Folding Bicycle Crank Positioning for Compact Stability

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Solution Overview

Problem

Existing folding two-wheeled bicycles often require tools, complex mechanisms, or multiple steps to fold, and they may not remain stable when folded, making them difficult to store and transport efficiently.

Innovation Solution

A folding bicycle design where the cranks and most of the seat post are positioned between the wheels in the folded state, allowing for easy folding without tools and maintaining stability, with a focus on compactness and ease of use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional folding mechanisms are used, then the bicycle can be folded, but the folding process requires tools, complex mechanisms, or multiple steps

Engineering Contradiction:
Improveease of foldingVSAvoidfolding mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The bicycle frame is divided into multiple foldable sections (head tube assembly, seat tube assembly, down tube assembly) that can be independently folded and positioned. This segmentation allows each section to be simplified and folded without requiring complex overall mechanisms or tools.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using complex locking mechanisms to hold the folded position, the invention uses gravity and the positioning of components (cranks and seat post between wheels) to naturally maintain the folded state. The folded position becomes the stable state through inverted design logic.

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

2Volume of moving object

If the bicycle is folded compactly, then storage space is reduced, but the bicycle may roll away and become unstable

Engineering Contradiction:
Improvefolded volumeVSAvoidfolded stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The cranks and seat post are positioned between the wheels in the folded state, merging multiple components into the compact space between the wheels. This arrangement achieves compact folded volume while the interlocking position of these components provides inherent stability and prevents rolling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bicycle structure itself provides stability through the positioning of cranks and seat post between the wheels, without requiring external supports, stands, or additional stabilization mechanisms. The design is self-stabilizing in the folded position.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the bicycle is designed for easy folding without tools, then ease of operation improves, but the folding mechanism may become too simple to maintain stability

Engineering Contradiction:
Improvetool-free foldingVSAvoidfolded position reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The bicycle transitions dynamically between unfolded and folded states through simple frame section movements. The folded position is maintained through the natural interlocking of components (cranks and seat post between wheels) rather than complex static locking mechanisms, achieving both ease of operation and reliability.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3873797B1Folding vehicle
Publication Date: 2025.04.23 NEWCYCLE INC
  • EP3873797B1 patent drawingFigure 1A
  • EP3873797B1 patent drawingFigure 1B
  • EP3873797B1 patent drawingFigure 1C

AI summary

A folding vehicle is adjustable between an unfolded position and a folded position. In the unfolded position, the wheels of the vehicle are in a leading and trailing relationship. In the folded position, the components of the folding vehicle have a minimal footprint allowing for compact storage. In the folded position, the wheels maybe in a side-by-side relationship with the majority of the vehicle components positioned between the wheels.