Bicycle Front Fork Vent Valve for Altitude Pressure Equalization
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Solution Overview
Problem
Existing front forks for bicycles experience undesirable changes in pressure-induced forces due to altitude and temperature variations, affecting the dynamics and performance of the suspension system, particularly in larger diameter telescoping tubes, and existing vent valves are difficult to access and prone to oil ejection.
Innovation Solution
The front fork design incorporates a vent valve positioned above the lower tube, allowing for easy access and reducing the risk of oil ejection, with a flow path connecting the sealed air volume in the lower tube to the valve at the top of the upper tube, enabling pressure equalization with atmospheric pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the vent valve is positioned in the lower tube, then pressure equalization is achieved, but the valve becomes difficult to access and prone to oil ejection
Solution Approach 1:
The vent valve is repositioned from the lower tube to the upper tube, changing the spatial dimension of valve location. This dimensional shift moves the valve to an accessible position at the top of the fork while maintaining pressure equalization functionality through the sealed interior region connection.
Solution Approach 2:
The sealed interior region acts as an intermediary pathway connecting the lower tube (where pressure equalization is needed) to the upper tube (where the valve is positioned for accessibility). This intermediary allows the valve to be remotely positioned without compromising its pressure regulation function.
2Ease of operation
If the valve is positioned at the top of the upper tube, then ease of access is improved, but the flow path complexity increases
Solution Approach 1:
The sealed interior region merges the spaces of the upper and lower tubes into a single pressurized volume. This merging eliminates the need for complex separate flow paths, allowing simple pressure equalization through the valve while maintaining a straightforward flow path despite the valve's remote position.
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 solution stabilizes the pressure in the sealed interior region, maintaining consistent suspension performance across varying altitudes and temperatures, and simplifies valve access and manufacturing, enhancing user convenience and reducing manufacturing complexity.
Implementation Method 1
a valve disposed in a flow path at or near a top end of the upper tube... when the valve is opened, pressure in the lower tube is equalized with atmospheric pressure
Data Source
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AI summary
Front forks for bicycles are described herein. An example front fork (200) includes a leg (204, 206) including an upper tube (210, 212) and a lower tube (214, 216). The upper tube (210, 212, 120, 2310) and the lower tube (214, 216) are configured in a telescopic arrangement. The upper tube (210, 212) and the lower tube (214, 216) define an interior region (312, 326) that is sealed and contains a volume of air in the lower tube (214, 216). The front fork (200) also includes a valve (384, 386) coupled to the upper tube (210, 212) at or near a top end of the upper tube (210, 212). A flow path is formed between the volume of air in the lower tube (214, 216) and the valve (384, 386) such that when the valve (384, 386) is opened, pressure in the lower tube (214, 216) is equalized with atmospheric pressure.