Conveyors: power-driven – Conveyor arrangement for selecting among plural sources or... – By a selectively movable stop means
Reexamination Certificate
1999-02-25
2001-05-15
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor arrangement for selecting among plural sources or...
By a selectively movable stop means
Reexamination Certificate
active
06230872
ABSTRACT:
TECHNICAL FIELD
The present invention relates to material handling systems utilizing conveyors, and more particularly relates to a package or parcel transfer and sorting system useful in a hub facility of a package delivery system.
BACKGROUND ART
In a large package delivery system, millions of packages picked up from thousands of locations over a large geographical area must be transported, primarily by truck and airplane, to a correspondingly large number of destinations that are also scattered over a large area. Such delivery services are offered within guaranteed times as short as one day. To meet a rigorous schedule and provide accurate deliveries, a package delivery company must use automated transfer systems to match incoming packages with proper transport that is heading to their destinations.
Belt and roller conveyor systems have often been used in package sorting systems to move packages from incoming loading docks to outgoing transport. Typically, conveyors carry packages unloaded from a truck to a worker who manually sorts them by reading address information on shipping labels attached to the packages. The worker then places the packages onto receiving conveyors or chutes which carry the packages either to a loading dock for loading onto outgoing trucks, or to another sorting station for a narrower breakdown of destinations. A distribution hub in a package delivery system may have as many as 20 to 60 sorting stations operating simultaneously. By providing vertically stacked rows of receiving conveyors, the sorting operation could be accommodated in a relatively small amount of floor space.
To automate handling of articles in conveyor systems, conveyor diverter assemblies have been developed. Examples of conveyor diverters are shown in U.S. Pat. No. 4,798,275 to Leemkuil et. al., and U.S. Pat. No. 4,174,774 to Bourgeois, both of which are incorporated herein by reference. However, such diverters are used primarily to divert articles from a main linear conveyor. Thus, such systems occupy a relatively large amount of space. This problem is overcome by the rotary sorter system shown in U.S. Pat. No. 5,284,252 to Bonnet, assigned to the assignee of the present application. In this system, destination codes on shipping label of packages are machine read, and the packages are transferred onto powered conveyor modules mounted on a rotating distribution assembly. The individual module is then rotated and elevated or lowered into alignment with one of a plurality of destination conveyors that are spaced apart both horizontally and vertically. After such alignment, the modules rollers are operated to discharge the package onto the destination conveyor. In the Bonnet system, packages can be rapidly sorted without human intervention by an apparatus that occupies a small amount of floor space.
For some circumstances, it would be advantageous to have a compact package sorting system that did not require moving a conveyor module holding a package from a loading point to a discharge point.
SUMMARY OF THE INVENTION
The present invention provides an efficient package sorting system in which a stationary matrix of multi-directional conveyor cells sorts packages to a plurality of destination locations. In a preferred embodiment, the matrix delivers sorted packages to a plurality of lift assemblies that further transfer the packages to receiving conveyors or chutes on different levels. According to another preferred aspect of the system, a selectively elevating stop bar is provided to control side transfer between conveyor cells.
Generally described, according to one of its aspects, the present invention provides a system for sorting a stream of objects emanating one-by-one from an object source, comprising: a matrix of stationary conveyor cells, including a plurality of the cells positioned to form at least two transversely extending rows of adjacent conveyor cells and at least two longitudinally extending rows of adjacent conveyor cells, an input cell of the conveyor cells in a first transversely extending row being positioned to receive objects from the object source; a controller connected to operate a plurality of the conveyor cells in the matrix individually to discharge an object thereon in one of a plurality of directions; a plurality of destination locations positioned adjacent to the conveyor cells in at least one of the transverse rows other than the first transverse row; a reader positioned adjacent to the stream of objects to read destination information borne by the objects; the controller being operative responsive to the reader to guide each object received by the input cell from cell to cell through the matrix to a destination location corresponding to the destination information.
In a preferred embodiment, the controller is operative to plan a path for each of the objects from the input cell to a destination location, to monitor availability of successive conveyor cells along the path, and to cause an object to be moved to the next conveyor cell along its path only when the next conveyor cell is available. The system may include a plurality of sensors positioned to sense the passage of objects from one conveyor cell to another, the sensors being connected to the controller. The sensor input is used to guide the packages through the matrix, and to optimize the speed at which a plurality of packages can be sorted.
According to another aspect, the present invention provides a method of sorting objects emanating one-by-one from an object source, comprising the steps of: transferring each of the objects from the object source to a matrix of stationary conveyor cells, the matrix including a plurality of the cells positioned to form at least two transversely extending rows of adjacent conveyor cells and at least two longitudinally extending rows of adjacent conveyor cells, and transferring each of the objects through the matrix from one of the conveyor cells to another and to one of a plurality of destination locations. In a preferred embodiment, the method may further comprise the steps of: reading destination information from each of the objects as the objects enter the matrix; and guiding the objects to one of the destination locations corresponding to the destination information. The method may also comprise monitoring availability of a next conveyor cell in the matrix to which an object is to be moved; and moving the object to the next cell only when the cell is available.
According to yet another aspect, the present invention provides, in a conveyor unit including a plurality of spaced apart rollers extending to a unit edge extending perpendicular to a longitudinal axis of the rollers, a side stop plate assembly, comprising: an elongate stop plate extending parallel to the unit edge and spaced inwardly from the unit edge above the rollers, and defining a pair of arms extending downwardly from the stop plate between the rollers to be pivotally attached to a support member of the conveyor unit; the stop plate being pivotal from an elevated position above the rollers to a horizontal position along the unit edge; means for moving the stop plate between the elevated position and the horizontal position. Preferably, the means for moving the stop plate comprises a foldable linkage attached to a linear actuator, and wherein the linkage locks against pressure on the stop plate when the stop plate is in the elevated position.
Thus, it is an object of the present invention to provide an improved package sorting system and method.
It is another object of the present invention to provide a package sorting system and method in which sorting on one level does not require movement of a conveyor unit from one place to another.
It is another object of the present invention to provide a package sorting system and method with improved processing speed.
It is another object of the present invention to provide a package sorting system and method applicable to output packages to rows of vertically spaced receiving conveyors or chutes.
Other objects, features and advantages of the present inve
Cai Chunsheng
Huang Pao-Ter
Janik Jaroslav
Lecko John
Alston & Bird LLP
Bidwell James R.
United Parcel Services of America, Inc.
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