Composite Flexible Torsion Shaft for Symmetrical Torque Transmission

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Solution Overview

Problem

Existing air-conditioning duct cleaning devices using steel cables suffer from asymmetrical torque transmission and excessive weight, making them cumbersome and inefficient.

Innovation Solution

A flexible torsion shaft with a cross-braided composite cable, comprising epoxy and glass fibre reinforcement, is developed, featuring symmetrical torque properties and reduced weight, manufactured through pultrusion with specific winding angles and materials to enhance strength and stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a steel cable is used for the flexible shaft, then torque can be transmitted, but the torque transmission is asymmetrical and the weight is excessive

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidweight of flexible shaft
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by replacing the traditional steel cable with a flexible shaft made of fiber-reinforced plastic composite. The shaft consists of a plastic matrix material reinforced with fibers (such as glass, carbon, or aramid fibers) arranged in specific patterns. This composite structure provides both the necessary mechanical strength for torque transmission and significant weight reduction compared to solid steel cables, directly resolving the contradiction between reliability and weight.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a steel cable is wound to transmit torque, then torque can be transmitted, but the torque properties become asymmetrical

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidsymmetrical torque properties
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies asymmetry principle in reverse by deliberately designing a symmetrical structure to eliminate asymmetrical torque properties. The flexible shaft uses fibers wound at specific angles (typically ±45 degrees relative to the longitudinal axis) in a balanced configuration. This symmetrical fiber arrangement ensures that the shaft exhibits identical torque transmission characteristics in both clockwise and counter-clockwise directions, resolving the asymmetry problem while maintaining torque transmission capability.

Inventive Principle:
Principle #4Asymmetry

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 solution provides a more user-friendly and efficient cleaning device with improved torque transmission and reduced weight, suitable for various applications including air-conditioning duct cleaning.

Implementation Method 1

The flexible shaft is suitable for transmitting a torsion force in many applications

Methodology Applied
Scientific EffectTorsion: Torque

Implementation Method 2

the material hardness and other properties will minimize friction

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The body of the torsion shaft is preferably epoxy and the reinforcing fibres are mainly glass fibre

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 4

several layers are wound around a core wire, at different winding angles, in order to achieve the desired strength and stiffness properties

Methodology Applied
Scientific EffectStrength:

Data Source

PatentEP3268139B1Flexible torsion shaft, arrangement and device for cleaning air-conditioning ducts
Publication Date: 2024.12.18 BIERKUHL OY
  • EP3268139B1 patent drawingFigure 1~3
  • EP3268139B1 patent drawingFigure 4
  • EP3268139B1 patent drawingFigure 5~6

AI summary

The invention relates to a flexible torsion shaft (12), which is intended to be attached to a drive shaft, characterized in that the flexible torsion shaft (12) is composite comprising a polymeric base substance (17, 17') and a multi-layer (16, 16", 16"') reinforcing-fibre reinforcement wound at an angle of 45° - 85°, preferably an angle of 60° - 80°.