STS Multi-Trolley Portal Gantry Crane Design
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Solution Overview
Problem
Conventional container cranes are inefficient in loading/unloading large container vessels due to high trolley travel times, noise, maintenance costs, sway issues, and poor aerodynamic performance, which limits their capacity to operate in high winds and requires costly foundation works.
Innovation Solution
A portal gantry crane with two parallel main girders and legs positioned in a midplane, allowing independent operation of trolleys on both sides of the ship, reducing trolley travel distance, and featuring a superior aerodynamic design with prestressed girders and self-propelled trolleys for reduced noise and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the trolley travels at high speed to reduce travel time, then productivity is improved, but noise and wear increase resulting in higher maintenance costs
Solution Approach 1:
The crane is divided into two independent trolleys operating on separate girders, allowing parallel operations. Each trolley serves a specific bay area, eliminating the need for one trolley to traverse the entire ship width. This segmentation enables both trolleys to operate at lower speeds while maintaining high productivity through simultaneous container handling.
2Adaptability or versatility
If the trolley uses long ropes to reach containers farthest to the quay, then versatility is improved, but sway increases due to rope length and elasticity
Solution Approach 1:
The patent transitions from a single horizontal beam to a three-dimensional structure with two elevated girders positioned above the quay. This vertical dimensionality change allows trolleys to be located closer to the ship while maintaining full container reach capability, thereby reducing rope lengths and minimizing sway without compromising versatility.
3Adaptability or versatility
If the crane uses a cantilever structure to extend the beam, then functionality is improved, but foundation costs increase due to unequal weight distribution
Solution Approach 1:
The patent employs an asymmetric structural arrangement where two girders are positioned at different distances from the quay edge. This asymmetric configuration, combined with the midplane leg positioning, creates a balanced weight distribution that reduces foundation requirements while maintaining the necessary beam extension capability for reaching containers.
4Device complexity
If a single trolley serves the entire ship width, then device complexity is reduced, but productivity decreases due to long travel time
Solution Approach 1:
The crane system is segmented into two independent trolleys, each responsible for specific bay areas. This segmentation doubles the container handling capacity by enabling parallel operations, significantly improving productivity. The increased device complexity is offset by the substantial gain in operational efficiency and the ability to handle Ultra Large Container Vessels effectively.
Data Source
Figure 1~2
Figure 3~11
Figure 8~9
AI summary
Portal gantry crane comprising: - Two parallel main girders (11) running side by side on respective sides of a midplane (M), - two legs (20, 21) each positioned in said midplane (M), - two couples of trolleys (40), each couple of trolleys operating on a corresponding girder (11), each trolley carrying a hoist.