Abstract:
A grid system is provided that is particularly suited for the suspended ceiling system that varies in the vertical plane. An elongated carrier tube is provided the spans substantially the width of the grid system that has a slot therein adapted to receive the strengthening bulb of a main runner. A clip is provided that seats on the carrier tube that has opposed faces for capturing the bulb of the runner, so as to secure the runner to the tube carrier.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/622,418, filed Oct. 27, 2004, which is incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   Suspended ceilings of various shapes and sizes are being increasingly used in order to add interest to various public spaces, such as retail outlets, contemporary office lobbies and halls, entertainment establishments, and the like. This has lead to the creation of suspended ceiling systems for defining spaces in which the ceiling panels lie in more than one plane, such as in vaults, transitions between different ceiling heights, islands, and waves. 
   One problem with such non-conventional ceiling systems is the difficulty of installing the suspending grid so that the runners for supporting the associated ceiling panels are maintained in accurate alignment. In particular, this difficulty has lead to increased time and cost for the assembly of such suspended ceiling systems. 
   Accordingly, by way of the invention described herein, a suspended ceiling system is provided that is particularly suited for providing a grid system that is curved in vertical plane, provides for accurate spacing and alignment of the grid elements, and facilitates quick assembly and installation of the assembled grid system. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a grid system for a curved suspended ceiling in accordance with the present invention. 
       FIG. 2  is a perspective view of a portion of a primary carrier in accordance with the present invention. 
       FIG. 3  is a perspective view of a splice for connecting primary carriers in accordance with the present invention. 
       FIG. 4  is a perspective view showing the splice of  FIG. 3  joining two primary carriers in accordance with present invention. 
       FIG. 5  is a perspective view of a portion of the grid system according to the present invention showing a clip for securing a primary carrier to a main runner. 
       FIG. 6  is an enlarged perspective view of the clip for securing the primary carrier to the main runner. 
       FIG. 7  is a perspective view of a portion of the grid assembly showing a connection of a primary carrier to a perimeter trim piece. 
       FIG. 8  is an enlarged perspective view of a clip for securing the primary carrier to the perimeter trim piece. 
       FIG. 9  is a perspective view of a portion of the grid system of the present invention showing the connection of a main runner to a trim piece. 
       FIG. 10  is an enlarged perspective view of a clip for securing a main runner to a trim piece. 
       FIG. 11  is a perspective view of a portion of the grid system showing two pieces of trim connected to each other by means of a splice clip. 
       FIG. 12  is an enlarged exploded perspective view of the splice clip for connecting two trim pieces together. 
       FIG. 13  is a perspective view of a hanger clip for securing the hanger wire to the primary carrier. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention comprises an assembly particularly suited for a curved suspended ceiling grid. With reference to  FIG. 1 , the system, generally designated  10 , includes main runners or tees  12  which are curved in a vertical plane to support either flexible panels  13  or preformed, lay-in panels (not shown), the latter requiring cross-tees between adjacent main tees. The curve may be either concave or convex with respect to the exposed side of the ceiling system. Edge or perimeter trim pieces  14  (which may be either curved or straight, as required to correspond to the shape of the main runners  12 ), having opposed interior slots define the perimeter of the suspended ceiling. Corner clips are used to secure the perimeter trim pieces to each other. However, the perimeter trim may be omitted, if desired, without departing from the invention. Each of the main runners, trim pieces and corner clips have previously been available from Chicago Metallic Corporation, assignee of the present application, under the “CurvGrid” and “CurvTrim” trademarks. 
   In keeping with one aspect of the present invention, one or more primary or tube carriers, generally designated  20 , is utilized to interconnect the main runners  10  and provide a unitized, rigid grid system. Each primary carrier  20  preferably extends substantially the full width of the suspended ceiling and is preferably spaced no more than about 48 inches from the adjacent primary carrier. The primary carrier  20  may be of any length that is practical given both manufacturing and shipping constraints, and typically may be as long as 16 feet in length. 
   The primary carrier  20  preferably has a circular cross-section, with an outside diameter of approximately 1.25 inches, although other cross-sectional shapes and sizes may be utilized without departing from the invention. The primary carrier has a notch or slot  22  for each of the main runners supported by the tube carrier  20 , the notch  22  being sized in width and depth to receive the bulb of the main runner. In a preferred embodiment, the tube carrier  20  is roll-formed from 0.028 inch thick steel with a lock seam  20   a . The notches  22  aid in the installation of the ceiling by maintaining on-center spacing of the main runners  10  without the use of cross tees. 
   If the width of the curved ceiling is greater than the length of a single primary carrier  20 , adjacent primary carriers can be staggered so that together they extend substantially the full width of the ceiling. More preferably, one or more primary carriers may be joined together end-to-end to obtain the desired length by using a splice connector  21 , as shown in  FIG. 3 . With reference to  FIGS. 3 and 4 , approximately half the length of the splice connector  21  is received in the interior of each of the two primary carriers joined thereby. The primary carriers and splice connector may be positively secured to one another by fasteners, such as screws  21   a . The primary carriers  20  may also include an inwardly-projecting embossment spaced from their ends that serve as a stop to prevent over insertion of the splice clip  21  into the primary carriers  20 . 
   The splice connector  21  may be made from electrical metallic tube (commonly referred to as “EMT”) having an outside diameter and cross-sectional shape that is complementary to the inside diameter and cross-sectional shape of the primary carrier  20 . The splice connector  21  has a slot  21   b  along its length to allow it to mate with a lock seam  20   a  in the tube carrier  20 , thus preventing rotation of the splice clip  21  and maintaining the angular alignment of the splice clip relative to the primary carriers  20 . 
   With reference to  FIGS. 5 and 6 , clips  24  with cut-outs  26  are provided that fit over the top of the primary carrier  20  to secure the main runners  10  to the primary carrier  20 . The cut-outs  26  are generally complementary in shape to the primary carrier and thus, in the illustrated embodiment, are generally an inverted U-shape. The clip  24  is provided with opposed faces  28 , the bottom edges  30  of which terminate in inwardly-pointing lips that are adapted to support the bottom surface of the bulb of the main runner. Alternatively, the clip  24  may be formed with inwardly-pointing tabs (not shown) for the same purpose. The clip  24  has aligned holes  34  in its opposed faces  28  for receiving screws  36  that draw together the lips or tabs on the clips so that they securely support the bulb of the main runner  10 . The clip  24  preferably includes stand offs  37  that are received on the shanks of the screws  36  and are sized in length to prevent over-tightening for the screws. 
   One advantage accruing to the present invention is that the primary carrier provides a cantilevered attachment point for the perimeter trim, allowing the hanger wire for suspending the grid to stand off from the end of the carrier tube, thus shielding the hanger wire from view. To this end, a perimeter clip  38  for securing the primary carrier  20  to a trim piece  14  is shown, best seen in  FIGS. 7 and 8 . The primary carrier perimeter clip  38  comprises three L-shaped segments  40 ,  42 ,  44 , joined together on one leg of the L, that are bendable into a generally U-shaped member. When bent, the corner  46  of one leg of each of the outer L-shaped segments is partially received in the upper of two opposed slots on the trim pieces, while the edge  48  of the corresponding leg of the middle L-shaped segment is received in the lower of the two opposed slots. The other leg of each L-shaped segment extends generally perpendicularly from the trim piece  14  to support the primary carrier  20 . Each of the two outer arms that support the primary carrier  20  includes an aperture  50  adapted to receive a screw or other fastener for positively securing the clip  38  to the primary carrier  20 . 
   With reference to  FIGS. 9 and 10 , a second perimeter clip  52  is shown for securing the main runners  10  to a perimeter trim piece. (Such clips may also be used to secure cross tees, if used, to a perimeter trim piece.) The main runner perimeter clip  52  is also generally L-shaped, with one leg of the L having opposed edges that are received in the opposed slots of the straight trim piece  14 . This leg preferably includes a tapped hole  54  for receiving a set screw  56  that may be tightened against the web of the trim piece  14  to lock the perimeter clip  52  thereto. Preferably, this leg has a curved edge  58  that permits the clip  52  to be positioned on the trim piece and then simply twisted to cause its edges to locate in the opposed slots in the trim piece. The other leg is adapted to lie along the web of the main runner  10 , and includes an ear  60  which can be folded through a slot in the main runner  12  to lock the main runner thereto. 
   Turning to  FIGS. 11 and 12 , a splice clip  62  is provided for joining lengths of perimeter trim  14  to each other. The splice clip  62  has two parts  64 ,  66 . The first part  64  has opposed edges  68  which are received in the opposed slots on the trim piece. The second piece  66  overlies the first piece  64  to clamp the lips that define the slots in the trim piece between the two pieces of the splice clip  62 . The second piece  66  has four corners  70  that are bent downwardly to engage the lips of the channels that receive the first piece  64 . The two pieces  64 ,  66  of the splice clip  62  are attached together by a pair of screws  72 . 
   The grid system of the present invention is suspended by hanger wires secured to the primary carriers, rather than to the main runners. This minimizes the number of hanger wires required to support the system. For smaller-sized ceilings, the curved grid system as described can be easily and accurately assembled on the floor of the space in which it is to be installed, and then raised as a unit in order to secure the hanger wires to the tube carriers. Otherwise, the primary carriers  20  are first hung, and the remaining components of the grid system then secured thereto. With reference to  FIGS. 1 ,  4  and  13 , a plurality of hanger clips  74  is provided that secure the hanger wire to the primary carriers  20 . The hanger clips  74  have a strap portion  76  that is partially covered with a resilient, rubber-like sleeve  78  that conforms to the shape of the surface of the tube carrier  20  contacted by it. The hanger clips  74  have a slightly oversized opening with respect to the diameter of the primary carrier in order to permit a minor amount of relative rotation between the hanger clip and the primary carrier. This ability to rotate with respect to each other allows a certain amount of “self centering” of the tube carrier with respect to the hanger wire, so that the hanger wire extends generally perpendicularly from the primary carrier. This subjects the hanger wire to less stress at the point at which it is secured to the hanger clip. 
   Thus, a suspended ceiling system particularly suited for a curved grid has been provided that facilitates accurate and quick assembly with enhanced structural rigidity. While the invention has been described in terms of a preferred embodiment, it is not intended to be limited to the same. Indeed, variations are contemplated that are within the ordinary skill in the art. For example, while the system has been described in connection with curved main runners, the primary carriers could also be used with a more conventional planar grid system. In addition, while cross tees are not required for structural reasons, they may still be utilized with the present invention for aesthetic reasons if, e.g., the lay-in panels have an edge reveal. Also, the primary carrier may have a cross-section other than generally circular without departing from the invention.