Adjustable Seal System for Prosthetic Limbs
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Solution Overview
Problem
Existing suspension liners for prosthetic sockets often fail to adequately accommodate volume fluctuations and anatomical variations of residual limbs, leading to discomfort and pressure marks, particularly for trans-tibial amputees with bony protuberances and irregular shapes.
Innovation Solution
An adjustable seal system with seal bands and a textile sleeve that can be placed along the height of the liner to avoid pressure points, accommodate shape changes, and provide a secure, anatomically conforming fit, using polymeric materials and textile covers to interlock and provide a flexible, airtight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed seal structure is used in the liner, then manufacturing is simpler, but it cannot accommodate volume fluctuations and anatomical variations of residual limbs
Solution Approach 1:
The seal component is designed with a flexible membrane that can dynamically adjust its position and shape along the liner height. The membrane includes radial seals that can move radially and axial seals that can move axially, allowing the seal to adapt to volume fluctuations and anatomical variations of the residual limb while maintaining a relatively simple overall structure.
2Shape
If the seal component is made rigid to provide structural support, then it provides better rotational control, but it cannot conform to irregular shapes of residual limbs
Solution Approach 1:
The seal component utilizes a flexible membrane constructed from elastomeric material that can conform to irregular shapes of the residual limb. The membrane includes radial seals and axial seals that flex to match anatomical contours while maintaining sufficient structural integrity to provide rotational control within the socket.
3Reliability
If the seal extends far radially outward to ensure sealing, then sealing effectiveness is improved, but it creates pressure marks and discomfort on the residual limb
Solution Approach 1:
The seal component applies sealing force locally at specific locations (radial seals and axial seals) rather than distributing force across the entire seal circumference. This localized sealing approach maintains effective sealing at critical interfaces while reducing overall pressure on the residual limb, preventing pressure marks and discomfort.
4Adaptability or versatility
If the liner material is made highly elastic to accommodate shape changes, then comfort is improved, but rotational control within the socket deteriorates
Solution Approach 1:
The seal component is segmented into distinct functional elements (radial seals, axial seals, and membrane sections) that can independently deform to accommodate shape changes. This segmentation allows the liner material to remain highly elastic for comfort while the segmented seal structure maintains rotational control through its distributed sealing points.
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 adjustable seal system enhances comfort and skin protection by accommodating volume changes and anatomical irregularities, reducing the need for fine hand movements during donning, and providing improved rotational control and durability.
Implementation Method 1
The internal surface is arranged to frictionally engage at least one of the plurality of seal bands and secure on the outer surface of the liner body
Data Source
AI summary
An adjustable seal system, seal component for use in the system, and method are provided for forming a sealing interface between a residual limb and a prosthetic socket. The seal component is selectively placed over the outer surface of a suspension liner including a plurality of seal bands, which the seal component may removably and securely engage.