Abstract:
An attachment device for an aircraft monument is disclosed having a pair of spaced apart parallel plates having vertical sides and a rounded upper surface defining an arch. A panel attaches the spaced apart parallel plates along an inner radius, and a pair of lugs including a vertical channel is disposed below the plates for receiving fasteners to connect the attachment device to a rail or planar surface.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. application Ser. No. 61/616,952, filed Mar. 28, 2012, the contents of which are incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Aircraft interior space is made up of various compartments, such as galleys, crew cabins, stowages, closets, lavatories, crew rest quarters, and other facility and storage monuments. These compartments of typically formed by partitions or structural units that separate one compartment from another. To meet airworthiness requirements on commercial passenger-carrying aircraft for the retention of compartments such as galleys attachment or connection devices must be used to secure them to the aircraft&#39;s airframe structure. Commonly, these take two forms: type one securing the lower section of the monument to the floor; and type two securing the upper section to the ceiling. Common practice is to manufacture these parts from a combination of aluminum, stainless steel and titanium. These attachments ultimately secure the monuments to the fuselage (or airframe), which may be by means of seat tracks, cross braces, floor beams and other subsidiary parts of the aircraft structure. 
         [0003]    Floor attachments normally connect to fixed locations, or “hard points,” within the cabin. These fittings do not allow relocation of the monuments to a new location, unless seat track mountings are used that allow either fore and aft movement, or lateral movement, along the track depending upon the orientation of the track. However, a full range of motion is typically unavailable for monument attachments in an aircraft. Floor attachments, or flutter points for low load bearing floor attachments, are typically bonded with glue and/or bolted to the monument as a secondary process, following manufacture of the monument&#39;s structural composite panel. Such an assembly typically uses a viscous liquid adhesive, and forms part of the basic monument structure. Due to the fact that only limited projection beyond the outer envelope of the monument is allowed, the floor fittings are commonly offset to the inside of the monument, and mounted on the composite panel&#39;s surface or through the panel to a greater or lesser degree, dependent upon design. Where variations exist in the position of the monument, or the position of the hard point attachments or seat tracks, the floor fitting has to be installed in that specific location during manufacture, and relocation or repositioning is limited and every orientation, change in monument location or change in foot print size requires a new location for the floor attachments as part of the structure. 
         [0004]    The existing monument attachment design leads to a bias stress loading to one skin of the composite panel, which often fails to optimize the load path into the structure and can lead to a requirement for additional reinforcement in the form of a metallic plate or “doubler” to help spread the stress more effectively throughout the monument and avoid stress concentrations. Unfortunately, this not only adds weight to the aircraft, but is an inefficient means to distribute the load. More recent floor attachment designs have required adjustment in the Z direction as well as the X and Y planes for purposes of alignment during the installation onto the aircraft, which increases the inward projection. 
         [0005]    On monuments such as galleys, this has led to a variation in the width of compartments in order that the wheels of the service carts or trolleys avoid contact with the inward projection of the floor fittings. This, in turn, does not allow standardization of cart bay doors, except for the widest possible dimension. This also impacts the efficiency of air circulation around carts in chilled compartments, and produces variations in the widths of standard guide or protection parts such as rub/bump strips in order to compensate for the different offsets. 
         [0006]    Additionally, with chilled or refrigerated galleys the presence of a sizable metallic component projecting through the cart bay wall produces significant undesirable cold bridges that can compromise the integrity of the chilled compartment, from a thermal resistance point of view, and the result is a failure to maintain the specified compartment temperature for maintaining perishable food stuffs during normal aircraft operations. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is an aircraft monument attachment device that maintains the airworthiness of floor attachments while eliminating some of the problems associated with current designs. Namely, a floor attachment is disclosed that is integrated into the interior of the monument&#39;s structural panel and may be installed during the primary manufacturing process (hot bonded) or as a post-process (cold bonded). This design offers several advantages over current conventional floor fittings. For one, the fitting eliminates the need for an offset and provides a more direct load path through the fitting and into the aircraft frame. Also, the projection of the fitting is significantly reduced, allowing standardization of cart compartment doors and standard guide/protection parts. This is because the fitting is located entirely or almost entirely within the composite panel of the monument, save a small portion of a collar or mounting ring. The fitting transfers load stresses into both skins of the composite panel, significantly improving the effectiveness of the load path. Where additional localized stiffening is required, extra plies of UD (uni-directional) fiber can be added to the composite sandwich as an integral part of the panel itself, or cold bonded non-metallic doublers can be added to one or both skins. 
         [0008]    The floor fitting can be pre-manufactured from aluminum, titanium, a reinforced, hardened plastic or carbon fiber, and either be machined, cast or injection molded depending on the calculated strength requirements and/or advances in material capabilities. An advantage of the present invention is that the fitting still allows X, Y and Z adjustment at monument installation but without significantly increasing inward floor fitting projection and without additional projection outside the galley envelope. 
         [0009]    The fitting may be manufactured to accommodate either single or twin bolt fixings as primary attachments. A low load flutter point or stabilizer fitting could also use the same manufacturing and bonding principles with the required limit on X, Y, or Z movement provisioned for. 
         [0010]    Other features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments in conjunction with the accompanying drawings, which illustrate, by way of example, the operation of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an elevated, perspective view of the attachment device of the present invention; 
           [0012]      FIG. 2  is the attachment device of  FIG. 1  installed in an aircraft monument; and 
           [0013]      FIG. 3  is an elevated, perspective view of an alternate embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]      FIG. 1  illustrates a first embodiment of a monument attachment device according to the present invention. The attachment device  10  comprises two horseshoe shaped plates  20  having an outer radius along the perimeter and an inner radius along the inner edge. The two plates  20  are joined together along the inner radius by a rigid panel  30 , such that there is an arcuate gap between the two plates  20 , and between the rigid panel  30  and the outer radius of the two plates  20 . The connection of the two plates to the rigid panel  30 , such as by welding or as a one piece casting or molding, for example, is sufficient to transfer loads from the panel  30  to the plates  20 . 
         [0015]    At the base of the attachment device  10  is a block  40  including a pair of lugs  45  formed in the block  40  to secure to the fitting to an attachment point on the aircraft. Each lug  45  includes a through hole  50  for receiving a fastener that fixes the block  40  and attachment device  10  to a transversely oriented rail  62  mounted on the floor or ceiling of the aircraft. Above the lug  45 , a hollowed cylindrical recess  72  may be formed in the block to provide clearance to insert a fastener, such that a neck  64  is created in the block  40  along an upper surface. The block  40  also includes a pair of holes  66  that can be used to secure the plates  20  to the block  40 . The bottom edge  70  of the plates  20  coincides with a bottom edge of the block  40  such that the attachment device lays flush with a floor of the aircraft. 
         [0016]    In  FIG. 2 , the attachment device  10  is integrally mounted into an aircraft monument  100  such as a stowage compartment, galley wall, or the like. A pair of composite panels  110  form the wall of the monument  100 , and sandwiched between the walls  110  is a composite panel core material  120  that forms the interior of the wall structure. At the base of the wall  100 , between the panels  110 , is the floor fitting  10  integrated into the wall structure and used to mount the wall  100  to the rail  62  along the floor of the aircraft. The rail  62  includes a series of circular slots or recesses  66  that receive the mounting rods or fasteners. The cooperation of the attachment device  10  and the rail  62  allow the monument  100  to be positioned along the rail easily and also allows the monument to be moved without damage to the floor or the monument. The window of the attachment device  10  provides a space above the cylindrical lugs  40  that can be used to insert and remove the fastener, and the arch shape of the fitting contributes to the overall strength of the fitting. 
         [0017]    In a preferred embodiment, the attachment device  10  is integrated in the wall structure of the monument  100  during the primary build phase, eliminating the need for a secondary operation and greatly improving the component strength and the ability of the structure to handle both static and dynamic loads. This is particularly important in a vehicle such as an aircraft, which is subject to dynamic loads on a consistent basis. The lug  40  creates a small offset that allow the monument structure to have a greater proportion of standardized parts while reducing the weight of the component as well as the footprint of the monument. In a non-metallic form, such as a composite or hardened plastic, the fitting  10  can be mass produced, very light, and resistant to corrosion. However, this does not preclude the post panel manufacturing process (e.g., pressed panels) cold bonding of either the single or twin bolt floor fitting. 
         [0018]    While the embodiment of  FIGS. 1 and 2  are particularly suited for aligning the monument transversely to the rail  62 , the embodiment of  FIG. 3  can be used to align the monument parallel to the rail  62 . The attachment device  200  has a “D” shaped outer member  210  comprising two parallel plates  215  extending from a rim  220 . The rim  220  is affixed to a beam  230  having a pair of holes arranged vertically through the beam. The beam  230  is mounted on a platform  240  having an elongated body  245  with circular ends  250 . Fasteners  260  pass through the platform  240  at the circular ends  250  to mount the attachment device  200  to the rail  62 . Another pair of fasteners  270  can be used to secure the attachment device  200  to the platform  240 , and can also be used to secure the platform  240  to the rail  62 . The attachment device  200  can be embedded or integrally formed into a monument  100  such that the monument can be attached to the rail  62  in a parallel configuration as shown in  FIG. 3 . 
         [0019]    An important consideration of the present invention is the ability to transfer both static and dynamic loads from the attachment device  10 ,  200  evenly into both skins of the structural panels  110 . When dynamic or static loading is created at the juncture between the fitting and the floor, the stress emanates from the areas adjacent the fastener and is directed outward toward the panels where it moves through the panels in roughly equal amounts. This distributed loading helps to keep the panel and the fitting at manageable stress levels and prolong the life of the fitting and the panel in the presences of static and dynamic loading. Where additional localized stiffening is required, extra plies of UD (uni-directional) fiber  140  can be added to the fitting to increase the strength of the attachment device  10 . Alternatively, or in addition to, carbon fiber doublers may be used to spread stress loads to a larger area of the structural panel skin. 
         [0020]    The present invention presents several benefits and improvements over existing monument fittings. One is that beverage cart bay offsets that are necessary to avoid the existing fitting projections can be eliminated. Another is that compartment door widths and other component sizes can be standardized. The overall width or centerline of the galley or monument is reduced. In the case of chilled cart (or trolley) compartments, cold bridging through the floor fittings are virtually eliminated. The fitting itself can be the subject of mass production techniques as the component is standardized, such as injection molding, compression molding, and the like. Additionally, long term problems caused by corrosion of the metallic attachment are virtually eliminated since the fitting is largely shielded by the wall panels. 
         [0021]    Although the foregoing descriptions and accompanying drawings are intended to set forth the inventor&#39;s best mode, it is to be understood that the invention may be embodied in other forms without departure from the benefits and characteristics described and depicted. the embodiments described therefore are to be considered in all respects as illustrative and not restrictive. Although the present invention has been described in terms of certain preferred embodiments, other embodiments that are apparent to those of ordinary skill in the art are also within the scope of the present invention.