Patent Publication Number: US-2023150309-A1

Title: Composite pdu tire in an aircraft cargo handling system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to, and the benefit of, India Patent Application No. 202141052826, filed Nov. 17, 2021 (DAS Code E86F) and titled “COMPOSITE PDU TIRE IN AN AIRCRAFT CARGO HANDLING SYSTEM,” which is incorporated by reference herein in its entirety for all purposes. 
     FIELD 
     The present disclosure relates to a tire, and more specifically, to a composite PDU tire configured to resist chipping. 
     BACKGROUND 
     Many aircraft have at least one cargo bay designed to receive cargo. These aircraft cargo bays include utilize powered cargo loading systems comprising a plurality of powered drive units (PDUs) to assist the loading of cargo and equipment into the aircraft. A train and/or series of PDUs may serve to assist pallets and containers of desired dimensions to travel down from fore to aft and from aft to fore of an aircraft (e.g., down the body of the aircraft), typically to the main and lower cargo compartments of the aircraft. Conventionally, PDUs comprise tires to provide motive force and adequate traction to move air freight pallets and containers within the cargo bay, and into and out of the cargo bay. The tires may include thin layers of friction material molded onto a large diameter rigid hub. Typically, PDU tires used in cargo handling systems need to be replaced due to chipping, which render them less effective in providing traction. Additionally, frequent replacements add to maintenance costs. 
     SUMMARY 
     A composite PDU tire for use with a cargo loading system is disclosed herein. In accordance with various embodiments, the tire may comprise a cylindrical region, a first edge region, and a second edge region. The cylindrical region may have a first circumferential groove and a second circumferential groove, and may be located, at least, between the first edge region and the second edge region. 
     In various embodiments, the first edge region may have a fillet and may be coupled to the first circumferential groove at a first bonding region. In various embodiments, the second edge region may have a fillet and may be coupled to the second circumferential groove at a second bonding region. 
     In various embodiments, the first edge region and the second edge region may comprise a first material. In various embodiments, the cylindrical region may comprise a second material. The first material may be stiffer than the second material. In various embodiments, the first material and the second material may be different. 
     In various embodiments, the first edge region may comprise a first extended cylindrical step. The first extended cylindrical step may be coupled to the first circumferential groove of the cylindrical region at the first bonding region. In various embodiments, the second edge region may comprise a second extended cylindrical step. The second extended cylindrical step may be coupled to the second circumferential groove of the cylindrical region at the second bonding region. 
     In various embodiments, the first edge region may comprise a first box joint profile. The first box joint profile may be coupled to a first complementary interlocking profile extending from the first circumferential groove at the first bonding region. In various embodiments, the second edge region may comprise a second box joint profile coupled to a second interlocking profile extending from the second circumferential groove at the second bonding region. 
     In various embodiments, the first edge region may comprise a first dovetail profile. In various embodiments, the first dovetail profile may be coupled to a first dovetail pin extending from the first circumferential groove at the first bonding region. In various embodiments, the second edge region may comprise a second dovetail profile coupled to a second dovetail pin extending from the second circumferential groove at the second bonding region. 
     In various embodiments, the first edge region and the second edge region may have a greater wear resistance relative to the cylindrical region. In various embodiments, the first edge region and the second edge region may have a greater abrasion resistance relative to the cylindrical region. 
     In various embodiments, the cylindrical region may comprise a plurality of treads. In various embodiments, the cylindrical region may have greater traction relative to the edge regions. In various embodiments, the cylindrical region may have a higher coefficient of thermal expansion relative to the edge regions. 
     A tire hub is also disclosed herein. In accordance with various embodiments, the tire hub may comprise a composite tire bonded to the hub. In various embodiments, the composite tire may be molded onto the hub. In various embodiments, the tire hub may comprise an inner rim. The inner rim may define a cavity. In various embodiments, the tire hub may comprise an outer rim. The outer rim may have a flange. In various embodiments, the tire hub may be configured to rotate about an axis. In various embodiments, the tire hub may be configured to rotate about an axle disposed through the inner rim defining a cavity. 
     A method for molding a composite tire over a hub is also disclosed herein. In accordance with various embodiments, the method may comprise disposing a first die relative to a hub. In various embodiments, the method may comprise injecting a first material at a first temperature into the first die. In various embodiments, the first temperature may be above an ambient temperature. In various embodiments, the first material may form a first edge region and a second edge region. 
     In various embodiments, the method may comprise removing the first die from the hub. In various embodiments, the method may comprise disposing a second die relative to the hub. The second die may be disposed while the first material is above the ambient temperature. In various embodiments, the method may comprise injecting a second material into the second die. The second material may be injected into the second die while the first material is above the ambient temperature. In various embodiments, the second material forms a cylindrical region. In various embodiments, the cylindrical region may bond to the first edge region at a first bonding region. In various embodiments, the cylindrical region may bond to the second edge region at a second bonding region. 
     In various embodiments, the first edge region may comprise at least one of an extended cylindrical step, a box joint profile, and a dovetail profile. In various embodiments, the second edge region may comprise at least one of an extended cylindrical step, a box joint profile, and a dovetail profile. 
     The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features and elements as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings. 
    
    
     
       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 an aircraft being loaded with cargo, in accordance with various embodiments; 
         FIG.  2 A  illustrates a surface of an aircraft cargo deck having a PDU base, in accordance with various embodiments; 
         FIG.  2 B  illustrates a PDU, in accordance with various embodiments; 
         FIG.  3    illustrates an offset view of a PDU tire assembly, with a composite tire and hub, in accordance with various embodiments; 
         FIG.  4    illustrates a cross-section of the PDU tire assembly, composite tire, and hub of  FIG.  3   , in accordance with various embodiments; 
         FIG.  5    illustrates a first edge region and a second edge region of the composite tire of  FIG.  3   , in accordance with various embodiments; 
         FIG.  6    illustrates a cylindrical region of the composite tire of  FIG.  3   , in accordance with various embodiments; 
         FIG.  7 A  illustrates a cross-section of an edge region, with a fillet and an extended cylindrical step, in accordance with various embodiments; 
         FIG.  7 B  illustrates a cross-section of an edge region, with a fillet and a box joint profile, in accordance with various embodiments; 
         FIG.  7 C  illustrates a cross-section of an edge region, with a fillet and a dovetail profile, in accordance with various embodiments; 
         FIG.  8    illustrates a cross-section of a first material in a first die, and a hub, in accordance with various embodiments; and 
         FIG.  9    illustrates a cross-section of a second material in a second die, a first material in a first die, and a hub, in accordance with various embodiments. 
         FIG.  10    illustrates a process flow for molding a composite tire. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary 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 changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. The scope of the disclosure is defined by the appended claims. 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. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. 
       FIG.  1    illustrates an aircraft  20  with cargo  22  being loadable through a loading door  24  of the aircraft  20 . Cargo  22  (e.g., a unit load device (ULD), pallet, or the like) may be loaded through loading door  24  and onto a cargo deck  26 .  FIG.  2 A  illustrates cargo deck  26 . Cargo deck  26  includes a cargo deck floor  30 , which may be formed by one or more panels  32  that are coupled to various structural components of aircraft  20  (e.g., to beams, floors, etc.). 
     With continued reference to  FIG.  2 A , in accordance with various embodiments, the cargo deck  26  includes a cargo loading system  60  comprising a plurality of freely rotating conveyance rollers and/or power drive units (PDUs) mounted in the cargo deck  26  to define the conveyance plane. Cargo  22  loaded onto the cargo deck  26  can be moved throughout the cargo deck  26 .  FIG.  2 B  illustrates a PDU  54  with a plurality of tires  56 . The PDU  54  may be configured to engage and propel cargo  22  throughout the cargo deck  26 . The plurality of tires  56  may be configured to engage and provide traction for the movement of any manner of cargo  22 . In this regard, the tires may be employed to rotate to move cargo loaded onto the cargo deck  26 . 
       FIG.  3    illustrates a tire assembly  300 . As shown, the tire assembly  300  may include a composite tire  301  bonded to a hub  308 . In various embodiments, the hub may rotatably couple to a component of the PDU  54 , such as an axle, or any other suitable bar, rod, or central shaft for rotating a wheel or gear. The hub  308  may be configured to rotate in response to a drive motor of the PDU  54 . The hub  308  may also be configured to engage and rotate in response to cargo  22  being rolled across the tire assembly  300 . In various embodiments, the composite tire  301  may include a plurality of regions. For example, the composite tire may include a first edge region  302 , a second edge region  304 , and a cylindrical region  306  located between the first edge region  302  and the second edge region  304 . In accordance with various embodiments, the composite tire  301  may be bonded, for example, to the hub  308 . As described in further detail below, the various regions of the composite tire  301  may be configured to provide adequate traction for the movement of cargo  22 . 
     Referring now to  FIG.  4   , a cross-section view of a tire assembly  400  is illustrated. As shown, for example, the first edge region  402  and the second edge region  404  are coupled to the cylindrical region  406 . Tread  450  may be imprinted or otherwise disposed on the surface of cylindrical region  406 . The edge regions ( 402  and  404 ) may include material that is different from that of the cylindrical region  406 . Stated differently, the edge regions ( 402  and  404 ) may include a first material while the cylindrical region  406  may include a second material. In various embodiments, the first material may be stiffer than the second material. For example, the first material of the first edge region  402  and the second edge region  404  may be configured to have a greater wear resistance and greater abrasion resistance relative to the cylindrical region  406  as cargo  22  is rolled across the tire assembly  300 . Stated differently, the edge regions may be configured to resist chipping as cargo  22  climbs onto the tire. In various embodiments, the first material may be any suitable chip resistant material. Suitable materials include, natural rubber, synthetic rubber, synthetic rubber with high carbon black composition, nitrile butadiene rubber, polyurethane rubber, neoprene, thermoplastic elastomer rubbers, styrene butadiene rubber (SBR), and the like. In various embodiments, the first material may exhibit cutting resistance and tearing resistance properties. In various embodiments, the second material may be any suitable material for providing traction as a ULD rolls across the tire assembly  400 . Suitable materials include, natural rubber, natural rubber with high silica composition, synthetic rubber, synthetic rubber with high carbon black composition, nitrile butadiene rubber, polyurethane rubber, neoprene, thermoplastic elastomer rubbers, styrene butadiene rubber (SBR), and the like. In various embodiments, the second material may exhibit more compliance and offer a higher coefficient of friction than the first material. 
     With continued reference to  FIG.  4   , in accordance with various embodiments, the tire assembly  400  includes a hub  407 . As shown, the hub may include an inner rim  409  defining a cavity  411 , and an outer rim  408 . In various embodiments, the outer rim includes a flange  413 . The hub  407  may be made of any appropriate metal, such as steel, iron, aluminum, or any associated alloys, castings, or forgings. 
     Referring now to  FIG.  5   , additional details of a first edge region  502  and a second edge region  504  are shown. As shown, the first edge region  502  and the second edge region  504  may include fillet profiles ( 514  and  522 ). In various embodiments, the fillet profiles ( 514  and  522 ) may reduce the chances of chipping because of cargo  22  climb. For example, load stress is especially pronounced on the edge regions ( 502  and  504 ) of the composite tire  301  as cargo  22  is loaded onto or across the tire assembly. In having a fillet profile ( 514  and  522 ), the edge regions ( 502  and  504 ) may enable a desirable ramping effect for ULD or cargo  22  climb compared to, for example, a sharper-edged or substantially  90 -degree profile. This effect is desirable since, during cargo loading, cargo  22  may not always be aligned to the tire assembly&#39;s axis to prevent cargo climb across the edges. Stated differently, the edge regions&#39; ( 502  and  504 ) fillet profiles ( 514  and  522 ) may be configured to reduce abrasion and chipping, and diminish stress from cargo  22  impact, extending the life of the composite tire  301 . 
     In continued reference to  FIG.  5   , the first edge region  502  may include a first bonding region  512 . As will be discussed in further detail below, the first edge region  502  may be configured to couple to the cylindrical region  306  of the composite tire  301  at the first bonding region  512 . Likewise, the second edge region  504  may include a second bonding region  516 . In various embodiments, the second edge region  504  may be configured to couple to the cylindrical region  306  of the composite tire  301  at the second bonding region. In various embodiments, the bonding regions ( 512  and  516 ) may be continuous throughout the circumference of the edge regions ( 502  and  504 ) and the cylindrical region  306 . In various embodiments, the bonding regions ( 512  and  516 ) may be of intermittent sections along the circumference of the edge regions ( 502  and  504 ) and the cylindrical region  306 . 
     Referring to  FIG.  6   , additional details of a cylindrical region  606  are shown. As shown, the cylindrical region includes a face  618  that bears the traction load as cargo  22  is loaded onto the tire assembly  300 . The various embodiments, the face  618  of the cylindrical region  606  may include a plurality of treads. The face  618  may include a plurality of treads of any desirable pattern, including for example, directional, symmetrical, asymmetrical, and directional/asymmetrical. 
     In continued reference to  FIG.  6   , the cylindrical region  606  includes a first circumferential groove  616  on one side of the cylindrical region  606 , and a second circumferential groove  614  on another side of the cylindrical region  606 . In various embodiments, the first circumferential groove  616  may be configured to couple to the first edge region  502  at the first bonding region  512 . Likewise, the second circumferential groove  614  may be configured to couple to the second edge region  504  at the second bonding region  516 . 
     In various embodiments, the cylindrical region  606  has greater traction relative to the edge regions ( 302  and  304 ) of the composite tire  301 . In various embodiments, second material of the cylindrical region  606  may have a higher coefficient of thermal expansion relative to the first material of the edge regions ( 302  and  304 ). For example, in response to environmental factors when loading or unloading cargo  22  in various climates, natural thermal expansion and contraction of the cylindrical region  606  and the edge regions ( 302  and  304 ) may occur. It may be desirable, for example, for the second material of the cylindrical region  606  to expand at a higher heating relative to the first material of the edge regions ( 302  and  304 ). This may improve adhesion between the cylindrical region  606  and the edge regions ( 302  and  304 ) as temperature declines. 
     Referring now to  FIG.  7 A , a cross-section of a hub  702  and a cross-section portion  720  of an edge region ( 302  and  304 ) bonded to the hub  702  is shown. As shown, the edge region ( 302  and  304 ) includes a fillet  722  and an extended cylindrical step  724 . In various embodiments, the extended cylindrical step  724  may be set at a substantially 90-degree angle, or at any other suitable angle, relative to the rest of the edge region ( 302  and  304 ). In various embodiments, the extended cylindrical step  724  is configured to increase the bonding area of the edge region ( 302  and  304 ) with the hub  702  for improved adhesion. In various embodiments, the extended cylindrical step  724  is configured to increase the bonding area of the edge region ( 302  and  304 ) with a cylindrical region  306  for improved adhesion at the bonding region  726 . 
       FIGS.  7 B and  7 C  illustrate the cross-section of the hub  702  and edge region ( 302  and  304 ) bonded to the hub of  FIG.  7 A . As shown,  FIG.  7 B  illustrates the edge region ( 302  and  304 ) including a box joint profile  728 . In various embodiments, the box joint profile  728  may couple to a complementary interlocking profile extending from the circumferential groove ( 616  and  614 ) of the cylindrical region  606  at the bonding region  726 .  FIG.  7 C  shows the edge region ( 302  and  304 ) including a dovetail profile  730 . In various embodiments, the dovetail profile  730  may couple to a dovetail pin extending from the circumferential groove ( 616  and  614 ) of the cylindrical region  606  at the bonding region  726 . The edge region ( 302  and  304 ) may include any suitable profile that is configured to increase the bonding area between the edge region ( 302  and  304 ) and the cylindrical region  606  for improved adhesion, and any suitable profile that increases the bonding area between the edge region ( 302  and  304 ) and the hub  702  for improved adhesion. 
     Referring to  FIG.  8   , a cross-section of a tire assembly mold  836  is shown. As shown, and as further referenced in  FIG.  10   , a first die  834  may be disposed (step  80 ) relative to a hub  832 . In various embodiments, the tire assembly mold  836  may include a first end  828  and a second end  830 . In various embodiments, the tire assembly mold  836  may define a recess  838  disposed between the first end  828  and the second end  830 . In various embodiments, using injection molding techniques, a first material may be injected (step  82 ) at a first temperature into the first end  828  and the second end  830  of the first die  834 . The first material may be injected into the first end  828  and the second end  830  simultaneously, or sequentially in any order. In various embodiments, the first temperature may be any suitable temperature above an ambient temperature. In various embodiments, the first material may be any suitable chip resistant material. In various embodiments, injecting the first material into the first die  834  may form (step  84 ) a first edge region  302  and a second edge region  304  of a composite tire  301 . The first edge region  302  and the second edge region  304  formed on the first end  828  and the second end  830 , respectively, may be bonded to the hub  832 . In various embodiments, the first die  834  may be removed (step  86 ) from the hub  832  as the first material is above the ambient temperature. In various embodiments, a suitable adhesive may be applied (step  88 ) to bonding regions ( 512  and  516 ) of the first edge region  302  and the second edge region  304 . Suitable adhesives may include cyanoacrylate adhesives, silicone adhesives, acrylic adhesives, contact adhesives, solvent-based adhesives, epoxies, and the like. 
     In various embodiments, the first edge region  302  and the second edge region  304  may be formed from the first material using any suitable molding technique, such as compression molding, or the like. In various embodiments, using compression molding techniques, the first material may be pressurized, forming a first edge region  302  and a second edge region  304  of a composite tire  301 . In such embodiments, the first die  834  may be removed from the hub  832  as the first material exhibits a higher molding pressure. 
     Referring now to  FIG.  9   , a cross-section of a tire assembly mold  938  is shown. As shown, and as further referenced in  FIG.  10   , a second die  940  may be disposed  90  relative to the hub  932 . In various embodiments, the second die  940  may be disposed  90  relative to the hub  932  while the first material of the first edge region  928  and the second edge region  930  is above the ambient temperature. In various embodiments, the second die  940  may be disposed (step  90 ) between the edge regions ( 928  and  930 ) formed by the first die  834 . In various embodiments, using injection molding techniques, a second material may be injected (step  92 ) into the second die  940  while the first material is above the ambient temperature. In various embodiments, the second material may be injected (step  92 ) at a second temperature above an ambient temperature. In various embodiments, the second temperature may be any suitable temperature above an ambient temperature. In various embodiments, the second material may be any suitable material for providing traction as cargo  22  rolls across a tire assembly  300 . In various embodiments, injecting (step  92 ) the second material into the second die  940  may form (step  94 ) a cylindrical region  306 . In various embodiments, injecting (step  92 ) the second material into the second die  940  to form (step  94 ) the cylindrical region  306  while the first material of the edge regions ( 302  and  304 ) is above an ambient temperature may bond (step  96 ) the cylindrical region  306  to the first edge region  302  and the second edge region  304 . 
     In various embodiments, the cylindrical region  306  may be formed from the second material using any suitable molding technique, such as compression molding, or the like. In various embodiments, using compression molding techniques, the second die  940  may be disposed (step  90 ) relative to the hub  932  while the first material of the first edge region  928  and the second edge region  930  exhibits a higher molding pressure. In such embodiments, the second material may be pressurized, forming a cylindrical region  306  of a composite tire  301 . In various embodiments, pressurizing the second material in the second die  940  to form the cylindrical region  306  while the first material of the edge regions ( 302  and  304 ) exhibits higher molding pressure may bond (step  96 ) the cylindrical region  306  to the first edge region  302  and the second edge region  304 . 
     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. 
     Systems, methods and apparatus are provided herein. In the detailed description herein, references to “various embodiments”, “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 intended to invoke 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.