Compactable Bicycle Frame Cable Routing and Chain Tension
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Solution Overview
Problem
Folding bicycles often compromise structural integrity and experience issues with chain tension and cable routing due to the movement of the rear wheel relative to the crank during folding and unfolding.
Innovation Solution
A compactable bicycle design that includes a frame with a steering structure and a rear wheel, a rear brake system with a brake cable that uses a biasing member to maintain tension and prevent tangling, and a derailleur system with biasing members to maintain chain tension in both use and storage positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the bicycle frame is folded to reduce storage volume, then the storage compactness is improved, but the structural integrity of the frame deteriorates
Solution Approach 1:
The frame is divided into multiple segments that can be folded relative to each other. The first frame portion and second frame portion are connected through a folding mechanism that allows compact storage while maintaining structural integrity through proper connection design.
Solution Approach 2:
The cable routing is pre-configured through cable guides positioned at specific locations on the frame portions. This preliminary arrangement ensures that cables are properly guided and tensioned during folding and unfolding operations, preventing cable damage and maintaining system integrity.
2Volume of moving object
If the rear wheel moves relative to the crank during folding, then the folding compactness is improved, but the chain tension and cable routing problems arise
Solution Approach 1:
Cable guides act as intermediary elements positioned on the frame portions to guide and control cable movement during folding. These guides ensure proper cable routing and maintain tension on the brake cable and derailleur cable, preventing tangling and mechanical issues.
Solution Approach 2:
The biasing members apply variable forces to maintain appropriate tension parameters on the brake cable and derailleur cable during folding and unfolding operations. This dynamic tension management ensures reliable cable routing and prevents mechanical problems.
3Ease of operation
If the brake cable is pulled through the cable guide during folding, then the cable management is improved, but the cable tangling and mechanical issues occur
Solution Approach 1:
The cable guide serves as an intermediary element that controls and guides the brake cable movement during folding operations. This prevents cable tangling and ensures smooth, reliable cable management throughout the folding and unfolding cycle.
Solution Approach 2:
The biasing member applies preliminary counteracting force to oppose cable tangling and maintain proper cable tension. This preventive action ensures the cable remains properly routed through the cable guide during folding, preventing mechanical issues before they occur.
4Volume of moving object
If the derailleur system is moved during folding, then the folding compactness is improved, but the chain tension is compromised
Solution Approach 1:
The derailleur base biasing member applies variable force to maintain appropriate chain tension parameters during folding and unfolding. This ensures the chain remains properly tensioned throughout the movement cycle, preventing mechanical issues and maintaining driving train reliability.
Solution Approach 2:
The biasing members act as intermediary elements that maintain chain tension during derailleur movement. These components ensure proper chain engagement and tension management, preventing chain drop and mechanical failures during folding 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 design enhances the structural integrity and riding experience of folding bicycles by maintaining proper chain tension and cable management in both use and storage positions, reducing the risk of mechanical issues.
Implementation Method 1
The brake cable biasing member is positioned to urge the first portion of the first segment of the rear brake cable back through the first cable guide
Implementation Method 2
movement of the derailleur arm relative to the derailleur base controls tension in the chain
Implementation Method 3
the derailleur base biasing member urges the derailleur base in a direction that applies tension to the chain when the first and second frame portions are in the folded position
Data Source
AI summary
In an aspect, a compactable bicycle is provided and includes a frame A first frame portion has a steering structure, which has a front wheel. The steering structure further includes a handlebar. A second frame portion has a rear wheel. In a use position the first and second frame portions are unfolded to an unfolded position. In a storage position the first and second frame portions are folded to a folded position, in which the front wheel and the rear wheel are next to each other. The front wheel has a front wheel connector and the rear wheel has a rear wheel connector that is releasably connectable to the front wheel connector to hold the front and rear wheels together.