Prosthesis Socket Adapter Thermal Expansion Mismatch
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Solution Overview
Problem
Conventional socket systems for prostheses often experience rattling noises due to play between the adapter element and the prosthesis socket caused by differing coefficients of thermal expansion, leading to insecurity and discomfort for the wearer.
Innovation Solution
Designing the adapter element with a main body made of a second fiber-reinforced plastic, matching the thermal expansion coefficient of the first fiber-reinforced plastic used for the prosthesis socket, to eliminate play and ensure a secure, stable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the adapter element is made of aluminum to reduce weight and manufacturing cost, then the prosthesis becomes lighter and cheaper to produce, but thermal expansion differences cause play and rattling noises between the adapter element and prosthesis socket
Solution Approach 1:
The patent changes the material parameter of the adapter element from aluminum to fiber-reinforced plastic, specifically selecting materials with matching coefficients of thermal expansion. This parameter change eliminates the thermal expansion mismatch that causes play and rattling noises, while maintaining the weight advantage through the use of lightweight composite materials.
Solution Approach 2:
The patent employs fiber-reinforced plastic as a composite material for the adapter element. This composite material provides both the weight reduction needed for comfortable wear and the dimensional stability required to match the thermal expansion characteristics of the prosthesis socket, thereby eliminating connection instability.
2Ease of manufacture
If the adapter element is made of aluminum for ease of manufacture and low cost, then production becomes simpler and more economical, but the differing thermal expansion coefficient causes play during temperature changes
Solution Approach 1:
The patent changes the material parameters of the adapter element to fiber-reinforced plastic with specifically selected thermal expansion properties. This allows the material to match the dimensional stability requirements of the prosthesis socket while maintaining ease of manufacture through conventional composite processing techniques.
3Strength
If a form-fit connection is used between the adapter element and prosthesis socket to ensure secure attachment, then connection strength is improved, but play occurs due to thermal expansion differences during curing and cooling
Solution Approach 1:
The patent changes the material composition parameter of the adapter element to fiber-reinforced plastic with matched thermal expansion characteristics. This ensures that the form-fit connection maintains its dimensional stability during the exothermic curing process and subsequent cooling, preventing the development of play while preserving the strength of the connection.
Solution Approach 2:
The patent achieves homogeneity in the thermal expansion behavior between the adapter element and prosthesis socket by selecting fiber-reinforced plastic materials with matching coefficients. This homogeneous thermal response prevents differential expansion and contraction that would otherwise cause play in the form-fit connection.
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 effectively suppresses rattling noises, enhances the confidence and security of the prosthesis wearer by ensuring a stable and secure attachment of distal prosthetic elements, while allowing the prosthesis to be used in water without rusting or damage, and reducing manufacturing costs.
Implementation Method 1
different coefficients of thermal expansion, leading to play between the adapter element and the prosthesis socket upon cooling
Data Source
AI summary
The invention relates to a socket system for a prosthesis. The socket system including a prosthesis socket which has a proximal opening for receiving a residual limb and a distal end and which is made, at least partially, of a first fiber-reinforced plastic. The socket system also includes an adapter element which is arranged on the distal end of the prosthesis socket and is designed in such a manner that a distal prosthesis element can be secured to the adapter element. The adapter element includes a base body which is made, at least partially, of a second fiber-reinforced plastic.