As / rs lift with vertically aligned dual carriages

Abstract

A material handling system has a vertical lift having two vertically aligned carriages that are independently positionable on a vertical support structure by respective drive systems. A processor subsystem selects one of the two carriages to move a good from at least one infeed conveyor to a selected level of an automated storage and retrieval system (AS / RS). The processor subsystem simultaneously positions the other carriage to avoid a collision.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to the material handling of containers, packages, and discrete goods, and more particularly to techniques for moving products into and out of an automated storage and retrieval system (AS / RS) using vertical lifts. BACKGROUND

[0002] To reduce the cost of storing large inventories, retailers and distributors are increasingly relying on systems that can quickly receive wholesale quantities of specific goods and create subsets of different goods as consumer or store replenishment orders. In some cases, selections can be made from a large number of possible types of goods to complete a particular order. Automation allows the selected goods to be transported from a receiving location, sorted into order containers as needed, and the completed order containers transported to a shipping location. Generally, some human interaction is needed along some portions of other automated material handling systems.

[0003] AS / RS systems are designed for the automated storage and retrieval of parts and items in manufacturing, distribution, retail, wholesale, and institutional settings. They originated in the 1960s, initially focusing on heavy pallet loads, but as technology has advanced, the loads being handled have become smaller. The system operates under computerized control, maintaining an inventory of stored items. Retrieval of an item is accomplished by specifying the type and quantity of items to be retrieved. The computer determines the location in the storage area where the items can be retrieved and schedules the retrieval. It directs the appropriate automated storage and retrieval machine (SRM) to the location where the items are stored and directs the machine to deposit the items at the location where it will be picked up. A system of conveyors and or automated guided vehicles, such as shuttles, are sometimes part of the AS / RS system. These move the loads into and out of the storage area and move them to manufacturing floors, loading docks, palletizers, or order fulfillment stations. To store an item, a pallet or bin is placed at an input station, inventory information is entered into a computer terminal, and the AS / RS system moves the load to the storage area, determines the appropriate location for the item, and stores the load. As items are stored into or retrieved from racks, the computer updates its inventory accordingly.

[0004] Benefits of AS / RS systems include reduced labor to transport items into and out of inventory, reduced inventory levels, more accurate tracking of inventory, and space savings. Items are typically stored more densely than in systems where items are stored and retrieved manually. The trend toward just-in-time production often requires production input, mixed pallet output, or sub-pallet level availability for e-commerce order fulfillment, and AS / RS is a much faster way to organize storage of smaller items next to the production line.

[0005] One AS / RS technology is known as the shuttle technology. In this technology, horizontal movement is performed by independent shuttles that each operate on a level of a rack, while elevators at fixed locations within the rack are responsible for vertical movement. By using two separate machines for these two axes, the shuttle technology can provide higher throughput than stacker cranes and multi-level shuttles. The storage and retrieval machines pick up or drop off loads to the supports of the support transport system at specific stations, where the loads that are inbound and outbound are precisely positioned for proper handling.

[0006] Typically, vertical elevators can be a limiting item for the overall throughput of an AS / RS system. Each vertical elevator is also a significant portion of the cost of the overall AS / RS solution. Adding additional vertical elevators can make the resulting solution too expensive and the return on investment insufficient to justify. SUMMARY

[0007] The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed aspects. This summary is not an extensive overview, and is neither intended to identify key or critical elements nor to delineate the scope of such aspects. Its purpose is to present some concepts of the described features in a simplified form as a prelude to the more detailed description that is presented later.

[0008] In accordance with one or more aspects and corresponding disclosure thereof, various aspects are described in connection with a material handling system that includes a storage rack having more than one vertically spaced level. Each level has a plurality of storage locations accessible from an adjacent aisle. One or more shuttle vehicles serve respective levels of the storage rack. A vertical elevator has a vertical support structure positioned proximate the storage rack. The vertical support structure has first and second carriages that are independently positionable along respective and first and second vertical portions of the vertical support structure. A first vertical drive system is coupled to the first carriage to position the first carriage to pick up and deposit items at a selected level within the first vertical portion of the vertical support structure. A second vertical drive system is coupled to the second carriage to position the second carriage to pick up and deposit items at a selected level within the second vertical portion of the vertical support structure. A processor subsystem is in communication with the first and second vertical drive systems to selectively position the first and second carriages at respective selected levels without colliding with each other.

[0009] According to one or more aspects and corresponding disclosure thereof, various aspects are described in connection with a vertical lift including a vertical support structure positionable proximate to a storage rack. A first and second carriage are housed for vertical movement along the vertical support structure. Each of the first and second carriages are independently positionable on the vertical support structure in first and second vertical portions of the vertical support structure, respectively. A first vertical drive system is coupled to the first carriage to position the first carriage to pick and put away items at a selected level within the first vertical portion of the vertical support structure. The selected level corresponds to a level of the storage rack. The level has a plurality of storage locations accessible from an adjacent aisle, the plurality of storage locations serviced by one or more shuttle vehicles. A second vertical drive system is coupled to the second carriage to position the second carriage to pick and put away items at a selected level within the second vertical portion of the vertical support structure. The selected level corresponds to a level of the storage rack. The level has a plurality of storage locations accessible from an adjacent aisle, the plurality of storage locations serviced by one or more shuttle vehicles. A processor subsystem is in communication with the first and second vertical drive systems to selectively position the first and second carriages at respective selected levels without colliding with each other.

[0010] According to one or more aspects and corresponding disclosure thereof, various aspects are described in connection with a method of moving items into and out of an AS / RS using a vertical lift having two vertically aligned carriages. The method includes conveying items on an inbound conveyor to a storage rack having more than one vertically spaced level, each level having a plurality of storage locations accessible from an adjacent aisle. The method includes receiving a selected storage location for an item. The method includes selecting one carriage of a vertical lift to receive the product from the inbound conveyor based at least in part on a corresponding level of the storage rack associated with the selected storage location. The vertical lift has a vertical support structure positioned proximate to the storage rack. The one carriage is vertically aligned with another carriage of the vertical lift. The carriages are independently positionable along respective first and second vertical portions of the vertical support structure. The method includes activating one vertical drive system to position the one carriage at the inbound conveyor. The method includes receiving the item on the one carriage. The method includes activating the one vertical drive system to position the one carriage at the corresponding level to put away the item for pick up by a shuttle vehicle servicing the adjacent aisle. The method includes activating another vertical drive system to position the other carriage to avoid any collision with the one carriage during movement to receive and put away the item.

[0011] For implementing the foregoing and related advantages, one or more aspects include the features as fully described below and particularly pointed out in the claims. The following description and drawings set forth certain illustrative aspects and are indicative of the various ways in which the principles of these aspects can be employed. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings and the disclosed aspects are intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF DRAWINGS

[0012] The features, nature, and advantages of the present disclosure will become more apparent from the detailed description set forth below when considered in conjunction with the drawings and the disclosed aspects are intended to include all such aspects and their equivalents.

[0013] Figure 1 FIG. illustrates a perspective view of a material handling system including an automated storage and retrieval system (AS / RS) utilizing a dual carriage lift, in accordance with one or more embodiments;

[0014] Figure 2 FIG. illustrates an isometric view of an exemplary dual carriage lift of the material handling system of Figure 1 FIG. illustrates an isometric view of an exemplary dual carriage lift of the material handling system of

[0015] Figure 3 FIG. illustrates an isometric detail view of one carriage of the dual carriage lift of Figure 2 FIG. illustrates an isometric detail view of one carriage of the dual carriage lift of

[0016] Figure 4 FIG. illustrates an isometric detail view of a dual vertical drive system of the dual carriage lift of Figure 2 FIG. illustrates an isometric detail view of a dual vertical drive system of the dual carriage lift of

[0017] Figure 5 FIG. illustrates a perspective view of a single layer shuttle (OLS) vehicle serving one aisle of the AS / RS of Figure 1 FIG. illustrates a perspective view of a single layer shuttle (OLS) vehicle serving one aisle of the AS / RS of

[0018] Figure 6 FIG. illustrates a functional block diagram of an exemplary material handling control system, in accordance with one or more embodiments;

[0019] Figure 7 FIG. illustrates a functional block diagram of an exemplary material handling system having an exemplary AS / RS controller having a distributed architecture, in accordance with one or more embodiments;

[0020] Figure 8FIG. illustrates a side view of a first version of an AS / RS according to one or more embodiments, the first version of the AS / RS served by dual-cartridge lifts with overlapping vertical travel segments and infeed and outfeed conveyors, the infeed and outfeed conveyors individually served by one cartridge each;

[0021] Figure 9 FIG. illustrates a side view of a second version of an AS / RS according to one or more embodiments, the second version of the AS / RS served by dual-cartridge lifts with large overlapping vertical travel segments and infeed and outfeed conveyors, the infeed and outfeed conveyors served by either cartridge;

[0022] Figure 10 FIG. illustrates a side view of a third version of an AS / RS according to one or more embodiments, the third version of the AS / RS served by dual-cartridge lifts with non-overlapping vertical travel segments and infeed and outfeed conveyors, the infeed and outfeed conveyors individually served by one cartridge each;

[0023] Figure 11 FIG. illustrates a side view of a fourth version of an AS / RS according to one or more embodiments, the fourth version of the AS / RS served by dual-cartridge lifts with small overlapping vertical travel segments and infeed and outfeed conveyors, the infeed and outfeed conveyors individually served by one cartridge each; and

[0024] Figure 12 FIG. illustrates a flowchart of a method of increasing the throughput into and out of an AS / RS using dual-cartridge lifts according to one or more embodiments. DETAILED DESCRIPTION

[0025] Various aspects are now described with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. It can be evident, however, that various aspects can be practiced without some or all of these specific details. In other instances, well known structures and devices are shown in block diagram form in order to facilitate describing these aspects.

[0026] Figure 1An item handling system 100 is illustrated that includes an automated storage and retrieval system (AS / RS) 102. Storage racks 104 of the AS / RS 102 are provided with items for storage via an infeed conveyor 106. Items are taken away from the storage racks 104 by an outfeed conveyor 108 for order fulfillment, store replenishment, shipping, and the like. A dual-carriage vertical lift 110 moves items between the infeed and outfeed conveyors 104, 106 to appropriate levels of the storage racks 104. The vertical lift 110 has a vertical support structure 112 positioned proximate the storage racks 104 to pick and deposit items at selected levels 114 within the storage racks 104.

[0027] Figure 2 The vertical lift 110 is illustrated with first and second carriages 116, 118 vertically aligned that are independently positionable along respective first and second vertical portions 120, 122 of the vertical support structure 112. A first vertical drive system 124 is coupled to the first carriage 116 to position the first carriage 116 within the first vertical portion 120 of the vertical support structure 112. A second vertical drive system 126 is coupled to the second carriage 118 to position the second carriage 118 within the second vertical portion 122 of the vertical support structure 112. In an exemplary embodiment, each vertical drive system includes a drive belt 128, 130 housed at a front side 132 of the vertical support structure 112, laterally offset from one another and vertically aligned. The drive belts 128, 130 are housed over passive coaxial top pulleys 134, 136 and over independently driven coaxial bottom pulleys 140, 142, respectively, for vertical rotation. Figures 2-3 First and second drive motors 144, 146 of the first and second drive systems 124, 126 are illustrated as independently rotating the bottom pulleys 140, 142, respectively, through 90° reduction gear drives 148, 150.

[0028] Figure 4 The first carriage 116 is illustrated in two motor drive rollers (MDRs) 152, 154 that extend through a roller carriage 156 to a mounting bracket 158. Each MDR 152, 154 is an o-segment coupled to a subset of non-powered rollers 160 to form a live roller conveyor 162 for moving items onto and off of the vertical lift 110. Figure 2 Power can be provided to the carriages through a power bus, cable, or the like.

[0029] Figure 5The illustrated AS / RS 102 can include autonomous shuttle vehicles 164 that service storage locations 166 along one or more aisles 168 within the storage racks 104. The dual-tote vertical lift 110 ( Figure 2 ) leaves one / more items 170 at pick and drop (P / D) stations 172 on assigned levels 114 and aisles 168 of the storage racks 104. The shuttle vehicles 164 pick up one / more items 170 at the P / D stations 172, move them to assigned storage locations 166, and deposit the items 166 for storage. When needed, the shuttle vehicles 164 retrieve one / more items 170 from the assigned storage locations 166 and move them to the P / D stations 172 for pick up by the dual-tote vertical lift 110 ( Figure 2 ).

[0030] In Figure 6 , an exemplary material handling system 600 of a distribution center processing architecture 602 is depicted in which a dual-tote lift controller 604 is implemented within an AS / RS controller 606. Controller logic 608 stored within a computer-readable shared memory 610 is executed by a processor 612 in a controller 614 of the material handling system 600. One function of the controller logic 608 can be machine control logic. The controller 614 can be a master controller supported by a backup controller 615 so that maintenance personnel can swap cables or connections without undue service downtime in the event of a failure. Alternatively, in the event of a failure, a supervisory system or self-diagnostic function can cause an automatic switchover between the master and backup devices.

[0031] Scan logic (or just scan 616) refers to an implementation within the controller logic 608 in which the processor 612 repeatedly executes a read input component 618, a solve logic component 620, and a write output component 622. By performing this sequence periodically, cyclically (deterministically), then the machine control logic can count scans to measure time. The three steps can be performed by a programmable logic controller (PLC), a personal computer (PC), a small controller or microcontroller, etc. The solve logic component 620 can incorporate simple to complex, hardwired to configured, IF-THEN-ELSE branching logic, motion control. Data used by the solve logic component 620 can reside within the computer-readable shared memory 610 or a data storage device 624 (e.g., local, remote, cloud-based, etc.). A user interface 626 can be used to modify the solve logic component 620, for example, by changing values that cause a configuration or operation to change.

[0032] As conventionally understood, the controller logic 608 can receive binary type inputs (e.g., switches, photo eyes, etc.) and generate binary type outputs (e.g., motor contacts, solenoids, light actuation, etc.). For example, in such implementations, the user interface 626 can require at least in part push button controls and lights. Recent developments of the controller logic 608 can include RS232 serial devices with traditional cathode ray tube (CRT) screens and keyboards to implement dialog screens and data displays and printers for generating reports. More modern display types can also be supported, such as HDMI wired or wirelessly coupled flat screen displays. Bar code scanning can detect items being processed by the material handling system 600. Recently, wired and wireless communication within the material handling system 600 and distribution center processing architecture 602 has enabled more distributed and remotely isolated implementations. For example, such communication architectures can employ bus couplings such as PROFIBUS and ETHERCAT.

[0033] The scans 616 can be one of many control scans to support the increased speed and complexity of portions of the material handling system 600. Certain logic needs to be executed during shorter intervals than other logic and thus the scans 616 can have different periodicities, occurring for convenience generally selected as a multiple of the shortest duration scan 616. Examples include 1 ms and 2 ms scans 616 for motion control, 32 ms scans 616 for merge subsystems, and 211 ms scans 616 for general conveyors.

[0034] The host communication 628 can be incorporated into the host system 630 using serial ports, Ethernet, file transfer protocol (FTP), transmission control protocol / internet protocol (TCP / IP), etc. by the material handling system 600. Thus, the host system 630 can make decisions for the material handling system 600. For example, a scanner 632 can see a bar code. The bar code is sent to the host system 630, such as via the bridge 634. The host system 630 responds with a destination. In response, the material handling system 600 causes the item with the bar code to go to the destination. Alternatively, the process can require receiving a download of a batch of destinations or destinations for the material handling system 600 to reference, the destination being mapped to the bar code as part of a look up table (LUT).

[0035] The computer-readable shared memory 610 can enable execution of an operating system (e.g., Windows, Linux, etc.) 636 along with a real-time extension 638. The real-time extension 638 ensures that machine control logic (controller logic 608) begins execution exactly according to a desired schedule. Variations in the execution schedule are measured in microseconds. This approach ensures the kind of precision required for machine control while preserving opportunities for functionality and flexibility using a general-purpose operating system (e.g., Windows). A PLC that can also be included for machine control can operate in its own proprietary environment (hardware and software) and integrate using communications. Data 640 from these communications is stored in the computer-readable shared memory 610 for use in control decisions and for display on the user interface 626. In an exemplary version, the data 640 is not controlled by the real-time extension 638. In a similar manner, other communication devices 642 used in the control process (e.g., scales, printers) are connected to the processor 612 via a dedicated internal communication bus (e.g., Ethernet) 644. The controller 614 can also have internal input / output drivers 645 that interface using specific communication protocols.

[0036] The distribution center processing architecture 602 can include other systems external to the material handling system 600 that communicate via the bridge 634, such as a database 646, a warehouse control system (WCS) 648, and a warehouse management system (WMS) 650. Additionally or alternatively, a vertically integrated warehouse execution system (WES) 651 can combine automation layer control with order acquisition and fulfillment operations. Further, the user interface 626 can facilitate remote or automated interaction via user interfaces 626 depicted as local applications 652 and web applications 654. The controller 614 can include specific interfaces to support such interaction, such as a user interface data access component 656 for interacting with the user interface 626, middleware routing components 658 for interfacing with other external systems. Operating system services 660 and device communication components 662 can also support communications, such as sensors 664, actuators 667, diagnostic systems 668, and sorter speed controls 670.

[0037] The controller logic 608 can be functionally described as a material handling control layer 672 with software functionality such as sortation controls 673 that addresses certain subsystems within the distribution center: order fulfillment 674, carousel management 676, tilt tray / cross belt (TT / CB) controls 678, conveyor controls 680, order manager 682, and routing manager 684.

[0038] Figure 7A material handling system 700 is illustrated having an exemplary AS / RS controller 702 having a distributed architecture for controlling: (i) one or more multi-level shuttle (MLS) vehicles 704, (ii) one or more single-level shuttle (OLS) vehicles 706, (iii) infeed and outfeed conveyors 708, and (iv) independent vertical drive systems A and B 710, 712 of a dual-cartridge vertical lift 714. In one or more embodiments, the material handling system 100 includes a client enterprise resource planning (ERP) / host system 716 that manages orders and inventory and other functions that reside on a client backbone network 718 as part of an ERP / host layer control 720. A warehouse management system (WMS) / material flow system (MFS) control layer 722 manages warehouse specific functions between the ERP / host layer control 720 and an automation control layer 724 provided by the AS / RS controller 702. The WMS / MFS control layer 722 can include a computing environment operating on a logistics system local access network (LAN) 726, such as a virtual private network (VPN) connection 728, client workstations 730, and a WMS / MFS server system 732 that is also on the client backbone network 718.

[0039] The AS / RS controller 702 can include a multi-level shuttle control 734 that controls the MLS vehicles 704. In one embodiment, a programmable logic controller (PLC) 734 can manage the P / D conveyors and front end through a field bus conveyor front end network 736. MLS station cabinets 738 can include an aisle access control 740 that provides secure access for maintenance personnel to access the storage racks 104 Figure 1 A feed rail power supply 742 can energize power strips 744 that power the MLS vehicles 704. A data interface (I / F) 746 can wirelessly communicate with the MLS vehicles 704 to direct merchandise to and from assigned storage locations.

[0040] The AS / RS controller 702 can include an OLS control 748 for controlling the OLS vehicles 706. For example, a static aisle control 750 can include a PLC control 752 that interfaces with a field bus conveyor front end 754 and an aisle access control 756 for secure access by personnel to the storage racks 104 Figure 1 A feed rail power supply 758 can energize power strips 760 that power the OLS vehicles 706.

[0041] The AS / RS controller 702 can include an AS / RS lift controller 762 including a processor subsystem 764 (such as a PLC controller) that executes infeed, outfeed, and vertical lift controls 766. The processor subsystem 764 allocates dual-carriage 768, 770 movement without collision.

[0042] For one example, Figure 8 A first version 800 of an AS / RS served by a dual-carriage lift 802 employing overlap 804 in respective vertical travel segments 806, 808 of carriages 810, 812 is illustrated. An upper infeed and outfeed conveyor 814 is served by carriage 810 alone. A lower infeed and outfeed conveyor 818 is served by carriage 812 alone. Figure 9 A second version 900 of an AS / RS served by a dual-carriage lift 902 employing large overlap 904 in respective vertical travel segments 906, 908 of carriages 910, 912 is illustrated. An infeed and outfeed conveyor 914 aligned with the large overlap 904 is served by either carriage 910, 912. Figure 10 A third version 1000 of an AS / RS served by a dual-carriage lift 1002 employing non-overlapping segments 1104 between vertical travel segments 1006, 1008 is illustrated. An upper infeed and outfeed conveyor 1014 is served by carriage 1010 alone. A lower infeed and outfeed conveyor 1018 is served by carriage 1012 alone. Figure 11 A fourth version 1100 of an AS / RS served by a dual-carriage lift 1102 employing small overlap 1104 in respective vertical travel segments 1106, 1108 of carriages 1110, 1112 is illustrated. An upper infeed and outfeed conveyor 1114 is served by carriage 1110 alone. A lower infeed and outfeed conveyor 1118 is served by carriage 1112 alone.

[0043] In use, the method 1200 illustrates a method of increasing the throughput of goods into and out of an AS / RS storage rack using a single vertical lift. In one or more embodiments, the method 1200 includes conveying goods on an infeed conveyor to a storage rack having more than one vertically spaced tier, each tier having a plurality of storage locations accessible from an adjacent aisle (block 1202). The method 1200 includes receiving a selected storage location for a good (block 1204). The method 1200 includes selecting one carriage of a vertical lift to receive the product from the infeed conveyor based at least in part on a corresponding tier of the storage rack associated with the selected storage location. The vertical lift has a vertical support structure positioned proximate the storage rack. The one carriage is vertically aligned with another carriage of the vertical lift. Each carriage is independently positionable along respective first and second vertical portions of the vertical support structure (block 1206). The method 1200 includes activating one vertical drive system to position the one carriage at the infeed conveyor (block 1208). The method 1200 includes receiving the good on the one carriage (block 1210). The method 1200 includes activating the one vertical drive system to position the one carriage at the corresponding tier to deposit the good for retrieval by a shuttle vehicle servicing the adjacent aisle (block 1212). The method 1200 includes activating another vertical drive system to position the other carriage to avoid any collisions with the one carriage during movement to receive and deposit the good (block 1214). The method 1200 includes receiving a command to remove the good from the selected storage location (block 1216). The method 1200 includes selecting the one carriage to receive the good at the corresponding tier and deposit the good at an outfeed conveyor (block 1218). The method 1200 includes activating the corresponding vertical drive system to convey the good on the one carriage and simultaneously position the other carriage out of the way of the one carriage (block 1220).

[0044] While the present disclosure has been described with reference to example embodiments, it will be understood by those skilled in the art that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications can be made to adapt a particular system, device, or component thereof to the teachings of the present disclosure without departing from the central scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best currently contemplated mode of carrying out this present disclosure but that the disclosure will include all embodiments falling within the scope of the appended claims. Furthermore, the use of the terms "first", "second" and the like does not imply any order or importance, but is used for distinguishing one element from another.

[0045] According to various aspects of the disclosure, an element, any portion of an element, or any combination of elements can be implemented with a "processing system" that includes one or more physical devices configured to access instructions (for example, coded instructions) stored in a memory. The instructions are executable by a processor of the processing system. A "processor" includes, for example, a central processing unit (CPU), a graphics processing unit (GPU), a hardware logic circuit, a microprocessor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), another class of programmable logic device, a state machine, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system can execute the instructions. A processing system that executes instructions to achieve a result is a processing system configured to perform the task that results in the result, such as by providing one or more components of the processing system with instructions that will cause those components to perform actions that themselves or in combination with other actions performed by other components of the processing system will result in the outcome. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software can reside on a computer-readable medium. The computer-readable medium can be a non-transitory computer-readable medium. A computer-readable medium includes, for example, magnetic storage devices (for example, hard disk; floppy disk; magnetic strips), optical disks (for example, compact disk (CD); digital versatile disk (DVD)), smart cards, flash memory devices (for example, card; stick; key drive), random access memories (RAM), read-only memories (ROM), programmable ROMs (PROMs), erasable PROMs (EPROMs), electrically erasable PROMs (EEPROMs), registers, removable disk, and any other suitable medium for storing software and / or instructions that can be accessed and read by a computer. The computer-readable medium can reside in the processing system, external to the processing system, or distributed across multiple entities including the processing system. The computer-readable medium can be embodied in a computer program product. By way of example, a computer program product can include a computer-readable medium in packaging material. Those skilled in the art will recognize how to best implemen the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

[0046] A "processor" means a device that can be configured to perform the various functions recited in the disclosure, either alone or in conjunction with other devices. Examples of a "processor" include a microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic device (PLD), a programmable logic controller (PLC), a state machine, gated logic, and discrete hardware circuits. The phrase "processing system" is used to refer to one or more processors that can be included in a single device or distributed across multiple physical devices.

[0047] An "instruction" means data that can be used to specify a physical or logical operation that can be performed by a processor. Instructions should be interpreted broadly to include code, code segments, program code, programs, sub-programs, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, hardware description languages, middleware, and the like, whether in software, firmware, hardware, microcode, and otherwise.

[0048] Various embodiments can be implemented in any of a wide variety of computing devices. A computing device typically will include a processor coupled to volatile memory and a mass storage device such as a disk drive. The computing device also can include a floppy disk drive, a solid state drive, and a compact disc (CD) drive coupled to the processor. The computing device also can include a plurality of connector ports (such as USB or FireWire™ connector jacks) coupled to the processor for establishing data connections or housing external memory devices, or other network connection circuitry for establishing network interface connections from the processor to a network or bus (such as a local area network coupled to other computers and servers, the Internet, the public switched telephone network, and / or a cellular data network). The computing device also can include a trackball or touchpad, a keyboard, and a display all coupled to the processor.

[0049] Various embodiments also can be implemented in any of a wide variety of server devices that are commercially available. Such a server typically includes a processor coupled to volatile memory and a mass storage device such as a disk drive. The server also can include a floppy disk drive, a compact disc (CD) or DVD disc drive coupled to the processor. The server also can include a network access port coupled to the processor for establishing network interface connections with a network (such as a local area network coupled to other computers and servers, the Internet, the public switched telephone network, and / or a cellular data network).

[0050] The foregoing description of the aspects of the disclosure has been provided for the purposes of aiding in the understanding of the present disclosure and is not intended to limit the disclosure in any way. Far variations of the aspects of the disclosure described herein will become apparent to those of ordinary skill in the art upon reading the foregoing description. For example, the principles of the disclosure can be applied to other types of devices and / or systems. It is intended that the scope of the disclosure be defined by the claims and their equivalents. It is intended that each of the example embodiments and examples described herein can include, consist essentially of, or consist of, any of the combination of the elements recited herein.

[0051] In view of the exemplary systems described above, methodologies that can be implemented in accordance with the disclosed subject matter have been described with reference to several flow diagrams. While for purposes of simplicity of explanation, the methodologies are shown and described as a series of blocks, it is to be understood and appreciated that the claimed subject matter is not limited by the order of the blocks, as some blocks can occur in different orders and / or concurrently with other blocks from what is depicted and described herein. Moreover, not all illustrated blocks can be required to implement the methodologies described herein. Additionally, it should be understood that each block and / or combination of blocks can be implemented by special purpose hardware-based computer systems which are designed and constructed to perform the associated functions / acts and / or combinations of special purpose hardware-based computer systems.

[0052] It should be understood that any patents, publications, or other disclosures that are referred to herein are hereby incorporated by reference in their entirety, whether or not such information is printed in the body of the specification or in a separate paragraph labeled "incorporated by reference." In the event of an inconsistency between the present disclosure and the disclosure contained in any incorporated-by-reference publication, the present disclosure will prevail. Thus, to the extent necessary, the disclosure herein supersedes any discordant materials that can be present in any such incorporated-by-reference publications. Any material, or portion thereof, that is said to be incorporated by reference herein, but which contradicts the present disclosure, is only incorporated to the extent that it is consistent with the present disclosure.

Claims

1. A material handling system comprising: a storage rack having vertically spaced levels; a vertical lift having a vertical support structure positioned proximate the storage rack and having vertically aligned first and second carriages independently positionable along the vertical support structure; a dual vertical drive system configured to position at least one of the vertically aligned first and second carriages at a selected level of the vertical support structure; and a processor subsystem in communication with the dual vertical drive system to: selectively position the vertically aligned first and second carriages at respective selected levels along the vertical support structure so as to avoid collisions between the vertically aligned first and second carriages, wherein the dual vertical drive system includes drive belts on a front side of the vertical support structure, wherein the drive belts are laterally offset from one another.

2. The material handling system of claim 1, wherein each vertically spaced level defines a plurality of storage locations accessible from an adjacent aisle.

3. The material handling system of claim 1, further comprising at least one infeed conveyor and at least one outfeed conveyor adjacent the vertical support structure served by a selected one of the vertically aligned first or second carriages.

4. The material handling system of claim 1, further comprising: a first vertical portion of the vertical support structure including an overlapping section and a first exclusive section above the overlapping section; and a second vertical portion of the vertical support structure including the overlapping section and a second exclusive section below the overlapping section.

5. The material handling system of claim 4, wherein: at least one infeed conveyor and at least one outfeed conveyor adjacent a level of the first exclusive section and served by the vertically aligned first carriage; and at least one infeed conveyor and at least one outfeed conveyor adjacent a level of the second exclusive section and served by the second carriage.

6. The material handling system of claim 4, wherein: the first vertical portion is coextensive with the first exclusive section and spaced apart from the second vertical portion, the second vertical portion being coextensive with the second exclusive section; and the processor subsystem is further configured to position the vertically aligned first carriage within the first exclusive section and selectively position the second carriage within the second exclusive section to prevent collisions.

7. A vertical lift comprising: a vertical support structure; first and second carriages housed for vertical movement along the vertical support structure, each of the first and second carriages independently positionable along respective first and second vertical portions of the vertical support structure, wherein at least one of the first and second vertical portions of the vertical support structure overlap; a dual vertical drive system configured to position the first carriage at a selected level within the first vertical portion of the vertical support structure and to position the second carriage at a selected level within the second vertical portion of the vertical support structure; and a processor subsystem in communication with the dual vertical drive system to: ​ ​ ​ ​ ​ The first and second carriages are selectively positioned at respective selected levels along the vertical support structure to avoid colliding with each other, wherein the dual vertical drive system includes drive belts that are laterally offset from each other on a front side of the vertical support structure.

8. The vertical lift of claim 7, wherein: the first vertical portion includes an overlap section and a first exclusive section above the overlap section; and the second vertical portion includes an overlap section and a second exclusive section below the overlap section.

9. The vertical lift of claim 8, wherein the first and second carriages are positionable to service at least one infeed conveyor and at least one outfeed conveyor adjacent to the vertical support structure.

10. The vertical lift of claim 8, wherein: the first carriage is positionable to service at least one infeed conveyor and at least one outfeed conveyor adjacent to a level of the first exclusive section; and the second carriage is positionable to service at least one infeed conveyor and at least one outfeed conveyor adjacent to a level of the second exclusive section.

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