Stacked Container Retrieval Using Multi-Level Rail Handling
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Solution Overview
Problem
Existing storage systems with stacked containers face inefficiencies in accessing containers located in the middle or bottom of stacks due to the need for extensive 'digging' operations, which reduces productivity and increases costs due to the requirement of multiple handling devices and lengthy operation times.
Innovation Solution
A storage system employing a first handling device capable of lifting multiple non-target containers from a stack in a single operation, followed by a second device lifting the target container and moving it laterally, significantly reducing the number of lifting operations required to access a target container, thereby enhancing retrieval speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If containers are stacked in rows to improve storage density, then storage density is improved, but accessing containers in the middle or bottom of stacks becomes difficult and time-consuming
Solution Approach 1:
The system segments the stack access operation into two distinct phases: first, a multi-container lifting device removes multiple non-target containers from the top of the stack in a single operation; second, a single-container lifting device retrieves the target container. This segmentation eliminates the need for repeated single-container removal operations, significantly reducing access time while maintaining high storage density.
Solution Approach 2:
The system performs preliminary action by using the multi-container lifting device to clear non-target containers from the stack before the target container can be accessed. This preliminary removal operation prepares the stack for efficient target container retrieval, transforming a potentially time-consuming sequential access process into a streamlined two-stage operation.
2Ease of operation
If multiple handling devices are used to access containers at different stack levels, then container accessibility is improved, but device complexity and operational costs increase
Solution Approach 1:
The system divides the handling device fleet into two specialized types: multi-container lifting devices for bulk removal operations and single-container lifting devices for precise target container retrieval. This functional segmentation allows each device type to be optimized for its specific purpose, improving overall system efficiency without requiring a large number of general-purpose handling devices.
Solution Approach 2:
The multi-container lifting device serves multiple functions: it can remove varying numbers of non-target containers from different stack positions, clear entire stacks, and prepare stacks for subsequent target container retrieval. This multi-functionality reduces the need for specialized equipment for each operation type, simplifying the overall device architecture while maintaining high accessibility.
3Measurement precision
If single-container lifting operations are used for each container retrieval, then precision in container selection is improved, but productivity and retrieval speed decrease
Solution Approach 1:
The retrieval process is segmented into a bulk removal phase using multi-container lifting devices and a precise selection phase using single-container lifting devices. This segmentation allows the system to combine the speed advantages of bulk operations with the precision of individual container selection, achieving both high productivity and accurate container retrieval.
Solution Approach 2:
The system maintains continuity of useful action by seamlessly transitioning from multi-container removal to single-container retrieval within a coordinated operation. The multi-container lifting device continuously clears non-target containers while the single-container device is positioned and ready to immediately retrieve the target container, eliminating idle time and maintaining continuous productive action throughout the retrieval process.
Data Source
Figure 1~2
Figure 3(a)~3(c)
Figure 4
AI summary
A storage system comprises a frame (114) containing a plurality of stacks (112) of containers (110), a first track system (122) supported by the frame and comprising a lower set of rails, a second track system (422) comprising an upper set of rails arranged above the lower set of rails, a first load handling device (30) independently movable on the first track system (122) and capable of lifting a single container (110) from a stack and moving the container laterally, and a second load handling device (150) independently movable on the second track system (422) and capable of lifting a plurality of containers (110) in a single operation, wherein the second track system (422) is spaced from the top of the frame structure (114).