Artificial Limb Casing with Variable Shore Hardness and Composite Reinforcement
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Solution Overview
Problem
Existing artificial limb casings lack sufficient wear resistance, elasticity, and cosmetic appeal, particularly in prosthetic feet with adjustable heel height and prosthetic hands, due to limitations in materials like foam and silicone, which are prone to water ingress and have low tear propagation resistance.
Innovation Solution
An artificial limb casing made from elastomer material, such as polyurethane, with varying Shore hardness in different areas to balance durability and elasticity, featuring a concertina structure in the joint area, material reinforcements in stressed areas, and a silicone coating with a textile intermediate layer for improved sealing and natural appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If foam material is used for artificial limb casing, then elasticity and mobility are improved, but wear resistance and sealing capability deteriorate
Solution Approach 1:
The patent uses composite materials consisting of an elastomer base material combined with reinforcing agents such as textiles, fabrics, or mesh structures. This composite construction provides both the elasticity needed for mobility and the enhanced wear resistance required for durable artificial limbs.
2Adaptability or versatility
If silicone material is used for artificial limb casing, then elasticity and sealing capability are improved, but tear propagation resistance deteriorates
Solution Approach 1:
The elastomer material is combined with reinforcing agents including textiles, fabrics, or mesh structures to create a composite material that maintains the elasticity and sealing properties of silicone while significantly improving tear propagation resistance through the reinforcing framework.
Solution Approach 2:
Different regions of the artificial limb casing may have different concentrations or types of reinforcing agents to optimize local properties - higher reinforcement in areas prone to tearing while maintaining elasticity in areas requiring flexibility.
3Reliability
If elastomer material with uniform hardness is used, then wear resistance is improved, but adaptability to different body parts deteriorates
Solution Approach 1:
The patent incorporates varying concentrations, types, or distributions of reinforcing agents throughout the elastomer material to create regions with different mechanical properties. This allows high wear resistance in areas requiring durability while maintaining elasticity and softness in areas needing adaptability to body contours.
Solution Approach 2:
The physical and chemical parameters of the composite material are varied spatially - such as fiber density, fabric weave pattern, or resin content - to achieve different hardness and elasticity levels in different regions of the artificial limb casing.
4Adaptability or versatility
If separate coverings are used for different limb areas, then adaptability to different body parts is improved, but device complexity deteriorates
Solution Approach 1:
The artificial limb casing is designed as a single integrated piece with spatially varying properties rather than multiple separate coverings. The reinforcing agents are distributed throughout the elastomer to create different regional characteristics within one unified structure, eliminating the need for assembly of multiple components.
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 provides a high-wear-resistant, elastic, and compact artificial limb casing that is inconspicuous, with enhanced adjustability and long-term strength, while preventing water ingress and offering a natural appearance and feel.
Implementation Method 1
an elastomer material, for example a polyurethane material, which has a lower Shore hardness in the joint area, in the case of a prosthetic foot casing in particular in the ankle area, than in the end area, in the case of the prosthetic foot casings in the sole area
Implementation Method 2
In the case of prosthetic feet with an adjustable heel height, it is necessary that the ankle area of the artificial limb casing is sufficiently movable to be able to match the varying basic settings of the prosthetic foot
Implementation Method 3
In addition, the foam material is obtrusive and only has a low wear resistance. A configuration of the artificial limb casing made from silicone material is disadvantageous, since the tear propagation resistance is very low in the case of silicone
Implementation Method 4
A textile intermediate layer, in particular a fleece layer, a velour layer or a flock layer, is arranged between the silicone coating and the elastomer material in order to improve the adhesion of the silicone to the elastomer material
Data Source
AI summary
The invention relates to an artificial limb casing (1) having an insertion opening (4) for inserting the artificial limb, wherein a joint area (3) to which an end area (2) is integrally connected is formed on the casing (1). The invention further relates to a method for producing an artificial limb casing (1), wherein a textile intermediate layer (8) is applied to the outside of a hollow polyurethane substrate (9), and a silicone layer (7) is applied to the textile intermediate layer. The casing (1) is made of an elastomer material that has a lower Shore hardness in the joint area (3) than in the end area (2).