Patent Publication Number: US-11639279-B2

Title: System for transferring articles from a container

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 17/146,367, filed Jan. 11, 2021, entitled “SYSTEM FOR TRANSFERRING ARTICLES FROM A CONTAINER,” which is a continuation of U.S. patent application Ser. No. 16/124,070, filed Sep. 6, 2018, entitled “SYSTEM FOR TRANSFERRING ARTICLES FROM A CONTAINER,” which claims the benefit of U.S. Provisional Application Ser. No. 62/556,233, filed Sep. 8, 2017, entitled “AUTOMATED SYSTEM FOR TRANSFERRING ARTICLES FROM A CONTAINER,” U.S. Provisional Application Ser. No. 62/575,737, filed Oct. 23, 2017, entitled “SYSTEM FOR TRANSFERRING ARTICLES FROM A CONTAINER,” and U.S. Provisional Application Ser. No. 62/632,939, filed Feb. 20, 2018, entitled “SYSTEM FOR TRANSFERRING ARTICLES FROM A CONTAINER,” all of which are hereby incorporated by reference in their entirety and for all purposes. 
    
    
     FIELD 
     This disclosure relates to systems and methods for transfer of items between a first tray and a second tray. 
     DESCRIPTION OF THE RELATED TECHNOLOGY 
     Items, such as letters, envelopes, postcards, etc., may be received, transported, transferred, processed, collected, sorted, or the like, in containers such as trays. Items may be contained in different types of trays at various stages of transport and processing. 
     SUMMARY 
     The systems and methods of this disclosure each have several innovative aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope as expressed by the claims that follow, its more prominent features will now be discussed briefly. 
     In one aspect of the systems and methods disclosed herein, a tray content transfer system is described. The tray content transfer system comprises a frame configured to rotate about a rotation axis between an upright orientation and a rotated orientation; a first retainer coupled to the frame and configured to secure a first tray within the tray content transfer system, the first tray containing one or more items; a second retainer coupled to the frame and configured to secure a second tray within the tray content transfer system at a location spaced from the first tray along a longitudinal axis parallel to the rotation axis; a paddle assembly movably coupled to the frame, the paddle assembly comprising a plurality of paddles, wherein the distance between the paddles is adjustable to selectively engage and release items at least partially disposed between the paddles, and wherein the paddle assembly is movable relative to the frame along a first linear axis parallel to the longitudinal axis and a second linear axis perpendicular to the first linear axis; and a plurality of motors configured to adjust the distance between the paddles, to move the paddle assembly along the first linear axis and the second linear axis, and to rotate the frame about the rotation axis, in a predetermined sequence to transfer the one or more items from the first tray to the second tray. 
     In some embodiments, the predetermined sequence comprises, while the frame is in the upright orientation, causing the paddle assembly to engage the one or more items within the first tray; rotating the frame to the rotated orientation; moving the paddle assembly out of the first tray along the second linear axis; moving the paddle assembly along the first linear axis to a position proximate the second tray; moving the paddle assembly to a position at least partially within the second tray; rotating the frame to the upright orientation; and causing the paddle assembly to release the one or more items into the second tray. In some embodiments, the rotated orientation is rotated by at least 90° relative to the upright orientation. In some embodiments, the paddle assembly comprises a back plate disposed perpendicular to and at least partially between the paddles such that the one or more items rest at least partially on the back plate when the frame is in the rotated orientation. In some embodiments, the paddle assembly comprises a plurality of slidably offset back plates, each back plate in a fixed position relative to one of the plurality of paddles. In some embodiments, the slidably offset back plates are at least partially overlapping such that the slidably offset back plates span substantially the entire distance between the plurality of paddles. In some embodiments, the rotated orientation is rotated by more than 90° relative to the upright orientation, the paddle assembly further comprising a top plate disposed perpendicular to the back plate and disposed perpendicular to and at least partially between the paddles, such the back plate and the top plate retain the one or more items within the paddle assembly when the frame is in the rotated orientation. In some embodiments, the first retainer comprises at least one end pusher configured to space the one or more items from an inner wall of the first tray. In some embodiments, the end pushers are configured to simultaneously secure the first tray relative to the frame and to space the one or more items from the inner wall by moving inwardly through openings in side walls of the first tray. In some embodiments, the tray content transfer system further comprises a conveyor coupled to the frame, the conveyor configured to move a first tray or a second tray along the frame parallel to the longitudinal axis while the frame is in the upright orientation. In some embodiments, the tray content transfer system further comprises a sensor configured to detect the presence of the first tray or the second tray within the tray content transfer system, wherein the plurality of motors are configured to initiate the predetermined sequence based at least in part on detecting the presence of the first tray or the second tray. 
     In another aspect of the systems and methods disclosed herein, a method for transferring items from a tray is described. The method comprises, by an automated process, securing a first tray containing one or more items at a first location within a tray content transfer system; securing a second tray within the tray content transfer system at a second location spaced along a longitudinal axis from the first location; securing the one or more items relative to the first tray; rotating the first tray and the second tray simultaneously about a rotation axis parallel to the longitudinal axis from an upright orientation to a rotated orientation; while the first tray and the second tray are in the rotated orientation, moving the one or more items out of the first tray, moving the one or more items parallel to the longitudinal axis to a position adjacent to the second tray, and moving the one or more items into the second tray; rotating the first tray and the second tray simultaneously about the rotation axis from the rotated orientation to the upright orientation; releasing the one or more items into the second tray; and releasing the first tray and the second tray. 
     In some embodiments, the rotated orientation is rotated by at least 90° relative to the upright orientation. In some embodiments, the method further comprises engaging the one or more items between a plurality of paddles, wherein the one or more items remain engaged between the plurality of paddles while the first tray and the second tray are in the rotated orientation. In some embodiments, the method further comprises resting the one or more items on a substantially horizontal surface while the first tray and the second tray are in the rotated orientation. In some embodiments, securing the first tray comprises fixing the first tray relative to a frame of the tray content transfer system, and securing the second tray comprises fixing the second tray relative to the frame. In some embodiments, rotating the first tray and the second tray comprises rotating the frame about the rotation axis relative to a ground surface. In some embodiments, the method is initiated based at least in part on a detection of the presence of the first tray or the second tray within the tray content transfer system. In some embodiments, the second tray is an automation-compatible tray and the first tray is not an automation-compatible tray. 
     In another aspect of the systems and methods disclosed herein, a tray content transfer apparatus is described. The tray content transfer apparatus comprises means for securing a first tray and a second tray within the tray content transfer apparatus, the first tray containing one or more items; means for engaging the one or more items within the first tray; means for simultaneously rotating the first tray and the second tray about a horizontal rotational axis between an upright orientation and a rotated orientation; means for, while the first tray and the second tray are in the rotated orientation, removing the one or more items from the first tray along a first horizontal path, moving the items to a position proximate the second tray along a second horizontal path to a position adjacent to the second tray, and moving the items into the second tray along a third horizontal path parallel to the first horizontal path; and means for, while the first tray and the second tray are in the upright orientation, releasing the one or more items into the second tray. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. 
         FIG.  1    is a schematic illustration of an exemplary item processing system including a tray content transfer system. 
         FIG.  2 A  is a front perspective view of an exemplary tray content transfer system. 
         FIG.  2 B  is a rear perspective view of the tray content transfer system of  FIG.  2 A . 
         FIG.  2 C  is a perspective view of a paddle assembly component of the tray content transfer system depicted in  FIGS.  2 A and  2 B . 
         FIG.  2 D  is a front elevation view of the tray content transfer system of  FIGS.  2 A and  2 B  showing the axes of motion of the tray content transfer system. 
         FIG.  3    is a perspective view of an initial state of a tray content transfer system during an exemplary tray content transfer process. 
         FIG.  4    is a perspective view of a second state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIG.  3   . 
         FIG.  5    is a perspective view of a third state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 4   . 
         FIG.  6    is a perspective view of a fourth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 5   . 
         FIGS.  7 A and  7 B  are perspective views of a fifth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 6   . 
         FIG.  8    is a perspective view of a sixth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 7   . 
         FIG.  9    is a perspective view of a seventh state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 8   . 
         FIG.  10    is a perspective view of an eighth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 9   . 
         FIG.  11 A  is a rear perspective view of a ninth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 10   . 
         FIG.  11 B  is a front perspective view of the ninth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 11 A . 
         FIG.  12    is a perspective view of a tenth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 11 B . 
         FIG.  13    is a perspective view of an eleventh state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 12   . 
         FIG.  14    is a perspective view of a twelfth state of the tray content transfer system of  FIG.  3    during the exemplary tray content transfer process of  FIGS.  3 - 13   . 
         FIG.  15    is a block diagram of a tray content transfer system. 
         FIG.  16    is a flowchart illustrating an exemplary method of initiating the transfer of items from a container. 
         FIG.  17    is a flowchart illustrating an exemplary method of transferring items from a source tray to a process tray in a tray content transfer system. 
         FIG.  18    is a front perspective view of an exemplary tray content transfer system. 
         FIG.  19    is a perspective view of an initial state of a tray content transfer system during an exemplary tray content transfer process. 
         FIG.  20    is a perspective view of a second state of the tray content transfer system of  FIG.  19    during the exemplary tray content transfer process of  FIG.  19   . 
         FIG.  21    is a perspective view of a third state of the tray content transfer system of  FIG.  19    during the exemplary tray content transfer process of  FIGS.  19 - 20   . 
         FIG.  22    is a perspective view of a fourth state of the tray content transfer system of  FIG.  19    during the exemplary tray content transfer process of  FIGS.  19 - 21   . 
         FIG.  23 A  is a front perspective view of an exemplary tray content transfer system. 
         FIG.  23 B  is a front perspective view of an exemplary process tray compatible with the tray content transfer systems described herein. 
         FIG.  24    is a perspective view of an initial state of a tray content transfer system during an exemplary tray content transfer process. 
         FIG.  25    is a perspective view of a second state of the tray content transfer system of  FIG.  24    during the exemplary tray content transfer process of  FIG.  24   . 
         FIG.  26    is a perspective view of a third state of the tray content transfer system of  FIG.  24    during the exemplary tray content transfer process of  FIGS.  24 - 25   . 
         FIG.  27    is a perspective view of a fourth state of the tray content transfer system of  FIG.  24    during the exemplary tray content transfer process of  FIGS.  24 - 26   . 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Thus, in some embodiments, part numbers may be used for similar components in multiple figures, or part numbers may vary from figure to figure. The illustrative embodiments described herein are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations by a person of ordinary skill in the art, all of which are made part of this disclosure. 
     Reference in the specification to “one embodiment,” “an embodiment”, or “in some embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Moreover, the appearance of these or similar phrases throughout the specification does not necessarily mean that these phrases all refer to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive. Various features are described herein which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but may not be requirements for other embodiments. 
     In processing items in a distribution network, items can be transported in containers, such as trays. Items such as letters, postcards, envelopes, or other stackable items may be received, transported, and processed in trays. In some item processing implementations, two or more different types of trays may be used. For example, items may be received in a first type of tray which may be optimized for transport of items outside of a processing facility (e.g., may be flexible, lightweight, inexpensive to manufacture, sized and shaped to fit in an item collection system, or the like). When a tray of items is received at a processing facility, a second type of tray may be better suited for transport of the items within the facility for processing. For example, a second type of tray may be configured to be compatible with automated processing machinery at the processing facility (e.g., may have structural features designed to interact with particular processing machines and/or may be more rigid or dimensionally stable to facilitate automated processing of items). Thus, items received in the first type of tray may need to be transferred to the second type of tray before at least a portion of the desired processing occurs. 
     Transferring items between trays such as from soft-sided intake trays to rigid automation-friendly processing trays can be performed manually. Manual transfer of items from a first tray to a second tray can be time-consuming and imprecise. Items may be dropped while being manually transferred, for example, while an operator is moving a horizontally oriented stack of letters by exerting an inward pressure on the ends of the stack. In another example, items such as letters may be received in a uniformly faced arrangement, and operator error during transfer may cause some of the letters to face the opposite direction after transfer, resulting in processing errors or delays. 
     The tray content transfer systems disclosed herein are configured to provide an automated process for transferring items from a first tray to a second tray. In some embodiments, the tray content transfer systems may transfer items more reliably, efficiently, cost-effectively, and/or quickly than existing manual methods of tray content transfer. Although the present disclosure describes tray content transfer systems in the context of trays and flat items such as letter mail, it will be understood that other containers and items can be used without departing from the scope of the present disclosure. 
     Generally described, embodiments of the systems described herein use a combination of rotational and linear motion to reliably and efficiently transfer items between a source tray, such as a letter tray, and a process tray better suited for use with further processing of the items, such as a rigid tray. For example, the items may be transferred to an automation-compatible tray from a source tray that is not an automation-compatible tray. In some embodiments, a loaded source tray and an empty process tray are secured within a rotatable frame while the frame is in an upright orientation. A paddle assembly descends to a position partially within the loaded source tray, such that the contents of the source tray are between the paddles of the paddle assembly, and squeezes the paddles together to gently clasp or otherwise engage the contents. The frame then rotates approximately 90° to 100° to a rotated orientation such that the contents are resting on a rear surface of the paddle assembly and not on the bottom surface of the source tray. The paddle assembly then moves linearly out of the source tray, moves linearly to a position adjacent to the process tray, and moves linearly into the process tray such that the contents are generally within the process tray. The frame then rotates back to the upright orientation and the paddles are moved apart to release the contents into the process tray. The combination of rotational and linear motion can advantageously allow the transfer system to move articles such as letters from a first tray to a second tray without lifting or suspending the articles over a space between the trays, where articles may be lost if dropped. 
       FIG.  1    schematically illustrates an example item processing system  100  including a tray content transfer system  105 . The item processing system  100  further includes a source tray intake  110 , processing apparatus  120 , an empty source tray collection  130 , and an empty process tray supply  140 . Trays can be transferred between the components of the item processing system  100  by an intake flow path  115 , an output flow path  125 , an empty source tray flow path  135 , and an empty process tray flow path  145 . Each of the flow paths  115 ,  125 ,  135 ,  145  can be a conveyor, such as a moving conveyor belt surface, a series of rollers, or any other conveying system configured to move one or more trays laterally and/or vertically. 
     The source tray intake  110  can include one or more devices or systems for providing item-containing source trays. For example, the source tray intake  110  can include a loading dock where item-containing trays are received from transport vehicles for processing. In some embodiments, the source tray intake  110  can be an output of another process to be performed before tray content transfer. For example, in some letter mail processing embodiments, the source tray intake  110  may include a facer-canceler system configured to apply a cancellation to letters and place the letters in a uniformly faced horizontal stack within source trays. 
     The processing apparatus  120  can include one or more devices or systems for processing the items after tray content transfer. For example, the processing apparatus  120  can include any number of machines configured to scan, weigh, measure, sort, order, combine, separate, analyze, or otherwise process the items. In some letter mail processing embodiments, the processing apparatus  120  can include one or more machines for automatically reading information provided on the letters (e.g., postage information, destination address, return address, etc.) and/or sorting the letters for further transportation. 
     The empty source tray collection  130  and empty process tray supply can include one or more lines, piles, stacks, carts, dispensers, receivers, or other structures capable of holding a plurality of trays. For example, the empty source tray collection  130  may include a tray receiving system located at an end of the empty source tray flow path  135  for receiving and stacking or otherwise organizing empty source trays to be reused for transporting additional items. The empty process tray supply  140  can include one or more stacks, dispensers, or the like, for placing empty process trays into the empty process tray flow path  145  for delivery to the tray content transfer system  105 . 
     In an exemplary method of operation, the tray content transfer system  105  receives an item-containing source tray from the source tray intake  110  via the intake flow path  115 , and receives an empty process tray from the empty process tray supply  140  via the empty process tray flow path  145 . At the tray content transfer system  105 , the items in the source tray are transferred from the source tray to the empty process tray. After the transfer, the process tray contains the items previously received in the source tray. The item-containing process tray is then sent to the processing apparatus  120  via the output flow path  125 . The empty source tray is sent to the empty source tray collection  130  via the empty source tray flow path  135 . After the source tray and process tray leave the tray content transfer system  105 , the example method can be repeated with a second item-containing source tray and a second empty process tray. 
     The exemplary method described above with reference to  FIG.  1    can be repeated any number of times or indefinitely, for example, based on a desired number or rate of item-containing source trays received for processing. In some embodiments, the tray content transfer system  105  can be configured to transfer the contents of two or more source trays to a single process tray, to transfer the contents of a single source tray to two or more process trays, or to transfer the contents of two or more source trays to two or more process trays simultaneously. In addition, various components of the item processing system  100  can be automated and/or performed manually. For example, any of the flow paths  115 ,  125 ,  135 ,  145  can be performed manually at least in part, such as by an operator manually placing one or more loaded or empty trays onto a conveyor or directly into the tray content transfer system  105 . 
       FIGS.  2 A- 2 D  depict a tray content transfer system  200  in accordance with an exemplary embodiment.  FIGS.  2 A and  2 B  are front and rear perspective views of the tray content transfer system  200  in an empty state.  FIG.  2 C  is a rear perspective view of a paddle assembly  240 , a component of the tray content transfer system  200 .  FIG.  2 D  is a front elevation view of the tray content transfer system  200  containing a source tray  280  and a process tray  290 , illustrating three axes of motion within the tray content transfer system  200 . The tray content transfer system  200  generally includes an outer frame  210 , a rotation frame  220  movably mounted at least partially within the outer frame  210 , and the paddle assembly  240  movably mounted on the rotation frame  220 . 
     The outer frame  210  is generally configured to provide a stable support for the rotation frame  220 . The outer frame  210  includes various structural members  212  arranged to form a substantially rigid frame structure, two pivot points  214 , and two vertical tracks  216 . As will be described with reference to the rotation frame  220 , the pivot points  214  and the vertical tracks  216  are configured to accommodate and/or at least partially actuate rotational motion of the rotation frame  220  about a rotation axis defined by the two pivot points  214 . In various embodiments, the outer frame  210  can be any size, shape, or configuration suitable to support the rotation frame  220 . For example, the outer frame  210  can be built into a wall, a shelf, a floor, or the like, and need not be a free-standing rectangular frame as shown in the figures. 
     The rotation frame  220  includes a horizontal sub-frame  222  and a vertical sub-frame  224  rigidly and perpendicularly mounted to the horizontal sub-frame  222 . The horizontal sub-frame  222  is configured to receive and secure a source tray  280  and a process tray  290 , as will be described herein below with reference to  FIG.  2 D . Two slidable end pushers  226  are mounted in a spaced configuration on the horizontal sub-frame  222  to act as a retainer for a source tray  280 , such that a source tray, for example, a plastic postal tray, can be placed between the end pushers  226  and secured to the horizontal sub-frame  222  by sliding the end pushers  226  inward such that the end-pushers  226  extend through holes in the sidewalls of the source tray  280 . The inner ends of the end-pushers  226  can be squared, or may be rounded, chamfered, beveled, filleted, bullet-shaped, or otherwise shaped so as to facilitate entry of the end pushers  226  into the holes of source trays  280 , for example, to accommodate incorrect alignment of a source tray  280  with the end pushers  226 . In some embodiments, the end pushers  226  may be external clamps that do not pass through holes in the source tray  280 . Brackets  223  may be provided to facilitate horizontal alignment of the trays. Actuators may be provided within the system  200  (e.g., attached to the horizontal sub-frame  222 ) to move the end pushers  226 . 
     Process tray clamps  228  are provided as a retainer for securing a process tray  290  to the horizontal sub-frame  222 . The process tray clamps  228  further include compressible feet  230  (e.g., rubber discs or the like), and are mounted in a spaced configuration on the horizontal sub-frame  222  such that a process tray  290 , for example, a rigid automation-friendly processing tray, can be placed between the process tray clamps  228  and secured to the horizontal sub-frame  222  by sliding the process tray clamps  228  inward until they contact opposing sides of the process tray  290 . The compressible feet  230  can provide an inward pressure and static friction against opposite sides of the process tray  290  to hold the process tray  290  in place. Actuators may be provided within the system  200  (e.g., attached to the horizontal sub-frame  222 ) to move the process tray clamps  228 . In some embodiments, one or more conveyors  221  are located on or near the horizontal sub-frame  222  and configured to slide a process tray  290  when the process tray  290  is located at least partially on the conveyors  221 . The conveyors  221  may be reversible, for example, so that they can travel in a first direction before a transfer to pull a process tray  290  from an external conveyor system (e.g., an automated tray transport system or the like) into a suitable position between the process tray clamps  228 , and can travel in a second direction after completing a transfer to push the process tray  290  back out to the external conveyor system. It will be understood that one or more additional conveyors similar to conveyors  221  may similarly be implemented for source trays  280 . 
     The vertical sub-frame  224  of the rotation frame  220  is generally configured to support and move the paddle assembly  240 . A horizontal translation platform  232  is slidably mounted to a horizontal track member  234  of the vertical sub-frame  224  to accommodate horizontal movement of the paddle assembly  240 . A vertical translation platform  236  is slidably mounted to two vertical track members  238  of the horizontal translation platform  232  to accommodate vertical movement of the paddle assembly  240 . Movement of the horizontal translation platform  232  along the horizontal track member  234  and movement of the vertical translation platform  236  along the vertical track members  238  can occur independently, and may be controlled by one or more motors. 
     The rotation frame  220  is configured to rotate relative to the outer frame  210  as indicated by arrow  251  in  FIGS.  2 A and  2 B . Thus, the rotation frame  220  further includes two rotation hinges  250  and two vertical sliders  252  connected to the horizontal sub-frame  222  by legs  254  coupled to the horizontal sub-frame  222  at leg hinges  256 . When the rotation frame  220  is to be rotated, the vertical sliders  252  can be driven upward along the vertical tracks  216 , for example, by one or more motors, applying a generally upward force on the horizontal sub-frame  222 . The generally upward force on the horizontal sub-frame  222  causes a torque at the axis of rotation along the pivot points  214 , such that the rotation frame  220  rotates backward (e.g., clockwise in the perspective view of  FIG.  2 A ) about the axis of rotation. The hinges  250  interlock with the pivot points  214  to secure the rotation frame  220  to the outer frame  210  along the axis of rotation. The rotation frame  220  may have a maximum range of rotational motion, for example, defined between the positions of the rotation frame  220  when the vertical sliders  252  are at the bottom and top ends of the vertical tracks  216 . 
     The paddle assembly  240 , as shown in  FIGS.  2 A- 2 C , includes two paddles  242 , top plates  244 , and back plates  245 . The paddle assembly  240  can be made of any substantially rigid material, for example, a metal such as sheet aluminum or steel, a hard plastic, or the like. In some embodiments, at least a portion of the paddle assembly  240 , for example, top plates  244  and/or back plates  245 , may comprise a less rigid material such as cardboard, corrugated plastic, or the like. In the example embodiment depicted in  FIGS.  2 A- 2 D , each top plate  244  is adjacent to and overlapping the other top plate  244 , and each back plate  245  is adjacent to and overlapping the other back plate  245 , such that the top plates  244  and back plates  245  can remain in contact and span substantially the entire distance between the paddles  242  as the paddles  242  slide together or apart. 
     A paddle slider  246  is slidably mounted to a paddle assembly track member  248  of the vertical translation platform  236 . The paddle slider  246  is rigidly coupled to one of the paddles  242 , such that motion of the paddle slider  246  along the paddle assembly track member  248  causes the paddle  242  to move inward or outward relative to the other paddle  242 . In some embodiments, both paddles  242  can be movable inward and outward, or one of the paddles  242  can be stationary with the distance between the paddles adjusted by moving a single paddle  242  relative to the other paddle  242 . 
     Each paddle  242  is a generally planar surface disposed perpendicular to the top plates  244  and back plates  245 . The paddles  242  include angled edges  241 , providing a reduced paddle width at the lower end of the paddles  242  to facilitate placement of the paddle into a tray. For example, in embodiments compatible with corrugated plastic postal letter trays as source trays  280 , the angled edges  241  may be configured to substantially match the angle of the sidewalls of the letter trays. Each paddle  242  further includes a cutout  243  extending upward from a bottom edge of the paddle  242 . The cutout  243  has a width slightly larger than the width of the end pushers  226  of the rotation frame  220 , such that an end pusher  226  can be accommodated within the cutout  243  and avoid impeding downward motion of the paddle  242  when the paddle  242  is lowered into a source tray  280 . In various embodiments, the paddles  242  can have other sizes and/or shapes to conform with source trays  280  of any size or shape. 
     Referring now to  FIG.  2 D , the components described above with reference to  FIGS.  2 A- 2 C  can move the paddles  242  of the paddle assembly  240  along several axes within the reference frame of the rotation frame  220 . Horizontal translation along an axis  233  of the paddle assembly  240  can be achieved by moving the horizontal translation platform  232  along the horizontal track member  234 . Vertical translation along an axis  237  of the paddle assembly  240  can be achieved by moving the vertical translation platform  236  along the vertical track members  238 . Squeezing of the paddles  242  along an axis  247  can be achieved by moving the paddle slider  246  along the paddle assembly track member  248 . A combination of movements along axes  233 ,  237 , and  247  can be used to transfer items from the source tray  280  to the process tray  290 . 
     Referring generally to  FIGS.  2 A- 2 D , motion of any of the moving parts described herein, for example, end pushers  226 , process tray clamps  228 , horizontal translation along the axis  233 , vertical translation along the axis  237 , squeezing of the paddles  242  along the axis  247 , and/or rotation of the rotation frame  220  within the outer frame, can be driven by any number of motors  260 , and can be selectively controlled and/or inhibited by mechanical brakes configured to stop and/or prevent motion along any of the movement axes described herein. The motors  260  and/or brakes can be controlled by one or more controllers, which may include computer components such as one or more processors, memory or other storage media, network or other communication interfaces, and/or other circuitry. In some embodiments, a memory of the controller stores computer-executable instructions that, when executed by the processor and/or other circuitry of the controller, directly or indirectly cause the motors and/or brakes to move in a predetermined sequence. The predetermined sequence can include, for example, a tray content transfer process such as the process described below with reference to  FIGS.  3 - 14   . 
       FIGS.  3 - 14    sequentially illustrate an example process for transferring the contents of a source tray  280  to a process tray  290 . Although the process of  FIGS.  3 - 14    is shown and described in the context of the tray content transfer system  200  depicted in  FIGS.  2 A- 2 D , it will be appreciated that the same or similar steps may be implemented in any other tray content transfer system. 
       FIG.  3    depicts an initial state of the tray content transfer process. In the initial state, a source tray  280  contains items  205 . The items can be, for example, letters, flats, etc. In the initial state of  FIG.  3   , the source tray  280  has been placed onto the horizontal sub-frame  222  of the rotation frame  220  between the end pushers  226 , which are in an open configuration. An empty process tray  290  has been placed in the horizontal sub-frame  222  between the process tray clamps  228 , which are in an open configuration. As described above with reference to  FIG.  1   , the source tray  280  and the process tray  290  may have been placed in their respective locations manually or automatically, for example, being placed into the tray content transfer system  200  by one or more conveyors, rollers, ramps, robotic arms, paddles, pushers, or other automated tray placement mechanism. The paddle assembly  240  is located above the source tray  280  with the paddles in an open configuration. The rotation frame  220  is in an upright configuration. 
     In the example tray content transfer process, the source tray  280  is a corrugated plastic postal letter tray for the transportation of letter mail. The process tray  290  is a rigid plastic automation-friendly tray including various features optimized for transfer of the items  205  between various letter processing machinery located elsewhere. The items  205  stacked within the source tray  280  are to be transferred to the process tray  290 . In some embodiments, the items  205  may already be uniformly faced (that is, selectively flipped such that the postage and address of each item in the stack faces the same direction). Thus, it is desirable for the tray content transfer process to maintain the uniform facing of the items  205  during transfer. 
     Referring now to  FIG.  4   , after the source tray  280  and the process tray  290  have been placed into the tray content transfer system  200 , the end pushers  226  move inward through holes  282  in the ends of the source tray  280 , such that a portion of each end pusher  226  extends into the interior space of the source tray  280 . At an intermediate point along the inward trajectory of the end pushers  226 , they contact the stack of items  205 . With continued inward motion, the end pushers  226  can compress the stack of items  205 , causing the items  205  to move to a more vertical orientation. In compressing the stack, the end pushers  226  push the items  205  toward the middle of the source tray  280  and away from the ends, creating a space between the items  205  and the interior end walls  284  of the source tray  280 . In various embodiments, the inward distance traveled by each end pusher  226  can be, for example, 1 inch, 2 inches, 3 inches, 4 inches, or more. 
     In addition, the process tray clamps  228  move inward against the process tray  290  to secure the process tray  290  in position. 
     After the end pushers  226  are inserted, the process continues to the configuration shown in  FIG.  5   . As shown in  FIG.  5   , the vertical translation platform  236  slides downward along the axis  237 , along the vertical track members  238  such that the paddle assembly  240  moves downward along the axis  237  to a location partially within the source tray  280 . The paddles  242  of the paddle assembly  240  are spaced such that each paddle  242  descends into one of the empty spaces between the items  205  and an interior end wall  284  of the source tray  280 . The end pushers  226  are accommodated within the cutouts  243  (shown in  FIG.  2 C ) of the paddles  242  such that lower ends of the paddles  242  can descend to a position at or near the bottom of the source tray  280  (e.g., within 1 inch, ½ inch, ¼ inch, or closer). Thus, in the state shown in  FIG.  5   , the stack of items  205  is disposed between the two paddles  242 . 
     After the paddle assembly  240  is lowered into the source tray  280 , the process continues to the configuration shown in  FIG.  6   . As shown in  FIG.  6   , the paddle slider  246  has moved inward along the axis  247  along the paddle assembly track member  248  such that the top plates  244  slide over each other and at least one of the paddles  242  moves inward to squeeze the paddles  242  closer together. The paddles  242  can be moved together a suitable distance such that each paddle  242  is in contact with an end of the stack of items  205 . In some embodiments, the end pushers  226  can move outward a short distance so as to reduce the inward pressure on the stack. In the state shown in  FIG.  6   , the items  205  are substantially confined between the paddles  242 , the bottom of the source tray  280 , and the top plates  244  and back plates  245  of the paddle assembly  240 . 
     After the paddles  242  move inward to contain the stack of items  205 , the process continues to the configuration shown in  FIGS.  7 A and  7 B . As shown in  FIGS.  7 A and  7 B , the entire rotation frame  220  has rotated backward about the axis of rotation between the hinges  250 . In some embodiments, the rotation frame  220  rotates approximately 90° or more, for example, any angle within the range of approximately 95°, 100°, 105°, or more, such that the horizontal sub-frame  222  is in a generally vertical orientation (e.g., angled between approximately 70° and 90° relative to the outer frame  210  and/or the ground) and the vertical sub-frame  224  is in a generally horizontal orientation (e.g., angled between approximately 0° and 20° relative to the outer frame  210  and/or the ground). In some embodiments, the rotation frame  220  can rotate less than 90°, for example, in the range of 85°, 80°, 75°, or less. Rotation of the rotation frame  220  may be actuated by one or more motors, for example, pushing the vertical sliders  252  upward along the vertical tracks  216  to impart a rotational force about the rotation hinges  250  through the legs  254 . 
     As shown in  FIGS.  7 A and  7 B , the components within the rotation frame  220  and paddle assembly  240  are in substantially the same configuration as in the state shown in  FIG.  6   . After rotation of the rotation frame  220 , the items  205  are generally resting on the back plates  245  (not visible in  FIGS.  7 A and  7 B ) of the paddle assembly  240 . If the end pushers  226  did not move partially outward at the stage depicted in  FIG.  6   , the end pushers  226  can move outward to reduce the pressure exerted against the items  205 . It may be desirable for the end pushers  226  to remain partially inserted such that at least a portion of the end pushers still extends through the holes  282  to prevent the source tray  280  from falling out of position. 
     After rotation of the rotation frame  220 , the process continues to the configuration shown in  FIG.  8   . As shown in  FIG.  8   , the vertical translation platform  236  has slid back along the axis  237 , along the vertical track members  238  such that the paddle assembly  240  and items  205  held therein withdraw from the source tray  280 . Generally, the paddle assembly  240  travels a distance sufficient to allow all items  205  and the paddles  242  to be outside of the inner space defined by the source tray  280 . In some aspects, the step of withdrawing the items  205  from the source tray  280  may be facilitated when the angle of rotation in  FIGS.  7 A and  7 B  is greater than 90°, as the back plates  245  (not visible in  FIG.  8   ) are sloped downward away from the source tray  280  such that a letter  205  that may fall out of the stack will tend to fall into the paddle assembly  240 , rather than into the space between the paddle assembly  240  and the source tray  280  where the letter  205  could be lost. 
     After sliding of the vertical translation platform  236 , the process continues to the configuration shown in  FIG.  9   . As shown in  FIG.  9   , after the items  205  are withdrawn from the source tray  280 , the horizontal translation platform  232  has traveled along the axis  233 , along the horizontal track member  234  to move the paddle assembly  240  containing items  205  to a position adjacent to the process tray  290 . During the horizontal translation, the items  205  are held in place relative to the paddle assembly  240  by the paddles  242  and the back plates  245  (not visible in  FIG.  9   ). After the paddle assembly  240  is moved horizontally to a position adjacent to the process tray  290 , the process continues to the state depicted in  FIG.  10   . 
     As shown in  FIG.  10   , the vertical translation platform  236  has moved along the axis  237 , along the vertical track members  238  to position the paddle assembly  240  and items  205  at least partially within the process tray  290 . The direction and distance traveled by the vertical translation platform  236  may be similar or identical to the direction and distance traveled by the vertical translation platform  236  between  FIG.  4    and  FIG.  5   . After the items  205  and paddle assembly  240  have been moved into the process tray  290  as shown in  FIG.  10   , the process continues to the state depicted in  FIGS.  11 A and  11 B . 
     As shown in  FIGS.  11 A and  11 B , the entire rotation frame  220  has rotated forward about the hinges  250  along the axis between the pivot points  214 . In some embodiments, the rotation frame  220  travels the same angular distance traveled between  FIG.  6    and  FIGS.  7 A and  7 B  (e.g., 90°, 95°, 100°, 105° or more) such that the rotation frame  220  is returned to its initial rotational state. Thus, the horizontal sub-frame  222  is again in a generally horizontal orientation, and the vertical sub-frame  224  is again in a generally vertical orientation. Rotation of the rotation frame  220  back to its initial rotational state may be actuated by one or more motors, for example, pushing the vertical sliders  252  downward along the vertical tracks  216  to impart a rotational force about the rotation hinges  250  through the legs  254 . 
     As shown in  FIGS.  11 A and  11 B , the components within the rotation frame  220  and paddle assembly  240  are in substantially the same configuration as the state shown in  FIG.  10   . After rotation of the rotation frame  220 , the items  205  are generally resting on the bottom interior surface of the process tray  290 . After rotation of the rotation frame  220  as shown in  FIGS.  11 A and  11 B , the process continues to the configuration shown in  FIG.  12   . 
     Referring now to  FIG.  12   , the paddle slider  246  has moved outward along the axis  247 , along the paddle assembly track member  248  such that at least one of the paddles  242  moves outward (e.g., away from the other paddle  242 ) to release the stack of items  205 , allowing the items  205  to rest on the bottom interior surface of the process tray  290  without being held in a vertical orientation by the paddles  242 . After the paddles  242  move outward, the process continues to the configuration shown in  FIG.  13   . 
     Referring now to  FIG.  13   , the vertical translation platform  236  slides upward along axis  237 , along the vertical track members  238  such that the paddle assembly  240  moves upward to a position clear of the items  205  and the process tray  209 . In some embodiments, the vertical translation platform  236  can move fully upward to its initial vertical position as shown in  FIG.  3   . Once the paddles  242  are removed from the process tray  290  and the items  205  fall into a slanted stack within the process tray  290 , the items  205  and process tray  290  are in a suitable configuration for further processing. 
     Continuing to  FIG.  14   , the tray content transfer system returns to its initial state such that the source tray  280  and process tray  290  can be removed. The horizontal translation platform  232  travels along the horizontal track member  234  to move the paddle assembly  240  back to its initial position above the source tray  280  as shown in  FIG.  3   . The end pushers  226  and process tray clamps  228  move outward to release the source tray  280  and process tray  290 . Accordingly, the now-empty source tray  280  and the process tray  290  containing the items  205  can be removed from the tray content transfer system  200 , and the tray content transfer process can be repeated indefinitely as additional source trays  280  arrive with contents to be transferred. 
       FIG.  15    is a block diagram of a tray content transfer system  1500  in accordance with an exemplary embodiment. The system  1500  includes a sensor  1510  in communication with a CPU  1520 . The CPU  1520  is further in communication with a memory  1530  and actuators including actuator  1   1540 , actuator  2   1550 , actuator  3   1560 , actuator  4   1570 , actuator  5   1580 , and actuator  6   1590 . Although the system  1500  is depicted as having 6 actuators, the number of actuators in various embodiments can be greater or smaller than 6, for example, based on the number of parts to be moved in any particular embodiment of the system  1500 . 
     The sensor  1510  is configured to detect the presence of one or more containers or other objects within the system  1500 . For example, the sensor  1510  can be configured to detect the presence of a source tray and/or a process tray before initiating a transfer process. In various implementations, the sensor  1510  can include one or more proximity sensors, profile sensors, pressure sensors, force sensors, scales, cameras, optical pattern recognition devices such as barcode scanners, light gates, or the like. In some embodiments, the sensor  1510  can include a manually activated device, such as a button, configured to produce a signal indicating that a source tray and a process tray have been loaded into the system  1500 . In some embodiments, the sensor  1510  can include a first sensor configured to detect the presence of a source tray and a second sensor configured to detect the presence of a process tray. 
     The CPU  1520  is configured to control and receive input from the sensor  1510 , the memory  1530 , and the actuators  1540 ,  1550 ,  1560 ,  1570 ,  1580 ,  1590 . The memory  1530  can store data received from the CPU  1520  and send data stored therein to the CPU  1520 . Examples of information that may be received and stored in the memory  1530  include, for example, information received at the CPU  1520  from the sensor  1510 , information received at the CPU from the actuators  1540 ,  1550 ,  1560 ,  1570 ,  1580 ,  1590 , and one or more computer-executable instructions that, when executed by the CPU  1520 , cause the CPU to selectively activate and/or deactivate the actuators  1540 ,  1550 ,  1560 ,  1570 ,  1580 ,  1590  in a predetermined sequence to transfer items from a source tray to a process tray. 
     The actuators  1540 ,  1550 ,  1560 ,  1570 ,  1580 ,  1590  can be electronically controllable actuators each coupled to and configured to move one or more mechanical components of the system  1500 . Each actuator  1540 ,  1550 ,  1560 ,  1570 ,  1580 ,  1590  can include one or more electric motors, hydraulic cylinders, pneumatic actuators, screw jacks, servos, solenoids, or the like. In the exemplary tray content transfer system  200  depicted in  FIGS.  2 A- 2 D , the actuators may be arranged such that actuator  1   1540  is configured to move the end pushers  226  inward and outward to secure and release a source tray  280 , actuator  2   1550  is configured to move the process tray clamps  228  inward and outward to secure and release a process tray  290 , actuator  3   1560  is configured to move the vertical sliders  252  up and down the vertical tracks  216  to rotate the rotation frame  220  between upright and rotated orientations, actuator  4   1570  is configured to slide the horizontal translation platform  232  along axis  233  on the horizontal track member  234 , actuator  5   1580  is configured to slide the vertical translation platform  236  along axis  237  on the vertical track members  238 , and actuator  6   1590  is configured to slide the paddle slider  246  along axis  247  on the paddle assembly track member  248 . 
       FIG.  16    is a flowchart illustrating an exemplary method  1600  of initiating the transfer of items from a container. The method  1600  can be performed by a computer system integrated within a system such as the tray content transfer system  1500  depicted in  FIGS.  2 A- 15   . 
     The method  1600  begins with block  1610 , where the system  1500  begins receiving information from the sensor  1510 . The information can be an electrical signal indicating that a source tray and/or a process tray have or have not been detected within the system  1500 . When the system  1500  has begun receiving information from the sensor  1510 , the method  1600  continues to decision state  1620 . 
     At decision state  1620 , the method  1600  determines whether a source tray has been detected. For example, the CPU  1520  can analyze a signal received from the sensor  1510  configured to detect the presence of a source tray within the system  1500  at a suitable location for transferring items from the source tray. If the method  1600  determines that a source tray has not been detected, the method  1600  continues to block  1625 , where the method  1600  waits for a source tray to be detected and returns to decision state  1620 . If the method  1600  determines that a source tray has been detected, the method continues to decision state  1630 . 
     At decision state  1630 , the method  1600  determines whether a process tray has been detected. For example, the CPU  1520  can analyze a signal received from the sensor  1510  configured to detect the presence of a process tray within the system  1500  at a suitable location for receiving items transferred from the source tray. If the method  1600  determines that a process tray has not been detected, the method  1600  continues to block  1635 , where the method  1600  waits for a process tray to be detected and returns to decision state  1630 . If the method  1600  determines that a process tray has been detected, the method  1600  continues to block  1640 . At block  1640 , the method  1600  terminates by initiating the transfer of items from the source tray to the process tray. 
       FIG.  17    is a flowchart illustrating an exemplary method  1700  of transferring items from a source tray to a process tray in a tray content transfer system. The method  1700  can be initiated at block  1640  of the method  1600  depicted in  FIG.  1600   . The method  1700  can be performed by a computer integrated within a tray content transfer system such as the systems  200  and  1500  depicted in  FIGS.  2 A- 15   . 
     The method  1700  begins at block  1710 , where the source tray  280  and process tray  290  are secured within the tray content transfer system  200 ,  1500 . Securing the source tray  280  and the process tray  290  can include moving the end pushers  226  and the process tray clamps  228  inward to secure the source tray  280  and the process tray  290  to the horizontal sub-frame  222 . The end pushers  226  and process tray clamps  228  can be moved inward by actuators such as actuator  1   1540  and actuator  2   1550  based on instructions provided by the CPU  1520 . After the source tray  280  and the process tray  290  are secured within the system  200 ,  1500 , the method  1700  continues to block  1720 . 
     At block  1720 , the items  205  within the source tray  280  are secured. For example, the items  205  can be secured by moving one or both of the paddles  242  inward, such as by moving the paddle slider  246  along axis  247  on the paddle assembly track member  247  to move the paddles  242  closer together and engage the items  250  between the paddles  242 . The paddles  242  can be moved by actuators such as actuator  6   1590  based on instructions provided by the CPU  1520 . After the items  205  within the source tray  280  are secured, the method  1700  continues to block  1730 . 
     At block  1730 , the rotation frame  220  is rotated to a rotated orientation. For example, the rotation frame  220  can be rotated by moving vertical sliders  252  up the vertical tracks  216  such that the rotation frame  220  rotates about the hinges  250  by an angle of approximately 90° or more, and the items  205  are at least partially supported by the back plates  245  of the paddle assembly  240 . The rotation frame  220  can be rotated by actuators such as actuator  3   1560  based on instructions provided by the CPU  1520 . After the rotation frame  220  is rotated to a rotated orientation, the method  1700  continues to block  1740 . 
     At block  1740 , the items  205  are moved from the source tray  280  to the process tray  290 . For example, the items  205  can be moved from the source tray  280  to the process tray  290  by first, sliding the vertical translation platform  236  away from the source tray  280  along axis  237  on the vertical track members  238 , second, sliding the horizontal translation platform  232  along axis  233  on the horizontal track member  234  such that the paddle assembly  240  containing items  205  is positioned near or adjacent to the process tray  290 , and third, sliding the vertical translation platform  236  toward the process tray  280  along axis  237  on the vertical track members  238  such that the paddle assembly  240  and items  205  are at least partially within the process tray  290 . The horizontal translation platform  232  and the vertical translation platform  236  can be moved by actuators such as actuator  4   1570  and actuator  5   1580 , based on instructions provided by the CPU  1520 . After the items  205  are moved from the source tray  280  to the process tray  290 , the method  1700  continues to block  1750 . 
     At block  1750 , the rotation frame  220  is rotated to an upright orientation. For example, the rotation frame  220  can be rotated by moving vertical sliders  252  back down the vertical tracks  216  such that the rotation frame  220  rotates about the hinges  250  by the same angle of rotation as in block  1730 . After the rotation frame  220  is rotated back to an upright orientation, some or all of the items  205  may remain suspended above the process tray  290  by the paddles  242 , and/or some or all of the items  205  may begin to fall into the process tray, depending on the clasping force exerted against the items  205  by the paddles  242 . The rotation frame  220  can be rotated by actuators such as actuator  3   1560  based on instructions provided by the CPU  1520 . After the rotation frame  220  is rotated to an upright orientation, the method  1700  continues to block  1760 . 
     At block  1760 , the items  205  are released into the process tray  290 . For example, the items  205  can be released by moving one or both of the paddles  242  outward, such as by moving the paddle slider  246  along axis  247  on the paddle assembly track member  247  to move the paddles  242  further apart and cease to clasp the items  250  between the paddles  242 . The paddles  242  can be moved by actuators such as actuator  6   1590  based on instructions provided by the CPU  1520 . After the items  205  are released into the process tray, the method  1700  continues to block  1770 . 
     The method  1700  terminates at block  1770 , where the source tray  280  and process tray  290  are released within the tray content transfer system  200 ,  1500 . Releasing the source tray  280  and the process tray  290  can include moving the end pushers  226  and the process tray clamps  228  outward to release the source tray  280  and the process tray  290  from the horizontal sub-frame  222 . The end pushers  226  and process tray clamps  228  can be moved outward by actuators such as actuator  1   1540  and actuator  2   1550  based on instructions provided by the CPU  1520 . After the source tray  280  and the process tray  290  are released from the system  200 ,  1500 , the method  1700  terminates. The source tray  280  and the process tray  290  can be removed from the system manually or by one or more automated systems. 
       FIG.  18    is a front perspective view of a tray content transfer system  1800  in accordance with an exemplary embodiment. The tray content transfer system  1800  generally includes a frame  1810 , an item platform  1830 , a source tray platform  1840 , a process tray platform  1850 , and a pedal  1820  mechanically coupled to two pushers  1822 . 
     The frame  1810  is generally configured to provide a stable support for the item platform  1830 , the source tray platform  1840 , the process tray platform  1850 , and the pedal  1820 . The frame  1810  includes various structural members  1812  and two vertical tracks  1816 . As will be described with reference to the pedal  1820 , the vertical tracks  1816  are configured to accommodate and/or at least partially actuate vertical movement of the pushers  1822 . In various embodiments, the frame  1810  can be any size, shape, or configuration suitable to support the item platform  1830 , the source tray platform  1840 , the process tray platform  1850 , and the pedal  1820 . For example, the frame  1810  can be built into a wall, a shelf, a floor, or the like, and need not be a free-standing rectangular frame as shown in the figures. 
     The process tray platform  1850  is a generally rigid horizontal surface including two slots  1852 . In various embodiments, at least a portion of the process tray platform  1850  can be a solid, flat surface, and/or can include a textured surface, a grating, a mesh, a plurality of longitudinal members, or the like. The slots  1852  are sized, shaped, and located within the process tray platform so as to allow at least a portion of each of the pushers  1822  to extend through the slots  1852 . For example, the slots  1852  can have dimensions at least as large as cross-sectional dimensions of the pushers  1822  such that the pushers  1822  can pass through the slots  1852  without obstruction, friction, undue wear and tear, etc. As shown in  FIGS.  19 - 22   , the process tray platform  1850  has a length and width selected to accommodate a process tray  1890  resting thereon. 
     The source tray platform  1840  is a shelf located in proximity to the process tray platform  1850 . In various embodiments, the source tray platform  1840  can be located at any side proximate the process tray platform  1850 . The source tray platform can include a generally rigid material and/or can be at least partially formed from a textured surface, a grating, a mesh, or the like. As shown in  FIGS.  19 - 22   , the source tray platform  1840  is sized and shaped to receive a source tray  1880 . 
     The item platform  1830  is a shelf located at a second location proximate the process tray platform  1850 . The item platform  1830  includes a bottom surface  1832 , a rear surface  1834 , and a transition segment  1836 . The item platform  1830  can include a generally rigid material, and/or can be at least partially formed from a textured surface, a grating, a mesh, or the like. In some embodiments, the bottom surface  1832  is slanted backward toward the rear surface  1834 , such that items on the item platform  1830  rest against the bottom surface  1832  and the rear surface  1834 , and are thereby prevented from falling off of the item platform  1830 . The transition segment  1836  is a generally flat surface, such as a ramp or slope, contiguous with the bottom surface  1832 . The transition segment  1836  is sloped in two dimensions. The transition segment  1836  is generally sloped downward from the item platform  1830  toward the process tray platform  1850 , and further has a transverse frontward slope component to transition from the backward slant of the bottom surface  1832  to a level profile at the end of the transition segment  1836  adjacent to the process tray platform  1850 . As shown in  FIGS.  19 - 22   , the item platform  1830  is configured to receive items  1805  that are not in a source tray  1880 , and to accommodate sliding of the items along the bottom surface  1832  and transition segment  1836  into a process tray  1890 . 
     The pedal  1820  is a foot operable pedal disposed in a lower portion of the tray content transfer system  1800 . The pedal  1820  can be disposed at least partially within the boundaries of the frame  1810 , in a location where it can be accessed and actuated by an operator. The pedal  1820  is mechanically coupled to the pushers  1822 , such that depressing the pedal  1820  causes the pushers  1822  to travel upward along the vertical tracks  1816  and extend at least partially through the slots  1852 . Similarly, releasing the pedal upward from a depressed position causes the pushers  1822  to travel downward along the vertical tracks  1816  so that the ends of the pushers  1822  do not extend beyond the surface of the process tray platform  1850 . The operation of the pedal  1822  will be described below with reference to  FIGS.  19 - 22   . 
       FIGS.  19 - 22    sequentially illustrate an example process for transferring the contents of a source tray  1880  to a process tray  290 . Although the process of  FIGS.  19 - 22    is shown and described in the context of the tray content transfer system  1800  depicted in  FIG.  18   , it will be appreciated that the same or similar steps may be implemented in any other tray content transfer system. The process of  FIGS.  19 - 22    can be performed at least partially manually and/or automatically, for example, by a computer system integrated within a system such as the tray content transfer system  1800  depicted in  FIG.  18   . 
       FIG.  19    depicts an initial state of the tray content transfer system  1800  for a transfer process. In the initial state, the items  1805  can be contained within the source tray  1880  and/or on the item platform  1830 . The items can be, for example, letters, flats, etc. In the initial state of  FIG.  19   , the process tray  1890  has been placed onto the process tray platform  1850 . The process tray  1890  includes a movable inner surface  1892  and may further include a divider  1894 . The source tray  1880  has been placed onto the source tray platform  1840  so that it sits at an angle relative to the process tray  1890 . Alternatively or in addition to placing the source tray  1880  onto the source tray platform  1840 , items  1805  can be placed onto the item platform  1830 . For example, loose items  1805  may not be received in a source tray  1880 , and/or an operator of the tray content transfer system  1800  may prefer to transfer items from a source tray  1880  to the item platform  1830  rather than place the entire source tray  1880  onto the source tray platform  1840 . 
     After the process tray  1890  has been placed onto the process tray platform  1850  and the items  1805  have been placed into the system  1800  by placing the items  1805  onto the item platform  1830  and/or placing the source tray  1880  onto the source tray platform  1840 , the process continues to the configuration shown in  FIG.  20   . As shown in  FIG.  20   , the pedal  1820  travels to a depressed position (e.g., by being pushed downward by a foot of an operator). As the pedal  1820  is depressed, the pushers  1822  travel upward along the vertical tracks  1816 . As the pushers  1822  extend through the slots  1852  (not visible in  FIG.  20   ), the upper ends of the pushers  1822  push the inner surface  1892  upward such that the inner surface  1892  is at a similar height to the surface of the item shelf  1830  at the end of the transition segment  1836 . For example, the inner surface  1892  of the process tray  1890  may be raised relative to the rigid sides of the process tray  1890 , as shown in  FIG.  20    to facilitate the transfer of the items  1805  into the process tray  1890 . In some embodiments, the system  1800  can include one or more motors configured to raise the pushers  1822  and/or depress the pedal  1820  responsive to an operator input and/or automatically based on detection of a process tray  1890  on the process tray platform  1850 . 
     Referring now to  FIG.  21   , after the pedal  1820  is depressed to raise the inner surface  1892  of the process tray  1890 , the items  1805  are moved into the process tray  1890 . The items  1805  that were contained in the source tray  1880  can be manually moved horizontally and/or vertically out of the source tray  1880  and placed onto the inner surface  1892 . In this case, the elevated position of the inner surface  1892  can facilitate the transfer of the items  1805  from the source tray  1880  to the process tray  1890 , by decreasing the vertical distance the items  1805  must be moved manually or mechanically (e.g., by grippers or other mechanical movers as depicted in the other figures), reducing the probability of dropping the items  1805  during the transfer. 
     The items  1805  that were located on the item platform  1830  can slide along the bottom surface  1832  and the transition segment  1836  onto the inner surface  1892  of the process tray  1890 . In this case, the elevated position of the inner surface  1892  can allow the items  1805  to slide from the item platform  1830  into the process tray  1890  at substantially the same or similar height, such that the items  1805  do not need to be picked up and thereby reducing the probability of dropping the items  1805  during the transfer. In some embodiments, the sliding of the items  1805  along the item platform  1830  can be performed automatically, such as by one or more paddles or other item moving members sliding the items  1805 . 
     Referring now to  FIG.  22   , after the items  1805  are moved into the process tray  1890 , the pedal  1820  is released and moves upward to its original position. As the pedal  1820  is released, the pushers  1822  travel downward along the vertical tracks  1816 . When the pushers  1822  travel downward, the inner surface  1892  of the process tray  1890  is allowed to travel downward to rest within the process tray  1890 . The system  1800  is thus in its original position, and the source tray  1880  and process tray  1890  can be removed. In some embodiments, the pushers  1822  can be moved downward by one or more motors, responsive to an operator input or other indication that the items  1805  have been transferred. The tray content transfer process can be repeated indefinitely as additional source trays  1880  and/or items  1805  arrive with contents to be transferred. 
       FIG.  23 A  is a front perspective view of a tray content transfer system  2300  in accordance with an exemplary embodiment. The tray content transfer system  2300  generally includes a frame  2310 , an item platform  2330 , a source tray platform  2340 , and a process tray platform  2350 . 
     The frame  2310  is generally configured to provide a stable support for the item platform  2330 , the source tray platform  2340 , and the process tray platform  2350 . The frame  2310  includes various structural members  2312  connected to form a stable structure. In various embodiments, the frame  2310  can be any size, shape, or configuration suitable to support the item platform  2330 , the source tray platform  2340 , and the process tray platform  2350 . For example, the frame  2310  can be built into a wall, a shelf, a floor, or the like, and need not be a free-standing rectangular frame as shown in the figures. 
     The process tray platform  2350  is a generally rigid horizontal surface sized to accommodate a process tray. In various embodiments, at least a portion of the process tray platform  2350  can be a solid, flat surface, and/or can include a textured surface, a grating, a mesh, a plurality of longitudinal members, or the like. As shown in  FIGS.  24 - 27   , the process tray platform  2350  has a length and width selected to accommodate a process tray  2390  resting thereon. 
     The item platform  2330  is a shelf located at a second location proximate the process tray platform  2350 . The item platform  2330  includes a bottom surface  2332  and a rear surface  2334 . The item platform  2330  can include a generally rigid material, and/or can be at least partially formed from a textured surface, a grating, a mesh, or the like. In some embodiments, the bottom surface  2332  can be generally flat, or can be slanted backward toward the rear surface  2332  (e.g., with a transition segment provided similar to the transition segment  1836  depicted in  FIG.  18   ). As shown in  FIGS.  24 - 27   , the item platform  2330  is configured to receive items  2305  that are not in a source tray  2380 , and to accommodate sliding of the items  2305  along the bottom surface  2332  into a process tray  2390 . Accordingly, the height of the bottom surface  2332  relative to the height of the process tray platform  2350  may be selected based on the thickness of the bottom of a process tray  2390  to be used with the tray content transfer system  2300 . For example, if the height difference between the bottom surface  2332  and the process tray platform  2350  is equal to the thickness of the bottom of the process tray, an inner surface of the process tray on the process tray platform  2350  will be at the same height as the bottom surface  2332  so as to facilitate the sliding of items from the item platform  2330  into the process tray. 
       FIG.  23 B  depicts an example process tray  2390  configured for use with the tray content transfer system  2300  depicted in  FIG.  23 A . The process tray  2390  includes an inner surface  2392 , a movable divider  2394 , a removable end wall  2396 , and side walls  2398 . The inner surface  2392  and the side walls  2398  generally support and contain items within the process tray  2390 . The end wall  2396  can be removed by sliding the end wall  2396  out of the process tray  2390  along the direction indicated by arrow  2397 . For example, the end wall  2396  may be removed to allow items to be transferred into the process tray  2390  by sliding. After the items slide onto the inner surface  2392 , the end wall  2396  may be replaced by moving in a direction opposite arrow  2397 . Similarly, the divider  2394  may be removed from the process tray  2390  by sliding the divider  2394  along the direction indicated by arrow  2395 . The divider  2394  may be reinserted at a different location along the inner surface  2392 , for example, based on the amount of space required to accommodate items that will be placed into the process tray  2390 . 
       FIG.  24    depicts an initial state of the tray content transfer system  2300  for a transfer process. In the initial state, the items  2305  can be contained within the source tray  2380  and/or on the item platform  2330 . The items can be, for example, letters, flats, etc. In the initial state of  FIG.  24   , the process tray  2390  has been placed onto the process tray platform  2350 . The divider  2394  has been positioned at an intermediate location along the inner surface  2392  of the process tray  2390 , for example, based on the number and/or volume of items  2305  to be transferred. The source tray  2380  has been placed onto the source tray platform  2340  so that it sits at an angle relative to the process tray  2390 . Alternatively or in addition to placing the source tray  2380  onto the source tray platform  2340 , items  2305  can be placed onto the item platform  2330 . For example, loose items  2305  may not be received in a source tray  2380 , and/or an operator of the tray content transfer system  2300  may prefer to transfer items from a source tray  2380  to the item platform  2330  rather than place the entire source tray  2380  onto the source tray platform  2340 . 
     After the process tray  2390  has been placed onto the process tray platform  2350  and the items  2305  have been placed into the system  2300  by placing the items  2305  onto the item platform  2330  and/or placing the source tray  2380  onto the source tray platform  2340 , the process continues to the configuration shown in  FIG.  25   . As shown in  FIG.  25   , the removable end wall  2396  has been lifted out of the process tray  2390  to enable the sliding of items  2305  from the item platform  2330  into the process tray  2390 . In the exemplary embodiment depicted, the bottom surface  2332  of the item platform is at approximately the same height as the inner surface  2392  of the process tray  2390 . 
     After the removable end wall  2396  has been lifted out of the process tray  2390 , the process continues to the configuration shown in  FIG.  26   . As shown in  FIG.  26   , the items  2305  have been placed into the process tray  2390 . The items  2305  previously located on the item platform  2330  have been transferred along the bottom surface  2332  of the item platform  2330  into the process tray  2390 . The items  2305  previously located within the source tray  2380  have been lifted out of the source tray  2380  and lowered into the process tray  2390 . In implementations in which items  2305  are only being transferred from a source tray  2380  and not from the item platform  2330 , it will be appreciated that the end wall  2396  of the process tray  2390  need not be lifted to facilitate the transfer of items  2305 . 
     Referring now to  FIG.  27   , after the items  2305  are moved into the process tray  2390 , the end wall  2396  is lowered to the position depicted in  FIG.  27   . The process tray  2390  is thus in its original configuration and contains the items  2305  therein. The process tray  2390  can thus be removed from the system  2300  for further processing or transport of the items  2305 . The tray content transfer process depicted in  FIGS.  24 - 27    can be repeated indefinitely as additional source trays  2380  and/or items  2305  arrive with contents to be transferred. 
     The foregoing description details certain embodiments of the systems, devices, and methods disclosed herein. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the systems, devices, and methods can be practiced in many ways. It should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the technology with which that terminology is associated. 
     It will be appreciated by those skilled in the art that various modifications and changes may be made without departing from the scope of the described technology. Such modifications and changes are intended to fall within the scope of the embodiments. It will also be appreciated by those of skill in the art that parts included in one embodiment are interchangeable with other embodiments; one or more parts from a depicted embodiment can be included with other depicted embodiments in any combination. For example, any of the various components described herein and/or depicted in the Figures may be combined, interchanged or excluded from other embodiments. 
     With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     It will be understood by those within the art that, in general, terms used herein are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” 
     All references cited herein are incorporated herein by reference in their entirety. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material. 
     The term “comprising” as used herein is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. 
     It is noted that some examples above may be described as a process, which is depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel, or concurrently, and the process can be repeated. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a software function, its termination corresponds to a return of the function to the calling function or the main function. 
     The above description discloses several methods and materials of the present invention. This invention is susceptible to modifications in the methods and materials, as well as alterations in the fabrication methods and equipment. Such modifications will become apparent to those skilled in the art from a consideration of this disclosure or practice of the invention disclosed herein. Consequently, it is not intended that this invention be limited to the specific embodiments disclosed herein, but that it cover all modifications and alternatives coming within the true scope and spirit of the invention as embodied in the attached claims.