Prosthetic Liner Sealing Ring Vacuum Retention

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional prosthetic limb liners for below the knee amputations cause discomfort due to increased friction and pressure, leading to skin breakdown and reduced mobility, as they rely heavily on friction for attachment and are prone to air seal breakdown from sweat and muscle movement.

Innovation Solution

A flexible liner with an upwardly extending sealing ring that creates a vacuum seal when turned inside out and rolled onto the residual limb, reducing reliance on friction and allowing for anatomical cutouts to prevent interference with joint deflection, thereby enhancing comfort and motion while maintaining retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the liner is made long to encase the knee and extend into the thigh for below the knee amputations, then the retention and attachment security is improved, but the discomfort and skin breakdown risk increases due to friction and pressure

Engineering Contradiction:

ImproveretentionVSAvoiddiscomfort and skin breakdown

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The liner is segmented into functional zones: a shortened main body that does not encase the knee, and a separate sealing ring that provides attachment security. This segmentation allows the liner to be shortened for comfort while maintaining retention through the sealing ring mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sealing ring acts as an intermediary element between the liner and the residual limb. It provides the necessary retention and seal without requiring the entire liner to be in contact with the skin, thereby reducing friction and pressure on the knee and thigh areas.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the liner is cut short to eliminate knee encasement and reduce friction, then comfort and mobility are improved, but the retention and vacuum seal reliability deteriorates

Engineering Contradiction:

Improvecomfort and mobilityVSAvoidretention

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The sealing ring incorporates a localized high-friction or adhesive surface quality that provides enhanced retention at the seal location. This allows the rest of the liner to be short and comfortable while the sealing ring provides the necessary grip for retention.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The sealing ring extends upwardly from the liner in a vertical dimension, creating a seal that reaches higher on the residual limb. This vertical extension provides a reliable seal and retention point without requiring the liner itself to be long, thus maintaining comfort while improving retention.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the liner relies on friction for attachment, then the simplicity and ease of manufacture is maintained, but the air seal reliability breaks down from sweat and muscle movement

Engineering Contradiction:

ImprovesimplicityVSAvoidair seal

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The sealing ring replaces the reliance on friction-based mechanical attachment with a vacuum seal mechanism. The upwardly extending seal creates a vacuum barrier that is not dependent on friction, thereby preventing air leakage from sweat and muscle movement while maintaining manufacturing simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If the liner material is made flexible to allow turning inside out for seal positioning, then the ease of operation is improved, but the structural integrity and sealing capability may be compromised

Engineering Contradiction:

Improveease of donning and seal positioningVSAvoidsealing capability

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The liner material parameters are optimized to provide both flexibility for turning inside out and sufficient strength for sealing. The material is selected or engineered to have appropriate elastic properties that allow reversible deformation during donning while maintaining structural integrity for creating and holding the vacuum seal.

Inventive Principle:

Principle #35Parameter changes

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 comfortable and secure attachment of the prosthetic limb, allowing increased motion without sacrificing retention, by creating a vacuum seal that is not dependent on frictional contact, thus reducing discomfort and skin breakdown risks.

Implementation Method 1

creates a vacuum seal when turned inside out and rolled onto the residual limb

Methodology Applied

Scientific EffectVacuum seal: Vacuum

Data Source

PatentUS10004613B1Limb socket liner sealing system

Publication Date: 2018.06.26 KONIUK WAYNE A

AI summary

A prosthetic limb attachment system, for attaching a residual limb segment having a distal end to a prosthetic limb having a socket having an open proximal end and a closed distal end, using a liner. The liner is made of a flexible material and has an open proximal end, a closed distal end, and liner walls extending therebetween. The liner has a sealing ring extending laterally inwardly from the walls that has a central opening. The liner is turned inside out and the liner walls are rolled up onto the residual limb segment so that the sealing ring may be positioned against the residual limb segment, oriented upwardly thereupon, to create a vacuum seal such that downward forces on the liner will only increase the vacuum seal with the residual limb segment.