Prosthetic Socket Interface With Stepped Indentations
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Solution Overview
Problem
Current human limb prosthetic interfaces face challenges in providing consistent retention and comfort, often leading to skin irritation and pain due to irregular surfaces and inconsistent donning processes, especially when vacuum features are used.
Innovation Solution
The interface features strategically placed and shaped indentations, such as stepped structures or octagonal perforations, on its inner surface, which increase the holding force while minimizing skin irritation by distributing pressure more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If small spikes or protrusions are introduced on the inner surface to enhance retention, then retention capability is improved, but skin irritation and pain increase
Solution Approach 1:
The patent applies local quality by creating specific localized regions (indentations) on the inner surface with different geometric properties from the surrounding areas. These indentations are strategically positioned to provide enhanced retention through vacuum sealing while maintaining a smooth overall surface that prevents skin irritation. The local modification of surface geometry at specific locations resolves the contradiction between needing retention enhancement and avoiding harmful skin effects.
Solution Approach 2:
The patent utilizes a porous or cavitated surface structure through the indentations that can trap vacuum pressure. These indentation cavities act similarly to porous structures by providing volume for vacuum sealing while maintaining external smoothness. The indentations create localized void spaces that enhance vacuum retention without requiring protruding elements that would contact and irritate the skin.
2Reliability
If irregular surface structures are used to enhance connection, then retention is improved, but donning process consistency deteriorates
Solution Approach 1:
The patent segments the inner surface into distinct regions: smooth areas for comfortable skin contact and localized indentations for vacuum retention. This segmentation allows the different functional requirements (smooth donning vs. strong retention) to be satisfied in different zones, resolving the contradiction between connection strength and donning consistency.
Solution Approach 2:
Instead of using protrusions extending inward to create retention (the conventional approach), the patent inverts the approach by using indentations or cavities that extend outward or inward in a controlled manner. This inversion allows the retention mechanism to work through vacuum pressure in the cavities rather than through mechanical interlocking with protrusions, thereby improving both retention and donning consistency.
3Object-affected harmful factors
If smooth inner surface is used, then skin comfort is improved, but retention capability deteriorates
Solution Approach 1:
The patent maintains a smooth inner surface for skin comfort while introducing localized indentations with specific geometric properties to enhance retention. The smooth quality is preserved in the regions contacting the skin, while local variations in the form of indentations provide the necessary vacuum sealing capability. This local differentiation resolves the contradiction between comfort and retention.
Solution Approach 2:
The patent addresses the retention problem by moving from a two-dimensional smooth surface to a three-dimensional structure with indentations that create volume and cavity spaces. This dimensional change allows vacuum pressure to be effectively trapped and utilized for retention while the outer surface remains smooth for comfort. The third dimension (depth of indentations) provides the retention mechanism without compromising the two-dimensional smooth surface quality.
Data Source
AI summary
An interface for use in conjunction with a prosthetic device is formed of a pliable material which is configured to support the necessary connection to a residual limb when used. The interface further has an internal surface structure that includes several stepped indentations which provide a more efficient and effective product. The stepped indentations have a dimension which decreases as the distance from the interior surface increases. In some embodiments, the indentations are shaped as an octagon, with each step also being octagonal. Other shapes are also contemplated. Also, the steps of the indentations could be uniform or irregular.