Exoskeletal Prosthesis with Zoned Flexibility for Limb Hardness Replication

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Solution Overview

Problem

Existing prosthetic limbs do not adequately replicate the natural feel and functionality of a lost limb, leading to cumbersome handling and an imperfect aesthetic.

Innovation Solution

An exoskeletal prosthesis structure with zones of varying flexibility, designed to mimic the different hardnesses of a natural limb, providing a connection between a socket and a hand or foot prosthesis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a prosthesis uses a uniform rigid structure to ensure strength and stability, then structural integrity is improved, but the realism and comfort of the replaced limb deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidrealism and comfort
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The exoskeletal structure is divided into multiple zones with different flexibility characteristics. Some zones are designed to be more flexible to mimic soft tissue, while other zones maintain higher rigidity to provide structural support. This local differentiation allows the prosthesis to simultaneously achieve structural integrity and realistic tactile feedback, resolving the contradiction between strength and comfort.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If a prosthesis uses a single-material construction to simplify manufacturing, then manufacturing complexity is reduced, but the ability to replicate different limb tissues deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidtissue replication capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The exoskeletal structure employs composite materials with varying flexibility characteristics in different zones. This allows the prosthesis to replicate the diversity of natural limb tissues (bone, muscle, fat, skin) while maintaining a manageable manufacturing process. The composite construction enables each zone to be optimized for its specific function without requiring complete redesign of the entire structure.

Inventive Principle:
Principle #40Composite materials

3Reliability

If a prosthesis envelope is made thicker to improve durability and protection, then protective capability is improved, but the weight and bulk increase

Engineering Contradiction:
Improvedurability and protectionVSAvoidprosthesis weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

Rather than uniformly thickening the entire envelope, the invention applies thicker protective layers only in zones where structural support and protection are most critical. In zones where flexibility and weight reduction are priorities, the envelope is made thinner. This localized approach maintains durability where needed while minimizing overall weight gain.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4106681B1Limb prosthesis
Publication Date: 2025.05.28 CHABLOZ ORTHOPEDIE
  • EP4106681B1 patent drawingFigure 1~2
  • EP4106681B1 patent drawingFigure 3~4
  • EP4106681B1 patent drawingFigure 5

AI summary

The invention relates to an exoskeletal structure, preferably having a tubular shape (1), of a prosthesis (12) of a given limb (2), the exoskeletal structure being designed to provide a connection - between a socket (29) and a hand prosthesis (37) or - between a socket (29) and a foot prosthesis (25) in order to form the prosthesis of the limb, the exoskeletal structure comprising at least two zones (5.1, 5.2, 6.1, 6.2) of different flexibility (3.1, 3.2, 3.3, 9.1, 9.2), wherein the arrangement of said zones between them corresponds to the arrangement of the parts of the given limb having different hardnesses (7, 8).