Bicycle Rear Derailleur with Blocking Device for B Gap Adjustment
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Solution Overview
Problem
Conventional rear derailleurs face challenges with precise B gap adjustment, particularly in bicycles with rear wheel suspension, where the geometry changes during deflection, requiring adjustments in the sag position, which is complex and often requires two people or specialized tools.
Innovation Solution
A rear derailleur design featuring a base element and a movable element coupled by a pivot mechanism, with a blocking device that securely tempers the pivot mechanism relative to the base element or movable element in predetermined blocking positions, allowing for precise adjustment and assembly without external tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional adjustment methods are used for B gap, then adjustment can be performed, but the process is complex and requires two people or specialized tools
Solution Approach 1:
The derailleur is pre-adjusted at the factory to a reference B gap value, eliminating the need for complex field adjustments. The blocking device is also pre-configured to enable simple field adjustments if needed, combining factory precision with user-friendly adaptability.
Solution Approach 2:
The blocking device enables the derailleur to be self-adjusting in the field. By blocking the pivot mechanism at predetermined positions, the system allows single-person adjustment without requiring specialized tools or a second person to hold components.
2Measurement precision
If derailleur is adjusted in sag position for suspension bicycles, then correct B gap is achieved, but the process requires loading the suspension and specialized tools
Solution Approach 1:
The derailleur is pre-adjusted at the factory to account for suspension deflection effects. The blocking device is pre-positioned to maintain the correct B gap regardless of suspension state, eliminating the need for complex sag-position adjustments in the field.
Solution Approach 2:
The blocking device creates adjustment positions that are universally applicable across different bicycle types (hardtail and full suspension). The same blocking positions work regardless of suspension state, making the adjustment process universally simple for all bicycle categories.
3Reliability
If blocking device is integrated directly on pivot mechanism, then secure temporary blocking is achieved, but the structure becomes more complex
Solution Approach 1:
The blocking device is merged with existing derailleur components (pivot mechanism, cage, or base element) rather than being a separate addition. This integration provides secure blocking functionality while minimizing increases in overall structural complexity.
Solution Approach 2:
The blocking device serves multiple functions: it provides secure temporary blocking, defines predetermined adjustment positions, and works across different bicycle types. This multi-functionality justifies the added complexity by delivering multiple benefits from a single integrated component.
Data Source
AI summary
The invention relates to a rear derailleur for a bicycle gearing system comprising: a base element which can be fitted to a bicycle frame; and a movable element which is coupled to the base element by a pivot mechanism and which can be displaced relative thereto in a pivotably movable manner, wherein the pivot mechanism is pivotably movable both relative to the movable element and relative to the base element. The rear derailleur comprises for easier adjustment of the chain tension a blocking device which is configured to at least temporarily secure the movable element relative to the base element, wherein the blocking device is configured in such a manner that the pivot mechanism can be temporarily secured by a direct coupling relative to the base element or relative to the movable element in at least one predetermined blocking position.