Bicycle Chain Outer Link Plate Chamfered Edge Design

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Solution Overview

Problem

Bicycle chains often interfere with the teeth of the outer chain ring during downshifting, leading to manufacturing complexities and potential weakening of the chain ring, as existing solutions require additional manufacturing steps and recesses or indentations that can compromise the chain ring's strength.

Innovation Solution

The design of a bicycle chain with modified outer link plates that minimize interference with the outer chain ring teeth during downshifting, featuring first and second end portions and a connecting portion, with specific edge configurations and chamfered edges to reduce contact and allow smooth movement, eliminating the need for downshifting recesses or indentations on the chain ring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If downshifting recesses or indentations are added to the inside surface of the large front chain ring, then the chain can downshift more effectively, but the manufacturing complexity increases and the chain ring strength decreases

Engineering Contradiction:
Improvedownshifting capabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Instead of modifying the chain ring to accommodate the chain during downshifting, the invention inverts the approach by modifying the chain's outer link plates to minimize interference with the chain ring teeth. The outer link plates are designed with reduced contact areas and specific geometric configurations that allow smooth downshifting without requiring any modifications to the chain ring, thereby eliminating additional manufacturing steps while maintaining downshifting effectiveness.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention applies local quality by specifically modifying only the outer link plates of the chain where they contact the chain ring teeth. The end portions and connecting portions of the outer link plates are given specific geometric configurations with controlled contact areas, while the rest of the chain structure remains unchanged. This localized modification achieves the downshifting improvement without affecting the overall chain design or requiring chain ring modifications.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If downshifting recesses or indentations are added to the inside surface of the large front chain ring, then the chain can downshift more effectively, but the chain ring strength is weakened

Engineering Contradiction:
Improvedownshifting capabilityVSAvoidchain ring strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The invention inverts the traditional approach by not modifying the chain ring at all. Instead, the outer link plates of the chain are designed with specific geometric configurations that minimize interference with the chain ring teeth during downshifting. This eliminates the need for weakening the chain ring through recesses or indentations, thereby maintaining full chain ring strength while achieving effective downshifting.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If the outer link plates are modified to minimize interference with chain ring teeth, then the manufacturing efficiency increases, but the chain design complexity increases

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidchain design complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention applies local quality by making specific geometric modifications only to the outer link plates where they contact the chain ring. The end portions and connecting portions are given precise configurations that control the contact area and interference patterns. These localized modifications can be integrated into existing chain manufacturing processes without requiring complete redesign of the entire chain, thereby maintaining manufacturing efficiency while achieving the desired performance improvement.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2339207B1Bicycle outer chain link plate
Publication Date: 2016.06.08 SHIMANO INC
  • EP2339207B1 patent drawingFigure 1
  • EP2339207B1 patent drawingFigure 2
  • EP2339207B1 patent drawingFigure 3~4

AI summary

An outer chain plate (31,32) is configured to aid in downshifting such that a chain moves more smoothly from an outer chain ring (sprocket) to an inner chain ring (sprocket) with either no downshifting recess being provided on the outer chain ring or at least a shallower than normal downshifting recess being provided on the outer chain ring. At least a bottom part of the outer chain plate that faces a center axis of a sprocket when in use has a portion removed to minimize contact with outer chain ring when downshifting. Preferably, the bottom part of the outer chain plate has a chamfered outer edge portion (55,56) along a cutout portion that defines a reduced area portion (41b,42b).