Stacker Crane Layout for Dual-End Rack Placement
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Solution Overview
Problem
Existing stockers face a limitation in housing capacity due to interference between cranes and the stocker casing, reducing the number of articles that can be stored, as the mast obstructs transfer units at one end, preventing rack placement.
Innovation Solution
A stocker design with cranes capable of raising and lowering along orthogonal mast surfaces, allowing racks to be positioned at both ends, and incorporating an entry area for crane operation without collision, with a controller managing crane travel to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transfer unit is provided on one surface of the mast, then the structure is simplified, but the number of articles that can be housed is reduced due to space loss at one end
Solution Approach 1:
The transfer unit is moved from a single-surface configuration to a dual-surface configuration, utilizing both surfaces of the mast. This dimensional expansion allows racks to be positioned at both ends of the stocker, effectively doubling the usable storage capacity while maintaining the same physical footprint.
Solution Approach 2:
The two cranes are configured with asymmetric orientations where each crane's transfer unit faces the opposite direction. This asymmetric arrangement allows both cranes to access racks at different ends of the stocker simultaneously, eliminating the space loss problem of single-surface configurations.
2Quantity of substance
If racks are positioned at both ends of the stocker, then the number of articles housed increases, but crane collision risk increases in the entry area
Solution Approach 1:
The control device monitors the positions of both cranes in real-time and dynamically adjusts their movement to prevent collision. When one crane is in the entry area, the control device restricts or guides the movement of the other crane, providing continuous feedback-based position management to ensure safe operation while maintaining high utilization of storage space.
3Ease of operation
If the mast is positioned to allow transfer unit access, then article transfer is enabled, but the mast interferes with the stocker casing at one end
Solution Approach 1:
By providing transfer units on both surfaces of the mast, the system eliminates the dead zone created by single-surface configurations. The mast can now serve both ends of the stocker, converting previously unusable space into productive storage area.
Solution Approach 2:
Instead of having the transfer unit face one direction, the system inverts the approach by having transfer units face opposite directions on both surfaces of the mast. This allows the mast to be optimally positioned for access from both ends without interfering with the stocker casing.
Data Source
AI summary
A stocker includes a first stacker crane and a second stacker crane each including a mast having a pair of surfaces orthogonal to a traveling direction and a transfer unit provided to be capable of being raised and lowered along one of the pair of surfaces and configured to transfer an article to and from a first rack and a second rack. The two cranes are disposed such that each face a direction opposite to a direction in which the one of the pair of surfaces on which the transfer unit is provided to be capable of being raised and lowered face each other in the traveling direction. A first space is provided with an entry area that the two cranes mutually enter. A controller controls traveling of the two cranes such that the two cranes do not collide with each other.