Patent Publication Number: US-2009235602-A1

Title: Strengthened shutter system

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to shutter systems for covering openings in walls of buildings and, more particularly, to a strengthened retractable/deployable shutter system and barrier assembly for use in connection therewith that utilizes a combination of interlocking slats and interlocking connecting members having recesses to assist in retaining the slats in associated guide rails when displacement forces are exerted upon the slats. 
     BACKGROUND OF THE INVENTION 
     Shutter systems are well known. Such systems are typically used on an as-needed basis to cover and protect windows, doors, and other openings in buildings from flying debris and other displacement forces that result from strong storms, such as severe thunderstorms, hurricanes, tropical storms, typhoons, and tropical cyclones. Such systems may also be used on a more regular basis (e.g., daily) to provide privacy, noise reduction, and security or intrusion resistance. 
     Basic shutter systems include a barrier assembly made up of corrugated steel or aluminum alloy panels that are fastened over the wall openings using threaded bolts that screw into anchors recessed in the walls of the building. Other basic systems also use corrugated panels, but instead of recessed anchors, such systems use rails that are secured to the building above and below the opening. The panels are inserted along the rails and are secured to the rails with bolts and wing nuts. 
     While storm panels are useful in protecting the building&#39;s openings, they have certain disadvantages. For example, steel panels are relatively heavy, weighing approximately two pounds per square foot. Thus, such panels become difficult to install on a two or three story dwelling, particularly when the homeowner must carry each panel necessary to cover the upper story windows up a ladder and onto a roof. Making the upper story installation even more difficult is the common use of wavy, Spanish tile roofs on many homes in geographical areas that are more prone to be in the paths of hurricanes or other strong storms. 
     Other more sophisticated storm shutter systems are also commercially available. One such system is referred to as an accordion shutter system. In an accordion shutter system, rails are installed above and below the wall opening, and a flexible, corrugated panel is permanently installed just outside each vertical end of the opening such that the panels, when deployed, can slide in the track created by the rails. When not in use, the panels are in a collapsed or compressed state and reside adjacent the vertical ends of the opening. To use, the user manually pulls or deploys each panel toward the center of the opening and locks the two panels together with a small padlock or other locking mechanism to keep them in place. When the storm has passed or use is otherwise no longer necessary or desired, the lock is removed and the user manually pushes or retracts the panels into their collapsed positions adjacent the vertical ends of the opening. Since the accordion panels are permanently installed, they need not be physically carried to and from their intended location before and after use. 
     Another more sophisticated shutter system is commonly referred to as a roller system or a rolling shutter system. In this system, the panels and anchors or rails of basic and accordion systems are replaced with a different barrier assembly made up of a series of interlocking steel or aluminum alloy slats that are wound around a motorized roller tube or reel. The roller tube resides in a housing that is mounted to or within the building just above the opening to be protected. Guide tracks are also mounted on each vertical sidewall of the opening to be covered to guide the movement of the slats during deployment and retraction. 
     The motor of the rolling shutter system is electrically controlled and deploys the slats to cover the building&#39;s opening upon activation thereof. The deployment or lowering of the rolling shutter is based on the free fall of the interlocked slats primarily from the force of gravity while the roller tube rotates in one direction. Subsequent activation of the motor causes the motor to rotate the roller tube in an opposite direction to retract the slats and restore them on the roller tube. A motorized roller and its associated housing are permanently installed above whichever opening(s) are to be covered by the system. Dependable operation of the rolling shutter system relies on the ability of the slats to freely travel in the guide tracks without obstruction from pins, stems, or any other integrated components of the tracks. 
     While rolling shutter systems are very convenient forms of storm protection and security, they have their limitations. For example, the exertion of sufficiently strong displacement forces against the slats can cause the slats to deflect or bow excessively and thereby dislodge from the guide tracks, exposing the wall opening to flying debris or an intruder. 
     Various approaches have been proposed in order to try to prevent such dislodgement of the slats. One such approach is disclosed in U.S. Pat. No. 5,839,493 issued to Quasius. Quasius describes a rolling shutter and retention assembly in which stop elements are inserted into the ends of the shutter slats and the guide tracks include angled retention surfaces. When the slats are bowed as a result of displacement forces, the stop elements (e.g., screws or nails) engage the retention surfaces of the guide tracks to prevent or substantially impede dislodgement of the slats. While the Quasius system includes the use of a slat retention stop element  54 , it requires a reinforcement bar  26  to be press fit within the corresponding slat to which the stop member is to be connected, and the stop member then driven into an aperture defined by the reinforcement bar. This arrangement does not permit for a particularly secure connection between the stop member  54  and the aperture in the reinforcement bar  26 , which can lead to weakness and/or total failure of the retention arrangement. In addition, the stop elements of the Quasius system are made of steel and, therefore, do not recover from bending that may result from the application of strong displacement forces against the slats. The stop elements&#39; failure to recover from bending could produce an obstruction in the guide tracks, thereby negatively impacting the movement of the slats during subsequent attempted normal operation of the system. To avoid such obstruction, the stop elements may require replacement, which, if not performed properly and quickly, could reduce the usefulness of the system. 
     Another slat dislodgement prevention approach is disclosed in U.S. Pat. No. 5,657,805 issued to Magro. The Magro patent discloses the use of endlocks  48 , which are fastened to the ends of the slats using external fasteners, which, again, is a time consuming exercise and, consequently, adds unnecessarily to the cost of manufacture. Furthermore, the fasteners can loosen over time due to vibrations associated with deployment and retraction of the system as well as wind and other external forces. 
     Another slat retention apparatus is disclosed in U.S. Pat. No. 5,253,694 to Bernardo. The Bernardo apparatus discloses a slat end retainer which is attached via fasteners to the ends of one or more slats of a rolling shutter system. These end retainers are, like the retainer of Magro, attached using manual fasteners (3 screws or rivets), which adds to the cost of manufacture and which can loosen over time, defeating the purpose of the invention. 
     Another slat dislodgement prevention approach is disclosed in German Patent Application Publication No. DE 2709029A1. Such publication describes a rolling shutter that includes a guide track having one or more stems extending perpendicularly from respective shanks of the track. The slats of the shutter system have matching recesses to accommodate the extending stem(s) while leaving room for play. While the system described in the German publication provides a mechanism for reducing the likelihood of slat dislodgement without the need for stop ends to be inserted in the slats, such system requires the slats to operate integrally with the perpendicularly oriented guide rail stems. However, the guide rail may not be perfectly vertical due to variations in normal architectural tolerances in the building to which the guide rail is attached. As a result, the guide rail stem may slightly obstruct the deployment of the slats, particularly when the shutter system is used on a daily basis for, e.g., security and privacy reasons. 
     Therefore, a need exists for a shutter system and barrier assembly for use in connection therewith that substantially reduces the likelihood of slat dislodgement in the presence of severe displacement forces without requiring the use of external fasteners, which can work loose over time and which are time consuming and labor intensive to install. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is cross-sectional side elevational view of an installed shutter system of the type in connection with which the instant invention is adapted to be employed, installed in a building in a partially deployed configuration to cover an opening in a building. 
         FIG. 2A  is a right perspective view of a slat end retention plug in accordance with this invention. 
         FIG. 2B  is a left perspective view of the slat end retention plug shown in  FIG. 2A . 
         FIG. 2C  is a right perspective exploded view of the slat end retention plug shown in  FIG. 2A , and the slat before the slat end retention plug and the slat are plugged together. 
         FIGS. 3 through 6  are a top cross-sectional plan view of alternative embodiments of the invention taken along lines  3  through  6  of  FIG. 1 . 
         FIGS. 7 through 10  show the slot retention plug of the instant invention fastened to shutter slats using a variety of punch techniques. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Generally, the present invention is an improvement to a rolling shutter system/barrier assembly for use in connection therewith for covering an opening in wall of a building. The shutter system includes a mounting assembly and a retractable/deployable barrier assembly. The mounting assembly includes at least one pair of guide tracks that are mountable to the wall of the building on opposing sides of the opening. Each guide track includes inner surfaces that define a guide channel. Two of the track&#39;s inner surfaces oppose one another and at least one of the two, opposing, inner surfaces includes one or more protruding members that extend into the guide channel. 
     The shutter assembly includes a series of interlocking slats. The slats are constrained for vertical movement within the guide rails by a pair of slat retention plugs  10 , one mounted at each of the left and right ends of one or more of slats  20 . Each plug  10  is sized and shaped to fit into an end of one of the slats  20  and within channel  24  of guide rails  22 . Plugs  10  include a tapered section  12  and an enlarged end section  14 , forming a shoulder  16  at the intersection thereof. Each of the guide rails  22  define projecting members  26 , which protrude from one or both of the interior sidewalls  28 A,  28 B of guide tracks  22  so as to occupy a portion of channels  24 . 
     Each plug  10  has a central portion  18  having an outer peripheral surface shape which corresponds generally to the interior surface shape of slat  20 . An enlarged stop member  19  is formed at the distal end of plug  10 , and forms a shoulder  21 . 
     During assembly of the slats  20  and plugs  10 , a plug  10  is inserted into the open end  23  of slat  20 , as shown in  FIGS. 2C . In order to securely attach the plugs  10  to the slats  20  and render the plug non-removable therefrom, a punch press or other mechanism is employed to create in part one or more attachment tabs  30 , as shown in  FIGS. 2C through 10 . Tabs  30  are created by applying pressure over specified areas of one or more of the slats  20  in the barrier. The tabs  30  are created by tearing/cutting away a portion of the material of slat  20  corresponding to the tab or tabs being created, where the tabs  30  nest against or mate with a portion of tapered section  12  of plugs  10 . The tabs  30  can also be a stamped cutout formed in a wall of the slat  20 . Ends  31  of tabs  30  engage shoulders  16  of plugs  10  to prevent removal of plugs  10  from the slats  20 . 
     By providing a shutter system and barrier assembly in this manner, the present invention reduces the likelihood of slat dislodgement in the presence of strong displacement forces, such as wind forces and projectile impact forces that result from strong tropical storms, typhoons or hurricanes. With the present invention, fabrication of the slats and the guide tracks can proceed using conventional fabrication processes. For example, the guide tracks and slats of the present invention, including the stop members  26  formed in the channels  24  of guide rails  22 , may be fabricated using the same extrusion processes that are used to make existing guide tracks and slats. 
     The present invention can be more fully understood with reference to  FIGS. 1-10 , in which like reference numerals designate like items.  FIG. 1  is a cut-away side elevational view of an installed shutter system  100  in a partially deployed configuration to cover an opening  101  in a building. The depicted shutter system  100  includes a retractable and deployable barrier assembly, a mounting/housing assembly  102 , and a motorized roller  107  (shown in phantom in  FIG. 1 ). The barrier assembly preferably includes a series of interlocking horizontal slats  20  that deploy from and retract into, as applicable, the roller  107  and/or its associated housing  108 . When deployed, the slats  20  cover the opening  101  in the wall  103  of the building such that the inside surfaces of the slats  20 , which together define an inside surface of the barrier assembly, are proximate the opening  101  and the outside surfaces of the slats  20 , which together define an outside surface of the barrier assembly, face the outdoors and are positioned to receive any externally-generated displacement forces that may be exerted against the barrier assembly. The motorized roller  107  is constructed in accordance with conventional techniques to retain the slats  20  in a rolled configuration until deployment is desired and to deploy the slats  20  upon activation by a user such that the slats  20  cover the opening  101  in the wall  103  to which the motor housing  108  is mounted. 
     Each of the slats  20  is preferably fabricated in a conventional manner from high strength aluminum alloy (e.g., 6063-T5 or 6063-T6 extruded aluminum alloy manufactured by Aluminio Dominicano of Santo Domingo, Dominican Republic or various other manufacturers), steel, high strength plexiglass, or any other material capable of withstanding a desired level of displacement forces (e.g., those associated with wind speeds up to approximately 155 miles per hour). When deployed, the series of slats  20  have a length larger than the wall opening  101  that the slats  20  are intended to shield to prevent, or at least substantially impede, any projectiles or other displacement forces from entering the opening  101 . 
     The mounting assembly preferably comprises at least one pair of guide tracks  22  that are mountable to opposing sides of the wall opening  101 . Each guide track  22  is preferably fabricated from high strength aluminum alloy (e.g., 6063-T5 or 6063-T6 extruded aluminum alloy) using conventional extrusion processes. During installation, each guide track  110  is mounted to the wall  103  using appropriate conventional fasteners (e.g., TAPCON concrete screws when the guide tracks  22  are secured to a concrete block wall  103 ). The guide tracks  22 , the slats  20  of the shutter system  100  are described in more detail with respect to  FIGS. 3-10 . 
       FIGS. 3-4  are partial detailed cross-sectional top views of left and right guide tracks  22 , and a slat  105  of the shutter system  100  of  FIG. 1  in accordance with a first embodiment of the present invention. As shown, the guide track  22  includes inner surfaces  28 A- 28 B that together defines opposing sidewalls of a guide channel  24  of track  22 . With such construction, the guide channel  24  has an open end  27  that permits the slats  20  to extend out of the track  22  and across the wall opening  101 . Thus, the guide track  22  functions in concert with plugs  10  to maintain the slats  20  of the barrier assembly in a desired position relative to the wall opening  101 . 
     In addition to assisting in defining the guide track&#39;s guide channel  24 , one or both opposing inner surfaces  28 A,  28 B of the guide track  22  include one or more protruding stop members  26  (two shown, although only one is necessary to accomplish the purpose of strengthening the shutter assembly against external forces (i.e. those imposed from the top of the drawing in  FIG. 4 )). In the event only one stop member  26  is used in such an application (i.e. to guard against externally applied loading), the lower stop member  26  in  FIGS. 3 and 4  may be deleted. Each stop member  26  extends into the guide channel  24 . In the embodiment shown in  FIGS. 3 and 4 , stop members  26  extend into channel  24  essentially perpendicularly to sidewalls  28 A,  28 B. In the embodiment shown in  FIGS. 5 and 6 , all structural configurations remain the same, with the exception that the stop members  261  angle away from the guide channel&#39;s open end  27 . The angle at which the stop member(s)  26  extend into the track&#39;s guide channel  24  may be any angle in the range of about 30 degrees to about 89 degrees, but preferably comprise an angle in the range of about 45 degrees to about 75 degrees. The angle at which the stop member(s)  26  extend into the guide channel  24  is preferably determined by measuring the angle (θ) formed between the inner surface  28 A,  28 B of the guide track  22  from which the stop member  26  extends and an inner, angled surface  27  of the stop member  26 . 
     The amount that the protruding member  26  extends into the guide track&#39;s channel  24  depends on a variety of factors, including, without limitation, the size and shape of enlarged end  19 , the location of the member  26  in the channel, the amount of slat deflection permitted prior to engagement between shoulder  21  and stop member  26 , and characteristics of the materials, channel width, and building height. In a preferred embodiment, the stop member  26  has a length in the range of approximately ¼ inches to ½ inches (approximately 6.35 millimeters to 12.7 millimeters) and extends into the guide channel  24  in the range of approximately 3/16 inches to 7/16 inches (approximately 4.7 millimeters to approximately 11.2 millimeters). 
     As can be seen in  FIGS. 4 and 6 , when an external load L (such as wind loading, a projectile or an intruder) is imposed upon slats  20 , the slats deflect. This deflection causes the ends of slats  20 , and consequently the plugs  10  which are securely fastened thereto, to translate toward the building opening  101 . This in turn causes shoulders  21  of plugs  10  to engage the stop members  26 ,  26   1  (as the case may be), thereby prohibiting slats  20  from deflecting any further. This, in turn, prevents slats  20  from being dislodged from channels  24 . The same would occur as to forces L exerted on the interior (building) side of slats  20  so long as the lower stop members  26  shown in  FIGS. 4 and 6  are present. 
     As described above, the present invention encompasses a shutter system and associated barrier assembly for use in protecting building wall openings from damage resulting from exertion of large displacement forces, such as wind forces exerted during thunderstorms, tropical storms, hurricanes, tornados or other events. The shutter system and barrier assembly of the present invention reduce the likelihood that strong displacement forces exerted against the slats and connecting members of the barrier assembly will dislodge the slats from the mounting assembly, without requiring the fabrication complexities of some prior art slat dislodgement mitigation solutions. With the present invention, fabrication of slats of the barrier assembly and guide tracks of the shutter system&#39;s mounting assembly can proceed using conventional fabrication processes. In addition, by incorporating stop members  26  and plugs  10 , the present invention provides cost effective and efficient slat dislodgement protection while mitigating the likelihood of slat obstruction during deployment and retraction of the slats. 
     In the foregoing specification, the present invention has been described with reference to specific embodiments. However, one of ordinary skill in the art will appreciate that various modifications and changes may be made without departing from the spirit and scope of the present invention as set forth in the appended claims. For example, various combinations of stop members  26 ,  26   1  and corresponding mating surfaces on plug  10 , such as shoulder  21 , are contemplated to be within the scope of my invention. For instance, the guide track may be fabricated to include multiple stop members and the plugs may be fabricated to include multiple corresponding shoulders or recesses to achieve a desired reduction in the likelihood of slat dislodgement. In addition, plugs  10  may be incorporated in only some, but not all, of the slats  20  (e.g., only in those slats that are centrally located over the wall opening  101  when the barrier assembly is fully deployed) depending on a desired amount of slat dislodgement reduction or a determination of which slats are more likely to be dislodged when the barrier assembly is fully deployed and displacement forces are applied. Further, the roller  107  that retains the slats  20  of the barrier assembly of  FIG. 1  may be spring-loaded instead of motorized to facilitate manual deployment and retraction of the barrier assembly. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. 
     Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments of the present invention. However, the benefits, advantages, solutions to problems, and any element(s) that may cause or result in such benefits, advantages, or solutions to become more pronounced are not to be construed as a critical, required, or essential feature or element of any or all of the claims. As used herein and in the appended claims, the terms “comprises,∞ “comprising” or any other variation thereof is intended to refer to a non-exclusive inclusion, such that a process, method, apparatus, or article of manufacture that comprises a list of elements does not include only those elements in the list, but may include other elements not expressly listed or inherent to such process, method, apparatus, or article of manufacture.