Variable Section Bicycle Frame Diagonal Tube
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Solution Overview
Problem
Bicycle frames face a trade-off between achieving maximum rigidity for control and stability while minimizing weight, with conventional designs often compromising on rigidity to reduce weight, leading to energy loss and inadequate protection from environmental particles.
Innovation Solution
A double-acting diagonal tube with a variable, polygonal section that maximizes moment of inertia in the critical middle-upper zone for enhanced stiffness and protection, incorporating a curved-concave design to act as a mudguard, integrating protective functions without significant weight or assembly complications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the diagonal tube section is increased to maximize rigidity in the critical middle-upper zone, then the moment of inertia and structural stiffness are improved, but the weight of the frame increases
Solution Approach 1:
The patent applies local quality by varying the diagonal tube section dimensions along its length, specifically increasing the section in the critical middle-upper zone while maintaining smaller sections in less critical areas. This allows maximum moment of inertia where needed for rigidity while minimizing weight in non-critical zones, resolving the contradiction between strength and weight through spatially differentiated structural properties.
Solution Approach 2:
The patent implements dynamics by transitioning from a constant section diagonal tube to a variable section design where the tube dimensions change along its length. This dynamic adaptation of structural properties allows the frame to optimize rigidity exactly where required (middle-upper zone) rather than uniformly throughout, reducing overall weight while maintaining necessary strength characteristics.
2Stability of the object's composition
If the diagonal tube is designed with maximum rigidity, then control and stability are improved, but energy loss increases due to frame deformations under pedaling forces
Solution Approach 1:
By concentrating the increased section dimensions in the critical middle-upper zone where rigidity is most needed, the patent minimizes frame deformations under pedaling forces in the areas that contribute most to energy loss. The variable section design ensures maximum stiffness where pedaling forces are applied while avoiding unnecessary weight and potential deformation in less critical zones, thereby reducing overall energy loss.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the diagonal tube with enhanced section dimensions in the critical zone before the bicycle is subjected to pedaling forces. This anticipatory design ensures that the frame structure is already optimized to resist deformations and minimize energy loss under the expected loading conditions, rather than reacting to deformations after they occur.
3Object-affected harmful factors
If conventional mudguards and protective plates are added to protect against particles, then protection is improved, but device complexity and assembly complications increase
Solution Approach 1:
The patent merges the protective function previously performed by separate mudguards and protective plates directly into the diagonal tube structure itself. By integrating the protection function into the frame's diagonal tube through strategic section enlargement in the middle-upper zone, the design eliminates the need for additional detachable components, thereby reducing device complexity and assembly requirements while maintaining effective protection against particle impacts.
Solution Approach 2:
The diagonal tube is designed to perform multiple functions simultaneously: it provides structural support, achieves rigidity, and offers protection against particle impacts. By making the diagonal tube multi-functional, the patent eliminates the need for separate dedicated protective components, reducing overall device complexity while maintaining comprehensive protection capabilities against mud and loose terrain conditions.
Data Source
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AI summary
Bicycle frame, of the type which consist of a diagonal tube (1) of quadrangular section, in which at least in the mid-upper zone (11) of the diagonal tube (1) which faces the bicycle wheel, the outer side (10) of said quadrangular section is concave, and the size (a) of said outer side (10) increases approximately from the upper section (A:A) to the central section (C:C) of the diagonal tube (1).