Wireless Front Gear Changer With Four-Bar Linkage and Low Drag

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Solution Overview

Problem

Existing electromechanical bicycle gear changers are bulky, heavy, expensive, and difficult to install due to their wired communication and power requirements, necessitating the production of various cable lengths for different bike frame sizes.

Innovation Solution

A wireless electromechanical front gear changer with a compact design, featuring a removable battery and a four-bar linkage mechanism, which includes a four-bar linkage, a motor gearbox module, and a wireless communication system for easy installation and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wired communication and power systems are used in electromechanical gear changers, then reliable power supply and communication are achieved, but the device becomes bulky, heavy, and difficult to install

Engineering Contradiction:

Improvepower supply reliabilityVSAvoidgear changer weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces wired mechanical/electrical connections with wireless communication technology. The gear changer uses wireless communication modules to receive shift commands and transmit status information, eliminating the need for heavy cables and connectors while maintaining reliable communication between the shifter and the gear changer unit.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If wired communication and power systems are used in electromechanical gear changers, then reliable power supply and communication are achieved, but the device becomes bulky and difficult to install

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidinstallation ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If traditional electromechanical gear changer design is used, then gear shifting function is achieved, but aerodynamic drag increases

Engineering Contradiction:

Improvegear shifting functionVSAvoidaerodynamic drag

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent repositions the gear changer unit from a traditional front-mounted location to a rear-mounted location on the bicycle frame. This dimensional relocation places the mechanism in a region with lower aerodynamic impact, reducing drag while maintaining the gear shifting function through the wireless control system.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12523277B2Front gear changer

Publication Date: 2026.01.13 SRAM LLC

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. A manually operated device is disposed on the electromechanical front gear changer.