Patent Application
20080152468
1. Field of the Invention
This invention relates to the field of container storage and more particularly to a system storage and retrieval of containers that efficiently utilizes space.
2. Description of the Related Art
Many storage systems have been devised to store and retrieve goods, usually in container or on palates. The simplest of such systems consists of storage bins, one deep, situated along aisle ways that are wide enough for a fork lift to maneuver and access containers or palates located in the bins. Even if a forklift is capable of turning within its own radius, the forklift requires room to maneuver as well as sufficient space for its own ingress and egress. Because the fork lift must turn to access and remove the container/palate, the aisle must be wider than the container/palate is deep. Therefore, in this configuration, more floor space is consumed by aisle ways than by storage bins. Some improvement to this storage system's efficiency can be derived from having more than one level of storage, but this is limited to the height of access for a fork lift.
One improvement to this lack of efficiency is proposed in U.S. Pat. Application No. 2004/0165974 to Gironi, et al. In this, a three dimensional array of storage bins are accessible by a “trans-elevator” that traverses aisle between stacked storage locations. Although this device permits a greater number of stacked cartons, it still has the inefficiency of aisles.
Another solution is proposed in U.S. Pat. Application No. 2004/0146380 to Baker, et al. In this, a system of conveyors pass through aisles formed between storage locations. Although this device permits a greater number of storage locations, it still has the inefficiency of aisles.
U.S. Pat. No. 3,730,358 to Oji has a random storage system that uses an overhead crane to shuffle containers until the desired container is accessible. This system requires extra storage space for all containers that need be moved while accessing the container below, spacing between the containers for crane access and headroom for the overhead crane system and therefore doesn't utilize space efficiently.
U.S. Pat. No. 3,622,020 to Sarvary has a mechanized palette storage system that uses elevators and trucks. This system has aisle ways and therefore doesn't utilize space efficiently.
What is needed is a system that will store palates or containers in a space-efficient manner while providing random access to any given palate or container.
In one embodiment, an efficient storage system is disclosed including containers having a top, bottom, walls and an access door. The containers are moveably organized within a building that organized as a grid of rows and columns, each row wider than the width of each of the containers and each column deeper than the depth of each of the containers. At least one empty position within the grid allows for shifting of the containers from one row/column to another. At least one access station is provided for loading and unloading the containers through the access doors and a mechanism is provided for moving the containers within the grid.
In another embodiment, a method of efficiently storing containers is disclosed. The containers have a top, bottom, walls and at least one access door. The method includes organizing the containers within a building on a grid. The containers are movable from one row and one column within the grid to a neighboring row and column within the grid and there is at least one empty location within the grid. A target container is selected (e.g., the container of which access is desired) and the containers within the grid are sequentially shifted until the target container reaches an access point.
In another embodiment, an efficient storage system is disclosed including a plurality of storage containers, each having a top, bottom, side walls and an access door organized in a grid of equal sized positions. The grid is organized in rows and columns, each position wider than the width of each of the containers and each position deeper than the depth of each of the containers. There is at least one more position than storage containers, allowing for shifting of the containers. At least one access station is provided for loading and unloading the containers through the access doors. The storage containers are mechanically moved within the grid.
The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:
Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures. The term container represents any storage unit that holds goods or other materials (e.g., nuclear rods, Petri dishes, etc). The container can be of any size depending upon the types of goods being stored. One example of such a container is the moving containers that some companies deliver to a customer's site for loading, and then retrieve them after loaded. Another example is the cargo containers used for shipping between countries, whereby the container is roughly the size of a tractor trailer and can be stacked onboard a ship for overseas shipment, then lifted off the ship and placed upon a flatbed truck for final delivery to a destination. Containers don't have to be large. Small containers are more practical for assembly components such as screws, washers, electronic components, etc. In all of the following, for simplicity, the description will refer to containers, though, palates or any other monolithic storage unit is fully interchangeable with container. For example, the present invention is useful for storing soda cans, whereby each can is one unit of storage and is manipulated just as a container is manipulated.
Although shown as equal sized containers, nothing precludes using multiple container sizes. For example, a system can have 4′×12′×8′ containers mixed with 4′×6′×8′ containers, whereby two 4′×6′×8′ containers occupy the space of one 4′×12′×8′ container.
Generally, there are locations in the world such as Japan, Florida and parts of California where the price of land or building floor space is very expensive. As a result, there have been attempts to efficiently utilize as much space as possible. For example, in Japan, parking lots have stacked parking spaces whereby a car elevator lifts the car to the second level.
For storage of containers, it would be ideal to completely occupy the entire floor of a building with containers. Furthermore, if a building is of open construction with a single floor, it would be ideal to utilize the maximum cubic space of that floor. If every container had the same content, this could be done, but most storage operations include containers of varying content. One example of such an operation is self-storage. In this, individuals are usually assigned a storage location and when they need to store or retrieve something from their storage location, they go to the location, open a door and access the contents. This system requires wide aisles between rows of storage locations for the customer to drive to their storage location. If, instead, the goods are stored in containers, the containers can be delivered to the customer when they require access, permitting more efficient storage of the containers. As described previously, prior attempts to provide container storage access all required aisles or wasted space. Such containers could not be stored by filling a building from the front to the back, because as soon as you fill the building, the customer with the storage container in the back will want access and all other containers in front of theirs will have to be relocated.
Referring to
To move the containers, scissor jacks 14 are positioned at the ends of every row and column. For a three by three configuration as shown in
Referring to
Referring now to
Next, in
Another way to represent this sequence is shown in Table-1 below:
In this sequence, 9 shift operations are required to move the container, “b” from the A2 position to the C3 position. If container “a” was desired, instead, the additional shifts shown in Table-2 would be required:
This sequence requires four additional shifts for a total of 13 shifts, this being the longest sequence for a 3 by 3 matrix. A four by four matrix would require 25 shift operations to move the furthest container to the access door, while a five by five matrix would require 32 shift operations for the worst case.
Basically, to move a given container one position requires four shift operations. Therefore, if the matrix is three by five (A1 . . . C5), eight (2*4) shift operations are required to move from the A1 to the C1 position and sixteen (4*4) shift operations are required to move from the C1 position to the C5 position. This can be represented mathematically as:
4*(X−1)+4*(Y−1)−3,
where X is the number of positions in the X direction or columns and Y is the number of positions in the Y direction or rows. Three is subtracted because on the last shift operation, the designated container is in position on the first shift.
For a ten by ten matrix, 4*(10−1)+4*(10−1)−3 (69) shift operations are required to access the most distant container, while if you assume a random access pattern, the average number of shifts to access a random container 20 within this matrix would be one half of that, or approximately 34 shift operations. These calculations assume only one access position located at a corner. Further improvements are possible by having multiple access position and centrally located access position.
It can be seen that, given a configuration as previously described, having multiple access doors will improve access time because the average number of shifts from any random location to any of the multiple access position will be less than the average number of shifts from any random location to a single access position. In this configuration, once the desired container 20 is positioned at one of the access positions, it can be accessed for loading and unloading, but if another user wants access to another container 20, they will have to wait until the first user is finished, in that an shifting to access the second user's container 20 will move the first user's container 20, unless, by luck, the second user's container 20 is already located at a second access position. This situation is addressed in embodiments having multiple empty positions such that the other containers 20 are rotated using the additional empty spaces while the first container 20 remains in its static position, allowing access to such.
Being that shift operations may require a substantial amount of time, various alternate embodiments are possible. The simplest alternative is to schedule access to each container. For example, a customer can request access to their container at a specific time of day, either by making an appointment by phone or over the internet.
Another way to reduce the access time is to use more space for empty locations. For example, consider the configuration is
Therefore, the average number of shifts for accessing any randomly selected container would be 6 instead of 11. The extra spaces help significantly in larger grids. For example, in the 10 by 10 grid, normally the worst case number of shifts required is 69. In this configuration, 99 spaces are occupied by containers results in a 99% efficient storage area. By adding one extra empty space, the worst case access reduces to 44 while only reducing the storage efficiency by an additional 1% to 98%. By adding three extra spaces, the worst case access reduces to 22 with an average access of 11 shifts with a storage efficiency of 96%.
As discussed above, in some embodiments, multiple access positions allow more than one user to access their containers 20. For instance, in the example of
Note that the above shifts require partial row/columns shifts and need mechanisms of the embodiments whereby a subset of the containers 20 of one row or one column can shift independently of other containers 20 in that row/column. For example, moving j,i left on column as above is done by mechanisms that shift the D2,D3 coordinates left one position without shifting the D4 position left, being that D4 contains the container 20 a being accessed by the first user.
It is anticipated that in some embodiments, an external door be provided at each access point to shield the users from coming into contact with the shifting containers 20.
Referring to
Also connected to the processor 110 is a system bus 130 for connecting to peripheral subsystems such as motor controls 140, sensor inputs 180, a graphics adapter 160 and a keyboard/mouse 170. The graphics adapter 160 receives commands and display information from the system bus 130 and generates a display image that is displayed on the display 165. The keyboard and mouse 170 are used to accept operator inputs for control of the system.
In general, the motor control 140 interfaces to the motor drive system 150. There are many known ways to control the motors that move the containers 20 around the grid, including servo motors and free running motors with feedback sensors. In many embodiments, sensors are positioned around the grid to sense, for example, the position of the containers 20 within the grid 16/18. The sensors 190 are connected to sensor input ports 180 and are any known type of sensor including electric eyes, micro-switches, proximity switches and the like.
The firmware 125 includes software algorithms that remember which container is in which position within the grid and, when requested, controls the motor system to shift the containers around the grid in order to move the target container to a target access location.
Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.
It is believed that the system and method of the present invention and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.
