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CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 10/327,723, filed Dec. 23, 2002, which claims the benefit of U.S. Provisional Application Serial No. 60/344,835, filed Dec. 21, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates generally to supports used for creating cured pre-cast panels and related structures, and more specifically to the configuration of extensions used to create recesses at panel edges and apertures that are used to define windows, doorways and related openings in the panel.  
           [0003]    Many residential and commercial construction methods involve the use pre-cast structures. Pre-cast panels, for example, are integral to the tilt-up construction process. In the tilt-up approach, concrete forms are arranged on a flat casting surface in the shape and dimension of the desired tilt-up panel, then filled with concrete. When the concrete cures, the panel and the form are separated and the panel is tilted up into a preferred, typically vertical, orientation, where it can be joined to structural frames or other panels. The present inventors have recognized a need for improvements in pre-cast panel forming systems and in various components of the panel forming systems. The improvements introduced by the present invention have applicability in the tilt-up construction process and in other pre-cast construction processes.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    This need is met by the present invention wherein improvements in pre-cast panel forming systems and in various components of the panel forming systems are introduced. In accordance with one aspect of the present invention, a panel-forming system is disclosed. The panel-forming system includes a plurality of bulkheads and at least one aperture extension. The bulkheads and aperture extensions are placed on a panel-forming surface. In the present context, the bulkheads and aperture extensions are placed “on” a panel-forming surface, which is meant to be broadly construed, thus encompassing situations where both direct contact between the panel-forming surface (which may be, for example, a smooth floor) and the bulkheads and aperture extensions, as well as indirect support (where, for example, a release liner may be placed over the panel-forming surface prior to arrangement of the bulkheads or aperture extensions) are contemplated. The bulkheads include a first group and a second group, where the first group is arranged into the shape of the panel to be formed, while the second group is disposed substantially within a shape formed by the first group. In the present context, the term “substantially” is utilized to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. As such, it refers to an arrangement of elements or features that, while in theory would be expected to exhibit exact correspondence or behavior, may, in practice embody something slightly less than exact. The term also represents the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.  
           [0005]    Upon formation of a panel (such as by pouring an uncured panel-forming material, for example, concrete into the dimensions bounded by the two bulkhead groups), the space that is substantially surrounded by the second group defines an aperture in the panel. The aperture extension includes a bulkhead-engaging portion configured to contact the bulkhead; and a recess portion formed separately from the bulkhead-engaging portion such that upon formation of the panel, a pattern becomes defined therein by surfaces on the aperture extension that are configured to face the panel. The bulkhead-engaging portion includes a first chamfer disposed adjacent at least one of the plurality of bulkheads and a second chamfer laterally spaced relative to the first chamfer. The recess portion is configured to support at least a portion of the bulkhead-engaging portion. Thus, in contrast to conventional panel-forming systems that merely include a chamfer designed to create a bevelled recess near a panel edge that is defined by an aspect ratio of unity or thereabouts, the device of the present invention contemplates myriad recess transition possibilities, including long, gradual recesses and multifaceted recesses, which taken alone or together provide the panel designer with numerous functional and aesthetic options.  
           [0006]    Optionally, the first and second chamfers on the bulkhead-engaging portion are separated by a region substantially non-coplanar with either of the chamfers such that a surface in the panel formed by the bulkhead-engaging portion is multifaceted. In one form, the surface disposed between the first and second chamfers is a plateau. In a more particular form, the first and second chamfers define a succession of chamfers descending away from the bulkhead. In such a descending pattern, the thickness of the castable material in the finished panel increases as the lateral distance away from the bulkhead increases. In one configuration, the bulkhead-engaging portion further comprises a stiffening rib configured to engage the recess portion, thereby strengthening the aperture extension. In another option, the recess portion extends laterally away from the bulkhead farther than does the bulkhead-engaging portion. In addition, the recess portion may extend a substantial entirety of the distance between two bulkheads, or, in another option, may extend less than the substantial entirety of the distance between two of the plurality of bulkheads. In this way, a distal end defined in the recess portion is situated away from the bulkhead, while a proximal end is situated adjacent the bulkhead. In the configuration where the recess portion does not extend across the substantial entirety of the distance between two bulkheads, an extension cap or an intermediate, each configured to engage the distal end of the recess portion, can be included. In another option, at least one stiffening rib disposed along the recess portion in a manner similar to that of the bulkhead-engaging portion. This recess portion stiffening rib may be configured to frictionally engage a base clip. Such an arrangement could be used to assist in securely mounting the recess portion to the panel-forming surface. In one configuration, the frictional engagement between the base clip and the stiffening rib is made up of complementary prismatic members disposed on coupling surfaces of the clip and the rib. Another option is that one or both of the chamfers may comprise a seal.  
           [0007]    In yet another option, the aperture is surrounded in its entirety by the second group such that a window is defined therebetween. In an alternate configuration of this option, the aperture is surrounded by both the first and second groups such that a door is defined therebetween. In either case, the second group is configured to define a plurality of apertures in the panel. More particularly, the plurality of apertures in the panel are substantially aligned along at least one edge with one another.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0008]    The following detailed description of specific embodiments of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:  
         [0009]    [0009]FIG. 1A is an elevation view of an embodiment of the aperture extension of the present invention engaging a bulkhead;  
         [0010]    [0010]FIG. 1B is an elevation view of an alternate embodiment of the aperture extension of FIG. 1A;  
         [0011]    [0011]FIG. 1C is an elevation view of an alternate embodiment of the aperture extension of FIG. 1B;  
         [0012]    [0012]FIG. 2A is a partial view of the aperture extension of FIG. 1A, including an extension cap;  
         [0013]    [0013]FIG. 2B is a variation of the extension cap of FIG. 2A, showing breakaway portions along one or more notches;  
         [0014]    [0014]FIG. 2C is a variation of the connection between an aperture extension and an extension cap;  
         [0015]    [0015]FIG. 3A shows an intermediate;  
         [0016]    [0016]FIG. 3B shows an alternate embodiment of the intermediate;  
         [0017]    [0017]FIG. 3C shows yet an alternate embodiment of the intermediate;  
         [0018]    [0018]FIG. 4 shows the integration of the intermediate of FIG. 3B into an aperture extension;  
         [0019]    [0019]FIG. 5A shows an alternate embodiment of the aperture extension of FIG. 1A with an extension cap coupled to it, both connected by a base clip;  
         [0020]    [0020]FIG. 5B shows an alternate embodiment of the intermediates of FIGS.  4 A- 4 C;  
         [0021]    [0021]FIG. 6 shows a perspective view of a panel-forming system according to the present invention;  
         [0022]    [0022]FIG. 7A shows an alternate embodiment of the aperture extension of FIG. 1A;  
         [0023]    [0023]FIG. 7B shows a variation of the aperture extension of FIG. 7A; and  
         [0024]    [0024]FIG. 8 shows a perspective view of an alternate panel-forming system according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0025]    Referring first to FIGS. 1A, 1B and  6 , a panel-forming system  10  is placed on top of a panel-forming surface  5 , the latter of which is typically a smooth, generally planar surface. The panel-forming system  10  includes a plurality of bulkheads  20  (hereinafter first group bulkheads) that define the outer dimensions of the panel to be formed (not shown), a plurality of connectors  30  that can be used to secure the various first group bulkheads  20  together, and an additional plurality of bulkheads  40  (hereinafter second group bulkheads) that define the outer dimensions of one or more apertures  15  formed in the panel.  
         [0026]    In the formation of pre-cast (or tilt-up) panels, it is advantageous to form aperture shapes into the panel prior to forming and subsequent curing of the panel-forming material (such as concrete). These apertures can be entirely enclosed within the peripheral walls of the panel (forming openings for windows or the like), or they can be formed such that one or more dimensions coincide with one or more of the peripheral walls, thus forming a door-like opening. In the former case, aperture  15  is defined entirely by the second group bulkheads  40 , while in the latter by a combination of the second group bulkheads  40  (for internally-projecting portions of the aperture) and the first group bulkheads  20  for portions of the aperture that coincide with the panel periphery. In certain circumstances, it would be advantageous to provide extra definition around the periphery of aperture  15  such that the transition from aperture to panel is not so abrupt, thus providing enhanced aesthetics, as well as added resistance to cured material chipping and related breakage. In the present invention, aperture extensions  50  are employed during the panel-forming process to facilitate the formation of gradual, patterned aperture transition zones. The aperture extension  50  is defined by a relatively low aspect ratio, such that the lateral dimension L is larger than the height H. Representative lengths of the lateral dimension L range from eight to twenty inches, although the present invention is not limited to such lengths. The aperture extensions  50  may be made from numerous low-cost materials, including plastic. Moreover, the shapes defining the bulkhead-engaging portion and the recess portion can be made from low-cost manufacturing methods, such as extrusion. By using inexpensive, easy to work with materials, long sections of the aperture extensions  50  may be cut into desired length strips that can be easily assembled on the job site. Variations on aperture extension  50  are shown with particularity in FIGS. 1A and 1B, both including a bulkhead-engaging portion  52  to connect to bulkheads from the second group bulkheads  40 . The bulkhead-engaging portion  52  is configured as a generally U-shaped cup into which the lower edge of the bulkhead can rest. The aperture extension  50  also includes a recess portion  54  extending laterally from the bulkhead-engaging portion  52 . The recess portion  54  includes a panel-facing surface  54 A and a surface  54 B opposite the panel, where the shape of the former defines a pattern that gets formed into the panel when the panel-forming material is poured into the mold and subsequently cured. The recess portion  54  also includes chamfers  54 C at the proximal and distal ends, such chamfers used to help define the shape of the pattern formed into the panel. As shown with particularity in FIG. 1B, a seal  54 G is disposed at the terminus of the chamfer  54 C. The surface  54 B opposite the panel faces the panel-forming surface, and along with the rest of the space defined underneath aperture extension  50 , is configured to be generally free of panel-forming material. The seal  54 G forms a knife-edge that splays under the load of panel-forming material, thus inhibiting leakage of panel-forming material into the space formed under the aperture extension  50 . Stiffening ribs  54 D act as load-bearing structure to minimized deformation of aperture extension  50  under the weight of the panel-forming material. A series of prismatic engagement members  54 E are formed in the walls of ribs  54 D such that the ribs can frictionally engage complementary surfaces on a base clip  56 . The base clip  56  may be formed integral with or separate from the recess portion  54 , and can be secured to the panel-forming surface  5  by conventional adhesive or attachment means, including nails, screws or the like.  
         [0027]    Referring with particularity to FIG. 1B, the bulkhead-engaging portion  52  and the recess portion  54  are formed from separate, discrete members, in contrast to the one-piece (unitary) construction of FIG. 1A. In this configuration, the base clip  56  is also separate such that the aperture extension is formed by arranging the three components to fit together. Base clip  56  is shown with frictional engaging members  56 A that engage prismatic engagement members  54 E of the ribs  54 D of recess portion  54 . In this configuration, the bulkhead-engaging portion  52  has a chamfer  52 C at one end such that a portion of the pattern in the panel is formed by the bulkhead-engaging portion  52 . Seals  52 A and  52 B form a knife-edge similar to that of aforementioned seal  54 G to reduce leakage at the boundary formed between the aperture extension  50  and the bulkhead  40 .  
         [0028]    Referring with particularity to FIG. 1C, as with the embodiment shown in FIG. 1B, the bulkhead-engaging portion  52  and the recess portion  54  are formed from separate, discrete members; however, in contrast to the embodiment in FIG. 1B, the bulkhead-engaging portion  52  includes a plurality of chamfers, including first chamfer  52 C 1  adjacent the end nearest the bulkhead  40  and a second chamfer  52 C 2  adjacent the end nearest the recess portion  54 . These chamfers, spaced by an intermediate plateau  52 F, create a double recess profile in the panel (not shown) being formed. Moreover, the first and second chamfers  52 C 1 ,  52 C 2  together define a succession of chamfers descending away from bulkhead  40  such that the material (for example, concrete) making up the finished panel is thicker at a lateral position farther away from the bulkhead. It will be appreciated by those skilled in the art that the present invention merely shows two chamfers for convenience, and that it is within the scope of the present invention to incorporate additional chamfers (and plateaus) into the bulkhead-engaging portion  52 . The remote edges  52 A,  52 B of each of chamfers  52 C 1  and  52 C 2  respectively can be configured to be generally planar (as shown) or as seals, the latter shown representatively in FIG. 1B. Rib  52 D extends downwardly from bulkhead-engaging portion  52  to engage a surface below, such as panel-facing surface  54 A of recess portion  54 , in order to provide additional stiffness to bulkhead-engaging portion  52 . In addition, recess portion  54  is shown in partial, cutaway view. As such, it can terminate in a distal end similar to that of the recess portions shown in the remaining figures, including extending substantially the entire distance between bulkheads  40 , in which case an additional recess is formed in the part of the panel that extends between adjacent apertures, the thickness of such recess equal to the vertical distance from the panel-forming surface  5  to the panel-facing surface  54 A. As before, base clip  56  (only a portion of which is shown) with frictional engaging members  56 A can engage prismatic engagement members  54 E of the recess portion ribs  54 D to secure recess portion  54  to the panel-forming surface  5 .  
         [0029]    Referring with particularity to FIG. 6, a panel-forming system  10  is configured for a two-aperture  15  panel. Aperture extensions  50  are placed around all four walls that define each aperture  15 , thus forming a transition zone between the aperture  15  and the panel, where one corner is shown exposed to better depict the relationship between the bulkhead  40 , bulkhead-engaging portion  52 , recess portion  54  and base clip  56 . The dimensions of the aperture extensions  50  are shown to more clearly present the details herein, and not shown to scale, as for a typical bulkhead  40 , which may be four, eight, ten or twelve inches in height when placed edgewise on the panel-forming surface  5 , the height of the aperture extension may be on the order of two inches or less. It will, however, be appreciated by those skilled in the art that the representative dimensions discussed herein are not to be construed as limiting, as other sizes are within the scope of the present invention.  
         [0030]    Referring next to FIGS. 2A through 2C,  3 A through  3 C,  4 ,  5 A and  5 B, additional ways to extend the lateral dimension of the aperture extension  50  are disclosed. From the distal end of aperture extension  50 , an extension cap  58  is added. The extension cap  58  includes an upper surface  58 A, a chamfer  58 C with seal  58 B, stiffening ribs  58 D and (as shown with particularity on the configuration depicted in FIG. 2A) an integral base clip  56  with frictional engaging members  56 A. The configuration shown in FIG. 2A allows the distal end of the aperture extension  50  to lock with extension cap  58  through the base clip  56 . The configuration shown in FIG. 2B achieves the same, but further includes notches  60  such that a sacrificial region  58 F is defined between them. In this way, the full extension made possible by the extension cap  58  can be exploited, or the extension cap  58  can be broken away at the notches  60  such that once the sacrificial region  58 F is removed, the now-free end region  58 H can be moved adjacent proximal region  58 J and attached to another base clip (not shown). It will be appreciated that the wall thickness of the aperture extension  50  and extension cap  58  are shown exaggerated for clarity, but that the actual dimensions are relatively thin, subject to minimum structural requirements, to keep weight and raw material cost low. Thus, no appreciable gaps are formed between the lower surface of the ribs  58 D and the panel-forming surface (not presently shown), thus substantially preserving the desired panel shape along panel-facing surface  54 A and upper surface  58 A. Referring with particularity to FIG. 2C, a variation on the pattern formed in the panel by the aperture extension  50  is shown, where additional facets on the surface of recess portion  54  are included. An extension cap  58  is also included, where the interlocking connection between it and the aperture extension  50  is defined by complementary surfaces that are slidably engageable with one another along the longitudinal axis of the aperture extension  50 , rather than through the toothed prismatic members previously shown. Referring with particularity to FIGS. 3A through 3C, intermediates  62  are shown. These devices are capable of fitting in between the aperture extension  50  and an extension cap  58 , or can, if equipped with a chamfer  62 D (as shown in FIG. 3B), act as a surrogate for the extension cap  58 . Moreover, in situations where multiple apertures are formed into a single panel (such as that shown in FIG. 6), the intermediates  62  can act to bridge aperture extensions  50  or extension caps  58 , thereby forming contiguous aperture extensions. As with the aperture extension  50  and the extension cap  58 , the intermediate can include a base clip  56 , either as a separate member (as shown in FIGS. 3A through 3C), or as an integral (unitary) part, as shown with particularity in FIG. 4. In the latter case, a notch  60  functions in a manner similar to that of the previous notches, allowing the clip to be broken away if not needed. In situations where a further extension is desired from the intermediate, the base clip  56  is left in place to allow an additional member to be attached thereto. The base clip  56  disposed at the distal end of recess portion  54  of aperture extension  50  is also configured to allow easy removal (if desired). As shown in FIG. 4, other pattern configurations along the recess portion  54  are possible. FIGS. 5A and 5B show how both the extension cap  58  and the intermediates  62  can be combined with the aperture extension  50 . The intermediate in FIG. 5B shows, in a variation of the configurations of FIGS. 3A through 3C, an integrally-formed base clip  56  that does not have a breakaway feature built in. This can be used in situations where a robust intermediate is required.  
         [0031]    Referring next to FIGS. 7A and 7B, two variations on a multifaceted recess corner sealing device  80  are shown, where multifaceted recess corner sealing device  80  acts as a specific complement to aperture extension  50 . The multifaceted recess corner sealing device  80 , rather than emphasizing the low aspect ratio of the aperture extension  50 , projects more in the heightwise dimension. The bulkhead-facing side of multifaceted recess corner sealing device  80  is defined by a substantially upstanding face  80 A that forms a solid, generally planar surface. Individual faceted surfaces  80 B,  80 C,  80 D and  80 E are used to define the pattern formed in the panel upon the pouring and curing of the panel-forming material. Referring with particularity to FIG. 7A, the portion containing the various faceted surfaces can be removed along notches  60 . As with the earlier drawings, the dimensions of the multifaceted recess corner sealing device  80  are not necessarily to scale, and while capable of occupying the substantial entirety of the height of the bulkhead  40 , are typically relatively short in comparison. In the present figures, the bulkhead  40  is formed from a manufactured part (such as extruded plastic) that can include dimensions tailored to fit in addition to having a bulkhead-engaging portion  82 . It will be appreciated by those skilled in the art that the bulkhead  40  can be either a conventional form (such as a piece of lumber) or the aforementioned manufactured part. FIG. 7B highlights the inclusion of an edge seal along the longitudinal dimension of the multifaceted recess corner sealing device  80 . This seal, which can be made from a relatively soft, yet resilient, material, helps to prevent leakage of panel-forming material between the bulkhead  40  and the substantially upstanding face  80 A.  
         [0032]    Referring with particularity to FIG. 8, the use of the multifaceted recess corner sealing devices  80  in conjunction with the aperture extensions  50  are shown. Absent the presence of the substantially upstanding face  80 A from the multifaceted recess corner sealing device  80 , the ends of the aperture extensions  50  would be left exposed, thereby allowing uncured panel-forming material to seep in between the aperture extensions  50  and the panel-forming surface  5 . The multifaceted recess corner sealing devices  80 , which are shown extending along the entire lengthwise dimension of the panel-forming system  10 , act to close of the exposed end of the aperture extensions  50  that extend the width of the aperture  15 . As previously mentioned, the multifaceted recess corner sealing devices  80  need not extend all the way to the bulkheads  20  that define the ends of the panel-forming system  10 . In such a configuration, end caps  82  could be fitted onto the ends of the multifaceted recess corner sealing devices  80  to inhibit the flow of panel-forming material into the device cavities. The figure also shows in the gap between the two aperture extensions  50  disposed between the two apertures  15  where one of the intermediates  62  (specifically, an extended version of the variant shown in FIG. 3A) could fit to form a bridge between the two apertures  15 . By having the heightwise dimension of the multifaceted recess corner sealing device  80  be at least as tall as the highest exposed portion of the aperture extension  50 , the present system reduces the likelihood that panel-forming material will leak underneath the aperture extension  50 . As previously mentioned, the relative height of the aperture extension and the multifaceted recess corner sealing device  80  are shown somewhat enlarged for clarity.  
         [0033]    Having described the invention in detail and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the present invention is not necessarily limited to these preferred aspects of the invention.

Summary:
A panel-forming system including a plurality of bulkheads and one or more extensions. A first group of the bulkheads are used to define the overall dimensions and shape of the panel, while a second group are used to define at least one aperture formed into the panel. The aperture extensions are configured to allow various-shaped recesses to be formed in the panels adjacent the apertures, and are made up of a bulkhead-engaging portion and a separate recess portion that extends from and cooperates with the bulkhead-engaging portion. The surfaces of each bulkhead-engaging portion include a plurality of chamfers to create complementary surfaces in the panel being formed. In accordance with 37 CFR 1.72(b), the purpose of this abstract is to enable the United States Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract will not be used for interpreting the scope of the claims