Abstract:
A particular method includes installing a window assembly in a structure by coupling a window frame body of the window assembly to a first surface of an interior side of an outer skin of the structure. The method also includes coupling the window frame body to a second surface of an interior side of an inner skin of the structure. The method also includes coupling the window frame body to a portion of the structure between the outer skin and the inner skin.

Description:
CLAIM OF PRIORITY 
     This application is a continuation of and claims priority from U.S. patent application Ser. No. 11/714,456, filed on Mar. 5, 2007, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Window assemblies are installed in a wide variety of structures to permit natural light to enter the structure, to permit occupants of the structure to view outside the structure and, sometimes, to permit viewing of the interior of the structure from the exterior of the structure. Window assemblies can also help isolate and protect the interior of the structure from the environment external to the structure. Such structures can include buildings and vehicles, such as land vehicles, maritime vessels, and aircraft. 
     In some cases, such as when the structure is an aircraft, the window assembly can be part of a pressure boundary to help maintain desired pressure inside the structure. In such a case, an aircraft window assembly may be installed in an aperture that has been excised from aluminum skin of an aircraft fuselage section. 
     However, in a departure from conventional aluminum aircraft skins and structure, honeycomb fuselage skins are being used in aircraft. This use of honeycomb fuselage skins is in keeping with a general desire to reduce aircraft weight. In aircraft with honeycomb fuselage skins, window apertures are excised after final cure of the fuselage honeycomb structure, thereby exposing internal honeycomb structures that entail sealing and closeout to resist moisture ingression. 
     The foregoing examples of related art and limitations associated therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. 
     SUMMARY 
     The following embodiments and aspects thereof are described and illustrated in conjunction with systems and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the problems described above in the Background have been reduced or eliminated, while other embodiments are directed to other improvements. 
     According to an exemplary embodiment, an exemplary window frame assembly includes a window frame and spring clips. The window frame includes a window frame body, and flanges extend from the window frame body. The spring clips are removably attachable to the flanges. 
     According to an aspect, each flange may define at least one first locking member and each spring clip may define at least one second locking member configured to engage the first locking member. As an example, the at least one first locking member may include saw tooth grooves and the at least one second locking member may include a pair of angled tabs. As another example, the at least one first locking member may include a pair of angled tabs and the at least one second locking member may include saw tooth grooves. 
     According to another aspect, each spring clip may further define a release mechanism that is configured to disengage the spring clip and the flange. For example, the release mechanism may include a tab. 
     In addition to the exemplary embodiments and aspects described above, further embodiments and aspects will become apparent by reference to the drawings and by study of the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
         FIG. 1  is an exploded perspective view of an exemplary window frame assembly; 
         FIGS. 2A ,  2 B and  2 C illustrate details of an exemplary embodiment of the window frame assembly of  FIG. 1 ; 
         FIG. 3  is a plan view of the window frame assembly of  FIG. 1 ; 
         FIGS. 4A ,  4 B, and  4 C illustrate further details of an exemplary embodiment of the window frame assembly of  FIG. 1 ; 
         FIGS. 5A ,  5 B, and  5 C illustrate details of another exemplary embodiment of the window frame assembly of  FIG. 1 ; and 
         FIGS. 6A ,  6 B, and  6 C illustrate further details of the other exemplary embodiment of the window frame assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Given by way of non-limiting overview and referring to  FIG. 1 , an exemplary window frame assembly  10  includes a window frame  12  and spring clips  14 . The window frame  12  includes a window frame body  16 , and flanges  18  extend from the window frame body  16 . The spring clips  14  are removably attachable to the flanges  18 . A window assembly  20  may be removably retained in the window frame  12  by the spring clips  14 . Details will be set forth below. 
     Still referring to  FIG. 1 , the window frame assembly  10  can be mounted within a structure  22 . Given by way of non-limiting examples, the structure  22  can be without limitation a maritime vessel with porthole, land vehicle, interior or exterior building wall or roof whose aperture encases a window or skylight portal, or a fuselage of an aircraft. In an exemplary, non-limiting embodiment, the structure  22  suitably is an aircraft&#39;s honeycomb fuselage structure. In such an example, the structure  22  includes an inner skin  24 , such as a composite laminate inner skin, an outer skin  26 , such as a composite laminate outer skin, and internal honeycomb material  28  between the inner skin  24  and the outer skin  26 . 
     The inner skin  24 , the honeycomb material  28 , and the outer skin  26  are excised, thereby defining an aperture  30  to provide visual access through the wall of the structure  22 . The aperture  30  is smaller at the outer skin  26 —that is, less of the outer skin  26  is excised than is the honeycomb material  28  and the inner skin  24 . This arrangement provides a surface  32  against which the window frame  12  can bear and bond. 
     In an exemplary embodiment, the window frame  12  suitably is a metallic or composite window frame that is sized to intimately correspond to the cutout in the honeycomb material  28  and to nest against both the inner skin  24  and the outer skin  26  (at the surface  32 ). All interface surfaces between the window frame  12  and the structure  22  are adhesively bonded to obtain homogenous load carrying capability through the window frame assembly  10  as well as provide a sealed barrier over the honeycomb material  28  to prevent moisture ingression. 
     The window frame body  16  includes external surfaces that interface with the structure  22 . A frame surface  34  is coincident to the surface of the cutout of the honeycomb material  28  and is bonded to the honeycomb material  28  with a suitable adhesive, like a two-part adhesive such as without limitation EA9394 paste adhesive. Approximately perpendicular to the surface  34  are surfaces  36  and  38 . The surface  36  interfaces with the outer skin  26  at the surface  32  and the surface  38  interfaces with the inner skin  24 . The same adhesive as described above suitably is applied to the surfaces  36  and  32  and to the surfaces  38  and  24  to bond them and to provide a seal against moisture. An interior of the surface  36  also serves as a sill  40  in which the window assembly  20  will bear against. 
     Referring additionally to  FIGS. 2A ,  2 B, and  2 C, the flanges  18  are substantially rectangular, upstanding projections that project from the internal side of the window frame body  16  approximately perpendicular to the inner skin  24  and the outer skin  26 . The flanges  18  provide a means for aligning and holding the spring clips  14  that are used to retain the window assembly  20  in place against the sill  40 . Any number of the flanges  18  may be provided as desired to retain the window assembly  20  in any particular application. The number of the flanges  18  that are used may depend, in part on factors such as size of the window assembly  20 , size of the spring clips  14 , associated loads, and the like. When the number of spring clips  14  is reduced and the spring clip  14  is installed to a height which does not fully compress the biasing portion  50 , the inherent flexure in this spring attach mechanism additionally provides a means of absorbing blunt exterior impact against the window assembly  20 , thereby minimizing damage to the window glazing material. 
     Integral with the window frame  12  are attachment features that help retain the installed window assembly  20  without the use of fasteners. To that end, each flange  18  provides a locking member  42  that is a means for releasably locking or engaging with the spring clip  14 . In one exemplary, non-limiting embodiment, the locking member  42  may be provided as saw tooth grooves that are defined on a face  44  of the flange  18 . Another exemplary embodiment will be discussed later. 
     The spring clips  14  are snapped into place over the attachment features (that is, the locking member  42 ) of the flanges  18  in such a manner as to hold the window assembly  20  firmly against the sill  40 . The spring clip  14  includes an attachment portion  46  that receives therein the flange  18 . An edge  48  may be curved, if desired, to aid in installation of the spring clip  14  over the flange  18 . A biasing portion  50  is suitably shaped, such as by being bent downwardly towards the window assembly  20 , to apply a preloaded pressure against the window assembly  20  when the spring clip  14  is fully installed and compressed. 
     Integral with the spring clip  14  are attachment features that, along with the attachment features of the flange  18 , help retain the installed window assembly  20  without the use of fasteners. To that end, each spring clip  14  provides a locking member  52  that is a means for releasably locking or engaging with the flange  18 . In one exemplary, non-limiting embodiment, the locking member  52  may be provided as a pair of angled tabs that extend from a face  54  of the attachment portion  46  of the spring clip  14 . In this exemplary, non-limiting embodiment, the pair of dual angled tabs  52  retain the spring clip  14  in position against mating saw tooth grooves  42  of the flange  18 . Another exemplary embodiment will be discussed later. 
     Referring additionally to  FIG. 3 , once the window assembly  20  is placed in position on the sill  40  of the window frame  12 , the spring clips  14  are installed over the flanges  18  and are depressed against the window assembly  20  to retain the window assembly  20  in position. The spring clip  14  is captured in position by the use of the locking members  42  and  52 . In this exemplary, non-limiting embodiment, the pair of angled two locking tabs  52  interface or engage with the saw tooth grooves  42  on the face  44  of the flange  18 . When the spring clip  14  is pressed down over the flange  18 , the tabs  52  are angled such that they will snap over the saw tooth grooves  42  during installation until the spring clip  14  is fully compressed against the window assembly  20 . After installation, the pair of angled tabs  52  are captured in the saw tooth grooves  42  and are unable to move back up the flange  18  (which would unload the compression on the spring clip  14 ). The biasing portion  50  applies a preloaded pressure against the window assembly  20  when the spring clip  14  is fully installed and compressed. To that end, when the structure  22  is an aircraft fuselage, use of some embodiments of window frame assemblies disclosed herein may help reduce weight by up to around a pound or so per installed window assembly over window assemblies installed in aircraft using conventional window frame assemblies. In aircraft having hundreds of window assemblies installed therein, use of some embodiments of window frame assemblies disclosed herein may help contribute to a total weight savings of up to hundreds of pounds or so, depending on the number of installed window assemblies. 
     Referring additionally to  FIGS. 4A ,  4 B, and  4 C, the spring clip  14  includes a release member  56  to help in removal of the window assembly  20 . For example, the release member  56  may be provided in the form of a tab that is fashioned in the face  54  of the spring clip  14 . The release member  56 , such as the tab, suitably is centered between the pair of locking members  52 , such as the pair of angled tabs. The release member  56  provides a face such that a tool  58 , such as a screwdriver, can be inserted to apply a force to rotate the face  54  of the spring clip  14 . The face  54  of the spring clip  14  is rotatably pried open by the tool  58  as shown by arrows  60  to disengage the locking members  52 , such as the pair of angled tabs of the spring clip  14 , from the locking members  42 , such as the saw tooth grooves of the flange  18 . Upon disengaging the locking members  52 , the spring clip  14  will unload the compression load stored against the window assembly  20  and allow for removal from the flange  18 . Once all of the spring clips  14  are removed, the window assembly  20  is free to be removed. 
     Referring now to  FIGS. 5A ,  5 B, and  5 C, in another exemplary embodiment of a window frame assembly  10 A, locking members  42 A and  52 A are similar to the locking members  42  and  52  ( FIGS. 2A ,  2 B, and  2 C), except the implementation of the type of locking members is reversed from the implementation illustrated in  FIGS. 2A ,  2 B, and  2 C. For example, a flange  18 A provides as locking members  42 A angled tabs that extend inwardly from the face  44 . In this embodiment, a spring clip  14 A provides saw tooth grooves  52 A that extend outwardly from the face  54  (that is, away from the flange  18 A). All other details of construction and operation of the window frame assembly  10 A are the same as those set forth above for the window frame assembly  10  and need not be repeated for an understanding of the embodiment. Like reference numbers are used to refer to the same details. 
     Referring now to  FIGS. 6A ,  6 B, and  6 C, the window assembly  20  is removed from the window frame assembly  10 A in a similar manner as discussed above for the window frame assembly  10  ( FIGS. 4A ,  4 B, and  4 C). However, rotation of the face  54  of the spring clip  14 A disengages the saw tooth grooves  52 A of the spring clip  14 A from the tabs  42 A of the flange  18 A. All other details of removal of the window assembly  20  from the window frame assembly  10 A are the same as those discussed above for the window frame assembly  10  ( FIGS. 4A ,  4 B, and  4 C) and need not be repeated. Like reference numbers are used to refer to the same details. 
     While a number of exemplary embodiments and aspects have been illustrated and discussed above, those of skill in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, and sub-combinations as are within their true scope.