Abstract:
The present invention is an exterior window covering or exterior shutter that is comprised of layers of materials to form a sandwich. The sandwich material has a layer of polycarbonate material. An embodiment of the sandwich material is comprised completely of synthetic materials that are resistant to the adverse effects of sunlight, humidity, rain, heat and wind. The polycarbonate material yields an exterior shutter that retards flying objects and withstands substantial stresses from wind loads.

Description:
FIELD OF THE INVENTION 
     This invention relates to exterior window coverings, such as shutters. 
     BACKGROUND OF THE INVENTION 
     Exterior window coverings, such as window shutters, have been used for many years. Window shutters are positioned over glass windowpanes to protect the glass windowpanes from flying objects that can damage, or break, the glass, and enter the building. Window shutters may be used to secure a building against break-ins, and may be used to block sunlight from entering the building through the windowpane. The window covering, or shutter, may be pivoted away from the windowpane to lie flat against the building. When the shutter is pivoted away from the windowpane, it enhances the beauty and appearance of the building. 
     There is a need to provide a window covering which will pass missile tests that have been established by testing agencies to judge a material&#39;s ability to withstand and retard flying objects. The window covering should also be able to perform successfully in commonly used wind load tests, which judge a material&#39;s ability to withstand stresses from continuous wind loads. 
     There is also a need for an exterior window shutter that will not require substantial maintenance in adverse conditions. In particular, there is a need for a window shutter which will remain relatively maintenance free in hostile environmental conditions, such as the tropics and subtropics, where direct sunlight exposes the window covering to substantial heat, humidity, and ultraviolet rays from the sun. Further, these environments are typically near salt water, and the salt air contributes to the deterioration of building materials. Still further, these tropical and subtropical environments may experience frequent hurricanes, which means that the substantially maintenance free window covering is exposed to high winds and wind driven water. 
     SUMMARY OF THE INVENTION 
     The present invention is an exterior window covering or exterior shutter that is comprised of materials to form a sandwich. The sandwich material has a layer of polycarbonate material. The preferred embodiment of the sandwich material is comprised completely of synthetic materials that are resistant to the adverse effects of sunlight, humidity, rain and wind. The polycarbonate material yields an exterior shutter that retards flying objects and will pass a missile test. The resulting shutter will also withstand substantial stresses from wind loads, so as to perform satisfactorily in wind load tests. When all layers of the sandwich material that forms the exterior window covering are formed of synthetic material, the resulting window covering is substantially maintenance free. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevation of one style of the exterior shutter of the present invention. 
         FIG. 2  is an elevation of the opposite side of the shutter of  FIG. 1 . 
         FIG. 3  is a front elevation of another style of the exterior shutter of the present invention. 
         FIG. 4  is an elevation of another style of the exterior shutter of the present invention. 
         FIG. 5  is a partial perspective of the exterior shutter of the present invention of the style shown in  FIGS. 1 and 2 . 
         FIG. 6  is a partial perspective of the exterior shutter of the present invention of the style shown in  FIGS. 3 and 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The exterior window covering of the present invention is formed of a sandwich material. A first plane of material  2  forms one layer of the sandwich, and a second plane of material forms a second layer  4  of the sandwich. In most embodiments, the sandwich material will be rectangular in shape, since most windows are rectangular in shape; however, the invention is not limited to shutters that are rectangular in shape. In the most typical application, the first plane of material and the second plane of material will each have substantially the same length as the window to be covered and will be approximately one-half of the width of the window to be covered. The shutters are used in pairs to cover the window. 
     In the preferred embodiment, the first plane of material and the second plane of material are a synthetic material that will retard the adverse effects of wind, water, heat, cold, and ultraviolet rays. A preferred material from which to form the first plane and the second plane is polyvinyl chloride, and particularly, foam polyvinyl chloride. 
     Between the first plane of material and the second plane of material is a core  6  that is formed of polycarbonate. Polycarbonate is critical to the invention. The resulting shutter of the invention will retard flying objects and perform satisfactorily in missile tests and wind load tests. Polycarbonate is sufficiently resistant to stresses created by wind loads, so as to be resistant to breaking, and at the same time is sufficiently resistant to piercing by flying objects, thereby yielding a window covering which will pass the required tests. The core formed of polycarbonate substantially matches the perimeter dimensions of the first plane and the second plane. 
     The sandwich material is formed by connecting the first plane, the core of polycarbonate, and the second plane. It is preferred that the first plane, the core of polycarbonate and the second plane are connected by an adhesive. The adhesive may be a combination of 3M® adhesive and PVC cement. Other means for connecting the materials, such as fasteners, may be used; however, the use of an adhesive yields a sandwich material which is uniformly strong at all surfaces of the sandwich material. 
     One or more stiles  8  are used to add further strength to the shutter. In the preferred embodiment, a first stile is attached along the edge of the shutter that represents the length of the shutter, and an additional stile is attached along the opposite side of the shutter. The stile is preferred to be generally U-shaped, and comprised of three sides. The stile may be formed of metal, such as aluminum, which is corrosion resistant. A first side  10  of the stile is generally parallel to a second side  12  of the stile. The first side contacts the first plane of material and the second side of the stile contacts the second plane of material. A third side  14  of the stile connects the first side and second side of the stile, and is generally perpendicular to the first side and the second, so that the stile is U-shaped. The third side of the stile will contact the edge of the sandwich material as shown in  FIGS. 5 and 6 . It is preferred that the first material and the second material are formed with an indention, or is of reduced dimension, where the stile contacts the first plane of material and the second plane of material, so that the stile does not extend beyond the outer surface of the first plane of material or second plane of material, where the stile contacts the first plane of material and the second plane of material. 
     As shown in the drawing figures, the first plane of material is of reduced dimension on a portion of the outer surface thereof. As shown in  FIG. 3 , the first plane of material has a multiplicity of grooves  16  that are formed generally parallel to each other. Similarly, the second plane of material is of reduced dimension along portions thereof, with a multiplicity of generally parallel grooves formed in an exterior surface of the second plane of material. 
     As shown in  FIG. 1 , the first plane of material is of reduced dimension so that panels  18  are formed within the shutter. The reduced dimension should be on an exterior surface of the first plane of material. Similarly, the exterior surface of the second plane of material is of reduced dimension at portions of the surface thereof, so that panels are formed therein. As shown in  FIG. 1 , additional materials may be added to the sandwich material to enhance the structure and/or appearance of the device. The additional materials may be polyvinyl chloride. 
     The first plane of material and the second plane of material may be formed in varying materials as desired, such as white, dark green, or black, or any other color desired. Alternatively, the shutter may be painted to any color desired. 
     The shutters are attached to a building, or to a window frame. The shutters may be attached by pivotal means, such as hinges, so that the shutter may be positioned over a window, or away from a window, as desired.