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FIELD OF THE INVENTION  
       [0001]    The invention relates to a window insert, and more particularly to a removable and selectively interchangable screen or storm window, claiming priority from provisional patent application 60/407,916, dated Sep. 3, 2002 and entitled COMPRESSIBLE INSERT ASSEMBLY. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    Storm window have been utilized for many years in an effort to reduce drafts and the substantial loss of energy, heat or cooling, through inefficient windows. Such storm windows are commonly formed from a transparent shield, such as glass or plexiglass, which is held in places with a frame, commonly formed of aluminum. The sotrm window is held in place with fasteners such as screws or nails that damage the existing frame, allowing dirt and moisture to penetrate the protective paint barrier.  
           [0003]    Typical storm windows require considerable labor and generally must be purchased to size. The frames may be adjustable in size, but generally to a small degree, e.g. within an inch. Thus, the installer must take measurements, go obtain the storm windows. Match each window to the proper sill and begin installation. Stores must carry a wide variety of sizes to fit all the different sized widows for which a customer may wish to purchase a storm. This uses up floor space and accordingly increases the price charged.  
           [0004]    Should the user wish to change from a storm window to a screen, perhaps in the Spring or Summertime, the user either needs to purchase a multi-paneled storm window or switch storms. Such convenience further adds to the complexity and expense or typical storm windows.  
           [0005]    What is needed is a storm window that can be cut to size an assembled at the job site to eliminate the need for pre-measuring and minimize floor space needed to display the storms at the store. As a further measure to reduce needed floor space, the window pane should be flexible, bendable perhaps to the point of being creasable such that it may be packaged as a small roll. The storm window should be easy to construct and easy to insert into a window frame to minimize time and effort. Desirably, the storm window should be held in place without the need for fasteners that penetrate into the window frame, avoiding destruction and introducing deterioration to the window frame. The frame should allow for tensioning or tightening of the sheet, e.g. window pane, to remove any bends or creases and provide an even smooth surface when installed. The frame should secure the sheet against slippage that could cause later wrinkles. Ideally, the window would allow for easy changing of a non-porous pane with a screen the reverse to allow the user to determine whether or not they desire fresh air. As a further desired feature, the sheet shoul be strong, such that it is not easily broken or shattered.  
         SUMMARY OF THE INVENTION  
         [0006]    The present window covering is provided with an insert, a first sheet an a sealer. The insert includes a top rail and a bottom rail joined to at least two side rails. The insert has a front face a back face and an outer periphery. The first sheet spans the front face and joins to each of the rails. Opposing rails are rotatable in opposite directions to tension the sheet. The opposing rails are lockable to prevent loosening of the sheet. The sealer circumscribes an outer periphery of the insert.  
           [0007]    The method of making a window covering includes the steps of joining a top rail, a bottom rail and at least to side rails to form an insert; securing a first sheet to the insert; tensioning the sheet; and placing the insert into a window frame.  
           [0008]    The invention as described is an insert for placement into an existing window opening. The insert is a frame sized to fit within an existing window opening so that the frame will fit closely against the frame and seal against the frame. The frame is covered on at least one side with a sheet that restricts or prevents the entry of an environmental agent.  
           [0009]    In one form of the invention, the sheet is a transparent sheet of a polymer that allows the transmission of light, but, prevents the transmission of air. Here the insert is used to close the window opening or to add at least one layer of “dead” air as an insulative barrier for the structure. This form may be interchanged into other forms.  
           [0010]    For instance, another form of the invention has the sheet perforated, such as, screening and allows the transmission of both air and light. Here the insert will allow light and breezes to pass through the window while preventing the entry of insects and other animals.  
           [0011]    In a third form, the sheet may be colored to provide partially to completely blocked light and to provide tinting in the case of partial light blockage.  
           [0012]    In yet another form, multiple sheets may be used to form multiple air pockets for insulation value. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a perspective view of the insert illustrating the insert proximate a window frame assembly;  
         [0014]    [0014]FIG. 2 is partial cut-away view of the frame of the insert showing the construction of the insert in the area of the frame;  
         [0015]    [0015]FIG. 3 is partial cut-away view showing the construction of the corners of the frame of the insert; and  
         [0016]    [0016]FIG. 4 is a plan view of an insert showing the triangulating braces. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    The frame insert assembly  10  has an insert  12  for fitment within a frame  14 . The frame  14  may be, typically, an existing window mounted in an existing wall of a building. The frame  14  is conventional in construction and may include trim molding  20  mounted to the jams  22  of the frame  14 . The frame  14  may have a movable sash  24  or perhaps, as illustrated, a double hung window having two movable sashes  24 . As is conventional, the frame  14  has a head jam  22 . 1 , two side jams  22 . 2  and a base jam or stool  22 . 3 .  
         [0018]    The insert  12  has a frame  30  with rails  32 , including side rails  32 . 1 , a top rail  32 . 2 , and a bottom rail  32 . 3 . At the junction of any two rails  32  there is a corner  34 . The corner  34  serves the function of connecting and locating a pair of adjacent rails  32 . Each rail  32  is attached at each respective end to a corner  34  using a suitable mechanism. The respective rails  32  and corners  34  should have substantially the same outer dimension so that the junction between a rail  32  and a corner  34  is fairly smooth and not stepped at the juncture of the rail  32  and the corner  34 .  
         [0019]    The rails  32  and corners  34  may be constructed from any suitable material having the properties of having sufficient stiffness or rigidity without becoming brittle, being relatively inexpensive, and being workable. Suitable materials would include various plastics or polymers, metals, and wood. The rails  32  and corners  34  may be of any suitable cross-sectional shape such as round or square tube, bar stock, or a decorative shape. The preferred material for construction of the rails  32  and corners  34  is PVC or CPVC having a round cross section which is readily available from numerous well known suppliers.  
         [0020]    In a preferred mode, the rails  32  and corners  34  may be constructed of PVC or CPVC pipe with the corners  34  being 90 degree elbows. Additionally with PVC piping, the outside diameter of ½ inch pipe is approximately {fraction (3/4)} inch, which will provide an interference fit of {fraction (1/2)} inch pipe into {fraction (3/4)} inch pipe. This mode fortuitously allows the use of CPVC {fraction (1/2)} inch, inside diameter, elbows as corners  34  and {fraction (1/2)} inch inside diameter PVC pipe as rails  32 , the corners  34  and rails  32  thence having substantially the same outside diameter. Similar advantages are found with materials of other sizes as well.  
         [0021]    The joining of the rails  32  to the corners  34  may be accomplished with the use of a tenon  36 . The tenon  36  is preferrably a short piece of {fraction (1/2)} inch pipe that will slide into both the rail  32  and the corner  34 . Preferably, the tenon  36  is fixedly joined to the corner  34  so that the tenon  36  cannot be inadvertently displaced destroying the integrity of the joint. While the tenons  36  may be joined to the corners  34  using any suitable mechanism such as gluing, fusing, or mechanical fasteners, it is preferred that the tenons  36  be joined to the corners  34  using the solvent or glue that is intended for the type of pipe being used for the corners  34  or rails  32 . Such solvents or glues are readily available from the same vendors as the PVC or CPVC pipe. Above is illustrated, how to make the corners  34  from readily available pre-existing parts, but one skilled in the art knows that the corner  34  may be formed integrally with associates tenons  36  in a mold or by other processes.  
         [0022]    A simple rectangle of rails  32  an corners  34  is often adequate to form the insert  12  for many applications. However, additional strength, beauty and/or insulation value may be acquired using additional bracing to stiffen the rails  32 . The additional bracing may be provided, for example, with triangulators  33  which join a side rail  33 . 1  with an adjacent top rail  33 . 2  or bottom rail  32 . 3 . The triangulators  33  may be additional sections of PVC pipe of the same material as the rails  32  and serve to prevent the bending of the rails  32  when tensioned and placed into a frame  14 . Triangulators  33  may provide additional insulation value where a plurality of sheets  50  are joined to the insert  12  with the trangulators  33  disposed therebetween. The triangulators  33  reduce airflow within the airspaces, e.g., the triangulators  33  block and restrict the air flow, while creating air pockets within the triangulators  33 .  
         [0023]    A sheet  50  is attached using a suitable mechanism to one face of the rails  32  and extends across the opening formed by the rails  32  and corners  34 . The sheet  50  provides the function of closing off the insert separating the inside from the outside. The sheet  50  may be attached to the rails  32  and corners  34  using any suitable mechanism such as glue or adhesives, mechanical fasteners such as staples, kerfing the rails  32  and corners  34  and attaching the sheet using a spline to hold the sheet  50  in the kerf. It is preferred, however, that the sheet  50  be attached to the rails  32  using an adhesive.  
         [0024]    The sheet  50  may be any suitable separator that provides the intended separation of elements. In one example the sheet  50  is a transparent film that allows the passage of light and prevents airflow. In this use the insert  12  will function as a storm window in an existing window to increase the insulative properties of the window. In another example, the sheet  50  is a screen that allows airflow while preventing the entry of insects and other undesirable objects. Opaque films may be used to block light and air, while translucent films may be used to block air and allow partial light. One optional sheet  50  contemplated within the current invention is the joinder of pieces of translucent films of varying color in a pattern, such as a stained glass window, to form a mosaic. A preferred sheet  50  is sold by Phifer Wire Products, Inc. P.O. Box 1700 Tuscaloosa, Ala. 35403 under the trademark PETSCREEN. Such sheet  50  secured to the insert  12  in accordance with the teaching herein, remained unbroken when an adult of  200  plus pounds intentionally ran directly into the sheet  50 , demonstrating the resiliency of the present storm window.  
         [0025]    A resilient sealer  60  may be attached about the outer periphery of the insert  12 , providing a seal between the insert  12  and the frame  14 . The resilient sealer  60  may be a strip of an expanded polymer attached to the perimeter formed by the rails  32  and the corners  34 . The insulating tape forming the sealer  60  may be of any suitable width, and is commonly {fraction (3/4)} inch wide, similarly, the insulating tape forming the sealer  60  may be of any suitable thickness and is commonly {fraction (1/2)} inch thick. It has been found that insulating foam commonly sold for insulating windows performs quite well. An additional advantage is that such insulating tape is readily available in pre-cut to suitable lengths and is faced on one side with a pressure sensitive adhesive to allow the sealer  60  to be attached to the perimeter of the insert  12 . A suitable product is available from W. J. Dennis an Company (Elgin, Ill.). Alternatively, insulative pipe covering may be used to provide the seal.  
         [0026]    The fabrication of the insert  12  preferably involves two separate processes. In the initial fabrication, an assembly is fabricated and packaged to produce the individual kits. Each kit is intended to for use in one window frame  14 . With the fabrication, the corners  34  preformed with integral tenons  36  or are assembled by inserting and adhering the tenons  36  into the respective corners  34 . There are four completed corners  34  being prepared for each assembly. A sheet  50  of suitable size and material is included with the kit and a suitable length of the resilient sealer  60  is included in the kit along with the necessary fasteners to connect the rails  32  to the corners  34 . The fasteners may be any suitable fastener and are typically screws  38 , the use of which will be explained later, and the adhesive which may be used to attach the sheet  50  to the rails  32 . Each kit unit may then be packaged for distribution.  
         [0027]    The second phase of fabrication involves construction and insertion of the insert  12 . Prior to the actual use of the insert  12 , the insert  12  must be sized and fitted to the actual frame  14 . A user will measure the height and width of the selected frame  14 . From these measurements, the user may cut the rails  32  to size. Usually, both of the side rails  32 . 1  will be the cut to the same length. Likewise, the top rail  32 . 2  and the bottom rail  32 . 3  will be cut to length. It is, however, understood that occasionally the frame  14  will not be an exact rectangle and it will become necessary to cut one of a pair of the rails  32  to a slightly different length to accommodate the out of square condition of the frame  14 . Alternatively, the corners  34  may adjust slightly, allowing fine tuned adjustment.  
         [0028]    After the rails  32  have been cut to length, the user may inserts the exposed ends of the tenons  36  into the rails  32  thus assembling the perimeter of the insert  12 . The user may then place the assembled insert  12  into the frame  14  to test the fit. When a suitable fit has been obtained, the user may then proceed to install the sheet  50 .  
         [0029]    The user will then select an appropriate sheet  50 . The user may select a screen type of sheet when the user intends airflow to be allowed through the window, or the user may select a polymer film sheet  50  when the user intends to prevent airflow through the window. A mosaic, preformed or user created, translucent films or other films may also be selected as sheet  50 .  
         [0030]    To install the sheet  50 , the user may first select and when necessary prepare a suitable adhesive to secure the sheet  50  to the rails  32 . The adhesive is spread onto the surface of the rails  32  and the selected sheet  50  is placed on and pressed into the adhesive and loosely stretched to remove wrinkles, etc. With the sheet  50  thus located on the rails  32 , the adhesive may be allowed to cure. The time necessary for the adhesive to cure will be dependant on the composition of the adhesive used and may vary from a matter of seconds with a fast drying cyanoacrylic adhesive to a day with some of the slow curing adhesives.  
         [0031]    After the adhesive has sufficiently cured, the sheet  50  may be stretched. The user selects one of a pair of opposing rails  32 , for example, the bottom rail  32 . 3 , and secures the rail  32 . 3 . Various mechanisms may be used to rotationally secure a rail  32  to a tenon  36 . The rail  32  may be secured to the corner  34  using adhesives, welding, fusing, or mechanical fasteners. Thus, when an adhesive is used, the rail  32  can be temporarily secured, perhaps with clamps, from rotation while the adhesive sets sufficiently to prevent further rotation of the rail  32 . Adhesives, welding, or fusion are suitable and useful in a production application, however, it has been found that the preferred fastener for an end user to install is a simple wood or sheet metal screw.  
         [0032]    With one rail  32 . 3  thus secured, the user may then rotate the opposing top rail  32 . 2  to stretch the sheet  50  and smooth the surface of the sheet  50 . With the sheet  50  thus tensioned, the user may then secure the top rail  32 . 2 .  
         [0033]    A user to pre-drill holes for the insertion of the screws  38  through the rails  32  and into tenons  36 . Alternatively, self-drilling screws  38  may obviate the need for the user to drill the rails  32  and tenons  36  to accept the screws  38 . Most preferably, the rails  32  may hold the sheet  50  in a stretched position, held by clamps, while holes are drilled and screws inserted through the rails  32  and into tenons  36 .  
         [0034]    After tensioning in the first direction, the user would then follow the same steps rotating and securing the side rails  32 . 1  to provide the necessary tension in the second direction.  
         [0035]    After the tensioning is complete, the user then can take the resilient sealer  60  and attach the sealer  60  to the perimeter of the insert  12 . Using the preferred sealer, the user need only cut a strip of the sealer  60  to the approximate length of the perimeter of the insert  12 , remove the tape exposing the pressure sensitive adhesive and press the sealer  60  onto the periphery of the insert  12  to join the sealer  60  to the insert  12 . When all of the sides  32  of the insert  12  are covered, any excess of the sealer  60  may be cut away using a scissors or a knife. The insert  12  is now ready for placement in the frame  14 . Instead of using sealer in the form of a tape, foam pipe insulation may be used. The foam, readily available in stores comes in lengths with a precut slit and interior channel which may be fit around the edges of the insert  12 .  
         [0036]    In some instances, where a user is attempting to minimize heat transfer through a window, it is advantageous to place a second sheet  50  of transparent material on the insert. At this time, however, the rails  32  cannot be rotated to tension the second sheet  50 , so a different material must be used. The preferred material is a heat shrinkable transparent film. Material of the type is well know in the art and readily available from numerous sources, including 3M Company, St. Paul, Minn.  
         [0037]    The heat shrinkable second sheet  50  may be placed over the insert  12  on the side that is not already covered, creating an air pocket, and secured using any suitable mechanism. Typically film of this type is sold with double faced pressure sensitive tape which allows the tape to be placed on and stick to the face or perimeter of the insert  12  and the film then placed on and retained by the second sticky surface of the tape.  
         [0038]    After the second sheet  50  has been so placed and trimmed, if necessary, heat is applied to the second sheet  50  causing the sheet to shrink and tension the sheet  50  on the insert  12 . Preferably, the heat source is a hot air source such as a heat gun or a gun type hair dryer.  
         [0039]    When the user is preparing a large insert  12 , which may include triangulators  33 , the triangulators  33  are installed after the rails  32  have been tensioned and secured and before the optional second sheet  50  is placed on the insert.  
         [0040]    The insert  12  is simply placed into the opening  14  and pressed in against the sashes  24  in the frame  14 . In many instances, friction between the sealer  60  and the frame  14  is sufficient to retain the insert  12  in place. However, it may become necessary to further secure the insert  12  in some instances, owing to either limited friction between the sealer  60  and the frame  14  or for security concerns.  
         [0041]    When the insert  12  must be further secured into the frame  14 , this may be simple and expeditiously accomplished by drilling through two or more rails  32  and driving a screw  38  through the hole thus produced and into the jam  22 . This process will secure the insert  12  so that the insert  12  will not inadvertently come out while allowing the user to intentionally remove the insert  12  and will further tighten the sheet  50 .  
         [0042]    Occasionally it may become necessary for the user to replace the sheet  50  or the sealer  60  due to damage. To replace the sheet  50 , the user would first remover the sealer  60  from the insert  12  and would then reverse the process on installation previously described. After the sheet  50  had been removed, the user would select a replacement sheet  50  and install the sheet  50  in the same manner that the original sheet  50  had been installed.  
         [0043]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize changes may be made in form and detail without departing from the spirit and scope of the invention

Summary:
A window covering, including an insert including a top rail and a bottom rail joined to at least two side rails, the insert including a front face a back face and an outer periphery; a first sheet spanning the front face and joined to each of the rails, opposing rails being rotatable in opposite directions to tension the sheet and the rails being lockable to prevent loosening of the sheet; and a sealer circumscribing an outer periphery of the insert and a method of manufacture including the steps of removing the first sheet from the insert; replacing the first sheet with a new sheet; tensioning the new sheet; and placing the insert into the window frame.