Variable Stiffness Hinge for Prostheses Using Contact Lever

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing prostheses and orthoses face challenges in replicating natural joint motion, particularly in transitioning through cyclic sequences of limb movements, due to complex mechanical features that increase production costs and complicate adaptability to individual users.

Innovation Solution

A prosthesis or orthosis with a hinge joint system that includes a first and second member, a linkage element or actuator, a flexible member, and at least one contact stiffening element. The contact stiffening element provides a lever action along the flexible member, allowing for adjustable hinge stiffness between the first and second members, enabling variations in mechanical responses during different phases of limb movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex mechanical features are used in hinge joint systems to reproduce natural joint motion, then the ability to transition through cyclic sequences of limb movements is improved, but the production cost increases noticeably and adaptability to individual users becomes more complicated

Engineering Contradiction:

Improveability to transition through cyclic sequencesVSAvoidcomplex mechanical features

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the parameter of hinge stiffness dynamically during the gait cycle. A contact stiffening element is introduced that engages with the flexible member at specific moments to increase stiffness during weight-bearing phases, while allowing flexibility during swing phases. This parameter change enables natural motion reproduction without complex mechanical features.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The hinge joint system transitions from a static stiffness configuration to a dynamic one. The contact stiffening element is designed to engage and disengage based on the gait cycle phase, making the stiffness characteristic time-dependent. This dynamic adjustment allows the system to adapt to different phases of limb movement without requiring complex mechanical structures.

Inventive Principle:

Principle #15Dynamics

2Reliability

If complex mechanical features are used in hinge joint systems to reproduce natural joint motion, then the ability to transition through cyclic sequences is improved, but adaptability to individual users is complicated

Engineering Contradiction:

Improveability to transition through cyclic sequencesVSAvoidadaptability to individual users

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the hinge joint system into distinct functional components: a flexible member that provides baseline flexibility, and a separate contact stiffening element that can be independently adjusted. This segmentation allows users to be fitted with different configurations of the stiffening element based on their specific gait characteristics, maintaining adaptability while simplifying the overall mechanism.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If a contact stiffening element is introduced to vary hinge stiffness, then user customizability is simplified, but the mechanical structure becomes more complex

Engineering Contradiction:

Improveuser customizabilityVSAvoidmechanical structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The contact stiffening element acts as an intermediary component between the flexible member and the external environment. It mediates the interaction by providing a simple engagement mechanism that can be adjusted for different users without requiring complex control systems or multiple degrees of freedom. The element transfers and modifies forces in a straightforward manner, maintaining structural simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 allows for simple user customizability, providing a reliable mechanical structure that adapts to individual users' needs by varying hinge stiffness, thereby enhancing the comfort and natural motion of the prosthesis or orthosis.

Implementation Method 1

at least one contact stiffening element configured for being or entering in contact with the flexible member and for providing a lever action along a length of the flexible member

Methodology Applied

Scientific EffectLever action: Lever

Implementation Method 2

a flexible member connected at a first end portion to the second member and at a second end portion to the linkage element or the actuator

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20250195252A1Prosthesis or orthosis with variable hinge stiffness

Publication Date: 2025.06.19 AXILES BIONICS BV

AI summary

A prosthesis or orthosis comprising a hinge joint system for functionally assisting, enhancing, and/or replacing a hinge joint system of a human or animal subject, said hinge joint system comprising: a first member (10); a second member (20) being pivotally attached to the first member; a linkage element or an actuator (30) connected to the first member; a flexible member (40) connecting the second member and the linkage element or the actuator; at least one contact stiffening element (50) configured for being or entering in contact with the flexible member and for providing a lever action along a length of the flexible member.