Umbrella Anti-Inversion Mechanism Floating Joint
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Solution Overview
Problem
Traditional umbrellas are prone to inversion in strong winds due to insufficient airflow through canopy apertures and unreliable string connections, which can lead to rib breakage and render the umbrella unusable.
Innovation Solution
The design incorporates an anti-inversion mechanism featuring a carbon fiber anti-inversion strut and floating joint system that prevents rib inversion by coupling the strut to the rib assembly, using a sliding joint and stop to maintain the rib's position, ensuring it does not bend upward under wind pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If apertures are placed in the canopy to allow airflow, then wind force is reduced, but the apertures are not large enough to provide sufficient airflow to prevent inversion
Solution Approach 1:
An anti-inversion string acts as an intermediary element connecting the canopy to the rib assembly. This string mediates the force transmission between the canopy and rib structure, providing additional support to prevent inversion when wind forces exceed what the aperture airflow reduction can handle alone.
Solution Approach 2:
The anti-inversion string is pre-installed and tensioned between the canopy and rib assembly before use. This preliminary configuration ensures that when wind pressure builds up, the string is already in position to counteract inversion forces immediately, rather than requiring reactive measures.
2Reliability
If strings are added to connect from the umbrella strut to the tip area, then inversion resistance is improved, but the strings can become loose, get cut or tangle over time
Solution Approach 1:
The anti-inversion string is designed to be self-adjusting through a floating joint mechanism. When the rib assembly moves or deforms under wind load, the floating joint allows the string to automatically reposition and maintain tension without becoming loose or tangled, eliminating the need for manual adjustment during use.
Solution Approach 2:
The connection system transitions from a static fixed string to a dynamic floating joint configuration. This allows the anti-inversion string to move and adapt its position relative to the rib assembly, maintaining effectiveness throughout the operational life of the umbrella even under varying wind conditions.
3Reliability
If the rib assembly is made stronger to withstand wind forces, then inversion resistance is improved, but the device complexity and weight increase
Solution Approach 1:
The anti-inversion string functions as a counterbalancing element that applies opposing force to wind-induced inversion pressures on the rib assembly. This allows the rib structure itself to remain relatively lightweight while still achieving high inversion resistance through the combined effect of the string's counteracting force.
Solution Approach 2:
The solution combines different material properties and structural elements - the flexible canopy fabric, the rigid rib assembly, and the tensile anti-inversion string - into a composite system where each component contributes its strengths to achieve overall inversion resistance without requiring any single component to be excessively strong or complex.
Data Source
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AI summary
An umbrella has a plurality of ribs attached to a runner by main struts. The umbrella has an anti-inversion mechanism formed of a plurality of anti-inversion struts. Each anti-inversion strut is pivotally coupled to one respective main strut and is pivotally connected to a floating joint member that is freely movable along a length of one respective rib. The anti-inversion mechanism also includes a stop that is fixedly attached to the rib and restricts the degree of travel of the floating joint member along the rib and is positioned to prevent the respective rib from inverting in response to an applied force.