Wireless Front Derailleur Layout for Cable-Free Bicycle Shifting

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Solution Overview

Problem

Existing electromechanical gear changers for bicycles are bulky, heavy, expensive, difficult to install, and unattractive due to their wired communication and power supply, which also requires multiple cable lengths for different bike frame sizes.

Innovation Solution

A wireless electromechanical front gear changer for bicycles, featuring a base member, a linkage, a chain guide, a motor, a gear transmission, a CPU, and a power supply, with a receiver for wireless signals and a housing that allows wireless signal passage, making it lightweight, compact, and easy to install.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wired communication and power supply are used, then reliable power and signal transmission is achieved, but the system becomes bulky, heavy, and difficult to install

Engineering Contradiction:
Improvepower and signal transmission reliabilityVSAvoidcable management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the cable and connector components from the gear changer system. The housing is designed as a cable-free unit that attaches directly to the bicycle frame, eliminating the need for separate cable management and reducing installation complexity while maintaining functional reliability through integrated wireless communication and power transmission.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If multiple cable lengths are provided for different bike frame sizes, then adaptability to various frame sizes is achieved, but inventory complexity and cost increase

Engineering Contradiction:
Improvecompatibility with different bike frame sizesVSAvoidinventory management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs the housing as a universal component that can be attached to various bicycle frame sizes without requiring different cable lengths. The standardized attachment mechanism and integrated wireless system allow the same housing unit to function across multiple frame sizes, eliminating the need for maintaining multiple cable inventory variants.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If wireless communication is implemented, then installation ease and compactness are improved, but power supply and signal transmission reliability may be compromised

Engineering Contradiction:
Improveinstallation easeVSAvoidwireless signal transmission reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the mechanical cable-based power and signal transmission system with wireless communication technology. This substitution eliminates the physical cables and connectors, simplifying installation and reducing mechanical failure points while maintaining system reliability through robust wireless protocols and power transmission methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4257470B1Front gear changer
Publication Date: 2025.05.14 SRAM LLC
  • EP4257470B1 patent drawingFigure 1
  • EP4257470B1 patent drawingFigure 2A~2B
  • EP4257470B1 patent drawingFigure 3

AI summary

An electromechanical front gear changer for a bicycle is provided, the bicycle having a chain, including a base member attachable to the bicycle. A linkage is movably coupled to the base member. A chain guide is movably coupled to the linkage for contacting the chain. A motor is supported by the base member. A gear transmission is driven by the motor to move the linkage. A CPU is provided for controlling the motor and a power supply is supported by the base member to power the motor and the CPU.