Abstract:
An equipment rack fabricated from C-channel, flat plate and mechanical fasteners for installation and support of new or retrofit antenna equipment on wide body aircraft. The rack provides direct mechanical connection to aircraft structure, eliminating multipiece turnbuckle assemblies. Vertical rails and support braces each attach at a first end to a combination of flat plates and drip shields, the flat plates and drip shields supporting the antenna equipment. A second end of each vertical rail and support brace attaches directly to aircraft structure by mechanical fasteners. The equipment rack design provides a minimal part design, providing a lower cost for both the equipment rack and its installation.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to the design, construction and installation of an equipment rack, and more particularly to the design, construction, and installation of an equipment rack supporting an antenna subsystem of a wide body aircraft.  
         BACKGROUND OF THE INVENTION  
         [0002]    The aircraft industry currently employs overhead racks normally attached to frames or frame structure to support systems and components adjacent to the frames of the aircraft. These racks are typically installed and attached to the frames or frame structure using adjustable mounts similar to turnbuckle assemblies which are purchased from outside vendors and utilized to provide position adjustment of the racks. For existing aircraft, system changes or new developments in the industry may require that new equipment be retrofitted in the aircraft adjacent to the frame structure. The new equipment may encounter items that were originally installed or also retrofitted after initial construction of the aircraft. There is a need for a simpler, less expensive system to retrofit equipment racks onto existing aircraft, particularly for operation in connection with new antennas installed on the aircraft.  
           [0003]    The existing turnbuckle assembly used in present day aircraft applications typically employs a support member such as a vertical rail or diagonal brace, fixedly attached at a first end to the rack assembly, and a second end attached to a turnbuckle assembly having both a support member attachment end and a free end. The turnbuckle assembly free end in turn is attached to the aircraft structure via a cast or forged mounting pad, typically by a mechanical bolt or pin. The mount pad requires separate attachment to the aircraft structure, such structure typically being a frame or intercostal, by mechanical fastener means. This multi-piece assembly requires several fastener installation steps and an accurate location of the mount pad for the free end of the turnbuckle. If the mount pad is misaligned during initial installation, the turnbuckle and therefore the overhead rack installation process comes to a halt until either the rack arrangement or the mount pad can be relocated. This involves a significant time loss and a potential for mislocation of the overhead racks.  
           [0004]    On wide body aircraft, two antennas are intended for retrofit on existing aircraft and proposed for installation on new aircraft. An overhead rack assembly is required to support the antenna drive system converter and power supply. This assembly must be located within about two (2) feet (0.61 meters) of each antenna. Due to the tight location spacing requirement, and the possibility of encountering existing or other retrofitted equipment adjacent to the antenna installation location(s), an alternative to the turnbuckle assembly to support the equipment rack(s) is needed. A simpler design requiring fewer parts, less expense, more rapid installation, and greater location flexibility of the equipment rack(s) is therefore required.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention addresses these and other drawbacks by providing a rack which is supported to the structure of the aircraft by the rigid structure of the rack itself. The equipment rack of the invention includes sheet metal, channel bracket and U-channel shaped members. One or a combination of threaded fasteners, rivets, or hole filling fittings are employed to install the rack assembly aboard the aircraft. In one embodiment of the invention, the assembly consists of several plates providing support for the antenna assembly equipment. The plates are supported by vertical members which attach directly to intercostals spanning between individual frames stringers(?) of the aircraft. Two sets of braces are then employed to diagonally support and restrain the assembly, each set positioned to restrain motion of the rack about a 90 degree axis. A first set of braces is employed to restrain forward/aft motion of the rack. This first set of braces attach to the lower rack area and extend diagonally upward to an intercostal. A second set of braces is employed to restrain inboard/outboard motion of the rack. This second set of braces attach in a perpendicular direction to the first set of braces. This second set of braces connect the lower rack assembly to the aircraft frames.  
           [0006]    The use of U-shaped channels and flat plate for braces and bracket assemblies permit the preassembly of a rack with dimensions suitable for the location. Elimination of the multi-part turnbuckle assembly permits the assembler or installer to make modifications as required in the field. Modifications required for installation of the present invention consist of making simple cuts in the vertical rails or diagonal braces to vary the height or location of the rack(s), rather than the complicated use of the turnbuckle assemblies previously used.  
           [0007]    In another aspect of this invention, additional support plates comprising a drip shield comprising a predominantly flat plate can be installed, which protects the electrical equipment installed on the rack and provides additional stiffness to the rack.  
           [0008]    The present invention provides several advantages over the industry standard rack design. One advantage is the installer can locally make modifications quickly and inexpensively by simple material cut(s). Another advantage of the invention is to provide flexibility to locate the antenna equipment to suit existing installations. Yet another advantage of the invention is that racks can be preassembled and shipped to other installers or backfitters of aircraft equipment. Flexibility to account for different aircraft arrangements can also be provided for by utilizing assembly pieces of greater length than normally required for this type of an assembly. Field modification of the various parts including the diagonal braces and vertical support members can be made easily by an installer in the field.  
           [0009]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The various advantages of the present invention will become apparent to one skilled in the art by reading the following specification and subjoined claims and by referencing the following drawings in which:  
         [0011]    [0011]FIG. 1 is an perspective view showing the overall assembly of a typical rack in accordance with one aspect of the present invention;  
         [0012]    [0012]FIG. 2 is an elevational view looking aft of the assembly of FIG. 1;  
         [0013]    [0013]FIG. 3 is a side view looking outboard taken along Section line III-III of FIG. 2;  
         [0014]    [0014]FIG. 4 is an exploded perspective view of a turnbuckle rack design, wherein the bracket assembly for the turnbuckle is mounted on a frame of an aircraft; and  
         [0015]    [0015]FIG. 5 is an exploded perspective view of the turnbuckle rack design of FIG. 4 showing an alternate turnbuckle assembly mounted to an intercostal. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]    The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Referring to FIG. 1, a rack assembly in accordance with a preferred embodiment of the present invention is shown. Rack assembly  100  comprises a vertical rail  102  arranged to support each corner of drip shield  104  and lower platform  106 . Each vertical rail  102  comprises a rigid structural shape such as a U-channel, L-channel, or that of a rectangle. Drip shield  104  and lower platform  106  are plates which may be of any shape suitable for the equipment supported, and are generally square or rectangular in shape, and may have additional support members or edge bends for stiffness. At least one and preferably two horizontal supports  108  , each of the horizontal supports  108  having a similar shape to the vertical rail  102  shape, are spaced to support the widest dimension required for the equipment. An upper end  110  of each vertical rail  102  is fastened to either an outboard intercostal  112  or an inboard intercostal  114 . Attachment of vertical rail  102  upper end  110  to outboard intercostal  112  or inboard intercostal  114  is by fasteners  116  direct to the intercostal(s), but may also be via a combination of fasteners  116  and angle brackets  118 . A variety of fasteners  116  may be employed including screw type connectors, rivets, and hole filling fittings.  
         [0017]    Referring now to FIG. 2, a view looking aft in a typical wide body aircraft is provided, showing a rack assembly of the present invention. FIG. 2 provides rack assembly  100 , and an exemplary arrangement of equipment supported by a rack of the present invention. This equipment comprises at least a displacement converter  120  and a power supply  122 . Dimension “A” is the rack width, controlled to provide a rack assembly width which provides the minimum space for the displacement converter  120  and the power supply  122 . Dimension “B” represents the length of each inboard (long) vertical rail  102 . Dimension “C” represents the length of each outboard (short) vertical rail  102 . Dimension “B” and dimension “C” will vary for different rack installations and from aircraft to aircraft, therefore it is preferable to provide each vertical rail  102  with additional length which can be modified to suit installation and aircraft design tolerances.  
         [0018]    Rack assembly  100  is supported from aircraft frame structure, such as frame  124  shown in FIG. 2. At least a pair of diagonal braces  126  comprising forward brace  128  and aft brace  130  (shown in FIG. 3) each diagonally support rack assembly  100  to an existing intercostal. Alternatively, an intercostal  131  is added for this purpose as shown in FIG. 1. Forward brace  128  and aft brace  130  provide inboard/outboard restraint of motion of rack assembly  100 . Forward brace  128  and aft brace  130  are typically mechanically fastened at opposing ends of both braces to both rack assembly  100  and an intercostal, and are discussed in greater detail below.  
         [0019]    Referring now to FIG. 3, frame  124  and adjacent frame  136  are shown, as are typical intercostals including outboard intercostal  112  and inboard intercostal  114 . Outboard intercostal  112  and inboard intercostal  114  are both perpendicularly joined at an end of each intercostal to frame  124  and adjacent frame  136  by mechanical fasteners  116  and angle brackets  118 . Inboard diagonal brace  138  joins the inboard forward corner of rack assembly  100  to inboard intercostal  114 . Outboard diagonal brace  140 , shown in FIG. 1, joins the outboard forward corner of rack assembly  100  to outboard intercostal  112 . Inboard diagonal brace  138  and outboard diagonal brace  140 , respectively, are positioned about  90  degrees from the orientation of forward brace  128  and aft brace  130 , to restrain forward/aft motion of rack assembly  100 .  
         [0020]    Also shown in FIG. 3, Dimension “D” represents an example intercostal length. Intercostal length is determined by the spacing between frames which may vary from aircraft to aircraft or by aircraft section.  
         [0021]    Referring to FIG. 4, support assembly  200 , currently used by the aircraft industry to provide support of equipment to aircraft support structure, is shown. Frame  202  is a typical aircraft frame. Brace  204  is attached to the rack assembly (not shown). Turnbuckle  206  is attached at a first end to brace  204 . A second end of turnbuckle  206  is attached to bracket  208 . Bracket  208  is installed using mechanical fasteners to frame  202 . The assembly of turnbuckle  206  to bracket  208  employs mechanical fasteners such as bolt  210  and nut  212 , respectfully.  
         [0022]    Referring to FIG. 5, an alternate configuration to support assembly  200  is shown with the turnbuckle assembly joining a rack to an intercostal of the aircraft. Support assembly  300  comprises a typical frame  302 , brace  304  (similar to brace  204 ), a turnbuckle  306  (similar to turnbuckle  206 ) and a bracket  308  (similar to bracket  208 ). Fasteners comprising bolt  310  and nut  312  join turnbuckle  306  to bracket  308 . Bracket  308  in this configuration is shown attached to intercostal  314  using mechanical fasteners  316 . FIG. 5 also shows an angle bracket  318  typically used to join intercostal  314  to frame  302 . Angle bracket  318  is fixedly attached to intercostal  314  with mechanical fasteners  320 .  
         [0023]    A key function of the invention is to provide the ability to locate the rack assembly  100  in close proximity, typically within two feet, of the antennas. The invention is suitable for use in wide body aircraft having sufficient vertical height in the overhead to accommodate the rack assembly. Typically two antennas are employed per plane, requiring at least two rack assemblies  100  per plane.  
         [0024]    Previous attachment designs, support assembly  200  of FIG. 4, and support assembly  300  of FIG. 5, respectively, required pre-location of mount bracket  208  or mount bracket  308 . Improper alignment of a mount bracket would preclude or delay rack installation. Additionally, the expense and assembly time associated with turnbuckle  206  or turnbuckle  306  installation is precluded by the invention use of direct fastening of the vertical rails and diagonal and forward braces to the plane structure.  
         [0025]    Each vertical rail  102  may be precut to known dimension, or provided with additional stock length. This extra stock length may be easily removed to suit an existing installation space or interference with surrounding equipment or structure.  
         [0026]    Referring back to FIGS. 1, 2 and  3 , the mechanical fastening method for the invention is also shown. At least one clearance hole  142  is provided in each vertical rail  102  upper end  110  for mechanical fastener throughput. Mechanical fasteners  116  are each inserted through a clearance hole  142  to meet with either a pre-tapped or preformed mating hole  146  provided in inboard intercostal  114 , outboard intercostal  112 , frame  124  or frame  136 . An angle bracket  118  may also be employed as required between each vertical rail  102  upper end  110  and inboard intercostal  1 . 14 , outboard intercostal  112 , frame  124  or frame  136 .  
         [0027]    At least a pair of diagonal braces  126 , comprising forward brace  128 , and aft brace  130 , are attached in a similar manner as each vertical rail  102 . Specifically, a first end of forward brace  128  is attached at the lower, forward, outboard corner of rack assembly  100 , and a first end of aft brace  130  is attached at the lower, aft, outboard corner of rack assembly  100 . A second end of forward brace  128  and a second end of aft brace  130  are each preferably connected to an existing intercostal (not shown), or a new intercostal  131  is added for this purpose, as shown in FIG. 1.  
         [0028]    A first end of inboard diagonal brace  138  connects at the inboard, lower aft corner of rack assembly  100 , and a first end of outboard diagonal brace  140  connects at the outboard, lower aft corner of rack assembly  100 . A second end of inboard diagonal brace  138 , and a second end of outboard diagonal brace  140  each connect to intercostals existing or added for this purpose in the aircraft. The preferred method is to attach the second end of inboard diagonal brace  138  to inboard intercostal  114 , and the second end of outboard diagonal brace  140  to outboard intercostal  112 .  
         [0029]    The invention provides the advantages of a simpler equipment rack design, having fewer attachment parts, which in turn both reduces installation time and permits on-site adjustment for aircraft construction conditions. The invention also permits pre-construction of equipment racks off-site for shipment to refit facilities.  
         [0030]    Those skilled in the art can now appreciate from the foregoing description that the teaching of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification, and following claims.  
         [0031]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.