Such components in their broadest context include an internal foam insert 12 encased in a matrix 14 of preferably glass fiber reinforced concrete. Such components are individually configured and correlated with respect to each other so as to attain the desired construction or structural objective for which the panel is being manufactured, that is, the size and shape of the panel may be changed to suit the desired structural demands of the particular job and location of the specific panel.
  • [0054]
    More specifically, with reference being made to the Figures, the present invention includes a molded composite construction panel 10 that is formed in a vertically oriented continuous molding procedure described below. Note that the mold need not be precisely vertical, but may be tilted by some amount from the vertical. Panel 10 has a lightweight cellular core of rigid foam material 12 that is encased in a relatively thin skin of glass fiber reinforced concrete 14. Relatively thin skin of glass fiber reinforced concrete means, generally, an encasing layer having about {fraction (1/16)} to inch thickness.
  • [0055]
    Rigid foam material 12 preferably has chamfered or beveled edges 13 a and may also include a textured surface or additional chamfered channels 13 b on its faces to aid in bonding the foam material 12 to the glass fiber reinforced concrete 14 surrounding the foam material 12.
  • [0056]
    Panel 10 preferably has integrally formed multi-faceted channels 16 that are substantially coextensive with the side edges of panel 10 as shown in FIGS. 1 to 3. Channels 16 are best shaped to be semi-polygonal in cross-section, such as a semi-hexagon for joining two panels during construction, but may be other specific faceted shapes as well as shown in FIGS. 4A, 4B, and 4C. The shallower channel formed by a cross-sectional shape 22 as in FIG. 4A is useful for the panel sides, while the cross-sectional shapes 24, 26, shown in FIGS. 4B and 4C, respectively, are useful for the top and bottom sides of the panel respectively.
  • [0057]
    Testing has shown that while many cross-sectional shapes are useful, the greater the number of facets and planar intersections found in the cross-sectional aspect of the channels, the greater the strength when panels are joined.
  • [0058]
    Generally, as shown in FIGS. 5A and 5B, channels 16 are butted one to another. Steel reinforcing bars are placed in the channels and a concrete fill 30 is poured in to fill the channels. Once the concrete fill 30 is hardened, the joint forms a very strong construction, capable of bearing tremendous loads.
  • [0059]
    Wall ends and the sides of door and window openings can be made as shown in FIG. 5C where the otherwise open channel 16 has reinforcing bars 28 placed in it and a concrete fill 30 is molded to the desired open edge shape.
  • [0060]
    [0060]FIGS. 5D and 5E illustrate various cross-sections of panels and preferred uses for each in construction. FIG. 5D shows a panel 50 that is useful as a window/door header. On such window/door header type panels, note that the upper channel 52 at the top of the panel is preferably configured for the connecting and supporting beam material to be poured into. The foam insert 54 is shown with chamfered corners 56, and the rectangular bottom part 58 of the panel is formed with thick GFRC which typically would include one or more rebars 60 inside it to provide tensile strength.
  • [0061]
    The panel 62 shown in FIG. 5E, which is useful for the short wall section below a window, has no channel on its upper edge 64, but may optionally have one or more bolts 66 inserted in the GFRC 68 for use in fastening the window frame.
  • [0062]
    Electrical raceways, illustrated at reference numeral 18 in FIG. 1 may be embedded within panel 10 during the molding process with respective raceways in adjacent panels being adapted for interconnection upon securement of the panels to form an internal electrical raceway network so that an electrician will not have to mar or dig into a panel during installation of a structure's electrical wiring system. In addition, the panel is further preferably provided with recesses 20 that are in communication with an end of raceway passageways 18. Recesses are intended to be adapted for receiving an electrical junction box.
  • [0063]
    Likewise, water conduits can also be embedded within the panels during the molding procedure with the respective conduits being adapted for interconnection upon the joining of adjacent panels to form an internal water conduit network similar to that discussed above for electrical wiring.
  • [0064]
    Both the electrical and water conduits may be either embedded in the panels or open channels may be molded into the panels to receive the wiring or pipes which are then covered over with sheeting. It is preferred in many constructions to have these conduits molded into the panels to avoid having to run unsightly or even out of code wiring or plumbing outside of the walls of the completed buildings.
  • [0065]
    A method embodying the present invention that is useful for forming a building panel as described above, would include the following described steps.
  • [0066]
    Step 1: Providing first a mold 32 that has a mold cavity 34 that is disposed vertically. Such a vertically disposed mold 32 is shown in FIGS. 6 and 7. This vertical orientation is a departure from known prior art and is significant in allowing not only stronger panels to be cast quickly, but in allowing the molding process to be more efficient than horizontal molding techniques currently in use. The walls 36 of the mold cavity 34 define the mold surface for forming the exposed finish surface of the finished molded wall panel. Specifically, the mold cavity bottom 38 and side edge walls 40 define edge walls 44 of the molded wall panel 10. Note that the top of the panel need not be at the top of the mold; in general, the panel will be molded in whatever orientation is most convenient. For example, typical tall panels may be molded lying on their side, and window headers may be molded upside-down because they usually have rebar in their bottom edge, and it is easier to place the rebar at the top of the mold.
  • [0067]
    Another aspect of the present invention is that the molds may be varied to create panels of various thickness and shape. Specifically, the overall thickness of the panel is determined by how far each outside mold wall is from the middle wall when the mold cavities are placed side by side as described below. At the bottom, as shown in FIG. 10 and explained in greater detail below, the horizontal steel base piece into which the vertical sides are held, has slots at various distances from the middle wall, and the outer wall of the mold can be inserted into any of those slots, allowing panels to be made in several discrete thicknesses using the same molds. Of course, the edge details that form the shape of the panel edges must be customized for each thickness, but those are normally formed from sheet metal and are cheap to make and easy both to store and insert. The molds themselves are much bigger, heavier and more expensive, so it is a real benefit that one mold can be used to make panels having walls of different thicknesses. It should be noted that the slots for inserting the outer walls appearing in the horizontal steel base piece that are of a lesser thickness than the panel being molded, do not get filled with GFRC during the molding process because the metal edge details cover them during molding.
  • [0068]
    Step 2: Positioning and securing a foam insert 12 in mold cavity 34. It is essential that foam insert 12 be held both securely and accurately in mold cavity 34, especially during the pouring process described below which causes a great deal of hydrostatic pressure to develop in mold cavity 34. These pressures tend to distort or warp foam insert 12 and to cause it to “float” as the slurry described is poured in cavity 34. Warping and shifting of foam insert 14 can cause thin spots in the GFRC shell of the finished molded panel unless properly controlled during the pouring process as better explained below.
  • [0069]
    Step 3: Forming a slurry of concrete, sand, and glass fiber strands to produce a homogeneous panel mixture. The composition and selection of materials to form this slurry is critical, especially in light of the vertical orientation of the mold 32 which requires different compositions than that used for horizontal moldings.
  • [0070]
    In one preferred embodiment, the sand component is comprised of a mixture consisting of plaster wash sand and silica sand where the plaster wash sand comprises about 10 to 50 percent, and the silica portion comprises about 90 to 50 percent of the sand component, where the percentages are being expressed as weight percentages. These are rough guidelines and also includes where the plaster wash sand comprises about 10 to 90 percent, and the silica portion comprises about 90 to 10 percent of the sand component. Once again the percentages are being expressed as weight percentages.
  • [0071]
    The strengthening fiber component in the solids component is preferably selected from a group consisting of strands of glass fiber, polyprophelene, nylon, and carbon or graphite fiber. More specifically, the fiber strands are preferably selected to be about to inch in size. As is generally known in the art, the glass fibers should be alkali-resistant to avoid being damaged by the concrete. In general, the strengthening fibers may consist of any fibers with high tensile strength that can bond with the concrete without being chemically degraded over time.
  • [0072]
    While the exact formulation of the mixture is somewhat of an art due to variations in temperature, humidity, shape of the panel, etc., the above formulations are generally used. The following additions, however, may be made to achieve certain goals, such as adding an acrylic polymer to control the curing time of the panel mixture in an amount of about 5 to 10 percent by weight of the liquid component.
  • [0073]
    Likewise, a super plasticizer can be added to control the flowability of the panel mixture during the pouring process into the vertical mold cavity. Generally, a preferred range for adding the super plasticizer is in an amount of about to 8 ounces per 94 pounds of cement in the solids component.
  • [0074]
    Also a concrete extender may be added to the liquids component to control the setup of the panel mixture due to temperature in an amount of about to 2 ounces per 94 pounds of cement in the solids component.
  • [0075]
    It has also been found that adding an anti-foaming agent to the liquids component in an amount of about to ounces per 94 pounds of cement in the solids component controls and prevents the creation of voids in the molded panel.
  • [0076]
    Step 4: Filling mold cavity 34 with the prepared panel mixture and leveling the panel mixture with the mold side edge walls to fill all voids in the mold cavity 34.
  • [0077]
    Step 5: Effecting the cure of the poured panel mixture in mold 32 and the bonding of the mixture to foam insert 12; and,
  • [0078]
    Step 6: Removing the integral assembly of cured panel mixture and foam insert 12 from mold cavity 34.
  • [0079]
    While the above 6 steps may be sufficient to embody the present invention, it is preferred to add additional steps that further embody the present invention as the following:
  • [0080]
    Placing selected details on the top, bottom and sides of the mold cavity to shape the panel mixture at the side edges of the molded wall panel to form desired channels in the panel edges. This is best illustrated by the bottom detail 46 shown in FIG. 7 placed in the bottom 38 of the mold cavity, and the formed channels that appear in the sides of the molded panel in the other FIGS. These channels are useful for creating the bonding joint discussed elsewhere above for joining two adjacent panels, and for forming the horizontal concrete beam across the tops of panels during construction of the building.
  • [0081]
    Also, it is preferred that a step be added of spraying the mold cavity with a mold release to facilitate the removal of the integral assembly of cured panel mixture and foam insert from the mold cavity once it has cured.
  • [0082]
    As was mentioned above, it is necessary that the foam insert be held in the mold cavity in a known and secure position during the pouring process as the hydrostatic pressures created during the pouring process will try to float and warp the foam insert. One preferred method of securing the foam insert in the mold cavity is embodied in the following step which is illustrated in FIGS. 11 and 12:
  • [0083]
    Inserting, on opposite sides of the foam insert when it is positioned in the mold cavity, spacing fingers that are intermediate the sides of the foam insert and the mold cavity walls for keeping the foam insert centered in the mold cavity and preventing the foam insert from moving and warping as the mold cavity is filled with panel mixture.
  • [0084]
    It is further preferred, during the pouring process, as the mixture rises to fill the mold cavity, to perform a step of:
  • [0085]
    Withdrawing the spacing fingers gradually from the mold cavity as the panel mixture fills the mold cavity, and bonds with the foam insert. The panel mixture sets up enough to hold the foam insert in position as the spacing fingers are withdrawn.
  • [0086]
    Also, to prevent the foam insert from “floating” during the pouring process, it is preferred that a step be added to the process of:
  • [0087]
    Providing hold-down members, mounted on the mold, held down against an upper exposed edge of the foam insert, to hold the foam insert in position and prevent it from floating upwards while filling the mold cavity with the panel mixture.
  • [0088]
    As with the spacing fingers, the hold-down members should be removed from contact with the foam insert as the panel mixture fills the mold cavity and begins to flow over the top of the foam core.
  • [0089]
    It is further preferred that a vibrator 48 be mounted on the mold 32, as illustrated in FIG. 6, for helping to spread uniformly the panel mixture in the mold cavity 34 by enhancing its flowability. A low frequency of vibration is preferred to agitate the panel mixture to eliminate voids in the poured panel.
  • [0090]
    Another step to eliminate or at least lessen the possibility of voids forming in the panel is to add a step of:
  • [0091]
    providing a vertical channel in the foam insert to allow rapid and uniform filling of the mold cavity. Actually a number of channels to help the uniform spread of the panel mixture as it is poured into the mold cavity can be cut into the foam insert. Cutting at least one vertical channel in opposite sides of the foam insert (as illustrated by the channels 76 in FIG. 8) to allow rapid and uniform filling of the mold cavity is one such example of providing such channels.
  • [0092]
    It has also been found that from both an economic and a mechanical standpoint, it is preferred that the vertically oriented mold be provided with two, adjacent mold cavities sharing a common wall as shown in FIGS. 6 and 7. This configuration not only makes a more efficient use of floor space by providing a smaller manufacturing “footprint” for the mold while simultaneously making two panels, but the common wall vertical configuration also lessens the large hydrostatic forces applied on the mold cavity walls by allowing at the least the forces along the common wall to cancel one another by acting in generally opposite directions. Of course for this to be effective, both mold cavities must be filled at the same rate to allow equal, but opposing forces to develop against the common wall in each mold cavity.
  • [0093]
    While the panels described so far have a flat or planar configuration, it is also within the scope of the present invention to produce panels of varying configurations and shapes. For example, FIG. 8 illustrates a curved mold 70, as viewed from above, for use in forming curved panels as for a turret structure. Unique molds would be made for each required radius of curvature. The figure shows the edge details 72 in place and the pre-curved foam core 74 inside the mold 70. Note that this foam core 74 shows the V-shaped channels 76 that run vertically to facilitate pouring the GFRC mixture, letting it flow freely to the bottom of the mold. The curved black bar 78 is the bar that holds the foam down during pouring of the GFRC, and the black cross pieces 80 are the metal pieces that hold bar 78 in place during the pouring process.
  • [0094]
    Likewise, as shown in FIG. 9, the mold cavity 82 used to produce such panels may have internal spacers/dividers 84 inserted to form multiple small panels at the same time in one typical mold cavity 82. Window and door headers are good examples of small panels that can be molded this way. Such spacers/dividers make the molds more versatile, so most molds can be made in a standard overall size and shape, yet can be used for making any of the smaller sized panels with only a minimum modification.
  • [0095]
    Also for greater versatility, FIG. 10 illustrates the lower part of a double mold 86, showing that the bottom plate 88 can have multiple slots 90 for receiving the bottom edges 92 of the outer mold faces 94. This configuration allows one mold to be used to create panels of several different thicknesses. The bottom edge detail insert 96 is shown, making it clear that it covers one of the slots 98, preventing it from filling with GFRC during the pouring process. This makes each mold unit more versatile, letting each one be used for multiple panel thicknesses, e.g., 4.5″, 6.5″, and 8.5″. Note that it is also useful that the side walls 94 can be completely removed, facilitating removal of the molded panel once the GFRC has cured. It would also be possible to hinge the outer faces at the bottom, so each face could be rotated outward on its hinges. This would be an alternate means of facilitating the removal of completed panels, but would not lend itself to different thicknesses of panels. The most preferred embodiment would utilize the slots.
  • [0096]
    [0096]FIGS. 11 and 12 show the spacer “fingers” 100 used to hold the foam core 102 at precisely the right separation from the mold faces 104. The number of fingers and the width and thickness of each can obviously be varied in many ways.
  • [0097]
    These spacing fingers are gradually raised as the GFRC gradually fills the mold cavity, so that the fingers are usually kept just above the top surface of the GFRC mixture. The fingers are totally removed when the GFRC reaches the top of the foam. At that point, the top hold-down bar can also be removed, and then the last bit of GFRC can be added and the top edge detail can be pressed down into the GFRC at the top of the mold to form the desired channel or edge detail of the panel.
  • [0098]
    It is also possible to connect the fingers at their top ends so that two or more of them can be manipulated as one unit. Preferably, if the fingers are to be joined for manipulation as a unit, the fingers should be placed in pairs, with each one attached to the one facing it on the other side of the foam, and a simple block connects them. In principle, all the fingers could be connected using a beam across the top of the mold so that they could all be lifted at once.
  • [0099]
    Finally, the foam core must be kept at the desired distance above the bottom detail to allow the right thickness of GFRC at the molded bottom edge of the panel. This is important as the foam core will tend to float up as the GFRC is poured into the mold cavity, so it may be enough to place the top plate at the right height, so the foam core will be about ″ above the bottom detail when the core is in contact with the top plate. However, it is preferred to insert some very small spacers in the foam core at the edge that will be on the bottom edge of the mold. These can be little nail-like metal rods with a shoulder so they stick out about ″ from the foam core surface into which they are placed. With a few of these in the foam core, they hold the foam core in the desired position vertically from the start of the molding process. These spacers need not resist much force, since the GFRC tries to float the foam core. So the main structure for vertical placement of the foam core in the mold is the top plate or bar which is precisely positioned and only removed after the GFRC has totally enclosed the foam core and has set sufficiently to hold the foam core in place.
  • [0100]
    Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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Classifications
U.S. Classification52/782.1, 52/309.12, 52/309.1, 52/309.4, 52/309.17, 52/784.15
International ClassificationC04B14/06, E04C2/288, B28B23/00
Cooperative ClassificationB28B23/0056, E04C2/2885, C04B14/06, B28B23/0068
European ClassificationB28B23/00V, C04B14/06, B28B23/00T, E04C2/288B
Legal Events
DateCodeEventDescription
Mar 18, 2002ASAssignment
Owner name: HOUSING TECHNOLOGY, INC., A CALIFORNIA CORPORATION
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STEPHENS, RODNEY O.;STOCKING, JR., HARREL DALE;REEL/FRAME:012731/0219;SIGNING DATES FROM 20011012 TO 20011014