Although the following text sets forth a detailed description of numerous different embodiments of the invention, it should be understood that the legal scope of the invention is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment of the invention since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the invention.
It should also be understood that, unless a term is expressly defined in this patent using the sentence “As used herein, the term ‘______’ is hereby defined to mean . . . ” or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term be limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. §112, sixth paragraph.
In order to increase the strength of an end retention rolling shutter and to protect the supporting structure around the opening and to which the rolling shutter is mounted, a support frame is provided that is attached to the supporting structure so that the support frame engages the top and bottom walls defining the opening as well as the side walls. Once the support frame is attached to the support structure, the side tracks of the rolling shutter are secured to the side rails of the support frame, and the shutter housing is mounted on the side tracks to complete the installation. When the rolling shutter is subjected to negative pressure during a hurricane as discussed above, the support frame prevents a significant amount of torsion loading from being transmitted from the side tracks to the side walls on either side of the opening. The force resulting from the negative pressure is distributed around the support frame and borne by the fasteners connecting the support frame on all sides of the opening. Consequently, torsion loading concentrated on the side walls of the support structure may be greatly reduced or eliminated, thereby allowing the rolling shutter and support frame to withstand more severe hurricane conditions than is possible with the rolling shutter alone.
The rolling shutter assembly 130 is installed around the opening 12 by first mounting the support frame 132 to the support structure. Each of the rails 140-144 is fastened to the corresponding wall 134-138 defining the opening 12. However, the installation where the anticipated conditions and the strength of the support frame 132 may permit, the top rail 142 and bottom rail 144 may be disposed against the top wall 136 and bottom wall 138, respectively, without actually being attached to the walls 136, 138 with fasteners. After the support frame 132 is mounted to the opening 12, the side tracks 100 are attached to the corresponding side rails 140 of the frame 132. The side tracks 100 may be attached to the side rails 140 using any appropriate fasteners, such as bolts, rivets and the like. Alternatively, the side tracks 100 may be welded to the side rails 140. As a further alternative, each side rail 140 and corresponding side track 100 may be fabricated as a single unitary component such that the side tracks 100 are mounted to the opening along with the side rails 140 of the frame. Once the side tracks 100 are mounted to the support frame 132, the shutter housing is attached to the top ends of the side tracks 100 so that the shutter curtain contained therein may be unrolled into the space between the side tracks 100. If necessary and/or desired for further support, the shutter housing may also be attached to the top wall 136, the top rail 136, or both.
The transmitted torsion loads tending to rotate the side rails 140 and the side walls 134 to which they are attached are initially supported by the structure of the support frame 132 without transmission of the torsion loads to the walls or the fasteners. It should be noted that the direction and magnitude of the torsion loads will be determined based on the magnitudes and lines of action of the shear and tension loads, and the relative positions of the fasteners 150 and 154. Therefore, depending on the particular implementation of the rolling shutter assembly 130 and connection of its components, the torsion loads may tend to rotate the side rails 140 in the direction that pulls the top rail 142 and the bottom rail 144 away from the support structure, or in the direction that presses the top rail 142 and the bottom rail 144 against the support structure. In either case, the torsion loads are initially supported by the side rails 140 due to the rigidity of the support frame 132.
As the force FNP increases, the shear, tension and torsion loads correspondingly increase. Depending on the rigidity of the support frame 132, the torsion loading on the side rails 140 may eventually be sufficient to cause the side rails 140 to deflect and to begin applying the torsion loads to the framing elements of the side walls 134. At this point, the top rail 142 and the bottom rail 144 function as lever arms counteracting the twisting of the side rails 140 and reducing or eliminating the magnitude of the torsion load transmitted to the side walls 134. If the torsion load from the side tracks 100 rotates the side rails 140 in the direction to pull the top rail 142 and bottom rail 144 away from the walls 136, 138, respectively, the tension in the fasteners 152 and the fasteners connecting the bottom rail 144 provide a force tending to rotate the side rails 140 in the opposite direction against the torsion load. Conversely, if the torsion load from the side tracks 100 rotates the side rails 140 in the direction to press the top rail 142 and bottom rail 144 against the walls 136, 138, respectively, the reactive forces from the framing of the top and bottom walls 136, 138 against the top and bottom rails 142, 144, respectively, also tend to rotate the side rails 140 in the opposite direction against the torsion load. Consequently, in either configuration, the top rail 142 and bottom rail 144 provide the forces necessary to reduce or eliminate the torsion loading on the framing structure of the side walls 134.
The loads created during positive pressure conditions are generally supported in a similar manner. Shear and torsion loads are supported by the support frame 132 as discussed above and depending on the direction of application of the torsion loads. Therefore, torsion loading of the framing elements surrounding the opening is reduced or eliminated in positive pressure conditions as well. Instead of tension loading on the fasteners 150 due to the negative pressure force FNP as discussed above, positive pressures cause compression loading against the support frame 132 and, consequently, against the framing elements of the walls 134-138.
In addition to the load-bearing advantages of the support frame 132 as discussed above, the support frame 132 may also serve to align the rolling shutter assembly 130 or other covering when the surfaces surrounding the opening are uneven. The walls surrounding the opening may not necessarily be flat by design, or due to imperfections and flaws present when the structure was constructed or occurring afterwards. For example, stucco walls by their nature likely will not present a perfectly flat plane around the opening. Moreover, inartful plastering may create mounds and valleys in the outer surface of a wall that may prevent the side tracks 100 of the rolling shutter assembly 130 from being mounted evenly on the wall, and may prevent the side tracks 100 from being aligned on the walls without altering the walls or providing alignment mechanisms such as shims to ensure the side tracks 100 are square to each other and to the shutter curtain. These issues may be eliminated by the support frame 132 which, due to its rigidity, remains square to itself even when mounted on uneven surfaces such that the side rails 140 provide planar surfaces to which the side tracks 100 are attached despite the unevenness of the underlying walls surrounding the opening.
As discussed above, the support frame 132 may be fabricated as a single unitary component, or the rails 140-144 may be fabricated separately, cut to the appropriate lengths if necessary, and assembled to form the support frame 132.
While the rolling shutter assembly 130 is illustrated as covering an opening surrounded by a flat wall and having a recessed window, the rolling shutter assembly 130 may be configured to be mounted about or within other types of openings wherein the rolling shutter assembly 130 cannot simply be mounted against a flat exterior wall. For example, in many installations, obstructions in the way of the curtain path prevent the rolling shutter from being mounted flush against the exterior wall, and the rolling shutter must be disposed beyond the obstruction in order to close. Currently, build-out tubes having sufficient depth to allow the shutter curtain to avoid the obstruction are attached between the side walls and the side tracks of the rolling shutter assembly. However, the build-out tubes are not configured to extend across and be fastened to the top and/or bottom walls defining the opening. In such installations, the support frame 132 may be substituted for the build-out tubes to provide attachment to and support by the top and bottom walls of the opening as described above. The support frame 132 may be configured with sufficient depth to that the shutter curtain is disposed beyond the obstruction and is capable of being closed when necessary.
In other installations, the openings may not have sufficient vertical support structures for mounting the rolling shutter across a particular opening. For example, extremely wide openings cannot be covered by a single rolling shutter due to the planar profile and relatively small cross section of the rolling shutter curtain that make the shutter curtain very flexible and difficult to retain within the side tracks. Such wide openings may necessitate the installation of two or more rolling shutters disposed side-by-side and abutting to cover the entire width of the opening. In order to support the side tracks disposed within the opening, mullions are installed at the necessary positions within the opening, and the internal side tracks are attached to the corresponding mullions. In one embodiment, a separate support frame 132 may be provide with each individual rolling shutter assembly 130, and may have one of the side rails 140 connected between the corresponding side track 100 and mullion. Alternatively, and single support frame 132 may be provided that is dimensioned to surround the entire opening with the rails 140-144 fastened to the walls 134-138 as described above. In this embodiment, the support frame 132 may further include intermediate vertical rails securely connected between the top rail 142 and bottom rail 144 and disposed at positions corresponding to internal side rails 140 and mullions.
Modifications to the support frame 132 may be required when one of the walls extends outwardly at the opening while the remaining surrounding walls are flush with each other. Such a situation may exist when a rolling shutter is installed to cover a doorway or storefront such that a threshold extends outwardly at the bottom of the opening. In this type of installation, use a support frame 132 with the bottom rail 144 as described above may obstruct the doorway or storefront and create a tripping hazard when the shutter curtain is in its normal open position.
As discussed above, in certain installations deflection of the shutter curtain is minimized by providing a storm bar to redistribute the pressure loads on the rolling shutter and surrounding framing structure. Where the storm bar is located in front of the shutter curtain, a storm bar header is used to attach the top end of the storm bar proximate the shutter housing.
While the support frame 132 has been illustrated and discussed herein in combination with a rolling shutter covering an opening, those skilled in the art will understand that the support frame 132 may also be implemented in combination with flexible panels and fabric covers to reduce or elimination torsion loading on the framing elements. In contrast to the rolling shutter having the side rails 100 mounted to the side rails 140, a flexible panel or fabric cover may be attached to the top rail 142 and bottom rail 144 as well. With the added rigidity of the support frame 132, the torsion loads created by the flexible panels and fabric covers under positive pressure conditions as described above are supported by the frame 132 such that the torsion loads are not transmitted to the framing elements of the walls 134-138 surrounding the opening.
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While the preceding text sets forth a detailed description of numerous different embodiments of the invention, it should be understood that the legal scope of the invention is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment of the invention since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the invention.
This application is a continuation-in-part of U.S. Ser. No. 11/459,577, filed on Jul. 24, 2006, which application is expressly incorporated by reference herein.
Number | Date | Country | |
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Parent | 11459577 | Jul 2006 | US |
Child | 11781741 | US |