Abstract:
A suspended ceiling system comprising a plurality of spaced parallel main runners, a plurality of spaced parallel panel support bars intersecting and being fixed to the main runners at an oblique angle, a plurality of rhomboidal panels having angles equal to said oblique angle suspended from the bars, the panels having nominal width dimensions that are equal to or whole fractions of a distance between adjacent runners, the panels having opposed first edges extending perpendicularly to a direction in which a width of a panel is measured and opposed second parallel edges extending in a direction that is at said oblique angle relative to a direction that the first edges extend, the second panel edges underlying respective bars and having attached torsion springs received in slots formed in the bars.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to suspended ceilings and, in particular, to systems employing torsion spring mounted panels. 
     PRIOR ART 
     Torsion spring mounted ceiling panels have generally been limited to use in systems in which a supporting grid and the panels themselves are rectangular. This convention has limited the look of ceiling installations to rectangular patterns. Architects, interior designers, building tenants and owners want distinctive ceiling treatments. 
     SUMMARY OF THE INVENTION 
     The invention provides a suspended ceiling system that affords a distinctive, non-rectangular geometric look. The system includes a suspension grid and complementary torsion spring supported rhomboidal panels. The inventive system allows the panels to be of most any rhomboid shape, equivalent in size to conventional ceiling panels, as specified by a designer. In the disclosed system, the grid has main runners or tees in parallel relation, typically spaced on four foot or two foot centers. Panel support bars extend between adjacent tees at a predetermined oblique angle. The disclosed bars can have a channel-shape cross-section with a lower web having slots for receiving torsion springs and locating tabs on edges of the panels. Flanges of the bar upstanding from the web have notched ends configured to fit over a tee flange while the web underlies the tee flange. This construction allows the bars, when being installed, to be supported on and slid along the respective tees to a desired location. Bar ends on opposite sides of a tee can be aligned by a bridge plate assembled over the top of a tee and abutted against the bar flange ends. The bars are fixed on the tees by screws assembled through the bar web ends and the overlying tee flange areas. Slots on the bars for receiving the panel torsion springs and locating tabs of adjacent panels are offset or staggered in accordance with the invention to accurately locate the panel edges along straight sight lines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a somewhat schematic plan view of a portion of a chevron shaped ceiling construction employing the invention; 
         FIG. 2  is a plan view of a long right hand bar used in the grid of  FIG. 1 ; 
         FIG. 3  is a plan view of a short right hand bar used in the grid of  FIG. 1 ; 
         FIG. 4  is a cross-sectional view typical of the bars of  FIGS. 2 and 3 ; 
         FIG. 5  is a fragmentary plan view on an enlarged scale showing details of apertures for springs and locating tabs at a typical spring center of the long and short bars; 
         FIG. 6  is a perspective view of an end typical of the bars; 
         FIG. 7  is a perspective view of a bar splice plate; 
         FIG. 8  is a plan view of a large right hand panel; 
         FIG. 9  is a plan view of a small right hand panel; 
         FIG. 10  is a typical cross-sectional view of an edge of the panels of  FIGS. 8 and 9 ; 
         FIG. 11  is a fragmentary perspective view of a panel with a torsion spring clip with integral locating tabs and assembled with a torsion spring; 
         FIG. 12  is a perspective view of two bar ends intersecting a main tee from opposite sides and aligned with the splice plate; and 
         FIG. 13  is a perspective fragmentary view of two adjacent panels and their torsion springs at a spring center of a common bar. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  illustrates a suspended ceiling  10  employing rhomboidal panels  11   a ,  11   b  arranged in a chevron pattern. As shown, the panels  11   a ,  11   b  can be of different size and can be of right or left hand shape. The panels  11  are suspended on a grid of parallel tees or runners  12  and parallel bars  13   a ,  13   b  obliquely intersecting the tees  12 . Where the panels  11  form of a chevron pattern, the bars, like the panels  11 , are provided in symmetrical right and left hand versions. 
     The tees  12  can be conventional suspended ceiling main tees or runners well known in the industry. The bars  13  are unique and their geometry will depend on the acute angle selected for the rhomboid shape of the panels  11 . In the illustrated case, the acute angle has been selected to be 52 degrees. 
     In the disclosed arrangement, the elongated bars  15  are provided in two different lengths. The shorter bar being designated  13   a  and the longer bar being designated  13   b . The illustrated bars  13  are formed as sheet metal channels that are installed hollow side up.  FIG. 4  illustrates a typical cross-section of a bar  13  shown with a horizontal web  14  and upstanding flanges  15  extending vertically from longitudinal margins of the web  14 . 
       FIGS. 2 and 3  illustrate right hand versions of the bars  13 . The longer bars  13   b  have four torsion spring locations  17  and the short bars  13   a  have two torsion spring locations  17 . Where the main tees  12  have a nominal center-to-center spacing of four foot, the longer bars  13   b  have a length of about 60.4 inches so that at a 52 degree angle relative to the tees, they will span between two adjacent tees. Similarly, the shorter bars  13   a  with nominal lengths of about 30.3 inches and 52 degree orientations span between tees  12  on two foot centers. Left hand versions of the bars  13  are symmetrical and have the same dimensions. 
     A typical end construction of a bar  13  is illustrated in  FIG. 6 . Material is removed at the juncture of the web  14  and flanges  15  to form a clearance slot  21  at the end of each flange and to form a cantilevered tongue area  22 . The clearance slot  21  is widened at an inner part for clearance of a conventional hem  23  ( FIG. 12 ) on a flange  24  of a tee  12 . Holes  26 ,  27  are punched in the flanges  15  and tongue  22  for fixing a bar  13  in an installed position as described below. 
     Torsion springs  31  ( FIG. 11 ) and associated locating tabs  32  of a ceiling panel  11  are received in respective apertures or slots  56 ,  57  ( FIG. 5 ) punched in the bar web  14  at spring locations  17  indicated in  FIGS. 2 and 3 . 
     A bar  13  is installed on a pair of adjacent tees  12  by locating flange end portions  37  over the tee flange  24  ( FIG. 12 ). The bar flange portions  37  can support the bars  13  on the tees  12  and allow the bars  13  to slide on the tee flanges  24  until they are in a desired position. 
     As depicted in  FIG. 12 , the bar  13  on opposite sides of a tee  12  can be mutually aligned with a bridging splice plate  38  ( FIG. 7 ). The plate  38  is preferably a sheet metal stamping with a central slot  41  open at a bottom edge and a stiffening flange  42  at a top. The slot  41  provides clearance for an upper reinforcing bulb  43  of a tee  12 . The plate  38  has preformed holes  44  for screws used to attach the plate to the flanges  15  of the bars  13  being aligned. The plate  38  is abutted and fixed with screws against flanges  15  of the pair of bars  13  being aligned. A bar  13 , once properly located on a tee  12  is fixed in position by driving screws through holes  27  in the bar tongue  22  into the overlying flange  24  of the supporting tee  12 . 
       FIGS. 8 and 9  illustrate two examples of right hand rhomboid panels, both being nominally 24 inches wide. The smaller panel  12   a  measures 15.743 inches between two sides that extend obliquely to the 24 inch width and the large panel  12   b  measuring nominally 42 inches on two sides extending perpendicularly to the 24 inch width. For a chevron ceiling design such as shown in  FIG. 1 , both right and left hand symmetrical panels  11  and bars  13  are utilized. 
     The panels  11  are typically made of sheet metal such as aluminum. The panels are bent up at their edges to provide sidewalls or sides  46  that stiffen the panel. A panel  11 , inward of its sides  46  is ordinarily flat and made be perforated to afford sound absorption characteristics. All of the panel sides  46  are preferably over-bent to an angle, with reference to the panel center, of 88 degrees, for example, as shown in  FIG. 10 . 
     Sides of the panels  11  that extend between the sides  46  associated with the nominal width of the panel are fitted on their interiors with clips  51 , two per side ( FIG. 11 ). The clips  51 , which are riveted or otherwise fastened to a panel side  46 , each carry a torsion spring  31  and provide a pair of integral alignment tabs  32 . The clips  51  and torsion springs  32 , as well as their functions, are known, for example, from U.S. Pat. No. 9,228,347. 
     The panels  11  are arranged beneath the grid formed by the tees  12  and bars  13  so that the torsion springs are aligned with the torsion spring locations  17  of the bars  13 . Referring to the plan view of  FIG. 5 , each spring location  17  of a bar  13  has apertures  56 ,  57 , respectively, to receive the torsion spring and the alignment or locating tab pair of each clip  51  of two side-by-side panels  11  underlying the bar. The square apertures  57  are configured to accurately locate the tabs  32 , and therefore an associated panel  11 , longitudinally and laterally on the respective bar  13 . The elongated apertures or slots  56  receive the arms of the torsion springs  31  allowing the springs to draw a panel side up against the bar  13  and allow the panel to be manually pulled down, against the force of the spring, away from the bar for access to the plenum above the ceiling  10 . 
     Close inspection of  FIG. 5  reveals that a set of the apertures  56 ,  57  for one panel, i.e. a set to one side of a longitudinal center line  60  of the web  14  of a bar  13  is longitudinally offset from the other set. It has been discovered that this offset adjustment allows adjacent panels to accurately align at the edges of their lower faces. 
     Where the panel acute angle is, for example, 52 degrees and the lateral spacing between the tab receiving apertures  57 , i.e. between apertures on opposed sides of a longitudinal center of the bar web, is 0.688 inches, the longitudinal offset can be 0.146 inch. This offset is evenly split longitudinally between each aperture set from a specified center of the spring location  17  on the longitudinal center line  60  of the bar web  14 . The offset is in a direction where a line drawn between mid-points of adjacent apertures  57  for tabs of adjacent panels tends to be aligned with the direction of those panel edges without springs. 
     The pattern of panels of  FIG. 1  can be extended laterally and/or longitudinally or without any such extension can be repeated laterally. 
     Different ceiling aesthetics can be achieved with variations in the position of the tees  12  from a common single horizontal plane. For example, tees  12  on opposite sides of an intermediate tee  12  can be at a lower or a higher horizontal plane giving the ceiling a concave or a convex appearance from below. In such instances, the 88 degree over-bend of the panel sides or sidewalls  46  of the panels  11  avoid unsightly gaps at the panel edges. Still further, the tees  12  can be arranged to rise and fall at prescribed nodes where the tees are partially cut while leaving their flanges  24  intact but otherwise acting as a hinge. In these situations, the bars  13  are arranged to follow the local elevations of the tees  12  to which they are fixed. 
     It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.