Patent Publication Number: US-6219977-B1

Title: Tubular skylight with round-to-square adaptor

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to apparatus for naturally illuminating rooms, and more particularly to tubular skylights. 
     BACKGROUND 
     Tubular skylights have been provided for illuminating rooms inside buildings with natural light. Not only do tubular skylights thus save electricity and, concomitantly, are environmentally benign, but they illuminate rooms in a pleasing way using natural sunlight instead of 60 cycle electric light. An example of a commercially successful tubular skylight is disclosed in U.S. Pat. No. 5,099,622, assigned to the same assignee as the present invention and incorporated herein by reference. 
     A tubular skylight includes a roof-mounted, dome-like transparent cover. The cover is mounted on the roof of a building by means of a flashing. An internally reflective tube depends downwardly from the roof to the ceiling of the room sought to be illuminated, and the bottom of the tube is covered with a disk-shaped light diffuser that is positioned at the ceiling. The round cross-sectional shape of the tube promotes light reflectivity and transmission down the tube, into the building. 
     In most existing tubular skylights, the ceiling dry wall supports the diffuser and the tube. To install a tubular skylight, a circular hole is cut in the existing ceiling dry wall and another hole is cut in the roof, and then the skylight positioned and mounted as described above. 
     The present invention recognizes that tubular skylights can be used in applications other than in conventional ceiling dry walls. For example, the present invention recognizes that tubular skylights can be used to illuminate relatively larger buildings that have ceilings defined in part by rectangular grids of metal support joists. The grids are used to support rectangular-shaped ceiling panels. 
     As understood by the present invention, the bottom portion of a tubular skylight should be shaped complementarily to the ceiling opening with which the skylight is engaged. In the case of conventional ceilings made of dry wall, the ceiling opening is formed to accommodate the round cross-sectional shape of the skylight. In the case of larger ceilings having rectangular support grids, however, the opening with which the skylight must be engaged, namely, one of the rectangular areas formed by the grid, is not designed with tubular skylights in mind, but rather with the rectangular shape of conventional ceiling panels in mind. As intimated above, this problem cannot be solved simply by making the skylight parallelepiped-shaped, because a skylight with a rectangular cross-section will not transmit light down to the ceiling as efficiently as will a tubular skylight. Moreover, the tubular shape of skylights is widely accepted and indeed ingrained in the industry. The present invention has both recognized the problem of installing skylights in a ceiling grid, and provides the below-disclosed solution. 
     SUMMARY OF THE INVENTION 
     A tubular skylight is disclosed for a building having a roof with a skylight flashing and at least one ceiling grid below the roof for supporting a ceiling above a room, wherein the ceiling grid defines at least one rectangular opening. In accordance with the present invention, the skylight includes a transparent cover that is engageable with the flashing, and a tube assembly depending downwardly from the flashing. The tube assembly has an upper end covered by the cover. An adaptor couples the tube assembly to the rectangular opening. 
     In a preferred embodiment, the adaptor is hollow, and the inside surface of the adaptor is covered with a reflective coating. The preferred adaptor defines a ring-shaped tube segment that is configured complementarily to the tube assembly and that is engaged with the tube assembly. Moreover, the adaptor includes a rectangular-shaped ceiling segment that is configured complementarily to the rectangular opening and that is disposed on the grid. A rectangular-shaped light diffuser is coupled to the rectangular-shaped ceiling segment of the adaptor. 
     As disclosed in detail below with respect to the preferred embodiment, the adaptor is formed with an intermediate segment that is at least partially frusto-pyramidal shaped. The intermediate segment connects the ring-shaped tube segment of the adaptor to the rectangular-shaped ceiling segment of the adaptor. In a particularly preferred embodiment, the intermediate segment includes a lower intermediate portion defining a right regular pyramidal frustum and an upper intermediate portion defining a circular top edge. 
     In another aspect, an adaptor for interconnecting a tubular skylight and a rectangular-shaped opening of a ceiling grid that has a rectangular-shaped diffuser disposed therein includes a hollow tube segment. As envisioned by the present invention, the tube segment is circular-shaped to facilitate coupling the tube segment to the tubular skylight. Also, the adaptor includes a hollow ceiling segment is rectangular-shaped to facilitate coupling the ceiling segment to the diffuser. 
     In still another aspect, a method is disclosed for mounting a tubular skylight in a building having a roof and a ceiling grid below the roof. The method includes attaching the skylight to the roof, and disposing a diffuser in an opening of the grid. The tube of the skylight is then coupled to the diffuser. 
     The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the tubular skylight of the present invention in an exploded relationship with a ceiling grid, with portions of the ceiling grid cut away for clarity; 
     FIG. 2 is a perspective view of the square-to-round adaptor; 
     FIG. 3 is a cross-sectional view as seen along the line  3 — 3  in FIG. 2; and 
     FIG. 4 is a perspective view showing the details of how the adaptor and diffuser are supported, with portions broken away for clarity. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIG. 1, a tubular skylight is shown, generally designated  10 , for lighting, with natural sunlight, an interior room  12  having a ceiling support grid  14  in a building, generally designated  16 . FIG. 1 shows that the grid  14  includes orthogonal metal or plastic T-shaped joists  17  that together define plural rectangular-shaped openings  18 . Each opening  18  can define a two foot by two foot square, although other rectangular shapes and dimensions are contemplated herein. In accordance with the present invention, most of the openings  18  support ceiling panels but one of the openings, designated  18   a  in FIG. 1, can engage the skylight  10 . 
     Describing the skylight  10  from top to bottom, as shown in FIG. 1, the skylight  10  includes a roof-mounted cover  20 . The cover  20  is optically transmissive and preferably is transparent. In one embodiment, the cover  20  can be the cover disclosed in co-pending U.S. patent application Ser. No. 08/957,513, filed Oct. 24,1997 for an invention entitled “LIGHT-COLLECTING SKYLIGHT COVER”, owned by the same assignee as the present invention. Or, the cover  20  can be other suitable covers, such as the covers marketed under the trade name “Solatube” by the present assignee. 
     The cover  20  is mounted to the roof of the building  16  by means of a flashing  22 . The flashing  22  includes a flange  22   a  that is attached to the roof by means well-known in the art, and a curb  22   b  rises upwardly from the flange  22   a  and is angled relative to the flange  22   a  as appropriate for the cant of the roof to engage and hold the cover  20  in the generally vertically upright orientation shown. A seal  23  can be positioned between the curb  22   b  and the cover  20  to effect a dust and water seal between the cover  20  and the flashing  22 . 
     As further shown in FIG. 1, an internally reflective metal tube assembly  24  is connected to the flashing  22 . The tube assembly  24  extends to the grid  14  of the interior room  12 , with the top of the tube assembly  24  being covered by the cover. Per the present invention, the tube assembly  24  directs light that enters the tube assembly  24  downwardly into the room  12 . The tube assembly  24  can be made of a metal such as a type  1150  alloy aluminum, or the tube assembly  24  can be made of fiber or plastic or other appropriate material, with the interior of the tube assembly  24  being rendered reflective by means of, e.g., electroplating, anodizing, metalized plastic film coating, or other suitable means. 
     In one preferred embodiment, the tube assembly  24  includes a cylindrical hollow lower tube segment  26  that is telescopically received in a cylindrical hollow upper tube segment  28 , with the upper tube segment  28  in turn being engaged by means known in the art with the flashing  22 . The tube segments  26 ,  28  can be held together by taping the joint  30  that is established between the segments  26 ,  28 . Even when taped, the segments  26 ,  28  can move axially relative to each other to absorb thermal stresses. An expansion seal (not shown) such as the one described in co-pending U.S. Pat. application Ser. No. 08/969,923, owned by the present assignee and incorporated herein by reference, can be positioned radially between the segments  26 ,  28  to permit longitudinal (i.e., axial) relative motion between the segments  26 ,  28 , while establishing a seal between the segments  26 ,  28 . 
     FIGS. 1 and 2 best show the present inventive combination for coupling the lower tube segment  26 , which defines a circular cross-section, with the rectangular opening  18   a  that is defined by the ceiling grid  14 . A hollow adaptor  30  defines an inside surface  32 , and the inside surface  32  is covered with a reflective coating  33 , as is the case with the assembly  24 . Furthermore, the adaptor  30  includes a ring-shaped tube segment  34  that is configured complementarily to the tube assembly  24  and that is engaged therewith by, e.g., taping or other means. By “configured complementarily” is meant that the tube segment  34  has the same shape (e.g., circular) and approximately same diameter (e.g., twenty inches) as the tube assembly  24 . As can be appreciated in reference to FIG. 2, the preferred tube segment  34  has a vertical wall  36 . 
     Additionally, the adaptor  30  includes a rectangular-shaped ceiling segment  38  that is configured complementarily to the rectangular opening  18   a  and that is coupled to the grid  14 . In three dimensions, the ceiling segment  38  is a parallelepiped, and when the opening  18   a  is square, the ceiling segment  38  likewise defines a square cross-section. A rectangular-shaped light diffuser  40  covers the bottom of the ceiling segment as shown, it being understood that either the light diffuser  40 , or ceiling segment  38 , or both can be attached to the grid  14 . The preferred method of coupling the adaptor  30  with light diffuser  40  to the grid  14  is discussed in greater detail below with reference to FIG.  4 . 
     As recognized by the present invention, were the tube segment  34  contiguous to the ceiling segment  38 , the light passing through the diffuser  40  would not appear to pass through the entire rectangular area of the diffuser  40  as desired, but instead would appear as a circular pattern covering only part of the area of the diffuser  40 . This would render an artificial and undesirable appearance. 
     Accordingly, a hollow intermediate segment  42  is provided to connect the ring-shaped tube segment  34  to the rectangular-shaped ceiling segment  38 , and to reflect light passing through the intermediate segment to more evenly distribute light transmission through the diffuser  40  than would otherwise occur without the intermediate segment  42 . As shown in FIGS. 2 and 3, the intermediate segment  42  includes an upper intermediate portion  44  that defines a circular top edge  46 . The top edge  46  of the upper intermediate portion  44  is closely received in the tube segment  34  as shown, although if desired the tube segment  34  could be received in the upper intermediate portion  44 . 
     Additionally, a lower intermediate portion  48  that preferably defines, apart from its faceted edges, a right regular pyramidal frustum extends down from the upper intermediate portion  44 . Being a right regular pyramidal frustum, the lower intermediate portion  48  defines four walls that terminate in a square that is juxtaposed with the upper periphery of the ceiling segment  38 . To establish the round upper intermediate portion  44 , the edges  49  of the lower intermediate portion  48  are faceted as shown in accordance with sheet metal transition principles known in the art. 
     FIG. 4 shows one method for coupling the adaptor  30  and diffuser  40  to the grid  14 , it being understood that other methods can be used. As shown, the adaptor  30  is formed with a skirt  50  that rests on a horizontal portion  52  of one or more joists  17 . If desired, a resilient seal  54  can be sandwiched between the adaptor  30  and joist  17  as shown. 
     Additionally, the diffuser  40  can include a diffuser plate  56  that is supported in a diffuser housing  58 , and one edge of the diffuser housing  58  is pivotably attached to either the grid  14  or, more preferably, to the adaptor  30 . The opposite edge of the diffuser housing  58  is held by means of clips to the adaptor  30 , with the diffuser  40  thus being held to the adaptor  30  (or grid  14 ) in the same manner that a conventional ceiling tile is held to a ceiling grid. Alternatively, the adaptor  30  can be suspended from wires such that the bottom end of the ceiling segment  38  of the adaptor  30  is disposed in the periphery of the opening  18   a . In any case, both the adaptor  30  and diffuser  40  are coupled, directly or indirectly, to each other and to the grid  14 , with the diffuser plate  56  covering substantially all of the bottom opening of the adaptor  30 . 
     While the particular TUBULAR SKYLIGHT WITH ROUND-TO-SQUARE ADAPTOR as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and is thus representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more”.