Filler Cap Tether with Load-Sensitive Disengagement Mechanism
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Solution Overview
Problem
Conventional filler cap tethers fail to reliably prevent the filler cap from being rotated open due to deformation or removal of the vehicle body-side corresponding portion, such as during a rear-end car accident, leading to potential loss or misplacement of the cap.
Innovation Solution
A filler cap tether with attachment portions on both ends, featuring a disengagement portion that allows the tether to disconnect when a predetermined load is applied, preventing the cap from being rotated open. This includes a circular body connected to the cap and a string-like member with engaging and disengagement mechanisms, such as a slit and tube structure, to manage forces and ensure the cap remains secure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional filler cap tether is used to prevent cap loss, then the cap can be retained after removal, but the cap may still be rotated open due to deformation or removal of the vehicle body-side corresponding portion during accidents
Solution Approach 1:
The tether is segmented into a cap-connected portion and a vehicle body-side portion that can separate under accident conditions. The detachment portion allows the tether to break at a predetermined location, separating the cap retention function from the vehicle body connection when subjected to excessive force during rear-end collisions or similar accidents.
Solution Approach 2:
The harmful effect of the tether transmitting accident forces to the cap is eliminated by extracting the connection point from the vehicle body-side corresponding portion. The detachment portion is designed to fail first, removing the force transmission path that would otherwise rotate the cap open during accidents.
2Strength
If the tether is made strong to prevent cap rotation, then cap security is improved, but the tether may cause additional damage during accidents by transmitting excessive forces
Solution Approach 1:
The tether is designed with a predetermined weak point that acts as a safety mechanism before excessive forces can be transmitted. The detachment portion is engineered to fail at a specific load threshold, cushioning the system by preventing force transmission to the cap while still providing normal retention function under regular conditions.
Solution Approach 2:
The potential harmful effect of a strong tether transmitting accident forces is converted into a beneficial safety feature. The detachment portion's designed weakness becomes a protective element that sacrifices itself to prevent greater harm to the cap and surrounding components during accidents.
3Ease of manufacture
If a simple tether structure is used, then manufacturing cost is reduced, but the tether cannot reliably distinguish between normal removal forces and accident forces
Solution Approach 1:
The tether is divided into segments with different structural properties - a stronger cap-connected portion and a weaker detachment portion. This segmentation allows the system to discriminate between normal forces (which the stronger portion handles) and accident forces (which cause the weaker portion to fail), achieving reliable force discrimination through simple structural differentiation rather than complex sensing mechanisms.
Data Source
AI summary
A filler cap tether includes attachment portions on both ends of a string-like member, of which one end-side attachment portion is connected to a filler cap to be removably mounted on an oil feeding port whereas the other end-side attachment portion is connected to the vehicle body-side corresponding portion. The filler cap tether includes a disengagement portion for permitting the filler cap and the vehicle body-side corresponding portion to enter into a disconnected state when a load with a predetermined value or above is applied.