Patent Application
20130042560
1. Field of the Invention
The invention relates to noise control in suspended ceilings. Such suspended ceilings have a grid of intersecting metal beams that are suspended by hangers from a structural ceiling. Panels or drywall sheets are supported on the grid.
Noise generated in the structural ceiling, which is frequently a floor for the space above, is transmitted by sound vibrations passing downward through the hangers, which form a sound path, to the grid of the suspended ceiling. The suspended ceiling, which includes panels or drywall sheets attached to the beams in the grid, forms a receiver for the sound vibrations, which broadcasts the resulting unwanted noise to the space below.
The invention deals with deadening such sound vibrations coming down the hangers.
2. Prior Art
Suspended ceilings are constructed in a special way so that the ceilings are extremely stable. Over many years, a standard way of constructing such ceilings has evolved. Suspended ceilings are constructed at a building site by individually explosively embedding an anchor such as an eye bolt, into the structural ceiling, and then attaching a hanger, such as a wire, to the anchor, by twisting the wire about the anchor. The lower end of the hanger is attached to a metal beam in a grid that supports panels, or drywall sheets, by looping the hanger through a hole in the web of the beam and twisting the loop closed around the bulb and a segment of the beam.
The substantial weight of the suspended ceiling is spread among numerous hangers that are spaced every few feet along the main beams in the grid. Each hanger must be individually secured to the structural ceiling, and to the grid beam, by an installer who must keep the grid of interconnected main and cross beams level at a desired height. Much time and effort is required to hang a suspended ceiling grid from a structural ceiling.
Much more time and effort is required where sound attenuator devices that dampen the vibrations coming down a hanger sound path, from noise generated in a structural ceiling, are used.
In the prior art, to control noise in a suspended ceiling, a noise attenuator is individually inserted by the installer, about midway in the length of a wire hanger that is cut into two segments. An upper segment of the wire hanger is first secured at its top to the structural ceiling, and at its bottom, to a top terminal in the attenuator. A lower segment of the wire hanger is connected at the top to a bottom terminal in the attenuator, and then, at the bottom of the lower segment, to the grid beam.
In such prior art attenuator, the upper and lower metal terminals are separated from each other by a suitable amount of sound vibration damping material, such as gum rubber. Sound vibrations coming down the wire hanger sound path from the structural ceiling, which frequently serves as a floor for the building level above, are absorbed in the noise attenuator.
The insertion of such prior art noise attenuators in a wire hanger that must be divided into two segments is time and labor consuming, since the normally single segment of a wire hanger must not only be divided into two segments, but each segment must then be secured to the noise attenuator by passing the hanger through an attenuator terminal, and then twisting the hanger back around the segment. Thus, instead of just two attachments of a single segment of a wire hanger at an upper end to the structural ceiling, and at its lower end to a grid beam itself, as in prior art suspended ceilings with no noise attenuation, there are two additional attachments involving threading the wire hanger through a hole, and then twisting the wire hanger back upon itself, to the noise attenuator.
Such manual cutting, threading, and twisting must be individually custom performed by the installer of the grid in the field during the construction of the ceiling, since good judgment must be exerted at each wire hanger to keep the grid level, through controlling the length of the wire hanger suspensions.
A noise damper, of material that deadens sound vibrations coming down a hanger, is inserted between the grid beam and a hanger in the construction of the suspended ceiling.
The noise damper insulates the entire hanger attached to the structural ceiling from contact with the metal grid beam in the suspended ceiling, so the sound vibrations passing down the hanger are deadened in the noise damper. The noise damper, however, does not interfere with the structural support of the grid beam and suspended ceiling by the hangers, which are generally of wire, but permissibly of other material having adequate tensile strength to support the suspended ceiling.
The time required to install a suspended ceiling with the present invention is virtually the same as the time required to install a prior art suspended ceiling without any noise damping. In the present invention, the noise damper, which is of a resilient, sound vibration deadening material, can be merely inserted into place, and the hanger attached to the beam by looping a wire hanger through a knock-out in the beam, as done in the prior art in a suspended ceiling that is not sound dampened.
The knock-out can be shaped so the stress that the suspended ceiling imparts to the hanger where it passes through the knock-out is distributed over a section of the noise damper, rather than concentrated at the site of the hanger.
Although the invention is illustrated with hangers of wires, which is the predominant material used to suspend present day ceilings, the invention can be used with other forms of hangers, such as rods, or chains.
In
In
In the present invention, as shown in
At the top, the wire hanger 40 is looped through eye bolt 26 explosively embedded in structural ceiling 22, and the loop 44 is twisted closed. The lower end of wire hanger is passed through hole 61 in noise damper 41 on grid beam 21, and passes through knock-out 46.
Noise damper 41 has an inverted U-shaped upper portion 47 conforming in cross section to the bulb 48 of the grid beam 21, as seen particularly in
A raised insert 53 on flat lower portion 51 is shaped to conform to a knock-out 46, desirably with the shape of an arch 56 at the top. Lip retainers 57 hold the raised insert 53 firmly in the knock-out 46. An angled lip 58 on the U-shape clip portion 47 retains such U-shaped portion 47 of the noise damper 41 on the bulb 48 of the grid beam 21. A hole 61 that receives wire hanger 40 extends through the raised insert 53 and knock-out 46.
The noise damper 41 is injection molded into one resilient integral piece from a vibration deadening material. An example of such a material is thermoplastic vulcanizate, an elastomer, that includes carbon black and a paraffin wax. Such material, in pellet form, is injection molded into the form of the noise damper 41 insert of the invention. The noise damper 41, when molded, is flexible, and can readily expand when being inserted onto the grid beam 21, to envelope the grid beam 21 as depicted in the drawings.
The noise damper 41 is inserted onto the beam by passing the inverted U-shape portion 47 vertically downward over the bulb 48 of grid beam 21 to seat raised insert 53 in knock-out 46. The noise damper 41 expands while being inserted onto the grid beam 21, and contracts to the position about the beam 21, and into knockout 46, as shown particularly in
A single length of wire hanger 40, which has been embedded previously in the structured ceiling, is then looped through the hole 61 in the noise damper 41, as shown in
In this manner, the metal wire hanger 40 is insulated from metal grid beam 21, while still structurally supporting the grid beam 21.
A series of wire hangers 40 and noise dampers 41 are applied at, for instance, four (4) foot intervals along the main grid beams 21. The knock-outs 46 may be pre-punched at more frequent intervals, along the beam, and the noise dampers inserted selectively. The knock-outs 46 do not appreciatively affect the strength of the grid beams 21.
By means of the present invention, as set forth above, the hanger 40 which acts as a sound path from the structural ceiling 22 noise source to the suspended ceiling 43 which acts as a receiver is interrupted and dampened by the noise damper 41 of the invention.
The noise dampers 41 can be inserted at the job site as the grid beams 21 are being hung, or in the alternative, the noise dampers 41 can be inserted on the grid beams 21 before the grid beams 21 themselves are shipped to the job site.
In case of a fire, even though the noise dampers 41 of the invention are destroyed, wire hangers 40 continue to support the grid beams 21, since the wire hangers 40 remain attached to the grid beams 21.
