Abstract:
The present disclosure includes cargo loading systems and components including cargo systems utilizing one or more air cushions to elevate one or more cargo shuttles. Air is delivered to the air cushions by compact centrifugal air blowers. Such compact centrifugal air blowers are designed to provide sufficient power to inflate air cushions, while having a sufficiently short profile.

Description:
FIELD 
     The present disclosure relates generally to cargo loading systems and, more specifically, to cargo loading systems utilizing compact centrifugal air blowers. 
     BACKGROUND 
     Conventional aircraft cargo systems typically include various tracks and rollers that span the length of an aircraft. 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 
     A cargo loading system in accordance with the present disclosure may comprise a cargo shuttle having a frame, an air cushion located beneath the cargo shuttle, a compact centrifugal air blower positioned within the frame of the cargo shuttle and comprising an outlet in fluid communication with the air cushion, a stator integrated into a first heat diffuser, and a magnet concentrically surrounding the stator. The compact centrifugal air blower may include impeller concentrically surrounding the stator and physically coupled to the magnet. The outlet and/or inlet may be perpendicular to the stator. The compact centrifugal air blower may pump air into the air cushion at a rate between about 6 kPa and about 70 kPa. The height of the compact centrifugal air blower may be between about 25 mm and about 50 mm. The impeller may be concentrically surrounded by a second heat diffuser. 
     A compact centrifugal air blower in accordance with the present disclosure may comprise an outlet in fluid communication with an air cushion, a stator integrated into a first heat diffuser, an impeller concentrically surrounding the stator, wherein a magnet is physically coupled to the impeller, and a second heat diffuser concentrically surrounding the impeller. The outlet may be perpendicular to the stator. The blower may include an inlet perpendicular to the stator. Further, the compact centrifugal air blower may pump air into the air cushion at a rate between about 6 kPa and about 70 kPa and a height of the compact centrifugal air blower is between about 25 mm and about 50 mm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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, wherein like numerals denote like elements. 
         FIG. 1  illustrates a portion of a cargo management system, in accordance with the present disclosure; 
         FIG. 2  illustrates a portion of a cargo management system, in accordance with the present disclosure; 
         FIG. 3  illustrates a portion of a cargo management system, in accordance with the present disclosure; 
         FIG. 4  illustrates a portion of a cargo management system, in accordance with the present disclosure; and 
         FIGS. 5A and 5B  illustrate, respectively, a perspective view and a cross-sectional view of a compact centrifugal blower, in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description of embodiments herein makes reference to the accompanying drawings, which show embodiments by way of illustration. While these embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical and mechanical changes may be made without departing from the spirit and scope of the inventions. Thus, the detailed description herein is presented for purposes of illustration only and not for limitation. For example, 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. 
     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. 
     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. 
     Cargo loading systems of the present disclosure comprise one or more compact centrifugal air blowers which provide air to air cushions to elevate one or more cargo shuttles. The compact nature of the air blowers allows for improved fitment within an aircraft cargo area. 
     With reference to  FIGS. 1 and 2 , an aircraft cargo management system  100  in accordance with the present disclosure is illustrated using an x, y, and z axes for ease of illustration. Air cushion cargo shuttle  114  and  116  are shown forward of an aft portion of an aircraft. In various embodiments, air cushion cargo shuttle  114  may be coupled to an aft drive shuttle belt  106  and air cushion cargo shuttle  116  may be coupled to an aft drive shuttle belt  108 . Aft drive shuttle belt  106  is coupled to an aft drive shuttle unit  102 , and aft drive shuttle belt  108  is coupled to an aft drive shuttle unit  104 . 
     In various embodiments, a floor panel  112  is positioned beneath air cushion cargo shuttle  114 . Similarly, a floor panel  150  may be positioned beneath air cushion cargo shuttle  116 . As used with respect to air cushion cargo shuttle  114  and  116 , the term “beneath” may refer to the negative z direction. As used with respect to air cushion cargo shuttle  114  and  116 , the term “above” may refer to the positive z direction. In various embodiments, support rails  222  and  224  are laterally adjacent to floor panels  112  and  150 , and may be mounted to another aircraft component, such as an airframe, and may be capable of supporting the weight of cargo. Floor panel  112  may comprise at least one of a composite material or a metallic material. 
     Air cushion cargo shuttle  114  may, for example, be coupled to forward drive shuttle belt  208  and air cushion cargo shuttle  116  is coupled to forward drive shuttle belt  218 . Forward drive shuttle belt  208  is coupled to forward shuttle drive unit  204 . Forward drive shuttle belt  218  is coupled to forward shuttle drive unit  220 . Cargo  202  is shown as resting on support rails  222  and cargo  201  is shown as resting on support rails  224 . In various embodiments, cargo shuttle  116  may be used to lift cargo  201  off support rails  224  in the positive z direction and move cargo  201  forward or aft. 
     Forward drive shuttle belt  208 , forward drive shuttle belt  218 , aft drive shuttle belt  106 , and aft drive shuttle belt  108  (collectively, a “shuttle belt”) may comprise any suitable belt capable of pulling an air cushion cargo shuttle. For example, a shuttle belt may comprise a flat belt. In that regard, a flat shuttle belt may not occupy excess space along the z direction. For example, a shuttle belt may comprise a polyurethane coated belt that includes a communications and power bus. In that regard, the structural support and power/data functions are provided by a single shuttle belt structure. For example, in various embodiments, a shuttle belt may comprise steel wires oriented in parallel and coated with polyurethane to hold the steel wires together, provide anti-friction properties, and noise dampening properties. Among the steel wires may be copper wires or other wires that are capable of carrying an electrical current at any suitable voltage. In that regard, the shuttle belt may comprise one or more copper wires to carry high voltage power and/or low voltage electrical signals that may convey data. 
     The shuttle belts may be wound around a portion of forward shuttle drive unit  204 , forward shuttle drive unit  220 , aft drive shuttle unit  102  and aft drive shuttle unit  104  (collectively, “shuttle drive unit”). In that regard, a shuttle drive unit may comprise a cylindrical structure (e.g., a bobbin) to which a shuttle belt is affixed. The shuttle drive unit comprises a motive device, such as an electric motor, to rotate the bobbin in a desired direction. 
     With reference to  FIGS. 3 and 4 , air cushion cargo shuttle  114  may further comprise an air cushion  330  positioned beneath air cushion cargo shuttle  114 . It should be understood that air cushion cargo shuttle  116  is similarly structured and thus the features discussed herein relative to air cushion cargo shuttle  114  are also applicable to air cushion cargo shuttle  116 . Air cushion  330  is in fluid communication with an outlet of a centrifugal air blower  304 . In that regard, centrifugal air blower  304  may blow air beneath air cushion cargo shuttle  114  and, more specifically, into volume  302 . Volume  302  is shown in proximity to floor panel  112 . 
     Centrifugal air blower  304  is shown located beneath air cushion cargo shuttle  114 . Air cushion cargo shuttle  114  may comprise one or more centrifugal air blowers. In various embodiments, centrifugal air blower  304  is a compact air blower designed to fit entirely and/or at least partially beneath air cushion cargo shuttle  114  and within air cushion  330 . For example, centrifugal air blower  304  may comprise a height  520  (with momentary reference to  FIG. 5B ) that is equal to or less than the height (measured along the z axis) of air cushion  330 . For example, the height along the z axis of the air cushion  330  may be about 2 inches. In such embodiments, height  520  of air cushion cargo shuttle  114  may be less than about 2 inches. In various embodiments, height  520  of air blower  304  may be between 1 inch (25 mm) to 5 inches (125 mm), 1.5 inch (37 mm) and 3 inches (75 mm), and about 2 inches (50 mm), where the term about in this context may refer to +/−0.5 inch (12 mm). 
     In various embodiments, compact centrifugal air blower  304  comprises a permanent magnet motor. For example, with reference to  FIG. 5 , blower  304  may comprise a direct-current brushless motor having a stator  522  surrounded by a magnet  524 . Stator  522  may be physically coupled to a heat diffuser, such as first heat diffuser  526 . In various embodiments, stator  522  is press fit into a cavity  528  of first heat diffuser  526 . 
     Blower  304  may further comprise an impeller  530 . In various embodiments, magnet  524  is physically coupled to impeller  530 , and magnet  524  and impeller  530  concentrically surround stator  522 . For example, magnet  524  may be a cup style magnet integrated into impeller  530 . Impeller  530  and magnet  524  may rotate around stator  522 , pumping air out compact centrifugal air blower  304 . Impeller  530  may comprise, for example, a heat conducting metallic material such as aluminum. In such embodiments, impeller  530  may act to cool magnet  524  during operation of blower  304 . 
     In various embodiments, blower  304  may comprise a second heat diffuser  532  which concentrically surrounds impeller  530 . Second heat diffuser  532  may act to cool stator  522  during operation of blower  304 . In various embodiments, second heat diffuser  532  acts to diffuse the high velocity air leaving impeller  530 , converting it to a lower velocity, higher pressure air. Second heat diffuser  532  may be coupled to stator  522  via, for example, press fitting into cavity  528 . The heat generated in stator  522  may be conducted through cavity  528  and into second heat diffuser  532 . In various embodiments, second heat diffuser  532  may be a vaned centrifugal compressor diffuser. 
     Blower  304  may further comprise an inlet  540  which provides air to blower  304 . In various embodiments, inlet  540  draws air from outside of air cushion  330  in to blower  304 . Inlet  540  may, for example, be oriented perpendicularly to stator  522 . 
     In various embodiments, blower  304  may comprise an outlet  542 . Outlet  542  is in fluid communication with and provide pressurized air to air cushion  330 . Similar to inlet  540 , outlet  542  may be oriented perpendicularly to stator  522 . In various embodiments, inlet  540  comprises a constant velocity configuration that reduces turbulence in the incoming air. Although described in connection with a single blower  304 , system  100  may comprise multiple blowers, and each blower may comprise one associated inlet, though in various embodiments one blower is associated with multiple inlets. In further embodiments, a single inlet may supply air to one or more compact centrifugal air blowers. 
     In various embodiments, impeller  530  forces air across second heat diffuser  532  and out of inlet  540 . Such configurations may provide improved cooling of stator  522  by providing air flow across and through second heat diffuser  532 . 
     Centrifugal air blower  304  is controlled by centrifugal air blower controller  302 . Air cushion cargo shuttle  114  may comprise one or more centrifugal air blower controllers. In various embodiments, each centrifugal air blower has one associated centrifugal air blower controller, though in various embodiments one centrifugal air blower controller controls multiple centrifugal air blowers. Centrifugal air blower controller  302  may provide power and instructions to centrifugal air blower  304  to control how and when centrifugal air blower  304  operates. 
     As shown, air cushion cargo shuttle  114  has four centrifugal air blower controllers  302 ,  414 ,  416 , and  418  driving four centrifugal air blowers  304 ,  420 ,  422 , and  424  to blow air into four different volumes  402 ,  426 ,  428 , and  430 . Each centrifugal air blower controller may further comprise a proximity sensor that may be configured to measure the proximity of a portion of air cushion cargo shuttle  114  to floor panel  112 . For example, proximity sensors  406 ,  408 ,  410  and  412  may be associated with each centrifugal air blower controller  302 ,  414 ,  416 , and  418 . Proximity sensors  406 ,  408 ,  410  and  412  may be used in a closed loop control mechanism to modulate the output of four centrifugal air blowers  304 ,  420 ,  422 , and  424 . In that regard, centrifugal air blower controllers  302 ,  414 ,  416 , and  418  may command four centrifugal air blowers  304 ,  420 ,  422  to blow air into volumes  402 ,  426 ,  428 , and  430  until the proximity sensors  606 ,  608 ,  610  and  612  indicate that a desired proximity has been reached. 
     Moreover, data from proximity sensors  406 ,  408 ,  410  and  412  may be used to detect and compensate for uneven cargo loads. For example, in the event cargo  202  shifts to one portion of air cushion cargo shuttle  114  or otherwise exerts more force on a portion of air cushion cargo shuttle  114  relative to another, data from proximity sensors  406 ,  408 ,  410  and  412  may detect that one portion of air cushion cargo shuttle  114  is not as far from floor panel  112  as one or more other portions of air cushion cargo shuttle  114 . In that regard, where insufficient distance from floor panel  112  is achieved, a centrifugal air blower controller may command its associated centrifugal air blower to increase output to compensate for the uneven load. 
     In that regard, in operation, cargo such as cargo  202  may be loaded onto air cushion cargo shuttle  114  at an aft position, such as a position proximate aft drive shuttle unit  102 . Cargo  202  may be positioned onto air cushion cargo shuttle  114  using power drive unit  308  and roller  306 . During loading of cargo  202 , air cushion cargo shuttle  114  may be in contact with floor panel  112 . Once cargo  202  is suitably positioned on top of air cushion cargo shuttle  114  (where the phrase “on top” in this context may refer to distance across the positive z direction), a control system for centrifugal air blower controller  302  may instruct centrifugal air blower  304  to begin operation. In this manner, air from inlets  540  is pulled into centrifugal air blower  304  and centrifugal air blower  304  blows this air into volume  402 . As more air is blown into volume  402 , the increased air pressure may act to lift air cushion cargo shuttle  114  apart from floor panel  112 . In this context, the phrase “lift apart” may refer to movement of air cushion cargo shuttle  114  in the positive z direction. In various embodiments, the pressure in volume  402  may reach between 1 psi (6.89 kPa) to 10 psi (68.9 kPa), between 2 psi (13.7 kPa) and 6 psi (41.3 kPa), and about 4 psi (27.5 kPa), where the term about in this context may refer to +/−0.5 psi (3.4 kPa). 
     A control system comprising, for example, a processor and a tangible, non-transitory memory may be configured to be in electrical and/or logical communication with centrifugal air blower controller  302 . For example, the control system may communicate with centrifugal air blower controller  302  via one or more shuttle belts. The control system may instruct the centrifugal air blower controller  302  to start, stop, and modulate the output of centrifugal air blower  304 . 
     During operation of centrifugal air blower  304 , cargo  202  may lift apart from floor panel  112 , thus reducing the friction between air cushion cargo shuttle  114  and the floor panel  112 . Stated another way, dry friction may be equal to the coefficient of friction multiplied by the normal force. By eliminating the contact between air cushion cargo shuttle  114  and the floor panel  112 , the two surfaces do not interact to cause friction. In various embodiments, there may be contact between air cushion cargo shuttle  114  and the floor panel  112  during operation of centrifugal air blower  304 , though the air pressure will oppose the normal force (i.e., force in the negative z direction) exerted by cargo  202  and thus friction will be reduced because of this reduction in the normal force. 
     While cargo  202  is lifted apart from floor panel  112 , the forward shuttle drive unit  204  may rotate its bobbin, causing forward drive shuttle belt  208  to pull air cushion cargo shuttle  114  and cargo  202  forward. Aft drive shuttle unit  104  may be allowed to exert a low level drag force on shuttle drive belt  108 , thus allowing aft drive shuttle belt  108  to extend in a forward direction. A low level drag force exerted by aft drive shuttle unit  104  may prevent excessive cargo velocity and may maintain stability in the event an aircraft is not precisely level. Once cargo  202  is positioned in the aircraft at a desired position, the control system may instruct the centrifugal air blower controller  302  to turn off or lower the output of centrifugal air blower  304 . In that regard, due to loss of air pressure in volume  402 , air cushion cargo shuttle  114  may move in a negative z direction and contact floor panel  112 . As air cushion cargo shuttle  114  moves towards floor panel  112 , cargo  202  may come to rest on support rails  222 . Thus, the air cushion cargo shuttle  114  may separate from the cargo  202  as the cargo  202  is restrained from motion in the negative z direction by support rails  222 . In this manner, air cushion cargo shuttle  114  may be brought aft to load additional cargo. The aft drive shuttle unit  102  may rotate its bobbin, causing aft drive shuttle belt  108  to pull air cushion cargo shuttle  114  aft. Additional cargo may now be loaded and the process may proceed again. 
     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. 
     Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment,” “an embodiment,” “an example embodiment,” 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. 
     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.