Abstract:
A method and apparatus of bonded wing construction in which skins ( 35, 39 ) having shaped protrusions ( 37, 41 ) are bonded to rib members having correspondingly shaped intrusions ( 33 ). The skins may also include differently shaped protrusions ( 53, 55 ) which are bonded to K-shaped spars ( 51 ) having correspondingly shaped intrusions ( 61, 63 ).

Description:
This application claims the benefit of provisional application No. 60/194,610 filed Apr. 5, 2000. 
    
    
     TECHNICAL FIELD 
     The present invention relates to aircraft wing construction. In particular, the present invention relates to a method and apparatus for a bonded wing construction. 
     DESCRIPTION OF THE PRIOR ART 
     Traditionally, aircraft wing structures were constructed by fastening C-shaped channel spars to the ends of ribs and by mechanically fastening I-beam-stiffened skins to angle clips disposed in channels in the wing ribs. These systems rely purely on mechanical assembly for spar to skin and skin to rib interfaces. 
     SUMMARY OF THE INVENTION 
     There is a need for a bonded wing construction which does not rely purely upon mechanical assembly to establish the necessary spar to skin and rib to skin interfaces without compromising the stiffness of the wing. 
     Therefore, it is an object of the present invention to provide a method and apparatus for bonded wing construction that does not rely purely upon mechanical assembly to effectuate the skin to rib interface and the spar to rib interface, and which does not sacrifice wing stiffness. 
     The above objects are achieved by providing a method and apparatus of bonded wing construction in which skins having generally rhombus shaped protrusions are bonded to rib members having correspondingly shaped intrusions. The skins may also include triangular shaped protrusions which are bonded to K-shaped spars having correspondingly shaped intrusions. 
     The present invention has significant advantages, including: (1) only about 5% mechanical assembly; (2) less complex assembly; (3) a reduction in part counts, detail fabrication, assembly fastener installation, and associated assembly recurring costs; (4) a reduction in the complexity of assembly tool design and non-recurring tool procurement costs; and (5) reduction in skin manufacturing costs and cycle time. 
     The above objects and advantages, as well as others, will be evident from the following detailed description of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an assembly view of a prior-art wing structure. 
     FIGS. 2A and 2B are assembly views of the K-spar bonded structure configuration of the present invention. 
     FIG. 3 illustrates the bond socket concept of the present invention. 
     FIG. 4 is an enlarged view of the bond socket concept of FIG. 3 for a forward spar. 
     FIG. 5 is an enlarged view of the bond socket concept of FIG. 3 for an aft spar. 
     FIG. 6 is an assembly view of the K-spar bonded structure configuration of the present invention used in a torque box application. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1 in the drawings, a prior-art wing construction is illustrated. A rib  11  includes channels  13  into which are mechanically installed angle clips  15 . Angle clips  15  are mechanically coupled to I-beams  17  carried by an upper stiffened skin  19  and a lower stiffened skin  21 . A C-shaped spar  23  is coupled to rib  11  and/or upper and lower skins  19  and  21 . This is a typical mechanical assembly which requires a relatively large number of parts and which requires a complex assembly process. 
     Referring now to FIGS. 2A and 2B in the drawings, the K-spar bonded structure configuration of the present invention is illustrated. A rib  31  includes a plurality of generally rhombus shaped intrusions  33 . An upper stiffened skin  35  includes a plurality (only one shown) of generally correspondingly rhombus shaped protrusions  37  that are aligned with rib intrusions  33  on the upper surface of rib  31 . In a similar fashion, a lower stiffened skin  39  includes a plurality (only one shown) of generally correspondingly rhombus shaped protrusions  41  that are aligned with rib intrusions  33  on the lower surface of rib  31 . It should be understood that the geometric shape of the protrusions can vary widely from application to application. 
     A K-shaped spar, or K-spar,  51  is configured to conform to the end of rib  31 . As best seen in FIG. 2B, K-spar  51  is also wedge shaped in the vertical direction, having a protruding ridge  57  which mates with an intruding channel  59  in one or more ribs  31 . Upper skin  35  includes a triangular protrusion  53 . Likewise, lower skin  39  includes a triangular shaped protrusion  55 . K-spar  51  includes an upper triangular intrusion  61  and a lower triangular intrusion  63 . It should be understood that upper and lower triangular intrusions  61  and  63  may be of other shapes. 
     Skin  35  includes a tab portion  65 , and skin  39  includes a tab portion  67 . K-spar  51  includes corresponding upper and lower tab portions  69  and  71 . 
     When assembled and bonded together using conventional techniques and bonding materials, protrusions  37  on upper skin  35  and protrusions  41  on lower skin  39  interlockingly mate with intrusions  33  in rib  31 ; protrusions  53  on upper skin  35  and protrusions  55  on lower skin  39  interlockingly mate with upper intrusions  61  and lower intrusions  63 , respectively on K-spar  51 ; and tab portions  65  and  67  mate with tab portions  69  and  71 , respectively. Also, protruding ridges  57  interlockingly mate with channels  61 . This configuration provides large surface areas for which to bond these component parts together and create a stiff structure. This can be done with only about 5% mechanical assembly, as opposed to the 100% mechanical assembly associated with the prior art. 
     Referring now to FIG. 3 in the drawings, the assembled and bonded structure is illustrated. The bonding pattern is shown in bold. 
     Referring now to FIG. 4 in the drawings, an enlarged view of a forward K-spar and the bond socket concept according to the present invention is illustrated. The bonding pattern is shown in bold. 
     Referring now to FIG. 5 in the drawings, an enlarged view of a forward K-spar and the bond socket concept according to the present invention is illustrated. The bonding pattern is shown in bold. 
     It should be understood that the method of the present invention can be used to configure a wide variety of structures, not just aircraft wings. 
     Referring now to FIG. 6 in. the drawings, the present invention is illustrated in a torque box application. 
     The present invention has significant advantages, including: (1) only about 5% mechanical assembly; (2) less complex assembly; (3) a reduction in part counts, detail fabrication, assembly fastener installation, and associated assembly recurring costs; (4) a reduction in the complexity of assembly tool design and non-recurring tool procurement costs; and (5) reduction in skin manufacturing costs and cycle time. 
     Although the present invention is shown in a limited number of forms, it is not limited to just these forms, but is amenable to various changes and, modifications without departing from the spirit thereof.