Composite Bicycle Fork Structure With Replaceable Vibration Damper

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Solution Overview

Problem

Existing bicycle structural elements, such as forks, face challenges in integrating a vibration damping system without compromising mechanical strength and in allowing for easy replacement of the damping device when it becomes worn or defective, while also maintaining optimal vibration absorption and filtration efficiency.

Innovation Solution

A bicycle structural element with an internal partition that forms cavities for housing a removable and interchangeable dynamic beater, where the beater is fixed within the tubular sheath using screws and an elastomeric lining, allowing for adjustable stiffness and mass to optimize vibration damping, and the structural element is made of composite materials like carbon fibers embedded in resin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a vibration damping system is integrated into the fork structure, then vibration filtration efficiency is improved, but the complexity of the device increases

Engineering Contradiction:
Improvevibration filtration efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The damping system is nested within the hollow interior of the fork sheath, with the blade housed inside the tubular structure. This nesting approach integrates the damping function into the existing fork geometry without requiring external attachments or separate mounting structures, thereby improving vibration filtration while minimizing additional complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The fork is segmented into functional zones: the outer sheath structure and the internal damping system. The sheath is divided into a first portion (outer wall) and a second portion (inner partition), creating distinct cavities that accommodate the damping blade while maintaining structural integrity. This segmentation allows independent optimization of both structural strength and damping performance.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If the damping system is made permanent in the fork structure, then vibration absorption is improved, but the ease of repair deteriorates

Engineering Contradiction:
Improvevibration absorptionVSAvoidease of repair
Core Design Contradiction:
Object-affected harmful factorsVSEase of repair

Solution Approach 1:

The damping blade is designed with dynamic characteristics - it is flexible rather than rigid, allowing it to adapt its stiffness and damping properties based on vibration conditions. The blade can flex within the cavity and is not permanently fixed to the sheath walls, enabling easy removal and replacement while maintaining effective vibration absorption during operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The damping blade is extracted as a separate, removable component from the fork structure. It is not permanently bonded or integrated into the sheath, but rather positioned within the internal cavity where it can be easily accessed, removed, and replaced. This extraction approach maintains vibration absorption performance while dramatically improving ease of repair and maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of repair

If the damping system is made removable and interchangeable, then the ease of repair is improved, but the reliability deteriorates

Engineering Contradiction:
Improveease of repairVSAvoidreliability
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The fork sheath is pre-configured with an internal cavity and structural features that accommodate the damping blade before the blade is installed. The sheath includes a defined housing space with appropriate geometry and attachment points, ensuring that when the blade is installed, it is properly positioned and secured. This preliminary preparation ensures reliable operation while maintaining ease of replacement.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The damping blade design allows it to self-secure within the fork sheath through its own geometric features and elastic properties. The blade's flexibility and the cavity's configuration enable the blade to maintain its position and functional integrity without complex external fastening mechanisms, ensuring reliable vibration damping while allowing easy user replacement.

Inventive Principle:
Principle #25Self-service

4Weight of moving object

If composite materials are used to reduce fork weight, then the weight of the object is improved, but the strength of the object deteriorates

Engineering Contradiction:
Improvefork weightVSAvoidfork strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The fork sheath is constructed from composite materials that combine lightweight properties with high strength characteristics. The composite structure allows the sheath to maintain sufficient mechanical strength to support the damping system and withstand riding loads while significantly reducing the overall weight compared to traditional metal forks.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The sheath structure exhibits local quality variations - different portions of the sheath have different thicknesses, material densities, or fiber orientations optimized for their specific functional requirements. The outer wall and inner partition are designed with locally adapted properties to provide strength where needed while minimizing weight in non-critical areas, and to create appropriate cavities for the damping blade.

Inventive Principle:
Principle #3Local quality

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

Enables effective vibration filtration and absorption, allowing for easy replacement of the damping system to adapt to varying road conditions and cyclist needs, while maintaining mechanical strength and reducing wear on bicycle components.

Implementation Method 1

a device for filtering and absorbing vibratory energy or beater, comprising at least one blade... The vibrations to which the wheel is subjected are transmitted to the blade, via the connection zone with the fork, in the form of oscillations. As a result, the strip in contact with the blade is subjected to tangential forces resulting from the oscillations of the blade which lead to a deformation by shearing and therefore a dissipation of the vibratory energy.

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

The blade is made of a first substantially rigid material and is attached to at least one strip made of a second substantially elastic material.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3501958B1Structural element of a cycle provided with a device for damping vibrations and method for manufacturing such an element
Publication Date: 2023.07.05 CARDINAL CYCLING GRP
  • EP3501958B1 patent drawingFigure 1~2
  • EP3501958B1 patent drawingFigure 3A~3B
  • EP3501958B1 patent drawingFigure 4A~4C

AI summary

The invention relates to a structural element of a cycle comprising at least one tubular sleeve (10) having an outer wall (101, 102) delimiting, with an inner partition (100), at least one cavity (11, 12) in which a vibration damping system (2) is housed, characterized in that said sleeve (10) comprises at least two internal cavities (11, 12) each delimited between said inner partition (100) and the outer wall (101, 102), one of said internal cavities (12) forming a housing in which said damping system (2) is housed and fixed.