FREE SPAN CEILING GRID SYSTEM
Components for constructing a ceiling grid across a span free of or with a limited number of suspension wires including main runners with a relatively high moment of inertia secured at their ends with brackets to wall moldings on opposing walls.
The invention relates to suspended ceilings and, in particular, to grid elements that eliminate or reduce the number of mid-span suspension wires or like elements required to adequately support the ceiling assembly.
PRIOR ARTCommonly, the grid of a suspended ceiling is supported by wires depending from overhead structure such as an overlying floor or roof. There are circumstances, as in corridors, where the plenum or space above the ceiling is occupied by utilities, such as air and wire ducts, making it difficult or impractical to use wires for carrying the weight of a ceiling. In other circumstances, there may only be a limited number of places to attach wires to the overhead structure and/or to the grid elements. In still other circumstances, labor and overall installation costs can be lowered where the number of wires needed for an installation is reduced.
There have been proposals such as disclosed in U.S. Pat. No. 7,240,460 and U.S. patent publication US 2010/0257807 A1 for free span suspended ceilings.
SUMMARY OF THE INVENTIONThe invention provides a ceiling grid system with high moment of inertia grid runner, end brackets and wall mounted runner end supports. Optional elements of the system include splice plates and runner-to-runner cross hanger brackets. The disclosed system is capable of spanning an area without or with limited overhead wire support.
In the disclosed embodiment, the high moment of inertia grid runners are primarily used as main runners or tees that cooperate with cross runners in a generally conventional manner. End brackets are manually attached to main runners typically at the grid installation site after the main runners are confirmed to fit or have been cut to fit the span across which they are to be installed.
Preferably, an end bracket interfits with the physical characteristics of the main runner so that only a single screw fastener is required to rigidly fix the bracket to the runner.
The disclosed grid runner end supports are in the form of roll formed sheet metal channels that are affixed to the walls at the edge of the ceiling. The channel flanges can be of different widths so that the channel can be oriented with a wide or narrow flange visible from the space below the ceiling. The flanges have inturned hems that are engaged by tab elements of the end brackets for a quick snap-in provisional mounting. An end bracket can be locked on the channel at a desired location with a screw fastener through a web of the channel.
In moderate span length applications such as in a corridor of 8 foot (or metric equivalent) for an acoustical ceiling, the disclosed system can eliminate the need for intermediate overhead support wires or like members. In longer spans, the system can reduce the number of suspension wires that would otherwise be required. For such longer spans, a splice plate is provided to enable the high moment of inertia grid runner to be connected end-to-end. Additionally, the splice plate can be bent into a right angle for connecting intersecting grid runners to the main runner.
A cross brace clip is disclosed that suspends a high moment of inertia grid runner with an identical grid runner to reduce the number of necessary suspension wires and/or enable a main runner to be suspended where no directly overhead structure is available for its support.
As is conventional, cross runners 13, 14 have end connectors assembled in receiving slots 17 of the main runners 12 and cross runners 13. Ends of the main runners 12 and cross runners 14 are supported by wall channels 19.
The main runners 12 have the general cross section of an inverted tee with a hollow upper generally oval reinforcing bulb 21, a vertical web 22 depending from the bulb, and a flange 23 symmetrically disposed about a lower edge of the web. The illustrated bulb 21 is substantially wider than it is tall. By way of example, but not limitation, the main runner 12 can have a height of about 2¾ inch which, when compared to a typical 1.640 inch height conventional intermediate duty main grid runner, is relatively tall. The height of the main runner 12, width of its reinforcing bulb 21 and heavier gauge results in a runner that has a high moment of inertia about its longitudinal bending axis. Consequently, the runner 12 can support a relatively high load distributed along its length. For example, the main runner 12, formed of 0.022 inch thick G-30 hot-dipped galvanized steel place on 4 foot centers such as is shown in
The ceiling load on a main tee 12 is transferred at each end to a respective wall channel 19 through an end bracket 26. The end bracket 26 is shown separately in
The wall channel 19 is preferably roll formed of sheet metal of, for example, G-30 hot dipped galvanized steel of 0.020 inch thickness. The illustrated channel 19 has flanges 41, 42 of different widths and extending generally perpendicularly from a common web 43. The wider flange 41 is, for example, nominally 1 inch wide and the narrow flange 42 is nominally ½ inch wide. These flange dimensions correspond to the flange face width of standard and narrow face commercially available grid common in the industry. The channel flanges 41, 42 have inturned hems 44 associated with marginal edges 45 of the metal strip forming the channel 19. The flanges 41, 42 are spaced to receive the height of the main runner 12.
As shown in
The end brackets 26 have resilient tabs 48-50 on upper and lower edges of the channel engaging portion 29. The upper tab 48 extends the full length of the portion 29 and a lower middle tab 49 extends between outlying lower tabs 50. With reference to
Typically, the channel 19 is secured to a wall by self-drilling drywall screws 55 (
From the foregoing, it will be seen that for the spans of about 8 feet the runners 12 and the acoustical ceiling elements they carry are supported exclusively at their ends. The brackets 26 are capable of fully providing this support although a support contribution can be provided by a lower channel flange 41 or 42.
In
In the foreground of
A physical situation may exist where a main runner 12 cannot be supported exclusively at its end. For example, may be an absence of a suitable attachment point for a suspension wire or strap overlying the main runner or runners involved.
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.
Claims
1. A suspended ceiling grid comprising a plurality of parallel regularly spaced main runners, each one of a pair of opposed oppositely facing channels being disposed adjacent one end of said main runners, said channels each having a vertical web and a horizontal flange at top and bottom edges of the web, a bracket at each end of each main runner, the bracket being attached to the main runner with a first self-drilling screw and to the web of the channel with a second self-drilling screw, each main runner extending in one piece from one channel to the other channel and being exclusively supported by the channels with sufficient support capacity to permit the main runners to support a conventional acoustical ceiling while being free of suspension wires or other overlying support elements along the full length of the main runners between said channels, each main runner having an upper reinforcing bulb and a lower flange, the bracket having a main runner engaging portion with upper and lower edges extending along the portion, the lower edge being straight along its full flange engaging length and fitted to the flange such that there is essentially no ability of the bracket to rotate perceptively relative to the main runner and otherwise allow the main runner to droop perceptively below its originally installed position, the flange at the top of the channel web serving to stiffen the channel web to prevent the channel web from pulling away from the respective wall due to a load imposed on the channel by the main runners.
2. A suspended ceiling grid as set forth in claim 1, wherein said main runners support acoustical panels and are about 8 feet or greater in length.
3. (canceled)
4. (canceled)
5. A suspended ceiling grid as set forth in claim 1, wherein said channel is roll formed sheet metal.
6. A suspended ceiling grid as set forth in claim 5, wherein said upper and lower flanges have inturned hems at their distal margins.
7. A suspended ceiling grid as set forth in claim 6, wherein said brackets have tabs proportioned to lock into said channels between said hems and said web.
8. A suspended ceiling grid as set forth in claim 7, wherein the flanges of said channels are of different widths corresponding to face widths of conventional grid runner face widths.
9. A suspended ceiling grid as set forth in claim 8, wherein said bracket has a functional orientation and has multiple tabs of different lengths at a lower edge.
10. A suspended ceiling grid comprising a plurality of parallel regularly spaced main runners, each one of a pair of opposed oppositely facing channels being disposed adjacent one end of said main runners, said channels each having a vertical web and a horizontal flange at top and bottom edges of the web, a bracket at each end of each main runner, the bracket being attached to the main runner and with a first self-drilling screw and to the web of the channel with a second self-drilling screw, each main runner extending in one piece from one channel to the other channel and being exclusively supported by the channels with sufficient support capacity to permit the main runners to support a conventional acoustical ceiling while being free of suspension wires or other overlying support elements along the full length of the main runners between said channels, said channels being roll formed sheet metal, said upper and lower flanges having inturned hems at their distal margins, said brackets having tabs proportioned to lock into said channels between said hems and said web, the flanges of said channels being of different widths corresponding to face widths of conventional grid runner face widths, said bracket having a functional orientation and having multiple tabs of different lengths at a lower edge, said multiple tabs including a lower tab that is bendable from a generally horizontal orientation to a generally vertical orientation to allow another tab of said multiple tabs shorter than said bendable tab to engage a hem edge of a narrow one of said flanges.
11. In combination, a metal grid runner, a generally L-shaped bracket with first and second perpendicular legs, the first leg being arranged to be attached to a side of the grid runner at an end thereof, the second leg having upper and lower tabs for engaging inturned hems at flanges of a sheet metal C-shaped channel when inserted into the channel, the lower tabs having two different generally horizontal lengths whereby the bracket can be retained by a shorter tab when the channel has a lower shorter flange and by a longer tab when the channel has a lower longer flange.
12. The combination as set forth in claim 11, wherein the first leg has a vertical height greater than a standard grid tee height.
13. A sheet metal bracket for supporting a grid runner from a channel shaped wall molding, the bracket having a right angle configuration in plan view, a first portion of the bracket having an aperture for receiving a screw to attach the first portion to a web of the grid runner, a second portion having an aperture for a screw to attach the second portion to the web of a channel wall molding, the second portion having a generally horizontal tab extending from said second portion towards said first portion with a free edge adapted to engage an edge of an inturned hem of a wall channel.
14. In combination, a grid runner, a right angle bracket, and a wall molding having a vertical web and a horizontal flange at a top of the web, the bracket being separately fixed to the wall molding with a first screw and to the grid runner with a second screw.
15. The combination as set forth in claim 14, wherein the molding is a channel.
16. The combination as set forth in claim 15, wherein the channel has horizontal flanges with inturned hems, said bracket having tabs adapted to be snap locked into said channel by operation of said tabs against said hems.
17. A combination as set forth in claim 16, wherein said channel flanges are of different lengths.
18. The combination as set forth in claim 17, wherein said bracket has tabs of different lengths corresponding to the different channel flange lengths.
19. The combination as set forth in claim 18, wherein said bracket has a short tab at an upper portion of the bracket and short and long tabs on a bottom portion of the bracket.
20. The combination as set forth in claim 14, wherein the grid runner has a vertical space between an upper reinforcing bulb and a lower flange, said bracket being sized to fit between said reinforcing bulb and flange in a sufficiently tight manner to avoid perceptible rotational movement therebetween.
21. The combination as set forth in claim 20, wherein said bracket has a horizontal channel at mid-height to receive a reinforcing bulb of a grid runner having less height than said first mentioned grid runner.
22. The combination as set forth in claim 21, wherein said bracket has preformed holes for receiving self-drilling screws.
23. The combination as set forth in claim 14, wherein said bracket has an elongated slot for use in seismic zones.
24. A splice plate for a high moment of inertia grid runner comprising a sheet metal plate, the plate having a generally rectangular profile and a horizontal length greater than a vertical height, the plate being formed with a horizontal channel at mid-height, a vertical slot in a mid-section of the plate including the horizontal channel, the slot forming a line of weakness to enable a technician to manually bend the plate into a right angle, the slot having a width sufficient to avoid interference between sections of the channel on opposite sides of the slot when the plate is bent with the channel projecting into the space towards which the plate sections are bent, the plate sections having a plurality of through holes for accepting self-drilling screws for attaching the plate to a grid runner.
25. A sheet metal bracket for suspending a first grid runner from a second grid runner extending over and crosswise to the first grid runner, the bracket having a generally right angle configuration in plan view, an upper portion of the bracket having a plurality of holes for receiving self-drilling screws for attaching the second grid runner, the first portion being integrally attached to the second portion and extending below the second portion, the first portion having an offset bend below said second portion and a flat part below said offset, said flat part having through holes for receiving self-drilling screws for fixing said flat part to a web of the first grid runner.
Type: Application
Filed: Aug 19, 2014
Publication Date: Feb 25, 2016
Inventors: James J. Lehane (McHenry, IL), Lee M. Tedesco (Shorewood, IL), Peder J. Gulbrandsen (Aurora, IL), John M. Willi (Westlake, OH), Donald J. Leahy (North Olmsted, OH), Abraham M. Underkofler (Waukegan, IL), Yelena Straight (North Buffalo Grove, IL), Michael O'Donnell (Modesto, CA)
Application Number: 14/462,716