Bicycle Derailleur Control Device Single Lever Indexing
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Solution Overview
Problem
Existing bicycle derailleur control devices are cumbersome and inefficient, requiring multiple levers or buttons for gear shifting, which can be confusing and difficult to manage, especially for cyclists needing to shift gears quickly and smoothly.
Innovation Solution
A control device with a single manual actuation lever and an indexer mechanism featuring a toothed wheel with slanting teeth and pawls that allows for precise angular control of the cable-winding bush, enabling smooth and efficient gear shifting between toothed wheels with a single lever movement, either up or down, by engaging and disengaging the pawls with the teeth at specific thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple levers or buttons are used for gear shifting, then the gear shifting function can be achieved, but the device becomes cumbersome and difficult to manage
Solution Approach 1:
The patent combines multiple control functions (gear shifting up and down) into a single lever mechanism. The lever integrates both upward and downward gear shifting capabilities through its rotation range, eliminating the need for separate levers or buttons for each function. This merging of functions directly reduces device complexity while maintaining ease of operation.
Solution Approach 2:
The single lever is designed to perform multiple functions: it can shift gears upward, shift gears downward, and is integrated with the brake lever system. This multi-functional design allows one component to replace what would traditionally require multiple separate controls, thereby simplifying the overall device while preserving comprehensive gear shifting capability.
2Device complexity
If a single lever is used for gear shifting, then the device complexity is reduced, but precise angular control of the cable-winding bush is required
Solution Approach 1:
The patent introduces an intermediary indexing mechanism between the single lever and the cable-winding bush. This intermediary system includes a toothed wheel with indexed teeth and a pawl that engages with the teeth to provide precise angular positioning. The intermediary mechanism translates the simple rotational motion of the lever into precise, controlled angular displacement of the cable-winding bush, thereby achieving measurement precision without increasing overall device complexity.
Solution Approach 2:
The patent replaces complex mechanical control systems with a simplified lever mechanism combined with an indexing mechanism. Instead of using multiple levers or buttons with complex linkages, the invention uses a single lever whose rotation is converted into precise angular control through the toothed wheel and pawl indexing system. This substitution achieves precise control with fewer components.
3Productivity
If the lever is moved beyond a predetermined rotation threshold, then upward gear shifting is achieved, but the pawl must be brought into thrusting engagement with the teeth
Solution Approach 1:
The patent employs preliminary action through the predetermined rotation threshold and the pre-positioned pawl. As the lever rotates, the pawl is预先 positioned to engage with the toothed wheel at specific angular positions. When the lever reaches the predetermined threshold, the pawl automatically engages with the teeth to lock the gear shift position. This preliminary positioning and automatic engagement enables rapid gear shifting without requiring additional complex control mechanisms.
Solution Approach 2:
The indexing mechanism is designed to be self-regulating through the interaction between the lever, pawl, and toothed wheel. As the lever rotates, the pawl automatically engages with the teeth at the appropriate moment based on the predetermined geometry. The system self-manages the engagement and disengagement of the pawl without requiring external control, thereby achieving high-speed gear shifting while keeping the mechanism relatively simple.
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
This solution simplifies gear shifting by allowing seamless transitions between gears using a single lever, reducing complexity and enhancing the cyclist's ability to quickly change gear ratios, improving the overall efficiency and ease of use of the bicycle's gear system.
Implementation Method 1
a first pawl integral with a driven arm of the lever and brought into thrusting engagement on the first teeth while the lever is manually moved in a first direction beyond a predetermined rotation threshold
Implementation Method 2
a second pawl driven out of retention engagement with the second teeth by the driven arm of the lever while the lever is manually moved in the first direction up to the predetermined rotation threshold
Data Source
AI summary
A control device for a derailleur of a bicycle is described, comprising a support body, a cable-winding bush supported for rotation with respect to the support body, an indexer mechanism housed in the support body and suitable for controlling the angular position of the cable-winding bush, and a single manual actuation lever, the indexer mechanism comprising a toothed wheel integral in rotation with the cable-winding bush and having a first and a second plurality of slanting teeth, a first pawl integral with a driven arm of the lever and brought into thrusting engagement upon the first teeth while the lever is manually moved in a first direction beyond a predetermined rotation threshold, and a second pawl driven out of retention engagement with the second teeth by the driven arm of the lever while the lever is manually moved in the first direction up to the predetermined rotation threshold.