Bonded Prosthetic Liner With Foam Support and Wicking Channels
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Solution Overview
Problem
Existing prosthetic liners lack the ability to incorporate padding, bladders, or other supporting materials due to the high pressure required in standard molding processes, which deforms these materials.
Innovation Solution
A prosthetic liner design featuring a textured mandrill surface modification on the internal thermoplastic elastomeric layer allows for the inclusion of foam pads, spacer fabric, air bladders, fluid bladders, and other support materials, along with internal channels for moisture drainage and the integration of electrical relays and sensors, using heat and chemical bonding methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard injection molding or compression molding processes are used to bond the thermoplastic elastomeric layer to the fabric layer, then strong bonding and structural integrity are achieved, but supporting materials such as padding, bladders, or foam deform due to excessive heat and pressure
Solution Approach 1:
The patent divides the liner into distinct functional layers: an inner thermoplastic elastomeric layer, an outer fabric layer, and separate supporting material layers (foam, bladders, padding). This segmentation allows each layer to be optimized independently - the supporting materials can be positioned and secured without being subjected to the full heat and pressure of the bonding process, thus preventing deformation while maintaining strong interlayer bonding.
Solution Approach 2:
The supporting materials are pre-positioned and secured to either the inner or outer layer before the final bonding process. This preliminary action ensures that sensitive supporting materials are protected from excessive heat and pressure during molding, while still allowing subsequent bonding of the thermoplastic elastomeric layer to the fabric layer to achieve strong structural integrity.
2Reliability
If high pressure is applied during molding to ensure proper bonding, then reliable attachment of layers is achieved, but supporting materials become improperly configured or deformed
Solution Approach 1:
The patent applies different pressure levels to different regions of the liner during molding. High pressure is applied locally at the bonding interfaces between the thermoplastic elastomeric layer and fabric layer to ensure reliable attachment, while lower pressure is maintained in regions containing supporting materials to prevent their deformation. This localized pressure distribution achieves both reliable bonding and shape retention.
3Ease of operation
If thermoplastic elastomer is used for the inner layer to provide comfort and stretch, then ease of donning and doffing is improved, but the material melts or deforms supporting materials during high pressure processing
Solution Approach 1:
The patent introduces an intermediary bonding layer or modified thermoplastic elastomer composition that acts as a mediator between the stretchable inner layer and supporting materials. This intermediary layer provides the necessary adhesion and structural integrity during high-pressure processing while protecting supporting materials from direct contact with excessive heat and pressure, thus preventing their deformation.
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
Enables the inclusion of additional support materials and features, enhancing comfort and functionality, such as improved skin grip, moisture management, and integration of therapeutic agents, while protecting sensitive components from damage during molding.
Implementation Method 1
textured mandrill creating surface modification of the interior thermoplastic elastomeric layer to allow for the addition of pads and other materials
Implementation Method 2
using heat and chemical bonding methods
Implementation Method 3
using heat and chemical bonding methods
Implementation Method 4
at least one channel for wicking
Data Source
AI summary
A prosthetic liner having a cylindrical or conical body with an open proximal end, a closed distal end, a posterior face, an anterior face, an internal thermoplastic elastomeric layer, and an external fabric layer, with a support material attached to the anterior face and a plurality of interior surface modifications on the internal thermoplastic elastomeric layer with the option of including at least one channel for wicking. The liner may be a locking or cushion liner. Also, the support material may be attached to the distal end of the liner inside of an enclosed pocket or inside of an open pocket attached to the exterior fabric layer. The support material is preferably a foam the foam selected from the group consisting of ethyl vinyl acetate, polyethylene, neoprene, ethylene propylene diene terpolymer, vinyl, silicone, and urethane. These liners allow for a bulbous formation at the distal end of a residual limb to give comfort to a user who may have a traumatic injury, scar tissue buildup, or simply seeking further comfort.