Variable Tension Prosthetic Liner with Zoned Elasticity

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Solution Overview

Problem

Conventional prosthetic suspension liners and sleeves often fail to conform comfortably to users with less conventional limb shapes, leading to material bunching and discomfort during knee movement due to inadequate elastic stiffness distribution, which is labor-intensive and costly to address with multiple fabric sections and seams.

Innovation Solution

A continuously elasticized fabric layer with regions of different elasticity, formed through varying knitting structures, eliminates the need for multiple sections and seams, providing a flexible and thinner fabric that accommodates a range of anatomies and motions without additional layers or stitching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple fabric sections with different elastic stiffness are stitched together, then the prosthetic device can accommodate different anatomies and movements, but the fabrication process becomes labor-intensive and expensive

Engineering Contradiction:

Improveaccommodation of different anatomies and movementsVSAvoidfabrication process complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The fabric is segmented into different zones with varying knitting structures within a single continuous layer, allowing different elastic stiffness regions without physical stitching of separate sections

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple fabric sections with different elastic properties are merged into a single continuously knit fabric layer, eliminating the need for stitching while maintaining variable elasticity across different anatomical regions

Inventive Principle:

Principle #5Merging (Combining)

2Strength

If multiple fabric sections are stitched together to provide different elastic stiffness, then the desired elasticity distribution is achieved, but seams are created that complicate fabrication and reduce flexibility

Engineering Contradiction:

Improveelastic stiffness distributionVSAvoidseams and stitching

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

Multiple fabric sections are merged into a single continuously knit fabric layer, eliminating seams while maintaining variable elasticity through different knitting structures in different zones

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Different zones of the fabric have different knitting structures tailored to specific anatomical regions, providing locally optimized elastic properties without requiring separate fabric sections or seams

Inventive Principle:

Principle #3Local quality

3Strength

If additional fabric layers are added to provide different elasticity, then the elastic stiffness distribution is improved, but the overall thickness increases adding weight and reducing flexibility

Engineering Contradiction:

Improveelastic stiffness distributionVSAvoidoverall weight of prosthetic device

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

Instead of adding more layers in the vertical dimension, the patent varies the knitting structure within the single fabric layer, achieving different elastic properties through structural variation rather than layer multiplication

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Different zones within the single fabric layer have different knitting densities and structures, providing locally optimized elastic properties without increasing overall fabric thickness or weight

Inventive Principle:

Principle #3Local quality

4Strength

If additional fabric layers are added to provide different elasticity, then the elastic stiffness distribution is improved, but the fabrication process becomes more complex and costly

Engineering Contradiction:

Improveelastic stiffness distributionVSAvoidfabrication process

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Multiple fabric layers are merged into a single continuously knit fabric, simplifying fabrication by eliminating the need to handle, align, and stitch multiple separate layers

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single fabric layer is segmented into different knitting zones during the knitting process itself, allowing variable elasticity to be built-in during manufacturing rather than requiring post-fabrication assembly of multiple layers

Inventive Principle:

Principle #1Segmentation

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 comfortable and cost-effective fabrication of prosthetic devices that adapt to various anatomies and movements, reducing discomfort and weight while maintaining flexibility and airtight seals, by distributing elastic stiffness uniformly across the fabric layer.

Implementation Method 1

a continuously elasticized fabric layer having regions of different elasticity

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP3035896B1Variable tensioned prosthetic device including continuously elasticized fabric

Publication Date: 2020.05.06 OSSUR ICELAND EHF

Figure 1~2
Figure 3~4
Figure 5

AI summary

A prosthetic device includes first and second regions (12, 14) divided by a longitudinal line (19) extending between the first and second ends (34, 36) of the device (10). The device (10) has a continuously knit elasticized fabric layer (32) including a first set of yarns (28) located about a circumference of the device (10) through the first and second regions (12, 14). The fabric layer (32) has different knit structures in the first and second regions (12, 14) to obtain different elasticity while sharing the first set of yarns (28) so that the first region (12) has a first elasticity, and the second region (14) has a second elasticity greater than the elasticity of the first region (12). An elastomeric layer (30) secures an interior surface of the fabric layer (32).