Tower Crane Wind Catching System for Weathervaning
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Solution Overview
Problem
Existing tower cranes with luffing jibs face challenges in efficiently orienting themselves in strong winds due to reduced slewing torque, making it difficult to deploy an adjustable wind handling system that increases wind pressure without adding complexity, weight, and increasing installation costs.
Innovation Solution
A lightweight, inexpensive wind handling system that automatically deploys a larger wind surface area when the boom is raised by exploiting its own weight, eliminating the need for a drive mechanism and maintaining crane performance by changing conformation under gravity, providing a reduced wind surface in service configuration and an extended surface in safety configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a drive mechanism is used to deploy sails on the boom, then the wind surface area is increased to improve weathervaning, but the device complexity and installation cost increase
Solution Approach 1:
The wind-catching system is designed to deploy automatically using its own weight when the boom is raised, eliminating the need for an external drive mechanism. The system serves itself by converting gravitational potential energy into the deployment action, thereby reducing device complexity and installation costs while still achieving the required wind surface area expansion for effective weathervaning
Solution Approach 2:
The system exploits the change in gravitational potential energy as the boom moves between lowered and raised positions. By designing the wind-catching system's center of gravity and mounting configuration, the system automatically transitions between deployed and retracted states based on the boom's angular position, achieving equipotential operation where gravity alone drives the deployment without additional mechanical complexity
2Area of moving object
If a drive mechanism is installed on the boom, then the wind surface area is increased, but the boom weight increases and load curve is penalized
Solution Approach 1:
The wind-catching system uses its own weight as the driving force for deployment, converting gravitational potential energy into mechanical work. This eliminates the need for additional motors, actuators, or power transmission components that would add dead weight to the boom, thereby maintaining the boom's load-carrying capacity and performance characteristics
Solution Approach 2:
The system changes its configuration parameter (surface area) based on the boom's angular position parameter. When the boom is raised to the safety configuration, the wind-catching system automatically transitions to a deployed state with maximum surface area. When the boom is lowered for service configuration, the system automatically retracts to minimize surface area, thereby adapting the wind surface parameter to the operational requirements without adding permanent weight
3Length of moving object
If the boom is raised to minimize turning radius, then the wind surface area is reduced, but the slewing torque from wind force is insufficient for effective weathervaning
Solution Approach 1:
The invention adds a new dimension to the wind-catching system by incorporating movable sail elements that can change their deployment state independently of the boom's angular position. This creates a decoupling between the turning radius (determined by boom angle) and the wind surface area (controlled by sail deployment), allowing both parameters to be optimized simultaneously for their respective functions
Solution Approach 2:
The wind-catching system transitions from a static structure to a dynamic one with movable sail elements that automatically adjust their deployment based on the boom's position. This dynamic adaptation allows the system to provide maximum wind surface area when the boom is raised for weathervaning, thereby generating sufficient slewing torque despite the reduced turning radius, while maintaining a compact profile during service operations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively aligns the crane with the wind direction while minimizing weight addition, simplifying installation, and maintaining high crane performance by naturally deploying a maximum wind surface in safety configuration and a minimum surface in service configuration.
Implementation Method 1
the windage system is configured to pass from the retracted conformation to the deployed conformation under the effect of its own weight alone when the boom is raised
Data Source
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AI summary
Tower crane comprising a tower on which is pivotally mounted a boom (1) movable in elevation and in lowering between a lowered position and a raised position, said crane being configurable between a service configuration in which the boom is controlled in rotation and a safety configuration in which the boom is in a raised position and is released in rotation on the tower to be able to orient itself in the direction of the wind, where a wind-catching system (2) is mounted on the boom and adjustable between a retracted conformation used in the service configuration to provide a reduced surface exposed to the wind, and a deployed conformation used in the safety configuration to provide an extended surface exposed to the wind, where this wind-catching system is configured to pass from the retracted conformation to the deployed conformation under the effect of its own weight alone when the boom is raised.