Title of Invention

"A BEAM FOR SUPPORTING DRYWALL SHEETS IN SUSPENDED CEILING"

Abstract

A balanced single-layered web beam (Fig.9) for a drywall suspended ceiling and a method of making the said beam wherein the binding (40) in the said beam runs longitudinally along the web (22) and binds second flange (23) and first flange (25) of the beam together, thereby cantilevering the second flange (23) from the first flange (25) along the bottom of the web (22), as a result, the resultant load of an equal vertical load on the flanges passes directly through the vertical plane of the single-layered web, thereby balancing the said single-layered web beam and resisting twisting and bending of the said beam, equivalent to a comparably sized two-layered web beam, but with the use of less metal.

Full Text

SINGLE-LAYERED WEB BEAM FOR A DRYWALL SUSPENDED CEILING This application is a continuation-in-part of the convention Application No.11/446,729 titled: SINGLE-LAYERED WEB BEAM FOR A SUSPENDED CEILING; filed with United States Patent and Trademark Office on June 5, 2006. The corresponding convention Indian Patent Application bearing No. 4074/DELNP/2007 was filed with the Indian Patent Office, New Delhi on May 30, 2007. BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention relates to beams that form a grid in a suspended ceiling that has drywall sheets attached to flanges in the beams. DESCRIPTION OF THE RELATED ART Beams used in grids for suspended ceilings of either the panel or drywall type are well known. Such beams, which are similar for both types of ceilings, have an inverted T cross section formed by continuously passing a strip of metal through rollers that fold the strip longitudinally. The beams carry a vertical load on the flanges only. vertical load on the flanges in suspended ceilings, beams symmetrical in cross section are used, so that the beam is loaded in the plane of the web. In the prior art, this is done with a double-layered web, having a flange cantilevered from each layer of the web, wherein the flanges oppose one another horizontally. Beams with a single-layered web have been tried, in an attempt to produce a beam that uses less metal. In such a beam that has a single-layered web, only a single flange is cantilevered from the web. An opposing flange is cantilevered from the first formed flange. Such a beam is unbalanced under a vertical load on both flanges, and is subject to twisting and bending, since it is not loaded in the plane of the web. In U.S. Patent Re 31,528, incorporated herein by reference, such problems with single-layered webs are discussed with reference to Figure 7 of the patent. In U.S. Patent 4,520,609, attempts were made to balance the cross section of a single-layered web beam by adding more material to the top and bottom of the beam on opposite sides of the web. In U.S. Patent 4,713,919, a beam having a web with a full first layer, and a partial second layer, is disclosed. In U.S. Patent 5,979,055, incorporated herein by reference, a beam having a web that is formed partially of one layer, is pieced together. Such prior art beams with a full, or partial, single-layered web were unbalanced and lacked the necessary strength and stiffness to support the loads, unless more and heavier material was used than in a double-layered web beam. This defeated the desire to use a single-layered web beam with its promise of the use of less metal to make the beam. Virtually all beams for suspended ceilings continue to have a double-layered web. BRIEF SUMMARY OF THE INVENTION In parent U.S. Patent Application 11/481,374 of which this application is a continuation-in-part, there is disclosed a balanced beam for a suspended ceiling formed with a single-layered web that has one flange bent and cantilevered from the bottom of the web, and a second, opposite flange, that is cantilevered from close to the web by a seam that secures the first and second flanges together close to the web. The seam is preferably formed by continuous stitching as the beam is being rollformed, as seen, for instance, in the '055 patent. Other forms of binding, such as spot, or continuous, welding, as well as adhesives, may be used to form the seam. Such a beam in cross section is balanced, and acts to load the beam in the plane of the web, so that any twisting or bending in a beam having a single-layered web is substantially eliminated. The seam also binds the flanges themselves together to produce a bottom member at the base of the single-layered web that stiffens the web itself. Such a single-layered web beam with a seam in the flanges along the web that binds the flanges together near the bottom of web, so that both flanges are cantilevered from the web, provides the equivalent strength and rigidity of a double-layered web formed of the same thickness of strip metal, but without using a second layer of the metal in the web, so there is less metal needed to make the beam. The present invention is directed to such a single-layered web beam adapted for use in a drywall suspended ceiling. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING Figure 1 is a partial perspective view of the basic single-layered web beam of the invention, taken from above. Figure 2 is a partial perspective view of the beam of Figure 1, taken from below. Figure 3 is a cross sectional view of a prior art beam with a double-layered web. Figure 4 is a cross sectional view of a prior art beam with a single-layered web. Figure 5 is a cross sectional view of the beam of Figures 1 and 2. Figure 6 is a view similar to Figure 1 showing a single-layered web beam adapted for use in a drywall suspended ceiling. Figure 7 is the beam of Figure 6 shown in a partial perspective view from below, similar to the view in Figure 2. Figure 8 is a cross sectional view of a prior art beam used in a drywall ceiling. Figure 9 is a cross sectional view of the beam of the invention adapted for use in a drywall suspended ceiling. Figure 10 is a partial cross sectional view of a suspended drywall ceiling, showing the prior art beam of Figure 8, and the single-layered web beam of the invention adapted for use in a drywall suspended ceiling, having attached drywall sheets. DETAILED DESCRIPTION OF THE INVENTION Beams 20 for suspended ceilings are shown in Figures 1 through 5. Such beams include the prior art beams shown in Figures 3 and 4, and the single-layered web beam of the invention shown in Figures 1, 2, and 5. Beams 20 have a bulb 21 at the top of a web 22. Opposing flanges 23 and 25 extend horizontally away from the web at the bottom of the beam. The vertical panel load, or vertical drywall load, on the beams in a suspended ceiling, is indicated in Figures 3 through 5 by vectors that represent the amount, location, and direction of the load exerted by the panels or drywall in a suspended ceiling. The load on each flange is indicated by vectors 26 and 27 on the prior art beams shown in Figures 3 and 4, and on the beam of the invention shown in Figure 5. The prior art beam 20 shown in Figure 3 has a two-layered web 22, with each of the flanges 23 and 25 cantilevered from one of the layers of the web 22. The beam is symmetrical, and hence balanced, in cross section. The prior art beam 20 shown in Figure 4 has a single-layered web 22 with a flange 25 cantilevered from the bottom of the web 22, to the right, and then a second opposing flange 23 cantilevered from flange 25 at location 29, in a direction to the left. The basic single-layered web beam 20 of the invention, as seen in Figures 1, 2, and 5, has a single-layered web 22, with the flanges formed as in the prior art beam 20 of Figure 4 . The basic single-layered web beam 20 of the invention as seen for instance in Figures 1, 2, and 5, also has a seam 40 that runs longitudinally along the web 22 of the beam, that binds flanges 23 and 25 together, so that flange 23 is cantilevered from flange 25 along web 22. The seam 40 is preferably made as the beam is being continuously roll formed, as by stitching. A form of stitching is disclosed in U.S patent '055 cited above. A seam 40 could also be formed by continuous or spot welding, or by adhesives. Seam 40, in effect, cantilevers the flange 23 from the single-layered web 22 of the basic beam 20 of the invention as seen for instance in Figures 1, 2, and 5, so that the result is a balanced beam that is loaded through the plane of the single-layered web 22. Such basic beam 20 of the invention resists twisting and bending to an extent equivalent; to that of a prior art double-layered web beam of a comparable size made of the same thickness metal strip, as seen for instance in Figure 3. The beam of the invention however, uses less metal. In Figures 3, 4, and 5 of the drawings, the loading of the beams 20, both prior art and of the invention, is shown through the use of vectors. In Figure 3, load vectors 26 and 27 represent the vertical loading on each of the flanges 23 and 25 of a double-layered prior art beam 20, in either a panel or drywall suspended ceiling. The resultant load vector 30 of vectors 26 and 27 of such prior art double-layered web beam passes through the plane of web 22, since the beam is balanced. Such balanced beam creates a maximum resistance to bending and twisting. In Figure 4, there is shown the single-layered beam of the prior art. Again, as in Figure 3, the vectors 26 and 27 represent the loads applied to the beams, either through panel, or drywall, loads. However, because of the beam construction wherein flange 23 is cantilevered from flange 27 at location 29, the resultant load vector 31 is shown applied at a distance away from the single-layered web, resulting in an unbalanced beam subject to bending and twisting that is not present in the balanced beam of Figure 3. In Figure 5, which shows the basic single-layered web beam 20 of the invention, again, as in the prior art, the beam 20 is vertically loaded on the flanges 23 and 25, in the suspended ceiling, as shown by vectors 26 and 27. However, seam 40 binds flange 23 to flange 27 along web 22, so that in effect both flanges 23 and 25 are cantilevered from web 22, resulting in a balanced beam. Load resultant 32 passes through the plane of the web 22, so that the single-layered basic beam 20 of the invention resists twisting and bending equivalent to a comparably sized two-layered web beam 20, as seen in Figure 3, but with the use of less metal. There is shown in Figures 8 and 10, for use in a drywall suspended ceiling, a prior art two-layered beam, as disclosed in U.S. Patent 6,722,098, incorporated herein by reference. There is shown in Figures 6, 7, 9, and 10, the basic single-layered web beam of the invention adapted for use in a drywall suspended ceiling. Such beam is designated 20'. Both the prior art beam 20 as shown for instance in Figures 8 and 10, and the beam 20' of the invention adapted for drywall in Figures 6, 7, 9, and 10, have a bulb 21 or 21', a web 22 or 22', and opposing flanges 23 and 25 or 23' and 25'. The prior art two-layered web beam 20 of Figure 8 is stitched together at 67, longitudinally of the web 22, as described in detail in the '098 patent. In such prior art beam, hems 65 serve to retain the point 71 of self-tapping screws 11 in contact with an indent 60 in the flanges 23 and 25 of the beam 20, whereby the screw 11 can pierce the flanges and secure the drywall sheet 70 to the flanges 23' and 25' . In the basic single-layered web beam of the invention 20' adapted for drywall suspended ceilings, as seen in Figures 6, 7, 9, and 10, hems 65 are formed in the single-layered flange 23' extending to the left from the web 22', as seen in such Figures, and in the double-layered flange 25' extending to the right from the web 22', as also seen in such Figures. The drywall sheets 70, when secured to the flanges 23 and 25 of the prior art double-layered web beam 20 as seen on the left in Figure 10, exert a vertical downward load, as shown by vectors 23 and 25 in Figure 3. The drywall sheets 70, when secured to the flanges 23' and 25' of the basic single-layered web beam 20' of the invention adapted for drywall, as seen in Figure 10, also exert a vertical downward load, as seen in Figure 5. As discussed above, the prior art double-layered web beam 20 is symmetrical, and balanced, and, as seen in Figure 3, the total load 30 on the beam, which is the sum of the loads exerted on each flange, passes through the plane of the web 22, with a minimum of bending and twisting on the beam 20. The beam 20' of the invention adapted for a drywall suspended ceiling likewise is balanced, as explained above, and shown in the drawings, since the seam 40 along the web acts to cantilever both flanges 23' and 25' from the web 22', so that the total load 32, as seen in Figure 5, passes through the plane of the single-layered web 22'. Since the load is balanced in the basic single-layered web beam 20' of the invention as adapted for drywall, there is a minimum of twisting and bending on the beam 20' from the downward loads of the drywall sheets 70. There is a savings in metal with the basic single-layered web balanced beam of the invention for a drywall suspended ceiling 20' over a comparable sized prior art balanced double-layered web beam 20 as seen in Figures 8 and WE CLAM: 1. A balanced single- layered web beam for a drywall suspended ceiling, wherein the beam is formed from a strip of metal folded longitudinally into a cross section having a) a bulb (21) at the top b) a vertical single-layered web (22) extending downward from the bulb c) a first flange (25) cantilevered horizontally from the bottom of the web in the first direction d) a second flange (23) cantilevered horizontally from the first flange (25) in a second direction opposite to the first direction e) the binding (40) between the two flanges characterized in that the binding (40) in the said beam runs longitudinally along the web (22) and binds second flange (23) and first flange (25) of the beam together, thereby cantilevering the second flange (23) from the first flange (25) along the bottom of the web (22), and as a result of that, the resultant load (32) of an equal vertical load (26, 27) on the flanges passes directly through the vertical plane of the single-layered web, thereby balancing the said single-layered web beam and resisting twisting and bending of the said beam, equivalent to a comparably sized two-layered web beam, but with the use of less metal. 2. Beam as claimed in claim 1 wherein the beam is further formed from a strip of metal folded longitudinally into a cross section having a) downwardly extending hems (65) that reinforce the flanges (23 and 25) and retain self- tapping drywall attachment screws on the flanges, and b) upward indentations on the bottom of the flanges. 3. Beam as claimed in claim 1 or claim 2 wherein the binding is formed by a seam of stitches. 4. Beam as claimed in claim 1 or claim 2 wherein the binding is formed by a seam by continuous or spot welding, or by adhesive. 5. Beam as claimed in claim 1 or claim 2 wherein the binding stiffens the web. 6. Method of making balanced single layered web beam as claimed in claim 1 or claim 2 by a binding(40) that runs longitudinally along the web (22) and binds second flange (23) and first flange (25) of the beam together, thereby cantilevering the second flange (23) from the first flange (25) along the bottom of the web (22), as a result, the resultant load (32) of an equal vertical load (26, 27) on the flanges passes directly through the vertical plane of the single-layered web, thereby balancing the said single-layered web beam and resisting twisting and bending of the said beam, equivalent to a comparably sized two-layered web beam, but with the use of less metal. 7. Method as claimed in claim 6 wherein the binding is formed by a seam of stitches. 8. Method as claimed in claim 6 wherein the binding is formed by a seam by continuous or spot welding, or by adhesive. 9. Method as claimed in claim 6 wherein the binding stiffens the web.

Documents:

1419-del-2007-Abstract-(13-06-2013).pdf

1419-DEL-2007-Abstract-(30-03-2012).pdf

1419-del-2007-abstract.pdf

1419-del-2007-assignment.pdf

1419-del-2007-Claims-(13-06-2013).pdf

1419-DEL-2007-Claims-(30-03-2012).pdf

1419-del-2007-claims.pdf

1419-DEL-2007-Correspondence Others-(30-03-2012).pdf

1419-del-2007-Correspondence-Others-(13-06-2013).pdf

1419-del-2007-correspondence-others.pdf

1419-del-2007-description (complete).pdf

1419-del-2007-drawings.pdf

1419-DEL-2007-Form-1-(30-03-2012).pdf

1419-del-2007-form-1.pdf

1419-del-2007-form-18.pdf

1419-del-2007-Form-2-(13-06-2013).pdf

1419-del-2007-Form-2-(30-03-2012).pdf

1419-del-2007-form-2.pdf

1419-DEL-2007-Form-3-(30-03-2012).pdf

1419-del-2007-form-3.pdf

1419-del-2007-Form-5-(13-06-2013).pdf

1419-del-2007-form-5.pdf

1419-del-2007-GPA-(13-06-2013).pdf