Abstract:
A window assembly and method for its installation is provided. The window assembly may include multiple transparent panels covering an opening of an aircraft fuselage. A clip member may be utilized to secure one or more of the transparent panels in place. The clip member may be slideably disposed against a retainer member, and may be adapted to lock in place relative to the retainer member in engaged and disengaged positions.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     Most current passenger aircraft window systems comprise multiple panes of acrylic that are coupled together in a multi-piece sheet metal attachment structure. Typically, this structure is installed from the interior of the aircraft and is not maintenance friendly since the passenger seats and aircraft interior wall fascia panels must be removed for access to the window system. Often, the window systems require a deep envelope in the fuselage to accommodate the bulky sheet metal structure holding the multi-pane window.  
         [0002]     Many next generation aircraft incorporate transparent structural panels fastened around apertures in the fuselage skin to allow occupants of the aircraft to look through the transparent panels. The panels are typically attached directly to the inside of the fuselage skin. These panels often require external fairing panes to fill in the gap between the inside surface of the skin and the outside surface of the skin in order to provide an aerodynamically smooth surface on the outside surface of the fuselage. The external fairing panes may provide for noise abatement, a thermal barrier, and an abrasion resistant barrier for the internally mounted transparent panel.  
         [0003]     The fairing pane attachment system for these next generation aircraft typically must fit inside an envelope equal to the thickness of the fuselage skin, and be capable of allowing installation of the fairing pane from the outside surface of the aircraft fuselage for quick replacement and easy maintenance. Conventional solutions for attaching the outer protective fairing pane have typically been to utilize a picture frame to encase the fairing pane, and fasteners for attachment to the aircraft structure. However, utilizing a picture frame, which generally comprises a raised step around the fairing pane aperture, may not supply a smooth aerodynamic surface on the exterior surface of the fuselage, and may induce drag and reduce performance. Moreover, attachment of fasteners is usually required. Installation of fasteners may be time consuming, may require torque specifications for proper attachment, and may require a maintenance person to remove gloves in order to perform necessary maintenance. Additionally, fasteners may be dropped during maintenance and may cause foreign object damage (FOD) to aircraft systems.  
         [0004]     A window assembly and method for its installation is required which will allow for efficient installation of fairing panes from the outside of the aircraft fuselage in a space-challenged envelope. This window assembly may also be utilized in non-aircraft applications.  
       SUMMARY OF THE INVENTION  
       [0005]     In one aspect of the present invention, a window assembly for an aircraft fuselage may include a first transparent panel, a second transparent panel, and at least one clip member. The first transparent panel may cover at least a portion of an opening in the aircraft fuselage. The clip member may be adapted to be at least partially disposed over at least a portion of the second transparent panel in an engaged position and adapted to not be disposed over the portion of the second transparent panel in a disengaged position.  
         [0006]     In another aspect of the present invention, a window assembly for an aircraft fuselage may include a first transparent panel, a second transparent panel, a first retainer member, and a clip member. The first transparent panel may cover at least a portion of an opening in the aircraft fuselage. The first retainer member may include at least one of a first female portion and a first male portion, while the clip member may include at least one of a second female portion and a second male portion. At least one of the first female and first male portion of the retainer member may be adapted to interlock with at least one of the second female and second male portion of the clip member.  
         [0007]     In a further aspect of the present invention, a method is provided for forming a window assembly on an aircraft fuselage having an opening. A clip member and first and second transparent panels are provided. The first transparent panel may be placed over at least a portion of the opening. The second transparent panel may be placed over at least a portion of the first transparent panel while the clip member can be in a disengaged position. The clip member may be placed in an engaged position to secure the second transparent panel in place.  
         [0008]     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a perspective view of an aircraft incorporating a window assembly in accordance with the present invention;  
         [0010]      FIG. 2  is an enlarged plan view of one of the windows of the aircraft of  FIG. 1 ;  
         [0011]      FIG. 3  is a partial plan view of the retainer assembly of  FIG. 2  without the transparent panels;  
         [0012]      FIG. 4  is an enlarged perspective view of the dotted line area of  FIG. 3  showing clip members in engaged (extended) positions;  
         [0013]      FIG. 5  is an enlarged perspective view of a retainer member of  FIG. 4  showing a clip member being inserted;  
         [0014]      FIG. 6  is a top view of the retainer member of  FIG. 5  showing one clip member in an engaged (extended) position and one clip member in a disengaged (retracted) position;  
         [0015]      FIG. 7  is a top view of the outer transparent panel of  FIG. 2 ;  
         [0016]      FIG. 8  is an enlarged perspective view of the dotted line area of  FIG. 2  showing the clip members in engaged (extended) positions; and  
         [0017]      FIG. 9  is a partial cross-sectional view along lines  9 - 9  of  FIG. 8 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.  
         [0019]     Referring to  FIG. 1 , a plurality of window assemblies  10 , in accordance with a preferred embodiment of the present invention, are illustrated as incorporated into a fuselage  12  of an airplane  14 . The structural and operational properties of the window assembly  10  are especially well suited for use with aircraft, where the window assembly  10  is exposed to significant changes in thermal conditions and air pressure, as well as impacts from foreign objects. In other embodiments, the window assembly  10  may be implemented in non-aircraft applications, such as buses, trains, and ships.  
         [0020]      FIG. 2  depicts an enlarged view of one of the window assemblies  10 . The window assembly  10  may be held to the fuselage  12  by a plurality of fastening elements  16  spaced circumferentially around an opening  18  in which the window assembly  10  can be installed. The fastening elements  16  can extend through pre-formed openings in the fuselage  12 . A retainer assembly  22  may retain the outer transparent panel  24  in place.  
         [0021]      FIG. 3  shows a partial plan view of the retainer assembly  22  of  FIG. 2  attached to a composite filler plate  26 .  FIG. 4  depicts an enlarged perspective view of the dotted line area of  FIG. 3  showing a portion of the retainer assembly  22  in more detail. As shown in  FIGS. 3 and 4 , the composite filler plate  26  may include fourteen tab members  28  extending around an inner surface  30  of the filler plate  26 , and is defined by an opening  34  and by fourteen apertures  36  disposed between the tab members  30 . The carbon filler plate  26  may be made of a carbon fiber and resin or other materials known in the art. The retainer assembly  22  may include fourteen retainer members  40 , each fastened  41  to a respective tab member  30  around the periphery of the opening  34 . The retainer members  40  are preferably Aluminum or another metallic but may be made of any material known in the art. At each of the two opposing ends  42  and  44  of each retainer member  40 , a clip member  46  may be connected to the retainer member  40 , for a total of twenty-eight clip members  46  disposed around the retainer assembly  22 . As shown, while in an engaged (extended) position, a portion  48  of each clip member  46  extends past an end  42  or  44  of its respective retainer member  40  and at least partially over an aperture  36 . The clip members  46  are preferably Titanium or Stainless Steel, but may be made of any material known in the art.  
         [0022]      FIG. 5  shows an enlarged perspective view of a retainer member  40  of  FIG. 4  with a clip member  46  about to be inserted into a t-shaped internal trough  50  of the retainer member  40 . Four sets of retainer holes  52 ,  53 ,  54 , and  55  are drilled through a top surface  56  of the retainer member  40 , at least partially into side surfaces  58  and  59  of the retainer member  40 . In other embodiments, the retainer holes  52 ,  53 ,  54 , and  55  may be in a variety of numbers and configurations and may comprise surface indentations which may or may not comprise through-holes. The clip member  46  can be defined by two slots  60  and two spring tabs  62  disposed outwardly. When the spring tabs  62  are fully extended outwardly, the width w 1  of the end  64  of the clip member  46  may become wider than the width w 2  of the end  66  of the trough  50 . In other embodiments, the retainer member  40 , and clip member  46  may be in a variety of shapes and configurations, and the trough  50  may be internal or external in any number of shapes, sizes, and configurations.  
         [0023]      FIG. 6  is a top view of the retainer member  40  of  FIG. 5  showing one clip member  46 A partially disposed within the trough  50  of the retainer member  40  in an engaged (extended) position, and showing one clip member  46 B completely disposed within the trough  50  of the retainer member  40  in a disengaged (retracted) position. The clip members  46 A and  46 B may be adapted to be slideably disposed within the trough  50 . As shown, when the clip member  46 A is in an engaged position, the spring tabs  62 A may snap into the set of retainer holes  52  to interlock and secure the clip member  46 A with a portion  48  of the clip member  46 A extending past an end  44  of the retainer member  40 . If the clip member  46 B is in a disengaged position, the spring tabs  62 B may snap into the set of retainer holes  54  to interlock and secure the clip member  46 B completely within the trough  50 . In other embodiments, the clip members  46  may be engaged or disengaged from the retainer member  40  using a variety of configurations and types of interlocking male and female portions (such as any type of male member and female hole on both the clip members  46  and retainer member  40 ), mechanisms, or methods.  
         [0024]      FIG. 7  depicts a top view of the outer transparent panel (or fairing pane)  24  of  FIG. 2 . Fourteen molded tabs  68  may be disposed around a periphery of the outer surface  70  of the outer transparent panel  24 . In other embodiments, the outer transparent panel  24  may be in varying configurations. The outer transparent panel  24  is preferably acrylic but may be made of any transparent material known in the art such as glass and a composite.  
         [0025]      FIG. 8  is an enlarged perspective view of the dotted line area of  FIG. 2  showing the clip members  46  in engaged (extended) positions, while  FIG. 9  is a partial cross-sectional view along line  9 - 9  of  FIG. 8 . Collectively,  FIGS. 8 and 9  illustrate the assembly of the internal transparent panel  72 , the Silicone seal  74 , the composite filler plate  26 , the outer transparent panel  24  and its associated tabs  68 , the Polysulphide adhesive  76 , the slip plate  78 , the clip members  46 , the retainer members  40 , the fuselage  12 , and the outer seal  80 . The outer seal  80  may provide access to the window assembly  10  when removed from the fuselage  12 . The internal transparent panel  72  is preferably disposed on the interior of the airplane and may be made of a composite, but in other embodiments, may comprise any transparent material known in the art such as glass or acrylic. A vented cavity  82  may be disposed between a portion  84  of the outer transparent panel  24  and a portion  86  of the internal transparent panel  72 . The vented cavity  82  may be vented to the outside atmosphere thus reducing loads on the outer transparent panel  24 . A silicone seal  74  may be disposed between a portion  88  of the outer transparent panel  24  and a portion  90  of the internal transparent panel  72 . The seal  74  aids in sealing the window assembly  10 , and in other embodiments, may be made of varying materials known in the art. The composite filler plate  26  may be disposed between the internal transparent panel  72  and the outer skin of the aircraft fuselage  12 .  
         [0026]     As shown, when assembled, each of the fourteen tabs  68  of the outer transparent panel  24  are disposed in between two retainer members  40  and over corresponding apertures  36  in the filler plate  26 . Polysulphide adhesive  76  is disposed between each of the fourteen tabs  68  of the outer transparent panel  24  and each of the fourteen corresponding slip plates  78 . The slip plates  78  are preferably Stainless Steel or Aluminum, but in other embodiments may comprise other materials known in the art. Two secured clip members  46 , extending from troughs  50  of opposing retainer members  40 , may be disposed partially over opposing ends  92  and  94  of each slip plate  78 . As such, the outer transparent panel  24  may be fixedly secured in position due to each of the fourteen tabs  68  of the outer transparent panel  24  being held in place by the fourteen respective slip plates  78  and fourteen respective pairs of clip members  46 . The use of fourteen pairs of clip members  46  may provide redundant retention in the possibility that a clip member  26  is installed improperly or fails. Moreover, the use of slip plates  78  may prevent the tabs  68  of the outer transparent panel  24  from disengaging from the clip members  46  when internal pressure is experienced, and also may distribute the bearing loads uniformly across the tabs  68  to largely eliminate fracture of the tabs  68  underneath the clip members  46 .  
         [0027]     During installation of the window assembly  10 , the internal transparent panel  72  may be placed over the opening in the aircraft fuselage  12 . Each of the respective clip members  46  may be retracted within the troughs  50  of the respective retainer members  40  into their disengaged positions allowing the outer transparent panel  24  to be positioned over the internal transparent panel  72 . The clip members  46  may be retracted within the troughs  50  by inserting a flat surface, such as a flat blade or tip of a screwdriver, into the troughs  50  against an end of the clip members  46  and using the flat surface to force the clip members  46  to slide within the troughs  50 . When the clip members  46  are fully retracted within the troughs  50  in their disengaged positions, the clip members  46  may be secured in place as a result of the spring tabs  62  of the clip members  46  being snapped into the retainer holes  53  and  54  within the troughs  50 . The outer transparent panel  24  may be placed over the internal transparent panel  72  with each of the fourteen tabs  68  of the outer transparent panel  24  disposed in between two retainer members  40  and over corresponding apertures  36  in the filler plate  26 . Polysulphide adhesive  76  may be applied to each of the fourteen tabs  68  of the outer transparent panel  24 .  
         [0028]     The fourteen respective slip plates  78  may be positioned over each of the respective adhesive strips  76  and tabs  68 . Each of the twenty-eight clip members  46  may then be extended into their engaged positions, again utilizing a flat surface to force the clip members  46  to slide within the troughs  50 , so that a portion  48  of each clip member  46  extends past an end  42  or  44  of its respective retainer member  40  and at least partially over respective aperture  36  to secure the slip plates  78  and tabs  68  in place. In their engaged positions, the clip members  46  may be secured in place as a result of the spring tabs  62  of the clip members  46  being snapped into the retainer holes  52  and  55  within the troughs  50 . As a result, the outer transparent panel  24  may be fixedly secured within the window assembly  10 . The outer seal  80  may then be secured to seal the window assembly  10 . To later unsecure the outer transparent panel  24 , the outer seal  80  may be removed, and each of the clip members  46  are retracted within the troughs  50  using a flat surface to allow the outer transparent panel  24  to be removed from the window assembly  10 .  
         [0029]     In other embodiments, a varying number of clip members  46 , retainer members  40 , troughs  50 , and slip plates  78  may be utilized in a variety of configurations to secure and un-secure various parts of the window assembly  10 . In still other embodiments, differing configurations, types of parts, locations, and assembly mechanisms may be used for the present invention.  
         [0030]     The invention may allow for an outer transparent panel  24  to be installed or replaced without the use of fasteners, and without the use of costly tools. As a result, the invention may allow for more time effective, efficient, and less costly installation and maintenance of window assemblies  10 .  
         [0031]     It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.