Abstract:
An acoustical panel assembly for a suspended ceiling comprising a rigid frame, sound absorbing material, sound transmission attenuation material and a face fabric. The frame is an assembly of extruded members secured together in a polygonal pattern such as a square or a rectangle. The fabric is secured to the frame by gripping elements integral with the frame. Marginal portions of the fabric are captured and hidden in receiving chambers formed by the frame members.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to improvements in suspended ceiling panels and, more specifically, to fabric covered panels for suspended ceilings. 
     PRIOR ART 
     Suspended grid ceiling systems are in widespread use because of their functionality in allowing access to the plenum for service, alternation and/or addition to wiring, air conditioning, heating, plumbing and other hardware typically found in a building. Ceiling panels that lay in the suspended grid come in a variety of materials and finishes. Most commonly, the panels are rigid boards made of various materials that often have their visible faces perforated or otherwise textured to obtain a level of sound absorption. U.S. Pat. No. 4,026,081 shows an example of a fabric covered acoustical panel with a rigid perimeter frame for use with a suspension ceiling grid. The product disclosed in this patent requires a vinyl rope to retain the fabric and the attendant complications of handling and installing the rope. Additionally, this patented product may be difficult to install and especially to remove. This is of particular consequence where the person attempting to install or remove the panel is unfamiliar with the motions which apparently must be performed to place or remove the patented panel. 
     SUMMARY OF THE INVENTION 
     The invention provides an improved fabric covered acoustical panel assembly for suspended ceiling structures that uses inexpensive parts, is readily assembled and is easy to install and remove. The disclosed panel assembly has a rigid polygonal perimeter frame that serves to hold the fabric, a sound absorbing material and a sound transmission attenuating material in assembled relation and precisely engages supporting flanges of the tees of a suspension grid. The frame is preferably an extrusion of suitable thermoplastic such as polyvinylchloride. 
     As disclosed, the frame has integral gripping elements that frictionally engage the margin of the fabric facing. The gripping elements allow the fabric to be simply and quickly installed on the frame by tucking its margins into the reach of the gripping elements. The frame includes a cavity for receiving any excess marginal material and thereby neatly controlling its location regardless of limited extra material or imperfect positioning of the fabric. Thus, the edge of the fabric does not “read through” the visible part of the fabric. The gripping elements of the frame are situated so that the fabric margins can be tucked into their control from operations conducted on the front or visible face of the panel so that the fabric condition and position can be continuously observed and corrected for proper positioning by the person installing the fabric on the frame. Additionally, the frame includes retaining rib elements for holding the sound absorbing material in place. Still further, the frame includes a support area for receiving and locating the sound transmission attenuating material. 
     The disclosed panel construction is suitable for factory mass production, limited production in a small shop or custom manufacture at the site where the panels are to be installed. The frame is assembled by connecting its sides together at corners with an angle bracket that is simply pushed longitudinally into the sides and is retained in place by a strong friction fit. The panel assembly can be readily recovered with fabric when damaged, outdated, or other conditions require a change. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary perspective view of a suspended ceiling incorporating ceiling panels constructed in accordance with the invention; 
     FIG. 2 is a fragmentary cross-sectional view of a pair of adjacent panels constructed in accordance with a first embodiment of the invention and a supporting grid tee; 
     FIG. 3 is a fragmentary plan view of the corner of a perimeter frame of the panel according to the first embodiment; and 
     FIG. 4 is a fragmentary cross-sectional view of a pair of adjacent panels constructed in accordance with a second embodiment of the invention and a supporting grid tee. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and in particular to FIG. 1, there is illustrated a suspended ceiling structure  10  comprising a rectangular grid  11 , and a plurality of panels  12  supported on the grid. The grid  11 , according to conventional practice, is made of runners  13  having the configuration of an inverted tee. The runners  13  are typically suspended from an overhead structure with wires that are looped through holes in a stem or vertical part  14  of the grid runner  13 . The runners  13  are made of steel but can be of other suitable material. The runners  13  have oppositely extending horizontal flanges  16  that serve to support the panels  12  in a manner to be described. Commonly, the tees or runners  13  are provided with connections at their ends to enable them to be joined with intersecting tees and/or with ends of other tees. Typically, the tees are arranged in a rectangular array that has openings for the panels  12  that nominally measure 2′×2′ or 2′×4′. 
     The panels  12  are assemblies of a rigid perimeter frame  17 , fabric or fabric sheet  18 , sound absorbing material  19  and sound transmission attenuating material  20 . The fabric sheet  18  forms the visible face or face side of the panel when it is installed in the ceiling grid. The illustrated frame  17  is an assembly of four side members  22  and four corner connectors  56 . The four side members have identical or substantially similar cross-sections shown as typical in FIG.  2 . The side members  22  are preferably formed as extrusions of a suitable thermoplastic material such as polyvinylchloride with flame resistant properties satisfying suitable standards such as ASTM-E84 and are Class A-rated for flame spread. The cross-section of a side member  22 , which is uniform along its length, is somewhat complex to enable it to serve multiple functions. The cross-section includes a lower generally horizontally extending flange  26  which has an extension or flange  35  having an upwardly curved or angled lower surface  24  which prevents the plastic frame member “reading through” the stretched fabric  18 . Extending generally vertically upwardly from the flange  26  is a web  27  having a plurality of barbs  28  projecting towards the center of the panel  12 . The barbs  28  are optional and have angled surfaces  29  on their upper faces and less inclined almost horizontal surfaces  30  on their lower sides. A main bridge or flange  31  at the top of the web  27  extends primarily outwardly away from the center of the panel  12 . Towards the center of the panel  12 , the bridge  31  provides a projection  32  that has a steeply inclined camming surface  33  and a generally horizontal retaining face  34 . 
     A pair of spaced parallel flanges  36  extend vertically from the main bridge  31 . Oppositely facing ribs  37  existing on each flange  36  have lower surfaces  38  that cooperate with surfaces  39  of the flanges  36  to form the sides of a longitudinally extending rectangular channel  41  of a C section. Depending from the main bridge or flange  31  and lying in the same plane as the upstanding flange  36  is a generally vertical web  42 . A generally horizontal flange  43  projects from a lower end of the web  42  in a direction away from the center of the panel  12 . As shown, a lower surface  44  of the flange  43  is inclined upwardly in a direction away from the center of the panel  12  to bias the vertical web  42  towards the center of the panel  12  when the weight of the panel is borne by this surface on the flange  16 . Alternatively the lower surface  44  may be horizontal. Adjacent its lower end, the web  42  has a series of longitudinally extending small gripping ribs  45  on a surface  46  facing the center of the panel  12 . A generally vertical leg  47  extends upwardly from an outer edge of the flange  26 . The flange  26  and leg  47  intersect to form a rounded corner  48 . The leg  47  has an inwardly bent area  49  that provides a longitudinally extending recess  51  that is roughly centered, in a vertical sense, on a plane tangent to the inner end of the flange surface  44 . Adjacent its upper edge, the leg  47  has a series of small gripping ribs  52  that oppose the ribs  45  on the depending web  42 . Ideally, in a free state and before assembly of the fabric  18  as described below, the leg  47  is configured so that its ribs  52  resiliently contact the ribs  45  of the depending web  42 . The depending web  42 , main flange  31 , barbed web  27 , lower flange  26  and leg  47  cooperate to form a closed chamber  54 . 
     The side members  22  are mitered at the corners of the frame  17  as shown in FIG.  3 . The members  22  are joined at the corners by a corner connector or right angle piece or angle bracket  56 . The bracket  56  can be made of suitable plastic material such as polyvinylchloride. The bracket  56  is economically made by cutting short sections of a long piece of angle stock. A leg  57  of each angle bracket  56  is assembled in the channel  41  of the two frame side members  22  forming a corner. The cross-section of the bracket legs  57  is preferably proportioned to provide a tight force fit into the channel  41  to frictionally lock the members  22  together and thereby assure that the frame can be freely handled without the risk of it inadvertently coming apart. 
     The distance between an upper face  58  of the lower flange  26  and an underside  34  of the projection  32  is made to receive the thickness of the sound absorbing material  19 . Preferably the sound absorbing material is commercially available rigid fiberglass board of 1″ thickness and a density of preferably 6 lbs. per cubic foot and less preferably as low as 3 lbs. and as high as 20 lbs. density. The planar dimensions of the sound absorbing material or board are made to closely fit within the perimeter frame  17  so as to have its edges gripped and held in position by the barbs  28 . The camming surface  33  facilitates inserting the sound absorbing material into the frame  17 . 
     A top face  61  of the main flange  31  and an inner face  62  of the inner flange  36  form a perimeter pocket area for reception of the sound transmission attenuating material  20 . This material is preferably gypsum board or drywall but can be other suitable fire resistant materials such as sheet rock, plywood, flake board, particle board or the like, rated to meet fire code requirements for combustibility and smoke and flame spread. The material  20  is cut to a planar size to loosely fit within and be contained by the boundary formed by the flange surface  62 . The board can have a thickness of, for example, ⅜″. 
     With the frame  17  assembled and the sound absorbing board material  19  in the frame, the frame can be inverted onto a suitable support such as a work table for installation of the face material or fabric  18 . The fabric is a suitable material such as a quality weight upholstery fabric that, ideally, is hydrophobic or with as little hydrophilicity as possible so as to avoid moisture absorption and potential sagging. Preferred fabric materials are panel fabrics, such as panel fabrics from Guilford of Maine. Suitable fabric materials include polyester as a preferred material and, less preferably, polyolefin materials, vinyl-coated fabric, or acrylic fabric. The fabric  18 , like the other materials of the panel, are flame retardant and preferably satisfy ASTM standard E84. The fabric  18  is cut oversize of the finished fabric covered area. Marginal areas of the fabric are tucked in the crevice between the web  42  and leg  47  with a flat tool like a putty knife. This can be done most efficiently by working the fabric material into the crevice at one side member  22  first and then into the crevice at the opposite side. This procedure is then performed at the remaining two sides. The cavity or chamber  54  is relatively large so it readily accommodates excess marginal material of the fabric  18 . Proper positioning and tensioning of the fabric  18  is relatively easy because its alignment and local stretch can be viewed as it is being tucked into the frame crevices. The fabric  18  is stretched over the frame to the desired degree by appropriate manipulation of the flat installation tool. The fabric  18  is reliably held in place by the gripping ribs  45 ,  52  to a degree sufficient to maintain the fabric tensioned during normal surface life of the fabric  18 . Other gripping elements known in the art may be used, such as opposing teeth or projections or interlocking surfaces or other surfaces which lockingly or frictionally hold the fabric. Any loosening of the fabric after a panel  12  has been installed can be accomplished in the same manner as the fabric was originally tensioned. It is also noteworthy that the ribs  45 ,  52  will release the fabric when a strong pulling force is applied such as in the case where it is desired to replace the fabric. 
     After the fabric has been installed, the subassembly of the frame  17 , fabric  18  and sound absorbing material  19  can be turned so that the fabric is facing downward and the sound transmission attenuating material  20  can be positioned on the frame. 
     With placement of the sound transmission attenuating board material  20  in the pocket bounded by the flanges  36 , the assembly of the panel  12  is complete. The panel is installed on the grid  11  in a generally conventional lay-in manner. The hollow area of the recess  51  can receive a portion of the grid tee flange  16  to permit the panels  12  to be installed on a grid even where the grid is slightly out of proper position or where the panel is slightly oversize for the opening left by the grid. It will be understood that the panel assembly  12  can be manufactured in a factory, small shop, or on site where it is to be used. The frame members  22  are saw cut from long stock lengths. The disclosed panel assembly  12  does not require any fasteners or adhesives apart from the right angle bracket  56 . If desired, the area adjacent the corner  48  can be covered with double-sided tape or otherwise provided with pressure-sensitive adhesive to facilitate placement and stretching of the fabric  18  on the frame  17 . 
     Various modifications of the panel assembly are contemplated. While the preferred arrangement is of the tegular type where the face of the panel assembly represented by the fabric  18  lies in a plane below the plane of the grid flanges  16 , as shown in FIG. 2, a panel can be configured to have its face lie at or above the plane of the grid tee flanges. The edge detail, defined by the corner  48  can be greater or less in radius than that shown, can be beveled, and can even be square. Where desired, the gypsum board  20  or its equivalent can be omitted or can be cut out to mount an audio speaker. Similarly, the sound absorbing material  19  can be omitted to allow the speaker to be hidden behind the fabric and to operate without interference of such material. As suggested, the panel can be constructed to fit either 2′×2′ or 2′×4′ standard ceiling grid modules or can be made into other suitable polygonal shapes such as triangles, hexagons and octagons. The frame can be dyed, painted, stained or otherwise colored to match the color of the fabric. If desired, the sound absorbing board  19  can be replaced by drywall, foil-backed fiberglass, non-rigid fiberglass batts or like material. 
     FIG. 4 illustrates a second embodiment of a ceiling panel assembly  70 . The panel assembly  70  includes a frame constructed of side members  71 , sound absorbing material  19 , sound transmission attenuating material  20  and a fabric face  18 . In this embodiment, like numerals are used to identify like materials common with the embodiment of FIGS. 2 and 3. The frame side members  71  have identical cross-sections as shown in FIG.  4 . The frame side member cross-section includes a generally vertical wall  72  that at its lower end is curved to transition from a vertical surface  73  to a horizontal surface  74 . An inner face  76  of the wall includes a horizontally projecting barb  77 . The outer vertical surface or face  73  has a series of gripping ribs  78  at its mid-section. A generally C-shaped panel  79  formed by flanges  81 ,  82  and a web  83  is joined to the vertical wall  72  by a web  84 . An inverted J-shaped channel  86  extends upwardly from the web  84  horizontally, and then downwardly alongside an upper portion of the wall  72 . An inside surface of a lower part  88  of the J-channel has ribs  89 . At its lower end, the J-channel  86  has a horizontally extending flange  91  that engages the flange  16  of a supporting tee  13 . An interior of the J-channel  86  forms a chamber  92 . 
     Opposing areas of the J-channel  86  and the web  83  include ribs  93  to form the boundary of a rectangular open sided channel  94 . Like the embodiment of FIGS. 2 and 3, a rectangular frame is constructed with appropriate lengths of the side members  71  having the cross-section illustrated in FIG.  4 . The lengths are suitably mitered similar to the showing in FIG.  3 . The frame is assembled around the rigid rectangular board of sound absorbing material  19  and a rectangular piece of drywall or other suitable sound transmission attenuating material  20 . The projection or barb  77  digs into the sound absorbing material  19  to retain it in position. An angle bracket like the bracket  56  shown in FIG. 3 can be used in the open-faced channel  94  under the ribs  93  to lock the frame members  71  together. 
     With the frame members  71  assembled together around the sound absorbing material  19  and sound transmission attenuating material  20 , the fabric  18  can be installed. This is accomplished in a manner like that described in connection with the embodiment of FIGS. 2 and 3. The margins of the fabric  18  are tucked between the wall  72  and leg or lower part  88  of the J-channel  86 . The J-channel leg  88  resiliently grips the fabric material  18  with its ribs  89  holding it against the mutually gripping ribs  78  on the wall  72 . 
     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.