Bicycle Derailleur Mount for Rear Suspension Alignment

Solution Overview

Problem

The vertical movement of the rear wheel in bicycles with rear suspension causes the drive chain to move relative to the front derailleur, disrupting its shifting performance.

Innovation Solution

A derailleur mount system that includes a first mounting portion concentric with the pivot axis, a second mounting portion secured laterally to the rear frame, and a support portion to stabilize the front derailleur, allowing it to pivot with the rear frame while maintaining alignment with the chain guide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the front derailleur is mounted to the seat tube, then the mounting structure is simple, but the vertical movement of the rear wheel causes the chain to move relative to the front derailleur, disrupting shifting performance

Engineering Contradiction:

Improvemounting structureVSAvoidshifting performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The mounting structure is divided into separate components: a mount plate attached to the seat tube, a derailleur mount plate attached to the rear frame, and a support portion connecting them. This segmentation allows the front derailleur to be decoupled from the seat tube and mounted on the rear frame instead, eliminating the chain movement issue while maintaining structural simplicity through modular assembly

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The support portion acts as an intermediary element between the rear frame and the front derailleur mount. It provides a stable connection that allows the front derailleur to pivot with the rear frame while maintaining proper alignment with the chain guide, thus resolving the relative movement problem without requiring complex mounting mechanisms

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the front derailleur is mounted on the rear frame, then the chain alignment is maintained during rear wheel movement, but the mounting structure becomes more complex

Engineering Contradiction:

Improveshifting performanceVSAvoidmounting structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The mounting structure is divided into separate components: a mount plate attached to the seat tube, a derailleur mount plate attached to the rear frame, and a support portion connecting them. This segmentation allows the front derailleur to be decoupled from the seat tube and mounted on the rear frame instead, eliminating the chain movement issue while maintaining structural simplicity through modular assembly

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The support portion serves multiple functions: it connects the rear frame to the front derailleur mount, provides structural support, enables pivotal movement of the rear frame, and maintains alignment between the chain guide and front derailleur. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in overall structural complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8770608B1Bicycle front derailleur mount

Publication Date: 2014.07.08 SPECIALIZED BICYCLE COMPONENTS INC

AI summary

A bicycle including a bicycle frame that has a main frame and a rear frame coupled to the main frame for pivotal movement about a pivot axis, and a derailleur mount that is coupled to the bicycle frame. The derailleur mount has a first mounting portion that is concentric with the pivot axis and defining a plane, a second mounting portion that is secured to the rear frame at a location spaced laterally from the plane, and a support portion. A derailleur is attached to the support portion.