Prosthetic Limb Seal with Removable Toric Ring Anchoring

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Solution Overview

Problem

Existing sealing devices in prosthetic limbs suffer from rapid deterioration and risk of tearing due to repeated insertion and withdrawal maneuvers, leading to insufficient durability and reliability, along with high maintenance and replacement costs.

Innovation Solution

A sealing device featuring a deformable annular diaphragm with a toroidal ring anchoring member that can be easily installed and removed, allowing the seal to be pinched between the ring and the reserve, enabling reliable connection while facilitating easy replacement and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing member is placed at the proximal end of the shell to ensure airtightness between the sleeve and the shell, then airtightness is improved, but the seal deteriorates rapidly and risks tearing due to repeated insertion and withdrawal maneuvers

Engineering Contradiction:
ImproveairtightnessVSAvoiddurability of seal
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The sealing system is segmented into three distinct components: the seal member (O-ring), the retainer ring, and the reserve. This segmentation allows the seal to be easily replaced without replacing the entire assembly, improving durability by enabling maintenance of the wear-prone seal while retaining the durable retainer and reserve structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retainer ring is designed with flexibility to dynamically adapt during insertion and withdrawal maneuvers. The retainer ring can deform elastically to accommodate the seal and then return to its original position, maintaining airtightness while withstanding repeated mechanical stress without deteriorating.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the edge of the seal is organized in a bead inside which the O-ring is embedded to prevent the edge from escaping, then the seal is retained, but it becomes difficult to position inside the reserve and increases replacement complexity

Engineering Contradiction:
Improveseal retentionVSAvoidease of installation and replacement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The retainer ring is extracted as a separate, removable component from the shell structure. This allows the retainer ring (with the seal already positioned on it) to be easily inserted into and removed from the reserve as a single assembly, greatly simplifying the replacement process while maintaining secure retention through the retainer ring's engagement with the reserve.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the seal is fixed to the inside of the shell or to the outside of the sleeve through bonding to ensure airtightness, then sealing is achieved, but the methods used for removing and installing the seal become complex and costly

Engineering Contradiction:
Improvesealing effectivenessVSAvoidease of seal replacement
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing system is divided into replaceable and permanent components. The seal member is designed as a separate, unbonded component that can be easily removed and replaced, while the retainer ring and shell/sleeve structures remain in place. This eliminates complex bonding operations and reduces replacement costs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retainer ring acts as an intermediary component that holds the seal member in place without requiring bonding to the shell or sleeve. The retainer ring's mechanical engagement with both the seal and the reserve provides secure retention while allowing easy removal and replacement of the seal assembly.

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 provides a durable and reliable sealing mechanism with reduced maintenance costs, allowing quick and easy installation and removal of the seal, while maintaining the integrity of the shell and sleeve, and enabling cost-effective replacement of the diaphragm without altering the existing components.

Implementation Method 1

A deformable seal is interposed between the shell and the sleeve to prevent air passage between them

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the seal is immobilized by pinching its corresponding edge between the rod and the bottom of the reserve

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Fastener

Data Source

PatentEP1875882B1Watertight device between a sleeve installed on the stump of an amputated member and a prosthesis shell
Publication Date: 2015.01.07 CHABLOZ COMPOSANTS
  • EP1875882B1 patent drawingFigure 1~3

AI summary

The device has a deformable joint (4) interposed between a shell (1) of prosthesis and a sleeve (2) to prevent a passage of air between the shell and the sleeve. The joint has an annular diaphragm whose edge has an anchoring unit with a toric ring (7) that is housed in a reserve (9) arranged in the sleeve and the shell. The edge has a return that delimits a ring receiving opening capacity such that the ring is removable to permit its easy installation and withdrawal from outside of a cavity (3) and that the joint is immobilized by pinching of the edge between the ring and the reserve bottom.