Abstract:
An indirect fluorescent lighting fixture arrangement for a suspended grid ceiling that includes elements that combine with the ceiling grid to form a fixture. A panel frame element engages the grid from below and simultaneously acts as part of the ceiling and part of the fixture.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a system that integrates an indirect light with a suspended grid ceiling. 
     2. Description of Related Art 
     Suspended ceilings having a metallic grid that supports panels in grid openings are common. Generally, in such ceilings, direct lighting fixtures replace panels in selected grid openings to provide room illumination. Such light fixtures are commonly simply open bottom boxes that have a number of fluorescent light tubes mounted therein, in parallel, with a translucent cover on the bottom of the box. The box is supported on the grid. In direct lighting, light from the tubes shines directly downward through the translucent cover into the room. Generally, the tubes are visible from below. Such direct form of fluorescent lighting is relatively inexpensive, but very plain and utilitarian, without much decorative effect. 
     An alternative type fluorescent lighting of an indirect, reflected, type is occasionally used with suspended grid ceilings. Such indirect lighting, wherein the fluorescent tubes cannot be seen, yields a glow over the room, which can be used to achieve desirable decorative effects. No translucent or other light passing covers, panes or lenses, are normally used in this type of lighting, with the light shining through open space into the room after being reflected. 
     In one form of indirect lighting, the tubes are positioned below the ceiling panels of the suspended ceiling, and reflect against the ceiling into the room. Opaque shields conceal the tubes from view from the room below. Such installations are generally custom designed and installed, with attendant, generally extensive, expense. 
     Efforts have been made to provide indirect lighting fixtures that can be supported in grid openings as in direct lighting fixtures, to avoid the expense of custom designing and installing indirect lighting which reflects against the ceiling. In this form of indirect lighting in suspended grid ceilings, the fixture reflects light through a grid opening itself, as in U.S. Pat. No. 5,709,460. In such patent, the tubes are positioned above and behind panels adjacent the openings, and thus concealed from view from below. The light is reflected from a dome over the opening and tubes, into the room below, through the grid opening. A mask is optionally secured to the fixture to reduce the area of the opening through which the reflected light travels, and to further conceal the light tubes from view from below. The fixture, including the reflector dome, rests on the grid beam flanges. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is for an indirect light that includes elements that combine with a grid beam frame in a suspended ceiling to form the fixture. 
     The invention uses a special panel frame that engages the grid frame that surrounds an opening in a suspended grid ceiling. This panel frame simultaneously serves as (1) a decorative and functional part of the suspended ceiling, and (2) an element in the indirect lighting fixture that (a) masks the tubes from viewing from below, and (b) permits light reflected from the tubes to pass unobstructed into the room below, and (c) when the fixture is designed to be sound absorbing, the panel frame absorbs the sound, and permits sound to reach the sound absorbing surfaces within the fixture. 
     The panel frame or coffer, in the event the panel is recessed, of the invention, is secured to the grid frame, from below, without interference from the other elements of the fixture, which rest on the grid frame, above the grid. 
     The panel frame element of the invention can be in the form of a relatively elaborate coffer frame, or simply a panel substantially the same as the remaining panels in the ceiling, except for an opening in the panel frame that permits the reflected light to shine through and sound to reach an absorbing surface, when a sound absorbing surface is optionally present within the fixture. The panel frame design is chosen to be compatible with the rest of the suspended ceiling. 
     The panel frame or coffer of the invention is inserted from below, just as the remaining panels in the ceiling are inserted, after the dome and light frame are in place. 
     With or without the lights on, the panel frame element simultaneously serves as both a decorative and functional part of the ceiling, and a part of the indirect light fixture that serves to mask the tubes. 
     The ceiling grid beams form a grid frame that surrounds the grid opening in which the light fixture is located. The grid frame serves as a structural element in the ceiling, and as the element in the light fixture that supports the light frame and dome, and connects the panel frame to those light elements. 
     The entire light fixture of the invention also serves as a decorative element in the ceiling, with or without the lights on, as well as a functional element wherein the grid opening is enclosed by the panel frame, light fixtures, and dome. When the dome and/or the panel frame are made of sound absorbing material, the light fixture of the invention also contributes to the acoustical effects of the grid ceiling. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view taken from below of a suspended grid ceiling, with the light fixture of the invention in place in a grid opening. 
     FIG. 2 is a partial exploded perspective view of the fixture of the invention as shown in FIG.  1 . 
     FIG. 3 is a fragmentary exploded perspective view of the support bracket on the light frame element of the fixture of the invention. 
     FIG. 4 is a sectional elevation taken on the line  44  in FIG.  1 . 
     FIG. 5 is a sectional elevation taken on the line  55  in FIG.  1 . 
     FIG. 6 is a fragmentary plan view, taken from below on line  6 — 6  of FIG. 5, of the light frame and dome of the light fixture resting on the grid frame. 
     FIGS. 7 through 9 are sectional elevations of the panel frame of the invention being inserted into the grid frame. 
     FIG. 7 shows the first step in inserting the panel frame. 
     FIG. 8 shows the second step in inserting the panel frame. 
     FIG. 9 shows the final step in inserting the panel frame, and the panel frame in place in the grid frame. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A suspended ceiling  20  has a grid  21  of beams  22  that intersect to form multiple rectangular openings  23 . Openings  23  are generally, when the present invention is used, square, of a 24″×24″ size. Acoustical panels or tiles  25  are set in the openings. The ceiling functions to enclose the room overhead and to decorate the room to the extent desired by the use of colors, textures, and designs in the panels and optionally in the grid. The grid  21  can be fully or partially exposed to view from below, or totally concealed. Such ceilings are well known. 
     The beams  22  of the grid  21  include main runner  26  and cross runners  27  that interconnect. 
     The entire suspended ceiling  20  including grid  21 , and panels  25 , is suspended from a structural ceiling by wires anchored in the structural ceiling and connected to holes in the main runners  26  of the grid  21 . 
     The beams  22  have a cross-sectional shape in the form of an inverted T, with a bulb  28  at the top, a vertical web  30 , and horizontally extending flanges  31  at the bottom of the beam. 
     As is well known, the ceiling tiles or panels  25  are supported on the flanges  31  of the T in each rectangular opening  23 . The panels  25  are inserted into each grid opening  23  from below the grid  21  when constructing the suspended ceiling  20 . 
     The fixture  40  of the invention is located in one of the grid openings  23  in the suspended ceiling  20 . A ceiling panel  25  is omitted from such opening. 
     The fixture  40  is a combination of a dome  41 , a light frame  42 , a grid frame  43 , and a panel frame  45 . 
     Fixture  40  has at the top a reflecting dome  41 . The dome  41  has a flat, horizontal perimeter edge strip  46 . The dome  41  then rises in curved fashion from the strip as seen particularly in FIGS. 4 and 5, into a flat or curved roof section at the top of the dome  41 . The dome  41  is preferably formed, as by molding from plastic, in one piece, and has a light reflective undersurface of a color desirably chosen to harmonize with the remainder of the fixture and ceiling. The dome  41  can optionally be made of sound absorbing material. 
     The dome  41  rests on a light frame  42  that extends horizontally below the dome  41 . The fixture  40  is of rectangular shape, usually square, in plan view, and conforms to the interior of the grid opening  23  in which the fixture  40  is located. 
     The light frame  42  has four sides designated first opposing sides A and B and intervening opposing sides C and D. 
     One or more sides of the light frame  42  itself has a basic structural member  47  for supporting the fluorescent tube  48  which is essentially a channel member having therein the necessary ballast and starter for a fluorescent tube  48 , along with receptacles at the end for receiving the fluorescent tube contacts. Such structure is common in the prior art. The tubes  48  may be of an appropriate length for the grid opening  23  (for example, 18, 24 or 48 inches). The tubes  48  may be on all four sides of the light frame  42 , or only on two opposing sides, as for instance two opposing 48″ (inch) tubes in a 24″×48″ opening, or even only on one side. Generally, the light frame  42  would have tubes  48  on each side, when the light frame  42  is for a 24″×24″ opening. The channels of the light frame  42  are structurally connected at their corners. On a side where there is no tube channel, a simple structural bar is inserted. Suitable corner members connect the tube channels and structural bars. The light frame  42  is thus essentially an open rectangle with one or more fluorescent tubes  48  along one or more of the sides. 
     Of importance in the invention are supporting brackets  50 , which are affixed to the light frame  42  on the underside and are designed to rest on the bottom flange  31  of the grid beams  22  that extend around the four sides of the grid opening  23 , and to provide clearance between the light frame  42  and grid frame  43 . The brackets  50  optionally have an angle cutout that forms a shoulder  51  around the inner perimeter of the flange  31  around the grid opening  23 , which positions the frame  42  horizontally within and above the opening. 
     The brackets  50  are affixed only on first opposing sides A and B of the frame, so that they rest only on the flanges  31  of corresponding first opposing sides A and B in the grid opening  23 . The brackets  50  support the light frame  42  above the flanges  31  of grid frame  43  around grid opening  23  and provide clearance between the bottom side of the light frame  42  and the upper surfaces of the flanges  31  of grid frame  43 . 
     Of particular importance to the invention is that the flanges  31  on intervening opposing sides C and D of the grid opening  23  that correspond to intervening opposing sides C and D of the light fixture  40 , are free of any interference or obstruction to the insertion of another element of the invention, the panel frame  45 . 
     The panel frame  45  is of a design that is compatible with the rest of the ceiling. It has a perimeter section  52  that serves to hide the fluorescent tubes  48  from viewing from below, and a central opening  53  that permits reflected light to enter the room. The panel frame  45  may be of a coffered design  65 , wherein there is a recessed portion  66  about the central opening  53  that recedes up into the ceiling. The recessed portion  66  may be stepped as at  67  to provide a pleasing appearance and structure that further hides the tubes  48  from direct view from below. The panel frame  45  may be formed of the same composition as the rest of the ceiling panels or tiles  25 , or may be of a separate material such as metal, plastic, or of a relatively dense compacted woodchip, or other suitable material, molded or otherwise, of the same or different color as the rest of the ceiling. The composition of panel frame  45  may be chosen to be sound absorbing. 
     The panel frame  45  has first opposing sides A and B, and intervening opposing sides C and D which correspond to the like designated sides on the light frame  42 , and the grid frame  43 . 
     The panel frame  45  of the fixture  40  of the invention must have a perimeter thickness that permits an edge configuration on intervening opposing sides C and D to engage flanges on intervening opposing sides C and D in the grid opening  23  in the manner shown in FIGS. 7 through 9. The panel frame  45  must be capable of being inserted from below, with the dome  41  and light frame  42  in place, without interference from those elements. This is accomplished with a panel frame  45  having a configuration on intervening opposing sides C and D that permit the panel frame  45  to be shifted into place in the confined area below the light frame  42  and above flanges  31 . 
     As seen in FIGS. 7 through 9, each of the edges C and D of the panel frame  45  has a top shoulder  55 , a first recessed portion  56 , a second recessed portion  57 , and a lower lip  58 . 
     The panel frame  45  is inserted into place by bringing side C up into position as shown by the arrow in FIG. 7, until lower lip  58  contacts flange  31 . The panel frame  45  is then shifted to the left as seen by the arrow in FIG.  7  until the panel frame  45  is in the position seen in FIG.  8 . The panel frame  45  is then moved upward as shown by the arrow in FIG. 8, on opposing side D, and then shifted in the direction of the arrow in FIG. 9 into the position shown in that Figure. 
     No interference is encountered from the edges A and B of the panel which have a stepped cut back  59  as shown in FIGS. 4 and 5. Edges A and B on panel frame  45  do not support the panel frame  45  from the adjacent flanges in the grid frame  43 , but only serve to cover from view the grid  21  and light frame  42 , including brackets  50  by means of a protruding lower lip  60 . 
     To gain access to the fluorescent tube  48 , light frame  42 , and dome  41 , it is merely necessary to reverse the steps stated above to remove the panel frame  45 . 
     With the lights on, the panel frame  45  permits indirect reflected light and sound to pass through the panel frame central opening  53 , while shielding the tubes  48  from direct view. When the material of the dome is sound absorbing, sound will be absorbed in the dome. The panel frame  45  serves to so shield the tubes  48 , while simultaneously acting with the other panels  25  in the ceiling to provide a decorative and functional effect. With the light out, the panel frame  45  continues to provide decorative and functional ceiling effect. 
     The grid frame  43 , the panel frame  45 , the light frame  42  with its brackets  50 , and the dome  41 , combine to form the light fixture  40 . 
     The brackets  50  on the light frame  42  support the light frame  42  on two opposing sides of the opening, leaving the intervening sides of the opening free to support panel frame  45 . 
     The panel frame  45  can be inserted from below. The panel frame  45  can be formed of the same material as the adjacent ceiling panels. 
     The edge detail on intervening opposing sides C and D of panel frame  45  can also be that disclosed in co-pending application Ser. No. 09/141,407, incorporated herein by reference. Such edge detail also permits, by a series of shifts and rotations, the panel frame  45  to be positioned in the light fixture  40 . 
     Since the installation and removal procedure of the panel frame  45  of the present invention requires virtually no activity above the beam flanges  31 , the fixture  40 , once installed, can be serviced with a minimum of difficulty. 
     In the event it is desired to remove the reflecting dome  40 , as for instance for cleaning, the dome can be reached through an adjacent grid opening  23  by merely removing the adjacent panel  25 , and retrieving and then reinserting the dome  41 , which merely sits on the light frame  42 . 
     The dome  41 , the light frame  42 , and the panel frame  45 , described above, can be prefabricated and then combined with grid frame  43  during installation to form the fixture  40  of the invention. 
     The fixture in place provides a pleasing appearance, since the panel frame  45  is compatible with the rest of the ceiling, and through various designs, made to standout from or blend with the other panels. 
     The fluorescent tubes  48  are hidden from direct glare into the room below, with the light reflected in a soft manner that does not discourage viewing from below through central opening  53  of panel frame  45 , to dome  41 .