WO2014011459A1

WO2014011459A1 - Lift automated guided vehicle for warehouse tray handling

Info

Publication number: WO2014011459A1
Application number: PCT/US2013/049191
Authority: WO
Inventors: Louis BORDERS; Stephen Derby; Gene ECKERT; David Brown
Original assignee: Mercury Capital Management L.L.C.
Priority date: 2012-07-11
Filing date: 2013-07-03
Publication date: 2014-01-16

Abstract

The lift automated guided vehicle ("lift AGV"} includes a wheeled, powered frame having a dock end and an opposed rear end and configured for bi-directional movement between aisles of storage racks storing trays of goods within storage compartments of the rack. The lift AGV includes a lower bi-directional buffer conveyor extending between the dock end and the rear end of the frame; a lift secured to the dock end of the frame and configured for securing and moving trays on to and off of a mobile robot tray delivery device adjacent the dock end of the frame, and optionally onto and off of the lower buffer; and a pick-and-place head secured to a rear-end. The pick-and-place head is configured for movement of a tray onto and from the lower bi-directional buffer conveyor in at least a direction into and out of a storage compartment.

Description

LIFT AUTOMATED GUIDED VEHICLE FOR WAREHOUSE TRAY HANDLING Cross-Reference to Related Applications

£0001] This Application claims the benefit of U.S. Provisional Patent Application Serial Number 61/741,065 that was filed on July 11, 2012 entitled Lift

AVG For Warehouse Tray Handling".

Technical Field

£0002] This disclosure relates to automated goods to delivery systems utilized within warehouses for receiving a great variety of different types of goods and for delivering orders of selected goods, and in particular relates to a lift automated guided vehicle that facilitates handling of such goods .

Background Art

£0003] In the field of shipping to delivery station systems,, many efforts have been undertaken to minimize manual labor within a warehouse that receives varying types of goods . Such goods are then broken down and placed within easily transportable trays for movement to storage cks . The trays must then be withdrawn from, storage and transported to automated pick-and-pack conveyor stations to fill deliver totes moving along the conveyor. Trays that are partiall emptied must be returned to the storage racks. Packed delivery totes or pallets of totes must be transported from the pick-and- pack conveyor stations to a shipping delivery station for out-of-warehouse distribution to a retail outlet or an end user consumer.

[0004] For example, O.S. Patent No. 5,544,396 to Castaldi et al . that issued on August 13, 1996 shows an "Automated Storage and Retrieval System" utilizing two opposed columnar arrays that define a plurality of vertically spaced tray receiving recesses . An extraction device is operable between the arrays for inserting and extracting trays frora the arrays for movement of the trays out of the storage arrays and transport to a next station in processing goods held within the trays. U.S. Patent No. 7,110, 855 that, issued to Leisimian on September 19, 2006 shows a next station in such an automated goods to delivery system, wherein a plurality of pick modules are aligned adjacent a conveyor upon which goods-holding totes move along while manual operators select ordered goods frora storage trays held within the various pick modules. Some of the pick modules include vertical carousels or two pod horizontal carousels.

[0005] Such a system also utilises automated robots for moving trays and totes from station-to-station within the warehouse. U.S. Patent Ho. 7,008,164 that issued on March 7, 2006 to Rokkaku shows such an automated robot for moving goods-containing trays and refers to the automated robot as a self-propelling dolly which is shown in Figures 1 - 3 at reference numeral . The self-propelling dolly of Rokkaku also shows a top surface having plural, automated conveyors for moving trays onto and off of the top surface in delivering the trays or other such products about a warehouse. It is also known in automated goods to delivery systems to utilize vehicles referred to as an "automated guided vehicle" (hereinafter occasionally referred to as an "AGV" ) . For example, U.S. Patent 8,447,448 that issued on May 21, 2013 to Scheuerman et al. shows an "Automated, Guided ^'Vehicle^**' for transporting material along a defined path. Typically an AGV is utilized for more limited movement than a mobile robot and for transporting greater weight than a mobile robot, such as for transporting palletized freight on a top surface of the AGV to a receiving and processing station for breaking down large quantities of goods . The goods are broken down into individual storage trays with, for example, one or a few open top cardboard cases of cans of soup, that are transported by mobile robots or other tray delivery devices such as a conveyor or fork truck, etc., to a storage location in the warehouse .

[0006] While advances have been made in such automated goods to delivery systems, there is still a need for automated machinery that reduces tedious, costly manual labor, and that increases efficiencies in utilisation of limited warehouse space and available energ .

Summary of the Disclosure

[0007] The disclosure includes a lift automated guided vehicle (referred to below occasionally as a "lift AGV") for handling warehouse trays stored in a storage rack. The storage rack includes storage compartments for storing one or more trays, and the storage compartments each include an entryway for placing and removing the trays through the entryway. The entr ways define a storage rack entryway vertical plane about parallel to the entryways. £0008] The lift AGV includes a wheeled, powered frame having a dock end and ah opposed rear end and the lift AGV is configured for bi-directional movement along a horizontal axis about parallel to a lower edge of the storage rack entryway vertical plane. The frame includes a lower bi-directional buffer conveyor extending between the dock end and the rear end of the frame . The lower buffer is configured for bi-directional movement, of trays upon the lower buffer conveyor between the dock end and the rear end of the f ame. The lower buffer conveyor is also dimensioned to hold at least one tray and preferably two o more trays in side-by-side association and two or more trays in stacked vertical association. A lift is secured to the dock end of the frame and is configured for securing and moving trays on to and off of a mobile robot or other tray delivery device located adjacent the dock end of the frame . A pick-and-place head is secured to one of either the lift or a rear-end lift secured to the rear end of the frame. The pick-and-place head is configured for movement of a tray onto and from the lower bi-directional buffer conveyor in at. least, a direction into and out of a storage compartment -

[0009] In a further embodiment, the lift AGV also includes the lift, having a support structure that has a plurality of vertical posts extending above the frame of the lift AGV. Lift guide struts are adjustably secured to top ends of the posts. A mechanical lift, controller is secured to the lift guide struts and has at. least two grab arms secured to the controller. The mechanical lift controller may be any mechanical lift controller means for achieving the described function, such as an electric motor turning a gear or gear box to move a cable or chain to perform lifting and positioning, and/or an electric motor turning a worm-drive gear and treaded shaft, and/or hydraulic or pneumatic motors or compressors and fluid drive pistons, such as are known in the art for performing the described functions. The mechanical controller is also configured for horizontal movement of the grab arms along the adjustable guide struts, and is configured for vertical movement of the grab arms beyond the dock end of the frame . The mechanical controller may also control the grab arras for grasping movement toward each other to grasp trays supported on a mobile robot adjacent the dock end of the frame. The mechanical controller may control the lift to move the grab arms and a grabbed tray between the arms in a vertical direction to lift, the trays off of the mobile robot, and may then move the grab arms in a horizontal direction to place the trays over the lower buffer. The controller then moves the grab arms in a vertical direction to place the trays onto the buffer for storage on the buffer. The mechanical controller may also be configured to operate in a reverse sequence to control the grab arms to remove the stored trays from the buffer arid to place them on the mobile robot or other tray delivery device.

[0010] In another embodiment of the lift AGV, a rear-end lift is secured to the rear end of the f ame. The rear-end lift includes a first lift post and a second lift post extending vertically upward from the frame of the automated guided vehicle. The pick-and-place head is secured between the lift posts, and a second mechanical controller is secured to the lift AGV frame and connected to at least one of the lift posts for selectively moving the pick-and-place head from adjacent the lower buffer vertically above the lower buffer and back to adjacent the lower buffer. in this iabodiment , the pick-and- place head has a first, end secured ad eent the rear end of the frame, and also includes at least a first telescoping grabber adjacent the first end. The telescoping grabber is configured for extending from the head into and out of a storage compartment of the storage rack and is also configured for grabbing a first, tray within the storage compartment and moving the first, tray onto the pick-and-place head. The head also has a first automated roller conveyor secured to and adjacent to the telescoping grabber. A first holding buffer having a bidirectional conveyor is secured to a second end of the pick-and-place head, and the second end is opposed to the first end of the head and is secured adjacent, the automated roller conveyor. The first holding buffer is configured for receiving the first tray from the automated roller and holding the first tray removed from the storage compartment while the lower buffer and automated roller optionally perform either placement of a second tray in the storage compartment or removal of a third tray from the storage compartment before returning the first tray on the first holding buffer either into the storage compartment or upon the lower buffer.

[0011] In another aspect of this embodiment of the lift AGV, the first tray within the storage compartment has a longitudinal length parallel to an axis of extension of the at least first telescoping grabber, and the at least first telescoping grabber is configured for extending from the pick-and-place head into a storage compartment of the storage rack a distance greater than the longitudinal length of the first tray. This permits the telescoping grabber to grab at least the third tray stored within the storage compartment , wherein the third tray is stored in a location further from the pick-and- place head than t e first tray.

£0012] In this embodiment, the pick-and-place head may also include a second automated roller conveyor secured to and adjacent to the telescoping grabber and dimensioned so that a first tray may be supported and moveci by the first automated roller conveyor while a second tray is supported and moved by the second automated roller conveyor. A second holding buffer having a bi-directional conveyor may also be secured adjacent the first holding buffer. The second holding buffer is dimensioned so that the first tray may be supported and moved by the first holding buffer while the second tray is supported and moved by the second holding buffer .

[0013] In a further aspect of this embodiment, an overflow buffer having a bi-directional conveyor may be secured above the lower buffer and adjacent the back end of the lift AGV frame. The overflow buffer is structured so that whenever the vertically adjustable pick-and-place head is positioned adjacent the overflow buffer, the overflow buffer may receive and hold trays moved onto the overflow buffer by the automated rollers of the pick-and- place head. The overflow buffer may then hold the trays removed from the storage compartment while the lower buffer and automated roller optionally perform either placement of a second tray in the storage compartment, or removal of a third tray from the storage compartment, before returning the trays on the first holding buffer into one of the storage compartment or upon the lower b ffer ,

[0014] In yet a further embodiment, the lift AGV includes the lift being secured adjacent the dock end of the frame and the pick-and-place head being secured to the rear-end lift. In this embodiment, the lift AG also includes an upper bi-directional buffer conveyor that is attached to and extends between upper buffer supports secured between the frame and the upper buffer. The upper buffer also extends between the dock end and back end of the frame above the lower buffer and about parallel to the lower buffer. Like the lower buffer conveyor, the upper buffer conveyor is dimensioned to hold at least one tray and preferably two or more trays in side-by-side association. The upper buffer is also constructed for bi-directional movement and storage of trays, and is configured for at least one of receiving and delivering trays to at least one of the lift and the pick-and-place head to facilitate removal of stored trays and replacement of trays back into storage within the compartments of the storage rack.

[0015] In a further aspect of the lift AGV having the upper buffer conveyor, the rear-end lift has support structures including a first lift post secured adjacent a first upper buffer support and a second lift post secured adj cent a second upper buffer support. The first and second lift posts extend in parallel association vertically above the rear end of the frame. A lift mount is secured to and extends between the lift posts. A third mechanical lift controller {such as an electric motor turning a geared shaft moving chains linked to the lift mount) selectively moves the lift mount from adjacent the lower bi-directional buifer conveyor to adjacent the upper bi-directional buifer conveyor and to any locations between the lower and upper buffer conveyors. The third mechanical lift controller may be any mechanical lift controller means for achieving the described function, such as an electric motor turning a gear or gear box to move a cable or chain to perform lifting and positioning, and/or an electric motor turning a worm-drive gear and treaded shaft, and/or hydraulic or pneumatic motors or compressors and fluid drive pistons, such as are known in the art for performing the described functions .

[0016] This embodiment may utilise an alternative bracket pick-and-place head. The alternative bracket pick-and-place head includes a first rectangular bracket having a first end secured to the lift mount. A longitudinal beam having a front, end secured to the first rectangular bracket at the lift mount extends in a direction perpendicular to the lift posts. A second rectangular bracket surrounds and is secured to the longitudinal beam. A first telescoping bar extender is secured to a top end of the first bracket, and a second telescoping bar extender is secured to a top end of the second bracket. A grab bar extends between ends of the telescope extenders. A pivot, stem is pivotally secured to the grab ba . This bracket pick-and-place head is constructed so that, when the pivot stem is pivoted to overlie the grab bar, the telescoping bar extenders extend the grab bar into a storage compartment of the storage rack a predetermined distance. At the predetermined distance the pivot stem pivots away fro overlying the grab bar and extends between a first and second tray, so that the telescoping bar extenders may then retract to pull the first tray onto a beam holding buffer having a bi-directional conveyor. The beam holding buffer is supported upon the longitudinal beam, and has a length sufficient to support at least two trays in side-by-side association. The first tray may be moved in one of either a first direction on the beam holding buffer toward and onto the upper buffer, or in a second direction away frora the upper buffer for storage on the bears holding buffer. The bracket pick-and-place head may then optionally perform eithe placement of a second tray frora the beam holding buffer by movement of the buffer conveyor to a location on the beam holding buffer between the rectangular brackets for placement in the storage compartment. Alternatively, the bracket pick-and-place head may perform removal of a third tray from the storage compartment onto the beam holding buffer before returning the first tray on the beam holding buffer back into the storage compartment..

[0017] In another aspect of this embodiment , the first tray within the storage compartment has a longitudinal length parallel to an axis of extension of the first and second telescoping bar extenders, and the first and second telescoping bar extenders are configured for extending from the braclcet pick-and-place head into a storage compartment of the storage rack a distance greater than the longitudinal length of the first tray. This permits the telescoping bar extenders to grab at least the third tray stored within the storage compartment, wherein the third tray is stored in a location further from the pick-and-place head than the first tray. £0018] The disclosure also includes a method of removing and replacing trays from storage compartments defined within a storage rack with the lift AGV described above. The method includes, extending at least a first telescoping grabber from a pick-and-place head secured adjacent the rear end of the frame of the vehicle so that the telescoping grabber extends into a storage compartment; grabbing a first tray within the compartment and moving it onto the pick-and-place head; moving the first tray from the pick-and-place head onto the lower buffer; moving the tray on the lower buffer to place the first tray adjacent the lift; and, then, moving the first tray off of the lift AGV and on to a tray delivery device such as a mobile robot adjacent the dock end of the frame with the lift .

[0019] The method may also include, before the moving the first tray onto the lower buffer step, moving the first tray onto a holding buffer of the pick-and- place head. Additionally, the method may include extending the telescoping grabber from the pick-and-place head to place a second tray from the holding buffer of the pick-and-place head into the storage compartment. Another method facilitated by the present lift AGV includes, before the aforesaid step of moving the tray off of the lift AGV, moving the first tray on at least one of the lower buffer and a holding buffer, while the lift AGV frame is in motion moving in a direction away from or toward the storage compartment that held the first tray.

[0020] An additional method includes extending the telescoping grabber from the pick-and-place head into the storage compartment to grab a third tray; moving the third tray onto the pick-and-place head moving the third tray from the pick-and-place head onto the lower buffer; and then moving the first tray from the holding buffer back into the storage compartment.

[0021] It is noted that the lift AGV is also constructed so that the pick-and-place head and the alternate pick-and-place head may ^'remove trays from and place trays into storage racks on opposed sides of the lift AGV, wherein each opposed side is about parallel to the vertical storage rack entryway plane. In other words, one lift AGV may work in an aisle between two storage racks disposed in parallel association on opposed sides of the lift AGV.

[0022] It can be seen that the present disclosure, by use of the buffers on the lift AGV, provides for storage on the lift AGV of many trays prior to placing the trays in the various storage compartments of the storage rack or prior to placement of the trays on the mobile robots that move the trays from the lift AGV and storage rack area of a warehouse to other warehouse locations. The storage capacity of the various buffers therefore allows the mobile robots to go about other tasks rather than being idle at the lift AGV awaiting one-by-one removal fro the robot and placement of each tray in a single layer storage rack before moving a second tray f om the mobile robot .

[0023] It is noted that the lift AGV has capacity to remove trays stored on the mobile robots in a side-by- side disposition or in a stacked disposition. Additionally, because the telescoping grabbers and/or telescoping bar extenders may extend substantially beyond a length of a single tray, storage racks may be utilized having multiple vertical layers of trays, wherein trays from a second layer may be grabbed and moved to a buffer while trays from a front or first layer are removed, temporarily stored on the lift AGV holding buffer, and moved back into the storage rack so that the second tray may be moved from the lift AGV to other warehouse locations. This minimises necessary storage area for a specific quantity of trays of goods, and increases a variety of differing goods containing trays that may be stored in a single storage rack.

[0024] Accordingly, it is a general purpose of this disclosure to provide a lift AGV for warehouse trays that overcomes deficiencies of the prior art.

[0025] It is a more specific purpose to provide a lift AGV fo handling warehouse trays that minimizes time necessary for a mobile robot or other tray delivery device to deliver trays to the lift AGV, and that minimizes storage area requirement for storing trays of goods .

[0026] These and other purposes and advantages of the present, lift AGV for handling warehouse trays will become more readily apparent when the following description is read in conj nction with the accompanying drawings .

Brief Description of the Drawings

[0027] Figure 1 is a simplified diagram showing representative processing steps in a warehouse utilizing a shipping to delivery system which is a working environment for the lift AGV of the present disclosure. £0028] Figure 2 is a rear perspective view of a lift AGV constructed in accordance with the present disclosure .

£0029] Figure 3 is a fragmentary rear view of a pick-and-place head, of the Figure 2 lift AG .

£0030] Figure 4 is a front perspective view of the Figure 2 lift. AGV.

[0031] Figure 5 is a raised perspective view of a storage rack defining storage compartments within the rack and including four vertical layers of trays, wherein the lift AGV of the present disclosure removes and replaces trays within the storage compartments .

[0032] Figure 6 is a side plan view of the Figure 2 lift AGV adjacent, the Figure 5 storage rack.

[0033] Figure 7 is a raise perspective view of the Figure 5 storage rack and with the Figure 2 lift AGV adj acent the rack .

[0034] Figure 8 is a front perspective view of an alternative lift AGV having an upper buffer conveyor and a bracket pick-and-place head positioned adjacent a storage rack.

[0035] Figure 9 is a side perspective view of a bracket pick-and-place head adjacent a storage rack.

[0036] Figure 10 is a side perspective view showing the Figure 9 bracket pick-and-place head extracting a tray from the storage rack.

[0037] Figure 11 is a side perspective view showing the Figure 10 bracket pick-and-place head positioning the tray on a beam holding buffer.

[0038] Figure 12 is a side perspective view showing Figure 10 bracket pick-and-place head extracting a third tray from the storage rack. £0039] Figure 13 is a side perspective view showing three trays on trie beam holding buffer of the Figure 10 braclcet. pick-and-place head.

[0040] Figure 14 is a side perspective view showing the Figure 10 bracket pick-and-place head raised up by a rear-end, lift to be adjacent an upper buffer of the lift AGV..

[0041] Figure 15 is a front perspective fragmentary view of the Figure 8 lift AGV showing trays on an upper buffer and a lift lowering a tray from the upper buffe .

[0042] Figure 16 is a front perspective view of the Figure 8 lift AGV showing trays on the upper buffer and in a side-by-side association on a mobile robot secured adjacent a dock end of the lift AGV.

[0043] Figure 17 is a side perspective view of a mobile robot supporting qoods-containinq trays stored on the robot in a stacked association.

[0044] Figure 18 is a side perspective view of a mobile robot having trays stored on the robot in stacked association and adjacent a lift of the Figure 3 lift AGV and having one tray transferred onto a lower buffer of the lift AGV while other trays are supported by the lift.

[0045] Figure 19 is a side perspective view of a mobile robot having trays stored on the robot in stacked association and adjacent a lift of the Figure 3 lift AGV and being transferred onto a lower buffer of the lift AGV as one stack of tr ys.

Preferred Embodiments of the Disclosure

[0046] Referring to the drawings in detail, FIG. 1 shows a working environment for a lift automated guided vehicle which is generally designated by the reference numeral 10 (hereinafter referred to occasionally as a "lift AGV") . The working environment is shown

^•schematically as a warehouse 12 having an entry 14 for receiving a wide variety of goods. The warehouse 12 shows schematically an automated goods to delivery system 16 that includes four primary stations. First the goods arrive at a Receiving and Processing Trays Station 18. After like and similar goods are processed into trays, they are moved by tray delivery devices such as mobile robots 20 to a Storage Rack Station 22, wherein the goods are taken from the mobile robot 20 fay the lift AGV 10 and stored for later access in the storage racks 24 of the Storage Rack Station 22. The stored trays may then be raoveci out of the storage racks 24 by the lift AGV 10 to a mobile robot 20 for transfer to a Robotic Pick And Pack Station 26, and then back to the Storage Rack Station 22, as indicated by the bi-directional arrow 28. After totes 30 moving along the Robotic Pick And Pack Station 26 are filled with a predetermined selection of goods, the totes 30 are then transported by the mobile robots 20 to a Shipping Delivery Station 32 for processing to delivery out of an exit 34 of the warehouse 12 for transport to an end user (not shown} . All of the stations 18, 22, 26, 32, mobile robots 20 and lift. AVGs 10 are controlled by a central controller 35 that transmits control signals to those components to fulfill performance requirements. Such a central controller 35 may be any central controller means, such as a computer and wireless communication systems, for performing the described functions. FIG. 1 shows that, the lift AGVs 10 move along between one or more storage racks 24 for removal of trays out of, and for replacement of trays in to the storage rack. Details of the lift AGV 10 of the present disclosure are described belo .

_.[0047] As best shown in FIGS. 2 - 4, an exemplary lift AGV 10 of the present disclosure is shown for handling warehouse trays stored in a storage rack. FIG. 5 shows an exemplary storage rack 40. The storage rack 40 includes a plurality of storage compartments 42 for storing one or more trays 44. The storage compartments 42 each include an entryway 46 for placing and removing the trays 44 through the entryway 46. The entry ays 46 define a storage rack entryway vertical plane 48 (as shown in hatch lines in FIG. 5} about parallel to the entryways 46.

[0048] The exemplary lift AGV shown in FIGS. 2 - 4, and 6 - 7 includes a wheeled, powered frame 50 having a dock end 52 and an opposed rear end 54. The lift AGV 10 is configured for bi-directional movement along a horizontal axis {represented by bi-directional arrow 56 in FIG. 5} about parallel to a lower edge 57 of the storage rack entryway vertical plane 48 {shown only in FIGs . 5 and 7} . The frame 50 includes a lower bidirectional buffer conveyor 58 extending between the dock end 52 and the rear end 54 of the frame 50. The lower buffer 58 is configured for bi-directional movement of trays 44 upon the lower buffer conveyor 58 between the dock end 52 and the rear end 54 of the frame 50. The lower buffer conveyor 58 is also dimensioned to hold at least one tray and preferably two or more trays 44 in side-by-side association, as represented by trays 44A and 44B in FIG. 2 two or more trays in stacked vertical association, as represented by trays 44C, 44D in FIG. 2. £0049] A lift is best shown in FIGS. 2 and 4 and is represented -generally by reference numeral 60. The lift 60 is secured to the dock end 52 of the frame 50 and is configured for securing and moving trays 44 onto and off of a tray delivery device such as a mobile robot 62 adjacent the dock end 52 of the frame 50. A pick-and- place head 64 is secured to a rear-end lift 66 secured to the rear end 54 of the frame 50. The pick-and-place head 64 is configured for movement of a tray 44 onto and from the lower bi-directional buffer conveyor 58 in at least a direction into and out of a storage compartment 42.

£0050] The lift AGV 10 also includes the lift 60 having a support, structure 68 that has a plurality of vertical posts 70 extending above the frame 50 of the lift AGV 10. Lift guide struts 72A and 72B are adjustably secured to top ends 74A, 74B of the posts 70. A mechanical lift controller 76 is secured to the lift guide struts 72A, 72B and includes at least two grab arms 78A, 78B secured to the mechanical lift controlle 76. The mechanical lift controller 76 may be any mechanical lift controller means for achieving the described function, such as an electric motor turning a gear or gear box to move a cable or chain to perform lifting and positioning, and/or an electric motor turning a orm- drive gear and treaded shaft,. and/or hydraulic or pneumatic motors or compressors and fluid drive pistons (not shown) , such as are known in the art for moving trays as described herein. For example, the mechanical lift controller may include microprocessor and/or a computer control systems for receiving information from the central controller 35, and for executing command received therefrom. The mechanical lift controller 76 is also configured for horizontal movement of the grab arms 78A, 78B along the adjustable guide struts 72A, 7233, and is also configured for vertical movement of the grab arms 78A, 78B beyond the dock end 52 of the frame 50. The mechanical lift controller may also control the grab arms 78A, 788 for grasping movement toward each other to grasp trays 44 supported on the mobile robot 62 adjacent the dock end 52 of the frame 50.

[0051] The mechanical lift controller 76 may control the lift 60 to move the grab arms 78A, 78B and a grabbed tray 44 between the arms 78A, 78B in a vertical direction to lift the trays 44 off of the mobile robot 62, and may then move the grab arms 78A, 78B in a horizontal direction 56 to place the trays 44 over the lower buffer 58. The mechanical lift controller 76 may then move the grab arms 8A, 78B in a vertical direction to place the trays 44 onto the lower buffer 58 for storage. The mechanical lift controller 76 may also be configured to operate in a reverse sequence to control the grab arms 78A, 78B to remove the stored trays 44 from the lower buffer 58 and to place them on the mobile robot. 62.

[0052] The rear-end lift 66 is secured to the rear end 54 of the frame 50. The rear-end lift. 66 includes a first lift post 80 and a second lift post 82 secured adjacent to two frame vertical posts 70 and extending vertically upward f om the two frame vertical posts 70 adjacent the rear end 52 of the lift AGV 10. The pick-and-piace head 64 is secured between the lift posts 80, 82. A second mechanical controller 84 is secured to the lift AGV frame 50 and connected to at least one of the lift posts 80, 82 for selectively moving the pick-and-piace head 64 from adjacent the lower buffer 58 vertically above t e lower buffer 58 and back to adjacent the lower buffer 58.

[0053] In this embodiment of the lift AGV shown in FIGS, 2 - 4, the pick-and-place head 64 has a first end 86 secured adjacent and between the lift posts 80, 82 at t e rear end 54 of the frame 50. The pick-and-place head 64 also includes at least a first telescoping grabber 88 adjacent the first end 86. The telescoping grabber 88 is configured for extending from the head 64 into and out of a storage compartment 42 of the storage rack 40 and is also configured for grabbing a first tray 44E (shown in FIG. 5) within the storage compartment 42A and moving the first tray onto the pick-and-place head 64. The head 64 also has a first automated oller conveyor 90 secured adjacent to the telescoping grabber . A first. holding buffer 92 having a bi-directional conveyor 94 is secured to a second end 96 of the pick- and-place head 64, and the second end 96 is opposed to the first end 86 of the head 64 and is secured adjacent the automated roller conveyor 94 of the pick-and-place head 64.

[0054] In removing trays from the storage rack 40, the first holding buffer 92 is configured for receiving the first tray 44E after the telescoping grabber 88 has removed the first tray 44E from the storage compartment 42A {shown in FIG. 5} and moved it to the first automated roller 90. The first tray 4E may be stored on the first holding buffer 92 while the pick-and- place head 64 selects a tray from the lower buffer 58, such as tray 44A shown in FIGS. 2 and 3, and positions it into storage compartment 42A. Alternatively, the first tray 44E may be stored on the first holding buffer 92 while the pick-and-place head 64 removes a second tray 44F from the storage compartment 42A and places the second tray 44F on the lower buffer 58 fo subsequent movement to the mobile robot 62. Then the pick-and-place head 64 may move the first tray 44E from the holding buffer back 9.2 back onto the first automated rollers 90 of the head €4. Next, the telescoping grabber 88 places the first tray 44E back into storage compartment 42A., to enable the pick-and-place head 64 to work with a first vertical layer holding the first tray 4E and a second vertical layer holding the second tray 44F of the storage, so that the storage compartments, such as 2A, may have differing kinds of goods in each of the trays 44E, 44F within the storage compartment 42A.

[0055] In another aspect, of this disclosure of the lift AGV 10, the first, tray 44E within the storage compartment 42 has a longitudinal length parallel to an axis of extension of the at least, first, telescoping grabbe 88, and the at least, first telescoping grabber 88 is configured for extending from the pick-and-place head 64 into the storage compartment 2A of the storage rack 40 a distance greater than the longitudinal length of the first tray 44E. This permits the telescoping grabber 88 to grab at least the second tray 4F stored within the storage compartment 42A, wherein the second tray 4F is stored in a location further from the pick-and-place head 64 than the first tray 4E.

[0056] In this embodiment and as shown best in

FIG. 3, the pick-and-place head 64 may also include a second automated roller conveyor 98 secured adjacent to the telescoping grabber 88 and dimensioned so that the first tray 44E may be supported and moved by the first automated rolle conveyor 90 while the second tray 44F is supported and moved by the second automated roller conveyor 98. A second holding buffer 100 having a foi- directional conveyor 102 may also be secured adjacent the first holding buffer 92. The second holding buffer 100 is dimensioned so that the first tray 44E may be supported and moved by the first holding buffer 92 while the second tray 44F is supported and moved, by the second holding buffer 100 of the pick-and-place head 64.

[0057] n a further aspect of this embodiment, an overflow buffe 104 having a bi-directional conveyor 106 may be secured above the lower buffer 58 and adjacent the back end 54 of the lift AGV 10 frame 50. The overflow buffer 104 is structured so that whenever the vertically adjustable pick-and-place head 64 is positioned adjacent the overflow buffer 104, the overflow buffer 104 may receive and hold trays 44 moved onto the overflow buffer 104 by the first or second automated rollers 90, 98 of the pick-and-place head 64. The overflow buffer 104 may then hold the trays 44 removed front. the storage compartments 42 while the lower buffer 58 and automated rollers 90, 98 optionally perform either placement of the second tray 4F in the storage compartment 2A, or perform removal of a third tray 44G from the storage compartment 2A, before returning the trays 44 on the first holding buffer 92 into one of the storage compartment 2A or upon the lower buffer 58.

[0058] FIG. 6 shows a side plan view of the lift AGV 10 of the present disclosure adjacent and working a storage rack 40 for purposes of clarity. FIG. 6 demonstrates that the storage rack 40 may be made of metal framework and storage compartments 42 configured to receive the trays 44 with very modest tolerances to facilitate receipt and discharge of the trays 44, and to minimize material usage to efficient storaqe of the trays 44. FIG. 7 shows a raised perspective view of the lift AGV 10 approaching the storage rack 40 for a sense of relative proportions. It. is to be understood that the storaqe rack 40 may have dimensions rauch greater than the dimensions of the rack 40 show in the illustrations, and may extend hundreds of yards in certain warehouse circumstances . Additionally, the telescoping grabber 88 may extend into a storage compartment 42 as far as practicable in light, of engineering constraints- Current, engineering permits extension of at least about ten to twelve feet, or adequate for about five two-foot trays, and it. is expected that improved engineering with carbon- fiber type of light, strong materials will provided for substantially greater extension.

[0059] An alternative embodiment of a lift AGV 200 is shown in FIGS. 8 and 16, and components of this embodiment of the lift AGV 200 are shown in FIGS. 9 - 15 and 18 - 19. The alternative lift AGV 200 includes a lift 202 being secured adjacent a dock end 204 of a frame 206. The alternative or bracket pick-and-place head 208 is secured to a rear-end lift 210 adjacent a rear end 212 of the frame 206. In this embodiment, the alternative lift AGV 200 also includes an upper bi-directional buffer conveyor 214 that is attached to and extends between upper buffer supports 216A, 216B, 216C and 2I6D secured between the frame 206 and the upper buffer conveyor 214. The upper buffer 214 also extends between the dock end 204 and rear end 212 of the frame 206 above a lower buffer conveyor 218 and about parallel to the lower buffer 218. Like the lower buffer conveyor 218, the upper buffer conveyor 214 is dimensioned to hold at least one tray and preferably two or more trays 244 in side-by-side association. The upper buffer 214 is also constructed for bi-directional movement and storaqe of trays 244, and is configured fo at least one of receiving and delivering trays 244 to at least one of the lift 202 and the bracket pick-and-place head 208 to facilitate removal of stored trays 244 and replacement of trays 244 back into storaqe within storage compartments 242 of t e storage rack 240.

[0060] In a further aspect of the alternative lift AGV 200 having the upper buffer conveyo 214, the rear-end lift 210 has support structures including a first lift post 220 secured adjacent a first upper buffer support 221 and a second lift post 223 secured adjacent a second upper buffe support 222. The first and second lift posts 220, 223 extend in parallel association vertically above the rear end 212 of the frame 206. A lift mount 224 is secured to and extends between the lift posts 220, 222. A third mechanical lift controller 226 (shown in FIGS. S) selectively moves the lift mount 224 from adjacent the lower bi-directional buffer conveyor 218 conveyor to adjacent the upper bi-directional buffer conveyor 214 and to any locations between the lower and upper buffer conveyors 218, 214. The third mechanical lift controller 226 may be any mechanical lift controller means for performing the functions described herein known in the art, such as pneumatic compressors or hydraulic pumps (not shown) connected to pistons and actuated by a controller 226 receiving communications from the central controller 35.

_.[0061] This alternative lift AGV 200 embodiment may utilize the alternative bracket pick-and-place head 208 shown in FlGs. 8 - 14. The alternative bracket pick- and-place head 208 includes a first rectangular bracket 228 having a first end 230 secured to the lift mount 224. A longitudinal beam 232 having a front end 234 secured to the first rectangular bracket 228 at the lift mount 224 extends in a direction perpendicular to the lift poets 220, 223. A second rectangular bracket 236 surrounds and is secured to the longitudinal beam 232. A first telescoping ba extender 238 is secured to a to end of the first bracket 228, and a second telescoping bar extender 250 is secured to a top end of the second bracket 236. A grab bar 252 extends between ends of the the telescope extenders 238, 250. A pivot stem 254 is pi otaily secured to the grab bar 252.

[0062] This bracket pick-and-place head 208 is constructed so that, when the pivot stem 254 is pivoted to overlie the grab bar 252 {not shown} , the telescoping bar extenders 23S_r 250 extend the grab bar 252 into a storage compartment 242 of the storage rack 240 a predetermined distance. At the predetermined distance the pivot stem 254 pivots away from overlying the grab bar 252 and extends between a first and second tray 244, so that the telescoping bar extenders 238, 250 may then retract to pull the first tray 2 4A (shown in FIGS. 10 - 15) onto a beam holding buffer 256 having a bidirectional conveyor 256.

[0063] The beam holding buffer 256 is supported upon the longitudinal beam 232, and has a length sufficient to support at least two trays 244 in side-by- side association. The first tray 2 A may be moved in one of either a first direction on the beam holding buffer 256 toward and onto the upper buffer 214, or in a second direction away from the upper buffer 214 for storage on the beam holcUnq buffer 256. The bracket pick-and-place head 208 may then optionally perform either placement of a second tray 244B from the beaai holding buffer 256 by movement, of the buffer conveyor 256 to a location on the beam holding buffer 256 between the rectangular brackets 228, 236 for placement in the storage compartment 242A. Alternatively, the bracket pick-and-place head 20S may perform removal of a second tray 244B and a third tray 244C from the storage compartment 2 2A onto the beam holding buffer 256 before returning the first tray 244A on the beam holding buffer 256 back into the storage compartment 2 2A, as shown in the sequence of drawings in FIGS. 10-15.

[0064] In another aspect of this embodiment , the first tray 244A within the storage compartraent 242A has a longitudinal length parallel to an axis of extension of the first and second telescoping bar extenders 238, 250, and the first and second telescoping bar extenders 238, 250 are configured for extending from the bracket pick- and-place head 208 into a storage compartment 242A of the storage rack 240 a distance greater than the longitudinal length of the first tray 244A. This permits the telescoping bar extenders 233, 250 to grab at least the third tray 244C stored within the storage compartment 242A, wherein the second tray 2 4B and the third tray 244C are stored in locations further from the pick-and- place head 208 than the first tray 244A. £0065] The disclosure also includes a method of removing and replacing trays 44 from storage compartpaerits 42 defined within the storage rack 40 with the lift AGV described 10 above. The method includes, extending at least a first, telescoping grabber 88 from a pick-and- place head €4 secured adjacent the rear end 54 of the frame 50 of the lift. AGV 10 so that the telescoping grabber 88 extends into the storage compartment. 42A; grabbing a first tray 4 E within the compartment 42A and moving it onto the pick-and-place head 64; moving the first tray 44E onto the lower buffer conveyor 58; moving the lower buffer conveyor 58 to place the first tray 4E adjacent the lift 60; and, then, moving the first tray 44E off of the lift AGV 10 and on to the mobile robot 64 adjacent the dock end 52 of the frame 50 with the lift 60.

[0066] The method may also includes, before the moving the first tray 44E onto the lower buffer conveyor 58 step, moving the first tray 44E onto a holding buffer 92 of the pick-and-place head 6 . Additionally, the method may include extending the telescoping grabber 88 from the pick-and-place head 64 to place a second tray 44 from the holding buffer 92 of the pick-and-place 64 head into the storage compartment 42A.

[0067] An additional method includes extending the telescoping grabber 88 from the pick-and-place head 64 into the storage compartment 42A to grab a third tray 44G; moving the third tray 4G onto the pick-and-place head 64; moving the third tray 4G from the pick-and- place head 64 onto the lower buffer 58; and then moving the first tray 44E from the holding buffer 92 back into the storage compartment 42 . _.[0068] FIGS. 9 - 16 show a sequence of drawings demonstrating how the alternative lift AGV 200 may be used to work more than one vertical layer of trays 44, FIG. 9 is a side perspective view of a bracket pick-and- place head 208 adjacent the storage rack 240 and showing the pick-and-piace having its brackets 228, 236 adjacent a storage compartment 242A and surrounding the first tray 244A. FIG. 10 shows the Figure 9 bracket pick-and-place head 208 extracting the first tray 244A from the storage rack. Fig 11 shows the Figure 10 bracket pick-and-place head 208 positioning the tray on the beam holding buffer 256. FIGA. 12 shows the 10 bracket pick-and-place head 208 extracting the third tray 244C from the storage compartment 242A, after having extracted the second tray 244b from the compartment 2 2A and positioned it next to the first tray 2 A in a storage position on the beam holding buffer conveyor 256. FIG. 13 shows the three trays on the beam holding buffer conveyor 256 of the FIG. 10 bracket pick-and-place head 208. FIG. 14, shows the FIG. 10 bracket pick-and-place head 208 raised up by a rear-end lift 210 so that, the beam holding buffer conveyor 256 is ad acent the upper buffer conveyor 214 of the lift AGV 200. FIG. 15 shows the second and third trays 244C, 244D on the upper buffer conveyor 214 and the lift 202 lowering a tray 244 from the upper buffer conveyor 214 while the beam holding buffer conveyor 256 has positioned the first tray 244A in front of the storage compartment 2 2A. {For purposes of clarity of viewing, many components of the bracket pick-and-place head 208 are not show in FIGS. 15 and 16.) FIG. 16 shows the FIG 8 lift AGV 200 having trays 244, 244C, 244D on the upper buffer and in a side-by-side association on a second mobile robot 258 having a automated conveyor 260 for receiving the trays .244 in side-by-side association . The second mobile robot 258 is secured adjacent the dock end 204 of the lift AGV .

£0069] FIG 17 is a side perspective view of a third mobile robot 262 having a vertical stack supporting tray 264 on the top of the robot for supporting goods- containing trays 244 stored on the robot 262 in a stacked association. FIG. 18 shows the third mobile robot 262 havinq vertically stacked trays 244 adjacent the lift 202 of the alternative lift AGV 200 of FIG. 8 showing one tray 244 transferred onto a lower buffer of the lift AGV while other trays are supported by opposed grab arms 266 the lift 202 (FIG. 18 only shows one of the grab arms 266, but anothe is on the opposed side of the lift 202) . The grab arms 266 are controlled to qrab and lift trays 244 from the third mobile robot 262, to place the trays on the upper buffer conveyor 214 (shown in FIG. 8} and to place trays 244 from the lower buffer conveyor 218 or upper buffer conveyor 214 on to the stack supporting tray 264 of the mobile robot 262. FIG. 19 shows the third mobile robot 262 having trays 244 stored on the robot 262 in stacked association and adjacent a lift 202 of the FIG. S lift AGV and being transferred onto the lower buffer conveyor 218 of the alternate lift AGV 200 as one stack of trays.

[0070] While the present disclosure has been presented above with respect to the described and illustrated embodiments of the lift automated guided vehicle 10, 200 for warehouse tray 44, 244 handling it is to be understood that the disclosure is not to be limited to those illustrations and described embodiments. For example., while the disclosure and illustrations primarily refer to a ^mobile robot 62, 262" as a device for delivering trays to and removing trays from the lift AGV 10, 200. It is to be understood that any tray delivery device, such as a conveyor to which the lift AGV is moved to for loading or off loading, a fork truck, etc., may be an appropriate tray delivery device. Accordingly, reference should be raade primarily to the following claims rather than the forgoing description to determine the scope of the disclosure.

Claims

What is claimed is :

1. A lift automated guided vehicle for handling warehouse trays stored in a storage rack, wherein the storag rack includes storage compartments for storing one or more trays, wherein the storage compartments each include an entryway for placing and removing the trays through the entryway, and wherein the entryways define a storage rack entryway vertical plane about parallel to the entryways, the lift autoraated guided vehicle comprising :

a . a wheeled, powered frame having a dock end and an opposed rea end and configured for bidirectional movement along a horizontal axis about parallel to a lower edge of the storage rack entryway vertical plane, the frame having a lower bi-directional buffer conveyor extending between the dock end and the rear end of the frame and configured for bi-directional movement of trays upon the lower bi-directional buffer conveyor between the dock end and the rear end of the frame, and the buffer conveyor dimensioned to hold at least one tray and two or more trays in stacked vertical association; b. a lift secured to the dock end of the frame and configured for securing and moving trays on to and off of a tray delivery device adjacent the dock end of the frame, and optionally onto and off of the lower buffer; and,

c . a pick-and-place head secured to one of the lift and a rear-end lift secured to the rear end of the frame, and the pick-and-pl ce head being configured for movement of a tray onto and front the lower bi-directional buffer conveyor in at least a direction into and out of a storage compartment ,

2. The lift automated guided vehicle of claim 1, wherein the lift further comprises:

a. a support structure including a plurality of vertical posts extending above the automated guided vehicle frame and having lift guide struts adjustably secured to top ends of the posts;

b. a mechanical lift controller secured to the lift guide struts and having at least two grab arms secured to the controller, the mechanical controller being configured for horizontal movement of the grab arms along the adjustable guide struts, configured for vertical movement of the grab arms beyond the dock end of the frame, and configured for grasping movement of the grab arms toward each other to grasp trays supported on the tray delivery device, so that, the mechanical controller may move the grab arms and a grabbed tray between the arms in a vertical direction to lift the trays off of the tray delivery device, may move the grab arms in a horizontal direction to place the trays over the lower buffer, in a vertical direction to place the trays onto the buffer for storage on the buffer, and the mechanical controller configured to control the grab arms to remove the stored trays from the butter and to place them on the tray delivery device.

3. The lift automated guided vehicle of claim 1, furthe comprising :

a. rear-end lift secured to the rear end of the frame, including a first lift post and a second lift post extending vertically upward from the frame of the automated guided vehicle, the pick-and-place head secured between the lift posts, and a mechanical controller secured to the automated guided vehicle frame and connected to at least one of the lift posts for selectively moving the pick-and-piace head from adjacent the lower buffer vertically above the lower buffer and back to adjacent the lower buffer;

b. the pick-a d-place head having a first, end secured adjacent the rear end of the frame, and including at least a first telescoping grabber adjacent, the first end and configured for extending from the head into and out of a storage compartment and for grabbing a first tray within the compartment and moving it onto the pick-and-piace head; the head also having a first automated roller conveyor secured adjacent, to the telescoping grabber; a first holding buffer having a bi-directional conveyor and secured to a second end of the pick-and- piace head opposed to the first end of the head, and secured adjacent the automated roller conveyor and configured for receiving the first tray from the automated roller and holding the first tray removed from the storage compartment while the lower buffer and automated roller optionally perform placement of a second tray in the storage compartment or removal of a third tray from the storage compartment before returning the first tray on the first holding buffer into one of the storage compartment and the lower buffer. lift automated guided vehicle of claim 3, omprising :

the first tray within the storage compartment having a longitudinal length parallel to an axis of extension of the at least first telescoping grabber;

the at least first telescoping grabber being configured for extending from the pick-and- place head into a storage compartment of the storage rack a distance greater than the longitudinal length of the first tray, so that the telescoping grabber may grab at least the third tray stored within the storage compartment, wherein the third tray is stored in a location further from the pick-and-place head than the first tray.

5. The lift automated guided vehicle of claim 3, wherein the pick-and-place head further comprises a second automated roller conveyor secured adjacent to the telescoping grabber and dimensioned so that the first tray may be supported and moved by the first automated roller conveyor while a second tray is supported and moved by the second automated roller conveyor, and a second holding buffer having a bi-directional conveyor secured adjacent the first holding buffer and dimensioned, so that the first tray raay be sirpportsd and moved by the first holdinq buffer while the second tray is supported and moved by the second holding buffer.

6. The lift automated guided vehicle of claim 3, wherein the automated quided vehicle further comprises an overflow buffer having a bi-directional conveyor and secured above the lower buffer and adjacent the back end of the frame, and configured so that whenever the vertically adjustable pick-and-place. head is positioned adjacent the overflow buffer, the overflow buffer may receive and hold trays moved onto the overflow buffer by the automated roller of the pick-and-place head for holding the trays removed from the storage compartment while the lower buffer and automated roller optionally perform placement of a second tray in the storage compartment, removal of a third tray from the storage compartment, before returning the trays on the first holding buffer into one of the storage compartment and the lower buffer.

7. The lift automated guided vehicle of claim I, wherein the frame further comprises:

a. the lift being secured adjacent the dock end of the frame and the pick-and-place head being secured to the rear-end lift;

b. an upper bi-directional buffer conveyor attached to and extending between upper buffer supports secured between the frame and the Upper buffer, the upper buffer extending between the dock end and back end of the frame above the lower buffer and about parallel to the lower buffer, and the upper buffer conveyor dimensioned to hold at least one tray; and, c. the upper buffer being configured for bi- directional movement and storage of trays, and configured for at least one of receiving and delivering trays to at least one of the lift and the pick-and-place head.

8. The lift automated guided vehicle of claim 7, wherein the rear-end lift further comprises;

a. support structures including a first lift post secured adjacent a first upper buffer support and a second lift post secured adjacent, a second upper buffer support, the first, and second lift posts extending in parallel association vertically above the rear end of the frame;

b. a lift mount secured to and extending between the lift, posts; and,

c. a mechanical lift controller configured for selectively moving the lift mount from adjacent the lower bi-directional buffer conveyor to adjacent. the upper bi-directional buffer conveyor and to any locations between the lower and upper buffer conveyors.

9. The lift automated guided vehicle of claim 8, wherein the piok-and-piace head is a bracket pick-and- place head comprising:

a. a first rectangular bracket having a first end secured to the lift mount, a longitudinal beam having a front end secured to the first rectangular bracket at the lift mount and extending in a direction perpendicular to the lift posts, a second rectangula bracket surrounding the longitudinal beam and secured to the beam;

b. a first telescoping bar extender secured to a top end of the first bracket, a second telescoping bar extender secured to a top end of the second bracket, a grab bar extending between the ends of the telescoping bar extenders, a pivot stem pivotally secured to the grab bar;

c. the bracket pick-and-place head configured so that when the pivot stem is pivoted to overlie the grab bar, the telescoping bar extenders extend the grab bar into a storage compartment of the storage rack a predetermined distance, so that at the predetermi ed distance the pivot stem pivots away from overlying the grab bar and extends between a first and second tray, so that the telescoping bar extenders retract the first tray onto a beam holding buffer having a bi-di ectional conveyor supported by the longitudinal beam, so that the first tray may be moved in one of a first direction on the beam holding buffer toward and onto the upper buffer and a second direction away from the upper buffer for storage on trie beam holding buffer, while the bracket pick-and-place head optionally performs placement of a second tray from the beam holding buffer at a location on the holding buffer betwee the rectangular brackets for placement in the storage compartment, or performs removal of a third tray from the storage compartment, onto the beam holding buffer and then onto the upper buffer for movement to the lift before returning the first tray on the bears holding buffer back into the storage compartment . lift automated guided vehicle of claims 9, omprising :

the first tray within the storage compartment having a longitudinal length parallel to an axis of extension of the first and second telescoping bar extenders;

the first and second telescoping bar extenders being configured for extending from the bracket pick-and-place head into a storage compartment of the storage rack a distance greater than the longitudinal length of the first tray, so that the telescoping bar extenders may grab at least the third tray stored within the storage compartment, wherein the third tray is stored in a location further from the bracket, pick- and-place head than the first tray.

11. The lift automated guided vehicle of claim 1, wherein the lower buffer conveyor is dimensioned to hold at least two trays in side-by-side association, and wherein sid -by-side association means the trays being positioned between the dock end of the frame and the rear end of the frame so that a first of the at least two trays is closer to the dock end of the fame than a second of the at least two trays .

12. The lift automated guided vehicle of ^'claim 7, wherein the upper buffer conveyor is dimensioned to hold at least two trays in side-by-side association, and wherein side-by-side association means the trays being positioned between the dock end of the frame and the rear end of the frame so that a first of the at least two trays is closer to the dock end of the fame than a second of the at least two trays .

13. A method of removing and replacing trays from storage compartments defined within a storage rack with the lift automated guided vehicle of claim 1, the method comprising:

a. extending at least a first telescoping^' grabber from a pick-and-place head secured adj cent the rear end of the frame of the vehicle so that the telescoping grabber extends into a storage compartment ;

to. grabbing a first tray within the compartment and moving it onto the pick-and-place head;

c. moving the first tray onto the lower buffer; d. moving the lower buffer to place the first tray adjacent, the lift; and, e. moving the first tray off of the vehicle and on to a tray delivery device adjacent the dock end of the frame with the lift.

14. The method of claim 13, further comprising, before the moving the first tray onto the lower buffer, moving the first tray onto a holding buffer of the pick-and- place head.

15. The method of claim 14, further comprising, extending the telescoping grabber from the pick-and-place head to place a second tray from the holding buffer of the pick-and-place head into the storage compartment .

16. The method of claim 14, furthe comprising extending the telescoping grabbe from the pick-and-piace head into the storage compartment to grab a third tray," moving the third tray onto the pick-and-place head; moving the third tray from the pick-and-place head onto the lower buffer; and then moving the first tray from the holding buffer back into the storage compartment.

17. The method of claim 13, further comprising, before the aforesaid step of moving the tray off of the lift automated guided vehicle, moving the first tray on at least one of the lower buffer and a holding buffer, while the lift automated guided vehicle frame is in motion moving in a direction away fro or toward the storage compartment that, held the first tray.