Bicycle Derailleur Chain Guide Locking Mechanism
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Solution Overview
Problem
Bicycle derailleurs face issues with chain slack during rough riding due to the chain guide rotating counterclockwise, leading to undesirable slack, which existing motion resisting structures do not adequately address.
Innovation Solution
A bicycle derailleur with a linkage mechanism, a position-fixing member, and a locking mechanism that includes a motor-actuated cable reel and locking shaft to selectively fix the chain guide's position relative to the movable member, ensuring the chain remains taut by engaging the chain guide in specific angular positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-biased chain guide is used to take up chain slack, then the chain guide can rotate clockwise to take up slack when the chain engages smaller-diameter sprockets, but during rough riding bumps and shocks may cause the chain guide to rotate counterclockwise creating undesirable slack
Solution Approach 1:
The patent applies preliminary anti-action by using a biasing element to pre-bias the chain guide in a clockwise direction, creating a predetermined resistance against counterclockwise rotation caused by bumps and shocks during rough riding. This preliminary biasing force prevents the chain guide from rotating counterclockwise and creating undesirable chain slack before the harmful effect occurs.
Solution Approach 2:
The patent applies dynamics by making the chain guide rotatably mounted to the movable member, allowing it to dynamically rotate in response to chain tension variations while maintaining overall system stability. The chain guide can rotate clockwise to take up slack when needed, but the biasing element ensures it returns to or remains near its biased position, preventing excessive counterclockwise rotation during rough riding.
2Reliability
If motion resisting structures are added to prevent chain guide rotation in the opposite direction, then chain slack is reduced, but the device complexity increases
Solution Approach 1:
The patent merges the motion resisting function with the existing spring-biased chain guide structure by integrating a biasing element that provides clockwise biasing force. This combines the chain slack take-up function and the motion resistance function into a single integrated system, avoiding the need for separate complex motion resisting structures while achieving both objectives.
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 effectively prevents chain slack during riding by securely fixing the chain guide's position, maintaining chain tension and improving ride stability even under rough conditions.
Implementation Method 1
a biasing element biases the chain guide in a selected rotational direction around the rotational axis
Implementation Method 2
A position-fixing member selectively fixes a position of the movable member relative to the chain guide
Data Source
AI summary
A bicycle derailleur comprises a base member adapted to be mounted to a bicycle, a movable member, a linkage mechanism coupled between the base member and the movable member so that the movable member moves relative to the base member, and a chain guide coupled to the movable member for movement relative to the movable member. A position-fixing member selectively fixes a position of the movable member relative to the chain guide.