Prosthetic Socket with Polycentric Joint and Torsion Spring
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Solution Overview
Problem
Conventional upper extremity prosthetic devices are expensive, time-consuming to produce, and often result in heavy, robotic-looking devices that are unsuitable for many users, particularly children, due to their high cost and the manual labor-intensive process of creating sockets that fail to conform to objects naturally.
Innovation Solution
A socket system for prosthetic upper extremity that includes a proximal and distal socket portion connected by a joint with a biasing element, such as a torsion spring, and a tensioning system with axially extending ribs and a lace to ensure a comfortable and natural fit, along with a polycentric joint for enhanced mobility and muscle sensor integration for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manual socket creation process is used, then custom fit is achieved, but manufacturing time and cost increase significantly
Solution Approach 1:
The socket is divided into modular components including a removable distal portion and proximal portion that can be independently manufactured and assembled. This segmentation allows for faster production while maintaining custom fit through the coupling mechanism that adapts to the residual limb.
Solution Approach 2:
The socket incorporates adjustable parameters including a tensioning system with lace and tensioner that can be modified to fit different residual limb configurations. This allows rapid adjustment without requiring complete remanufacturing, reducing both time and cost.
2Manufacturing precision
If conventional manual socket creation process is used, then custom fit is achieved, but production cost increases significantly
Solution Approach 1:
The socket is divided into modular components including a removable distal portion and proximal portion that can be independently manufactured and assembled. This segmentation allows for faster production while maintaining custom fit through the coupling mechanism that adapts to the residual limb.
Solution Approach 2:
The socket incorporates adjustable parameters including a tensioning system with lace and tensioner that can be modified to fit different residual limb configurations. This allows rapid adjustment without requiring complete remanufacturing, reducing both time and cost.
3Ease of operation
If biasing element is added to joint, then mobility is improved, but device complexity increases
Solution Approach 1:
The biasing element is configured to automatically maintain the distal socket portion in a flexed position without requiring external control systems. The spring self-regulates the joint position, providing mobility while minimizing added complexity through passive mechanical operation.
4Ease of operation
If tensioning system with lace and ribs is added, then comfort and fit are improved, but device complexity increases
Solution Approach 1:
The tensioning system utilizes a lace element that passes through axially extending ribs to create flexible, adjustable compression around the residual limb. This flexible film approach provides customized fit and comfort while maintaining relatively simple construction compared to rigid adjustment mechanisms.
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 socket system provides a cost-effective, lightweight, and naturally conforming prosthetic solution that overcomes the limitations of conventional devices by allowing for a more comfortable and functional upper extremity prosthesis with improved mobility and control.
Implementation Method 1
The joint may include a biasing element connecting the proximal socket portion to the distal socket portion so that, in the absence of applied force, the biasing element tends to move the distal socket portion from an extended condition relative to the proximal socket portion to a flexed condition relative to the distal socket portion. The biasing element may be a torsion spring
Implementation Method 2
The tensioning system may include a tensioner and a lace that circumscribes an outer surface of the socket. First and second ends of the lace may be coupled to the tensioner, and rotation of the tensioner may tension the lace to cause at least some of the plurality of axially extending ribs to flex inwardly.
Implementation Method 3
Muscle sensors may be molded into the socket to sense specific muscles that are used to control the hand. These sensors may use surface electrodes to sense the electrical activity of the user's muscle.
Data Source
AI summary
A socket may be for coupling a prosthetic upper extremity to a residual limb of a user. The socket may include a proximal socket portion and a distal socket portion coupled to the proximal socket portion by a polycentric joint. The polycentric joint may include a plate having a first end coupled to the proximal socket portion via a first fastener, and a second end coupled to the distal socket portion via a second fastener. The proximal socket portion may be rotatable relative to the distal socket portion about a first axis passing through the first fastener and about a second axis passing through the second fastener.