Patent Publication Number: US-8966839-B2

Title: Window assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 61/523,556 filed Aug. 15, 2011, the entire content of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to windows, and more particularly to window coverings. 
     BACKGROUND OF THE INVENTION 
     Numerous products are in the marketplace for covering or insulating windows in residential and commercial buildings to reduce the amount of thermal energy transferred through the windows. Such window coverings may be used during the winter when it is desirable to reduce the amount of heat in the residential or commercial building that is lost to the environment through the windows. Likewise, such window coverings may be used during the summer when it is desirable to reduce the amount of conditioned air in the residential or commercial building that is lost to the environment through the windows. 
     For example, such a window covering may include a thin, plastic sheet adhered to the periphery of the window frame to provide an insulation space between the sheet and the window sash or sashes. However, such window coverings are typically difficult to install and are unsightly. Other such window coverings may include a polymer-based panel and separate frame segments surrounding the periphery of the panel. However, such window coverings are typically fastened to the window frame either directly or using intermediate brackets. When such window coverings are removed from the window frame, however, the installation holes in the window frame from the fasteners, or the intermediate brackets if used, are often unsightly. 
     SUMMARY OF THE INVENTION 
     The invention provides, in one aspect, a window assembly adapted to be positioned within a window frame. The window assembly includes a retainer attachable to the window frame, a transparent panel having an edge, and a frame member attached to the edge and including a lip extending along a substantial length of the frame member. The lip is secured to the retainer by a snap-fit. 
     Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a window assembly according to one embodiment of the invention exploded from a window frame and sash. 
         FIG. 2  is a cross-sectional view of the window assembly of  FIG. 1 , along line  2 - 2 , installed in the window frame. 
         FIG. 3  is an exploded perspective view of the window assembly of  FIG. 1 . 
         FIG. 4  is a reverse, exploded perspective view of the window assembly of  FIG. 3 . 
         FIG. 5  is a cross-sectional view of the window assembly of  FIG. 1  along line  5 - 5 . 
         FIG. 6  is a cross-sectional view of the window assembly of  FIG. 1  along line  6 - 6 . 
         FIG. 7  is an exploded perspective view of a window assembly according to another embodiment of the invention. 
         FIG. 8  is a reverse, exploded perspective view of the window assembly of  FIG. 7 . 
         FIG. 9  is a cross-sectional view of the window assembly of  FIG. 7  installed within a window frame and sash. 
         FIG. 10  is an exploded perspective view of a window assembly according to yet another embodiment of the invention. 
         FIG. 11  is a reverse, exploded perspective view of the window assembly of  FIG. 10 . 
         FIG. 12  is a cross-sectional view of the window assembly of  FIG. 10  installed within a window frame and sash. 
         FIG. 13  is a cross-sectional view of an alternative construction of the frame members of the window assembly of  FIG. 7 . 
         FIG. 14  is an exploded perspective view of a window assembly according to a further embodiment of the invention. 
         FIG. 15  is a cross-sectional view of the window assembly of  FIG. 14  installed within a window frame and sash. 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a window assembly  10  that is removably coupled to a window frame  14  in the interior of a residential, commercial, or other type of building. As is discussed below in more detail, the window assembly  10  is positioned in the window frame  14  and spaced from a sash  18  supported in the window frame  14  to provide an air pocket  22  between the sash  18  and the window assembly  10  ( FIG. 2 ) that increases the effective thermal resistance or insulation value (i.e., “R-value”) of the sash  18 , thereby reducing the amount of thermal energy transferred through the sash  18 , both to and from the interior environment of the building. Alternatively, the window assembly  10  may be positioned in a window frame on the exterior of the building. 
     With reference to  FIGS. 3 and 4 , the window assembly  10  includes a panel  26  having a top edge  30 , a bottom edge  34 , and two side edges  38 ,  42  interconnecting the top and bottom edges  30 ,  34 . The panel  26  is transparent, and may be made from a plastic material or glass. Preferably, the panel  26  is made from a transparent thermoplastic, such as an acrylate polymer (for example, polymethyl methacrylate or polycarbonate). 
     The window assembly  10  also includes elongated top, bottom, and side frame members  46 ,  50 ,  54 ,  58  that are attached, respectively, to the top, bottom, and side edges  30 ,  34 ,  38 ,  42  of the panel  26 . Each of the frame members  46 ,  50 ,  54 ,  58  includes a substantially identical cross-sectional shape in a plane that is oriented normal to the length of the respective frame members  46 ,  50 ,  54 ,  58 . The frame members  46 ,  50 ,  54 ,  58  may also be made from a plastic material and manufactured using an extrusion process. As such, the frame members  46 ,  50 ,  54 ,  58  can be manufactured in generic or standard lengths, and custom trimmed by the end user (e.g., using shears or a saw) in accordance with the particular dimensions of the window frame  14  in which the window assembly  10  will be installed. 
     With continued reference to  FIGS. 3 and 4 , each of the frame members  46 ,  50 ,  54 ,  58  includes an inboard portion  62  to which the panel  26  is attached. In the illustrated construction of the window assembly  10 , the inboard portion  62  of each of the frame members  46 ,  50 ,  54 ,  58  includes a channel  66  and four resiliently deflectable fingers  70  extending into the channel  66 . Particularly, the fingers  70  are grouped in opposed pairs, and the panel  26  is engaged by the fingers  70  when inserted into the channel  66  (see also  FIG. 5 ). The fingers  70  deflect downwardly from the frame of reference of  FIG. 5  in response to insertion of the panel  26  between the fingers  70 . The fingers  70 , therefore, effectively function as barbs to secure the frame members  46 ,  50 ,  54 ,  58  to the respective edges  30 ,  34 ,  38 ,  42  of the panel  26  and inhibit inadvertent removal of the frame members  46 ,  50 ,  54 ,  58  from the panel  26 . In the illustrated construction of the window assembly  10 , the fingers  70  are integrally formed as a single piece with the remainder of the respective frame members  46 ,  50 ,  54 ,  58  using a dual-durometer extrusion process. As such, the fingers  70  may be extruded using a flexible polymeric material (e.g., flexible PVC), while the remainder of the frame members  46 ,  50 ,  54 ,  58  may be extruded using a rigid polymeric material (e.g., rigid PVC). Alternatively, more or fewer fingers  70  may be used in each of the frame members  46 ,  50 ,  54 ,  58 . As a further alternative, the inboard portion  62  of each of the frame members  46 ,  50 ,  54 ,  58  may include different structure for securing the frame members  46 ,  50 ,  54 ,  58  to the respective edges  30 ,  34 ,  38 ,  42  of the panel  26  (e.g., fasteners, adhesives, etc.). 
     With reference to  FIGS. 3 and 4 , each of the frame members  46 ,  50 ,  54 ,  58  also includes an outboard portion  74  including a projection  78  extending along the length of each of the frame members  46 ,  50 ,  54 ,  58 . As shown in  FIG. 5 , the projection  78  is somewhat T-shaped, and a recess  82  is defined on either side of the projection  78 . Alternatively, the projection  78  may be configured having any of a number of different cross-sectional shapes. 
     The window assembly  10  also includes a seal  86  coupled to the outboard portion  74  of each of the frame members  46 ,  50 ,  54 ,  58 . With continued reference to  FIG. 5 , the seal  86  includes a groove  90  having a cross-sectional shape that is complementary to the cross-sectional shape of the projection  78  on each of the frame members  46 ,  50 ,  54 ,  58  such that the projection  78  may be received within the groove  90 . The groove  90  is defined by spaced tangs  94  having a complementary shape to the respective recesses  82  in which the tangs  94  are received. The inter-engagement of the tangs  94  and the projection  78  secures the seal  86  to each of the frame members  46 ,  50 ,  54 ,  58 , and is sufficient to substantially inhibit the seal  86  from being inadvertently removed from the respective frame members  46 ,  50 ,  54 ,  58 . Alternatively, the tangs  94  and the recesses  82  may have any of a number of different complementary cross-sectional shapes to secure the seal  86  to each of the frame members  46 ,  50 ,  54 ,  58 . 
     The seal  86  is made from an elastomeric material (e.g., a natural rubber or a synthetic rubber), and is deformable or flexible in response to the window assembly  10  being installed or inserted into the window frame  14  (see  FIG. 2 ). As such, the seal  86  can adapt the window assembly  10  for use with window frames  14  having adjacent sides that are not square (i.e., angularly spaced by ninety degrees). Such adaptability also permits an increased margin of error when sizing the panel  26  for a particular window frame  14 . For example, the seal  86  may accommodate up to about one-half of an inch of variation of the length and/or width of the panel  26  when sizing multiple panels  26  for the same size window frame  14 . 
     With reference to  FIGS. 3 and 4 , the window assembly  10  includes four corner members  98  interconnecting adjacent frame members  46 ,  50 ,  54 ,  58 . Each of the corner members  98  includes two protrusions or posts  102  that define an included angle of about ninety degrees. As a result, when adjacent frame members  46 ,  50 ,  54 ,  58  are interconnected by a corner member  98 , the included angle between the adjacent frame members  46 ,  50 ,  54 ,  58  is also about ninety degrees. Each of the frame members  46 ,  50 ,  54 ,  58  includes an aperture  106  extending longitudinally and positioned between the inboard portion  62  and the outboard portion  74  of the frame member  46 ,  50 ,  54 ,  58 . In the illustrated construction of the window assembly  10 , the posts  102  and the apertures  106  include complementary square cross-sectional shapes to permit the posts  102  to be received within the apertures  106 . Alternatively, the posts  102  and the apertures  106  may include any number of different complementary cross-sectional shapes to interconnect adjacent frame members  46 ,  50 ,  54 ,  58 . Also, in the illustrated construction of the window assembly  10 , the posts  102  are interference fit to the respective apertures  106  to interconnect and secure the corner members  98  to adjacent frame members  46 ,  50 ,  54 ,  58 . Alternatively, different structure may be utilized to secure the corner members  98  to the frame members  46 ,  50 ,  54 ,  58  after the posts  102  have been inserted into the apertures  106  (e.g., a set screw, adhesives, etc.). 
     The combination of the frame members  46 ,  50 ,  54 ,  58  and the four corner members  98  may be considered a frame assembly which, in alternative constructions of the window assembly  10 , may include fewer than eight total pieces (i.e., four frame members  46 ,  50 ,  54 ,  58  and four corner members  98 ). For example, the frame assembly may be configured as two pieces that interconnect and capture therebetween the panel  26 . As a further alternative, the frame assembly may be integrally formed as a single piece around the panel  26 , which would be cut to a standard window frame size. 
     With continued reference to  FIGS. 3 and 4 , each of the corner members  98  includes an outboard edge  110  defined by a radius to facilitate wrapping the seal  86  around the corner member  98  and transitioning the seal  86  from one frame member  46 ,  50 ,  54 ,  58  to another. Particularly, the corner member  98  reorients the seal  86  to permit the seal  86  to span respective interfaces  114  between the corner member  98  and adjacent frame members  46 ,  50 ,  54 ,  58 . In this manner, the seal  86  may be configured as a single length, having opposed ends which are subsequently bonded (e.g., using an adhesive, etc.) after being wrapped around the outboard portions  74  of the respective frame members  46 ,  50 ,  54 ,  58  and the outboard edges  110  of the corner members  98 . In the illustrated construction of the window assembly  10 , each of the corner members  98  includes two spaced, parallel grooves  118  formed in the outboard edge  110  in which the respective tangs  94  of the seal  86  are positioned (see  FIG. 6 ). Consequently, the seal  86  may sit flush against the outboard edge  110 . The width and depth of each of the grooves  118  are sized to provide a clearance fit with the tangs  94 . 
     With reference to  FIGS. 2 and 4 , each of the frame members  46 ,  50 ,  54 ,  58  includes an extension or lip  122  engaged with the sash  18  to facilitate consistent spacing between the panel  26  and the sash  18  near each edge  30 ,  34 ,  38 ,  42  of the panel  26 . Moreover, each of the lips  122  is sized to optimize the depth of the air pocket  22 . For example, in the illustrated construction of the window assembly  10 , the lips  122  are sized to provide a linear dimension S between the frame members  46 ,  50 ,  54 ,  58  and the sash  18  of about one inch. Alternatively, the lips  122  may be sized to provide any of a number of different depth values depending upon the particular individual insulation valves of the panel  26  and the sash  18 . With continued reference to  FIG. 2 , each of the frame members  46 ,  50 ,  54 ,  58  includes a notch  126  at the base of the lip  122  to facilitate resilient deflection of the lip  122  when the window assembly  10  is installed in the window frame  14 . As such, the lips  122  of the respective frame members  46 ,  50 ,  54 ,  58 , if deflected, may develop a frictional force with the individual sides of the window frame  14  to secure the window assembly  10  within the frame  14 . 
     Each of the corner members  98  includes an extension or lip  130 , which is also configured to space the window assembly  10  from the sash  18  ( FIG. 4 ). Each of the lips  130  includes adjacent edges  134  defining an included angle of about ninety degrees. The lips  130  are not configured to deflect substantially when the window assembly  10  is installed in the window frame  14 . The lips  130  are sized in accordance with the lips  122  on the frame members  46 ,  50 ,  54 ,  58  to provide the same spacing relative to the sash  18  as the frame members  46 ,  50 ,  54 ,  58 . 
     To create the window assembly  10 , one would first cut the panel  26  to appropriate length and width dimensions. Then, the corner members  98  may be positioned on the respective corners of the panel  26 , and the distance between the facing interfaces  114  of opposed corner members  98  may be measured to obtain the length of the frame member  46 ,  50 ,  54 ,  58  extending between those two corner members  98 . If provided in standard lengths, the top, bottom, and side frame members  46 ,  50 ,  54 ,  58  are then individually cut according to the measured lengths of the respective frame members  46 ,  50 ,  54 ,  58 . After the frame members  46 ,  50 ,  54 ,  58  are cut to length and the corner members  98  have been removed from the panel  26 , the side edges  38 ,  42  of the panel  26  are inserted into the channels  66  of the side frame members  54 ,  58 , causing the fingers  70  to resiliently deflect thereby securing the side frame members  54 ,  58  to the panel  26 . 
     Two corner members  98  may then be attached to the respective ends of each of the top frame member  46  and the bottom frame member  50 . The pre-assembled corner members  98  and frame members  46 ,  50  may then be attached to the top and bottom edges  30 ,  34  of the panel  26 , simultaneously inserting the vertically oriented posts  102  of the corner members  98  (i.e., from the frame of reference of  FIG. 3 ) into the apertures  106  of the side frame members  54 ,  58 . Lastly, the seal  86  may be wrapped around the assembled frame members  46 ,  50 ,  54 ,  58  and corner members  98 , during which the projection  78  of each of the frame members  46 ,  50 ,  54 ,  58  is inserted into the groove  90  in the seal  86 . If the seal  86  is provided as a single length having opposed ends, the ends may then be bonded (e.g., using an adhesive, etc.) such that the seal  86  is contiguous and spans all of the interfaces  114  between the corner members  98  and the frame members  46 ,  50 ,  54 ,  58 . 
     The completed window assembly  10  is then installed (i.e., pushed) into the window frame  14  until the lips  122 ,  130  of the respective frame members  46 ,  50 ,  54 ,  58  and the corner members  98  contact the sash  18 . Upon contact with the sash  18 , the window assembly  10  is spaced from the sash  18  an optimal distance to increase the effective R-value of the sash  18 . 
       FIGS. 7-9  illustrate a window assembly  210  according to another embodiment of the invention that may be removably coupled to the window frame  14  shown in  FIG. 1 . With reference to  FIGS. 7 and 8 , the window assembly  210  includes a panel  226  having a top edge  230 , a bottom edge  234 , and two side edges  238 ,  242  interconnecting the top and bottom edges  230 ,  234 . The panel  226  is transparent, and may be made from a plastic material or glass. Preferably, the panel  226  is made from a transparent thermoplastic, such as an acrylate polymer (for example, polymethyl methacrylate or polycarbonate). 
     The window assembly  210  also includes elongated top, bottom, and side frame members  246 ,  250 ,  254 ,  258  that are attached, respectively, to the top, bottom, and side edges  230 ,  234 ,  238 ,  242  of the panel  226 . Each of the frame members  246 ,  250 ,  254 ,  258  includes a substantially identical cross-sectional shape in a plane that is oriented normal to the length of the respective frame members  246 ,  250 ,  254 ,  258 . The frame members  246 ,  250 ,  254 ,  258  may also be made from a plastic material and manufactured using an extrusion process. As such, the frame members  246 ,  250 ,  254 ,  258  can be manufactured in generic or standard lengths, and custom trimmed by the end user (e.g., using shears or a saw) in accordance with the particular dimensions of the window frame  14  in which the window assembly  210  will be installed. 
     With continued reference to  FIGS. 7 and 8 , each of the frame members  246 ,  250 ,  254 ,  258  includes an inboard portion  262  to which the panel  226  is attached. In the illustrated construction of the window assembly  210 , the inboard portion  262  of each of the frame members  246 ,  250 ,  254 ,  258  includes a channel  266  and four resiliently deflectable fingers  270  extending into the channel  266 . Particularly, the fingers  270  are grouped in opposed pairs, and the panel  226  is engaged by the fingers  270  when inserted into the channel  266  (see also  FIG. 9 ). The fingers  270  deflect upwardly from the frame of reference of  FIG. 9  in response to insertion of the panel  226  between the fingers  270 . The fingers  270 , therefore, effectively function as barbs to secure the frame members  246 ,  250 ,  254 ,  258  to the respective edges  230 ,  234 ,  238 ,  242  of the panel  226  and inhibit inadvertent removal of the frame members  246 ,  250 ,  254 ,  258  from the panel  226 . In the illustrated construction of the window assembly  210 , the fingers  270  are integrally formed as a single piece with the remainder of the respective frame members  246 ,  250 ,  254 ,  258  using a dual-durometer extrusion process. As such, the fingers  270  may be extruded using a flexible polymeric material (e.g., flexible PVC), while the remainder of the frame members  246 ,  250 ,  254 ,  258  may be extruded using a rigid polymeric material (e.g., rigid PVC). Alternatively, more or fewer fingers  270  may be used in each of the frame members  246 ,  250 ,  254 ,  258 . As a further alternative, the inboard portion  262  of each of the frame members  246 ,  250 ,  254 ,  258  may include different structure for securing the frame members  246 ,  250 ,  254 ,  258  to the respective edges  230 ,  234 ,  238 ,  242  of the panel  226  (e.g., fasteners, adhesives, etc.). 
     With reference to  FIGS. 7 and 8 , each of the frame members  246 ,  250 ,  254 ,  258  also includes an outboard portion  274  including a seal  286 . The seal  286  is made from a polymeric material (e.g., flexible PVC), and is deformable or flexible in response to the window assembly  210  being installed or inserted into the window frame  14  ( FIG. 9 ). As such, the seal  286  can adapt the window assembly  210  for use with window frames  14  having adjacent sides that are not square (i.e., angularly spaced by ninety degrees). Such adaptability also permits an increased margin of error when sizing the panel  226  for a particular window frame  14 . For example, the seal  286  may accommodate up to about one-half of an inch of variation of the length and/or width of the panel  226  when sizing multiple panels  226  for the same size window frame  14 . In the illustrated construction of the window assembly  210 , the seal  286  is integrally formed as a single piece with the remainder of the respective frame members  246 ,  250 ,  254 ,  258  using a dual-durometer extrusion process. As such, the seals  286  may be extruded using a flexible polymeric material (e.g., flexible PVC), while the remainder of the frame members  246 ,  250 ,  254 ,  258  may be extruded using a rigid polymeric material (e.g., rigid PVC). 
       FIG. 13  illustrates an alternative construction of the frame members. Like features are identified with like reference numerals with the letter “a” and will not be described again in detail. Each of the frame members  246   a ,  250   a ,  254   a ,  258   a  includes a seal  296  having a cylindrical shape that is spaced from the bodies of the respective frame members  246   a ,  250   a ,  254   a ,  258   a  by a stem  297 . The seal  296  is deformable or flexible in a similar manner as the seal  286  described above and shown in  FIGS. 7-9 . 
     With reference to  FIGS. 7 and 8 , the window assembly  210  includes four corner members  298  interconnecting adjacent frame members  246 ,  250 ,  254 ,  258 . Each of the corner members  298  includes two protrusions or posts  302  that define an included angle of about ninety degrees. As a result, when adjacent frame members  246 ,  250 ,  254 ,  258  are interconnected by a corner member  298 , the included angle between the adjacent frame members  246 ,  250 ,  254 ,  258  is also about ninety degrees. Each of the frame members  246 ,  250 ,  254 ,  258  includes an aperture  306  extending longitudinally and positioned between the inboard portion  262  and the outboard portion  274  of the frame member  246 ,  250 ,  254 ,  258 . In the illustrated construction of the window assembly  210 , the posts  302  and the apertures  306  include complementary square cross-sectional shapes to permit the posts  302  to be received within the apertures  306 . Alternatively, the posts  302  and the apertures  306  may include any number of different complementary cross-sectional shapes to interconnect adjacent frame members  246 ,  250 ,  254 ,  258 . Also, in the illustrated construction of the window assembly  210 , the posts  302  are interference fit to the respective apertures  306  to interconnect and secure the corner members  298  to adjacent frame members  246 ,  250 ,  254 ,  258 . Alternatively, different structure may be utilized to secure the corner members  298  to the frame members  246 ,  250 ,  254 ,  258  after the posts  302  have been inserted into the apertures  306  (e.g., a set screw, adhesives, etc.). 
     With continued reference to  FIGS. 7 and 8 , each of the corner members  298  includes a wall  310  having a first portion  314  that overlies at least a portion of one of the frame members  246 ,  250 ,  254 ,  258 , and a second portion  318  that overlies at least a portion of an adjacent frame member  246 ,  250 ,  254 ,  258 . Considering the bottom frame member  250 , for example, the walls  310  of the left and right-side corner members  298  overlap the bottom frame member  250  to an extent permitting up to a total of one-half of an inch of adjustment of the combined length of the left and right-side corner members  298  and the bottom frame member  250  without any visible gaps between the corner members  298  and the bottom frame member  250 . Each of the left and right-side corner members  298 , therefore, permit up to one-quarter of an inch of adjustment of the spacing between the respective corner members  298  and the bottom frame member  250 . Likewise, considering the left and right-side frame members  254 ,  258 , for example, the walls  310  of the upper and lower corner members  298  overlap the frame members  254 ,  258  to an extent permitting up to a total of one-half of an inch of adjustment of the combined height of the upper and lower corner members  298  and the left and right-side frame members  254 ,  258  without any visible gaps between the corner members  298  and the frame member  254 ,  258 . Alternatively, the walls may be sized to shield differently sized gaps between the corner members  298  and the frame members  246 ,  250 ,  254 ,  258 . 
     With reference to  FIG. 8 , each of the frame members  246 ,  250 ,  254 ,  258  includes an extension or lip  322  engaged with the sash  18  ( FIG. 9 ) to facilitate consistent spacing between the panel  226  and the sash  18  near each edge  230 ,  234 ,  238 ,  242  of the panel  226 . Moreover, each of the lips  322  is sized to optimize the depth of an air pocket  222  between the sash  18  and the window assembly  210 . For example, in the illustrated construction of the window assembly  210 , the lips  322  are sized to provide a linear dimension S between the frame members  246 ,  250 ,  254 ,  258  and the sash  18  of about one inch. Alternatively, the lips  322  may be sized to provide any of a number of different depth values depending upon the particular individual insulation valves of the panel  226  and the sash  18 . 
     The corner members  298  do not include any extensions or lips engaged with the sash  18 . In addition, the respective walls  310  of the corner members  298  are spaced from the window frame  14  to provide a gap G between the window frame  14  and each of the corner members  298  ( FIG. 9 ). Accordingly, air may flow freely in and out of the air pocket  222 . 
     To create the window assembly  210 , one would first cut the panel  226  to appropriate length and width dimensions. Then, the corner members  298  may be positioned on the respective corners of the panel  226 , and the distance between the opposed corner members  298  may be measured to obtain the length of the frame member  246 ,  250 ,  254 ,  258  extending between those two corner members  298 . As discussed above, the walls permit some leeway in the cut length of the frame members  246 ,  250 ,  254 ,  258  (e.g., up to one-half an inch total for each frame member  246 ,  250 ,  254 ,  258 ). If provided in standard lengths, the top, bottom, and side frame members  246 ,  250 ,  254 ,  258  are then individually cut according to the measured lengths of the respective frame members  246 ,  250 ,  254 ,  258 . After the frame members  246 ,  250 ,  254 ,  258  are cut to length and the corner members  298  have been removed from the panel  226 , the side edges  238 ,  242  of the panel  226  are inserted into the channels  266  of the side frame members  254 ,  258 , causing the fingers  270  to resiliently deflect thereby securing the side frame members  254 ,  258  to the panel  226 . 
     Two corner members  298  may then be attached to the respective ends of each of the top frame member  246  and the bottom frame member  250 . The pre-assembled corner members  298  and frame members  246 ,  250  may then be attached to the top and bottom edges  230 ,  234  of the panel  226 , simultaneously inserting the vertically oriented posts  302  of the corner members  298  (i.e., from the frame of reference of  FIG. 7 ) into the apertures  306  of the side frame members  254 ,  258 . 
       FIGS. 10-12  illustrate a window assembly  410  according to yet another embodiment of the invention that may be removably coupled to the window frame  14  shown in  FIG. 1 . With reference to  FIGS. 10 and 11 , the window assembly  410  includes a panel  426  having a top edge  430 , a bottom edge  434 , and two side edges  438 ,  442  interconnecting the top and bottom edges  430 ,  434 . The panel  426  is transparent, and may be made from a plastic material or glass. Preferably, the panel  426  is made from a transparent thermoplastic, such as an acrylate polymer (for example, polymethyl methacrylate or polycarbonate). 
     The window assembly  410  also includes elongated top, bottom, and side frame members  446 ,  450 ,  454 ,  458  that are attached, respectively, to the top, bottom, and side edges  430 ,  434 ,  438 ,  442  of the panel  426 . Each of the frame members  446 ,  450 ,  454 ,  458  includes a substantially identical cross-sectional shape in a plane that is oriented normal to the length of the respective frame members  446 ,  450 ,  454 ,  458 . The frame members  446 ,  450 ,  454 ,  458  may also be made from a plastic material and manufactured using an extrusion process. As such, the frame members  446 ,  450 ,  454 ,  458  can be manufactured in generic or standard lengths, and custom trimmed by the end user (e.g., using shears or a saw) in accordance with the particular dimensions of the window frame  14  in which the window assembly  410  will be installed. 
     With continued reference to  FIGS. 10 and 11 , each of the frame members  446 ,  450 ,  454 ,  458  includes a base  502  and a cover  506 , the combination of which defines an inboard portion  462  to which the panel  426  is attached. In the illustrated construction of the window assembly  410 , each of the bases includes a groove  510  having a cross-sectional shape that is complementary to the cross-sectional shape of a projection  514  on each of the covers  506  such that the projection  514  may be received within the groove  510  ( FIG. 12 ). The groove  510  is defined by spaced tangs  518  having a complementary shape to respective recesses  520  in the projection  514  in which the tangs  518  are received. The inter-engagement of the tangs  518  and the projection  514  secures the cover  506  to the base  502 , and is sufficient to substantially inhibit the cover  506  from being inadvertently removed from the base  502 . Alternatively, the tangs  518  and the recesses  520  may have any of a number of different complementary cross-sectional shapes to secure the cover  506  to the base  502 . 
     The inboard portion  462  of each of the frame members  446 ,  450 ,  454 ,  458  includes a channel  466  and two resiliently deflectable fingers  470  extending into the channel  466  from the base  502  ( FIG. 12 ). The fingers  470  deflect upwardly from the frame of reference of  FIG. 12  in response to insertion of the panel  426  within the channel  466 . The fingers  470 , therefore, effectively function as barbs to secure the frame members  446 ,  450 ,  454 ,  458  to the respective edges  430 ,  434 ,  438 ,  442  of the panel  426  and inhibit inadvertent removal of the frame members  446 ,  450 ,  454 ,  458  from the panel  426 . In the illustrated construction of the window assembly  410 , the fingers  470  are integrally formed as a single piece with the remainder of the respective frame members  446 ,  450 ,  454 ,  458  using a dual-durometer extrusion process. As such, the fingers  470  may be extruded using a flexible polymeric material (e.g., flexible PVC), while the remainder of the frame members  446 ,  450 ,  454 ,  458  may be extruded using a rigid polymeric material (e.g., rigid PVC). Alternatively, more or fewer fingers  470  may be used in each of the frame members  446 ,  450 ,  454 ,  458 . 
     With reference to  FIGS. 10 and 11 , each of the frame members  446 ,  450 ,  454 ,  458  also includes an outboard portion  474  including an adhesive seal  486  to secure the base  502  of each of the frame members  446 ,  450 ,  454 ,  458  to the window frame  14 . As such, the bases of each of the frame members  446 ,  450 ,  454 ,  458  are semi-permanently connected to the window frame  14 , while the covers  506  of the respective frame members  446 ,  450 ,  454 ,  458  are removable to remove the panel  426  from the window assembly  410 . 
     With reference to  FIGS. 10-11 , each of the frame members  446 ,  450 ,  454 ,  458  includes an extension or lip  522  engaged with the sash  18  ( FIG. 12 ) to facilitate consistent spacing between the panel  426  and the sash  18  near each edge  430 ,  434 ,  438 ,  442  of the panel  426 . Moreover, each of the lips  522  is sized to optimize the depth of an air pocket  422  between the sash  18  and the window assembly  410 . For example, in the illustrated construction of the window assembly  410 , the lips  522  are sized to provide a linear dimension S between the frame members  446 ,  450 ,  454 ,  458  and the sash  18  of about one inch. Alternatively, the lips  522  may be sized to provide any of a number of different depth values depending upon the particular individual insulation valves of the panel  426  and the sash  18 . 
     To create the window assembly  410 , one would first cut the panel  426  to appropriate length and width dimensions. Then, the top, bottom, and side frame members  446 ,  450 ,  454 ,  458  are individually cut to appropriate length dimensions in accordance with the dimensions of the panel  426 . The respective ends of the frame members  446 ,  450 ,  454 ,  458  are miter cut as shown in  FIGS. 10 and 11 , and the edges  430 ,  434 ,  438 ,  442  of the panel  426  are inserted into the channels  466  of the frame members  446 ,  450 ,  454 ,  458 , causing the fingers  470  to resiliently deflect thereby securing the frame members  446 ,  450 ,  454 ,  458  to the panel  426 . The finished window assembly  410  may then be positioned within the window frame  14  to engage the adhesive seal  486  with the window frame  14  to secure the window assembly  410  in the window frame  14 . 
       FIGS. 14 and 15  illustrate a window assembly  610  according to another embodiment of the invention that may be removably coupled to the window frame  14  shown in  FIG. 1 . With reference to  FIG. 14 , the window assembly  610  includes a panel  626  having a top edge  630 , a bottom edge  634 , and two side edges  638 ,  642  interconnecting the top and bottom edges  630 ,  634 . The panel  626  is transparent, and may be made from a plastic material or glass. Preferably, the panel  626  is made from a transparent thermoplastic, such as an acrylate polymer (for example, polymethyl methacrylate or polycarbonate). 
     The window assembly  610  also includes elongated top, bottom, and side frame members  646 ,  650 ,  654 ,  658  that are attached, respectively, to the top, bottom, and side edges  630 ,  634 ,  638 ,  642  of the panel  626 . Each of the frame members  646 ,  650 ,  654 ,  658  includes a substantially identical cross-sectional shape in a plane that is oriented normal to the length of the respective frame members  646 ,  650 ,  654 ,  658 . The frame members  646 ,  650 ,  654 ,  658  may also be made from a plastic material and manufactured using an extrusion process. As such, the frame members  646 ,  650 ,  654 ,  658  can be manufactured in generic or standard lengths, and custom trimmed by the end user (e.g., using shears or a saw) in accordance with the particular dimensions of the window frame  14  in which the window assembly  610  will be installed. 
     With continued reference to  FIG. 14 , each of the frame members  646 ,  650 ,  654 ,  658  includes an inboard portion  662  to which the panel  626  is attached. In the illustrated construction of the window assembly  610 , the inboard portion  662  of each of the frame members  646 ,  650 ,  654 ,  658  includes a channel  666  and four resiliently deflectable fingers  670  extending into the channel  666 . Particularly, the fingers  670  are grouped in opposed pairs, and the panel  626  is engaged by the fingers  670  when inserted into the channel  666  ( FIG. 15 ). The fingers  670  deflect upwardly from the frame of reference of  FIG. 15  in response to insertion of the panel  626  between the fingers  670 . The fingers  670 , therefore, effectively function as barbs to secure the frame members  646 ,  650 ,  654 ,  658  to the respective edges  630 ,  634 ,  638 ,  642  of the panel  626  and inhibit inadvertent removal of the frame members  646 ,  650 ,  654 ,  658  from the panel  626 . In the illustrated construction of the window assembly  610 , the fingers  670  are integrally formed as a single piece with the remainder of the respective frame members  646 ,  650 ,  654 ,  658  using a dual-durometer extrusion process. As such, the fingers  670  may be extruded using a flexible polymeric material (e.g., flexible PVC), while the remainder of the frame members  646 ,  650 ,  654 ,  658  may be extruded using a rigid polymeric material (e.g., rigid PVC). Alternatively, more or fewer fingers  670  may be used in each of the frame members  646 ,  650 ,  654 ,  658 . As a further alternative, the inboard portion  662  of each of the frame members  646 ,  650 ,  654 ,  658  may include different structure for securing the frame members  646 ,  650 ,  654 ,  658  to the respective edges  630 ,  634 ,  638 ,  642  of the panel  626  (e.g., fasteners, adhesives, etc.). 
     With reference to  FIG. 14 , the window assembly  610  includes four corner members  698  interconnecting adjacent frame members  646 ,  650 ,  654 ,  658 . Each of the corner members  698  includes two protrusions or posts  702  that define an included angle of about ninety degrees. As a result, when adjacent frame members  646 ,  650 ,  654 ,  658  are interconnected by a corner member  698 , the included angle between any two of the adjacent frame members  646 ,  650 ,  654 ,  658  is also about ninety degrees. Each of the frame members  646 ,  650 ,  654 ,  658  includes an aperture  706  extending longitudinally and positioned between the inboard portion  662  and the outboard portion  674  of the frame member  646 ,  650 ,  654 ,  658 . In the illustrated construction of the window assembly  610 , the posts  702  and the apertures  706  include complementary square cross-sectional shapes to permit the posts  702  to be received within the apertures  706 . Alternatively, the posts  702  and the apertures  706  may include any number of different complementary cross-sectional shapes to interconnect adjacent frame members  646 ,  650 ,  654 ,  658 . Also, in the illustrated construction of the window assembly  610 , the posts  702  are interference fit to the respective apertures  706  to interconnect and secure the corner members  698  to adjacent frame members  646 ,  650 ,  654 ,  658 . Alternatively, different structure may be utilized to secure the corner members  698  to the frame members  646 ,  650 ,  654 ,  658  after the posts  702  have been inserted into the apertures  706  (e.g., a set screw, adhesives, etc.). 
     With continued reference to  FIG. 14 , each of the corner members  698  includes a wall  710  having a first portion  714  that overlies at least a portion of one of the frame members  646 ,  650 ,  654 ,  658 , and a second portion  718  that overlies at least a portion of an adjacent frame member  646 ,  650 ,  654 ,  658 . Considering the bottom frame member  650 , for example, the walls  710  of the left and right-side corner members  698  overlap the bottom frame member  650  to an extent permitting up to a total of one-half of an inch of adjustment of the combined length of the left and right-side corner members  698  and the bottom frame member  650  without any visible gaps between the corner members  698  and the bottom frame member  650 . Each of the left and right-side corner members  698 , therefore, permit up to one-quarter of an inch of adjustment of the spacing between the respective corner members  698  and the bottom frame member  650 . Likewise, considering the left and right-side frame members  654 ,  658 , for example, the walls  710  of the upper and lower corner members  698  overlap the frame members  654 ,  658  to an extent permitting up to a total of one-half of an inch of adjustment of the combined height of the upper and lower corner members  698  and the left and right-side frame members  654 ,  658  without any visible gaps between the corner members  698  and the frame member  654 ,  658 . Alternatively, the walls may be sized to shield differently sized gaps between the corner members  698  and the frame members  646 ,  650 ,  654 ,  658 . 
     With reference to  FIGS. 14 and 15 , each of the frame members  646 ,  650 ,  654 ,  658  includes an extension or lip  722  extending from the outboard portion  674  along the entire length of each of the frame members  646 ,  650 ,  654 ,  658 . Particularly, each of the frame members  646 ,  650 ,  654 ,  658  includes parallel walls  726  between which the panel  626  is situated, and the lip  722  extends from one of the walls  726  at an included angle with the wall  726  of about 90 degrees ( FIG. 15 ). Each of the lips  722  also includes a ridge  730  extending along the entire length of the lip  722 . The ridge  730  is oriented parallel with the walls  726 , such that a groove  734  having a substantially constant width is defined between one of the walls  726  and the ridge  730 . Another groove  738  is defined on each of the frame members  646 ,  650 ,  654 ,  658  at a location forward of the groove  734  and on an opposite side of the lip  722  as the groove  734 . Further, each of the lips  722  includes a tapered distal end  742 , the purpose of which is described in detail below. 
     With reference to  FIG. 15 , the window assembly  610  is secured to the window frame  14  by a plurality of retainers  746 , only one of which is shown. Particularly, the retainers  746  are configured as four retainer strips  750  corresponding to the respective frame members  646 ,  650 ,  654 ,  658  for interconnecting the frame members  646 ,  650 ,  654 ,  658  to respective sides of the window frame  14 . The retainer strips  750  are secured to the sides of the window frame  14  using adhesive (e.g., double-sided adhesive tape  754 ), though the retainer strips  750  may be secured to the window frame  14  in any of a number of different manners (e.g., using fasteners, etc.). Each of the retainer strips  750  includes a first leg  758  attachable to the window frame  14  (i.e., using the adhesive tape  754 ) and a second leg  762  that is resiliently deflectable relative to the first leg  758 . Particularly, each of the retainer strips  750  includes a living hinge  766  interconnecting the first and second legs  758 ,  762 . Like the frame members  646 ,  650 ,  654 ,  658 , the retainer strips  750  may be extruded in bulk lengths using a rigid polymeric material (e.g., rigid PVC). 
     With continued reference to  FIG. 15 , each of the retainer strips  750  also includes a projection  770  extending from the second leg  762  along the entire length of the retainer strip  750 . The projection  770  includes an apex  774  biased into engagement with the first leg  758  (i.e., when the window assembly  610  is not yet assembled to the retainer strips  750 ) by the living hinge  766 . Another projection  778  extending from the second leg  762  includes a distal end  782  that is also biased into engagement with the first leg  758  by the living hinge  766 . Accordingly, an elongated channel  786  is defined between the respective projections  770 ,  778 . Each of the retainer strips  750  also includes a yet another projection  790  extending from the first leg  758  along the entire length of the retainer strip  750 . The projection  790  is oriented perpendicular to the first leg  758  and includes a shorter length than either of the projections  770 ,  778  on the second leg  762 . 
     With continued reference to  FIG. 15 , the retainer strips  750  are engaged with the sash  18  to facilitate consistent spacing between the panel  626  and the sash  18  near each edge  630 ,  634 ,  638 ,  642  of the panel  626 . Moreover, each of the retainer strips  750  is sized to optimize the depth of an air pocket  722  between the sash  18  and the window assembly  610 . For example, in the illustrated construction of the window assembly  610 , the retainer strips  750  are sized to provide a linear dimension S between the frame members  246 ,  250 ,  254 ,  258  and the sash  18  of at least 0.75 inches. Alternatively, the retainer strips  750  may be sized to provide any of a number of different depth values depending upon the particular individual insulation valves of the panel  626  and the sash  18 . 
     The corner members  698  do not include any extensions or lips engaged with the retainer strips  750  or the sash  18 . In addition, the respective walls  710  of the corner members  698  are spaced from the window frame  14  to provide a gap G between the window frame  14  and each of the corner members  698 . Accordingly, air may flow freely in and out of the air pocket  722  through the gap G. 
     To create the window assembly  610 , one would first cut the panel  626  to appropriate length and width dimensions. Then, the corner members  698  may be positioned on the respective corners of the panel  626 , and the distance between the opposed corner members  698  may be measured to obtain the length of the frame member  646 ,  650 ,  654 ,  658  extending between those two corner members  698 . As discussed above, the walls  710  permit some leeway in the cut length of the frame members  646 ,  650 ,  654 ,  658  (e.g., up to one-half an inch total for each frame member  646 ,  650 ,  654 ,  658 ). If provided in standard lengths, the top, bottom, and side frame members  646 ,  650 ,  654 ,  658  are then individually cut according to the measured lengths of the respective frame members  646 ,  650 ,  654 ,  658 . After the frame members  646 ,  650 ,  654 ,  658  are cut to length and the corner members  698  have been removed from the panel  626 , the side edges  638 ,  642  of the panel  626  are inserted into the channels  666  of the side frame members  654 ,  658 , causing the fingers  670  to resiliently deflect thereby securing the side frame members  654 ,  658  to the panel  626 . 
     Two corner members  698  may then be attached to the respective ends of each of the top frame member  646  and the bottom frame member  650 . The pre-assembled corner members  698  and frame members  646 ,  650  may then be attached to the top and bottom edges  630 ,  634  of the panel  626 , simultaneously inserting the vertically oriented posts  702  of the corner members  698  (i.e., from the frame of reference of  FIG. 14 ) into the apertures  706  of the side frame members  654 ,  658 . 
     The retainer strips  750  may be cut to length in accordance with the interior dimensions of the window frame  14  and attached to the window frame  14  using the adhesive tape  754 . Of course, these steps may be taken prior or subsequent to construction of the window assembly  610 . The window assembly  610  may then be secured to the retainer strips  750  by aligning the lips  722  of the respective frame members  646 ,  650 ,  654 ,  658  with the corresponding retainer strips  750  on the window frame  14 . Particularly, the tapered distal end  742  of each of the lips  722  is initially engaged with the projection  778  on the corresponding retainer strips  750 , and then the window assembly  610  is pushed toward the sill  18 , thereby causing the second leg  762  of each of the retainer strips  750  to deflect away from the first leg  758  as the distal end  782  of the projection  778  slides over the tapered distal end  742  of the lip  722 . 
     The distal end  782  of the projection  778  then encounters the ridge  730  on each of the lips  722  upon further pushing the window assembly  610  toward the sill  18 . The window assembly  610  may be snap-fit to the retainer strips  750  in a first installed depth when the distal end  782  of the projection  778  slides over the ridge  730  (thereby causing the second leg  762  to resiliently deflect farther from the first leg  758 ) and is received in the groove  734 , while simultaneously the projection  790  is received in the groove  738 . In the first installed depth, the ridge  730  is also positioned in the elongated channel  786  defined between the two projections  770 ,  778  on the second leg  750 . However, the window assembly  610  may also be snap-fit to the retainer strips  750  in a second installed depth (shown in  FIG. 15 ), in which the window assembly  610  is pushed further toward the sill  18 , causing the projection  770  to slide over the ridge  730  and snap into the groove  734  with the other projection  778 . Accordingly, the window assembly  610  is secured to the window frame  14  in a rigid and semi-permanent manner. Alternatively, two or more of the frame members  646 ,  650 ,  654 ,  658  may include handles (not shown) to facilitate removal of the window assembly  610  from the retainer strips  750  and the window frame  14  for cleaning the panel  626  and/or the underlying window. 
     Various features of the invention are set forth in the following claims.