Grid-Top Load Handling Layout for Dense Container Retrieval
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Solution Overview
Problem
Existing storage systems with robotic devices for handling stacked containers face inefficiencies due to the need for aisle space, limited height restrictions in enclosed spaces, and inefficiencies in selecting single containers from multi-product stacks.
Innovation Solution
The development of load handling devices that occupy substantially only a single grid space in the storage system, allowing lateral movement above the stacks and enabling efficient retrieval and movement of containers without obstructing other devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If load handling devices are designed with large footprints to accommodate lifting mechanisms, then lifting capability is improved, but the number of devices that can be accommodated in the storage system decreases
Solution Approach 1:
The lifting mechanism is repositioned from a horizontal arrangement (occupying lateral space) to a vertical arrangement (occupying vertical space above the container). The lifting device is moved to the rear of the vehicle, allowing the container receiving space to extend forward, thereby reducing the lateral footprint while maintaining lifting capability through vertical cable deployment.
Solution Approach 2:
The load handling device is divided into functionally independent modules: a compact vehicle module for lateral movement and a separate lifting mechanism with cables and winch. This segmentation allows the lifting components to be positioned vertically above the container receiving space rather than horizontally alongside it, reducing the overall footprint.
2Productivity
If multiple load handling devices are deployed to improve retrieval speed, then productivity increases, but device obstruction and coordination complexity increase
Solution Approach 1:
The storage system is divided into discrete grid spaces, with each load handling device assigned to a specific grid space. This spatial segmentation allows multiple devices to operate independently in different grid spaces without obstruction, enabling parallel operations that increase productivity while maintaining simple individual device control.
3Ease of operation
If load handling devices are positioned to access containers from the side, then container access is simplified, but aisle space is required reducing storage density
Solution Approach 1:
Instead of accessing containers from the side (horizontal access), the load handling device accesses containers from above (vertical access). The lifting mechanism deploys cables downward from the vehicle to engage container lifting points on the container tops, inverting the traditional access direction and eliminating the need for lateral aisle space.
Solution Approach 2:
Container access transitions from the horizontal dimension (side access requiring aisles) to the vertical dimension (top access from above). The load handling device positions itself laterally above the target container and lowers lifting cables vertically to engage the container, eliminating the need for horizontal aisle space while maintaining operational simplicity.
Data Source
AI summary
A storage system and a load handling device for lifting and moving containers stacked in the storage system are described. The storage system includes a plurality of rails or tracks arranged in a grid pattern above the stacks of containers. The grid pattern can include a plurality of grid spaces and each stack is located within a footprint of only a single grid space. The load handling device is configured to move laterally on the rails or tracks above the stacks. The load-handling device includes a container-receiving space located above the rails or tracks in use and a lifting device arranged to lift a container from a stack into the container-receiving space. The load handling device has a footprint that, in use, occupies only a single grid space in the storage system.