Abstract:
An air cushion cargo shuttle for loading and unloading cargo on an airplane is described. The air cushion cargo shuttle includes a first inner air curtain defining a first volume of pressurized air. The air cushion cargo shuttle also includes a noise barrier curtain enclosing the first inner air curtain. The noise barrier curtain is adapted to trap air leaking from the first inner air curtain.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a division of application serial number U.S. Ser. No. 14/512,118 filed Oct. 10, 2014 for NOISE REDUCTION BARRIER FOR AIR CUSHION SUPPORTED AIRCRAFT CARGO LOADING ROBOT. 
     
    
     FIELD 
       [0002]    The present disclosure relates generally to cargo management systems. 
       BACKGROUND 
       [0003]    Conventional aircraft cargo systems typically include various tracks and rollers that span the length of an aircraft. Power drive units (“PDUs”) convey cargo forward and aft along the aircraft on conveyance rollers which are attached to the aircraft floor structure. Cargo may be loaded from an aft position on an aircraft and conducted by the cargo system to a forward position and/or, depending upon aircraft configuration, cargo may be loaded from a forward position on an aircraft and conducted by the cargo system to an aft position. Conventional systems are typically designed to accommodate a particular pallet size. Conventional systems are typically comprised of numerous components that may be time consuming to install, replace and maintain. 
       SUMMARY 
       [0004]    The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting. 
         [0005]    An air cushion cargo shuttle for loading and unloading cargo on an airplane is described. The air cushion cargo shuttle includes a first inner air curtain defining a first volume of pressurized air. The air cushion cargo shuttle also includes a noise barrier curtain enclosing the first inner air curtain. The noise barrier curtain is adapted to trap air leaking from the first inner air curtain. 
         [0006]    Also described is a method for preventing leakage air from escaping an air cushion cargo shuttle. The air cushion cargo shuttle has an inner air curtain that forms a volume of pressurized air underneath the air cushion cargo shuttle. The method includes providing a noise barrier curtain that encloses the inner air curtain. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures. 
           [0008]      FIG. 1  illustrates an air cushion cargo shuttle on a floor panel, in accordance with various embodiments; 
           [0009]      FIG. 2  illustrates an air cushion cargo shuttle from a view underneath the air cushion cargo shuttle, in accordance with various embodiments; 
           [0010]      FIG. 3  illustrates a bottom view of a portion of a volume of an air cushion cargo shuttle, in accordance with various embodiments; 
           [0011]      FIG. 4  illustrates a cross-sectional view of an air cushion cargo shuttle  100  along a line A-A′ illustrated in  FIG. 3 , in accordance with various embodiments; and 
           [0012]      FIG. 5  illustrates a cross-sectional view of a noise barrier curtain including multiple materials, in accordance with various embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the spirit and scope of the disclosure. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected, or the like may include permanent, removable, temporary, partial, full, and/or any other possible attachment option. 
         [0014]    As used herein, “aft” refers to the direction associated with the tail of an aircraft, or generally, to the direction of exhaust of the gas turbine. As used herein, “forward” refers to the direction associated with the nose of an aircraft, or generally, to the direction of flight or motion. 
         [0015]    Aircraft cargo management systems as disclosed herein allow cargo to be loaded into an aircraft and positioned within the aircraft in a simple, elegant manner. In that regard, aircraft cargo management systems as disclosed herein may reduce part count and associated replacement/wear costs over time. 
         [0016]      FIG. 1  illustrates an air cushion cargo shuttle  100  on a floor panel  112 . Air cushion cargo shuttle  100  is designed to lift above floor panel  112  by increasing air pressure underneath air cushion cargo shuttle  100  within perimeter  110 . The pressurized air underneath air cushion cargo shuttle  100  counteracts gravitational pull on air cushion cargo shuttle  100 , thus raising air cushion cargo shuttle  100  off floor panel  112 . 
         [0017]    Air cushion cargo shuttle  100  includes four volumes  102 . In various embodiments, air cushion cargo shuttle can include any number of volumes. Volume  102 A includes a centrifugal air blower (also referred to as an air blower)  106 A. Inlet  114 A is adapted to receive air external to air cushion cargo shuttle  100 . Air blower  106 A receives air from inlet  114 A and blows the air into volume  102 A, increasing the air pressure in volume  102 A. The amount of air that flows through air blower  106 A is controlled by centrifugal air blower controller (also referred to as a controller)  104 A. 
         [0018]    Each of the four volumes  102  includes an air blower  106  connected to an inlet  114  and a controller  104 . The air pressure under each volume  102  (e.g., volume  102 A) may be different than the air pressure under the other volumes  102  (e.g., volume  102 B,  102 C and  102 D). This allows air cushion cargo shuttle  100  to provide different amounts of upward force (i.e., force in the positive Z direction) throughout air cushion cargo shuttle  100  to account for unbalanced cargo. 
         [0019]    In  FIG. 1 , a top surface  101  of air cushion cargo shuttle  100  is transparent. Top surface  101  is positioned at the top of air cushion cargo shuttle  100  and is adapted to receive cargo. Top surface  101  is positioned at the farthest end of air cushion cargo shuttle  100  in the positive Z direction. 
         [0020]      FIG. 2  illustrates air cushion cargo shuttle  100  from a view underneath air cushion cargo shuttle  100 . An X-Y-Z axis is illustrated, where the negative Z axis is illustrated extending from the bottom of air cushion cargo shuttle  100  and the positive Z direction extends from the top of air cushion cargo shuttle  100 . Air blower  106 A is attached to an inlet duct  204 A which receives air from inlet  114 A. Air blower  106 A is also attached to controller  104 A which controls the amount of air moved by air blower  106 A. 
         [0021]    When air cushion cargo shuttle  100  is in an upright position (i.e., top plate  101  is farthest upward, in the positive Z direction), volumes  102  may be filled with pressurized air. This pressurized air may cause air cushion cargo shuttle  100  to lift above floor panel  112 . As illustrated, volume  102 A is enclosed by a pressure compensated air curtain  202 A. Pressure compensated air curtain  202 A is adapted to keep pressurized air from escaping volume  102 A. When air cushion cargo shuttle  100  is lifted above floor panel  112 , pressure compensated air curtain  202 A extends towards and contacts floor panel  112 . In order to maintain contact with floor panel  112  so that pressurized air does not escape volume  102 A, force may be exerted on pressure compensated air curtain  202 A. This force is provided by springs between air cushion cargo shuttle  100  and floor panel  112  and is backed by air pressure in volume  102 A. By using pressurized air as an additional downward force (i.e., in the negative Z direction) to push pressure compensated air curtain  202 A against floor panel  112 , the higher the air pressure in volume  102 A is, the more force is exerted from pressure compensated air curtain  202 A to floor panel  112 . This forms a seal between pressure compensated air curtain  202 A and floor panel  112 . 
         [0022]    In various embodiments, volume  102 A may include air pressurized at a pressure between 0 pounds per square inch (psi) (˜27.5 kPa) and 4 psi. Even though pressure compensated air curtain  202 A is sealed against floor panel  112  by spring force as well as pressure compensated force, some air leakage may still occur. This leakage air may be traveling at a high velocity, resulting in an undesirably loud sound. On cargo aircraft, this loud sound may be unpleasant for operators. On passenger aircraft, this loud sound may be unpleasant for operators as well as airline passengers. 
         [0023]    Volume  102 A includes air blower  106 A for blowing air from inlet  114 A into volume  102 A. Pressure compensated air curtain  202 A prevents the air blown into volume  102 A from escaping. Together, air blower  106 A and pressure compensated air curtain  202 A can cause air pressure in volume  102 A to increase. Volume  102 B,  102 C and  102 D can be pressurized in the same fashion using pressure compensated air curtain  202 B,  202 C and  202 D, and air blower  106 B,  106 C and  106 D. 
         [0024]    Within the perimeter  110  of air cushion cargo shuttle  100 , a noise barrier curtain  205  is positioned. Noise barrier curtain  205  encloses all volumes  102  as well as pressure compensated air curtains  202 . Noise barrier curtains  204  are considered to be downstream with respect to pressure from the pressure compensated air curtains  202 . Air that leaks through any pressure compensated air curtain  202  will be prevented from escaping air cushion cargo shuttle  100  by noise barrier curtain  205 . Noise barrier curtain  205  may direct air that escapes from volumes  102  back towards an inlet  114 . By redirecting the leakage air, noise barrier curtain  205  dissipates the sound of the high velocity leakage air. 
         [0025]    If excessive or prolonged friction occurs between noise barrier curtain  205  and floor panel  112 , then noise barrier curtain  205  and/or floor panel  112  may wear out. It is therefore desirable that noise barrier curtain  205  be friction resistant. Noise barrier curtain  205  may be made from a friction resistant polymer, such as polytetrafluoroethylene (PTFE) (available under the trademark TEFLON), natural and/or synthetic rubber, fiber-reinforced PTFE, and other suitable materials. In various embodiments, noise barrier curtain  205  may include multiple materials. 
         [0026]      FIG. 5  illustrates a cross-sectional view of noise barrier curtain  205  including multiple materials. Noise barrier curtain  205  may include a backing  500 , which may be stiff. Backing  500  may allow a portion of noise barrier curtain to be rigid. Backing  500  may be, for example, springy foam, a spring or springs, etc. Backing  500  may be surrounded with a contact surface  502 . Contact surface  502  may be made from a friction resistant polymer, such as PTFE, rubber, fiber-reinforced PTFE, etc. In various embodiments, contact surface  502  may be soft as well as friction resistant. In this regard, the term “soft” in this context only may mean that contact surface  502  is not difficult to mold, compress and/or fold. Because contact surface  502  is friction resistant, friction between floor panel  112  and contact surface  502  may cause reduced wear on noise barrier curtain  205  and/or floor panel  112 . 
         [0027]    As well as acting as a noise barrier against air leakage from pressure compensated air curtains  202 , noise barrier curtain  205  may keep debris from collecting on floor panel  112  and from reaching pressure compensated air curtains  202 . As air cushion cargo shuttle travels over floor panel  112 , noise barrier curtain  205  may collect debris and transport it to the aft or forward end of the cargo bay. This debris may then be swept away after it has been collected by noise barrier curtain  205 . By removing debris, noise barrier curtain  205  keeps abrasive particles from causing wear to pressure compensated air curtains  202 , and reduces cleaning times and costs of the aircraft. 
         [0028]    In various embodiments, only one noise barrier curtain  205  is utilized in air cushion cargo shuttle. In preferred embodiments, noise barrier curtain  205  is positioned near the perimeter  110  of air cushion cargo shuttle  100 , so as to enclose all volumes  102 . Because noise barrier curtain  205  traps air leaking from all volumes  102  and redirects it towards an inlet  114 , leakage air may not create a noise problem. 
         [0029]      FIG. 3  illustrates a bottom view of a portion of volume  102 A of air cushion cargo shuttle  100 .  FIG. 3  illustrates that pressure compensated air curtain  202 A is positioned within noise barrier curtain  205 , which is positioned within perimeter  110 . 
         [0030]      FIG. 4  illustrates a cross-sectional view of air cushion cargo shuttle  100  along line A-A′ from  FIG. 3 . The X-Y-Z axis is shown to illustrate relative position of components. Inlet  114 A is illustrated on the side of air cushion cargo shuttle  100 . Air enters air cushion cargo shuttle  100  through inlet  114 A where it travels through inlet duct  204 A towards air blower  106 A. Air blower  106 A then blows air from inlet  114 A into volume  102 A. An amount of air inside of volume  102 A then increases, resulting in higher air pressure within volume  102 A. 
         [0031]    As previously mentioned, some air may leak from volume  102 A. Leakage air is illustrated by arrows  414 . Most air within volume  102 A is contained by pressure compensated air curtain  202 A. Pressure compensated air curtain  202 A forms a contact point  400  with floor panel  112 . A spring  404  pushes pressure compensated air curtain  202 A towards floor panel  112 . In various embodiments, spring  404  may be a wave spring, coil springs, springy foam or the like. Pressurized air also exerts additional force on pressure compensated air curtain  202 A via pressure supply hole  406 . 
         [0032]    Pressure compensated air curtain  202 A is designed to keep pressurized air from escaping volume  102 A. However, as indicated by arrows  414 , some air may still escape pressure compensated air curtain  202 A. Noise barrier curtain  205  is adapted to contain this leakage air. Noise barrier curtain  205  includes a spring  410  above noise barrier curtain  205 . Spring  410  exerts force onto the top (i.e., exerts force in the negative Z direction) of noise barrier curtain  205 , thus forming a seal between noise barrier curtain  205  and floor panel  112  at contact point  402 . Generally, air between noise barrier curtain  205  and volume  102 A will not be highly pressurized. Air pressure between noise barrier curtain  205  and pressure compensated air curtain  202 A is substantially the same as the air pressure in air passage  408 , which is approximately zero psi relative to the ambient pressure. Therefore, spring  410  exerts sufficient force on noise barrier curtain  205  to prevent leakage air from escaping noise barrier curtain  205 . 
         [0033]    Leakage air from volume  102 A is then directed towards inlet  114 A. Air passage  408  exists between noise barrier curtain  205  and inlet  114 A. Leakage air, as indicated by arrows  414 , travels through air passage  408  after it is stopped by noise barrier curtain  205 . This leakage air is then channeled towards inlet duct  204 A where it joins air from inlet  114 A. By allowing leakage air to be sucked back into inlet duct  204 A, noise created from high velocity leakage air past pressure compensated air curtain  202 A is reduced or removed. 
         [0034]    Noise barrier curtain  205  is adapted to move parallel to the Z axis within air cushion cargo shuttle  100 . This is to allow noise barrier curtain  205  to remain in contact with floor panel  112  when air cushion cargo shuttle  100  is lifted above floor panel  112 . 
         [0035]    Noise barrier curtain  205  includes a lip  418 . Air cushion cargo shuttle  100  also includes a lip  416 . Lip  416  and lip  418  are adapted to prevent noise barrier curtain  205  from extending too far in the negative Z direction from air cushion cargo shuttle  100 . Noise barrier curtain  205  is adapted to extend outward towards floor panel  112  (in the negative Z direction) for a distance  420  between lip  418  and lip  416 . When lip  418  meets lip  416 , noise barrier curtain  205  can extend no further towards floor panel  112 . Distance  420  may be, for example, one quarter of an inch or less. Because floor panel  112  will preferably be flat and smooth, it is not necessary for air cushion cargo shuttle  100  to be raised much above floor panel  112 . A quarter of an inch is generally sufficient lift for air cushion cargo shuttle  100  to travel across floor panel  112 . 
         [0036]    Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials. 
         [0037]    Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment”, “an embodiment”, “various embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
         [0038]    Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.