Foldable Bicycle Frame Longitudinal Folding Mechanism
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Solution Overview
Problem
Existing foldable bicycle frames often require additional tools or excessive force to ensure all elements are securely positioned during unfolding, and they can be dangerous if clamping mechanisms loosen during a ride, especially when folded along a longitudinal plane.
Innovation Solution
A foldable bicycle frame design featuring a dual-axis swivel mechanism that allows folding along the longitudinal plane without removing the rear wheel, with a secure connection between the seat tube and rear section using clamps, and optional integration of a shock-absorber for vibration absorption, enabling easy and secure unfolding without additional tools or force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a foldable bicycle frame is designed to fold along the longitudinal plane, then the folded width is reduced and compactness is improved, but the security of connection between frame elements deteriorates and may loosen during riding
Solution Approach 1:
The intermediate seat tube is inserted inside the seat tube, creating a nested structure that provides multiple connection points and layers of security. This nested arrangement allows the frame elements to be securely connected while maintaining the ability to fold along the longitudinal plane, thus reducing folded width without compromising connection security.
Solution Approach 2:
The frame elements are pre-configured with connection mechanisms (such as clamps and locking features) that automatically engage and secure the connection before riding begins. This preliminary preparation ensures that the connection security is established in advance, preventing loosening during riding while allowing compact folding when not in use.
2Strength
If traditional clamping mechanisms are used to secure foldable elements, then connection strength is improved, but the ease of operation deteriorates due to requiring additional tools or excessive force
Solution Approach 1:
The connection mechanisms are designed to be self-securing, automatically engaging and locking frame elements together without requiring external tools or excessive force. The self-service nature of these mechanisms maintains strong clamping strength while significantly improving ease of operation, allowing users to quickly assemble and secure the frame.
Solution Approach 2:
Intermediary components such as spring-loaded clamps or cam-lever mechanisms are introduced to mediate between the user's simple action and the required strong clamping force. These intermediary elements amplify the user's input force or provide automatic locking, achieving both strong connections and easy operation without requiring tools or excessive manual force.
3Adaptability or versatility
If detachable connection mechanisms are used to enable folding, then the adaptability for storage and transport is improved, but the reliability of connection during riding deteriorates
Solution Approach 1:
The nested arrangement of the intermediate seat tube within the seat tube creates multiple interlocking connection points that maintain reliability during riding. The detachable nature is preserved at the overall frame level for storage adaptability, while the nested nested elements provide secure, tool-free connections that prevent loosening during use.
Solution Approach 2:
The connection mechanisms are designed with preliminary locking features that automatically engage and secure frame elements before riding begins. This preliminary action ensures that the detachable connections are transformed into reliable, fixed connections during riding, maintaining both storage adaptability and riding reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design provides a lightweight, compact, and secure foldable bicycle frame that can be easily unfolded for riding, ensuring all elements are securely locked in place without the need for additional tools or excessive force, and absorbs vibrations for a smoother ride.
Implementation Method 1
optional integration of a shock-absorber for vibration absorption, enabling easy and secure unfolding without additional tools or force
Data Source
AI summary
A foldable bicycle frame includes a rigid element connecting a head with a seat tube, a rear section of the frame, a coupler, and an intermediate seat tube. The front upper part of the rear section of the frame is pivotally connected to the intermediate seat tube. The front bottom part of the rear section of the frame is pivotally connected to the coupler. The other end of the coupler is pivotally connected to the rigid element. The intermediate seat tube is operable to be inserted into the seat tube while unfolding the frame.