Adaptable Prosthesis Shaft Stiffness Adjustment
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Solution Overview
Problem
Conventional lower limb prosthetic sockets face challenges in adapting to the changing shape and volume of the residual limb due to daily volume fluctuations and posture changes, leading to discomfort and instability, especially when transitioning from standing to sitting.
Innovation Solution
A prosthetic socket with an outer socket featuring an adjustable peripheral section that can change its stiffness and shape through an integrated adjustment device, allowing the circumference to remain constant while adapting to different limb shapes and volumes, enabling easy adjustment by the wearer without tools or removing clothing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer socket is made rigid to transmit forces effectively, then force transmission between the body and prosthesis is improved, but pressure on the residual limb increases causing discomfort and pain
Solution Approach 1:
The prosthetic socket is divided into two distinct parts: a rigid outer socket for force transmission and a soft inner socket for comfort. Each part performs its specific function optimally - the outer socket provides structural strength while the inner socket cushions pressure points on the residual limb.
Solution Approach 2:
The prosthetic socket combines two different materials with contrasting properties - a rigid material for the outer socket and a soft elastic material for the inner socket. This composite structure allows the device to simultaneously achieve force transmission strength and pressure distribution comfort.
2Stability of the object's composition
If the outer socket is made rigid to maintain stability during standing and walking, then stability is improved, but adaptability to changing limb shape and volume deteriorates
Solution Approach 1:
The inner socket is designed as a dynamic component that can deform and adapt to changes in residual limb shape and volume throughout the day. This dynamic flexibility allows the socket to accommodate swelling, muscle atrophy, and posture changes while the outer rigid socket maintains overall structural stability.
Solution Approach 2:
The inner socket is constructed from a soft, elastic material that forms a flexible shell capable of conforming to the residual limb's changing contours. This flexible inner layer absorbs dimensional changes while the rigid outer socket preserves structural integrity.
3Adaptability or versatility
If the circumferential section is made elastic to accommodate shape changes, then adaptability is improved, but structural strength and rigidity deteriorate
Solution Approach 1:
The circumferential section is segmented into an inner elastic portion and an outer rigid portion. The inner elastic circumferential section accommodates shape changes and provides adaptability, while the outer rigid circumferential section maintains structural strength and prevents excessive 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
The adjustable prosthetic socket provides enhanced comfort and stability by accommodating shape changes, ensuring a secure fit and necessary strength for walking and standing while allowing for reduced stiffness and volume when sitting, thus improving overall wearability and functionality.
Implementation Method 1
The outer shaft has a circumferential section, preferably elastic
Data Source
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AI summary
The invention relates to a prosthesis shaft (100) for the lower extremity. The prosthesis shaft comprises an outer shaft (1) for receiving an inner shaft (25) in the interior of the outer shaft, and the inner shaft (25) is designed to receive a limb stump of the lower extremity in the interior of the inner shaft. The outer shaft (1) has a circumferential portion (9), and the prosthesis shaft (100) further contains or has at least one adaptation device (11) which is part of the outer shaft (1) or is connected or can be connected to the outer shaft (1). The adaptation device (11) is designed and arranged so as to cause or allow a change in the shape of the outer shaft (1) or a change in the stiffness of the prosthesis shaft (100) or the outer shaft (1) at least in the region of a circumferential portion (9) upon being actuated while the circumference of the circumferential portion (9) remains unchanged.