Unitized structural frame

Abstract

An improvement in a rolling shutter assembly for covering an opening of a structure defined by a top wall, a bottom wall and oppositely disposed side walls. The rolling shutter assembly includes a shutter housing, a shutter support member rotatably disposed within the shutter housing, a shutter coupled to the shutter support member, the shutter comprising a plurality of individual slats and a plurality of hinges interconnecting the slats, and a pair of side tracks. The shutter rolls between a rolled position wherein the shutter is rolled onto the shutter support member and an unrolled position wherein the shutter covers the opening and the ends of the slats are disposed within the channels of the corresponding side tracks. The improvement comprises a support frame having top, bottom and side rails mounted to the walls defining the opening with the side tracks each mounted to a corresponding one of the side rails of the support frame. The support frame reduces or eliminates the transmission of torsion loads from the shutter to the framing elements of the walls during positive and negative pressure conditions.

Claims

1. A rolling shutter assembly for covering an opening of a structure defined by a support structure having a top wall, a bottom wall and oppositely disposed side walls, the rolling shutter assembly providing hurricane protection for the opening during a hurricane, the assembly comprising: a shutter housing; a shutter support member rotatably disposed within the shutter housing; a shutter coupled to the shutter support member, the shutter comprising a plurality of individual slats and a plurality of hinges interconnecting the slats; a pair of side tracks, wherein the shutter housing is mounted proximate the top ends of the side tracks such that the shutter rolls between a rolled position wherein the shutter is rolled onto the shutter support member and an unrolled position wherein the shutter covers the opening and the ends of the slats are disposed within the channels of the corresponding side tracks with the side tracks engaging the ends of the slats to retain the ends of the slats within the side tracks such that the side tracks deflect inward toward each other and twist relative to the side walls when the shutter is in the unrolled position and the loading caused by the hurricane is applied to the shutter and the side tracks; and a support frame having a top rail, a bottom rail, a pair of oppositely disposed side rails connected to the top rail and the bottom rail to form the support frame with a corner defined at each connection between an end of one of the side rails and a corresponding end of one of the top rail and the bottom rail, and a plurality of structural support members each disposed at one of the corners of the support frame and attached to the side rail and to the top rail or the bottom rail to which the side rail is connected at the corresponding corner to transfer torsional loads created by the side tracks on the side rails to the top rail and the bottom rail, wherein the side tracks are each mounted to a corresponding one of the side rails of the support frame, wherein the support frame is mounted to the walls of the support structure defining the opening with the top rail anchored to the top wall with a first plurality of fasteners extending through the top rail and into the top wall, the bottom rail anchored to the bottom wall with a second plurality of fasteners extending through the bottom rail and into the bottom wall, and the side rails disposed proximate the corresponding side walls and not secured to the side walls with fasteners extending through the side rails and into the side walls so that the side rails deflect inward toward each other and twist relative to the side walls and do not apply twisting and torsion loads to the side walls when loads are applied to the side rails by the side tracks when the shutter is in the unrolled position and the loading on the shutter caused by the hurricane causes the side tracks to deflect inward toward each other and twist relative to the side walls, and wherein the loading caused by the hurricane is transferred by the structural support members from the side rails to the top and bottom rails and the top and bottom walls.

2. A rolling shutter assembly as defined in claim 1, wherein the side rails of the support frame are against the corresponding side walls of the support structure defining the opening.

3. A rolling shutter assembly as defined in claim 1, wherein one of the side walls defining the opening is a mullion, and wherein one of the side rails of the support frame is disposed against the mullion.

4. A rolling shutter assembly as defined in claim 1, wherein the opening has a mullion extending between and connected to the top wall and the bottom wall defining the opening, wherein the support frame comprises an intermediate vertical rail extending between and connected to the top rail and the bottom rail and positioned to align with the mullion when the support frame is attached to the walls, and wherein the intermediate vertical rail is anchored to the mullion and one of the side tracks of the rolling shutter assembly is anchored to the intermediate vertical rail.

5. A rolling shutter assembly as defined in claim 1, wherein the top and the side rails are hollow tubes, wherein the ends of the top and the side rails are beveled such that the adjoining rails form a mitered corner, and wherein the support frame comprises a plurality of L-shaped unitizing inserts each disposed at one of the corners of the support frame with one leg extending into the end of each of the adjoining rails, and wherein each leg of the L-shaped unitizing insert is connected to the corresponding end of one of the rails to secure the ends of the adjoining rails forming the corner.

6. A rolling shutter assembly as defined in claim 1, wherein the top, the bottom and the side rails are hollow tubes having front, rear, inside and outside walls, wherein inside and rear walls of the side rails do not extend to the ends of the side rails, and wherein the ends of the top and bottom rails abut inner surfaces of the outside walls at the corresponding ends of the side rails when the support frame is assembled.

7. A rolling shutter assembly as defined in claim 1, wherein the bottom wall defining the opening extends outwardly from the structure beyond the opening, wherein the side rails are hollow tubes, and wherein the bottom rail comprises a flat plate having at least one upwardly extending flange at each end extending upwardly into the end of a corresponding one of the side rails to connect the plate to the side rails.

8. A rolling shutter assembly as defined in claim 1, wherein the support frame comprises a lever arm connected to and extending between the side rails of the support frame at a height proximate the bottom of the shutter housing, the assembly comprising: a storm bar header connected to the frame at the height of the lever arm and disposed on the opposite side of the side tracks as the frame and the opening; and a storm bar having one end connected to the storm bar header and the opposite end connected to the bottom wall.

9. A rolling shutter assembly as defined in claim 8, wherein the side rails and the lever arm are hollow tubes, wherein each side rail has an opening through an inner wall of the side rail at the location where the end of the lever arm abuts the side rail, and wherein the support frame comprises a pair of unitizing inserts each inserted into an end of the lever arm and into the opening through the inner wall of the corresponding side rail.

10. A method for mounting a rolling shutter assembly to support structure surrounding an opening of a building, the rolling shutter assembly providing hurricane protection for the opening during a hurricane, wherein the opening is defined by a support structure having a top wall, a bottom wall and oppositely disposed side walls, wherein the assembly comprises a shutter housing, a shutter support member rotatably disposed within the shutter housing, a shutter coupled to the shutter support member, the shutter comprising a plurality of individual slats and a plurality of hinges interconnecting the slats, a pair of side tracks, and a support frame having a top rail, a bottom rail, a pair of oppositely disposed side rails connected to the top rail and the bottom rail to form the support frame with a corner defined at each connection between an end of one of the side rails and a corresponding end of one of the top rail and the bottom rail, and a plurality of structural support members each disposed at one of the corners of the support frame and attached to the side rail and to the top rail or the bottom rail to which the side rail is connected at the corresponding corner to transfer torsional loads on the side rails to the top rail and the bottom rail, the method comprising: mounting the support frame to the support structure with the top rail anchored to the top wall with a first plurality of fasteners extending through the top rail and into the top wall, the bottom rail anchored to the bottom wall with a second plurality of fasteners extending through the top rail and into the top wall, and the side rails disposed proximate the corresponding side walls and not secured to the side walls with fasteners extending through the side rails and into the side walls so that the side rails can deflect inward toward each other and twist relative to the side walls during loading on the shutter caused by the hurricane without causing loads on the side walls; mounting each of the side tracks to a corresponding one of the side rails of the support frame; and mounting the shutter housing proximate the top ends of the side tracks such that the shutter rolls between a rolled position wherein the shutter is rolled onto the shutter support member and an unrolled position wherein the shutter covers the opening and the ends of the slats are disposed within the channels of the corresponding side tracks with the side tracks engaging the ends of the slats to retain the ends of the slats in the side tracks such that the side tracks deflect inward toward each other and twist relative to the side walls when the shutter is in the unrolled position and the loading caused by the hurricane is applied to the shutter and the side tracks, wherein the side rails deflect inward toward each other and twist relative to the side walls and do not apply twisting and torsion loads to the side walls when loads are applied to the side rails by the side tracks when the shutter is in the unrolled position and the loading caused by the hurricane is applied to the shutter and the side tracks and causes the side tracks to deflect inward toward each other and twist relative to the side walls, and wherein the loading caused by the hurricane is transferred by the structural support members from the side rails to the top and bottom rails and the top and bottom walls.

11. A method as defined in claim 10, wherein one of the side walls defining the opening is a mullion, the method comprising anchoring one of the side rails of the support frame to the mullion.

12. A method as defined in claim 10, wherein the opening has a mullion extending between and connected to the top wall and the bottom wall defining the opening, wherein the support frame comprises an intermediate vertical rail extending between and connected to the top rail and the bottom rail and positioned to align with the mullion when the support frame is attached to the walls, the method comprising: anchoring the intermediate vertical rail to the mullion; and anchoring one of the side tracks of the rolling shutter assembly to the intermediate vertical rail.

13. A method as defined in claim 10, wherein the support frame comprises a lever arm connected to and extending between the side rails of the support frame at a height proximate the bottom of the shutter housing, the method comprising: connecting a storm bar header to the frame at the height of the lever arm with the storm bar header being disposed on the opposite side of the side tracks as the frame and the opening; and connecting one end of a storm bar to the storm bar header and the opposite end of the storm bar to the bottom wall.

14. A method as defined in claim 10, wherein the side tracks are mounted to the side rails before the shutter housing is mounted proximate the top ends of the side tracks.

15. A method as defined in claim 10, wherein the shutter housing is mounted proximate the top ends of the side tracks before the side tracks are mounted to the side rails.

16. In a rolling shutter assembly for covering an opening of a structure defined by a support structure having a top wall, a bottom wall and oppositely disposed side walls, the rolling shutter assembly providing hurricane protection for the opening during a hurricane, the assembly having a shutter housing, a shutter support member rotatably disposed within the shutter housing, a shutter coupled to the shutter support member, the shutter comprising a plurality of individual slats and a plurality of hinges interconnecting the slats, and a pair of side tracks, and wherein the shutter housing is mounted proximate the top ends of the side tracks such that the shutter rolls between a rolled position wherein the shutter is rolled onto the shutter support member and an unrolled position wherein the shutter covers the opening and the ends of the slats are disposed within the channels of the corresponding side tracks with the side tracks engaging the ends of the slats to retain the ends of the slats in the side tracks such that the side tracks deflect inward toward each other and twist relative to the side walls when the shutter is in the unrolled position and the loading caused by the hurricane is applied to the shutter and the side tracks, the improvement comprising: a support frame having a top rail, a bottom rail, a pair of oppositely disposed side rails connected to the top rail and the bottom rail to form the support frame with a corner defined at each connection between an end of one of the side rails and a corresponding end of one of the top rail and the bottom rail, and a plurality of structural support members each disposed at one of the corners of the support frame and attached to the side rail and to the top rail or the bottom rail to which the side rail is connected at the corresponding corner to transfer torsional loads on the side rails to the top rail and the bottom rail, wherein the side tracks are each mounted to a corresponding one of the side rails of the support frame, wherein the support frame is mounted to the walls of the support structure defining the opening with the top rail anchored to the top wall with a first plurality of fasteners extending through the top rail and into the top wall, the bottom rail anchored to the bottom wall with a second plurality of fasteners extending through the bottom rail and into the bottom wall, and the side rails disposed proximate the corresponding side walls and not secured to the side walls by fasteners extending through the side rails and into the side walls so that the side rails deflect inward toward each other and twist relative to the side walls during loading on the shutter caused by the hurricane without causing loads on the side walls, wherein the side rails deflect inward toward each other and twist relative to the side walls and do not apply twisting and torsion loads to the side walls when loads are applied to the side rails by the side tracks when the shutter is in the unrolled position and the loading caused by the hurricane is applied to the shutter and the side tracks and causes the side tracks to deflect inward toward each other and twist relative to the side walls, and wherein the loading caused by the hurricane is transferred by the structural support members from the side rails to the top and bottom rails and the top and bottom walls.

17. A rolling shutter assembly as defined in claim 16, wherein the side rails of the support frame are against the corresponding side walls of the support structure defining the opening.

18. A rolling shutter assembly as defined in claim 16, wherein one of the side walls defining the opening is a mullion, and wherein one of the side rails of the support frame is disposed against the mullion.

19. A rolling shutter assembly as defined in claim 16, wherein the opening has a mullion extending between and connected to the top wall and the bottom wall defining the opening, wherein the support frame comprises an intermediate vertical rail extending between and connected to the top rail and the bottom rail and positioned to align with the mullion when the support frame is attached to the walls, and wherein the intermediate vertical rail is anchored to the mullion and one of the side tracks of the rolling shutter assembly is anchored to the intermediate vertical rail.

20. A rolling shutter assembly as defined in claim 16, wherein the top and the side rails are hollow tubes, wherein the ends of the top and the side rails are beveled such that the adjoining rails form a mitered corner, and wherein the support frame comprises a plurality of L-shaped unitizing inserts each disposed at one of the corners of the support frame with one leg extending into the end of each of the adjoining rails, and wherein each leg of the L-shaped unitizing insert is connected to the corresponding end of one of the rails to secure the ends of the adjoining rails forming the corner.

21. A rolling shutter assembly as defined in claim 16, wherein the top, the bottom and the side rails are hollow tubes having front, rear, inside and outside walls, wherein inside and rear walls of the side rails do not extend to the ends of the side rails, and wherein the ends of the top and bottom rails abut inner surfaces of the outside walls at the corresponding ends of the side rails when the support frame is assembled.

22. A rolling shutter assembly as defined in claim 16, wherein the bottom wall defining the opening extends outwardly from the structure beyond the opening, wherein the side rails are hollow tubes, and wherein the bottom rail comprises a flat plate having at least one upwardly extending flange at each end extending upwardly into the end of a corresponding one of the side rails to connect the plate to the side rails.

23. A rolling shutter assembly as defined in claim 16, wherein the support frame comprises a lever arm connected to and extending between the side rails of the support frame at a height proximate the bottom of the shutter housing, the assembly comprising: a storm bar header connected to the frame at the height of the lever arm and disposed on the opposite side of the side tracks as the frame and the opening; and a storm bar having one end connected to the storm bar header and the opposite end connected to the bottom wall.

24. A rolling shutter assembly as defined in claim 23, wherein the side rails and the lever arm are hollow tubes, wherein each side rail has an opening through an inner wall of the side rail at the location where the end of the lever arm abuts the side rail, and wherein the support frame comprises a pair of unitizing inserts each inserted into an end of the lever arm and into the opening through the inner wall of the corresponding side rail.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of an opening and a protective panel for covering the opening during a hurricane;

(2) FIG. 2 is a schematic illustration of the opening and the panel of FIG. 1 wherein the panel is fabricated from a rigid material and subjected to negative pressure;

(3) FIG. 3 is a schematic illustration of the opening and the panel of FIG. 1 wherein the panel is fabricated from a flexible material and subjected to negative pressure;

(4) FIG. 4 is a perspective view of an example of a rolling shutter assembly that may be disposed over an opening;

(5) FIG. 5 is a schematic illustration of the opening and rolling shutter assembly of FIG. 4 wherein the side tracks do not retain the ends of the shutter curtain;

(6) FIG. 6 is a schematic illustration of the opening and rolling shutter assembly of FIGS. 4 and 5 subjected to negative pressure;

(7) FIG. 7 is a fragmentary perspective view of a shutter curtain formed by double-wall slats and including retention members for securing the ends of the slats within the side rails of the rolling shutter assembly of FIG. 4;

(8) FIG. 8 is a cross-sectional top view of the shutter curtain of FIG. 7 disposed within a side track of the rolling shutter assembly of FIG. 4;

(9) FIG. 9 is a schematic illustration of the opening and rolling shutter assembly of FIGS. 4, 7 and 8 subjected to negative pressure;

(10) FIG. 10a is a perspective view of the rolling shutter assembly of FIG. 10 and a wide opening divided by a mullion;

(11) FIG. 10 is a perspective view of an embodiment of a rolling shutter assembly with end retention and including a support frame;

(12) FIG. 11 is a schematic illustration of the opening and rolling shutter assembly of FIG. 10 subjected to negative pressure;

(13) FIG. 12 is an exploded view of a corner assembly of the support frame of FIG. 10;

(14) FIG. 13 is a front view of the assembled corner assembly of the support frame of FIG. 12;

(15) FIG. 14 is a front view of an alternative embodiment of a corner assembly of the support frame of FIG. 10;

(16) FIG. 15 is a front view of the lower portion of an alternative embodiment of a support frame having a bottom rail in the form of a plate for attachment to a threshold;

(17) FIG. 16 is a cross-sectional view through line 16-16 of FIG. 15 of the lower portion of the support frame of FIG. 15;

(18) FIG. 17 is a perspective view of an embodiment of a rolling shutter assembly with end retention and including a support frame configured for attachment of a storm bar header;

(19) FIG. 18 is a side view of the rolling shutter assembly of FIG. 17 with the storm bar header attached to the support frame;

(20) FIG. 19 is a perspective view of an embodiment of a rolling shutter assembly with end retention and including an alternative embodiment of a support frame;

(21) FIG. 20 is a partially exploded isometric view of a corner assembly of the support frame of FIG. 19;

(22) FIG. 21 is an isometric view of the corner assembly of the support frame of FIG. 19; and

(23) FIG. 22 is a schematic illustration of the opening and rolling shutter assembly of FIG. 19 subjected to negative pressure.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

(24) 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.

(25) It should also be understood that, unless a term is expressly defined in this patent using the sentence As used herein, the term .sub. 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.

(26) 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.

(27) FIG. 10 illustrates one embodiment of a rolling shutter assemble 130 including a support frame 132 for mounting the rolling shutter about the opening 12 defined by side walls 134, top wall 136 and bottom wall 138. The rolling shutter is similar to the shutter assembly discussed above and may include end retention of the shutter curtain, such as that provided by a shutter curtain formed by slats 80 having extension members 90 and side tracks 100. The support frame 132 includes oppositely disposed side rails 140 connected to top and bottom rails 142, 144, respectively, extending therebetween at opposite ends of the side rails 140. The rails 140-144 are connected in any appropriate manner, such as those described further below, to provide the desired rigidity and structural support, or the support frame 132 may be fabricated from a unitary piece of material. In one embodiment, the rails 140-144 are fabricated as hollow rectangular tubes of extruded aluminum and connected by welding or by insertion of unitizing inserts at the corners to secure the adjoining rails 140-144. To facilitate attachment with the appropriate fasteners, the rails 140-144 include a plurality of openings 146 through their front walls dimensioned to allow the heads of the fasteners to be inserted into the rails 140-144 and through corresponding smaller openings (not shown) to anchor the support frame 132 to the corresponding walls 134-138.

(28) 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.

(29) FIG. 11 is a schematic illustration of the rolling shutter assembly 130 viewed from the bottom wall 138 and showing the reaction of the rolling shutter assembly 130 to the force F.sub.NP created by negative pressure during a hurricane. The side rails 140 are connected to the side walls 134 by fasteners 150, the top rail 142 is connected to the top wall 136 by fasteners 152, and the side tracks 100 are connected to the side rails 140 by fasteners 154. As previously discussed, the slats 80 bow and the ends of the slats 80 move toward the openings of the side tracks 100 as the force F.sub.NP increases. As the slats 80 bow, the extension members 90 are engaged by the fins of the side track 100 to retain the ends of the slats 80 within the side tracks 100. The engagement of the slats 80 by the fins and the front walls of the side tracks 100 generate shear, tension and torsion loading on the fasteners 154 that are transmitted to the side rails 140 by the fasteners 154. The shear loads transmitted to the side rails 140 tend to pull the side rails 140 inwardly and are supported, at least initially, by the side rails 140, the top rail 142 and the bottom rail 144 of the support frame 132. The transmitted tension loads tending to pull the rolling shutter assembly 130 are distributed about the support frame 132 among the fasteners 150, 152 and the fasteners connecting the bottom rail 144 to the bottom wall 138 in a similar manner as the fasteners of the rigid panel 10 discussed above.

(30) 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.

(31) As the force F.sub.NP 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.

(32) 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 F.sub.NP as discussed above, positive pressures cause compression loading against the support frame 132 and, consequently, against the framing elements of the walls 134-138.

(33) 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.

(34) 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. FIGS. 12 and 13 illustrate one method for fabricating a unitized support frame 132. Referring to FIG. 12 which shows the corner of the support frame 132 formed by the top rail 142 and one of the side rails 140, the rails 140, 142 are fabricated from extruded aluminum to form hollow rectangular rails. The ends of the rails 140, 142 are beveled to form a mitered corner of the support frame 132. An L-shaped unitizing insert 160 is configured to be received in the beveled ends of the adjoining rails 140, 142 to provide additional support at the point of connection. The unitizing insert 160 may include openings 162 therethrough on each leg that will align (See FIG. 13) with corresponding openings 164 through the walls of the rails 140, 142 to receive fasteners (not shown) for securing the rails 140, 142 together in a manner that provides structural integrity to the corner of the support frame 132. FIG. 14 illustrates a further alternative embodiment wherein the ends of the rails 140, 142 are connected by a weld 166. If desired, the weld 166 may be used as an alternative fastening mechanism with the unitizing insert 160. Other mechanisms for connecting the rails 140-144 to form the support frame 132 will be apparent to those skilled in the art and are contemplated by the inventor as having use in a rolling shutter assembly in accordance with the present disclosure.

(35) 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.

(36) 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 167, such as those shown in FIG. 10a, cannot be covered by a single rolling shutter 30 due to the planar profile and relatively small cross section of the rolling shutter curtain 50 that make the shutter curtain 50 very flexible and difficult to retain within the side tracks 100. Such wide openings 167 may necessitate the installation of two or more rolling shutters 130 disposed side-by-side and abutting to cover the entire width of the opening 167. In order to support the side tracks 100 disposed within the opening 167, mullions 168 are installed at the necessary positions within the opening 167, and the internal side tracks 100 are attached to the corresponding mullions 168. 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 168. Alternatively, a single support frame 132 may be provided that is dimensioned to surround the entire opening 167 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 168.

(37) 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. FIGS. 15 and 16 illustrate an alternative embodiment of the support frame 132 wherein the bottom rail 144 is replaced by a plate 170 having low profile that presents substantially less obstruction in the entranceway. The bottom ends of the side rails 140 may be straight and parallel to the ground instead of beveled as discussed above, and the plate 170 may have upwardly extending flanges 172 that are inserted into the ends of the side rails 140 and engage the inner surfaces of the side rails 140 to form a unitized structure. During installation, the plate 170 is secured to the threshold by fasteners 174. When the side rails 140 are subjected to sufficient torsion loading to cause deflection of the side rails 140, the deflection transmitted through the flanges 172 tends to rotate the plate 170 in a direction parallel to the threshold. A combination of the rigidity of the plate 170 and the resistance of the fasteners 174 to the resulting shear loads produce the forces necessary to reduce or eliminate the torsion loading on the framing structure of the side walls 134 in a similar manner as described above for the bottom rail 144.

(38) 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. FIG. 17 illustrates the rolling shutter assembly 130 with the support frame 132 configured for attachment of a storm bar header 180 thereto in a manner that allows the support frame 132 to distribute the load applied to a storm bar 182 by the shutter curtain. The support frame 132 includes a horizontal lever arm 184 extending between the side rails 140 and providing additional structural support for the loads generated by the shutter curtain engaging the storm bar 182. The lever arm 184 is located at a level corresponding to the location at which the storm bar header 180 is to be disposed. The lever arm 184 may be connected to side rails 140 by unitizing inserts 186 that are inserted into the ends of the lever arm 184 and through corresponding openings (not shown) through the inner walls of the side rails 140. The lever arm 184 and unitizing inserts 186 may be connected to each other and to the side rails 140 by fasteners, welds or any other appropriate connection mechanism.

(39) FIG. 18 illustrates the rolling shutter assembly 130 with the storm bar header 180 connected to the support frame 132 through the side rail 140 and unitizing insert 186, and with the storm bar 182 attached to the storm bar header 180. Mechanisms for temporarily or permanently connecting the storm bar 182 to the storm bar header 180, as well as connecting the bottom end of the storm bar 182 proximate the bottom of the shutter assembly 130, are well known to those skilled in the art and are contemplated by the inventor as having use in rolling shutter assemblies in accordance with the present disclosure. The ends of the storm bar header 180 are connected to the side rails 140 and corresponding unitizing inserts 186 via fasteners 188 that may pass through the side tracks 100. It should be noted that in the present embodiment the storm bar header 180 need not be directly fastened to the framing structure surrounding the opening as was necessary with previously know rolling shutter assemblies. Further, because the storm bar header 180 is fastened directly to the support frame 132, the storm bar header 180 does not have to extend beyond the edges of the rolling shutter assembly 130. When a load is applied to the storm bar 182 by the shutter curtain and transmitted to the support frame 132 by the storm bar header 180, the additional support provided by the lever arm 184 and unitizing inserts 186 further resists the deflection of the side rails 140 in response to the torsion loads generated by the force F.sub.NP of the negative pressure.

(40) 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.

(41) FIGS. 19-22 illustrate a further alternative embodiment for the support frame 132 having an alternative mechanism for securing the top and bottom rails 142, 144, respectively, to the side rails 140. Referring to FIG. 19, the mitered corner assemblies discussed above are replaced by a configuration in which the walls of the side rails 140 are partially removed so that the ends of the top and bottom rails 142, 144 may be partially nested and received at the ends of the corresponding side rails 140. The adjoining rails are secured to each other by fasteners, adhesive, welding or other appropriate connection mechanism. The corner assemblies may further include angle brackets 190 attached to the adjoining rails at the inside corners thereof for additional structural support.

(42) Referring now to FIGS. 20 and 21, the details of the corner assemblies are illustrated. The inside and rear walls at the ends of the side rails 140 are removed so that the walls do not extend to the ends of the side rails 140 to allow the ends of the top and bottom rails 142, 144 to abut the inside surfaces of the outside walls of the side rails 140. The removed portions of the inside and rear walls may have lengths approximately equal to the width of the top and bottom rails 142, 144 so that the top and bottom rails 142, 144 are approximately flush with the ends of the side rails 140 when the top and bottom rails 142, 144 are nested therein. Holes 192 of the front wall of the side rail 140 may align with corresponding holes 194 of the top rail 142 when the end of the top rail 142 is nested so that fasteners 196 may secure the rails 140, 142. The angle bracket 190 may then be positioned at the inside corner of the corner assembly with holes 198 aligned with corresponding holes 200 of the rails 140, 142 for attachment with fasteners 202, for example. Similar connections of the adjoining rails are made at the other corners of the support frame 132.

(43) As best seen in FIG. 21, in the illustrated embodiment the depth of the side rail 140 and the top rail 142 are the same such that the rear surface of the top rail 142 extends beyond the rear surface of the side rail 140. Consequently, the side rail 140 may be disposed proximate the side wall 134 of the opening 12 similar to the embodiments discussed above, but not against the side wall 134 as shown in FIG. 22. In this configuration, the support frame 132 may be mounted about the opening with the top and bottom rails 142, 144 against and secured to the top and bottom walls 136, 138, respectively, of the opening 12. At the same time, the side rails 140 are proximate to but spaced from the side walls 134 of the opening 12, and are not necessarily secured to the side walls 134. When the negative pressure F.sub.NP is applied to the cover, the force is taken up by the top and bottom rails 142, 144 and transferred to the top and bottom walls 136, 138, and the shear, torsion and tension loads on the framing elements of the side walls 134 are significantly reduced or eliminated. Depending on the magnitude of the negative pressure F.sub.NP and the properties of the support frame 132, the side rails may temporarily deflect and twist under the loading on the side tracks 100 without causing twisting and torsion loads on the framing elements of the side walls 134. Of course, depending on the installation, the side rails 140 may still be secured to the side walls 134 in a similar manner as described above. Additionally, the top and bottom rails 142, 144 may have smaller depths so that the rear surfaces of the top and bottom rails 142, 144 are flush with the rear surfaces of the side rails 140, with the rear surfaces of the side rails 140 against the corresponding side walls 134 of the opening 12. In this configuration, the side rails 140 may or may not be fastened to the side walls 134.

(44) 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.