Prosthetic Liner Seal with Radial Element
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Solution Overview
Problem
Existing suspension liner sleeves for prosthetic sockets face challenges in providing a reliable seal, especially for trans-tibial amputees due to bony protuberances and irregular shapes, which complicates the sealing process and reduces the effectiveness of vacuum retention.
Innovation Solution
An elastomeric liner sleeve with a resilient seal element that extends radially around the peripheral portion, combined with reinforcement material for axial stiffness, enhances sealing by distributing tension and accommodating irregularities, creating a positive seal that maintains suction and resists withdrawal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple elastomeric liner sleeve is used without a seal element, then the device complexity is reduced, but the sealing reliability deteriorates due to bony protuberances and irregular shapes preventing effective sealing
Solution Approach 1:
A separate seal element is introduced as an intermediary component between the elastomeric liner sleeve and the socket. This seal element specifically addresses the sealing challenge by conforming to irregular socket surfaces and bony protuberances, while the liner sleeve itself remains relatively simple in structure.
Solution Approach 2:
The system combines different materials with complementary properties: the elastomeric liner sleeve provides comfort and basic conformity, while the seal element (made of silicone rubber or similar material) provides the sealing function. This composite approach allows each component to be optimized for its specific function.
2Ease of operation
If the liner sleeve is made thick to provide cushioning, then the comfort is improved, but the axial stiffness deteriorates causing excessive elongation under tension
Solution Approach 1:
The liner sleeve is designed with non-uniform thickness, being thicker at the distal end for cushioning and comfort, and thinner at the proximal end to reduce weight and improve donning. This local variation in thickness allows comfort optimization without excessive overall mass.
Solution Approach 2:
The liner sleeve combines elastomeric material for comfort with embedded reinforcement fibers (such as polyester or nylon) to provide axial stiffness. This composite structure allows the sleeve to be thick enough for cushioning while the reinforcement prevents excessive elongation under tension.
3Strength
If reinforcement material is added to provide axial stiffness, then the structural integrity is improved, but the radial flexibility deteriorates restricting natural distension
Solution Approach 1:
The reinforcement material is strategically placed within the liner sleeve structure, typically as embedded fibers or a reinforcement layer. This localized reinforcement provides axial stiffness where needed while allowing the outer elastomeric surface to maintain radial flexibility for natural distension and conformity to the residual limb.
Solution Approach 2:
The liner sleeve uses a composite construction with elastomeric base material providing radial flexibility and embedded reinforcement fibers (polyester, nylon, or similar) providing axial stiffness. The composite structure allows independent optimization of radial and axial mechanical properties.
4Reliability
If multiple seal elements are used to improve sealing, then the sealing reliability is improved, but the device complexity increases
Solution Approach 1:
The seal element is designed as a segmented or multi-lobe structure that can conform to irregular socket surfaces. The segmentation allows the seal to adapt to bony protuberances and irregular shapes while maintaining a single integrated component, avoiding the complexity of multiple separate seal elements.
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 convenient and improved sealing arrangement that effectively retains the liner sleeve within the socket, maintaining suction and allowing easy withdrawal by isolating the distal end from the atmosphere, enhancing comfort and security for trans-tibial amputees.
Implementation Method 1
a resilient seal element which is radially protruding from a liner sleeve body portion
Implementation Method 2
a suction is created in the distal end of the socket tending to retain the liner sleeve within the socket
Data Source
AI summary
A suspension liner sleeve providing an interface between a residual limb and a hard prosthetic socket includes a resilient seal element extending around its outer periphery to enhance a sealing effect between the sleeve and the interior of a prosthetic socket to isolate the distal end of the socket from atmosphere after the sleeve with a residual limb has been inserted within the socket and to thereby improve the retention of the liner sleeve and the residual limb in the prosthetic socket.