Decorative elements for subceilings
This invention relates to subceilings of the type that utilizes square or rectangular panels supported on a suspended framework of interconnected inverted T-bar rails arranged in a series of geometric grid-like patterns, e.g., square, rectangular, etc. More particularly, this invention relates to decorative elements for covering the bottom surfaces of the T-bar rails while the panels rest on and are supported on the top surfaces of the T-bar rails. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Subceilings formed from square or rectangular panels resting on the top surfaces of horizontally disposed flanges of inverted T-bar rails are well known. Typically, a framework of rails is formed with parallel main runners, suspended from the ceiling above, intersecting with cross rails to provide a grid pattern, usually as 2 feet×2 feet squares or 2 feet×4 feet rectangles, to accommodate similarly-sized subceiling panels. In its basic functional form, the subceilings would have the bottom surfaces of the rail flanges exposed as flat boundary strips between the edge supported panels. 
     For what has become the conventionally styled and dimensionally standardized version of the inverted T-bar rail, the industry has developed tight-fitting capping elements. By cutting and removing a portion of the panel along its length- and width-extending bottom edges to accommodate the thickness of the capped T-bar rails, a substantially smooth flat bottom surface of the subceiling may be defined. 
     It has been an objective to provide the option of various architecturally-satisfying decorative effects in suspended ceilings that have exposed flat T-bar flanges in addition to the mere capping discussed in the previous paragraph. It has also been an objective to provide such decorative effects with elements that are designed to be easily added in place or easily removed and replaced to satisfy the customer&#39;s &#34;addiction&#34; to his or her &#34;remodeling habit&#34;. 
     2. Description of the Prior Art 
     In U.S. Pat. No. 4,848,054, the patentee has provided a hollow beam that is readily attachable to the conventional T-bar support from below without requiring additional fastening hardware such as clips or screws. 
     It is a similar object of the present invention to provide beams for capping the inverted T-bar support rails used in conventional support systems for subceilings that are readily attachable and removable from below without using any additional fastening hardware. 
     It is a further object of the present invention to provide a beam that is, once in place, constrained from undesired movement such as skewing or riding upwardly on the rail flanges. 
     It is a still further object to provide a decorative beam that is simpler and less expensive than the hollow beams of the prior art and displays a substantially greater amount of versatility in design than the hollow beams or the capping elements of the prior art. 
     SUMMARY OF THE INVENTION 
     The objects of this invention are accomplished by a decorative capping beam for covering the inverted tee-bar (T-bar) panel support rail comprising: 
     a flat portion having an upper surface and a bottom surface, and a width defined by two longitudinal edges; 
     a first return flange disposed along one upper edge of the flat portion integral therewith and extending inwardly; 
     a second return flange disposed along a second upper edge of the flat portion integral therewith and extending inwardly; 
     each of said return flanges having a downwardly-facing surface and an inwardly-facing edge; 
     said return flanges ! adapted to hold the upper surface of said flat portion substantially flush against the longitudinally extending T-bar rails of the runner member; 
     a plurality of elements integral with and extending downwardly from said bottom surface of said flat portion and longitudinally along the length of said bottom surface of said flat portion, said elements being disconnected from each other, wherein the visual appearance of said elements provide the decorative effect. 
     In simple terms, the invention is the combination of a tee-shaped ceiling support grid to which three-dimensional decorative elements or beams are applied. The beams snap on the face of the grid via resilient hooked arms. The arms are connected by a web which lies against the face of the tee- shaped grid when engaged. Perpendicular to this face is a plurality of vertical members which are arranged to provide the decorative portion of the web. The snap-on feature, therefore, is not necessarily integral with the decorative feature. Thus, the decorative feature is not restricted in size or shape by the attachment mechanism or by the tee grid. 
     In addition, the beam can be snapped onto the grid with ease. Pressure is exerted through the vertical members onto the longitudinal face of the beam. The force is then transferred to both resilient hooked arms substantially equally. By having the arms free from the vertical members, they are able to flex freely around the grid face and engage simultaneously. No &#34;rocking&#34; of the face of the beam against the face of the grid is necessary to attach the beam to the grid. 
     The beam may be either factory or field applied. Having a universal shape for the attachment portion, regardless of the decorative face, lends itself to automated assembly. No matter what the design of the profile may be, the consistency of the attachment portion provides a place to capture the part for robotic assembly. 
     The beam may be extruded, molded, or machined from plastic, wood, metal, composite materials or any material with sufficient flexibility as a thin member to allow the beam to snap over the tee grid. Preferred is a material with low thermal expansion (Coefficient of Thermal Expansion of less than or equal to 3.0×10 -5  in/in° F.) similar to the grid. In this way, the beam does not move, warp, or gap with changes in ambient temperature once it is applied to the grid. 
     This invention will bring a new ease to designing and manufacturing grid. Metal roll forming, which is typically used to produce grid, would have required a new roll-forming mill for each design desired on the grid face. A new mill is a costly investment. To change from one design product to another would be quite expensive and time consuming. With the present invention, new roll formers are no longer required since no change is made to the grid. To change the appearance of the grid using the present invention, one simply applies a different three-dimensional decorative element or beam to the tee grid. The saving of time, money and effort is substantial. 
     Furthermore, by using a method other than roll forming, permits the formation of complex designs for the decorative element of the beam. This flexibility, in turn, lends itself to creating visually integrated ceiling systems. The ceiling board could be cut to complement the decorated grid visually. 
     Also, the beams of this invention could be designed to be compatible with tegularized ceiling board edge details as well as with flush panels. For larger or longer beams extending beyond the face of the tee grid, the ceiling board could be specially cut along its edge so that the board may rest on the tee-shaped ceiling support grid. This synergy of the ceiling and grid greatly enhances the overall appearance of an accessible ceiling. Alternatively, the board could be cut to rest on parts of the beam directly. 
     A critical element of a ceiling suspension system is the intersection of members that are perpendicular to one another, e.g., where four ceiling boards meet. To accommodate any profile that the three-dimensional element or beam might have, the present invention may utilize a double miter at the end of each profile in the intersection. This feature is profile independent, thus providing a universal intersection. In addition, the appearance is tailored and identical at each intersection in the ceiling. No further notching of the beams is required, either at the factory or on the job site, to allow clearance for the intersection of the support grid. The underlying tee-shaped grid may still intersect in a flush manner as is typical for this type of suspension system, but this unattractive intersection would not be visible from the room below since the mitered beams would cover it. 
     The advantages of the present invention may be summarized, as follows: 
     1. It uses less material than the hollow beam of U.S. Pat. No. 4,848,054. 
     2. Since the attachment mechanism may not be integral with the vertical member, it is easier to snap the beam onto the tee grid (no &#34;rocking&#34; is required to engage) than the hollow beam of the prior art. 
     3. The decorative face of the beam does not have to be the same size as the tee grid face. 
     4. The flexibility of design allows coordination between the design of the ceiling board with the design of the beam resulting in a distinct improvement in accessible ceiling appearance. 
     5. By using thermally stable material to manufacture the beam permits its application in the factory, as well as on site, without the elements of the beam &#34;drifting&#34; on the tee grid due to exposure to changes in temperature during shipping or at the installation site. 
     6. The double mitered intersection will require no notching of the beams to accommodate the underlying tee grid intersection. In addition, the double miter will provide an improved, tailored appearance. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more clearly understood by referring to the drawings and the detailed description that follows. 
     Fig. 1 is a cross-sectional view of a beam of this invention in an initial position in the process of being installed onto conventional inverted T-bar rail. 
     Fig. 2 is a cross-sectional view of the beam shown in FIG. 1 after installation on the T-bar rail. 
     Fig. 3 is a cross-sectional view of a beam installed on a T-bar rail, along with subceiling panels in place, the beam having the specially designed decorative element integral therewith. 
     FIG. 4 is a bottom view of the subceiling at the mitered intersection of four beams, each of which is shown in cross-section in FIG. 3; 
     FIG. 5 is a top view, in perspective, of the mitered intersection of two runner beams and two cross beams of FIGS. 3 and 4; 
     FIGS. 6-15 are cross-sectional views of beams having a variety of specially designed decorative elements. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 is a cross-sectional view showing the configuration of a beam 10 constructed in accordance with the present invention. Beam 10 is basically composed of two associated elements: the decorative elements 13, which may be integral with, or attached to, the substantially resilient fastening element. The fastening element is composed of a substantially horizontal flat or face portion 11 adapted to contact the outer surface of the T-bar and having hooked arms or return flanges 12a and 12b along each upper edge integral with the face portion 11 and extending inwardly. 
     Beam 10 may be fabricated from metal, wood, etc., but preferably it is fabricated from a flexible tough plastic such as polypropylene, high density polyethylene, an acrylic copolymer or homopolymer, etc. 
     In FIG. 1, beam 10 is shown with the hooked arms or return flanges 12a and 12b flexed outwardly as the beam is being forced over the rolled flanged edges 16a and 16b of the &#34;T-bar rail&#34; 15. The inverted T-bar rails comprise the framework suspended in a grid pattern to support the square or rectangular panels that form the ceiling. They represent the type of inverted T-bar rails 15 that are currently used for both residential and commercial ceilings. The support wires, that serve to suspend the rails by being looped through an opening in the rails and then connected to the building structure above, are not shown. A relatively mild force applied by hand, as indicated by the arrow, holds return flanges 12a and 12b upwardly against the sides of the edges of flanges 16a and 16b, respectively. 
     FIG. 2 shows the beam 10 in its installed position. By continuing to apply the mild pressure, the return flanges or arms 12a and 12b ultimately snap over and rest on the flanges 16a and 16b and the flat portion 11 fits snugly against the outer surface of the &#34;T&#34; of the T-bar rail 15. Flat portion 11 acts as a strike plate to constrain any skewing or other movement of the beam 10. 
     In FIG. 3, the end portions of ceiling panels 17a and 17b are shown in place resting on return flanges 12a and 12b with the decorative elements 13 of beam 10 serving to provide a covering for the usually metal surface of the T-bar rail 15. The final result is a smooth, visually effective ceiling. 
     Various design elements associated with the other elements of the beam are shown in FIGS. 6 through 15. It will be noted that the elements 13 may extend from the flat portion 11 of the fastening element to a level where the decorative elements are below, above, or at the same level as the exposed surface of the ceiling panel. 
     FIG. 4 is a bottom view of the subceiling composed of ceiling panels 18 and mitered beams having the decorative elements 13 shown in FIG. 3. FIG. 5 is a top view of the four intersecting mitered beams shown in FIG. 4. It will be noted that although they are not shown, the inverted T-bar rails used as runners and cross members may be the standard &#34;unmitered&#34; rails currently employed for the suspended framework that constitutes the grid.