Patent Publication Number: US-2022234737-A1

Title: Cargo-restraining devices and cargo handling systems including the same

Description:
RELATED APPLICATION 
     The present application is a non-provisional of and claims priority to U.S. Provisional Patent Application No. 63/140,426, filed on Jan. 22, 2021, entitled “CARGO-RESTRAINING DEVICES AND CARGO HANDLING SYSTEMS INCLUDING THE SAME,” the complete disclosure of which is incorporated by reference. 
    
    
     FIELD 
     The present disclosure relates to cargo-restraining devices and cargo handling systems including the same. 
     BACKGROUND 
     Aircraft often include a cargo handling system that is configured to secure cargo or cargo-supporting structures within a stowage region of the aircraft and prevent excessive movement of the cargo during transport. Typically, cargo handling systems also are configured to facilitate loading of the cargo to within the stowage region and unloading of the cargo from within the stowage region. Most cargo handling systems include vertical restraints, which conventionally are flipper-type devices that extend over a peripheral region of cargo-supporting structures to restrict vertical movement thereof. Traditional vertical restraints often are configured to rotate on a vertical axis to allow cargo to pass by during loading and unloading. Some cargo-supporting structures, such as cargo pallets, include protruding structures that directly contact the vertical restraints during loading and unloading and cause the flippers to rotate about the vertical axis. Traditionally, vertical restraints are supplied with a spring that restores the flipper back to the restraint direction after the protruding feature has released the flipper. However, if the protruding feature that engages the vertical restraint is worn, or if the spring over-rotates the flipper after it is released by the protruding structure, the flipper may be ill-positioned and unable to rotate when contacted by a subsequent protruding structure. In some situations, this will cause a jam where the flipper can entirely stop the motion of the cargo-supporting structure and potentially cause damage to the cargo handling system. Thus, a need exists for improved vertical restraints which may prevent or avoid jams with cargo or cargo-supporting structures such as during loading or unloading operations. 
     SUMMARY 
     Cargo-restraining devices and cargo handling systems are disclosed herein. The cargo-restraining devices include a body comprising a protrusion and defining a slot extending at least partially through the body transverse to the protrusion. The slot is configured to slidingly receive an axle of an axle assembly and constrain linear displacement of the body relative to the axle. The axle assembly is configured to operatively couple the cargo-restraining device to a guide rail of a cargo handling system. The cargo-restraining devices also include a torsional biasing mechanism operatively engaged with the body and configured to engage with the axle assembly to bias the body toward a default pivotal position relative to the axle, and a linear biasing mechanism engaged with the body and configured to engage with the axle to bias the body toward a default deflection relative to the axle. The cargo handling systems include a cargo guide assembly comprising a first guide rail and a second guide rail extending at least substantially parallel to one another along a longitudinal axis and laterally spaced apart from one another with a lateral rail spacing extending therebetween. The cargo handling systems also includes a plurality of cargo-restraining devices, which includes a first subset of cargo-restraining devices that are operatively coupled to the first guide rail and a second subset of cargo-restraining devices that are operatively coupled to the second guide rail. In the default pivotal position, the protrusion of each of the first subset and the second subset of the plurality of cargo-restraining devices extends transverse to the longitudinal axis and into the lateral rail spacing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of an aircraft that includes a plurality of cargo-restraining devices according to the present disclosure. 
         FIG. 2  is a schematic representation of cargo-restraining devices according to the present disclosure. 
         FIG. 3  is a schematic representation of the cargo-restraining devices of  FIG. 2  deflected from a default deflection. 
         FIG. 4  is a schematic representation of cargo-restraining devices in various pivotal and linear deflections and of cargo handling systems that include a plurality of cargo-restraining devices according to the present disclosure. 
         FIG. 5  is a top-down view of an example cargo-restraining device, according to the present disclosure. 
         FIG. 6  is a cross-sectional view of the example cargo-restraining device of  FIG. 5 . 
         FIG. 7  is an exploded view of the example cargo-restraining device of  FIG. 5 . 
         FIG. 8  is an isometric view illustrating an example cargo handling system that includes a plurality of the example cargo handling devices of  FIG. 5 . 
     
    
    
     DESCRIPTION 
       FIGS. 1-8  provide examples of cargo-restraining devices  100 , cargo handling systems  300  including cargo-restraining devices  100 , and aircraft  10  including cargo-restraining devices  100  and/or cargo handling systems  300  having cargo-restraining devices  100  according to the present disclosure. Elements that serve a similar or at least substantially similar purpose are labeled with like numbers in each of  FIGS. 1-8 , and these elements may not be discussed in detail here with reference to each of  FIGS. 1-8 . Similarly, all elements may not be labeled in each of  FIGS. 1-8 , but reference numerals associated therewith may be utilized herein for consistency. Elements, components, and/or features that are discussed herein with reference to any of  FIGS. 1-8  may be included in and/or utilized with any of  FIGS. 1-8  without departing from the scope of the present disclosure. 
     Generally, in the figures, elements that are likely to be included in a given example are illustrated in solid lines, while elements that are optional to a given example are illustrated in dashed lines. However, elements that are illustrated in solid lines are not essential to all examples of the present disclosure, and an element shown in solid lines may be omitted from a particular example without departing from the scope of the present disclosure. In the figures, dotted lines may be utilized to indicate structures or elements that are environment to cargo-restraining devices  100  and/or cargo handling systems  300  and/or structures or elements that cargo-restraining devices  100  and/or cargo handling systems  300  are configured to handle. Also in the figures, dot-dash lines may be utilized to indicate various orientations and/or axes. 
       FIG. 1  illustrates examples of aircraft  10  that include and/or cargo handling systems  300  having cargo-restraining devices  100 . Examples of cargo-restraining devices  100  and cargo handling systems  300  are illustrated in  FIGS. 2-7  and discussed in more detail herein with reference thereto. 
     Aircraft  10  may include a fuselage  20  and at least one wing  14  operatively attached to and/or extending from fuselage  20 . Aircraft  10  also may include at least one engine  16  that is operatively attached to fuselage  20 , such as via a corresponding wing  14 . In some examples, aircraft  10  further includes a tail assembly  18  that is operatively attached to and/or at least partially defied by fuselage  20 . In some such examples, tail assembly  18  includes at least one vertical stabilizer  15  and at least one horizontal stabilizer  17 . In some examples, aircraft  10  includes at least one cargo bay, hold, storage region, and/or cargo cabin  12  within fuselage  20  that is configured to receive and/or transport at least one transport structure  320 . As discussed in more detail herein, transport structure  320  includes, supports, or is at least one item of cargo  34 . In some examples, cargo cabin  12  is configured to receive and/or transport a plurality of transport structures  320 . 
     Aircraft  10  further includes a plurality of cargo-restraining devices  100  configured to restrict vertical movement of cargo within aircraft  10 . In some examples, cargo-restraining devices  100  are operably coupled to a cabin floor  24  of cargo cabin  12 . In some examples, aircraft  10  includes at least one cargo handling system  300  that is configured to guide at least one transport structure  320  to a desired position within fuselage  20  while restraining vertical and lateral movement of the at least one transport structure  320 . In some examples, cargo handling system  300  is configured to selectively secure the at least one transport structure  320  in the desired location within fuselage  20 , such as during flight or taxiing. In some examples, cargo handling system  300  is configured to guide a plurality of transport structures  320  to a plurality of desired locations within the fuselage while restraining vertical and lateral movement thereof. In some such examples, cargo handling system  300  is configured to selectively secure the plurality of transport structures  320  in the plurality of desired locations. Cargo handling system  300  may be configured to guide translation of transport structure(s)  320  to within fuselage  20 , such as during loading operations, and/or guide translation of transport structure(s)  320  from within fuselage  20 , such as during unloading operations. 
     Cargo handling system  300  includes at least some of the cargo-restraining devices  100 . In some examples, each cargo handling system  300  is included in or defines a portion of cargo cabin  12 . In particular, cargo cabin  12  may define cabin floor  24 , and cargo handling system  300  may be disposed along and/or define at least a portion of cabin floor  24 . In some examples, aircraft  10  includes a plurality of cargo handling systems  300 . In some such examples, two or more cargo handling systems  300  are included in cargo cabin  12  and/or in a plurality of cargo cabins  12 . Additionally or alternatively, aircraft  10  may include a plurality of cargo handling systems  300  disposed within various other locations of fuselage  20 . Aircraft  10  also may include a plurality of cargo-restraining devices  100  that are separate from any cargo handling system  300 . 
     Aircraft  10  include any suitable type of aircraft, with examples including private aircraft, commercial aircraft, passenger aircraft, military aircraft, jetliners, an autonomous aircraft, wide-body aircraft, and/or narrow body aircraft. While  FIG. 1  illustrates examples in which aircraft  10  is a fixed wing aircraft, cargo-restraining devices  100  and/or cargo handling systems  300  may be included in and/or utilized with any suitable type of aircraft with illustrative non-exclusive examples of other types of aircraft including rotorcraft, helicopters, tiltwing aircraft, tiltrotor aircraft, rockets, rocket propulsion systems, and/or spacecraft. Cargo-restraining devices  100  and/or cargo handling systems  300  also are not limited to aviation and may be included in and/or utilized in various ground transportation vehicles and/or various nautical vehicles. 
       FIG. 2  is a schematic side view representing examples of cargo-restraining devices  100  according to the present disclosure.  FIG. 3  is a side view of the examples of cargo-restraining devices  100  shown in  FIG. 2  deflected from a default deflection  202  shown in  FIG. 2 .  FIG. 4  is a plan view illustrating cargo-restraining devices  100  operably positioned in various deflections and pivotal positions. As shown in  FIGS. 2-4 , cargo-restraining devices  100  include a body  102  comprising a protrusion  104  and defining a slot  106  that extends at least partially through body  102  transverse to protrusion  104 . Slot  106  is configured to slidingly receive an axle  108  of an axle assembly  107  and constrain linear displacement of body  102  relative to axle  108 . Cargo-restraining devices  100  also include a torsional biasing mechanism  120  that is operably engaged with body  102  and configured to engage with axle assembly  107  to bias body  102  towards a default pivotal position  200  relative to axle  108 . Cargo-restraining devices  100  further include a linear biasing mechanism  140  that is engaged with body  102  and configured to engage with axle  108  to bias body  102  towards a default deflection  202  relative to axle  108 . Axle assembly  107  is configured to operatively couple cargo-restraining device  100  to a guide rail  301  of a cargo handling system  300 . As discussed in more detail herein, in some examples, cargo-restraining devices  100  include axle assembly  107  and/or axle  108 . In other examples, axle assembly  107  and/or axle  108  are included in and/or define a portion of an existing cargo handling system  300 , and cargo-restraining devices  100  are configured to receive and operate with an existing axle assembly  107  and/or an existing axle  108 . 
     In some examples, cargo-restraining devices  100  are configured to restrain vertical movement of one or more transport structures  320  positioned within and/or translating through cargo handling system  300 . In such examples, cargo-restraining device  100  may be referred to as a vertical-restraining device  110 . As discussed in more detail herein, cargo handling systems  300  are configured to guide longitudinal translation of one or more transport structures  320  through and/or within a guiding region  328  defined by one or more guide rails  301 . As shown in  FIG. 4 , when cargo-restraining device  100  is operably coupled to guide rail  301 , protrusion  104  of body  102  extends laterally over or within guiding region  328 . In this position, protrusion  104  is configured to selectively engage a portion of transport structure  320  to restrict vertical movement thereof. Cargo-restraining devices  100  also are configured to permit longitudinal translation of transport structure  320  within guiding region  328 . In particular, protrusion  104  may be positioned to slidingly engage transport structure  320  and/or may be positioned to operatively engage transport structure  320  only during vertical movement of transport structure  320 . 
     In some examples, transport structure  320  includes a vertically-protruding feature  324  that is positioned along transport structure  320  such that vertically-protruding feature  324  collides with or contacts protrusion  104  during longitudinal translation of transport structure  320  within guiding region  328 . In view of the above, cargo-restraining devices  100  may be configured to pivot from default pivotal position  200  and/or deflect from default deflection  202  when protrusion  104  is engaged by vertically-protruding feature  324  during longitudinal translation of transport structure  320 . In this way, cargo-restraining device  100  may be described as releasing vertically-protruding feature  324  to permit transport structure  320  to continue to translate along guiding region  328 . 
     In some examples, linear biasing mechanism  140  is configured to permit body  102  of cargo-restraining devices  100  to deflect from default deflection  202 . With reference to  FIG. 2 , slot  106  defines a slot length  214 , and body  102  defines an outermost length  216  that may be at least substantially aligned with slot length  214 . In some examples, slot  106  is dimensioned such that slot length  214  is larger than an axle diameter  164  of axle  108 . In this way, body  102  is configured to slidingly translate along slot  106  relative to axle  108 . As examples, slot length  214  may be selected to be at least 105%, at least 110%, at least 120%, at least 140%, at least 150%, at least 170%, at least 180%, at least 200%, at most 120%, at most 140%, at most 150%, at most 170%, at most 180%, at most 200%, at most 300%, and/or at most 1000% the magnitude of axle diameter  164 . Further shown in  FIG. 2 , slot length  214  extends between a first end region  170  of slot  106  that positioned nearest an outermost extent  218  of protrusion  104  and a second end region  172  of slot  106  that is positioned furthest from outermost extent  218  of protrusion  104 . In some examples, linear biasing mechanism  140  supports body  102  with first end region  170  of slot  106  spaced apart from an exterior surface  166  of axle  108  by a linear separation  220 . As defined herein, linear separation  220  may include the shortest distance between first end region  170  of slot  106  and a point on exterior surface  166  of axle  108 . 
     In some examples, linear biasing mechanism  140  urges axle  108  against second end region  172  of slot  106  to position body  102  in default deflection  202 . In some examples, linear biasing mechanism  140  is configured to permit body  102  to deflect from default deflection  202  to among a plurality of releasing deflections  208 . More specifically, as shown in the sequence between  FIGS. 2-3 , linear biasing mechanism  140  may position body  102  with a maximum linear separation  220  in default deflection  202 . In some examples, linear biasing mechanism  140  permits body  102  to deflect relative to axle  108  towards smaller linear separations  220  such that body  102  is positioned with a smaller linear separation  220  when body  102  is among the plurality of releasing deflections  208 . In this way, outermost extent  218  of protrusion  104  is positioned furthest from axle  108  when body  102  is in default deflection  202  and moves towards axle  108  when body  102  deflects to among the plurality of releasing deflections  208 . In some examples, each releasing deflection  208  corresponds to body  102  being positioned with a corresponding linear separation  220  relative to axle  108 . 
     In some examples, linear biasing mechanism  140  is configured to apply a restoring force between body  102  and axle  108  to bias body  102  towards default deflection  202  and/or to urge body  102  towards default deflection  202  when body  102  is deflected from default deflection  202  and/or is among the plurality of releasing deflections  208 . In some examples, linear biasing mechanism  140  comprises a linear restoring mechanism  142  that is configured to apply the restoring force to urge and/or bias body  102  towards default deflection  202 . In some examples, the restoring force applied by linear restoring mechanism  142  increases with decreasing linear separation  220 . 
     In some examples, linear restoring mechanism  142  is configured to apply an outward restoring force to urge body  102  towards default deflection  202 . In some such examples, linear restoring mechanism  142  is configured to apply the outward restoring force between first end region  170  of slot  106  and axle  108  to resist deflection of first end region  170  of slot  106  towards axle  108  and/or to urge first end region  170  of slot  106  outwardly from axle  108  when body  102  is among releasing deflections  208 . In some such examples, at least a portion of linear restoring mechanism  142  is positioned between first end region  170  of slot  106  and axle  108  when axle  108  is received in slot  106 . In other examples, linear biasing mechanism  140  is configured to apply an inward or contracting restoring force to urge body  102  towards default deflection  202 . In some such examples, linear biasing mechanism  140  is configured to apply the inward or contracting force between second end region  172  of slot  106  and axle  108  when axle  108  is received in slot  106 . In some such examples, at least a portion of linear restoring mechanism  142  is positioned between second end region  172  of slot  106  and axle  108 . 
     Linear restoring mechanism  142  comprises any suitable mechanism, and/or material for applying the restoring force. Examples of suitable linear restoring mechanisms  142  include a spring, a coil spring, a helical spring, a gas spring, a hydraulic spring, a pneumatic spring, a piston, a hydraulic piston, a pneumatic piston, a resilient body, and/or an elastic body. As more specific examples, when linear restoring mechanism  142  is configured to apply an outward restoring force, linear restoring mechanism  142  may include a compression spring and/or an elastically compressible material. When linear restoring mechanism  142  is configured to apply an inward restoring force, linear restoring mechanism  142  may include an extension spring, a tension spring, a tension gas spring, and/or an elastically elongating material. 
     In some examples, linear biasing mechanism  140  is configured to restrict deflection of body  102  beyond a maximum threshold linear deflection. Stated differently, in some examples, linear biasing mechanism  140  is configured to permit linear deflection of body  102  up to the maximum threshold linear deflection. In some examples, the maximum linear deflection is a threshold fraction of slot length  214 , with examples of the threshold fraction including at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at most 90%, at most 80%, at most 70%, at most 60%, at most 50%, at most 40%, at most 30%, at most 20%, at most 10% and/or at most 5%. 
     Linear biasing mechanism  140  is disposed in and/or along any suitable portion or region of cargo-restraining device  100 . In some examples, at least a portion of, or the entirety of, linear biasing mechanism  140  is disposed within slot  106 . In some such examples, linear biasing mechanism  140  extends from or is operably coupled to a sidewall  156  defined by slot  106 . As an example, for some examples in which linear restoring mechanism  142  is configured to apply an outward restoring force, linear restoring mechanism  142  is operably coupled to and/or extends from first end region  170  of slot  106 . Similarly, for some examples in which linear restoring mechanism  142  is configured to apply an inward restoring force, linear biasing mechanism  140  is operably coupled to and/or extends from second end region  172  of slot  106 . 
     Linear biasing mechanism  140  is configured to operatively engage axle  108  in any suitable manner. As shown in  FIG. 2 , in some examples, linear biasing mechanism  140  comprises an axle-contacting member  144  that is configured to operatively engage axle  108  when axle  108  is received in slot  106 . In some examples, axle-contacting member  144  is operatively coupled to linear restoring mechanism  142  to be positioned between linear restoring mechanism  142  and axle  108  when axle  108  is received in slot  106 . In some examples, linear biasing mechanism  140  is configured to pivot with body  102  about axle  108 . In particular, in some examples, axle-contacting member  144  is configured to pivotally or slidingly engage axle  108  to permit and/or guide pivotal movement of body  102  about axle  108 . 
     In some examples, axle-contacting member  144  comprises an axle-contacting region  146  that is dimensioned and shaped to correspond to a region of exterior surface  166  of axle  108 . For example, when axle  108  comprises a cylindrical shape, or exterior surface  166  of axle  108  is cylindrical, axle-contacting region  146  may include a semi-cylindrical recess or channel that is dimensioned and shaped in correspondence with the cylindrical shape of exterior surface  166 . In some such examples, the cylindrical recess or channel defines a bearing surface that is configured to slide circumferentially about exterior surface  166  to permit and/or guide pivotal movement of body  102  about axle  108 . As another example, axle-contacting region  146  may include a ring and/or a rotary bearing that is configured to receive axle  108  and permit and/or guide pivotal movement of body  102  about axle  108 . 
     In some examples, linear restoring mechanism  142  urges axle-contacting member  144  in contact with exterior surface of axle  108  when axle  108  is received in slot  106 . In this way, axle-contacting member  144  may be in contact with axle  108  when body  102  is in default deflection  202  and when body  102  is among the plurality of releasing deflections  208 . Stated differently, in some examples, linear restoring mechanism  142  is configured to permit body  102  to deflect relative to axle-contacting member  144 . 
     In some examples, axle-contacting member  144  is configured to guide linear displacement of body  102  relative to axle  108 . As shown in  FIG. 2 , in some examples, body  102  includes at least one linear guide  148  disposed within slot  106  and extending at least substantially parallel to slot length  214 . Axle-contacting member  144  may include at least one corresponding guide-contacting member  150  that is slidably engaged with linear guide  148 . In such examples, linear guide  148  and guide-contacting member  150  are configured to cooperatively constrain linear displacement of body  102  relative to axle  108 . In some examples, body  102  includes a pair of linear guides  148  disposed along opposing sidewalls  156  of slot  106  and axle-contacting member  144  includes a correspond pair of guide-contacting members  150  that are positioned along axle-contacting member  144  to slidingly engage the pair of linear guides  148 . As a more specific example, linear guide  148  may include a recessed track that extends from first end region  170  of slot  106  along at least a substantial portion of slot length  214  towards second end region  172  of slot  106 , and guide-contacting member  150  may include a correspondingly-shaped protrusion that extends from axle-contacting member  144  to slidingly engage linear guide  148 . 
     In some examples, torsional biasing mechanism  120  is configured to permit body  102  to pivot about axle  108  from default pivotal position  200  to among a plurality of pivotal releasing positions  210 . In such examples, torsional biasing mechanism  120  is configured to permit body  102  to pivot in any suitable pivotal direction such as a clockwise direction, a counterclockwise direction, or in both clockwise and counterclockwise directions. In such examples, torsional biasing mechanism  120  is configured to permit body  102  to pivot through any suitable pivotal angle in the clockwise direction and/or the counterclockwise direction. As discussed herein, the pivotal angle is as defined relative to default pivotal position  200 , in which body  102  is positioned with a pivotal angle of 0 degrees (°). Stated differently, each pivotal releasing position  210  may include body  102  being pivoted to any suitable pivotal angle relative to default pivotal position  200 . Examples of suitable pivotal angles include at least 5°, at least 10°, at least 20°, at least 25°, at least 30°, at least 40°, at least 50°, at least 90°, at most 40°, at most 50°, at most 60°, at most 70°, at most 80°, at most 90°, at most 100°, and/or at most 180°. 
     In some examples, torsional biasing mechanism  120  is configured to apply a torsional restoring force between body  102  and axle assembly  107  to urge body  102  towards default pivotal position  200  when body  102  is pivoted among the plurality of pivotal releasing positions  210 . In some examples, the restoring force applied by torsional biasing mechanism  120  increases with respect to the pivotal angle. In some examples, torsional biasing mechanism  120  also is configured to restrict body  102  from pivoting beyond a threshold maximum pivotal angle relative to default pivotal position  200 , with examples of the threshold maximum pivotal displacement at most 50°, at most 60°, at most 70°, at most 80°, at most 90°, and/or at most 100°. 
     Torsional biasing mechanism  120  is configured to engage with axle assembly  107  in any suitable manner. With reference to  FIGS. 2-3 , in some examples, axle assembly  107  comprises a torsional biasing mechanism-engaging member  158  that torsional biasing mechanism  120  engages when axle  108  is received in slot  106 . In some examples, torsional biasing mechanism-engaging member  158  is configured to restrict torsional biasing mechanism  120  from slidingly or freely pivoting about axle  108 . 
     When included, torsional biasing mechanism-engaging member  158  is disposed along any suitable location of axle assembly  107 . In some examples, torsional biasing mechanism-engaging member  158  is disposed along and/or extends from axle  108 . Additionally or alternatively, in some examples, torsional biasing mechanism-engaging member  158  is disposed along and/or extends from an axle base  174  that is operably coupled to and configured to position axle  108 . Examples of torsional biasing mechanism-engaging members  158  include a ridge and/or a raised rail extending along at least a portion of exterior surface  166  and at least partially aligned with an axle height  162 . Additional or alternative examples of torsional biasing mechanism-engaging members  158  include a protrusion and/or a tab extending from axle base  174 . 
     Torsional biasing mechanism  120  is operably engaged with body  102  in any suitable manner. Torsional biasing mechanism  120  may be operably engaged with body  102  in a manner that permits linear deflection of body  102  relative to axle  108 . In some examples, torsional biasing mechanism  120  is operably engaged with body  102  through linear biasing mechanism  140 . As discussed herein, in some examples, linear biasing mechanism  140  comprises axle-contacting member  144  that is configured to pivotally engage axle  108  and permit linear biasing mechanism  140  and body  102  to pivot about axle  108 . In some such examples, torsional biasing mechanism  120  is engaged with axle-contacting member  144  and is configured to urge body  102  towards default pivotal position  200  by applying a torsional restoring force between axle assembly  107  and axle-contacting member  144 . More specifically, in some examples, axle-contacting member  144  comprises a pivotal engaging member  154  that operatively engages torsional biasing mechanism  120 . In such examples, torsional biasing mechanism  120  urges body  102  towards default pivotal position  200  by engaging pivotal engaging member  154 . Examples of suitable pivotal engaging members  154  include a tab, a protrusion, and/or a toe that extends from axle-contacting region  146  to contact torsional biasing mechanism  120 . 
     As a more specific example, torsional biasing mechanism  120  may include a C-spring that is dimensioned and shaped to extend circumferentially around at least a substantial portion of the circumference of axle  108 . In such examples, torsional biasing mechanism  120  defines a gap  182  between two ends of the C-spring, and gap  182  is configured to receive at least a portion of pivotal engaging member  154  of linear biasing mechanism  140  and at least a portion of torsional biasing mechanism-engaging member  158  of axle assembly  107 . In such examples, pivotal engaging member  154  is configured to apply torque to torsional biasing mechanism  120  when body  102  pivots from default pivotal position  200 , and torsional biasing mechanism-engaging member  158  restricts pivotal movement of torsional biasing mechanism  120  about axle  108 , In this way, torsional biasing mechanism  120  applies a torsional restoring force between torsional biasing mechanism-engaging member  158  and pivotal engaging member  154  responsive to the torque applied by pivotal engaging member  154 . In some such examples, pivotal engaging member  154  and torsional biasing mechanism-engaging member  158  are vertically staggered within gap  182  and/or non-engaging with one another. 
     Torsional biasing mechanism  120  is disposed along and/or within any suitable location of cargo-restraining device  100 . In some examples, torsional biasing mechanism  120  is at least partially or completely disposed within slot  106 . In some examples, torsional biasing mechanism  120  extends around at least a portion of and/or a least a substantial portion of the circumference of axle  108 . Torsional biasing mechanism  120  includes any suitable mechanism, structure, material, and/or combination thereof for biasing body  102  towards default pivotal position  200 . Examples of suitable torsional biasing mechanisms  120  include a torsion spring, a c-spring, a helical torsion spring, a canted coil spring, a torsion bar, and/or a resilient member. In some examples, axle  108  comprises torsional biasing mechanism-engaging member  158  and torsional biasing mechanism  120  is configured to engage with torsional biasing mechanism-engaging member  158  to apply the torsional restoring force. In some examples, torsional biasing mechanism-engaging member  158  extends along at least portion of axle height  162  of axle  108 . 
     As shown in  FIG. 4 , in some examples, cargo-restraining devices  100  are configured to permit body  102  to be deflected from default deflection  202  and simultaneously pivoted from default pivotal position  200 . Stated differently, in some examples, cargo-restraining devices  100  are configured to permit body  102  to be among the plurality of releasing deflections  208  and simultaneously among the plurality of pivotal releasing positions  210 . 
     In some examples, linear biasing mechanism  140  is configured to apply the restoring force between body  102  and axle  108  when body  102  is in default pivotal position  200  and when body  102  is pivoted from the default pivotal position  200  and among the plurality of pivotal releasing positions  210 . In particular, as discussed herein, in some examples, linear biasing mechanism  140  is pivotally engaged with axle  108  and configured to pivot with body  102  about axle  108 , such that linear biasing mechanism  140  may apply the restoring force when body  102  is pivoted to any suitable pivotal angle about axle  108 . 
     Likewise, in some examples, torsional biasing mechanism  120  is configured to apply the torsional restoring force when body  102  is in default deflection  202  and when body  102  is deflected from default deflection  202  and among the plurality of releasing deflections  208 . As discussed herein, in some examples, torsional biasing mechanism  120  operably engages body  102  through axle-contacting member  144  of linear biasing mechanism  140 . In some such examples, axle-contacting member  144  slidingly engages body  102  such that axle-contacting member  144  operably contacts with axle  108  when body  102  is in default deflection  202  and when body  102  is among the plurality of releasing deflections  208 . In this way, torsional biasing mechanism  120  may be operably engaged with body  102  through axle-contacting member  144  when body  102  is in default deflection  202  and among the plurality of releasing deflections  208  such that torsional biasing mechanism  120  may apply the torsional restoring force between body  102  and axle assembly  107  when body  102  is in default deflection  202  and when body  102  is among the plurality of releasing deflections  208 . In view of the above, in some examples, linear biasing mechanism  140  and torsional biasing mechanism  120  are configured to apply the restoring force and the torsional restoring force simultaneously with one another. 
     Body  102  is configured to pivot about a pivotal axis and slot  106  and/or linear biasing mechanism  140 , and may be described as being configured to permit linear deflection of body  102  perpendicular to the pivotal axis. In some examples, the pivotal axis of body  102  is defined by axle  108  and/or extends centrally through axle  108  parallel to axle height  162 . Thus, in some examples, body  102  is configured to pivot about a fixed pivotal axis. In other words, in such examples, body  102  pivots about the same pivotal axis when body  102  is in default deflection  202  and when body  102  is among releasing deflections  208 . 
     In some examples, axle  108  extends from guide rail  301  in an at least substantially vertical direction  226 . Stated differently, in such examples, axle height  162  is at least substantially aligned with vertical direction  226 . In some examples, axle  108  is received in slot  106  such that protrusion  104  extends at least substantially transverse to axle  108  and/or such that slot length  214  extends at least substantially transverse to axle height  162 . In some example, linear biasing mechanism  140  and/or slot  106  engage axle  108  to support body  102  such that protrusion  104  extends at least substantially transverse to axle  108  and/or such that slot length  214  extends at least substantially transverse to axle height  162 . 
     As shown in  FIG. 4 , in some examples, protrusion  104  and/or slot length  214  extends at least substantially in a lateral direction  228  when body  102  is oriented in default pivotal position  200 . In some examples, protrusion  104  and/or slot length  214  extends at least partially in a longitudinal direction  211  and at an angle to lateral direction  228  when body  102  is pivoted among pivotal releasing positions  210 . In other words, in some examples, protrusion  104  and/or slot length  214  extends partially in lateral direction  228  and partially in longitudinal direction  211  when body  102  is among pivotal releasing positions  210 . As defined, longitudinal direction  211  and lateral direction  228  are transverse to one another and vertical direction  226  is transverse to each of longitudinal direction  211  and lateral direction  228 . Thus, for some examples in which linear biasing mechanism  140  is configured to permit body  102  to deflect from default deflection  202  when body  102  is pivoted among pivotal releasing positions  210 , linear biasing mechanism  140  permits body  102  to deflect both in longitudinal direction  211  and in lateral direction  228 . 
     In some examples, axle assembly  107  is included in and/or defines a portion of cargo-restraining device  100 . In such examples, axle  108  is slidingly received in slot  106  such that torsional biasing mechanism  120  and linear biasing mechanism  140  operably engage axle  108 , as discussed herein. In some such examples, axle assembly  107  is configured to operatively couple cargo-restraining device  100  to guide rail  301  of an existing cargo handling system  300 , or of a cargo handling system  300  that is installed in an aircraft  10 . In some examples, axle assembly  107  includes a guide rail coupling mechanism  152  that is configured to couple axle  108  to the guide rail  301  of an existing cargo handling system  300 . In some examples, axle assembly  107  includes an axle base  174  that is configured to orient axle  108  relative to guide rail  301 , and guide rail coupling mechanism  152  is configured to couple axle base  174  to guide rail  301 . In some examples, axle base  174  and guide rail coupling mechanism  152  are configured to orient axle  108  to extend at least substantially in vertical direction  226  from guide rail  301  and/or transverse to a cabin-facing surface  326  of guide rail  301 . In some examples, guide rail coupling mechanism  152  is configured to fixedly position axle  108  relative to guide rail  301 . Guide rail coupling mechanism  152  may include any suitable coupling mechanism such as one or more bolts, one or more screws, one or more nuts, a peg, a ring, a lockbolt, and/or combinations thereof. 
     In other examples, axle assembly  107  is included in and/or defines a portion of an existing or installed cargo handling system  300  and axle  108  may be referred to as an existing axle  108  or an installed axle  108 . In such examples, cargo-restraining device  100  is configured to receive and engage the existing axle  108  such as discussed herein. 
     Slot  106  is configured to receive axle  108  in any suitable manner. In some examples, axle  108  extends through slot  106  transverse to slot length  214  when slot  106  receives axle  108 . In some examples, slot  106  is configured to receive axle  108  such that axle  108  terminates within slot  106 . In other examples, slot  106  is configured to receive axle  108  such that axle  108  extends entirely through slot  106 . In some examples, slot  106  is configured to slidingly engage axle  108  such as to guide pivotal or linear displacement of body  102  about axle  108 . In some examples, second end region  172  of slot  106  is dimensioned and shaped to slidingly contact exterior surface  166  of axle  108 , such that second end region  172  of slot  106  may guide pivotal moment of body  102  when body  102  is in default deflection  202 . Additionally or alternatively, as shown in  FIG. 4 , slot  106  includes a slot width  215 , which is measured perpendicular to slot length  214  and transverse to axle height  162 . Slot width  215  may be dimensioned to closely correspond to axle diameter  164  such that slot  106  slidingly receives axle  108 . In this way, slot  106  may guide deflection of body  102  to and from default deflection  202 . 
     As shown in  FIG. 2 , in some examples, body  102  defines a base surface  111  and an upper surface  116  that is opposed to base surface  111 . In some examples, axle  108  is received in slot  106  such that base surface  111  slidingly contacts axle base  174 . As shown in  FIG. 2 , slot  106  extends through body  102  from base surface  111  towards upper surface  116 . In some examples, slot  106  extends partially through, and terminates within body  102 . In other examples, slot  106  extends entirely through body  102  such that slot  106  forms a channel between upper surface  116  and base surface  111 . 
     As shown in  FIGS. 2 and 3 , in some examples, cargo-restraining devices  100  include an axial retaining mechanism  160  that is configured to retain or bias body  102  to a default vertical position  204  along axle height  162  of axle  108 . In particular, axial retaining mechanism  160  may be configured to restrict body  102  from deflecting up or down along axle height  162  from the default vertical position  204 . When included, axial retaining mechanism  160  also is configured to permit linear and pivotal displacement of body  102  about axle  108 . In some examples, axial retaining mechanism  160  includes a flange  168  that is operably secured on axle  108  to slidingly contact upper surface  116  of body  102 . In such examples, flange  168  restricts vertical movement of body  102  along axle  108  while permitting linear and pivotal displacement of body  102  about axle  108 . Additionally or alternatively, in some examples, axle-contacting member  144  is included in or defines axial-retaining mechanism  160  as discussed in more detail herein. 
       FIG. 4  also illustrates examples of cargo handling systems  300  that include a plurality of cargo-restraining devices  100  according to the present disclosure. As shown, cargo handling systems  300  are configured to guide and restrain at least one transport structure  320 . Cargo handling systems  300  comprise a cargo guide assembly  302  that includes a pair of guide rails  301 . The pair of guide rails  301  includes a first guide rail  304  and a second guide rail  306  that extend at least substantially parallel to one another along a longitudinal axis  212 . First guide rail  304  and second guide rail  306  are laterally spaced apart from one another with a lateral rail spacing  206  extending therebetween. Lateral rail spacing  206  may define the guiding region  328  discussed herein for guiding longitudinal translation of transport structure  320 . As defined herein, longitudinal axis  212  extends parallel to longitudinal direction  211 , perpendicular to lateral direction  228 , and perpendicular the vertical direction  226 . 
     First guide rail  304  and second guide rail  306  are configured to restrict lateral movement of at least one transport structure  320  positioned within lateral rail spacing  206 . In some examples, first guide rail  304  and second guide rail  306  are configured to guide translation of transport structure  320  along the longitudinal axis  212 . Cargo handling systems  300  may be configured to guide, permit, and/or facilitate translation of transport structure  320  in a fore direction  222  along longitudinal axis  212  and/or in an aft direction  224  along longitudinal axis  212 . In some more specific examples, cargo handling systems  300  are configured to guide translation of transport structure  320  in fore direction  222  during loading operations, and guide transport structure  320  in aft direction  224  during unloading operations. 
     In some examples, first guide rail  304  and second guide rail  306  are positioned relative to one another such that lateral rail spacing  206  is dimensioned to correspond to an outermost lateral dimension of transport structure  320 . In this way, first guide rail  304  and second guide rail  306  may restrict lateral movement of transport structure  320  within lateral rail spacing  206  while permitting longitudinal translation of transport structure  320  along longitudinal axis  212 . In some examples, cargo handling systems  300  include a base support structure  330  that defines a base of guiding region  328  and is configured to support the base of a transport structure  320  positioned within and/or translating along guiding region  328 . When cargo handling system  300  is included in aircraft  10 , base support structure  330  may be included in and/or define a portion of cabin floor  24  of aircraft  10 . In some examples, base support structure  330  includes a plurality of rollers  332  positioned within lateral rail spacing  206  and configured to translatably support the base of transport structure  320 . In this way, rollers  332  are configured to facilitate longitudinal translation of transport structure  320  within lateral rail spacing  206 . For examples in which cargo handling systems  300  are included in aircraft  10 , cargo handling systems  300  also are configured to secure transport structure  320  at a desired position within lateral rail spacing  206  to restrict movement of transport structure  320  while aircraft  10  is in flight and/or otherwise moving. In some such examples, cargo handling systems  300  are configured to secure a plurality of transport structures  320  at a plurality of desired locations within lateral rail spacing  206 . 
     Cargo handling systems  300  also include a plurality of cargo-restraining devices  100  operably coupled to the pair of guide rails  301 . More specifically, cargo handling systems  300  include a first subset  308  of cargo-restraining devices  100  that are operably coupled to and extend from first guide rail  304 , and a second subset  310  of cargo-restraining devices  100  that are operably coupled to and extend from second guide rail  306 . Each cargo-restraining device  100  of first subset  308  is operably coupled to first guide rail  304  by axle  108  of a respective axle assembly  107 , and each cargo-restraining device  100  of second subset  310  is operably coupled to second guide rail  306  by axle  108  of a respective axle assembly  107 , as discussed herein. For examples in which cargo handling system  300  is included and/or defines a portion of cabin floor  24 , axle  108  and/or axle assembly  107  may be described as operatively coupling the respective cargo-restraining device  100  to cabin floor  24 . 
     First subset  308  and second subset  310  of cargo-restraining devices  100  may be longitudinally aligned with one another or longitudinally offset from one another. Similarly, first subset  308  and second subset  310  of cargo-restraining devices  100  each include any suitable number of cargo-restraining devices  100 , which may be the same or different from one another. 
     As shown in  FIG. 4 , in default pivotal position  200 , protrusion  104  of each cargo-restraining device  100  of first subset  308  and protrusion  104  of each cargo-restraining device  100  of second subset  310  extends transverse to longitudinal axis  212  and into lateral rail spacing  206 . Cargo-restraining devices  100  are configured to restrict vertical movement of transport structure  320  positioned within lateral rail spacing  206 . More specifically, as illustrated is  FIG. 2 , in some examples, cargo-restraining device  100  is operatively coupled to guide rail  301  such that protrusion  104  extends into lateral rail spacing  206  vertically spaced apart from base support structure  330  of cargo handling system  300 . In some examples, protrusion  104  of each cargo-restraining device  100  defines a vertical retaining surface  112  that is configured to operatively contact transport structure  320  to restrict vertical movement thereof. 
     As shown in  FIG. 4 , in some examples, when transport structure  320  is positioned adjacent a cargo-restraining device  100 , a peripheral region  334  of transport structure  320  extends between vertical retaining surface  112  of protrusion  104  and base support structure  330  of cargo handling system  300 . In such examples, vertical retaining surface  112  is configured to operatively contact peripheral region  334  to restrict vertical movement of transport structure  320  within lateral rail spacing  206 . In some such examples, cargo-restraining device  100  extends from guide rail  301  such that vertical retaining surface  112  slidingly contacts peripheral region  334  to permit longitudinal translation of transport structure  320 . Additionally or alternatively, cargo-restraining device  100  extends from guide rail  301  such that vertical retaining surface  112  only contacts peripheral region  334  when transport structure  320  translates in vertical direction  226 . 
     In some examples, first subset  308  and second subset  310  of cargo-restraining devices  100  are positioned to restrict vertical movement of transport structure  320  simultaneously with one another. In particular, first subset  308  and second subset  310  of cargo-restraining devices  100  may be positioned to operably engage opposing peripheral regions  334  of transport structure  320  to collectively restrict vertical movement thereof. 
     As shown in  FIG. 4 , when cargo-restraining device  100  is not engaged or contacted by a transport structure  320 , linear biasing mechanism  140  orients body  102  in default deflection  202  and torsional biasing mechanism  120  orients body  102  in default pivotal position  200 . In some examples, torsional biasing mechanism  120  is configured to permit pivotal displacement of body  102  from default pivotal position  200  when a torque is applied to protrusion  104  by a transport structure  320  translating along longitudinal axis  212  within lateral rail spacing  206 . 
     As a more specific example, transport structure  320  may include one or more vertically-protruding features  324 . In some examples, vertically-protruding feature  324  is positioned along transport structure  320  such that vertically-protruding feature  324  collides with, engages, and/or contacts protrusion  104  of a cargo-restraining device  100  during longitudinal translation of transport structure  320  within guiding region  328 . In some examples, one or more vertically-protruding features  324  extend along one or more peripheral regions  334  of transport structure  320 . In some examples, torsional biasing mechanism  120  of each cargo-restraining device  100  is configured to permit pivotal displacement of body  102  from default pivotal position  200  to among the plurality of pivotal releasing positions  210  when vertically-protruding feature  324  engages or applies a torque to protrusion  104 . 
     In some examples, protrusion  104  is oriented to release vertically-protruding feature  324  and permit continued translation of transport structure  320  when body  102  is among the plurality of pivotal releasing positions  210 . In other words, torsional biasing mechanism  120  is configured to permit pivotal deflection of protrusion  104  from the path of translation of vertically-protruding feature  324 , thereby allowing vertically-protruding feature  324  to translate past cargo-restraining device  100 . More specifically, body  102  pivot towards aft direction  224  when engaged by a transport structure  320  translating in aft direction  224 , and pivots towards fore direction  222  when engaged by a transport structure  320  translating in fore direction  222 . Once vertically-protruding feature  324  releases protrusion  104  and/or no longer applies torque to protrusion  104 , torsional biasing mechanism  120  applies the torsional restoring force to urge body  102  back to default pivotal position  200 . 
     In some examples, linear biasing mechanism  140  of each cargo-restraining device  100  is configured to permit linear displacement of body  102  from default deflection  202  when transport structure  320  is translating along longitudinal axis  212 , and within lateral rail spacing  206 , and applies a force to body  102  that urges protrusion  104 , or outermost extent  218  thereof, towards axle  108 . In some examples, this force includes a lateral force component, (i.e., force component in lateral direction  228 ) and/or a longitudinal force component (i.e., a force component parallel to longitudinal axis  212 ). More specifically, this force includes both the lateral force component and a longitudinal force component when body  102  is oriented among the pivotal releasing positions  210 . 
     In some examples, linear biasing mechanism  140  is configured to permit linear displacement of body  102  in an outward direction from lateral rail spacing  206 , such that protrusion  104  deflects away from transport structure  320  when body  102  deflects from default deflection  202 . In some examples, linear biasing mechanism  140  is configured to permit linear displacement of body  102  from default deflection  202  to among the plurality of releasing deflections  208  when the force exerted on body  102  exceeds a threshold. In some such examples, linear biasing mechanism  140  is configured to urge body  102  from among the plurality of releasing deflections  208  when the lateral force does not exceed the threshold. In other words, linear biasing mechanism  140  may permit body  102  to deflect from default deflection  202  when body  102  is engaged by transport structure  320  and returns body  102  to default deflection  202  when body  102  is released by, or not engaged by, transport structure  320 . 
     As mentioned, in some examples, linear biasing mechanism  140  is configured to permit body  102  to deflect from default deflection  202  while body  102  is pivoted among pivotal releasing positions  210 . In other words, in some examples, cargo-restraining device  100  is configured to permit body  102  to be simultaneously deflected to among releasing deflections  208  and pivoted to among pivotal releasing positions  210 . As shown in  FIG. 4 , when body  102  is pivoted among pivotal releasing positions  210 , protrusion  104 , or outermost length of body  102 , may extend partially parallel to longitudinal axis  212  and partially in lateral direction  228 . 
     In some examples, linear biasing mechanism  140  is configured to permit body  102  to deflect from default deflection  202  to release body  102  from among the pivotal releasing positions  210 . As shown in  FIG. 4 , in some examples, protrusion  104  is engaged by a transport structure  320  translating within lateral rail spacing  206  while body  102  is pivoted to a pivotal releasing position  210  that orients protrusion  104  to extend towards the oncoming transport structure  320  and/or vertically-protruding feature  324  thereof. In some such examples, linear biasing mechanism  140  is configured to permit body  102  to deflect from default deflection  202  as protrusion  104  is engaged by transport structure  320  in pivotal releasing position  210 . By doing so, linear biasing mechanism  140  permits body  102  to deflect away from lateral rail spacing  206 , and at least partially in a longitudinal direction  211 , as protrusion  104  is engaged by transport structure  320 . More specifically, body  102  is permitted to deflect at least partially in the fore direction  222  for examples in which the transport structure  320  is translating in fore direction  222 , and vice versa for examples in which transport structure  320  is translating in aft direction  224 . In this way, protrusion  104  is moved along and outwardly from the path of translation of transport structure  320 , thereby allowing transport structure  320  to continue to translate longitudinally within lateral rail spacing  206 . In other words, slot  106  and linear biasing mechanism  140  provide cargo-restraining device  100  with an additional degree of freedom that allows protrusion  104  to deflect away from the path of transport structure  320  when protrusion  104  is engaged by transport structure  320  in this pivotal releasing position  210 . 
     More specifically, a cargo-restraining device  100  that does not include the additional degree of freedom provided by slot  106  and linear biasing mechanism  140  may be unable to pivot from this pivotal releasing position  210  when engaged by transport structure  320  as discussed, and thereby unable to move from the path of translation of transport structure  320 . Thus, a cargo-restraining device that does not include the additional degree of freedom provided by slot  106  and linear biasing mechanism  140  may restrict longitudinal translation of, or jam with, transport structure  320  when engaged by transport structure  320  in this pivotal releasing position  210 . In view of this, cargo-restraining device  100  may be described as being configured to prevent jamming with a longitudinally translating transport structure  320 . 
     In some examples, transport structure  320  comprises a plurality of vertically-protruding features  324 , each being positioned to engage a given cargo-restraining device  100  during longitudinal translation of transport structure  320  within lateral rail spacing  206 . In some examples, torsional biasing mechanism  120  is configured return body  102  to default pivotal position  200  after protrusion  104  is engaged and released by a first vertically-protruding feature  324  of a transport structure  320  and before protrusion  104  is engaged by a second vertically-protruding feature  324  such that body  102  is in default pivotal position  200  when the second vertically-protruding feature  234  reaches cargo-restraining device  100 . Likewise, in some examples, linear biasing mechanism  140  is configured to return body  102  to default deflection  202  after protrusion  104  is engaged and released by a first vertically-protruding feature  324  of a transport structure  320  and before protrusion  104  is engaged by a second vertically-protruding feature  324  of the transport structure  320  such that body  102  is in default deflection  202  when the second vertically-protruding feature  324  reaches cargo-restraining device  100 . 
     In some examples, after protrusion  104  is released by the first vertically-protruding feature  324 , torsional biasing mechanism  120  pivots body  102  beyond default pivotal position  200  to a pivotal releasing position  210  that orients protrusion  104  to extend towards the second vertically-protruding feature  324 . In some such examples, protrusion  104  is oriented to extend towards the second vertically-protruding feature  324  when the second vertically-protruding feature  324  engages protrusion  104 . In some such examples, linear biasing mechanism  140  permits body  102  to deflect from default deflection  202  when protrusion  104  is engaged by the second vertically-protruding feature  324  in this orientation, thereby permitting body  102  to move along and outwardly from the path of the second vertically-protruding feature  324 , such as discussed herein. After being released by the second vertically-protruding feature  324 , linear biasing mechanism  140  may return body  102  to default deflection  202  and torsional biasing mechanism  120  may return body  102  to default pivotal position  200 . 
     In some examples, cargo handling systems  300  are configured to guide and restrain a plurality of transport structures  320 , which may be positioned within lateral rail spacing  206  simultaneously with one another. In some such examples, cargo-restraining devices  100  are configured to permit sequential longitudinal translation of a plurality of transport structures  320  within lateral rail spacing  206  while restraining vertical movement thereof. In some examples, each cargo-restraining device  100  is configured to return body  102  to default pivotal position  200  and/or to default deflection  202  after being engaged by a first transport structure  320  and before being engaged by a subsequent transport structure  320 . 
     With continued reference to  FIG. 4 , cargo handling systems  300  may be configured to guide and restrain any suitable type of transport structure  320 . In some examples, transport structure  320  includes, supports, or is at least one item of cargo  34 , and optionally a plurality of items of cargo  34 . As more examples, transport structure  320  may include a container, a shipping container, a cargo pallet, and/or one or more items of cargo supported by the cargo pallet and/or shipping container. For some examples in which transport structure  320  includes a cargo pallet, vertically-protruding feature(s)  324  correspond to pallet blocks disposed on an upper surface of the cargo pallet. For some examples in which cargo handling systems  300  are included in aircraft  10 , transport structure(s)  320  are translated in the fore direction  222  to load transport structure(s) into aircraft  10 , and transport structure(s)  320  are translated in aft direction  224  to unload transport structure(s) from aircraft  10 . 
       FIGS. 5-8  provide an illustrative non-exclusive example of cargo-restraining devices  100  that is indicated at and referred to herein as cargo-restraining device  400 . More specifically,  FIGS. 5-7  illustrate various views of cargo-restraining device  400 , and  FIG. 8  illustrates an example of cargo-restraining device  400  included in an example cargo handling system  300 . Where appropriate, the reference numerals from the schematic illustrations of  FIGS. 2-4  are used to designate corresponding parts of the example cargo-restraining device  400  and the example cargo handling system  300 ; however, the examples of  FIGS. 5-8  are non-exclusive and do not limit cargo-restraining devices  100  or cargo handling systems  300  to the illustrative embodiment of cargo handling system  300  of cargo-restraining device  100 . That is, cargo-restraining devices  100  may incorporate any number of the various aspects, configurations, characteristics, properties, variants, options etc. of cargo-restraining devices  100  that are illustrated and discussed herein with reference to the schematic representations of  FIGS. 2-4  and/or the embodiment of  FIGS. 5-8 , as well as variations thereof, without requiring the inclusion of all such aspects, configurations, characteristics, properties, variants, options etc. Furthermore, any additional aspects, configurations, characteristics, properties, variants, options, etc. disclosed in connection with the example cargo-restraining device  400  of  FIGS. 5-8  may be utilized with and/or otherwise included in other cargo-restraining devices  100 , including cargo-restraining devices  100  according to  FIGS. 2-4 . For the purpose of brevity, each previously discussed component, part, portion, aspect, region, etc. or variants thereof may not be discussed, illustrated, and/or labeled again with respect to the examples of  FIGS. 5-8 ; however, it is within the scope of the present disclosure that the previously discussed features, variants, etc. may be utilized with the examples of  FIGS. 5-8 . 
     With initial reference to  FIG. 5 , illustrate therein is top down view of cargo-restraining device  400 . As shown, axle assembly  107  includes axle  108  and axle base  174  from which axle  108  extends. Axle  108  is operably received in slot  106  of body  102 , with body  102  resting on axle base  174 . In this example, slot  106  extends through the entirety through body  102  from the base surface  111  of body  102  through upper surface  116 . Linear biasing mechanism  140  is positioned within slot  106  and extends between axle  108  and first end region  170  of slot  106 . More specifically, linear biasing mechanism  140  includes axle-contacting member  144  that is slidingly engaged with axle  108  and linear restoring mechanism  142  which extends between axle-contacting member  144  and first end region  170  of slot  106 . In  FIG. 5 , linear restoring mechanism  142  applies an outward restoring force between axle-contacting member  144  and first end region  170  of slot  106  such that body  102  is biased or supported in default deflection  202 . In this example, linear restoring mechanism  142  comprises a compression spring that is configured to supply a restoring force against first end region  170  of slot  106  deflecting towards axle  108 . 
     Axle-contacting region  146  of axle-contacting member  144  comprises a semi-cylindrical recess that is shaped and dimensioned to correspond to the cylindrical exterior surface  166  of axle  108 . Linear restoring mechanism  142  urges axle-contacting region  146  into sliding engagement with axle  108 . In this way, linear biasing mechanism  140  is configured to apply the linear restoring force when body  102  is pivoted to any pivotal position about axle  108 . As shown in dashed lines in  FIG. 5 , in some examples, second end region  172  of slot  106  defines a semi-cylindrical surface that is dimensioned and shaped to correspond to exterior surface  166  of axle  108 . In such examples, second end region  172  of slot  106  is configured to slidingly contact axle  108  when body  102  is in default deflection  202  and guide pivotal displacement of body  102  about axle  108 . 
     With continued reference to  FIG. 5 , the width of body  102  is tapered along protrusion  104  towards the outermost extent  218  of protrusion  104 . In this way, protrusion  104  is provided with two lateral abutting surfaces  114  that are angled or tapered relative to the outermost length of body  102 . In some examples, lateral abutting surfaces  114  are angled to facilitate pivotal deflection of body  102  when protrusion  104  is engaged by a translating transport structure  320 . Protrusion  104  also defines a distal surface  115  that extends between lateral abutting surfaces  114  and includes outermost extent of protrusion  104 . 
     Turning to  FIG. 6 , illustrated therein is a cross-sectional view of cargo-restraining device  400  taken along line  6 - 6  shown in  FIG. 5 . Linear restoring mechanism  142  is removed from slot  106  in  FIG. 6  for sake of clarity. As shown, axle  108  extends from axle base  174  at least substantially perpendicular to a top surface  180  of axle base  174 . Axle  108  defines a cylindrical recess  176  proximate to axle base  174 , such that axle diameter  164  is smaller along cylindrical recess  176  than along the upper portion of axle  108 . In this example, torsional biasing mechanism  120  comprises a C-spring  178  that is received around cylindrical recess  176 . Axle assembly  107  includes torsional biasing mechanism-engaging member  158  that engages with C-spring  178  to prevent C-spring  178  from freely pivoting about axle  108  with body  102 . More specifically, C-spring  178  defines gap  182  that separates the two ends of C-spring  178 , and torsional biasing mechanism-engaging member  158  comprises a tab  184  that protrudes from top surface  180  of axle base  174 . C-spring  178  is received around cylindrical recess  176  such that tab  184  is positioned within gap  182 . In some examples, gap  182  and tab  184  are dimensioned such that tab  184  is closely received in gap  182  and/or contacts the two ends of C-spring  178 . 
     With continued reference to  FIG. 6 , axle-contacting member  144  includes pivotal engaging member  154  that is configured to operatively engage C-spring  178 . Here, pivotal engaging member  154  includes a toe  186  that protrudes from axle-contacting region  146  to extend within cylindrical recess  176 . More specifically, toe  186  extends within gap  182  of C-spring  178  spaced apart from tab  184  of axle assembly  107 . Stated differently, tab  184  of axle assembly  107  is positioned within a lower region of gap  182  and toe  186  of axle-contacting member  144  is positioned within an upper region of gap  182  such that toe  186  is permitted to pivot along with body  102  relative to tab  184 . In some examples, gap  182  and toe  186  are dimensioned such that toe  186  is closely received in gap  182  and/or contacts the two ends of C-spring  178 . 
     In this example, C-spring  178  is configured to engage with toe  186  and tab  184  to bias body  102  to default pivotal position  200  and/or to urge body  102  towards default pivotal position  200  when body  102  is pivoted from default pivotal position  200 . More specifically, C-spring  178  aligns toe  186  with tab  184  when body  102  is in default pivotal position  200 . Toe  186  of axle-contacting member  144  is configured to pivot with body  102  such that toe  186  and tab  184  are pivotally offset from one another when body  102  is pivoted from default pivotal position  200 . Correspondingly, toe  186  and tab  184  engage separate ends of C-spring  178  when body  102  is pivoted from default pivotal position  200 , and thereby apply a compressive force to C-spring  178 . To urge body  102  towards default pivotal position  200 , C-spring  178  applies a restoring force between toe  186  and tab  184  to urge toe  186  and tab  184  into alignment with one another. 
     With continued reference to  FIG. 6 , body  102  includes linear guides  148  that are disposed along lateral sidewalls of slot  106  and extend at least substantially parallel to slot length  214 . Linear guides  148  are configured to slidingly engage with axle-contacting member  144  as discussed herein with reference to  FIG. 7 . 
     Turning to  FIG. 7 , illustrated therein is an exploded view of cargo-restraining device  400 . As shown in this example, C-spring  178  of torsional biasing mechanism  120  is dimensioned and shaped to extend around cylindrical recess  176  of axle  108 , and C-spring  178  defines gap  182  that separates the two ends of C-spring  178 . Toe  186  of axle-contacting member  144  is positioned along axle-contacting region  146  to extend within gap  182  when C-spring  178  is received on axle  108  and axle-contacting member  144  operably engages axle  108 . Axle-contacting member  144  further incudes a pair of guide-contacting members  150  that are dimensioned and shaped to be received in linear guides  148  disposed along the lateral sidewalls of slot  106 . As discussed herein, guide-contacting members  150  and linear guides  148  of body cooperatively are configured to guide lateral translation of body  102  relative to axle  108 . Guide-contacting members  150  and linear guides  148  also may prevent axle-contacting member  144  from translating vertically within slot  106 . In some examples, toe  186  is configured to slidingly engage with an upper ledge  177  defined by cylindrical recess  176  to restrict vertical movement of axle-contacting member  144  along axle  108 . Correspondingly, when guide-contacting members  150  are engaged with linear guides  148 , and toe  186  is slidingly engaged with upper ledge  177 , linear guides  148  and axle-contacting member  144  may restrict vertical movement of body  102  along axle  108  and/or define axial retaining mechanism  160  as discussed herein. 
     Further shown in the example of  FIG. 7 , slot width  215  of slot  106  is dimensioned to closely correspond to axle diameter  164  such that slot  106  is configured to guide linear displacement of body  102  to and from default deflection  202 . Similarly, in some examples, axle-contacting member  144  defines an axle-contacting member width  145  that is at least substantially aligned with slot width  215  when axle-contacting member  144  is received in slot  106 . In some examples, axle-contacting member  144  and slot  106  are dimensioned such that axle-contacting member width  145  closely corresponds to slot width  215  and lateral sidewalls  147  of axle-contacting member  144  slidingly engage lateral sidewalls  156  of slot  106 . In some such examples, axle-contacting member  144  is configured to transmit torsional force from torsional biasing mechanism  120  to body  102  by engaging with lateral sidewalls  156  of slot  106 . 
     Further shown, linear restoring mechanism  142  comprises a compression spring that is configured to extend between first end region  170  of slot  106  and a rear surface of axle-contacting member  144  that is opposed to axle-contacting region  146 . 
       FIG. 8  illustrates an example cargo handling system  300  that includes a plurality of cargo-restraining devices  400 . In this example, cargo handling system  300  is guiding and restraining a transport structure  320  translating in fore direction  222  within lateral rail spacing  206  defined by guide rails  301 . More specifically, transport structure  320  comprises an item of cargo  34  and a cargo pallet  322  that supports the item of cargo  34 . Cargo pallet  322  includes a plurality of pallet blocks  336  that extend upwardly from peripheral region  334  of cargo pallet  322  and define the vertically-protruding features  324  of transport structure  320  discussed herein. Pallet blocks  336  are arranged about the lateral sides of cargo pallet  322  such that protrusion  104  of each cargo-restraining device  400  is engaged by two pallet blocks  336  as cargo pallet  322  translates past each cargo-restraining device  400 . 
     In the example of  FIG. 8 , protrusion  104  of one of the cargo-restraining devices  400  is in operative contact with the second of the two pallet blocks  336 . More specifically, body  102  of this cargo-restraining device  400  is pivoted to a pivotal releasing position  210  that orients the respective protrusion  104  to extend partially in aft direction  224  or opposite the direction which pallet block  336  is translating. In this orientation, pallet block  336  operatively contacts distal surface  115  of protrusion  104 , rather than the lateral abutting surface  114  of protrusion that pallet block  336  would contact when protrusion  104  is engaged by pallet block  336  with body  102  oriented in default pivotal position  200 . 
     In some examples, body  102  is oriented in pivotal releasing position  210  after engaging with the first pallet block  336 . More specifically, in some examples, torsional biasing mechanism  120  over rotates or pivots body  102  beyond default pivotal position  200  after being released by the first pallet block  336 , causing body  102  to be in pivotal releasing position  210  shown in  FIG. 8  when protrusion  104  is engaged by the second pallet block  336 . In this particular example, torsional biasing mechanism  120  pivoted body  102  beyond default pivotal position  200  in a counterclockwise direction. 
     As pallet block  336  translates past cargo-restraining device  400 , pallet block  336  applies force to protrusion  104  that is directed laterally outward from lateral rail spacing  206  and in fore direction  222 . Responsive to this force, linear biasing mechanism  140  permits body  102  to deflect relative to axle  108  along slot  106 , thereby permitting protrusion  104  to deflect in a direction  338  that is laterally outward from lateral rail spacing  206  and in fore direction  222 . Simultaneously, torsional biasing mechanism  120  permits body  102  to pivot in a clockwise direction  340  from the pivotal releasing position  210  shown. In this way, linear biasing mechanism  140 , together with torsional biasing mechanism  120 , permit pivotal and linear deflection of protrusion  104  along with the movement of pallet block  336 , thereby allowing pallet block  336  to continue to translate past the respective cargo-restraining device. Once pallet block  336  releases protrusion  104 , linear biasing mechanism  140  and torsional biasing mechanism  120  return body  102  to default pivotal position  200  and default deflection  202  as illustrated in the adjacent cargo-restraining devices  400 . 
     Illustrative, non-exclusive examples of inventive subject matter according to the present disclosure are described in the following enumerated paragraphs: 
     A1. A cargo-restraining device ( 100 ), comprising: 
     a body ( 102 ) comprising a protrusion ( 104 ) and defining a slot ( 106 ) extending at least partially through the body ( 102 ) transverse to the protrusion ( 104 ), wherein the slot ( 106 ) is configured to slidingly receive an axle ( 108 ) of an axle assembly ( 107 ), wherein the axle assembly ( 107 ) is configured to operatively couple the cargo-restraining device ( 100 ) to a guide rail ( 301 ) of a cargo handling system ( 300 ); 
     a torsional biasing mechanism ( 120 ) operably engaged with the body ( 102 ) and configured to engage with the axle assembly ( 107 ) to bias the body ( 102 ) toward a default pivotal position ( 200 ) relative to the axle ( 108 ); 
     a linear biasing mechanism ( 140 ) engaged with the body ( 102 ) and configured to engage with the axle ( 108 ) to bias the body ( 102 ) toward a default deflection ( 202 ) relative to the axle ( 108 ); and 
     wherein the slot ( 106 ) is configured to constrain linear displacement of the body ( 102 ) relative to the axle ( 108 ). 
     A2. The cargo-restraining device ( 100 ) of paragraph A1, wherein the linear biasing mechanism ( 140 ) is configured to restrict deflection of the body ( 102 ) beyond a maximum threshold linear deflection. 
     A2.1. The cargo-restraining device ( 100 ) of paragraph A2, wherein the slot ( 106 ) has a slot length ( 214 ) traverse to the axle ( 108 ), wherein the body ( 102 ) has an outermost length ( 216 ) that is aligned with the slot length ( 214 ), wherein the maximum threshold linear deflection is a threshold fraction of the slot length ( 214 ), wherein the threshold fraction is at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at most 90%, at most 80%, at most 70%, at most 60%, at most 50%, at most 40%, at most 30%, at most 20%, at most 10% and/or at most 5%. 
     A3. The cargo-restraining device ( 100 ) of any of paragraphs A1-A2.1, wherein the linear biasing mechanism ( 140 ) is configured to apply a restoring force between the body ( 102 ) and the axle ( 108 ) when the body ( 102 ) is displaced from the default deflection ( 202 ) to urge the body ( 102 ) toward the default deflection ( 202 ). 
     A3.1. The cargo-restraining device ( 100 ) of paragraph A3, wherein the linear biasing mechanism ( 140 ) is configured to apply the restoring force between the body ( 102 ) and the axle ( 108 ) when the body ( 102 ) is in the default pivotal position ( 200 ) and when the body ( 102 ) is pivoted from the default pivotal position ( 200 ). 
     A3.2. The cargo-restraining device ( 100 ) of any of paragraphs A3-A3.1, wherein the linear biasing mechanism ( 140 ) comprises a linear restoring mechanism ( 142 ) that is configured to apply the restoring force to bias the body ( 102 ) toward the default deflection ( 202 ) and urge the body ( 102 ) toward the default deflection ( 202 ) when the body ( 102 ) is displaced from the default deflection ( 202 ). 
     A3.2.1. The cargo-restraining device ( 100 ) of paragraph A3.2, wherein the linear restoring mechanism ( 142 ) is configured to apply an outward restoring force between the axle ( 108 ) and a first end region ( 170 ) of slot ( 106 ) to urge the body ( 102 ) toward the default deflection ( 202 ). 
     A3.3. The cargo-restraining device ( 100 ) of any of paragraphs A1-A3.2, wherein at least a portion of the linear biasing mechanism ( 140 ) is disposed within the slot ( 106 ). 
     A4. The cargo-restraining device ( 100 ) of any of paragraphs A1-A3.3, wherein the linear biasing mechanism ( 140 ) comprises an axle-contacting member ( 144 ) configured to pivotally engage the axle ( 108 ) and permit pivotal movement of the linear biasing mechanism ( 140 ) and the body ( 102 ) about the axle ( 108 ). 
     A4.1. The cargo-restraining device ( 100 ) of paragraph A4, when depending from paragraph A3.2, wherein the axle-contacting member ( 144 ) is operatively coupled to the linear restoring mechanism ( 142 ). 
     A4.1.1. The cargo-restraining device ( 100 ) of paragraph A4.1, wherein the linear restoring mechanism ( 142 ) is configured to urge the axle-contacting member ( 144 ) into operative contact with the axle ( 108 ) when the axle ( 108 ) is received in the slot ( 106 ). 
     A4.2. The cargo-restraining device ( 100 ) of any of paragraphs A4-A4.1, wherein the axle-contacting member ( 144 ) is configured to guide pivotal movement of the body ( 102 ) about the axle ( 108 ) when the body ( 102 ) is displaced from the default deflection ( 202 ). 
     A4.3. The cargo-restraining device ( 100 ) of any of paragraphs A4-A4.2, wherein the axle-contacting member ( 144 ) comprises an axle-contacting region ( 146 ) that is dimensioned and shaped to correspond to a region of an exterior surface of the axle ( 108 ). 
     A4.4. The cargo-restraining device ( 100 ) of any of paragraphs A4.1-A4.3, wherein the body ( 102 ) includes at least one linear guide ( 148 ) disposed within the slot ( 106 ) and extending at least substantially parallel to a/the slot length ( 214 ) of the slot ( 106 ), wherein the axle-contacting member ( 144 ) includes at least one guide-contacting member ( 150 ) that is slidably engaged with the at least one linear guide ( 148 ), and wherein the at least one linear guide ( 148 ) and the at least one guide-contacting member ( 150 ) are configured to constrain the linear displacement of the body ( 102 ) relative to the axle ( 108 ). 
     A5. The cargo-restraining device ( 100 ) of any of paragraphs A1-A4.4, wherein the torsional biasing mechanism ( 120 ) is configured to apply a torsional restoring force between the body ( 102 ) and the axle ( 108 ) to urge the body ( 102 ) toward the default pivotal position ( 200 ). 
     A5.1. The cargo-restraining device ( 100 ) of paragraph A5, wherein the torsional biasing mechanism ( 120 ) is configured to apply the torsional restoring force when the body ( 102 ) is in the default deflection ( 202 ) and when the body ( 102 ) is deflected from the default deflection ( 202 ). 
     A5.2. The cargo-restraining device ( 100 ) of any of paragraphs A5-A5.1, when depending from paragraph A3, wherein the torsional biasing mechanism ( 120 ) and the linear biasing mechanism ( 140 ) are configured to apply the torsional restoring force and the restoring force simultaneously with one another. 
     A6. The cargo-restraining device ( 100 ) of any of paragraphs A1-A5.2, wherein at least a portion of the torsional biasing mechanism ( 120 ) is disposed within the slot ( 106 ). 
     A7. The cargo-restraining device ( 100 ) of any of paragraphs A1-A6, further comprising an axial retaining mechanism ( 160 ) configured to retain or bias the body ( 102 ) to a default vertical position ( 204 ) along the axle ( 108 ). 
     A8. The cargo-restraining device ( 100 ) of any of paragraphs A1-A7, wherein the cargo-restraining device ( 100 ) is a vertical-restraining device ( 110 ) configured to restrict vertical movement of a transport structure translating longitudinally relative to the cargo-restraining device ( 100 ). 
     A9. The cargo-restraining device ( 100 ) of any of paragraphs A1-A8, further comprising the axle ( 108 ), wherein the axle ( 108 ) is slidingly received in the slot ( 106 ), wherein the torsional biasing mechanism ( 120 ) is engaged with the axle ( 108 ), and wherein the linear biasing mechanism ( 140 ) is engaged with the axle ( 108 ). 
     A9.1. The cargo-restraining device ( 100 ) of paragraph A9, wherein the axle ( 108 ) is operatively coupled to the guide rail ( 301 ) of the cargo handling system ( 300 ). 
     A9.2. The cargo-restraining device ( 100 ) of any of paragraphs A9-A9.1, wherein the axle assembly ( 107 ) comprises a guide rail coupling mechanism ( 152 ) that is configured to operatively couple the axle ( 108 ) to the guide rail ( 301 ). 
     A9.2.1. The cargo-restraining device ( 100 ) of paragraph A9.2, wherein the guide rail coupling mechanism ( 152 ) is configured to orient the axle ( 108 ) to extend outwardly from and transverse to a cabin-facing surface ( 326 ) of the guide rail ( 301 ). 
     B1. A cargo handling system ( 300 ) configured to guide and restrain at least one transport structure ( 320 ), the cargo handling system ( 300 ) comprising: 
     a cargo guide assembly ( 302 ) comprising a first guide rail ( 304 ) and a second guide rail ( 306 ) extending at least substantially parallel to one another along a longitudinal axis ( 212 ), wherein the first guide rail ( 304 ) and the second guide rail ( 306 ) are laterally spaced apart from one another with a lateral rail spacing ( 206 ) therebetween; 
     a plurality of cargo-restraining devices ( 100 ), wherein each cargo-restraining device ( 100 ) of the plurality of cargo-restraining devices ( 100 ) is the cargo-restraining device ( 100 ) of any of paragraphs A1-A9.2; and 
     wherein a first subset ( 308 ) of the plurality of cargo-restraining devices ( 100 ) are operably coupled to and extend from the first guide rail ( 304 ) and a second subset ( 310 ) of the plurality of cargo-restraining devices ( 100 ) are operably coupled to and extend from the second guide rail ( 306 ). 
     B1.1. The cargo handling system ( 300 ) of paragraph B1, wherein, in the default pivotal position ( 200 ), the protrusion ( 104 ) of each of the first subset ( 308 ) and the second subset ( 310 ) of the plurality of cargo-restraining devices ( 100 ) extends traverse to the longitudinal axis ( 212 ) and into the lateral rail spacing ( 206 ); 
     B1.2. The cargo handling system ( 300 ) of any of paragraphs B1-B1.1, wherein the first guide rail ( 304 ) and the second guide rail ( 306 ) are configured to restrict lateral movement of the at least one transport structure ( 320 ) positioned within the lateral rail spacing ( 206 ), and wherein the plurality of cargo-restraining devices ( 100 ) are configured to restrict vertical movement of the at least one transport structure ( 320 ) positioned within the lateral rail spacing ( 206 ). 
     B2. The cargo handling system ( 300 ) of any of paragraphs B1-B1.2, wherein the plurality of cargo-restraining devices ( 100 ) are configured to restrict vertical movement of the at least one transport structure ( 320 ) when the at least one transport structure ( 320 ) is translating along the longitudinal axis ( 212 ) within the lateral rail spacing ( 206 ) and when the at least one transport structure ( 320 ) is operably secured within the lateral rail spacing ( 206 ). 
     B2.1. The cargo handling system ( 300 ) of paragraph B2, wherein the first guide rail ( 304 ) and the second guide rail ( 306 ) are configured to guide translation of the at least one transport structure ( 320 ) along the longitudinal axis ( 212 ). 
     B2.2. The cargo handling system ( 300 ) of any of paragraphs B1-B2.1, wherein the torsional biasing mechanism ( 120 ) of each cargo-restraining device ( 100 ) of the plurality of cargo-restraining devices ( 100 ) is configured to permit pivotal displacement of the body ( 102 ) from the default pivotal position ( 200 ) when a torque is applied the protrusion ( 104 ) by the at least one transport structure ( 320 ) translating along the longitudinal axis ( 212 ). 
     B3. The cargo handling system ( 300 ) of any of paragraphs B1-B2.2, wherein the linear biasing mechanism ( 140 ) of each cargo-restraining device ( 100 ) of the plurality of cargo-restraining devices ( 100 ) is configured to permit linear displacement of the body ( 102 ) from the default deflection ( 202 ) when a force is applied to the respective protrusion ( 104 ) by the at least one transport structure ( 320 ) translating along the longitudinal axis ( 212 ) that urges the respective protrusion ( 104 ) towards the respective axle ( 108 ). 
     B3.1. The cargo handling system ( 300 ) of paragraph B3, wherein the linear biasing mechanism ( 140 ) of each cargo-restraining device ( 100 ) of the plurality of cargo-restraining devices ( 100 ) is configured to permit linear displacement of the respective body ( 102 ) from the default deflection ( 202 ) to among a plurality of releasing deflections ( 208 ) when the force exerted on the respective body ( 102 ) exceeds a threshold. 
     B3.1.1. The cargo handling system ( 300 ) of paragraph B3.1, wherein the linear biasing mechanism ( 140 ) is configured to urge the body ( 102 ) from among the plurality of releasing deflections ( 208 ) when the force does not exceed the threshold. 
     B4. The cargo handling system ( 300 ) of any of paragraphs B1-B3.1.1, wherein the linear biasing mechanism ( 140 ) is configured to permit linear displacement of the body ( 102 ) in an outward direction from the lateral rail spacing ( 206 ). 
     B5. The cargo handling system ( 300 ) of any of paragraphs B1-B4, wherein the linear biasing mechanism ( 140 ) of each cargo-restraining device ( 100 ) of the plurality of cargo-restraining devices ( 100 ) is configured to permit body ( 102 ) to deflect in a longitudinal direction ( 211 ) and in an outward direction from the lateral rail spacing ( 206 ) when a force is applied to the protrusion ( 104 ) by the at least one transport structure ( 320 ) translating along the longitudinal axis ( 212 ) while body ( 102 ) is pivoted from the default pivotal position ( 200 ). 
     B6. The cargo handling system ( 300 ) of any of paragraphs B1-B5, wherein each cargo-restraining device ( 100 ) of the first subset ( 308 ) of cargo-restraining devices ( 100 ) is coupled to the first guide rail ( 304 ) by a respective axle ( 108 ), and each cargo-restraining device ( 100 ) of the second subset ( 310 ) of cargo-restraining devices ( 100 ) is coupled to the second guide rail ( 306 ) by a respective axle ( 108 ). 
     B7. The cargo handling system ( 300 ) of any of paragraphs B1-B6, wherein the cargo handling system ( 300 ) is configured to guide and restrain a plurality of transport structures ( 320 ). 
     B8. The cargo handling system ( 300 ) of any of paragraphs B1-B7, wherein the plurality of transport structure ( 320 ) includes, supports, or is at least one item of cargo ( 34 ). 
     C1. An aircraft ( 10 ) comprising: 
     a fuselage ( 20 ) including at least one cargo cabin ( 12 ) configured to receive and transport at least one transport structure ( 320 ); and 
     the cargo handling system ( 300 ) of any of paragraphs B1-B8, wherein the cargo handling system ( 300 ) is configured to guide the at least one transport structure ( 320 ) to a desired position within the at least one cargo cabin ( 12 ) and operably restrain vertical and lateral movement of the at least one transport structure ( 320 ) within the at least one cargo cabin ( 12 ). 
     C2. The aircraft ( 10 ) of paragraph C1, wherein the cargo handling system ( 300 ) is configured to guide a plurality of transport structures ( 320 ) to a plurality of desired positions within the at least one cargo cabin ( 12 ) and operably restrain vertical and lateral movement of the plurality of transport structures ( 320 ) within the at least one cargo cabin ( 12 ). 
     D. An aircraft ( 10 ) comprising: 
     a fuselage ( 20 ) including a cargo cabin ( 12 ) configured to receive and transport at least one transport structure ( 320 ); and 
     a cargo handling system ( 300 ) configured to guide the at least one transport structure ( 320 ) to a desired position within the cargo cabin ( 12 ) and operably restrain vertical and lateral movement of the at least one transport structure ( 320 ) within the cargo cabin ( 12 ), wherein the cargo handling system ( 300 ) comprises a plurality of cargo-restraining devices ( 100 ) configured to restrain vertical movement of the at least one transport structure ( 320 ), wherein each cargo-restraining device ( 100 ) comprises:
         a body ( 102 ) comprising a protrusion ( 104 ) and a defining a slot ( 106 ) extending at least partially through the body ( 102 ) transverse to the protrusion ( 104 );   an axle ( 108 ) slidingly received in the slot ( 106 ) and operatively coupled to a cabin floor ( 24 ) of the cargo cabin ( 12 );   a torsional biasing mechanism ( 120 ) engaged with the axle ( 108 ) and the body ( 102 ) and configured to bias the body ( 102 ) toward a default pivotal position ( 200 ) relative to the axle ( 108 );   a linear biasing mechanism ( 140 ) engaged with the axle ( 108 ) and the body ( 102 ) and configured to bias the body ( 102 ) toward a default deflection ( 202 ) relative to the axle ( 108 ); and   wherein the slot ( 106 ) is configured to constrain linear displacement of the body ( 102 ) relative to the axle ( 108 ).       

     D2. The aircraft ( 10 ) of paragraph D1, wherein the cargo handling system ( 300 ) is configured to guide a plurality of transport structures ( 320 ) to a plurality of desired positions within the cargo cabin ( 12 ) and operably restrain vertical and lateral movement of the plurality of transport structures ( 320 ) within the cargo cabin ( 12 ). 
     E. The use of the cargo handling system ( 300 ) of any of paragraphs B1-B8 to guide at least one transport structure ( 320 ) to within a cargo cabin ( 12 ) of an aircraft ( 10 ) and operably restrain vertical and lateral movement of the at least one transport structure ( 320 ) within the cargo cabin ( 12 ). 
     As used herein, the terms “adapted” and “configured” mean that the element, component, or other subject matter is designed and/or intended to perform a given function. Thus, the use of the terms “adapted” and “configured” should not be construed to mean that a given element, component, or other subject matter is simply “capable of” performing a given function but that the element, component, and/or other subject matter is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the function. It is also within the scope of the present disclosure that elements, components, and/or other recited subject matter that is recited as being adapted to perform a particular function may additionally or alternatively be described as being configured to perform that function, and vice versa. Similarly, subject matter that is recited as being configured to perform a particular function may additionally or alternatively be described as being operative to perform that function. 
     As used herein, the terms “selective” and “selectively,” when modifying an action, movement, configuration, or other activity of one or more components or characteristics of an apparatus, mean that the specific action, movement, configuration, or other activity is a direct or indirect result of one or more dynamic processes, as described herein. The terms “selective” and “selectively” thus may characterize an activity that is a direct or indirect result of user manipulation of an aspect of, or one or more components of, the apparatus, or may characterize a process that occurs automatically, such as via the mechanisms disclosed herein. 
     As used herein, the term “and/or” placed between a first entity and a second entity means one of (1) the first entity, (2) the second entity, and (3) the first entity and the second entity. Multiple entries listed with “and/or” should be construed in the same manner, i.e., “one or more” of the entities so conjoined. Other entities optionally may be present other than the entities specifically identified by the “and/or” clause, whether related or unrelated to those entities specifically identified. Thus, as a non-limiting example, a reference to “A and/or B,” when used in conjunction with open-ended language such as “comprising,” may refer, in one example, to A only (optionally including entities other than B); in another example, to B only (optionally including entities other than A); in yet another example, to both A and B (optionally including other entities). These entities may refer to elements, actions, structures, steps, operations, values, and the like. 
     As used herein, the phrase “at least one,” in reference to a list of one or more entities should be understood to mean at least one entity selected from any one or more of the entities in the list of entities, but not necessarily including at least one of each and every entity specifically listed within the list of entities and not excluding any combinations of entities in the list of entities. This definition also allows that entities may optionally be present other than the entities specifically identified within the list of entities to which the phrase “at least one” refers, whether related or unrelated to those entities specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) may refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including entities other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including entities other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other entities). In other words, the phrases “at least one,” “one or more,” and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B, and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C,” and “A, B, and/or C” may mean A alone, B alone, C alone, A and B together, A and C together, B and C together, A, B, and C together, and optionally any of the above in combination with at least one other entity. 
     As used herein, “at least substantially,” when modifying a degree or relationship, includes not only the recited “substantial” degree or relationship, but also the full extent of the recited degree or relationship. A substantial amount of a recited degree or relationship may include at least 75% of the recited degree or relationship. For example, an object that is at least substantially formed from a material includes an object for which at least 75% of the object is formed from the material and also includes an object that is completely formed from the material. As another example, a first direction that is at least substantially parallel to a second direction includes a first direction that forms an angle with respect to the second direction that is at most 22.5 degrees and also includes a first direction that is exactly parallel to the second direction. As another example, a first length that is substantially equal to a second length includes a first length that is at least 75% of the second length, a first length that is equal to the second length, and a first length that exceeds the second length such that the second length is at least 75% of the first length. 
     The various disclosed elements of apparatuses and steps of methods disclosed herein are not required to all apparatuses and methods according to the present disclosure, and the present disclosure includes all novel and non-obvious combinations and subcombinations of the various elements and steps disclosed herein. Moreover, one or more of the various elements and steps disclosed herein may define independent inventive subject matter that is separate and apart from the whole of a disclosed apparatus or method. Accordingly, such inventive subject matter is not required to be associated with the specific apparatuses and methods that are expressly disclosed herein, and such inventive subject matter may find utility in apparatuses and/or methods that are not expressly disclosed herein.