V-Shaped Annular Seal for Prosthetic Socket Vacuum Integrity
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Solution Overview
Problem
Conventional sealing sleeves for prosthetic sockets are prone to punctures, bunching behind the knee, restricted knee flexion, and tearing along the brim, due to their exposure to the outside environment and lack of secure attachment, which compromises the seal and vacuum integrity.
Innovation Solution
A sealing sheath comprising a textile tube with an annular seal having a v-shaped cross-section, positioned inside the socket and attached to the liner, provides a secure and flexible seal by using a first wing on the liner and a second wing on the socket, connected by a base, with a tapered design to maintain vacuum and prevent migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing sleeve is used outside the socket, then it provides basic sealing function, but it is prone to punctures, bunching, and restricted knee flexion
Solution Approach 1:
The sealing sheath is inverted from the conventional external placement to internal placement within the socket. The sheath extends from the proximal end of the socket inward, with the seal positioned inside the socket rather than outside. This inversion protects the seal from external damage while maintaining sealing effectiveness.
Solution Approach 2:
The sealing sheath is nested within the prosthetic socket structure. The sheath is positioned inside the socket, with its distal end extending toward the distal end of the socket and its proximal end attached to the proximal end of the socket. This nesting arrangement protects the sealing components from external environmental factors.
2Reliability
If a sealing sleeve is attached to the outside of the socket, then it provides sealing, but it bunches behind the knee and restricts knee flexion
Solution Approach 1:
The sealing mechanism is inverted from external to internal placement. By positioning the sealing sheath and seal inside the socket rather than outside, the design eliminates the bunching issue that occurs with external sleeves during knee flexion, while maintaining effective sealing through the internal configuration.
3Ease of manufacture
If a sealing sleeve is used without secure attachment, then it is simple to install, but it tears along the brim and migrates proximally
Solution Approach 1:
The sealing sheath is pre-attached to the proximal end of the socket during manufacturing or assembly, before use. This preliminary attachment secures the sheath in place, preventing proximal migration during donning and use, while the integrated design maintains installation simplicity.
Solution Approach 2:
The sealing sheath is merged with the socket structure through attachment at the proximal end. This combination creates a unified assembly where the sheath and socket work together, preventing relative movement and migration while maintaining a simple overall installation process.
4Device complexity
If the seal is attached directly to the liner, then it simplifies the structure, but it does not allow for optimal placement and higher vacuum sockets
Solution Approach 1:
The sealing system is segmented into distinct components: the sealing sheath, the annular seal, and the socket. This segmentation allows the seal to be optimally positioned within the socket at a distance from the liner, enabling higher vacuum levels while maintaining a manageable structural complexity through modular design.
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 enhances the reliability of the seal by protecting it from external damage, maintaining vacuum integrity, and allowing for greater joint flexibility, reducing issues like punctures and tearing, while enabling easier replacement of the sheath if damaged.
Implementation Method 1
By removing the air in the socket the prosthesis is held closer to the residual limb during swing phase reducing the accelerated impact at heel strike.
Implementation Method 2
The seal arrangement includes a cuff-like base with a sealing lip on an outside thereof. The lip has two flaps to seal on both the liner and inner socket wall
Implementation Method 3
An annular seal, e.g. an elastomeric or silicone seal, is positioned adjacent a proximal end of the textile tube and continuously extends from an inside of the textile tube
Implementation Method 4
The textile tube may define a wicking layer for distributing vacuum within an area defined between the liner and the prosthetic socket
Data Source
AI summary
The sealing sheath is for use with a prosthetic socket and associated liner. The sealing sheath includes a textile tube for surrounding at least a portion of a liner that is configured to wear on a residual limb. An annular seal, e.g. an elastomeric or silicone seal, is positioned adjacent a proximal end of the textile tube and continuously extends from an inside of the textile tube configured to be adjacent the liner, through the textile tube to an outside thereof configured to be adjacent an inside of the prosthetic socket. The annular seal may include a first wing on an inside of the textile tube configured to be adjacent the liner, a second wing on an outside of the textile tube configured to be adjacent an inside of the prosthetic socket, and a base connecting lower ends of the first and second wings to define a v-shaped cross-section of the annular seal.