Bicycle Frame with Arcuate Down Tube and Flexing Top Tube

Solution Overview

Problem

Conventional bicycle frames are either too rigid, leading to an uncomfortable ride over rough terrain, or overly flexible, resulting in energy loss and decreased pedaling efficiency, with no adjustable options for different riders or conditions.

Innovation Solution

A bicycle frame design featuring a top tube that vertically flexes and a down tube with arcuate shape, made from materials like carbon fiber and titanium, allowing for adjustable flexibility and stiffness to enhance energy efficiency and ride smoothness, while resisting torsional flex.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional rigid frame structure is used, then lateral stiffness is maintained, but vertical flexibility is insufficient causing harsh ride

Engineering Contradiction:

Improvelateral stiffnessVSAvoidvertical flexibility

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The frame incorporates selective flexibility in specific tubes (top tube with ovalized section, down tube with arcuate shape) while maintaining rigidity in other areas. This local differentiation allows vertical flex where needed for comfort while preserving lateral stiffness for stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The down tube features an arcuate shape with at least one arc, and the top tube includes an ovalized section. These curved geometries provide inherent flexibility in the vertical direction while maintaining structural integrity and lateral stiffness through the curved form.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of operation

If springs and shock absorbers are added to increase vertical cushioning, then ride comfort is improved, but device complexity and weight increase

Engineering Contradiction:

Improvevertical cushioningVSAvoidframe structure complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the need for separate spring and shock absorber components by integrating flexibility directly into the frame tubes themselves. The arcuate down tube and ovalized top tube sections provide cushioning through their geometric properties alone, eliminating extra components.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The frame structure merges the functions of structural support and shock absorption into a single integrated system. The flexible tube sections simultaneously provide structural integrity and vertical cushioning, combining what were previously separate functions.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If frame flexibility is increased to absorb shocks, then vertical cushioning is improved, but lateral or torsional rigidity decreases

Engineering Contradiction:

Improvevertical cushioningVSAvoidlateral or torsional rigidity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The frame incorporates selective flexibility in specific tubes (top tube with ovalized section, down tube with arcuate shape) while maintaining rigidity in other areas. This local differentiation allows vertical flex where needed for comfort while preserving lateral stiffness for stability.

Inventive Principle:

Principle #3Local quality

4Use of energy by moving object

If frame stiffness is maximized to improve energy efficiency, then pedaling power delivery is enhanced, but ride harshness increases

Engineering Contradiction:

Improveenergy efficiencyVSAvoidride smoothness

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The down tube features an arcuate shape with at least one arc, and the top tube includes an ovalized section. These curved geometries provide inherent flexibility in the vertical direction while maintaining structural integrity and lateral stiffness for energy efficiency.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 frame provides a smoother ride, increased energy efficiency, and adjustable characteristics for various riders and conditions by combining vertical flexibility with lateral stiffness, enhancing pedaling power delivery and accommodating different riding styles.

Implementation Method 1

The down tube has at least one arc and springs back to its original position from forces of tension as well as compression

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8991848B2Bicycle frame

Publication Date: 2015.03.31 ALTER CYCLES

AI summary

In accordance with the present invention, an improved bicycle frame according to one embodiment of this invention has a top tube that allows the wheel base to lengthen by resiliently flexing or pivotally deflecting vertically while resisting torsional flex This feature is combined with a resilient, flexible, arcuate down tube extending between the bottom bracket of the bicycle and the bicycle head tube or the intermediate connection points The down tube has at least one arc and springs back to its original position from forces of tension as well as compression The combination of the two flexing members gives the bicycle a smoother ride and may also enhance the delivery of pedal” power to the rear wheel The down tube is replaceable in order to modify the flex characteristics of the frame and physical characteristics, such as head tube and seat tube angle, wheel base, and bottom bracket height.