Exoskeleton Elastic Joint With Adjustable Restoring Torque

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Solution Overview

Problem

Existing exoskeletons lack adjustable support and spring mechanisms that can accommodate torsion and lateral inclination of the user's upper body while providing support during forward bending, with adjustment methods being cumbersome or adding weight.

Innovation Solution

A joint for elastic connection between exoskeleton elements, featuring a pivot joint, deflection pulley, and elastic element, allowing adjustable restoring torque through adjustable pulley diameter, enabling flexible support adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If pneumatic spring system with adjustable air pressure is used, then support intensity can be adjusted, but system complexity and user operation difficulty increase

Engineering Contradiction:
Improvesupport intensity adjustmentVSAvoidpneumatic spring system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the complex pneumatic spring system with a purely mechanical solution - a spring mechanism with adjustable pre-tensioning. The support intensity is adjusted by mechanically changing the initial tension of the spring through a tensioning element, eliminating the need for compressors, pressure reservoirs, and complex pneumatic components while achieving the same adaptability in support intensity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The spring mechanism is designed to be self-adjusting through user body movement. As the user moves their body, the spring automatically tensions and adjusts to provide appropriate support without requiring external power sources or complex control systems. The system serves itself by utilizing the user's own movements to regulate the support intensity.

Inventive Principle:
Principle #25Self-service

2Device complexity

If fixed support curve is used, then structure is simple, but adaptability to different users and activities is limited

Engineering Contradiction:
Improvesupport mechanism structureVSAvoidadjustment to different users and activities
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adjustability to the support mechanism by allowing the spring pre-tension to be changed during use. The tensioning element can be adjusted to modify the initial tension of the spring, which dynamically changes the support characteristics. This enables the same simple mechanical structure to adapt to different users, body weights, and activity requirements without changing the fundamental design.

Inventive Principle:
Principle #15Dynamics

3Force

If spring mechanism is made rigid to provide support, then support function is effective, but freedom of movement for unsupported movements is restricted

Engineering Contradiction:
Improvesupport torqueVSAvoidfreedom of movement
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent applies support force locally and selectively through the spring mechanism that acts only in the forward bending direction. The spring provides support torque when the user bends forward but does not restrict movement in other directions such as lateral inclination or torsion. This localized application of force maintains freedom of movement for unsupported movements while providing effective support where needed.

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

Provides adjustable support intensity and freedom of movement, accommodating torsion and lateral inclination, enhancing user comfort and adaptability to individual needs.

Implementation Method 1

an elastic element (3), in particular an elastic cable, which has a restoring force between the elements (1, 2)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The deflection element (3) is designed in such a way that, in a loaded state, it has a different course than in an unloaded state

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP4380759B1Exoskeleton having an elastic joint, and joint for elastic connection
Publication Date: 2025.07.09 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP4380759B1 patent drawingFigure 1
  • EP4380759B1 patent drawingFigure 2
  • EP4380759B1 patent drawingFigure 3

AI summary

The invention relates to an exoskeleton, comprising an upper body element and a leg connection means, which are interconnected by means of a joint for elastically rotatable connection. The invention also relates to a joint for elastic connection of two elements. Exoskeletons are used to reduce the load on the human body or to augment human power with an additional power source. Exoskeletons can be used for medical, economic, military or other reasons.