Bicycle Fork Suspension With Air Cushion to Prevent Bottoming Out
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Solution Overview
Problem
Conventional bicycle suspension systems often fail to fully absorb the impact of larger obstacles, leading to 'bottoming out' and force transmission to the rider, as they are tuned for smaller obstacles, and require complex valve arrangements for progressive damping, which increases cost and maintenance.
Innovation Solution
A suspension system incorporating a first and second tube with a gas-filled chamber, a barrier with one-way valves, and an adjustable blocker to control gas flow, providing progressive resistance and energy absorption near full compression, allowing for adjustable damping and reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suspension is tuned to absorb small obstacles, then it performs well on typical terrain, but it fails to absorb large obstacles and bottoms out
Solution Approach 1:
The suspension system dynamically adjusts its damping characteristics through a progressive resistance mechanism. As compression increases, the air cushion volume decreases, increasing resistance progressively. This allows the same suspension to handle both small obstacles (softer initial response) and large obstacles (stiffer progressive response), preventing bottoming out while maintaining comfort on typical terrain.
Solution Approach 2:
The system changes the physical parameters of the air cushion during operation. As the barrier moves during compression, the volume and pressure of the trapped air change dynamically. This parameter change creates progressive resistance that increases with compression depth, allowing the suspension to adapt to varying obstacle sizes without bottoming out.
2Force
If complex valve arrangements are used to achieve progressive damping, then compression resistance improves, but cost increases
Solution Approach 1:
The invention uses pneumatic principles with a simple air cushion and barrier arrangement to achieve progressive damping. Instead of complex mechanical valve arrangements, the system relies on the compressible nature of air and the changing volume/pressure dynamics as the barrier moves. This provides progressive compression resistance through fundamental pneumatic physics rather than complicated valve mechanisms.
Solution Approach 2:
The air cushion system is self-regulating and requires no active control or complex valve arrangements. As compression occurs, the air pressure automatically increases in proportion to the compression depth, providing progressive resistance without external intervention. The system serves itself through the inherent properties of compressed gas.
3Force
If incompressible fluid is used for damping, then damping control is achieved, but serviceability decreases
Solution Approach 1:
The system uses compressible air instead of incompressible hydraulic fluid. This pneumatic approach provides adequate damping force while dramatically improving serviceability. Air can be easily replenished or replaced without complex fluid handling, and the system can be serviced more conveniently in the field compared to oil-filled hydraulic systems.
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 absorbs impact by controlling gas flow to resist compression, reducing the likelihood of 'bottoming out' and allowing for customizable damping, enhancing rider comfort and system durability.
Implementation Method 1
a first chamber substantially filled with a gas... Upon a compression stroke, movement of the barrier within the first tube may move at least some of the gas from the first chamber through the orifice... into the second chamber
Implementation Method 2
The barrier may include the first substantially one-way valve, which valve may allow the gas to flow from the second chamber to the first chamber
Data Source
AI summary
A front fork of a bicycle may include a suspension system that includes a damper. The damper may include a hollow tube with orifices that may be partially blocked by an adjustable blocker. A free end of the adjuster that adjusts the blocker may maintain its axial position in any rotational position. Ambient air may be introduced through a valve and retained in the suspension system. The suspension may include a mechanical spring in a chamber away from the valve that introduces the ambient air.