JP2023065452A - Earthquake-resistant suspended ceiling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspended or "lowered" ceiling system based on the use of a standard inverted T-bar grating.

SOLUTION: A ceiling panel that captures a T-bar in a style that prevents the panel from wobbling and vibrating when assembled in place consists of two pieces. A suspended ceiling assembled with the panels of the present invention would withstand seismic loads without experiencing panel dropout, and the ceiling would remain in an original condition as long as the T-bars remain suspended from the structural ceiling above. The panels of the present invention can support light fixtures in the preferred embodiment, and the necessary wiring can be installed and concealed below the T-bar rather than within a plenum.

SELECTED DRAWING: Figure 9

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to suspended ceiling systems based on the use of inverted "T-bar" grids, and more particularly to ceiling panels that cannot rattle from the suspended grid when installed.

Most suspended or "descent" ceiling configurations in use today employ so-called T-bar rails, having an inverted "T" cross-section, arranged in a rectilinear grid and suspended from the structural ceiling by tether wires or metal straps. be done. This system is essentially less modern and is described in US Pat. No. 2,710,679 (issued June 14, 1955 to Bibb et al.). In general, rectangular ceiling tiles, either ventilated acoustic tiles or decorative panels, are slanted and inserted between the T-bars, leveled and dropped into the grid, the tiles being inverted "T ” on the horizontal flange. In the United States, suspension grid cell sizes are generally either 24 inches by 24 inches or 24 inches by 48 inches, while in Europe and elsewhere, suspension grid cell sizes are 600 mm x 600 mm or 600 mm x 600 mm. It is 600mm x 1200mm. The ceiling tiles are actually about 1/4 inch (6 mm) below their nominal size (ie cell size) to facilitate easy installation between the vertical stems of the T-bar.

The popularity of this configuration stems from its ease of installation and low cost, and from the fact that the individual tiles are easily pushed up and off the rails whenever access to the space above the ceiling is required. and can be returned to its original position without damage. Tiles with any desired finish and appearance can be manufactured to fit standard T-bar grids, giving decorators and architects a wide range of design options. Light fixtures and air diffusers and grilles sized the same as the tiles can be lowered into the grid whenever desired. Standard sized tiles and fixtures are commercially available from a wide variety of sources.

One disadvantage of this system is that during an earthquake, the tiles and fixtures will bounce up and down against the T-bar flanges and in turn not be mechanically connected or attached to the T-bars, resulting in , or can be dropped onto building occupants. As the tiles fall from their location, the suspended grid tends to bend and cause more movement and distortion, causing more tiles to fall, often resulting in complete ceiling failure.

In earthquake-prone areas, seismic building codes often require oblique (diagonal) tie wires installed to limit lateral movement and distortion of the lattice of the grid during an earthquake. Vertical struts are sometimes installed as well to limit the vertical movement of the grid. While such precautions make the grid stiffer and ensure that it moves with (and does not move with) the structure, it reduces the labor and cost of installation. increasing, the precautions do not totally prevent individual tiles and fixtures from leaving the T-bar. Securing the tiles to the T-bar takes a lot of labor, for example by installing retaining clips, and prevents easy access to the space above the ceiling. Easily accessed clips tend to be visible and can detract from the aesthetics of the ceiling design. Safety mechanisms that "catch" falling tiles (e.g., U.S. Pat. No. 5,253,463, issued Oct. 19, 1993 to Witmyer) still allow the tiles to separate from the T-bar. , the grid can still suffer from a consequent loss of stiffness.

Tiles having slots or kerfs along the sides into which T-bar horizontal flanges fit are known. Because the kerf tiles are intended to partially or completely hide the grid from view from below and are locked to the grid, they also provide improved seismic capacity. Tiles with four kerf sides are rarely employed. This is because the tiles must be slid into place when the T-bar grid is assembled, and the tiles present installation-related problems when the assembly process reaches the walls. A kerf designed to be installed in an existing grid, featuring some combination of splits in the flange and/or upper edges of the kerf that allow the tiles to slide into place. There are grooved tiles. Tiles are known that feature a small upper edge along two adjacent kerfs that take advantage of the 1/4 inch clearance between the tile and the grate to allow installation, but such tiles Doesn't lock to grid properly. Kerf tiles with gaskets that snap into place above and below the horizontal surface of the T-bar are known (e.g., U.S. Pat. See U.S. Pat. No. 5,507,125, issued Apr. 16, 2004 to McClure). Removal of kerf tiles without damage to access the space above the ceiling can be difficult or impossible, especially when the method of installation is not apparent to the person attempting removal. .

Separate frames intended to obscure the T-bar are known (e.g., U.S. Pat. No. 4,4980,957 to Bumpus et al., Jan. 1, 1985), but are for aesthetic purposes only. These frames that do the job clip the T-bars and do not fasten the ceiling tiles. There is a need for a suspended ceiling system that remains easy to install and maintain, yet does not drop the tiles in the event of an earthquake. Similar needs exist in mobile environments such as military and passenger ships, where ceiling structures are sometimes subjected to unusual forces and movements.

A feature of the suspended ceiling between the suspended tiles and the structural ceiling above is the air gap or plenum. When piping for both forced air supply and forced air return is installed, the air gap is "dead" space, ie filled with non-circulating air. In the absence of a return air duct, the plenum is typically provided with an exit duct and the space above the tiles is an "active" plenum filled with circulating air. Electrical wiring installed in an active plenum does not contain toxic fumes and fumes from the combustion of insulation and resins when toxic fumes and fumes would be in the dead void, but the building's air circulation system. may represent a fire hazard because it passes directly within Another hazard is that if combustible material is present, a fire in the plenum space can spread rapidly before it is detected.

When the air gap above the falling ceiling is used as an active plenum, building codes and/or local fire codes require that low voltage cables and wiring be installed inside metal conduit, or otherwise installed on their own. Require either low smoke/low toxicity wire insulation that does not support combustion to be provided. Twisted pair and coaxial cables for telephone and data network services are the most common forms of wiring found above the ceilings of commercial buildings. A special plenum (or plenum rated) cable is called a Low Smoke Zero Halogen (LSZH or LS0H) cable. Plenum rated cables are typically insulated and covered with fluorocarbon polymers, which are significantly more expensive than equivalent non-plenum rated wiring, which typically has less expensive polyethylene insulation and PVC jacketing.

High voltage electrical equipment and wiring (generally >50 volts) above the ceiling are required to be enclosed within metal conduits or raceways and need to be physically separated from low voltage wiring. Devices such as lighting fixtures and fixtures need to be enclosed in metal boxes. Electrical outlets can be inside the plenum space (if enclosed inside an electrical box), but the sockets themselves must be located outside the descending ceiling, so pluggable connections in fixtures is impractical. The overall result is that all fixtures and devices installed in the ceiling must be hardwired using metal conduits and junction boxes.

By meeting these configurations and fire codes, the conduits and boxes represent additional capital costs, substantially increasing the time and cost of installation and requiring a significant amount of skilled labor to install. do. In particular, adding high voltage wiring to a pre-installed system becomes difficult and expensive. There is a need for a suspended ceiling that can be safely wired without incurring the added expense of conduit, junction boxes, and plenum rated wiring, as well as allowing pluggable connections for appliances.

The present invention provides a ceiling panel comprising an upper frame and a reversibly attached lower frame. The upper frame is conventionally sized and configured to be mounted on a suspended T-bar grid. Once the upper frame is installed at the T-bar horizontal plane, the lower frame is mechanically locked to the upper frame to complete the installation. The lower frame is sized to at least partially cover the T-bar horizontal plane so that the two frames are functionally equivalent to a kerf tile when locked together. In ceilings constructed from these panels, the T-bar flanges are trapped between the frames and cannot separate from the panels when the ceiling swings or vibrates.

When two ceiling panels of the present invention are installed in adjacent cells of a T-bar lattice, the sides of the panels together define at least a channel large enough to enclose and capture the T-bar horizontal flanges. In a preferred embodiment, this channel comprises additional space below the T-bar. In an alternate embodiment, a second channel is defined. This additional space (or secondary channel) below and outside the plenum space serves as a utility channel that can support non-plenum rated wiring, cables, and fixtures. The channels between adjacent panels of the present invention align with the channels between adjacent panels to create extended utilization channels that extend the full length and width of the ceiling.

The present invention comprises a suspension grid of inverted T-bars, an upper frame that fits between the vertical stems and rests on the horizontal flanges of the T-bar grid, and a lower frame that is reversibly attached to the upper frame. Providing a suspended ceiling, the adjacent lower frame, together with the adjacent upper frame to which the adjacent lower frame is attached, defines a channel that partially or fully encloses the horizontal flange of the T-bar on which the upper frame rests. .

The present invention also provides a method of constructing a suspended ceiling, comprising the steps of suspending a reciprocal lattice of T-bars from an existing ceiling; installing between the vertical stems; and reversibly attaching the lower frame to the upper frame, the adjacent lower frame together with the adjacent upper frame to which the adjacent lower frame is attached. A channel is defined that partially or fully surrounds the horizontal flange of the resting T-bar.

Fig. 2 shows a top view of an example upper frame of the present invention; Fig. 2 shows a side view of an example upper frame of the present invention; 1 shows a cross-section of an example upper frame of the present invention; FIG. 11 shows a side view of an alternative embodiment of the upper frame of the present invention; Fig. 2 shows a top view of an example lower frame of the present invention; FIG. 2 shows a side view of an example lower frame of the present invention; 1 shows a cross-section of an example of a lower frame of the present invention; Fig. 3 shows different cross-sections of an example of a lower frame of the present invention; FIG. 4 is a perspective view showing the upper and lower frames of the present invention positioned on a T-bar grid; FIG. 11 is a perspective view showing a connecting set of upper and lower frames of the present invention on a T-bar grating; Fig. 2 is a perspective view showing a set of upper and lower frames of the present invention assembled on a T-bar lattice to form the ceiling panel of the present invention; Figure 11 is a perspective view of Figure 10 with the T-bar grating removed for clarity; Figure 2 shows a cross-section of a ceiling panel of the invention installed on and supported by a T-bar grating;

The present invention provides a ceiling panel for installation within a grid of suspended T-bars. The panel of the present invention comprises: an upper frame that fits between vertical surfaces and is sized to rest on the horizontal planes of a grid of T-bars; a lower frame reversibly attachable to the upper frame. The present invention, when the lower frame is attached to the upper frame, forms with the upper frame a channel that at least partially encloses the horizontal surface of the T-bar on which the upper frame rests. Therefore, when the horizontal surfaces on both sides of the T-bar are enclosed, the horizontal surfaces cannot free the channel when the panels are set in motion by a seismic event. The panel itself cannot be separated from the T-bar and will remain suspended as long as the T-bar grid itself remains suspended.

Various known art means of reversibly attaching the upper and lower frames can be employed, such as, for example, electromagnetic coupling, hook and loop fabric strips or patches, spring-loaded clips and snaps, and screws. Generally, the preferred means of attachment is immune to removal and removal subjected to the forces applied during an earthquake, but whenever a panel needs to be removed for inspection, maintenance, or modification of the ceiling or plenum, a worker It is a mechanical means that is easily reversed by Such attachments are referred to herein as "locked" or "locking" attachments. In a particularly preferred embodiment, as shown in the drawings of the invention, the ceiling panel of the invention has a lower frame attached to the upper frame by spring wire retainer clips, the clips being attached to one frame and the other. It fits into a slot in the frame of the The frames can only be separated when the wire clips are manually released. Easy-to-remove (eg, half-turn or quarter-turn) screws are another preferred means of reversible attachment. Captive screws may be particularly preferred.

In other preferred embodiments, the ceiling panels of the present invention may comprise lighting fixtures or lighting elements and associated hardware such as mounting brackets, heat sinks and diffusers. The lighting elements are preferably LED lighting elements affixed to one of the frames. The wiring for the LED elements can optionally be affixed to either of the frames and/or the wiring can extend between the frames. Electrical components are preferably located below the plane defined by the T-bar horizontal plane, allowing inexpensive non-plenum rated components to be safely installed.

In a preferred embodiment, the panels define a space between each other below the T-bar horizontal plane that acts as a utilization channel. For example, non-plenum rated wiring and cables, such as telephone, Ethernet, and coaxial cables, can be safely installed in the utilization channel beside the outside of the plenum. Other devices that can be installed along with the device wiring include wireless routers and repeaters, smoke detectors, fire alarms, security cameras, and the like.

The upper and lower frames may be manufactured from any material commonly employed in the manufacture of ceiling tiles and panels. Preferred materials are fiberglass composites and rigid polymer foams, which can be formed in a mold and then further shaped by machining if desired. Rigid closed-cell polyurethane foams are particularly preferred. Polyurethane foams are generally produced by reacting a di- or polyisocyanate with an isocyanate-reactive diol or polyol, present among one or more blowing agents, catalysts, surfactants, and other additives.

In general, any two component "A/B" polyurethane foam system that yields rigid foams can be employed and there are many suitable systems commercially available. Preferably, the rigid foam is a closed cell foam having a density of 2-8 lbs/cubic foot. As an example, a nonflammable two-component "A/B" injectable urethane foam precursor was formulated according to U.S. Pat. No. 7,141,613 (issued to Albach et al. can be Preferred isocyanate precursors include 4,4' diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, and mixtures thereof. Preferred polyol components include polyalkylene ether polyols and alkoxylated and non-alkoxylated Mannich polyols. Any polyurethane compatible flame retardant known in the art may be employed to impart fire retardant properties, such as, for example, tris(l-chloro-2-propyl) phosphate. Water is preferred as the blowing agent, but known blowing agents such as hydrocarbons, hydrofluorocarbons, or alkylformates can be supplemented. Rigid "architectural" polyurethane foams that meet or exceed building construction and fire codes are well known to those skilled in the art and would be particularly preferred in the present invention.

Referring to the drawings, FIGS. 1, 2 and 3 respectively show a top view, a side view and a cross-section of an exemplary upper frame 1. FIG. For clarity in the drawings, the embodiment shown in FIGS. 1-3 has an open upper frame, but when mounted on a T-bar flange as shown in the alternate embodiment of FIG. It can be closed with any kind of decorative panel 2 so as to form a coffered ceiling. The decorative panel may be co-formed and integrated with the upper frame, or the decorative panel may be formed separately from any material known in the art suitable for use in the construction of suspended ceilings, without limitation No, but may be attached to the upper frame by conventional means including adhesives, staples, screws, clips, and the like. Acoustic tiles, or metal or resin sheets that are molded or engraved to provide aesthetic appeal are specifically contemplated. Decorative panel 2 may be attached to conventional lighting or ventilation fixtures, as is known in the art. Acoustic and/or thermal insulation (not shown) may be attached to the upper surface of the decorative panel. In the embodiment shown, adapted for use with wire clips to attach the lower frame as further disclosed below, L-shaped slots 3 are formed in the upper frame near each corner, Or cut through the upper frame. Optional cut-outs 6a are shown and these cut-outs are described below in connection with FIG.

5, 6, 7 and 8 show a top view, a side view and two cross-sections, respectively, of an exemplary lower frame 4. FIG. In the embodiment shown, wire form spring clips 5 are attached to the lower frame and they serve as a means of reversibly attaching the lower frame to the upper frame. Suitable wire forms are made from any resilient metal wire known in the art that is suitable for wire spring clips, such as the 0.03 inch diameter piano wire used in this particular embodiment. be able to. Optional cutouts 6b are shown, which are preferably present on all four sides of the lower frame. The cutout 6b is aligned with the cutout 6a in the upper frame, opening 6 (Fig. 13) to allow indirect lighting to be directed upward from lighting elements (not shown) installed in the utilization channel. ) together. The lighting elements are preferably LED lamps with their associated wiring and are preferably mounted on a circuit board attached to the lower frame. Such circuit boards can be advantageously pre-installed in the lower frame, whereby the lighting is installed at the same time as the ceiling is installed. The installer of the ceiling panel corresponding to this embodiment has to plug the LED wires into the outlets connected to the power supply cables running inside the utilization channel 8 (Fig. 13) and complete the lighting of the ceiling. Provides code flexible installation.

9-11, the installation and in situ assembly of ceiling panels according to one embodiment of the present invention are shown in perspective views. First, as shown in FIG. 9, the upper frame 1 is placed on the T-bar grating 7 in a conventional manner so that the upper frame 1 rests on the upper surface of the T-bar flanges. The upper frame is pierced by four L-shaped slots 3. A lower frame 4 is shown with four wire form spring clips 5 attached near each corner. The wire spring clip stands vertically and features a first horizontal segment at the top and a second horizontal segment located near the midpoint of the wire and perpendicular to the first horizontal segment. . As can be seen at the end, the first and second horizontal segments project an L-shaped portion which is sized and oriented to align with the L-shaped slot 3 in the upper frame 1. be. The exact location of the slot 3 in the upper frame 1 and the exact location of the wire spring clip 5 on the lower frame 4 are not critical so long as they align when the frames come together. An alignment close to the corners is preferred to maximize the stability of the mounting panel. A symmetrical arrangement of slots and wires is preferred for ease of installation.

To install the panel into the T-bar grid, respective first horizontal segments of wire spring clips 5 are inserted into respective parallel projections of complementary L-shaped slots 3 . The lower frame 4 then moves upward until the first horizontal segment of the wire spring clip passes through the upper frame 1 and emerges from the slot 3 . The wire spring clip is preferably biased to displace away from the slot when each first horizontal segment emerges from its corresponding slot. Here, the arrangement is shown in FIG. 10, the lower frame 4 is shown hanging from the upper frame 1 by four wire spring clips 5 . In this configuration, installation and electrical connection of additional features such as wiring and electrical components may be performed.

The lower frame is pushed further upwards until the second horizontal segment of the spring wire clip 5 emerges from the slot 3 to complete assembly and installation of the panel. The wire springs are biased inwardly in a manner parallel to the sides of the frame, thereby displacing the second horizontal segment away from the slot 3 as it passes through it. The lower frame now depends from the upper frame and its weight is supported by the four second horizontal segments, as shown in FIG. In this configuration, the four wire spring clips are locked in the position indicated by the biasing force of the wire springs themselves. In this locking configuration, the two frames are in contact, or nearly in contact, so that the frames locked together act as a fixed unit that cannot be displaced from the T-bar.

In a preferred embodiment, the distance between the frames in the configuration of FIG. 10 allows placement of the upper frame on the T-bar grid after the lower frame has been connected using wire clips as shown in FIG. big enough to This mode of installation simply consists of installing the upper frame of the assembly shown in FIG. 12 over the T-bar grating to arrive at the arrangement shown in FIG. After making any necessary electrical connections, as explained above, the two frames are pushed together until the wire clips snap into place.

Separate the frames by manually displacing the wire spring clip 5 . A panel may be removed, thereby allowing the second horizontal segment to drop back into its corresponding slot, and then allowing the lower frame to drop downward, leaving the frame as shown in FIG. Revert to the configuration shown. Reversing the installation is simple from this point, the upper frame can be removed from the grid and then reinstalled afterwards without damage.

FIG. 13 shows the ceiling panel of the present invention, essentially along the lines of FIGS. shows a cross section. The wire clip 5 is omitted from this figure. In this embodiment, the sides of adjacent panels together define a utilization channel 8 beneath the T-bar. In an alternative embodiment (not shown), the sides of adjacent panels define utilization channels that are separate from the channels surrounding the T-bars 7 . As can be seen from Figure 13, the utilization channels 8 are below the T-bar grid and not inside the plenum space above the ceiling. This location outside the plenum allows installation of non-plenum rated wires and cables and simple plug connectors for lighting fixtures without the need for metal conduits, raceways and junction boxes. Cutouts 6a and 6b (see FIGS. 3 and 6) are aligned to define an aperture 6, which is used to admit light from a lighting element mounted inside utilization channel 8. be able to.

The drawings and descriptions provided herein are intended to be illustrative and not intended to convey limitations on the scope of the invention. Such modifications and variations, which will be obvious to those skilled in the art, are intended to be within the scope of the present invention.

Claims (7)

A ceiling panel for installation in a grid of suspended T-bars having vertical stems and horizontal flanges, said ceiling panel comprising:
(a) an upper frame that fits between the vertical stems and within the cells of the T-bar lattice and is sized to rest on the horizontal flanges of the T-bar lattice;
(b) a lower frame reversibly attachable to said upper frame when said upper frame rests on a horizontal surface of said grid of T-bars;
with
A ceiling panel, wherein said lower frame, when attached to said upper frame, together with said upper frame define a channel that at least partially encloses a horizontal flange of a T-bar on which said upper frame rests. 2. The ceiling panel of claim 1, wherein the lower frame is attached to the upper frame by spring wire retainer clips, the clips attached to one frame and engaging slots in the other frame. 3. The ceiling panel of claim 1, further comprising LED lighting elements attached to one of said frames. A suspended ceiling, said ceiling comprising:
(a) an inverted T-bar suspension grid with vertical stems and horizontal flanges;
(b) upper frames embedded between the vertical stems, each upper frame embedded within a cell of the T-bar lattice and resting on a horizontal flange of the T-bar lattice; an upper frame;
(c) a lower frame reversibly attached to said upper frame;
A suspended ceiling comprising
an adjacent lower frame, together with an adjacent upper frame to which said adjacent lower frame is attached, defines a channel that at least partially surrounds a horizontal flange of a T-bar on which said upper frame rests;
A suspended ceiling, wherein said frame cannot be separated from said T-bar when said frame is reversibly attached. 5. The suspended ceiling of claim 4, wherein the channel generally surrounds a horizontal flange of a T-bar on which the upper frame rests. A method of constructing a suspended ceiling, the method comprising:
(a) suspending a reciprocal lattice of T-bars from the existing ceiling;
(b) placing an upper frame between the vertical stems of the T-bar lattice, which fits within the cells of the T-bar lattice and rests on the horizontal flanges of the T-bar;
(c) reversibly attaching a lower frame to said upper frame;
including
wherein an adjacent lower frame, together with an adjacent upper frame to which said adjacent lower frame is attached, defines a channel that at least partially surrounds a horizontal flange of a T-bar on which said upper frame rests. 7. The method of claim 6, wherein the channel generally surrounds a horizontal flange of a T-bar on which the upper frame rests.

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