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BACKGROUND OF THE INVENTION  
       [0001]     The invention relates to suspended ceiling systems and, in particular, to specialized panels for such systems.  
       PRIOR ART  
       [0002]     In contemporary commercial buildings, grid type suspended ceilings are widely, if not almost universally, used. In most suspended ceilings, the ceiling grid pattern is interrupted by light fixtures and, often, conditioning air vents, sprinkler heads, speakers, utility conduits, exit signs, and so forth. Architects strive to integrate these necessary service related elements into the grid to achieve a simple and, therefore, more aesthetically pleasing appearance.  
         [0003]     Frequently, elongated light fixtures and/or air vents are longitudinally aligned and spaced along a line that interrupts the regular rectangular grid pattern, ordinarily being parallel to one or the other directions of the grid. Where these fixtures are of a size, typically a width, different from a standard grid module dimension, it has been a practice to custom make cross tee grid members of a nominal length equal to the nominal width of the fixture. That is, the spacing of the main runners or tees conforms to or straddles the fixture and, in turn, the custom made cross tees conform to the desired spacing of the main runners or tees. This customization of the cross tees can be expensive, if not prohibitively expensive. Even when customized cross tees can be economically justified, there remains the problem of fashioning a ceiling tile or panel to an appropriate custom size. With traditional grid and panel systems, it can be difficult for a single trade to complete a ceiling grid installation without interruption due to the overlapping of tasks of different trades. For example, the ceiling installation can involve issues of the division of labor between carpenters and sheet metal workers, for example.  
       SUMMARY OF THE INVENTION  
       [0004]     The invention involves a ceiling panel that constitutes a visible part of the ceiling surface and that also provides the structural function of a cross tie between main runners or tees. In the disclosed arrangements, the panel is a rectangular sheet metal unit that has connectors at each of its four corners for engaging the webs of a pair of parallel main tees. The connectors may be formed integrally with the sheet metal of the panel or may be separately formed and fixed to the panel. The connectors are preferably blade-like in configuration so that they can be inserted into the conventional connector receiving slots in the webs of the parallel main tees. The panel connectors in cooperation with the panel itself are arranged to hold the main tees in parallel alignment, preferably against both compressive and tensile forces.  
         [0005]     The panel can be arranged to work with and/or without the module dimensions of the grid. Besides affording a broad range of rectangular shapes and sizes, the panel can be arranged with a variety of surface treatments including textures, contours extending above and/or below the plane of the surrounding grid, and small and large perforations of any desired pattern or spacing. Among other advantages, the panel can have punching for sprinkler heads, can conceal public address speakers, and can act as a return air grille for HVAC systems, thus further organizing the ceiling plane in an aesthetic way while providing these utilities or functions.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is an exploded perspective fragmentary view of a ceiling system employing a cross panel constructed in accordance with the invention;  
         [0007]      FIG. 2  is an elevational view of the cross end of a cross panel;  
         [0008]      FIG. 3  is a view similar to  FIG. 2  showing a second embodiment of a cross panel;  
         [0009]      FIG. 4  is a somewhat schematic fragmentary perspective view from below of a suspended ceiling system showing the relationship of cross panels and a surrounding grid; and  
         [0010]      FIG. 5  is a somewhat schematic fragmentary perspective view of a suspended ceiling system showing cross panels of configurations different than those of  FIG. 4 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]      FIG. 1  shows a ceiling cross panel  10  in a fragmentary exploded perspective assembly view with a pair of parallel main tees  11 . The illustrated cross panel  10  is formed of a single sheet of light gauge sheet metal such as aluminum or mild steel. In the illustrated example, the cross panel has a face  12  visible from below the ceiling and having a rectangular periphery. The face, in the illustrated case, is perforated with a multitude of small regularly spaced holes throughout substantially its full area. The holes or perforations  13  can serve to pass sound and/or permit air circulation through the cross panel  10 . The panel face  12 , at least, can be painted or otherwise finished as desired.  
         [0012]     Opposed edges  14  of the cross panel, sometimes referred to hereinafter as longitudinal edges, are parallel with the longitudinal direction of the main tees  11 . The longitudinal edges  14  each have an associated small upward step  16  ( FIG. 2 ), a relatively narrow horizontal shelf  17 , and a vertical flange  18 . In the illustrated case, the step  16 , shelf  17  and flange  18  extend substantially along the full longitudinal extent of the edges  14 . The resulting vertical offset of the shelf  17  above the face  12  allows the face to sit flush with faces  19  of the main tees  11  and, ordinarily, faces of the remainder of the grid system as shown in  FIGS. 2 and 3 . While the illustrated tee  11  is of a narrow design, the cross panel step  16  and shelf  17  can be configured for use with tees of other widths. Alternatively, the step  16  can be omitted and the cross panel can be simply formed as a “lay-on” panel. The vertical flange  18  extending perpendicularly to the plane of the panel face  12  serves to stiffen the cross panel  10 .  
         [0013]     Opposed edges  21  of the cross panel  10 , sometimes referred to hereinafter as cross edges or cross sides, each have an associated vertical or upstanding flange  22  extending along the full cross length of the cross panel  10 . Adjacent each corner of the rectangular panel face  12 , is a connector  23  extending, in the manner of a cantilever, from a respective end of a cross flange  22  laterally beyond the panel face  12  and beyond the adjacent stiffening flange  18 . The connectors  23 , preferably, are identical and each is blade-like with a vertical extent substantially greater than its thickness or horizontal extent. The connector  23  at its distal end has a depending hook configuration  24  with an abutment edge surface  26  that faces generally laterally inwardly towards the main part of the cross panel  10 , i.e. the cross panel proper. A clearance notch  27  exists between the hook edge surface  26  and the adjacent part of the associated end of the flange  22 . Above and slightly laterally inwardly of the hook or catch surface  26  is an outwardly facing abutment edge surface  28 . A crease  29  forming an inward rib running lengthwise of the flange  22  and partially along the connectors  23  serves to stiffen these elements.  
         [0014]      FIG. 2  illustrates the cross panel  10  in an installed condition between a pair of parallel grid members or main tees  11 . Normally, the grid members will be so called main runners or main tees with lengths typically greater than a module dimension. For example, the tees can have lengths of 10 or 12 feet while a module of a ceiling grid may be typically two, four or five feet. Each connector  23  is inserted through a receiving slot  31  formed in a web  32  of a respective main tee  11 . This insertion is accomplished by raising the connector  23  so that the hook  24  passes over the lower edge of the slot  31  while the top of the tee  11  is tilted away from the panel  10  and the hook is allowed to drop down to catch the web  32  on its side opposite the panels. The cross panel  10  ordinarily with identical cross panels or cross panels of the same cross-wise dimension, is sized to establish and maintain a desired uniform parallel spacing between the main tees  11 . Inspection of  FIG. 2  shows that forces tending to separate the main tees  11  are resisted by the hook edge surfaces  26  and forces tending to move the tees towards one another, i.e., in convergence, are resisted by the abutment surfaces  28 .  
         [0015]     From this explanation, it will be understood that the cross panel serves both as a visible appearance panel in a ceiling distinguishable from the narrow strip of a grid tee, and as a cross tie member with the function of a traditional grid cross tee. The cross panel can additionally align and/or retain the parallel main tees in end-to-end or longitudinal alignment and can assist in maintaining the grid square such that the tees intersect at right angles.  
         [0016]     Typically, but not necessarily, the slots  31  for the connectors  23  on the tees  11  are on standardized centers, e.g. every six inches. Where a panel  10  is longer than this center-to-center distance and there is a cross tee connector  123  in an intermediate slot or slots  31 , the panel flange  18  can be formed with a notch or clearance hole or holes  41  for clearance of the connector(s).  
         [0017]     The cross panel  10  can be configured in various cross-width-to-length ratios. The width established between main tees  11  by the flanges  22  and connectors  23  can be less than (as shown in  FIG. 2 ) equal to, or greater than the other dimension of the cross panel, i.e. the distance between the cross flanges  22 .  
         [0018]      FIGS. 4 and 5  illustrate typical variations in the size and configuration of a cross panel  10 . In  FIG. 4 , the cross panels  10  are of different dimension along the length of the main tees  11 . As also shown in  FIG. 4 , the cross panel  10  can be arranged with its cross edges or ends, as represented by the vertical flanges  22 , located on or off the grid module centers of cross tees  36 .  FIG. 5  illustrates a condition where the cross panels  10  are greater in length than a grid module between cross tees  36 . One cross panel  10   a  is modified, by way of example, by incorporating a hole  37 , sized to accommodate a sprinkler head. As a general rule, a cross panel  10  will have a rectangular profile in plan view, a square cross panel being considered a species of a rectangular cross panel. It will be appreciated that the face  12  of a cross panel may be non-planar, projecting above and/or below the plane of the main part of a ceiling structure. Additionally, the cross panel face  12  can be imperforate or perforate, and finished as desired.  
         [0019]     Referring to  FIG. 3 , a modified cross panel  110  is disclosed. The cross panel  110  can have the same general geometry as the cross-panel  10  described with reference to  FIGS. 1 and 2  with the exception that the connector  123  on each corner of the cross panel  110  is a separate part fixed to the sheet metal forming the cross panel  110  proper. The connector  123  can be of the type disclosed in U.S. Pat. No. 5,761,868, the disclosure of which is included herein by reference, or any other similar clip that is normally assembled to ceiling grid cross tees as is known in the industry. The connector  123  is permanently clinched or otherwise fixed on the end of a respective cross flange  122  in a known manner. The connector  123  can be coupled with an identical connector assembled through a common slot  31  or hole in the web  32  of a main tee  11  from the side of the main tee opposite the side at which the cross panel  110  is situated. Each connector  123  is capable of resisting forces tending to either spread or converge the main tees  11  to which they are connected whether or not coupled to an opposed connector at their respective main tee slots  31 . A rearwardly facing edge surface  126  resists separation and a forwardly facing edge surface  128  resists convergence between the main tees  11 .  
         [0020]     While the invention has been shown and described with respect to particular embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to those skilled in the art all within the intended spirit and scope of the invention. Accordingly, the patent is not to be limited in scope and effect to the specific embodiments herein shown and described nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.

Summary:
A cross panel for a grid type suspended ceiling comprising a sheet metal body forming a rectangular face adapted to close the space between the flanges of a pair of parallel grid tees. The panel has four connectors each adjacent a respective corner of the panel face and adapted to extend through a slot in the web of the adjacent grid tee for interlocking the panel to the tees in a manner that maintains the parallel spacing and alignment of the tees and affords a simple, aesthetically pleasing appearance.