Material handling apparatus with delivery vehicles and recirculation

Abstract

A method and apparatus are provided for sorting items to a plurality of sort destinations. The items are fed into the apparatus at an input station having a scanning station. The scanning station evaluates one or more characteristics of each item. The items are then loaded onto one of a plurality of independently controlled delivery vehicles. The delivery vehicles are individually driven to sort destinations. Once at the appropriate sort destination, the delivery vehicle ejects the item to the sort destination and returns to receive another item to be delivered. A re-induction conveyor may be provided for receiving select items from the vehicles and conveying the items back to the input station for re-processing. Additionally, a controller is provided to control the movement of the vehicles based on a characteristic each item being delivered by each vehicle. The system may also include vehicles having edge-detection assemblies for detecting items being loaded onto or discharged from the vehicles.

1 . An apparatus for sorting a plurality of items, comprising:
 a plurality of sort destinations;   a plurality of vehicles for delivering items to the sort destinations;   a controller for providing signals for controlling operation of one of the vehicles carrying one of the items to one of the sort destinations;   a detector for detecting an identification characteristic for each item;   a second detector for detecting a second characteristic for each item;   wherein the controller is configured to determine which of the sort destinations a first of the items is to be delivered based on the identification characteristic detected for the first item and to control the operation of a first of the vehicles so that the position of the first vehicle relative to the determined sort destination varies in response to a second characteristic of the first item.   
     
     
         2 . The apparatus of  claim 1  comprising a second detector for detecting the second characteristic for each item wherein the second characteristic is the height, length, width or weight of the item. 
     
     
         3 . The apparatus of  claim 2  wherein the sort destinations are vertically spaced apart from one another and the vehicles are moved vertically to deliver the items to the sort destinations. 
     
     
         4 . The apparatus of  claim 3  wherein the controller is configured to control the operation of the first vehicle in response to the second characteristic for the first item so that the vertical position of the first vehicle relative to the determined sort destination varies in response to the second characteristic. 
     
     
         5 . The apparatus of  claim 2  comprising a loading mechanism for loading items onto the delivery vehicles wherein the second detector is positioned along the loading mechanism. 
     
     
         6 . The apparatus of  claim 1  wherein each vehicle comprises a transfer mechanism for transferring the items to the sort destinations. 
     
     
         7 . The apparatus of  claim 1  wherein the vehicles are independently operable and each vehicle includes an onboard energy source for powering the vehicle. 
     
     
         8 . The apparatus of  claim 1  comprising a guide for guiding the vehicles to the sort destinations wherein the guide comprises a vertical section for moving the vehicles vertically. 
     
     
         9 . The apparatus of  claim 1  wherein the sort destination comprises an output bin having a rearward end through which the item is discharged into the output bin. 
     
     
         10 . The apparatus of  claim 9  wherein the output bin comprises an open rearward end. 
     
     
         11 . The apparatus of  claim 10  wherein the output bin comprises a displaceable or collapsible rearward wall. 
     
     
         12 . A method for sorting a plurality of items into a plurality of sort locations, comprising the steps of:
 loading an item onto a vehicle;   detecting an identification characteristic of the item;   detecting a second characteristic of the item;   determining the output bin to which the item is to be delivered based on the identification characteristic;   displacing the vehicle to the determined output bin;   controlling the position of the vehicle relative to the output bin based on the detected second characteristic;   discharging the item from the vehicle into the output bin;   displacing the vehicle away from the output bin so that a second item can be loaded onto the vehicle.   
     
     
         13 . The method of  claim 12  wherein the step of driving the vehicle comprises driving the vehicle along a guide. 
     
     
         14 . The method of  claim 12  wherein the guide comprises a surface and the vehicle comprises a rotatable element, wherein the step of driving a vehicle along a guide comprises driving the rotatable element along the surface of the guide. 
     
     
         15 . The method of  claim 12  wherein the sort locations are vertically separated from one another and the step of driving the vehicle comprises driving the vehicle in a vertical direction. 
     
     
         16 . The method of  claim 15  wherein the step of controlling the position comprises controlling the vertical position of the vehicle relative to the sort destination in response to the detected second characteristic. 
     
     
         17 . The method of  claim 1  wherein the vehicle comprises a transfer mechanism and the step of loading comprises operating the transfer mechanism. 
     
     
         18 . The method of  claim 12  comprising the step of conveying the item toward a loading location wherein the step of loading the item on the vehicle comprises loading the item at the loading location. 
     
     
         19 . The method of  claim 18  wherein the step of detecting an identification characteristic occurs during the step of conveying the item toward the loading location. 
     
     
         20 . The method of  claim 19  wherein the step of detecting a second characteristic occurs during the step of conveying the item toward the loading location.