Patent Publication Number: US-2023150671-A1

Title: Toggle lock restraint for aircraft cargo handling systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to, and the benefit of, India Patent Application No. 202141053044, filed Nov. 18, 2021 (DAS Code B3C2) and titled “TOGGLE LOCK RESTRAINT FOR AIRCRAFT CARGO HANDLING SYSTEMS,” which is incorporated by reference herein in its entirety for all purposes. 
     FIELD 
     The present disclosure generally relates to the field of securing cargo and, more particularly, to engaging cargo that has a distorted edge or base. 
     BACKGROUND 
     Latches or cargo restraints are part of cargo handling systems and are used to restrain Unit Load Devices (ULDs), pallets, and the like in aircraft cargo compartments. ULDs may become warped or bent over time because of overuse. This may prevent cargo restraints from being able to engage an end or base of a ULD edge to secure the same in at least one of the vertical or z dimension. In such cases, the ULD may need to be bent down with large manual force to the pawl level of the cargo restraint and the pawl may then need to be forcefully urged in order to properly engage with the ULD. Cargo compartment operators may need to strike the cargo restraint many times to make it engage with a warped ULD base, which increases cargo loading time and thus, a longer turnaround time for the next flight. At least 2 people may be required in order to engage a cargo restraint with one side of a ULD, which also increases labor costs. 
     SUMMARY 
     A cargo restraint is presented herein. Both the configuration of such a cargo restraint and the operational characteristics/operation of such a cargo restraint are within the scope of this Summary. 
     A cargo restraint includes at least one sidewall having a slot. A first location of the slot is disposed at a first elevation, while a second location of the slot is disposed at a second elevation that is less than the first elevation. The first location and the second location are spaced along a length of the slot, as well as along a longitudinal dimension of the cargo restraint. The cargo restraint further includes a first pivot that is disposed at a fixed location on the first pawl. The first pivot is positioned within and movable along the length of the slot and including in the longitudinal dimension of the restraint. Movement of the first pivot along the length of the slot may be used to change the elevation of a restraining head of the first pawl, for instance to position the restraining head to engage a retention rim of a ULD that is spaced above a conveyor plane (e.g., by moving the first pivot from a home location to the first location, which may increase the elevation of the restraining head), to dispose the restraining head in engagement with such a retention rim to move the same at least in the direction of the conveyor plane (e.g., by moving the first pivot from the first location to the second location, which may decrease the elevation of the restraining head), or both. 
     Various aspects of the present disclosure are also addressed by the following examples and in the noted combinations: 
     1. A cargo restraint comprising: 
     a first wall comprising a first slot, wherein a first location of said first slot is disposed at a first elevation, wherein a second location of said first slot is disposed at a second elevation that is less than said first elevation, and wherein said first location and said second location are spaced along a length of said slot and along a longitudinal dimension of said cargo restraint; 
     a first pawl; and 
     a first pivot disposed at a fixed location on said first pawl and movable along said length of said first slot, wherein said first pawl is pivotable relative to said first wall about said first pivot. 
     2. The cargo restraint of example 1, wherein said second location is closer to cargo when engaged by said first pawl than said first location. 
     3. The cargo restraint of any of examples 1-2, wherein said first slot comprises a first slot end and a second slot end, wherein said first location is between said first slot end and said second slot end along said length of said first slot, and wherein said second location is at said second slot end. 
     4. The cargo restraint of any of examples 1-2, wherein said first slot comprises a first slot end and a slot second end, wherein said first slot comprises a first lower sidewall and a first upper sidewall that are spaced in a width dimension of said first slot and that each extend along said length of said first slot from said first slot end to said second slot end. 
     5. The cargo restraint of example 4, wherein an elevation of said first lower sidewall increases proceeding along said length of said first slot from said first slot end to said first location. 
     6. The cargo restraint of any of examples 4-5, wherein said elevation of said first lower sidewall decreases proceeding along said length of said first slot from said first location in a direction of said second location. 
     7. The cargo restraint of any of examples 4-6, wherein an elevation of a first part of said first upper sidewall decreases proceeding along said length of said first slot in a direction of said second location. 
     8. The cargo restraint of any of examples 4-7, said second slot end comprises said second location and is semicircular, wherein said first upper sidewall initially extends downwardly proceeding from said second slot end and then at least generally upwardly to define a stopper that projects into an interior of said first slot. 
     9. The cargo restraint of any of examples 1-8, wherein said first location corresponds with an unlatched configuration for said first pawl and said second location corresponds with a latched configuration for said first pawl. 
     10. The cargo restraint of any of examples 1-9, further comprising: a second pawl pivotally connected to said first wall at a second fixed location. 
     11. The cargo restraint of example 10, further comprising: 
     a first spring interconnecting between said first pawl and said second pawl so that advancing said first pivot along said length of said first slot proceeding from said first location in a direction of said second location changes said second pawl from a first position to a second position that is more erect than said first position. 
     12. The cargo restraint of any of examples 10-11, wherein said second fixed location is located between said first location and said second location in said longitudinal dimension of said cargo restraint. 
     13. The cargo restraint of any of examples 1-12, wherein said first pawl is pivotable relative to said first wall about a single axis. 
     14. The cargo restraint of example 13, wherein a position of said single axis is variable along said length of said first slot. 
     15. The cargo restraint of any of examples 1-14, further comprising: 
     a second wall laterally spaced from said first wall and comprising a second slot, wherein said first slot and said second slot are of a common configuration; and 
     a second pivot disposed at a fixed location on said first pawl and movable along a length of said second slot, wherein said first pawl is pivotable relative to said second wall about said second pivot. 
     16. A cargo system comprising a first structure and the cargo restraint of any of examples 1-15, wherein said first structure comprises a first surface and said first pawl comprises a restraining head engageable with said first surface. 
     17. The cargo system of example 16, further comprising: a first configuration comprising said first pawl being erect, said first pivot being at said first location, and said restraining head being at a higher elevation than said first surface. 
     18. The cargo system of example 17, further comprising: an intermediate configuration spaced from said first location in a direction of said second location within said longitudinal dimension, wherein said intermediate configuration comprises said restraining head being in overlying and spaced relation to said first surface. 
     19. The cargo system of any of examples 17-18, further comprising: a second configuration comprising said first pawl being erect, said first pivot being at said second location, and said restraining head engaging said first surface. 
     20. The cargo system of any of examples 17-19, wherein said first surface curves upwardly proceeding in direction of said cargo restraint. 
     21. The cargo system of any of examples 17-20, wherein said first structure is a ULD. 
     22. An aircraft comprising the cargo system of any of examples 16-21. 
     23. A method of restraining a first structure with a cargo restraint comprising a first slot and a first pawl, wherein said first pawl comprises a first pivot disposed at a fixed location on said first pawl and disposed within said first slot, said method comprising: 
     moving said first pivot at a first time along said first slot to a first location; 
     increasing an elevation of said first pivot in response to said moving said first pivot at a first time; 
     disposing said first pawl in an erect position, wherein said first pawl being in said erect position with said first pivot being at said first location disposes a restraining head of said first pawl at a higher elevation than a first surface of said first structure; 
     moving said first pivot at a second time along said first slot from said first location to a second location and with said first pawl being in said erect position, said first time being different from said second time; 
     decreasing said elevation of said restraining head in response to said moving said first pivot at a second time; and 
     engaging said restraining head against said first surface of said first structure using said decreasing. 
     24. The method of example 23, further comprising: 
     changing said first pawl from a first orientation to a second orientation prior to said moving said first pivot at a first time, wherein said second orientation comprises said first pawl being more erect than said first orientation. 
     25. The method of example 24, wherein said first orientation comprises said first pawl being at least generally horizontally disposed. 
     26. The method of any of examples 24-25, wherein said disposing comprises said changing and wherein said disposing is executed before said moving said first pivot at a first time. 
     27. The method of any of examples 24-26, wherein said changing is manually executed by an operator. 
     28. The method of any of examples 23-27, further comprising: providing a single pivot axis for said first pawl, wherein said first pivot comprises said single pivot axis, and wherein each of said moving said first pivot at a first time and said moving said first pivot at a second time comprise changing a location of said single pivot axis along said first slot. 
     29. The method of any of examples 23-28, wherein said cargo restraint further comprises a second pawl, said method further comprising: 
     changing said second pawl from a third orientation to a fourth orientation, wherein said fourth orientation comprises said second pawl being more erect than said third orientation. 
     30. The method of example 29, wherein said third orientation comprises said first pawl being at least generally horizontally disposed. 
     31. The method of any of examples 29-30, wherein said changing said second pawl is in response to said moving said first pivot at a second time. 
     32. The method of any of examples 29-31, further comprising: biasing said second pawl to said third orientation. 
     33. The method of any of examples 23-28, wherein said cargo restraint further comprises a second pawl, wherein said moving said first pivot at a second time comprises lifting said second pawl into a latching configuration. 
     34. The cargo system of any of examples 23-33, wherein said first structure is a ULD. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. An understanding of the present disclosure may be further facilitated by referring to the following detailed description and claims in connection with the following drawings. While the drawings illustrate various embodiments employing the principles described herein, the drawings do not limit the scope of the claims. Reference to “in accordance with various embodiments” in this Brief Description of the Drawings also applies to the corresponding discussion in the Detailed Description. 
         FIG.  1 A  illustrates a schematic of an aircraft being loaded with cargo, in accordance with various embodiments; 
         FIG.  1 B  illustrates a portion of a cargo handling system, in accordance with various embodiments; 
         FIG.  2    illustrates a portion of a cargo handling system, in accordance with various embodiments; 
         FIG.  3    illustrates a schematic view of a cargo deck having a cargo handling system with a plurality of PDUs, in accordance with various embodiments; 
         FIG.  4 A  is a perspective view of a cargo restraint having outer and inner pawls in an erected position, in accordance with various embodiments; 
         FIG.  4 B  is another perspective view of the cargo restraint in the  FIG.  4 A  configuration, in accordance with various embodiments; 
         FIG.  4 C  is an exploded, perspective view of the cargo restraint of  FIG.  4 A , in accordance with various embodiments; 
         FIG.  4 D  is a perspective view of the cargo restraint of  FIG.  4 A  that illustrates a spring between the outer and inner pawls, in accordance with various embodiments; 
         FIG.  5 A  is an enlarged view of a slot used to control the elevation of the outer pawl of the cargo restraint of  FIGS.  4 A- 4 D , in accordance with various embodiments; 
         FIG.  5 B  is a side view of the slot shown in  FIG.  5 A  that illustrates representative positions of a pivot pin of the outer pawl in the slot, in accordance with various embodiments; 
         FIG.  6 A  is a cutaway, side view of the cargo restraint of  FIGS.  4 A- 4 D  with the outer and inner pawls each being in a retracted position, in accordance with various embodiments; 
         FIG.  6 B  is an enlarged side view that shows the position of one outer pawl pivot in the slot for the  FIG.  6 A  configuration, in accordance with various embodiments; 
         FIG.  7 A  is a cutaway, side view of the cargo restraint of  FIGS.  4 A- 4 D  with the outer pawl being moved from a retracted position to an erected position, in accordance with various embodiments; 
         FIG.  7 B  is an enlarged side view that shows the position of one outer pawl pivot in the slot for the  FIG.  7 A  configuration, in accordance with various embodiments; 
         FIG.  8 A  is a cutaway, side view of the cargo restraint of  FIGS.  4 A- 4 D  with the outer pawl being in an erected position and with the outer pawl having been moved to its maximum elevated position to accommodate engagement of a retention base of a ULD that is disposed above a conveyor plane, in accordance with various embodiments; 
         FIG.  8 B  is an enlarged side view that shows the position of one outer pawl pivot in the slot for the  FIG.  8 A  configuration, in accordance with various embodiments; 
         FIG.  9 A  is a cutaway, side view of the cargo restraint of  FIGS.  4 A- 4 D  with the outer pawl being in an erected position, with the restraining head of the outer pawl having engaged the retention base of the ULD and having moved the retention base toward a conveyor plane, and with the inner pawl being moved toward its erected position, in accordance with various embodiments; 
         FIG.  9 B  is an enlarged side view that shows two representative positions of one outer pawl pivot in the slot for the  FIG.  9 A  configuration, in accordance with various embodiments. 
         FIG.  10 A  is a cutaway, side view of the cargo restraint of  FIGS.  4 A- 4 D  with the outer pawl and inner pawl each being in an erected position and with the restraining head of the outer pawl having moved the retention base of the ULD to the conveyor plane, in accordance with various embodiments; 
         FIG.  10 B  is an enlarged side view that shows the position of one outer pawl pivot pin in the slot for the  FIG.  10 A  configuration, in accordance with various embodiments; and 
         FIG.  11    is a method for restraining a structure with a cargo constraint, in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIG.  1 A , a schematic view of an aircraft  10  having a cargo deck  12  located within a cargo compartment  14  is illustrated, in accordance with various embodiments. The aircraft  10  may comprise a cargo load door  16  located, for example, at one side of a fuselage structure of the aircraft  10 . A unit load device (ULD)  20  may be loaded through the cargo load door  16  and onto the cargo deck  12  of the aircraft  10  or, conversely, unloaded from the cargo deck  12  of the aircraft  10 . In general, ULDs are available in various sizes and capacities, and are typically standardized in dimension and shape. Once loaded with items destined for shipment, the ULD  20  is transferred to the aircraft  10  and then loaded onto the aircraft  10  through the cargo load door  16  using a conveyor ramp, scissor lift or the like. Once inside the aircraft  10 , the ULD  20  is moved within the cargo compartment  14  to a final stowed position. Multiple ULDs may be brought on-board the aircraft  10 , with each ULD  20  being placed in a respective stowed position on the cargo deck  12 . After the aircraft  10  has reached its destination, each ULD  20  is unloaded from the aircraft  10  in similar fashion, but in reverse sequence to the loading procedure. To facilitate movement of the ULD  20  along the cargo deck  12 , the aircraft  10  may include a cargo handling system as described herein in accordance with various embodiments. 
     Referring now to  FIG.  1 B , a portion of a cargo handling system  100  is illustrated, in accordance with various embodiments. The cargo handling system  100  is illustrated with reference to an XYZ coordinate system, with the X-direction extending longitudinally and the Z-direction extending vertically with respect to an aircraft in which the cargo handling system  100  is positioned, such as, for example, the aircraft  10  described above with reference to  FIG.  1 A . In various embodiments, the cargo handling system  100  may define a conveyance surface  102  having a plurality of trays  104  supported by a cargo deck  112 , such as, for example, the cargo deck  12  described above with reference to  FIG.  1 A . The plurality of trays  104  may be configured to support a unit load device (ULD)  120  (or a plurality of ULDs), such as, for example, the unit load device (ULD)  20  described above with reference to  FIG.  1 A . In various embodiments, the ULD  120  may comprise a container or a pallet configured to hold cargo as described above. In various embodiments, the plurality of trays  104  is disposed throughout the cargo deck  112  and may support a plurality of conveyance rollers  106 , where one or more or all of the plurality of conveyance rollers  106  is a passive roller. 
     In various embodiments, the plurality of trays  104  may further support a plurality of power drive units (PDUs)  110 , each of which may include one or more drive wheels or rollers  108  that may be actively powered by a motor. In various embodiments, one or more of the plurality of trays  104  is positioned longitudinally along the cargo deck  112 —e.g., along the X-direction extending from the forward end to the aft end of the aircraft. In various embodiments, the plurality of conveyance rollers  106  and the one or more drive rollers  108  may be configured to facilitate transport of the ULD  120  in the forward and the aft directions along the conveyance surface  102 . During loading and unloading, the ULD  120  may variously contact the one or more drive rollers  108  to provide a motive force for transporting the ULD  120  along the conveyance surface  102 . Each of the plurality of PDUs  110  may include an actuator, such as, for example, an electrically operated motor, configured to drive the one or more drive rollers  108  corresponding with each such PDU  110 . In various embodiments, the one or more drive rollers  108  may be raised from a lowered position beneath the conveyance surface  102  to an elevated position protruding above the conveyance surface  102  by the corresponding PDU. As used with respect to cargo handling system  100 , the term “beneath” may refer to the negative Z-direction, and the term “above” may refer to the positive Z-direction with respect to the conveyance surface  102 . In the elevated position, the one or more drive rollers  108  variously contact and drive the ULD  120  that otherwise rides on the plurality of conveyance rollers  106 . Other types of PDUs, which can also be used in various embodiments of the present disclosure, may include a drive roller that is held or biased in a position above the conveyance surface by a spring. PDUs as disclosed herein may be any type of electrically powered rollers that may be selectively energized to propel or drive the ULD  120  in a desired direction over the cargo deck  112  of the aircraft. The plurality of trays  104  may further support a plurality of restraint devices  114 . In various embodiments, each of the plurality of restraint devices  114  may be configured to rotate downward as the ULD  120  passes over and along the conveyance surface  102 . Once the ULD  120  passes over any such one of the plurality of restraint devices  114 , such restraint device  114  returns to its upright position, either by a motor driven actuator or a bias member, thereby restraining or preventing the ULD  120  from translating in the opposite direction. 
     In various embodiments, the cargo handling system  100  may include a system controller  130  in communication with each of the plurality of PDUs  110  via a plurality of channels  132 . Each of the plurality of channels  132  may be a data bus, such as, for example, a controller area network (CAN) bus. An operator may selectively control operation of the plurality of PDUs  110  using the system controller  130 . In various embodiments, the system controller  130  may be configured to selectively activate or deactivate the plurality of PDUs  110 . Thus, the cargo handling system  100  may receive operator input through the system controller  130  to control the plurality of PDUs  110  in order to manipulate movement of the ULD  120  over the conveyance surface  102  and into a desired position on the cargo deck  112 . In various embodiments, the system controller  130  may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or some other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The cargo handling system  100  may also include a power source  126  configured to supply power to the plurality of PDUs  110  or to the plurality of restraint devices  114  via one or more power busses  128 . The system controller  130  may be complimented by or substituted with an agent-based control system, whereby control of each PDU and associated componentry—e.g., the restraint devices—is performed by individual unit controllers associated with each of the PDUs and configured to communicate between each other. 
     Referring now to  FIG.  2   , a PDU  210 , such as for example, one of the plurality of PDUs  110  described above with reference to  FIG.  1 B , is illustrated disposed in a tray  204 , in accordance with various embodiments. The PDU  210  may rotate the drive roller  208  in one of two possible directions (e.g., clockwise or counterclockwise) to move the ULD in a direction parallel to the longitudinal axis B-B′ of the tray  204  or in a direction that is perpendicular to the longitudinal axis B-B′. The PDU  210  may comprise a unit controller  240 , a unit motor  242  and a drive roller  208  mounted within an interior section  205  of the tray  204 . The drive roller  208  may comprise a cylindrical wheel coupled to a drive shaft and configured to rotate about an axis A-A′. The drive roller  208  may be in mechanical communication with the unit motor  242 , which may be, for example, an electromagnetic, electromechanical or electrohydraulic actuator or other servomechanism. The PDU  210  may further include gear assemblies and other related components for turning or raising the drive roller  208  so that the drive roller  208  may extend, at least partially, above a conveyance surface  202  which, in various embodiments, may be defined as the uppermost surface  203  of the tray  204 . At least partial extension of the drive roller  208  above the conveyance surface  202  facilitates contact between the drive roller  208  and a lower surface of a ULD, such as, for example, the ULD  120  described above with reference to  FIG.  1 B . In various embodiments, the unit controller  240  is configured to control operation of the drive roller  208 . The unit controller  240  may include a processor and a tangible, non-transitory memory. The processor may comprise one or more logic modules that implement logic to control rotation and elevation of the drive roller  208 . In various embodiments, the PDU  210  may comprise other electrical devices to implement drive logic. In various embodiments, a connector  244  is used to couple the electronics of the PDU  210  to a power source and a system controller, such as, for example, the system controller  130  described above with reference to  FIG.  1 B . The connector  244  may have pins or slots and may be configured to couple to a wiring harness having pin programing. The unit controller  240  may be configured to receive commands from the system controller through the connector  244  in order to control operation of the unit motor  242 . 
     In addition, a restraint device  214 , such as, for example, one of the plurality of restraint devices  114  described above with reference to  FIG.  1 B , is illustrated as disposed within the tray  204  and configured to operate between a stowed position, whereby the ULD may pass over the restraint device, and a deployed position (as illustrated), whereby the ULD is restrained or prevented from translation in a longitudinal direction (e.g., along a longitudinal axis B-B′) without the restraint device  214  first being returned to the stowed position. The restraint device  214  includes a restraint controller  215  and a restraint motor  217 . In various embodiments, the restraint device  214  may be in mechanical communication with the restraint motor  217 , which may be, for example, an electromagnetic, electromechanical or electrohydraulic actuator or other servomechanism. In various embodiments, the restraint controller  215  is configured to control operation of the restraint device  214 . The restraint controller  215  may include a processor and a tangible, non-transitory memory. The processor may comprise one or more logic modules that implement logic to control operation of the restraint device  214  between the stowed and the deployed positions. 
     In various embodiments, the PDU  210  may also include a radio frequency identification device or RFID device  246 , or similar device, configured to store, transmit or receive information or data — e.g., operational status or location data. Additionally, a ULD sensor  219  may be disposed within the tray  204  and configured to detect the presence of a ULD as the ULD is positioned over or proximate to the PDU  210  or the restraint device  214 . In various embodiments, the ULD sensor  219  may include any type of sensor capable of detecting the presence of a ULD. For example, in various embodiments, the ULD sensor  219  may comprise a proximity sensor, a capacitive sensor, a capacitive displacement sensor, a Doppler effect sensor, an eddy-current sensor, a laser rangefinder sensor, a magnetic sensor, an active or passive optical sensor, an active or passive thermal sensor, a photocell sensor, a radar sensor, a sonar sensor, a lidar sensor, an ultrasonic sensor or the like. 
     Referring now to  FIG.  3   , a schematic view of a cargo handling system  300  positioned on a cargo deck  312  of an aircraft is illustrated, in accordance with various embodiments. The cargo deck  312  may comprise a plurality of PDUs  310 , generally arranged in a matrix configuration about the cargo deck  312 . Associated with each of the plurality of PDUs  310  may be one or more drive rollers  308  and a restraint device  314 . In various embodiments, the plurality of PDUs  310 , the one or more drive rollers  308  and the restraint device  314  share similar characteristics and modes of operation as the PDU  210 , drive roller  208  and restraint device  214  described above with reference to  FIG.  2   . Each of the one or more drive rollers  308  is generally configured to selectively protrude from a conveyance surface  302  of the cargo deck  312  in order to engage with a surface of a ULD  320  as it is guided onto and over the conveyance surface  302  during loading and unloading operations. A plurality of conveyance rollers  306  may be arranged among the plurality of PDUs  310  in a matrix configuration as well. The plurality of conveyance rollers  306  may comprise passive elements, and may include roller ball units  307  that serve as stabilizing and guiding apparatus for the ULD  320  as it is conveyed over the conveyance surface  302  by the plurality of PDUs  310 . 
     In various embodiments, the cargo handling system  300  or, more particularly, the conveyance surface  302 , is divided into a plurality of sections. As illustrated, for example, the conveyance surface  302  may include a port-side track and a starboard-side track along which a plurality of ULDs may be stowed in parallel columns during flight. Further, the conveyance surface  302  may be divided into an aft section and a forward section. Thus, the port-side and starboard-side tracks, in various embodiments and as illustrated, may be divided into four sections—e.g., a forward port-side section  350 , a forward starboard-side section  352 , an aft port-side section  354  and an aft starboard-side section  356 . The conveyance surface  302  may also have a lateral section  358 , which may be used to transport the ULD  320  onto and off of the conveyance surface  302  as well as transfer the ULD  320  between the port-side and starboard-side tracks and between the aft section and the forward section. The configurations described above and illustrated in  FIG.  3    are exemplary only and may be varied depending on the context, including the numbers of the various components used to convey the ULD  320  over the conveyance surface  302 . In various embodiments, for example, configurations having three or more track configurations, rather than the two-track configuration illustrated in  FIG.  3   , may be employed. 
     Each of the aforementioned sections—i.e., the forward port-side section  350 , the forward starboard-side section  352 , the aft port-side section  354  and the aft starboard-side section  356 —may include one or more of the plurality of PDUs  310 . Each one of the plurality of PDUs  310  has a physical location on the conveyance surface  302  that corresponds to a logical address within the cargo handling system  300 . For purposes of illustration, the forward port-side section  350  is shown having a first PDU  310 - 1 , a second PDU  310 - 2 , a third PDU  310 - 3 , a fourth PDU  310 - 4 , a fifth PDU  310 - 5  and an N-th PDU  310 -N. The aforementioned individual PDUs are located, respectively, at a first location  313 - 1 , a second location  313 - 2 , a third location  313 - 3 , a fourth location  313 - 4 , a fifth location  313 - 5  and an N-th location  313 -N. In various embodiments, the location of each of the aforementioned individual PDUs on the conveyance surface  302  may have a unique location (or address) identifier, which, in various embodiments, may be stored in an RFID device, such as, for example, the RFID device  246  described above with reference to  FIG.  2   . 
     In various embodiments, an operator may control operation of the plurality of PDUs  310  using one or more control interfaces of a system controller  330 , such as, for example, the system controller  130  described above with reference to  FIG.  1 B . For example, an operator may selectively control the operation of the plurality of PDUs  310  through an interface, such as, for example, a master control panel (MCP)  331 . In various embodiments, the cargo handling system  300  may also include one or more local control panels (LCP)  334 . In various embodiments, the master control panel  331  may communicate with the local control panels  334 . The master control panel  331  or the local control panels  334  may also be configured to communicate with or send or receive control signals or command signals to or from each of the plurality of PDUs  310  or to a subset of the plurality of PDUs  310 , such as, for example, the aforementioned individual PDUs described above with reference to the forward port-side section  350 . For example, a first local control panel LCP- 1  may be configured to communicate with the PDUs residing in the forward port-side section  350 , a second local control panel LCP- 2  may be configured to communicate with the PDUs residing in the forward starboard-side section  352 , and one or more additional local control panels LCP-i may be in communication with the PDUs of one or more of the aft port-side section  354 , the aft starboard-side section  356  and the lateral section  358 . Thus, the master control panel  331  or local control panels  334  may be configured to allow an operator to selectively engage or activate one or more of the plurality of PDUs  310  to propel the ULD  320  along conveyance surface  302 . 
     In various embodiments, each of the plurality of PDUs  310  may be configured to receive a command from the master control panel  331  or one or more of the local control panels  334 . In various embodiments, the commands may be sent or information exchanged over a channel  332 , which may provide a communication link between the system controller  330  and each of the plurality of PDUs  310 . In various embodiments, a command signal sent from the system controller  330  may include one or more logical addresses, each of which may correspond to a physical address of one of the plurality of PDUs  310 . Each of the plurality of PDUs  310  that receives the command signal may determine if the command signal is intended for that particular PDU by comparing its own address to the address included in the command signal. 
     A cargo restraint is illustrated in  FIG.  4 A- 4 D , is identified by reference numeral  400 , and may be used in place of the restraint devices  114  of  FIG.  1 B , the restraint device  214  of  FIG.  2   , or by any other appropriate cargo handling system (e.g., for an aircraft). The cargo restraint  400  includes a pair of sidewalls  402  that are spaced from one another in a lateral or width dimension  416   b  for the cargo restraint  400 . Additional components of the cargo restraint  400  include an outer pawl or latch  480  (or a first pawl/latch  480 ) having a restraining head  482 , an inner pawl or latch  490  (or a second pawl/latch  490 ) having a restraining head  492 , and a retention pin  470 . 
     The cargo restraint  400  may be characterized as having a first end  404  and a second end  408  that are spaced from one another along a longitudinal dimension  416   a  of the cargo restraint  400 . Each sidewall  402  includes an aperture  410  that extends into/through the corresponding sidewall  402  for mounting of the noted retention pin  470  to the sidewalls  402 . The inner pawl  490  is pivotally connected to the sidewalls  402  by a pivot pin  496  and is movable between a retracted position (e.g.,  FIG.  6 A ) and an erected position (e.g.,  FIG.  10 A ) in a manner that will be discussed in more detail below. The inner pawl  490  includes a leg  494 , with the restraining head  492  being on a distal end of this leg  494 , and with the pivot pin  496  extending through a more proximal portion of the leg  494  and into/through an aperture  412  in the corresponding sidewall  402 . This pivotal connection between the inner pawl  490  and the sidewalls  402  is at a fixed location relative to the sidewalls  402  of the cargo restraint  400 —the location of the pivotal axis between the inner pawl  490  and the sidewalls  402  does not move during operation of the cargo restraint  400 . 
     The outer pawl  480  is also movably interconnected with the sidewalls  402 . In this regard, an inner surface  414  of each of the sidewalls  402  includes a similarly-configured slot or groove  420  that may be characterized as being cam-shaped—at least one surface of the slot  420  is shaped to induce a certain motion of the outer pawl  480  (more specifically its pivots  486 ) to change the elevation of a pivotal interconnection between the outer pawl  480  and the sidewalls  402  in a manner that will be discussed in more detail below. The outer pawl  480  includes a pair of legs  484  that are spaced in the lateral (or width) dimension  416   b . Each leg  484  includes a pivot  486  that extends into the slot  420  of the corresponding sidewall  402  and that is maintained in a fixed location on/along the corresponding leg  484  of the outer pawl  480 . The pivots  486  are movable along the length dimension of the corresponding slot  420  to change the elevation (in a vertical dimension  416   c ) of at least part of the outer pawl  480  and including the pivots  486 . The pivots  486  define a single pivot axis between the outer pawl  480  and the sidewalls  402 . 
     Details of the slot  420  in the inner surface  414  for one of the sidewalls  402  are presented in  FIG.  5 A . The slot  420  includes a lower sidewall  422  and an upper sidewall  424  that are spaced in the vertical dimension  416   c  for the cargo restraint  400 , along with a first end  430  and a second end  432  that are spaced in the longitudinal dimension  416   a  for the cargo restraint  400 . The lower sidewall  422  for each of the slots  420  includes a first segment  422   a  (e.g., a curved surface) that extends both upwardly (in the vertical dimension  416   c ) and in the longitudinal dimension  416   a  proceeding from the first end  430  (e.g., semi-circular) to a second segment  422   b  (a convex surface relative to the interior of the slot  420 ; an apex or a bump), along with a third segment  422   c  (e.g., a curved surface) that extends both downwardly (in the vertical dimension  416   c ) and also in the longitudinal dimension  416   a  proceeding from the second segment  422   b  to a fourth segment  422   d . The fourth segment  422   d  may be at least generally horizontally disposed but in any case extends in the longitudinal dimension proceeding from the third segment  422   c  to the second end  432  (e.g., semi-circular) of the slot  420 . 
     Continuing to refer to  FIG.  5 A , the upper sidewall  424  for each of the slots  420  includes a first segment  424   a  that extends from the first end  430  to a second segment  424   b  at least generally in the longitudinal dimension  416   a . The first segment  424   a  may be at least generally horizontally disposed. The second segment  424   b  may be curved (a concave surface relative to the interior of the slot  420 ). A third segment  424   c  (e.g., a curved surface) extends both downwardly (in the vertical dimension  416   c and in the longitudinal dimension  416   a  proceeding from the second segment  424   b  in the direction of the second end  432  of the slot  420 . The second end  432  again may be defined by a radius. The second end  432  may extend past a longitudinal position of the center of this radius to interconnect with the third segment  424   c  to define a stopper  426 . The stopper  426  may be convex relative to the interior of the slot  420 , and in any case should assist with retention of a corresponding pivot  486  (outer pawl  480 ) at the second end  432  of the slot  420  (e.g., the stopper  426  may provide a snap-lock of sorts to at least assisting with retaining a corresponding pivot  486  of the outer pawl  480  at the second end  432  of the slot  420  — a latched configuration for the outer pawl  480 ). 
     Representative pivot positions for a given pivot  486  (outer pawl  480 ) within a corresponding slot  420  are presented in  FIG.  5 B . In a first pivot position  450 , the pivot  486  is located at the intersection between the first end  430  of the slot  420  and the first segment  422   a  and that is in the form of a concave surface relative to the interior of the slot  420  (also referred to herein as a “home location  450 ”). In a second pivot position  452 , the pivot  486  is located on the second segment (apex or bump)  422   b  of the lower sidewall  422  of the slot  420  (also referred to herein as a “first location  452 ”). In a third pivot position  454 , the pivot  486  is positioned at an upper portion of the third segment  422   c  of the lower sidewall  422  of the slot  420 . In a fourth pivot position  456 , the pivot  486  is positioned at a lower portion of the third segment  422   c  of the lower sidewall  422  of the slot  420 . Finally, in a fifth pivot position  458  (also referred to herein as a “second location  458 ”), the pivot  486  is disposed at the second end  432  of the slot  420 . 
     A left end section of the slot  420  in the view of  FIG.  5 A  (including the first end  430  and extending in the direction of the bump or second segment  422   b ) may be characterized as a “retracted region” for the outer pawl  480 . A right end section of the slot  420  in the view of  FIG.  5 A  (including the fourth segment  422   c  and the second end  432 ) may be characterized as an “erected region” for the outer pawl  480 . An intermediate section of the slot  420 , that extends between the above-noted left end section and right end section of the slot  420 , and that includes the third segment  422   c , may be characterized as a “translation region” for the outer pawl  480 . Note in  FIG.  5 B  that the home location/first pivot position  450  is disposed at a lower elevation in the vertical dimension  416   c  compared to the first location/second pivot position  452 . As such, the elevation of the pivot  486  will be increased proceeding from the home location/first pivot position  450  to the first location/second pivot position  452 . The second location/fifth pivot position  458  is disposed at a lower elevation in the vertical dimension  416   c  compared to the first location/second pivot position  452  (the second location/fifth pivot position  458  is also disposed at a lower elevation in the vertical dimension  416   c  compared to the home location/first pivot position  450 ). As such, the elevation of the pivot  486  will be decreased proceeding from the first location/second pivot position  452  in the direction of the second location/fifth pivot position  458 . The pivot  486  will move primarily in the longitudinal dimension  416   a  (e.g., horizontally, if the cargo restraint  400  is disposed on a horizontal surface) when proceeding along the fourth segment  422   d  until engaging the second end  432 . 
       FIG.  6 A  illustrates the outer pawl  480  and the inner pawl  490  each being in a retracted position. At this time the pivots  486  for the outer pawl  480  are disposed in the home location/first pivot position  450  ( FIG.  6 B ). The pivots  486  are at least somewhat restrained in the longitudinal dimension  416   a  when disposed in the home location/first pivot position  450 . Note that a proximal end of the inner pawl  490  may be engaged with the retention pin  470  when it is fully retracted position. 
       FIG.  7 A  illustrates movement of the outer pawl  480  from the retracted position (also shown in  FIG.  6 A ) to an erected position. At this time the pivots  486  for the outer pawl  480  may remain in the home location/first pivot position  450  ( FIG.  7 B ). This movement of the outer pawl  480  is primarily a pivotal motion relative to the sidewalls  402  and about the pivots  486  (again defining a single pivotal axis between the outer pawl  480  and the sidewalls  402  of the cargo restraint  400 ). An operator may manually move the outer pawl  480  from the retracted position to the erected position in the direction indicated by the arrows shown in  FIG.  7 A . 
       FIG.  7 A  also illustrates a first structure or a until load device (ULD)  510 . A “ULD”, as used herein, includes a container, pallet, or other cargo of any size, shape, configuration, and/or type. A lower portion of the ULD  510  includes what may be characterized as a retention base, rim, rim segment, or flange  512 . Note that a lower surface of the retention base  512  is disposed at a higher elevation in the vertical dimension  416   c  than a conveyor plane  520  (e.g., typically due to the retention base  512  being bent or otherwise distorted—not shown in  FIG.  7 A ). This offset is identified by the double-headed arrow in  FIG.  7 A . The conveyor plane  520  at least generally corresponds with a surface (e.g., a cargo deck) along which the ULD  510  is moved in a cargo compartment. 
     A lower surface of the restraining head  482  of the outer pawl  480  in the  FIG.  7 A  configuration could be disposed at generally the same elevation (in the vertical dimension  416   c ) as a first or restrained surface  514  of the retention base  512 , could be disposed at a slightly higher elevation (in the vertical dimension  416   c ) compared to the restrained surface  514  of the retention base  512  ( FIG.  7 A ), or could even be disposed at a slightly lower elevation (in the vertical dimension  416   c ) compared to the restrained surface  514  of the retention base  512  (not shown). In any case, the restraining head  482  will typically be disposed in proximity to an outer perimeter of the retention base  512  in the configuration shown in  FIG.  7 A- 7 B . 
     An operator may lift the outer pawl  480 , from the erected position shown in  FIG.  7 A  to the position shown in  FIG.  8 A , to increase the elevation of the restraining head  482  of the outer pawl  480 . The entirety of the outer pawl  480  (including the pivots  486 ) may be moved in the vertical dimension  416   c  (as well as in the longitudinal dimension  416   a ) by the pivots  486  moving along the first segment  422   a  of the lower sidewall  422  of the slot  420  and with the outer pawl  480  being in the erected position. However, the outer pawl  480  could also be moved from its retracted position to its erected position in conjunction with moving the pivots  486  within the slot  420  from the first pin position  450  (e.g.,  FIGS.  6 A and  7 A ) to the second pin position  452  ( FIG.  8 B ). In any case, the noted movement of the outer pawl  480  disposes the pivots  486  at the first location/second pin position  452  shown in  FIG.  8 B  (at the second segment, apex, or bump  422   b ). Note the increased elevation of the restraining head  482  shown in  FIG.  8 A  compared to  FIG.  7 A  (i.e., a lower surface of the restraining head  482  is spaced further from the conveyor plane  520  in  FIG.  8 A  compared to  FIG.  7 A ), where the noted elevation increase is within the vertical dimension  416   c  and including such that the lower surface of the restraining head  482  is disposed at a higher elevation than the retention base  512  of the ULD  510  in the  FIG.  8 A  configuration. Further note that at least a distal portion of the restraining head  482  may be disposed in overlying relation (e.g., above) to the retention base  512  and including being in vertically spaced relation to the retention base  512  (with the pivots  486  being in the second pin position  452 ). 
     The entirety of the outer pawl  480  (including the pivots  486 ) may be moved downwardly in the vertical dimension  416   c  (as well as longitudinally in the longitudinal dimension  416   a ) by the pivots  486  moving along the third segment  422   c  of the lower sidewall  422  of the slot  420  and with the outer pawl  480  remaining in the erected position. This advances the pivots  486  (outer pawl  480 ) within the corresponding slot  420  from the first location/second pivot pin position  452  (e.g.,  FIG.  8 B ) at least generally in the direction of the second end  432  of the slot  420 , all as shown in  FIGS.  9 A and  9 B . The noted movement of the pivots  486  along the slot  420  (in the direction of the arrow B in  FIG.  9 A ), decreases the elevation (in the vertical dimension  416   c ) of the restraining head  482  (i.e., decreases the spacing between the lower surface of the restraining head  482  and the conveyor plane  520 ) to bring the restraining head  482  into engagement with the retention base  512  ( FIG.  9 A ). The initial engagement of the restraining head  482  with the retention base  512  may be when the pivots  486  are in the third pivot position  454  ( FIG.  9 B ), and further advancement of the pivots  486  along the slot  420  in the direction of the second end  432  of the slot  420  in the direction of the arrow B in  FIG.  9 A  (e.g., to dispose the pivots  486  at the fourth pin position  456  in  FIG.  9 B ) will further decrease the elevation (in the vertical dimension  416   c ) of the retention base  512  relative to the conveyor plane  520 . Note the reduction in the spacing between the lower surface of the retention base  512  and the conveyor plane  520  by comparison of  FIG.  8 A  (first location/second pin position  452 ) and  FIG.  9 B  (e.g., the fourth pin position  456 ). The outer pawl  480  also moves in the longitudinal dimension  416   a  in moving from the first location/second pin position  452  (e.g.,  FIG.  8 B ) to the fourth pin position  456  (e.g.,  FIG.  9 B ). That is, note the increase in the amount of the restraining head  482  of the outer pawl  480  that overlies the retention base  512  by a comparison of  FIG.  8 A  with  FIG.  9 A . 
     The above-noted movement of the outer pawl  480  from the  FIG.  8 A / 8 B position to the  FIG.  9 A / 9 B position also moves the inner pawl  490  away from its retracted position (e.g.,  FIG.  6 A ) and in the direction of its erected position (e.g.,  FIG.  10 A ). This is a due to an interconnection between the outer pawl  480  and the inner pawl  490  by one or more torsion springs  500  (e.g., a separate torsion spring  500  may be mounted on each pivot  486  of the outer pawl  480 ). The movement of the inner pawl  490  relative to the sidewalls  402  of the cargo restraint  400  is by a pivotal motion about the pivot pin  496  in the direction of the arrow A shown in  FIG.  9 A . 
     The entirety of the outer pawl  480  may be further advanced at least in the longitudinal dimension  416   a  to move the pivots  486  (outer pawl  480 ) within the slot  420  from the fourth pivot pin position  456  (e.g.,  FIG.  9 B ) at least generally in the direction of the second end  432  of the slot  420  to dispose the pivots  486  at the second end  432  of the slot  420 , all as shown in  FIGS.  10 A and  10 B . This movement of the outer pawl  480  may include an initial portion of movement of the pivots  486  along a distal portion of third segment  422   c  of the lower sidewall  422  of the slot  420 , which may further decrease the elevation (in the vertical dimension  416   c ) of the restraining head  482  (e.g., decreases the spacing between the lower surface of the restraining head  482  and the conveyor plane  520 ). In any case when the pivots  486  reach the fourth segment  422   d  of the lower sidewall  422  of the slot  420 :  1 ) the lower surface of the retention base  512  may be disposed at or in closely-spaced relation to the conveyor plane  520  ( FIG.  10 A ); and  2 ) the outer pawl  480  will thereafter primarily move in the longitudinal dimension  416   a  until reaching the fifth pin position  458  (e.g.,  FIG.  10 B ). Note the increase in the amount of the restraining head  482  of the outer pawl  480  that overlies the retention base  512  by a comparison of  FIG.  9 A  with  FIG.  10 A . Also note that the above-noted movement of the outer pawl  480  relative to the sidewalls  402  of the cargo restraint  400  also disposes the inner pawl  490  in its fully erected position of  FIG.  10 A  (via the above-noted spring(s)  500 ). The foregoing may be reversed to return the outer pawl  480  and the inner pawl  490  to their respective retractive positions of  FIG.  6 A  (the spring(s)  500  may bias the inner pawl  490  to its retracted position. 
     A method of using the cargo restraint  400  to restrain a ULD  510  in accordance with  FIGS.  6 A- 10 B  is illustrated in  FIG.  11    and is identified by reference numeral  530 . The method  530  includes moving a pivot  486  of the outer pawl  480  (e.g., a first movement; a movement of the pivot  486  at a first time) along its corresponding slot  420  to the first location  452  (step  532 ). The elevation of the pivot  486  of the outer pawl  480  may be increased by this first movement of the pivot  486  to the first location  452  (step  534 ). The outer pawl  480  may be disposed in an erect position, and with the pivot  486  being at the first location  452  the restraining head  482  of the outer pawl  480  may be disposed at a higher elevation than the surface  514  of the ULD  510  (step  536 ). The pivot  486  of the outer pawl  480  may be moved (e.g., a second movement; a movement of the pivot  486  at a second time that is different than the first time of step  532 ) along the corresponding slot  420  from the first location  452  to the second location  458  and with the outer pawl being  480  in the erect position (step  538 ). This second movement of the pivot  486  may decrease the elevation of the restraining head  482  of the outer pawl  480  (step  540 ). Such a decrease of the elevation of the restraining head  482  of the outer pawl  480  may engage the restraining head  482  against the surface  514  of the ULD  510  (step  542 ). 
     There are a number of points of note illustrated by the above-described operation of the cargo restraint  400 . One is that the pivots  486  of the outer pawl  480  are disposed on one side of the center of the pivot pin  496  (for the inner pawl  490 , and that remains in fixed location in the longitudinal dimension  416   a ) prior to the cargo restraint  400  being disposed in its fully latched configuration of  FIG.  10 A  (the “left side” of the center of the pivot pin  496  in the view shown in  FIGS.  6 A,  7 A,  8 A, and  9 A ). In the fully latched configuration of  FIG.  10 A , the center of the pivots  486  of the outer pawl  480  are now disposed on the opposite side of the center of the pivot pin  496  compared to the configurations of  FIGS.  6 A,  7 A,  8 A, and  9 A  (the center of the pivots  486  of the outer pawl  480  are disposed on the “right side” of the center of the pivot pin  496  in the fully latched configuration of  FIG.  10 A ). This is represented by the offset “OS” shown in  FIG.  10 A  and that assists with retaining the cargo restraint  400  in the fully latched configuration of  FIG.  10 A . The pivots  486  may also be at least somewhat “snap-locked” within the slot  420  at its second end  432  by the above-noted stopper  426  (that protrudes into the slot  420 ). 
     Any feature of any other various aspects addressed in this disclosure that is intended to be limited to a “singular” context or the like will be clearly set forth herein by terms such as “only,” “single,” “limited to,” or the like. Merely introducing a feature in accordance with commonly accepted antecedent basis practice does not limit the corresponding feature to the singular. Moreover, any failure to use phrases such as “at least one” also does not limit the corresponding feature to the singular. Use of the phrase “at least substantially,” “at least generally,” or the like in relation to a particular feature encompasses the corresponding characteristic and insubstantial variations thereof (e.g., indicating that a surface is at least substantially or at least generally flat encompasses the surface actually being flat and insubstantial variations thereof). Finally, a reference of a feature in conjunction with the phrase “in one embodiment” does not limit the use of the feature to a single embodiment. 
     The foregoing description has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and skill and knowledge of the relevant art, are within the scope of the present disclosure. Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Different cross-hatching is used throughout the figures to denote different parts but not necessarily to denote the same or different materials. 
     Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment,” “an embodiment,” “various embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
     Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Finally, it should be understood that any of the above described concepts can be used alone or in combination with any or all of the other above described concepts. Although various embodiments have been disclosed and described, one of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. Accordingly, the description is not intended to be exhaustive or to limit the principles described or illustrated herein to any precise form. Many modifications and variations are possible in light of the above teaching.